.

BLAGRRA BLAGRRA Line TransectsLine TransectsRapid Surveys for Ecological Emergencies

www.agrra.org© E. Muller

St. John, USVISt. John, USVISept. 2005Sept. 2005

BLAGRRA Line TransectsBLAGRRA Line Transects

For rapidly assessing ecosystem-level changes in total live coral cover during,

and following, mass bleaching events, outbreaks of disease, or other acute

ecological perturbations.

Permission is granted to use the photographs in this presentation with the BLAGRRA Program and, with attribution, for other valid educational projects.

All other uses are strictly prohibited.All other uses are strictly prohibited.

RationaleRationale

© E. Muller

Mass bleaching events and some diseases cause discoloration of live coral tissues.

Elevated levels of coral mortality characterize ecological emergencies (severe environmental perturbations) in coral reefs.

Bleaching CategoriesBleaching Categories

Normal, Pale, Bleached:should be specific for the species at the particular location & habitat

© P. Dustan

palepale

normalnormal

© T. Turner© T. Turner

Deep coral (Montastraea)

palepale

bleachedbleached

© S. Zea

Shallow coral (Montastraea)

Close-up

New MortalityNew MortalityWhiteWhite skeletons are intact (unless live tissues have just been bitten by a fish or abraded), with no sediment, algae, or other visible cover.

Would have died within the previous seconds to 1 - 2 days.

Conspicuous during outbreaks of disease, bleaching-related mortality events, and just after hurricanes or other large-scale perturbations.

new mortalitynew mortality

© P. Dustan© P. Dustan

Diseased coral (Mycetophyllia)

Close-upClose-up

live tissueslive tissues

© G. Schmahl© G. Schmahl

© P. Dustan© P. Dustan

Close-up

New mortality:dead & white

Bleached: translucent tissueswithout visible algal pigments

Easily confused!Easily confused!

and

© R. Ginsburg

Close-up

© L. Benvenuti

© C. Rogers

Transitional MortalityTransitional MortalitySkeletons are mostly intact and covered with a thin layer of sediment, or biofilms, or tiny, multi-colored turf algae (unless they have just been bitten by a fish or abraded).

Would have died within the previous days to months.

Conspicuous afteroutbreaks of disease, bleaching-related mortality events, hurricanes or other perturbations. Turf algae on coral (Acropora palmata).

© P. Dustan

transitional transitional mortalitymortality

Close-up new mortalitynew mortality

Post-Bleaching MortalityPost-Bleaching Mortality

Stony corals may survive a bleaching event but later succumb to disease or from unknown causes.

Severe bleaching:tissues survive

Monitored coral (Montastraea annularis) in St. John.

Post-bleaching disease: tissues die

© J. Miller © J. Miller

Sept. 2005 Nov. 2005

Relevance to ManagersRelevance to Managers

Sites can be rapidly and repeatedly surveyed over a large spatial scale by easily trained volunteers or staff to capture the immediate + any delayed effects of a given mortality event. Results can be compared to mortality levels occurring during “routine” environmental conditions.

For example: during a severe bleaching event, mortality from bleaching is scored as new mortality.

Several months later, when this initial mortality has shifted into the transitional mortality category, any ongoing, post-bleaching mortality is scored as new mortality.

.

What else can you see here?What else can you see here?

© L. Benvenuti© L. Benvenuti

Stressed coral (Colpophyllia natans)

black-band diseaseblack-band disease

transitional mortalitytransitional mortality

new mortalitynew mortality

bleached tissuesbleached tissues

PersonnelPersonnel• 1-2 experienced divers (can be volunteers).

Field EquipmentField Equipment• Clipboard or slate with BLAGRRA Line UW-V2.0 datasheet printed on UW paper & pencils.

• 10-m long, lead-core rope, with marks at 0-m and at 10-m, and tie-off loops at each end.

• 50-cm PVC measuring pole marked in 10-cm increments + a 15-cm or 30-cm metric ruler.

• 25 cm x 25 cm PVC quadrat around which to wrap the line.

• Dive thermometer or other temperature recording device.\

See BLAGRRA Surveys & Gear-V2.0.pdf for Equipment details at: www.agrra.org/BLAGRRA

SurveysSurveys• Stratify reefs by zone and habitat.

• Randomly sample sites (at least 5/habitat, total number to vary with spatial extent of the habitat) for a representative assessment of reef condition in the area affected by the perturbation, and/or

• Strategically choose any sites of special interest for survey (e.g., within and outside an MPA).

• Survey before (if possible), during, and at intervals after, the mortality event until conditions return to “normal.”

See BLAGRRA Surveys & Gear-V2.0.pdf for Survey details at: www.agrra.org/BLAGRRA

MethodMethod• Try to record bottom temperature at site.

• Haphazardly set line; note start and end depths.

• Swim line; measure intercept lengths of all live coral tissues as normal, pale, or bleached between the 0-m and 10-m marks. (Sum = live coral cover.)

• Re-swim line and measure intercept lengths for any new mortality and any trans (= transitional) mortality. (Sum = effects of “recent” perturbations.)

• Record any interesting observations in Comments.

• Repeat for a total of 10 transects/site.

See BLAGRRA Line UW Datasheet-V2.0 for UW Datasheet & Method details at: www.agrra.org/BLAGRRA

Note: individual corals are not noted nor identified to species.

Part of a BLAGRRA Line UW-V2.0 Datasheet

• Sum all cover category numbers for each transect.

• Every day, enter all data for each dive in a separate copy of the

BLAGRRA Lines Data Entry-V2.0 spreadsheet.

• Check for accuracy.

• Store UW datasheets and data entry files in secure locations.

• Send data entry files to data@agrra.org for processing,

archiving, and possible posting online at www.agrra.org.

Part of a BLAGRRA Line Data Entry-V2.0 Spreadsheet

BLAGRRA Line TransectsBLAGRRA Line Transects

During an ecological emergency, go directly to: www.agrra.org/BLAGRRA

Optional: to rapidly assess stony coral mortality at the population-level during ecological

emergencies, see BLAGRRA Belt Transects at: www.agrra.org/BLAGRRA

For more about the AGRRA Project, see:www.agrra.org

Prepared for the AGRRA Project by: Judith C. Lang, September 2010