Surveying and Monitoring Distribution and Population Trends of the Giant Otter (Pteronura...

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HABITATArbeitsberichte derAKTION FISCHOTTERSCHUTZ e.V.

16

ISSN 0936-2630 ISBN 3-927650-26-9 1. Edition 2005 1 - 500

Satz: Matthias HofmannHerstellung: Biblos, Tizn y Bueno 639, Lima 11, Peru

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Der Druck dieser Ausgabe wurdedankenswerterweise ermglicht durch

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HABITAT is published irregularly by Publishing company GN-Gruppe Naturschutz GmbHSudendorfallee 1, D-29386 HankensbttelAll rights reserved, inclusive reprints in extracts, photo-mechanical or digital reproductions, and the use by databanksor similar institutions.

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Printing of this issue was kindlyenabled by a subsidy of the Frankfurt

Zoological Society.

Claus Reuther , Dr. Oskar Klsch, Prof. Dr. Willfried Janen

Surveying and Monitoring Distribution and Population Trendsof the Giant Otter (Pteronura brasiliensis)

Guidelines for a Standardisation of Survey Methods as recommended by

the Giant Otter Section of the IUCN/SSC Otter Specialist Group

byJessica Groenendijk, Frank Hajek, Nicole Duplaix, Claus Reuther ,

Paul van Damme, Christof Schenck, Elke Staib, Rob Wallace, Helen Waldemarin,Raphael Notin, Miriam Marmontel, Fernando Rosas, Galia Ely de Mattos,Emanuela Evangelista, Victor Utreras, Geovanna Lasso, Hlne Jacques,

Keila Matos, Indranee Roopsind, Juan Carlos Botello


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Dedicated to the memory of Claus Reuther

The worlds otter species have recently lost their most tireless and dedicated campaigner, and we have lost

a dear friend and colleague. Claus was a highly charismatic, dynamic, respected man whose immense energywas devoted to the conservation of otters and their aquatic habitats and to the support of those who worked with

them. He was the driving force behind the standardisation of survey methods for all otter species and it is to agreat extent thanks to him that we can now present survey guidelines for the giant otter.

Claus, we will miss you.

Claus Reuther, Chairman of the IUCN/SSC Otter Specialist Group and of the Executive Board of AktionFischotterschutz, died on the 29th of December, 2004


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CONTENTS

Authors and Contributors ....................................................................................... 2

Foreword ............................................................................................................... 3

Preface ................................................................................................................. 4

Glossary ................................................................................................................ 5

1. IntroductionJessica Groenendijk ....................................................................................................... 6

2. Standard Field Survey Techniques for the Giant Otter (SFST-GO)Jessica Groenendijk, Nicole Duplaix, Frank Hajek, Christof Schenck, Elke Staib............... 11

3. The Range-wide Distribution Survey Strategy (RDSS-GO) and the StandardDistribution Survey Method (SDSM-GO) for the Giant OtterJessica Groenendijk, Claus Reuther, Frank Hajek, Paul van Damme, Nicole Duplaix ......... 31

4. Population Census Methodology Guidelines for the Giant Otter (PCMG-GO)Frank Hajek, Jessica Groenendijk, Christof Schenck, Elke Staib ..................................... 48

5. Ideas and Suggestions for Further ResearchJessica Groenendijk, Nicole Duplaix, Paul van Damme, Frank Hajek, Claus Reuther ......... 57

6. References ...................................................................................................... 59

Appendices

1. Signs and Sightings of the Neotropical Otter (Lontra longicaudis)Jessica Groenendijk, Helen Waldemarin, Nicole Duplaix ................................................. 61

2. Content for Laminated Field tips and Techniques for Giant Otter Surveys ......... 66

3. Recommended Literature for Surveyors ........................................................... 72

4. Model for a Giant Otter Survey and Finding Report ........................................... 73

5. Model for a Giant Otter Survey QuestionnaireJessica Groenendijk, Rob Wallace................................................................................. 91

6. Geographic Considerations Regarding Otter SurveysClaus Reuther ............................................................................................................. 94

7. Preliminary Notes on Selecting/Capacitating New Surveyors

Nicole Duplaix ............................................................................................................. 97

8. Addresses of Authors and Contributors ............................................................. 99


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Authors and Contributors

Jessica Groenendijk, Frankfurt Zoological Society, Peru

Frank Hajek, Frankfurt Zoological Society, Peru

Dr. Nicole Duplaix, The Oceanic Society,France

Claus Reuther, Aktion Fischotterschutz e.V., Germany

Dr. Paul van Damme, Associacin FaunAgua / Centre for Limnology and Aquatic Resources,Bolivia

Dr. Christof Schenck, Frankfurt Zoological Society, Germany

Dr. Elke Staib, Germany

Dr. Rob Wallace, Wildlife Conservation Society, Bolivia

Dr. Helen Waldemarin, Projeto Ecolontras / Associao Ecolgica Ecomarapendi, Brazil

Raphael Notin, Frankfurt Zoological Society, Peru

Dr. Miriam Marmontel, Instituto de Desenvolvimento Sustentavel Mamiraua / WC S,Brazil

Dr. Fernando Rosas, Instituto Nacional de Pesquisas da Amaznia, Brazil

Galia Ely de Mattos, Instituto Nacional de Pesquisas da Amaznia, Brazil

Emanuela Evangelista, Amazon Association, Italy

Victor Utreras, Wildlife Conservation Society, Ecuador

Geovanna Lasso, Fundacin Numashir, Ecuador

Dr. Hlne Jacques, France

Keila Matos, Universidad Nacional Experimental Ezequiel Zamora UNELLEZ,Venezuela

Indranee Roopsind, Iwokrama Intl. Centre for Rainforest Conservation and Development,Guyana

Juan Carlos Botello, Fundacin Zoologica de Cali, Colombia

2


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This publication represents important progress in the

conservation of the giant otter (Pteronura brasiliensis)

as well as for the work of the IUCN/SSC Otter Specia-

list Group. When introducing the standard for surveys

on the Eurasian Otter (Lutra lutra) for Europe during theVIIIthInternational Otter Colloquium in Valdivia, Chile, in

2001, I lamented the fact that this was the only stan-

dardised survey method for otters so far. Using the

example of the Red List assessments, I demonstrated

the need for reliable distribution data gathered by com-

parable methods.

When I encouraged the members of the IUCN/SSC

Otter Specialist Group to work on the development of

such standards also for other otter species and other

continents, I did not really expect results promptly.

However, it seems that I underestimated the enthusi-asm of the giant otter section of the Otter Specialist

Group. Its coordinator, Jessica Groenendijk, used the

long-term experience of the Giant Otter Research and

Conservation Project of the Frankfurt Zoological Socie-

ty in Peru as a basis for the development of standar-

dised methods to survey and monitor distribution and

population trends of this otter species. She succeeded

in incorporating the knowledge of a remarkable num-

ber of giant otter researchers active throughout the

speciesrange. In the process, an efficient network of

experts working on the conservation of this specieswas established.

Though the giant otter is one of very few otter species

allowing direct observations and individual identificati-

on, many basic questions regarding its conservation

still remain open. It seems that its distribution range

has decreased considerably, especially during the last

century. However, as we do not know the exact extent

of the remaining area inhabited by the giant otter we

are unable to assess the magnitude of this decrease,

the detailed conservation status of the species, and the

effects of factors such as population fragmentation.

To be able to close these knowledge gaps, a reliable

database is essential. This in turn requires such basics

as unequivocal definitions of terms, but also uniform

and comparable methods for gathering, processing, and

assessing of data. This is what we call standardisation.

Such a process not only improves the reliability of the

database, but also increases the efficiency of research

and conservation efforts.

Therefore, these first guidelines for standardised sur-vey methods for monitoring distribution and population

trends of the giant otter represent significant progress

for the conservation of this species. However, it is not

only the standarditself which constitutes this progress.The above mentioned network of experts will lay the

foundation for long-term giant otter conservation activi-

ties across national boundaries. Last but not least, thestandard will offer the opportunity of a systematic and

coordinated range-wide distribution survey strategy.

Nevertheless, we have to be aware of the fact that the-

se guidelines do not represent a final state and espe-cially not a state of perfection. This is not only because

such a standardisation process always requires com-

promises to cover scientific demands as well as prag-

matic considerations. It also needs to be understood

as a dynamic process, moved forward by improvements

resulting from each further survey. Therefore, any assi-

stance provided by (otter) specialists involved in distri-bution mapping and biological research to further increa-

se the efficiency of the methodology is welcomed.

Not only the improvement of the methodology will re-

quire additional effort. Its implementation represents the

main challenge. This will need the cooperation of all

people and institutions involved in the conservation of

the giant otter. Such cooperation requires the applicati-

on of the standardin all future surveys, as well as theprovision of organisational and financial resources.

However, at this stage I would like to thank all experts

and institutions who enabled this groundbreaking step

in giant otter conservation. Among the members of the

IUCN/SSC Otter Specialist Group, my special thanks

go to the Frankfurt Zoological Society for organising

workshops and for financing the printing of these gui-

delines, to the Associacin FaunAgua, the Instituto deDesenvolvimento Sustentavel Mamirauand the Wildli-fe Conservation Society for organising additional work-

shops, and to the German Association for Otter Con-

servation [Aktion Fischotterschutz] for providing the the

opportunity to incorporate the giant otter data in its

Information System for Otter Surveys (ISOS).

I would be glad if this report would not only increase the

quality of distribution data for the giant otter. As I alrea-

dy mentioned in my foreword to the standard survey

method of the Eurasian Otter in Europe, I also hope that

it will support the development of similar standardised

survey methods for other otter species.

Hankensbttel, December 2004

Claus Reuther

Chairman IUCN/SSC Otter Specialist Group

Foreword

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Preface

Origin of publication

The need for standardization of survey methods for all

otter species, for Latin American otter species more

specifically and for the giant otter in particular, wasemphasised during the VIII International Otter Colloqui-

um in Valdivia, Chile, in January 2001. The necessity

was reinforced during the colloquium when it became

apparent that some surveys had been recently carried

out with poorly capacitated surveyors, incorrect identi-

fication of otter sign, and faulty interpretation of data.

Thus, a first draft of field survey techniques used in

Peru by the Frankfurt Zoological Society Giant Otter

Conservation Project was produced a year later by Jes-

sica Groenendijk. However, standardising field tech-

niques for a species throughout its range requires input

from experts working in other regions/habitats. In re-cognition of this, during two courses/workshops on gi-

ant otter field survey techniques standardisation, orga-

nized by the Frankfurt Zoological Society in Peru in

November 2002 and June 2003, important contributi-

ons were made by 14 giant otter specialists represen-

ting all South American countries within the speciescurrent range of distribution.

In addition to adequately reflecting field conditions in

these countries, it was decided to design a strategy for

systematically conducting a distribution survey on arange-wide scale using a standardised method. Subse-

quent workshops in August and December 2003, orga-

nised by Associacin FaunAgua and the Instituto deDesenvolvimento Sustentavel Mamirau and WildlifeConservation Society in Bolivia and the Brazilian Pan-

tanal respectively, were instrumental in the development

of this strategy. Each of these workshops resulted in

updated versions of the document. In May 2004, a new

draft was compiled and edited by Jessica Groenendijk.

This manuscript was reviewed and revised in Novem-

ber 2004 by all authors and the final draft completed in

December 2004. Aktion Fischotterschutz, the German

Association for Otter Conservation, took on the respon-sibility of preparing the document for publication in Ja-

nuary 2005.

Authorship

It was decided to assign authorship for individual sec-

tions of the manual. Therefore, authorsare those who

have participated significantly in the writing of the ma-

nuscript, and contributorsare those who participated

in the two Peruvian field courses/ workshops and/or

provided information and comments.

Distribution

It is planned to make this document available in three

languages (English, Spanish and Portuguese) and in

three different formats: as printed hard copies, on CDs

and on the web. Please contact Jessica Groenendijk for

further information.

Acknowledgements

This document would not have been produced withoutthe institutional and financial support of the Frankfurt

Zoological Society. We are very grateful to all authors

and contributors for their hard work and patience, and

to the organizers and participants of the workshops in

Bolivia and the Pantanal for their input to the discussi-

ons. Many thanks also to Andre Brtschi, Marcela Ve-lasco, Veronica Cano and Miguel Rodriguez for their

photos.


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Glossary

The following definitions explain key terms, as used in

the text:

Surveydistribution surveys, population size estimati-

on methods, and population censuses are all types ofsurveys; the word surveytherefore refers to any oneof these or all three.

Distribution surveythe determination of the spatialoccurrence of the giant otter within a given area, ex-

pressed in terms of presence or absence, focusing pri-

marily on signs as clear indicators of giant otter

presence, but also recording any direct sightings of in-

dividuals.

Relative abundance surveyincomplete counts of

individuals within the total or sample area, or completecounts within a sample area, using established sample

count techniques, to estimate relative population abun-

dance.

Population censusa complete count of individualswithin a given area, based on direct sightings and iden-

tification, in order to obtain an absolute population size

for that area.

Monitoring involves regularly repeating distribution

surveys, relative abundance surveys, or censuses, inthe same location, over successive (periods of) years,

using the same methodology, in order to investigate

population trends and/or changes in distribution pat-

terns over time.

Population trendschanges over time (expansion/reduction) in the occupation of an area by the species,

and/or in population size of the species.

Sign these are indicative of giant otter presence.Refers only to giant otter tracks (footprints), campsites

and dens. Latrines, cylindrical scats, and scratch walls

are not considered as separate standard signs.

Campsite apatch of cleared land on the banks of

water bodies which is used regularly for defecating,

scent marking, drying out, grooming and resting. It must

have at least one latrine. Sometimes a campsite con-

sists onlyof the latrine.

Latrinesmall areas characterised by the presenceof giant otter scats and/or their remains. Every camp-

site has at least one latrine, sometimes several. Dens

may also have latrines near the entrance. Latrines do

not classify as a separate sign. If a latrine is found that

is not associated with a den, then it is recorded as acampsite.

Recently in usea broadly descriptive term for a sitewhere signs indicate giant otters are or were recently in

the area (recentlyis defined as meaning up to an esti-mated two weeks prior to the surveyor s visit).

Not recently in usea broadly descriptive term for asite where signs indicate giant otters have not recently

been in the area (not recentlyis defined as meaning an

estimated two weeks ago, or more).

Transienta sexually mature giant otter that has

left the parent group and is fully independent.


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Distribution and population data collected in a stand-ardised format is a valuable tool for the protection and

management of species and their habitats (REUTHERet al. 2000). Standardised survey methods are designedto provide reliable, comparable and user-friendly data,thereby increasing the time and cost efficiency of datagathering/processing.

The giant otter (Pteronura brasiliensis) is listed as en-dangered (EN A3ce) in the IUCN Red List (IUCN 2004).This means that a population size reduction of greaterthan or equal to 50% is suspected to be met withinthree generations (in the case of the giant otter thisrepresents approximately 21 years). The word suspect-

ed is indicative of the uncertainty we feel regardingextent of giant otter distribution and population sizes inmost parts of the species range. Although hunting forthe pelt trade is no longer an issue, this has been re-placed by a far more insidious threat: habitat degrada-tion and destruction. Deforestation, gold mining, humancolonisation along water courses, over-fishing, occa-sional hunting, poorly managed tourism, disturbances,and domestic animal diseases have all been identifiedas causal factors resulting in a reduction in habitat qual-ity for giant otters (GROENENDIJK 1998, SCHENCK and

STAIB 1998, SCHENCK 1999). However, in order to beable to assess more exactly how habitat destruction isimpacting the species, now and in the future, we ur-gentlyneed to know the current distribution and popu-lation status.

Giant otters are exceptionally well adapted to life inaquatic habitats in the tropical lowlands of South Amer-ica and are found living in rivers, creeks, lakes, reser-voirs, marshes, as well as flooded forest during the rainyseason. Figures 1 - 13 illustrate the tremendous varietyof giant otter habitats where studies/surveys are current-

ly being carried out. It is the size of the giant otters rangeand the diversity of its habitats (and the extreme isola-tion and inaccessibility of some of these) that will un-doubtedly present obstacles when implementing andrefining the proposed standard survey methodologies forthe species. However, this should be seen as a challengeto be resolved rather than a reason not to proceed.

Since the first long-term giant otter study in Surinamebetween 1976 and 1978 (DUPLAIX 1980), distributionsurveys and population censuses have been conduct-

ed in several countries of its former and present distri-bution range (SCHENCK 1999, GROENENDIJK et al.2001, VAN DAMME et al. 2002, LASSO and ACOSTA

2003, DUPLAIX 2003) but not in a standardised man-ner and with widely differing interpretations of results.

Although experiences in Peru formed the starting pointfor this document, it is hoped that it reflects and ad-dresses survey conditions and realities throughout thegiant otters range.

Establishing Guidelines for Standardisation

When establishing guidelines for a standard method forgiant otter surveys, it is fundamental to keep in mind that:defining a standard is exactly what we are attemptingto do,

it should be possible for all future giant otter surveysto adhere to the established survey standards,

simplicity and pragmatism are vital if the system isever to be widely implemented, and

the associated cost and effort is optimised in orderto justify carrying out the surveys on as large a scaleas necessary/possible.

A standard method should be equally applicable by ex-perienced giant otter researchers and by volunteers witha minimum of survey training. The standardisation proc-

ess attempts to minimise variation in collection, process-ing and interpretation of data, but it will be impossibleto factor in variation in the surveyors level of experi-ence and performance.

Also, a survey standard will not address all possiblefield circumstances, habitat realities and surveyor re-quirements. We recognise that giant otters live in a widevariety of habitats to which they respond with a spec-trum of behaviours. Therefore, what is described asusual giant otter behaviour for the sake of establishinga standard, must not be understood to imply that it is

the onlypossible behaviour that is witnessed in the field.

Furthermore, the purpose of this document is to givesurveyors a standard procedure to follow when con-ducting a giant otter survey. It is not meant to addressthe more exacting demands of research projects. Re-searchers, of course, can add to these methods of datacollection to suit their own needs but must not changethese procedures when conducting a survey.

Finally, the necessity for practicality in the field will

occasionally oblige us to define guidelines in flexibleterms (for instance, see Chapter 3 under Survey dis-tance and bank).

Jessica GROENENDIJK

1. Introduction


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Fig. 1: The Rio Negro, a blackwater river in the Pantanal, Brazil (Pho-

to: N. Duplaix).

Fig. 2: The Manu River, a whitewater river in Manu National Park, Peru

(Photo: F. Hajek).

Fig. 3: Cocha Salvador, an oxbow lake in Manu National Park, Peru

(Photo: F. Hajek).

Fig. 4: The Palma Real River, a headwater of the Madre de Dios River,

Tambopata National Reserve, Peru (Photo: F. Hajek).

Fig. 7: Blackwater creek, Manu National Park,

Peru (Photo: F. Hajek).

Fig. 6: Inside a Mauritia palm swamp, Tam-

bopata National Reserve, Peru (Pho-

to: F. Hajek).

Fig. 5: View of a Mauritia palm swamp, Tam-

bopata National Reserve, Peru (Photo:

F. Hajek).

Distribution survey

The main objective of a distribution survey is to deter-mine the spatial occurrence of the species within a

given area, expressed in terms of presence or absence,focusing primarily on signs - dens, campsites and tracks- as clear indicators of giant otter presence.

Counting and identifying giant otter individuals are nota priority in a distribution survey. Sightings and num-bers of individuals are recorded but not actively sought.Statements about giant otter abundance/density in an

area should therefore be avoided after distribution sur-veys; it is probable that several individuals or groupshave been missed or double-counted.


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Fig. 9: Akuri oxbow lake, Rupununi, Guyana (Photo: N. Duplaix).

Fig. 10: Cocha Totora, an oxbow lake covered in aquatic vegetation

Pistia sp., Manu National Park, Peru (Photo: F. Hajek).

Fig. 11: A whitewater river and associated oxbow lakes, Manu Nation-

al Park, Peru (Photo: A. Brtschi).

Fig. 12: Rapids on the Upper Coppename River, Surinam (Photo: N.

Duplaix).

Fig. 13: Balbina Reservoir, Amazonas, Brazil (Photo: N. Duplaix).

Fig. 8: The Lower Orinoco River, Orinoquia, Colombia (Photo: M. Ve-

lasco).

By targeting campsites and dens, distribution surveystend to emphasise presence/absence of residentgroups (since transient individuals have rarely been seento use campsites or dens). However, tracks can be ofgroup members or transient individuals.

When a distribution survey reveals the presence of gi-ant otters within a given area, a relative abundancesurvey or population census may be the next step. So

far, survey intensity in different countries (i.e. time pe-riod, total area covered, number of persons involved,etc.) has been highly variable.

Population census

A population census aims at counting all giant otterindividuals within a defined survey area in order to de-termine population size.To carry out a true census the following criteria mustbe approached as closely as possible (JARMAN et al.1996):1. The entire survey area, not just sample plots within

it, must be searched.2. All animals in the survey area must be detected andcounted, and none must be counted twice.


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3. The census must be conducted over a short periodso that no immigrations, emigrations, births, ordeaths occur, and in a way that ensures no animalwill evade the observer and leave the area before itis counted.

In the case of the giant otter, we are able to approxi-

mate these ideal criteria:1. Most types of giant otter habitat can be accessed

by boat (with the exception of some marsh habitats,rivers with many rapids or waterfalls, and very nar-row creeks); therefore, entire survey areas can becovered.

2. The giant otter is a large, easily visible species thatis exclusively diurnal and occupies open habitats, ingroups that are not too large to be accurately count-ed. Each individual is identifiable by its unique throatmarking making it possible to avoid double count-

ing. If fresh sign indicates that giant otters arepresent, sites are re-visited during the census untilthe group is encountered. In areas of low humandisturbance, the characteristic behaviour of giantotters to investigate intruders ensures that the sur-veyor is usually not avoided.

3. Giant otter censuses are carried out over a periodof several weeks, at the end of the dry season, whenthe water level is low and otters are restricted topermanent water bodies (therefore movement outof the census area is minimised) and the years lit-

ters are already born (therefore additional births areunlikely).

Relative abundance survey

Incomplete counts of individuals within the total or sam-ple area, or complete counts within a sample area,using established sample count techniques, allow usto estimate absolute or relative population abundance.

Although relative abundance estimates are a neces-sary and powerful tool for species conservation, the

giant otter research community is at an exploratorystage regarding the standardisation of relative abun-dance surveys. Therefore, guidelines for relative abun-dance surveys are not included in this document, butare addressed in Chapter 5.

In order to optimise the use of (limited) resources, twoor more of the described surveys may be carried outsimultaneously during a field trip.

About this document

A brief description of the layout and content of thisdocument follows:

Chapter 2describes the Standard Field Survey Tech-niques for the Giant Otter (SFST-GO). The SFST-GO at-tempts to standardise such basic aspects as the cor-rect identification and ageing of giant otter dens andcampsites, as well as filming and counting individualsin the field.Appendix 1 is added to help avoid confusion with Neo-

tropical otter (Lontra longicaudis)signs and sightingswhile Appendix 2 summarises the points that have beenhighlighted in the main body of text and can be laminat-ed for field use.Appendix 3 recommends further literature for (new) sur-veyors.

Chapter 3 presents the Range-wide Distribution Sur-vey Strategy for the Giant Otter (RDSS-GO) which in-cludes the Standard Distribution Survey Method for theGiant Otter (SDSM-GO).In contrast to the SFST-GO whichis relevant for all survey types, the Standard Distribu-

tion Survey Method addresses only distribution surveys.This is because, although many otter biologists andpolicy makers prefer to deal with otter numbers (aris-ing from population size estimation methods or popu-lation censuses that rely on sightings of animals), thisis only possible on a relatively small scale if the associ-ated cost, manpower and time budget is not to be-come prohibitive.Only distribution surveys, which are less resource-de-manding since they can determine presence/absenceof a species using sign as well as direct sightings, are

feasible, repeatable, and necessary on a national orinternational scale.

The SDSM-GO establishes standard operational guide-lines for the planning and execution of any distributionsurvey, whether at the local, regional, national or inter-national level. A model of a data collection report fordistribution surveys, and censuses, is provided in Ap-pendix 4. This form also allows the possibility of re-cording accidental field data, or data arising from pub-lications or questionnaires (Appendix 5 offers a giantotter questionnaire for use in the field). Appendix 6 gives

extra background information regarding geographicissues.

The RDSS-GO focuses on the bigger picture, on deter-mining and presenting distribution patternsin the long-term (from which - it can be argued - inferences may bemade about giant otter population trends) by coordi-nating and implementing the SDSM-GO.At this level,the strategy must address such aspects as periodicityof surveys, prioritisation of areas, personnel aspects,data handling and management, presentation and in-

terpretation of results, and funding. Preliminary noteson selecting/capacitating new surveyors are outlinedin Appendix 7.


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Chapter 4 provides Population Census MethodologyGuidelines for the Giant Otter. Due to time and costconstraints, a population census is unlikely to be car-ried out on a regional scale, let alone a national orrange-wide level. It is more probable that a populationcensus is conducted as part of a study into, for exam-ple, demographics, within a protected area or in an

area of particular conservation concern. Nonetheless,population census field methodology and data record-ing may be usefully standardized to a certain degree.

Chapter 5 offers Suggestions and Ideas for FurtherResearch which may help to improve the guidelines forstandardisation of giant otter survey methodologies.

Appendix 8 lists addresses and other contact detailsof all authors and contributors.


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Jessica GROENENDIJK, Nicole DUPLAIX, Frank HAJEK,Christof SCHENCK, Elke STAIB

2. Standard Field Survey Techniquesfor the Giant Otter (SFST-GO)

Introduction

The aim of this chapter is to act as a comprehensiveguide for the identification and ageing of giant ottersign, and the observation, counting and recording ofgiant otter groups and individuals. Errors are common-ly made during these procedures so we have gone intoconsiderable detail. However, Appendix 2 outlines themost important aspects for quick field reference.

We begin by describing characteristic signs of giantotter presence, then go on to mention two additionalsigns, cylindrical scats and scratch walls, which are lesswidely recognised or are not seen throughout the spe-cies range. Next, we indicate how to identify and agegiant otter campsites and dens, and explain the meth-odology for observing, counting and recording individu-als. Finally, we emphasise the importance of minimis-ing negative impacts of surveys on giant otters, andprovide a list of essential survey equipment.

2.1 Characteristic Signsof Giant Otter Presence Campsites, Dens and Tracks

When conducting a survey, reliably identifying signs ofgiant otter activity is sometimes the only means by whichpresence of the species can be confirmed. Familiaritywith existing giant otter literature, especially descrip-tions (including photographs and measurements) ofcampsites, dens, and tracks is therefore necessary (seeAppendix 3 for a list of recommended literature).

Campsites

Campsites are irregularly-shaped patches of land onthe banks of water bodies, which have been cleared ofvegetation (if present) and which are used for defecat-ing, scent marking, drying out, grooming and resting(DUPLAIX 1980, LAIDLER 1984, SCHENCK 1999,STAIB 2002). Sizes vary: between 0.64m and 45.05min south-eastern Peru with the average being 5.08m(STAIB 2002); in Guyana average campsite size was

30m (LAIDLER 1984); and in Surinam average size inthree different locations was 55.30m, 85.26m and54m respectively (DUPLAIX 1980).

They are often positioned well above water level anddirectly next to the water body, beneath overhangingvegetation, and in a prominent, highly visible locationsuch a river confluence, a beach, or at a sharp riverbend. They are also often associated with cross-overpoints (locations where giant otters habitually take shortcuts over land) between a river and a nearby lake, oracross a river bend (see Figures 14 - 25). Well-worn pathsmay lead from the campsite to a nearby water body.

A campsite may be used once only and then never again,

or for many years (even decades) by different groups(STAIB 2002, DUPLAIX 2003). A fresh campsite in aspecific area is usually being used by a group known tooccupy the area. However, one can never say for cer-tain that tracks on the campsite were left by that group;a transient may have stopped to investigate, for in-stance, or there may be an invasion of the territory inprogress by another group. Eventually, another groupmay use the same campsite. Over the course of years,some campsites may expand and incorporate othersnearby, especially in areas where there are few suitable

locations on a river bank. Only portions of these ex-tended sites may be used at any one time. Latrine andden locations within the campsites may change and denscollapse. Site attraction appears to be based on strate-gic location and may dictate long-term use of particularcampsites (DUPLAIX 1980, STAIB 2002).

It is important to emphasise thata campsite repre-sents a site where a variety of giant otter land activi-ties take place, and includes at least one latrine area.Sometimes a campsite will consist of a latrine only.However, a latrine that is next to a den entrance is not

recorded as a campsite.Latrines

Within each campsite there are one or more latrineareas of varying freshness, often on the periphery ofthe site, characterised by the presence of scales andother hard fish remains such as vertebrae, otoliths,teeth and large spines (for this reason, people some-times say campsites are places where giant otters eattheir prey). There are also often latrines directly belowor in front of a dens entrance. Defecation and urina-

tion on the latrine may be - but is not always - followedby thorough trampling and mixing of the scats (DUPLAIX1980, SCHENCK 1999, STAIB 2002).


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Fig. 14: Campsite on a river bend, Xixuau Reserve, Amazonas, Brazil

(Photo: E. Evangelista).

Fig. 15: Campsite behind floating vegetation, Kaburi Creek, Surinam

(Photo: N. Duplaix).

Fig. 16: Campsite with a recently used latrine, Balbina Reservoir, Am-

azonas, Brazil (Photo: N. Duplaix).

Fig. 17: Campsite hidden behind mokomoko (Montricardia arbores-cens), Kaburi Creek, Surinam (Photo: N. Duplaix).

Fig. 18: Campsite on a dry season beach, Palma Real River, Tam-

bopata National Reserve, Peru (Photo: F. Hajek).

Fig. 19: Campsite at the mouth of a small tributary, Palma Real River,

Tambopata National Reserve, Peru (Photo: F. Hajek).

Fig. 20: Campsite on a boulder, Coppename River, Surinam (Photo:

N. Duplaix).

Fig. 21: Campsite with fresh untrampled scat, Palma Real River, Peru

(Photo: F. Hajek).


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Giant otter scats are loose, dark-greenish deposits of

faeces, comprising predominantly fish scales and oth-er hard parts, as well as thick mucous. However, scatappearance may vary according to diet composition. Incampsites, scats are usually actively mixed with thoseof other group members, but occasionally untouchedscats remain on the latrine(s). These darken with thedrying action of the sun and air, so that several hoursafter having been deposited they appear black and glu-tinous. If prised apart, the interior will still be greenishin colour. Transient giant otters do not establish theirown campsites, but may visit those of groups, some-times leaving a scat that is not trampled (note, howev-

er, that an untrampled scat does not necessarily indi-cate that a transient has visited the campsite).

Evolution of the physical appearance of acampsite

When very fresh, the campsites odour is powerful andfishy and may carry far. Large numbers of insects (sweatand honey bees, ants, butterflies and flies) arrive withinhours of the otters leaving the latrine area(s). The sub-strate is damp or muddy, and nearby vegetation (twigs

and saplings) is damaged but still green (appearingbedraggled, stripped, chewed and/or muddy since ot-ters also mark by dragging leafy branches under their

bellies and pulling them down with their forearms). Leaf

litter is minimal and tracks or semicircular sweep marksmay be evident (substrate permitting). Pools of urinemay be present, again, depending on the substrate.Some dark clumps of fish hard parts may be found butmore often faeces have been mixed thoroughly withearth; scales are intact, flexible when handled, and trans-parent.

As the days pass (and the campsite is not re-visited),insect activity gradually decreases and the bees, antsand butterflies may be replaced by termites. Odour alsobecomes less pronounced (but can still be detected

close to the latrine area), and the substrate begins todry. Trampled leaves start to droop. Tracks may nolonger reach to the waters edge or may become flood-ed with changes in water level (this is particularly truefor river habitats; hence special note must be taken ofchanges in water level over time since these may beuseful indicators of the exact day when the site waslast visited by otters).

With increasing age, fish scales become separated andare dispersed by insect and bird activity and rain, the

odour becomes mustier and leaf litter starts to accu-mulate. Trampled twigs and leaves desiccate. As theweeks pass, scales become brittle and are broken down

Fig. 22: Otters resting on a sandy bank campsite, Balbina Reservoir,

Amazonas, Brazil (Photo: N. Duplaix).

Fig. 23: Campsite on a floating vegetation mat, Nanni lake, Surinam


Fig. 24: Campsite obscured from view by river bank vegetation, Manu

National Park, Peru (Photo: C. Schenck).

Fig. 25: Campsite on a small island, Patuyacu River, Tambopata Na-

tional Reserve Peru (Photo: F. Hajek).


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more readily, lose their transparency and becomeopaque or yellowish in colour.

It is very important to note that the evolution of theappearance of a given campsite is:highly weather related,dependent on location (e.g. a campsite under dense,

overhanging vegetation appears fresher for longerthan one fully exposed on a beach), anddependent on whether the otters have used the siterepeatedly (visits may be spaced several days apart,or the site may be visited daily for a period of time).

In very hot, dry weather, scats on an exposed campsitewill dry out and crumble quickly. A heavy, prolongeddownpour on a recently used campsite will give it adeceptively old appearance, erasing odours almostentirely, discouraging insects, washing off many scalesand blurring tracks. Likewise, after a light rain a camp-

site that has not been recently used may appear fresh-er than it is, having been re-activated so that it is againattractive to insects such as bees and butterflies. Thisis one of the reasons why surveys should not be con-ducted during the wet season,and rain during the dryseason is an important factor that must be taken intoaccount when estimating the age of tracks, dens andcampsites. Within a single territory there may be manycampsites and dens but only a small number are actual-ly in use at any one time. Furthermore, so far camp-site/den size and group size have been found to be

unrelated (STAIB 2002).

Dens

A den consists of one or more tunnels leading to oneor more oval chambers excavated into the bank of awater body. In Surinam, tunnel entrances with a widthof between 40 and 60cm and a height of between 30and 40cm were reported; tunnels measured 30cm to3.6m in length; and chambers measured 1.2m to 1.8min diameter and 43cm to 74cm in height (DUPLAIX1980). In Peru, measurements of a single den were

similar (STAIB 2002). Small air holes may also bepresent, and sometimes submerged entrances arefound (DUPLAIX 1980). Dens are communal, used forsleeping and cub rearing, and are frequently locatedunder root systems or fallen trees (see Figures 26 -38). A recently used den is indicated by:moist, trampled vegetation,a muddy slide or concave path (through repeated

use), and/or numerous tracks that lead from the en-trance directly to the waters edge, andusually at least one latrine which is often located ei-ther directly in front of or to one side of the denentrance, or in the immediate vicinity. In addition tothis latrine, there may be a separate campsite (with

Fig. 26: Den with a typical cleared slide down to water level, Parana

River, Xixuau Reserve, Amazonas, Brazil (Photo: E. Evange-

lista).

Fig. 27: Den high above water level, Balbina, Amazonas, Brazil (Pho-

to: E. Evangelista).

Fig. 28: Otters leaving their den at dawn, Cocha Salvador, Manu Na-

tional Park, Peru (Photo: F. Hajek).

Fig. 29: Giant otters also spread scat on latrines in front of their dens,

Manu National Park, Peru (Photo: F. Hajek).


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Fig. 30: Den under a granite ledge, Orinoco

River, Colombia (Photo: J. Botello).

Fig. 32: Den with recently excavated earth at

entrance, Xixuau Reserve, Brazil (Pho-

to: E. Evangelista).

Fig. 31: Den, Manu National Park, Peru (Pho-

to: F. Hajek).

Fig. 34: Den in the roots of a fallen tree, Manu National Park, Peru

(Photo: F. Hajek).

Fig. 35: Den at the base of a tree, Parana River, Xixuau Reserve,

Amazonas, Brazil (Photo: E. Evangelista).

Fig. 36: Den with a double entrance, Balbina Reservoir, Amazonas,

Brazil (Photo: Projeto Ariranha).

Fig. 33: Otter emerging from a den after midday rest, Manu National

Park, Peru (Photo: F. Hajek).

its own latrine(s)) nearby. Not all dens, however, havea latrine at the entrance. In dense reeds or in swampyhabitats (such as the Pantanal (MARMONTEL pers.comm.) and swamps in the Guianas), the latrine may

be many metres away on the same or opposite bank.In this case, the latrine would be recorded as a camp-site.

Spider webs, accumulation of leaf litter and/or termitetrails in or near the entrance help to indicate a den thathas not been used recently.

In the Brazilian Pantanal and reed marshes in Surinam,giant otters often sleep in the midst of vegetation, inbeds or dorms that are sculpted by their bodies. These


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Fig. 39: Tracks in mud with webbing visible, Manu National Park, Peru

(Photo: F. Hajek).

Fig. 40: Tracks in mud, claws visible, Yasuni National Park, Ecuador

(Photo: V. Ureras).

Fig. 41: Tracks in sand with webbing and claws visible, Manu National

Park, Peru (Photo: F. Hajek).

Fig. 42: Tracks in sand among rocks, Orinoco River, Colombia (Pho-

to: M. Velasco).

are usually very difficult to find as they are located un-der abundant overhanging vegetation. Some familiesonly use dorms and spend several consecutive daysor weeks in the same site (MARMONTEL pers. comm.,DUPLAIX 1980).

Transients are very discrete and there is very little in-formation available about their use of dens (STAIB2002). They sometimes excavate shallow dens for rest-ing, perhaps by expanding slightly on natural hollows,

cracks or holes in banks. It is also possible that theyseek shelter in the hollow bases of tree trunks or indense vegetation.

Fig. 37: Den, Rio Negro, Pantanal, Brazil (Photo: N. Duplaix). Fig. 38: Shallow den used by a transient. Note the untrampled scat in

the leaf litter at the entrance, Manu National Park, Peru (Pho-

to: F. Hajek).

Tracks

The most distinctive features of giant otter tracks aretheir size and their elongated toes, rather like the printsmade by the tips of human fingers (see Figures 39 to46). Measurements taken in Manu National Park (Peru),the Rio Negro (Brazilian Pantanal), and in Dortmund Zoo(Germany) show that the hind foot averages 10.5cm inwidth by 13cm in length (n=23) while the forefoot meas-ures an average of 9.5cm in width and 10.4cm in length

(n=32) (REUTHER unpubl. data). Occasionally, well usedpaths several hundred metres in length are found be-tween two different water bodies. Giant otters will some-


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Fig. 45: Giant otter left forefoot track, life-

sized (Drawing: C. Reuther).

Fig. 46: Giant otter left hindfoot track, life-

sized (Drawing: C. Reuther).

cm

0 1 2

cm0 1 2


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times investigate Neotropical otter (Lontra longicaudis)dens (and vice versa), leaving tracks on the shoreline;the tracks of the inhabitant will be found at the denentrance (see Appendix 1 for a comparison of giantotter and Neotropical otter sign measurements).

Tracks are not only associated with dens and camp-

sites; giant otters often walk over shallow beaches orriver banks, and their tracks mayprovide a useful hintof the direction they were travelling in. However, setsof tracks are not a reliable indication of the number ofotters in a group; one or more individuals may haveopted to continue by water rather than by land. On theother hand, absence of tracks does not necessarilymean absence of the species. Tracks in mud may lastand appear fresh for a surprisingly long time whereasthose in sand become blurred relatively rapidly. Othersubstrates, suchas compacted earth or rock, will notshow tracks (clearly); in these habitats, tracks are there-

fore not a useful sign of giant otter presence.

2.2 Additional Signs of Giant OtterPresence Cylindrical scats andScratch walls

The following are additional signs of giant otter pres-ence that are not mentioned in subsequent chapterssince they can be said to be less characteristic of thespecies or not encountered in all regions of the giantotters range and therefore inappropriate to include instandardised survey methodologies.

Cylindrical scats

In most regions of the giant otters range, giant otterscats do not have a defined shape, are usually tram-pled on campsite latrines, and are not deposited singly.However, in the Guianas it is not unusual to find an in-tact, (semi-) cylindrical scat that has been deposited ina location (e.g. on logs or smaller rocks, or in hollows

and outcroppings), often near rapids, that does not formpart of a campsite (see Figures 47 and 48) (DUPLAIX1980, 2003). It is thought that this is either becausethere is very little room at the site for the otters tomanoeuvre or because the vegetation/substrate doesnot allow the creation of campsites. Cylindrical scats(often referred to as single scats), ranging in lengthbetween 14 to 21cm, are generally larger than Neo-tropical otter scats. However, lengths are variable andthere is some overlap in size of scats containing crabremains. One of the most important differences between

giant otter and Neotropical otter cylindrical scats is indiameter. Giant otter cylindrical scats are 2.8 to 3.5cmin width versus a width of 0.8 to 2.5cm for the Neotrop-

ical otter. Scats with crab remains are generally largerthan scats with fish. Note that, on larger, flatter rocksor boulders, giant otters will also trample and spreadthe scat as they do on a campsite latrine.

DUPLAIX hypothesises that giant otters deposit cylin-drical scats seasonally and only in certain types of hab-

itats, namely rocky, flat granite plateaus where rivers inthe dry season are studded by numerous islands, sandbars and outcroppings. In the wet season, these cylin-drical scat sites are submerged and the otters resortto campsites (some of which are the same as duringthe dry season) that tend to be spaced further apart.Single scats are also sometimes deposited on largeroots at the base of a tree on a vertical bank wherethere is no room for a latrine. PINOS (pers. comm.) hasalso reported giant otters depositing scats on the rootbases of Mauritia palm trees (Mauritia sp.) in swamps inEcuador, because terra firme was not available to clear

campsites.

Scratch walls

A scratch wall is a vertical, often clayey patch of bank,usually near a den or campsite, which is covered in long,deep scratch marks (see Figures 49 and 50). These maybe visible for many weeks or months after the den orcampsite was last used and may therefore be a deliber-ate visual signpost. Scratch walls should not be confusedwith general entry/exit points to sites, where deep

scratches may also be present. Instead, otters seem togo out of their way to create scratch walls, sometimesparallel to the access route to the den/campsite. Theirfunction and occurrence needs to be documented fur-ther. In big cats (tigers, cheetahs etc.) scratch markson trees play an important role in territory demarcation.With more data, it may prove valuable to include scratchwalls as a characteristic giant otter sign. Note thatNeotropical otters also make scratch walls.

2.3 Identifying a Giant Otter Campsiteor Den

Giant otter campsites and dens are often misidentified.There are many other animals that eat fish, includingthe Neotropical otter, various cat species, and birdssuch as kingfishers, herons, and cormorants, any ofwhich may leave fish remains along the shore. Evenhumans may have a favourite fishing spot where theywill gradually wear away vegetation and clean fish (al-though such fishing sites will usually exhibit other signsof human presence). Other fish-eating animals do not

usually leave numerous dispersed scales, so a largeaccumulation of scales could theoretically be used as aspecific indication of giant otter presence. However, on


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Fig. 48: Untrampled cylindrical scat, Coppename River, Surinam (Pho-

to: N. Duplaix).

Fig. 47: Untrampled cylindrical scat on sand, Coppename River, Suri-

nam (Photo: N. Duplaix).

testing this assumption during thePeru field courses/workshops, it wasfound that a reliable criterion (e.g. therequirement of a minimum number ofscales) could not be established. Sim-ilarly, Neotropical otters have densthat are very similar to a giant otters(see Appendix 1), as do armadillos(Dasypodidae) and agoutis (Dasy-proctidae). In fact, agoutis, Neotropi-cal otters, and other animals some-times take-over abandoned giant ot-ter dens and may therefore give the

wrong impression that the den is stillin use by giant otters.

Correctly identifying a giant otter denor campsite is all that is required in adistribution survey; estimating wheth-er it was used recently or not is unnecessary. Duringthe field courses/workshops in Peru, a number of po-tential characteristics of giant otter sign were identifiedand tested for use in identification. These included odour,and presence of insects, trampled vegetation, a cleared

area, fish hard parts, and tracks. The characteristicsthat were found to be most useful in indicating a giantotter den or campsite are:

a cleared space or hole in the bank, fish hard parts that have been dispersed over thelatrine area, andtracks leading up to, or in, the site.

However, in some habitats a surveyor will not encoun-ter clearings or tracks. For instance, in rocky environ-ments (e.g. the Orinoco River in Colombia), giant otters

Fig. 43: Tracks down to water level at a recently used campsite, Xix-

uau Reserve, Amazonas, Brazil (Photo: E. Evangelista).

Fig. 44: Size comparison of a forefoot track, Manu National Park,

Peru (Photo: C. Schenck).

Fig. 49: Scratch wall on a clay bank, Balbina

Reservoir, Amazonas, Brazil


Fig. 50: Scratch wall at mouth of small creek,

Palma Real River, Peru

(Photo: F. Hajek).


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may establish some campsites on boulders, althoughthey will also seek out available sandy patches (Botellopers. comm.). For the sake of simplicity and clarity,these should be considered exceptions to the rule andno allowances should be made for them when stand-ardising; it is anticipated that even here giant otters willlocate sites where clearings can and are made, and

surveyors will eventually find these at some point withinthe survey area.

A cleared space is recorded as a campsite only if alayer of dispersedfish hard parts is present in the la-trine area(s) (see Key to Identifying and Ageing GiantOtter Campsites, this chapter). Finding a cleared spaceonly is not sufficient. Fish hard parts do not necessarilyhave to include scales (on some campsites in the Pan-tanal, for instance, bones and other hard parts, but noscales, were found (WALDEMARIN pers. comm.), pre-sumably due to a higher proportion of siluriformes in

the otter diet (ROSAS et al. 1999). If fish hard parts areentirely absent then either the campsite is so old that itshould not be included in the survey because the ottersmay no longer be around, or the clearing has nothing todo with giant otter activity (capybaras and tapirs oftenwear down patches on banks). If fish hard parts arefound but they are not dispersed over the latrine area(by the actions of the otters themselves), then the clear-ing does not qualify as a giant otter campsite.

A hole in the bank is only a giant otter den if dispersed

fish hard parts, and/or tracks leading up to, or in, theentrance, are present(see Key to Identifying and Age-ing Giant Otter Dens, this Chapter).Situations will arisewhere the surveyor is convinced the den or clearingqualifies as giant otter sign and is tempted to record iteven though it does not exactly meet the above crite-ria. This should be avoided; it is not necessary to lo-cate every single giant otter sign (in fact, in a stop atfirst sign survey, one is enough; see Chapter 3 underStop-at-first-sign versus Full distance surveys). But itisnecessary to allow as little room for error and ambi-guity as possible, particularly by less experienced sur-

veyors, hence the strict criteria.

2.4 Ageing a Giant Otter Campsite orDen

During a population census, dens and campsites arerecorded as being either not recently in use or recent-ly in use(this is unnecessary during a distribution sur-vey), in order to determine zones of recent activity where

more time needs to be spent in order to locate theotters.The terms not recently in use and recently inuse are relative and reflect a balance of estimates. Theword recently may have different meanings for differ-ent surveyors; therefore, here recently is broadly de-fined as meaning up to an estimated two weeks prior tothe surveyors visit.

The three primary factors (in order of priority) for deter-mining whether a site is recently in use are:presence of dispersed fish hard parts,

appearance of vegetation trampled by giant ottersduring marking, andclarity of tracks; all are influenced by recent and cur-rent weather conditions.

Other possible factors for ageing campsites/dens, suchas odour intensity, insect numbers and species, andthickness of leaf litter, were found to be too highlyvariable or prone to errors in judgment and thereforeunreliable, although they may serve as secondarycriteria to confirm a decision based on the primary

criteria (see Table 1 and Figures 51 to 57).

A campsite is only recorded as recently in use if: (1)dispersed fish hard parts are present, (2) together withmoist trampled vegetation and/or clear giant otter tracksleading up to, or in, the site (see Key to Identifying andAgeing Giant Otter Campsites, this Chapter). The wordmoist is used to describe plant material that may havebegun to wilt but is still green and not dried out (i.e. notmoist from contact with a wet otter or rain). Obviously,when there is new plant growth (seedlings, trampledsaplings that are sprouting new leaves) then this is a

clear indication that the site has not been recently used.

Table 1: Primary and secondary characteristics for identifying and ageing campsites or dens.


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Fig. 51: Giant otters trampling vegetation on a campsite, Manu Na-

tional Park, Peru (Photo: F. Hajek).

Fig. 52: Den not recently used as evidenced by new plant growth and

accumulation of leaf litter, Tambopata National Reserve, Peru

(Photo: F. Hajek).

Fig. 53: Recent, green, untrampled scat with insects on a campsite,

Palma Real River, Peru (Photo: F. Hajek).

Fig. 54: Recently trampled vegetation on a campsite, Coppename

River, Surinam (Photo: N. Duplaix).

Fig. 57: Undeteriorated, transparent fish hard

parts found on a recently used camp-

site (Photo: C. Schenck).

Fig. 56: Den in use with tracks right down to

the water level, Xixuau Reserve, Am-

azonas, Brazil (Photo: E. Evangelista).

Fig. 55: Trampled vegetation on a campsite,

Patuyacu River, Tambopata National

Reserve, Peru (Photo: F. Hajek).

A den is only recorded as recently in use if: (1) dis-persed fish hard parts are present together with eithermoist trampled vegetation and/or clear tracks leadingup to, or in, the entrance, (2) fish hard parts are ab-

sent, but moist trampled vegetation and clear tracksleading up to, or in, the site are present (see Key toIdentifying and Ageing Giant Otter Dens, this Chapter).

Correctly identifying a campsite or den as recently inuse rather than not recently in use is significant duringa population census since it justifies remaining in thearea in order to make a concerted effort to find the

group. When only old signs are encountered, then thelake/stretch of river is re-visited several days or weekslater in the hope of finding fresher evidence. When re-


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of individuals within a group (i.e. giant otter abundance/density cannot be deduced from signs of giant otterpresence).

2.5 Recording Tracks

Tracks are only recorded if found not associated withdens and campsites, or if found on dens and camp-sites where the latrines have not been recently used(possiblyindicating a visit by a transient).

2.6 Guidelines for Observing, Count-ing and Recording Giant Otters

Throat markings

Giant otters have irregular, pale throat patterns, eachof which is unique, like a persons fingerprint (DUPLAIX1980). These throat markings greatly facilitate identifi-cation of individuals from birth (see Figures 58 and59). Occasionally, dark animals are seen (almost) com-pletely lacking a throat marking; recognition is thenonly feasible though much more difficult - using otherpermanent facial or bodily features, such as scars,missing teeth, etc. During field observations, when ot-ters are most often seen in the water, it is the giantotters characteristic throat marking as well as its larg-er size, domed skull, and rounded ears that distinguish-

es it from the Neotropical otter; the latter has a moreflattened forehead, pointed ears, and lacks a markedthroat pattern (see Figures 62 and 63) However, it isvery easy to confuse the two species during briefglimpses in the field; local people do so frequently.When there is any doubt as to otter species, a giantotter sighting should not be recorded(see Figures 62and 63). Ageing and sexing individuals (see chapter 4)are not a priority during distribution surveys.

Surveying in a paddled boat

At least two people are necessary to efficiently andsimultaneously count and film a group of giant otters.It is when the animals periscope or rest on land thatthroat markings are obtained most easily (see Figures64 to 67). Ideally, with the aid of binoculars to scan theriver ahead or the shoreline, the otters are seen be-fore they see the surveyor. There are then five options:

1. To approach the group, very slowly and discreetly,so that the surveyor remains unobserved;

2. To approach without the surveyor attempting to con-ceal him/herself;

3. For the surveyor to hide amongst vegetation by theshore and wait for the otters to approach;

cent evidence is found, but the group is absent, it isadvised to re-enter the area in the afternoon, or earlymorning the following day. Time should be allowed with-in the travel schedule for a number of such re-visits. Werecommend that first-time researchers and surveyorsshould begin by charting the appearance of a den andcampsite over time, to identify the above criteria in their

own survey environment.

When a campsite or den is defined as not recently inuse it means that it has not been visited by giant ottersfor some time. It does not necessarily mean that thesite has been abandoned (i.e. that the group has nointention of ever returning). Giant otters may move to anew den and come back to the old one the next day;they may also stop using a campsite for a couple ofweeks or even months and then re-visit it. This is whythe expression abandoned should be avoided. Termssuch as fresh and old are also inappropriate since

these give rise to the tendency to categorise veryfresh, quite fresh, very old statements which havedifferent meanings to different people. Recently in useand not recently in use are also subjective phrases,but are more comprehensive and less open to differentinterpretations.

If a den or campsite is found to be not recently in useat one point during the population census, but later is re-visited by the surveyor and discovered to be recently inuse, then when reporting on the census results the fi-

nal status of that sign is recently in use (for this reason,non-recent sign should still be recorded during a popu-lation census, as an indicator of potential giant otterpresence in the area later during the census time peri-od). On the other hand, if a den/campsite is recently inuse at the beginning of the population census, and lat-er found not to have been re-used, it is still recorded asrecently in use in the census results. In summary, oldsign may become recent during a census, and recent signindicates giant otter presence, justifying further effort bythe surveyor in the area to locate the individuals.

Sometimes, a den, a latrine at its entrance, and a camp-site with one or more latrines may all be found in thesame location. In this case, both the den and the camp-site are recorded, but not the latrine since the latter isnot considered a separate sign but is part of the den.

In borderline cases, when there is doubt as to whethera den or campsite should be labelled recently in use ornot recently in use, then it is recorded as not recentlyin use.

No studies to date have shown a correlation betweenthe distribution and number of dens and campsites andthe number of giant otter groups in the area or number


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Fig. 58: Giant otter periscoping at the surveyor, Cocha Otorongo,

Manu National Park, Peru (Photo: C. Schenck).

Fig. 59: Giant otter periscoping at the surveyor, Balbina Reservoir,

Amazonas, Brazil (Photo: N. Duplaix).

Fig. 60: Close-up of a giant otter, showing rounded ears and domed

forehead (Photo: N. Duplaix).

Fig. 61: Close-up of a Neotropical otter, showing triangular ears and

flattened forehead (Photo: N. Duplaix).

Fig. 62: Side view of a Neotropical otter (Photo: N. Duplaix). Fig. 63: Neotropical otter about to submerge. During brief sightings,

without periscoping, the two species are difficult to dif feren-

tiate (Photo: C. Reuther).

Fig. 64: Otter groups will usually approach the surveyor, especially inareas where they are not persecuted (Photo: N. Duplaix).

Fig. 65: Giant otters resting on logs provide an excellent opportunityfor counting and filming. Cocha Cashu, Manu National Park,

Peru (Photo: F. Hajek).


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4. To directly head towards the group and actively forcea periscoping situation; or

5. To follow the group at a distance, while it is aware ofthe surveyors presence.

1. To approach the group, very slowly and discreetly,

so that the surveyor remains unobserved is advisedwhen the otter group is by the shore, resting on logs,or occupied on a campsite. It is preferable to observea giant otter group quietly from a distance, and to waitpatiently for opportunities to film throat markings sincethis approach causes the minimum amount of distur-bance to the otters. However, it may take longer tofilm the throat patterns of all group members by thismethod.

2. Approach without the surveyor attempting to con-

ceal him/herselfas the boat is paddled cautiously to-wards them. The otters will likely become aware of thesurveyors presence while the boat is still some dis-tance away. One or more individuals may then begin toswim rapidly towards the boat. The idea is then to stoppaddling and keep completely still. Once the first indi-vidual periscopes a term that accurately describesthe distinctive behaviour of craning neck and headstraight out of the water thereby sometimes displayingtheir entire forequarters and snorts, the others will

do likewise. To encourage the otters to feel that theyare intimidating, the surveyor should begin to paddlebackwards. This may intrigue the group and they willfollow, thereby increasing the time available for filmingthe neck markings. The boat is paddled backwards untilthey lose interest. If, after immediate viewing of thefootage, the surveyor finds that the number of throatpatterns obtained does not equal the number of indi-viduals observed, then the group can be approachedagain a little while later. The risk with this strategy isthat, since the surveyor is approaching the group in

the open, it may notice the boat while it is still too farto film adequately and, if it is a nervous group, maymove away rather than come to investigate.

3. To hide the boat amongst vegetation by the shore

and wait for the otters to approachis best if it is possi-ble to roughly predict the direction and speed the groupis travelling, allowing the surveyor to catch up and po-

sition him/herself in advance. Depending on the direc-tion of the wind, it is possible that the group will ap-proach sufficiently close for filming. The boat shouldbe near vegetation in order to break its outline andhopefully arouse their curiosity, yet should not be sohidden that they approach to within three or four me-tres before they become aware of its presence. Otterscan be very intent on what they are doing and literallyoften bump into danger before they are aware of it.The shock is then all the greater, and may reduce thetime that the group spends periscoping. In such a situ-

ation, the surveyor should make a small noise or move-ment so that the group notices before it is too close(say, at 10 metres distance). Paddles should be han-dled carefully; sudden gestures will frighten otters sothat, instead of periscoping, they submerge abruptlyand reappear at a greater distance. It is important alsoto note that a large boat moving at speed often greatlyalarms otters, especially if people stand up in the boat.

4. To directly head towards the group and actively force

a periscoping situationis justified only if it is anticipatedbeforehand that the group will be nervous, or if it has

already reacted strongly; in other words, if there is oneopportunity and the success rate has to be maximised.The idea is to approach unobserved along the shore towithin a distance of about 50m and then to head direct-ly for the group at a strategic angle, as gently as possi-ble but nonetheless at some speed (otherwise the ele-ment of surprise is lost and the otters periscope toosoon). It is important that at the moment of the survey-ors approach all the members of the group are clumpedtightly together and that they are distracted by theiractivities, otherwise one or two individuals who happen

to be nearer may spot the boat first, periscope, andthen alert the others who may not periscope at all be-fore the whole group retreats. Once the surveyor is

Fig. 66: Grooming activities also offer opportunities for filming throat

markings, Karanambu, Guyana (Photo: N. Duplaix).

Fig. 67: Giant otters resting on land (Photo: N. Duplaix).


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satisfied that as many throat markings as possible froma single periscoping session have been filmed by thismeans, the boat should be paddled away immediatelyin the hope of reassuring the group that no harm wasintended. The surveyor should not attempt the processagain with a nervous group, since the otters may leavethe area entirely for some time.

5. To follow the group at a distance that they feel com-fortable with is an option in areas where otters are tol-erant of people. Longer observation periods can beachieved and throat markings may be obtained duringnatural (nonperiscoping) activities, for example, sun-bathing, grooming and feeding near the shore.

If the sighting occurs in the afternoon, it may be possi-ble to follow the group in order to try to locate the denit is using. If the surveyor manages to remain unobservedand is able to watch the group entering the den, then he/

she can return the next day, early in the morning, beforethe group is expected to leave the den, in order to recordthroat markings of the animals as they first emerge. Therisk with this strategy is that the group may becomeaware of the surveyors presence, and subsequentlyabandon the den. This should be avoided, especially ifthe census is carried out at the beginning of the breed-ing season. If the river is sufficiently narrow, the den canbe observed from the opposite bank; the boat should behidden several metres up- or downriver (e.g. by haulingit up the bank and out of sight if it is an inflatable), and

the surveyor should walk along the shore until he/she caneasily see the den entrance while remaining hidden.

Surveying in a motor-powered boat

On faster flowing rivers, travelling by motor creates aserious noise disadvantage; otters are either aware ofthe surveyors presence well in advance and thereforehave plenty of opportunity to quietly slip away, or, aswhen negotiating a narrow, meandering river, the ot-ters are only able to pinpoint the source of the distur-bance at the last moment, which is usually also when

they are first sighted. This sudden confrontation maytake both parties by surprise, and the otters may reactby lying low (hiding amongst shore-line vegetation andremaining motionless while holding their heads justabove water level). Occasionally, however, an imminentsighting is indicated by increasingly fresh signs of giantotter presence or by waves and ripples on the watersurface ahead. The surveyor is then able to take stepsto minimise impact by:reducing speed,travelling along the middle of the river so that when a

group or individual is observed, the boat can be di-rected towards the opposite bank to maintain distance,and

avoiding shouts and sudden movements by using asignalling system.

The camera is prepared so that filming is possible imme-diately on sighting otters. In slower-flowing rivers (wherethe boat is not swept downriver), it is probably best toinstantly switch the motor off, provided that communica-tion is possible by whispering; human voices are some-

times alarming to giant otters so keeping the enginerunning but at its slowest speed may be another option.

PALMER (pers. comm.) developed a system for pas-sively approaching otters while travelling downriver, in-volving the use of two anchors to control drift speedand observation location. When a group is spotted, theengine is switched off and the first anchor is droppedoverboard to control drift speed until the desired obser-vation location is reached. The second anchor is thendropped to maintain the position. This system allowsthe surveyor to drift with the group and to adjust the

observation position when necessary.

The width of the river tends to influence giant otter re-action, as well as that of the surveyor. In narrow riversor creeks (say, less than 30m), otters often either main-tain a very low profile, swimming close to the shore orunder water to escape observation, or run up the bankand into the forest in a panic. The surveyors best op-tion is to travel slowly and to stop immediately on sight-ing the animals by steering the boat into the bank fur-thest from the otters. On wider rivers, although giant

otters are less likely to escape onshore, by swimmingdown-river with the current they easily manage to evadethe surveyor who has to react by manoeuvring the boat(sometimes a slow process). The best option in this caseis to continue upriver, or to wait, and to paddle down-river with the inflatable boat, in the hope of catching upslowly with the otters. Surveyors should never attemptto follow and catch up with an otter group at high speed;this is guaranteed to frighten the otters badly. On riv-ers, it is also more likely that a group may become splitup, with individuals adopting different escape routes.Cubs are slower to react and may become confused,

not knowing who to follow; in any such scenario, at-tempts to follow and film individuals should be aban-doned immediately to allow the otters to reassemble.

An individual which has become temporarily separatedfrom a group will normally periscope and snort (unlike atransient which tends to remain quiet). It may also uttera prolonged, loud, wavering call to which the othermembers of the group will respond immediately if theyare nearby. This contact call is sometimes used by peo-ple to attract the otters towards them for closer view-

ing (or, in the past, to hunt them for their pelts). Survey-ors may also use this contact call, but should do so asseldom as possible since it greatly agitates the group.


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It is rare to successfully fi lm all the members of a groupof otters on a single occasion. This is particularly truewhen the group is large, so repeated efforts may benecessary. Transient individuals rarely periscope, un-less taken completely by surprise. Also, they are oftenencountered only once, before they move on; it is there-fore difficult to obtain their throat patterns. It is also

difficult to know from one sighting, whether a solitaryindividual is truly transient and not a member of a grouptemporarily by itself.

Successive population censuses will reveal which ottergroups are associated with which territories, so that,as the surveyor enters a known territory, one can ex-pect to recognise the resident family (SCHENCK andSTAIB 1998, GROENENDIJK et al. 2001). However, theidentification of one known animal in a group is notsufficient to characterise the whole group. That individ-ual may have left its parent group (with which the sur-

veyor is familiar) as a transient and may have joined anunknown family as a replacement for one of the repro-ductive pair, thereby misleading the surveyor into be-lieving it is still the original group. Or, if only one or twoindividuals of a group are filmed on one occasion, andon a second occasion two different individuals of thesame group are filmed, it is easy to make the mistakeof believing that two different groups were encountered.To avoid such errors,the surveyor should aim for a 100%identification of individuals, but obtain a minimum of 60%of neck markings per group in order to identify it.

Counting individuals

Local people will very often tell the surveyor that theriver or lake being investigated is inhabited by manygiant otters or that several groups share the same ter-ritory. When a large family of giant otters is first en-countered, it is easy to gain the impression that thereare at least twenty animals. Giant otters, particularlytransient individuals, may travel large distances (tensof kilometres) within a short space of time. Groups maysplit up into smaller sub-units for short periods. It is

therefore not uncommon for people to mistakenly as-sume that more than one group is present, or that adifferent group has been found to that seen the previ-ous day. Moreover, local people sometimes believe thatgroup size is maintained year after year; if a family often individuals is regularly seen over a period of weeksor months, then in subsequent months or even years,they will tell the surveyor that the group is still com-posed of ten members when in fact there may havebeen any number of changes in group size and/or com-position.

It may be argued that if the animals are distributedalong a longitudinal survey stretch (a river) and the dis-

tance between two groups is much larger than the av-erage size of the territory of one group, identifying eachindividual may not be necessary because we can safe-ly say that the two groups are different. However, thisrequires a detailed and accurate knowledge of the sizeand/or length of giant otter territories in a wide varietyof habitats (what little published data we have suggests

that territory size is highly variable), and also the cer-tainty (which we do not have) that otter groups nevertrespass on each others territories. If two groups aresighted on the same day and the surveyor has beentravelling continuously in one direction only, it is possi-ble that the same group has been encountered twice.This is especially true on meandering rivers where gi-ant otters may use cross-over points to avoid travel-ling long stretches by river. Groups which have cubscannot travel large distances in a single day. However,transients are not hampered by others and especiallywhen moving downriver may cover large distances in a

single day. Even if the number of individuals per groupis different in two separate sightings, it could still bethe same group as it is easy to miss some membersduring a sighting. Total number of otters per group isnot a criterion for group identification. If less than 60%of throat markings are obtained per group, two differ-ent sightings of groups must be spaced at least 40kmapart, for the groups to be considered different.

While one person is filming, the other concentrates onrepeatedly counting the otters, simultaneously assist-

ing the filmer by positioning the boat and by pointingout which animals are hanging back. The number ofindividuals recorded is the total number of heads thatare seen togetherabove water at any single moment,or the total number of different neck markings filmedafter an encounter. Thus if four individuals are seensimultaneously at one point, and the surveyor stronglysuspects there is another, but all five heads were notobserved out of the water together, then the censustotal for the family should be noted as 4, indicatingthat a minimum of 4 individuals was encountered.

If the group is large (say, 8 individuals or more), it cantake an experienced surveyor several days to estab-lish with complete certainty the total number of individ-uals. Counting does not necessitate a periscoping sit-uation; in fact, it is best achieved by watching a groupfrom a distance as the members go about their normalactivities (e.g. when they go ashore). Sometimes, whengroup members move from one hunting area to anoth-er, they will do so over open water, or in a line along ariver bank, in which case their heads may all appearabove water level simultaneously for a few seconds.

The majority of cubs are born during the dry season,but wet season litters are occasionally seen so it should


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not be assumed that there are no cubs simply becauseit happens to be the wrong time of year for them. If it issuspected that the group has a litter of cubs (for in-stance, because the group returns to the den morefrequently, the female entering to nurse the cubs in-side), or if the survey is being conducted during thedry season, extra care must be taken when approach-

ing or investigating dens. Surveyors must not goashore. The family is usually much more nervous and itis possible that, when continuously disturbed, the fe-male may stop lactating due to stress (this has beenrecorded in zoos; WNNEMANN 1993) or the groupmay feel forced to abandon the den and move theircubs elsewhere, thus exposing them to danger.

Recording throat markings

Otters tend to be very aware of the presence of peo-ple, and will usually approach a boat in much the same

way as they would a large predator such as a caiman.It is rare, once a group of otters has seen a boat, forthe latter to be ignored. Normally, group members willsurround the boat, periscope and repeatedly utter ex-plosive warning snorts. Some groups are by nature muchmore wary than others; individual characters, particu-larly of the reproductive pair, and previous experienc-es with people appear to play an important role in groupreaction. In certain areas in Bolivia (for example, Isiboro-Secure National Park), giant otters have developed amarked skill in avoiding boat contacts and to remain

invisible in areas with intensive fishing boat navigation(VAN DAMME pers. comm.). In other places such as theGuianas and in the Pantanal, Brazil, groups may becomparatively relaxed in the presence of people.

When a group is exposed to people only very occa-sionally, then periscoping behaviour is usually vigorousand may last several minutes. In habitats where localpeople fish relatively frequently, the display may be ofvery short duration before the animals disappear. Some-times a group may begin to periscope while peopleare still hundreds of metres away; they may not even

have seen or heard it but may have smelled it. Such areaction suggests an association by the group with anegative experience. Generally, the longer theperiscoping display the less experience the group hasof humans; it is expressing both curiosity as well asalarm.

There are two options to record throat patterns: film-ing and photography. Filming is carried out with ahandheld digital video camcorder which has a power-ful zoom (at least 20x optical zoom) and a long-life

battery. Spare battery packs are essential; batteriesmay discharge rapidly in the tropics. Many people findcapturing giant otter throat markings with a video cam-

era much easier than with a still camera as it is unnec-essary to get so close to the otters, a video camera ismore forgiving of shake, and continuous footage isobtained. Some surveyors, however, prefer to use asemi-automatic still camera with auto focus (100% au-tomatic cameras are fragile). Still cameras have theadvantage of not requiring bulky batteries, so carrying

spares or re-charging (in areas where there is often noelectricity) is not a concern. Sorting through photo-graphs is much easier and less time consuming thanwatching many hours of film footage. Also, comparinganimals is simpler if one can place images side by side.However, if there is room in the budget for either avideo camera ora still camera, then it

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