LATIDITUDINAL CHANGES OF LATIDITUDINAL CHANGES OF PLANKTON AND NEKTON BIOMASSES PLANKTON AND NEKTON BIOMASSES IN THE WESTERN TRANSITION ZONE IN THE WESTERN TRANSITION ZONE Vadim Vadim F. F. Savinykh Savinykh , Vladimir A. , Vladimir A. Shelekhov Shelekhov , Svetlana V. , Svetlana V. Davydova Davydova , Svetlana V. , Svetlana V. Naydenko Naydenko , , Alexey Alexey A. A. Baytaluk Baytaluk , , Gennady Gennady V. V. Khen Khen , , Gennady Gennady A. A. Shevtsov Shevtsov and Mikhail A. and Mikhail A. Zuev Zuev Pacific Scientific Research Fisheries Center (TINRO Pacific Scientific Research Fisheries Center (TINRO - - Center), Center), 4 4 Shevchenko Shevchenko Alley, Vladivostok, Russia, 690950 Alley, Vladivostok, Russia, 690950
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LATIDITUDINAL CHANGES OF LATIDITUDINAL CHANGES OF PLANKTON AND NEKTON BIOMASSES PLANKTON AND NEKTON BIOMASSES IN THE WESTERN TRANSITION ZONEIN THE WESTERN TRANSITION ZONE
VadimVadim F.F. SavinykhSavinykh, Vladimir A., Vladimir A. ShelekhovShelekhov, Svetlana V., Svetlana V.DavydovaDavydova, Svetlana V., Svetlana V. NaydenkoNaydenko,, AlexeyAlexey A.A. BaytalukBaytaluk,,
GennadyGennady V.V. KhenKhen,, GennadyGennady A.A. ShevtsovShevtsov and Mikhail A.and Mikhail A. ZuevZuev
Pacific Scientific Research Fisheries Center (TINROPacific Scientific Research Fisheries Center (TINRO--Center), Center), 44 ShevchenkoShevchenko Alley, Vladivostok, Russia, 690950Alley, Vladivostok, Russia, 690950
INTRODUCTIONINTRODUCTION
Western Transition zone is one of the most Western Transition zone is one of the most productivity fishery regions of the World. productivity fishery regions of the World.
There is feeding area for Japanese sardine, There is feeding area for Japanese sardine, PacificPacific saurysaury, Anchovy, Mackerels, Skipjack, , Anchovy, Mackerels, Skipjack, Japanese flying squid, Neon flying squid etc. Japanese flying squid, Neon flying squid etc. However biomass and species composition ofHowever biomass and species composition ofepipelagicepipelagic community of this area have the community of this area have the
evident differences from north to south.evident differences from north to south.
INTRODUCTIONINTRODUCTION
There areThere are differentsdifferents points of view on the points of view on the productivity of Western Transition zone. Most part productivity of Western Transition zone. Most part
of investigators are concordant that total of investigators are concordant that total productivity of this area decreases from north to productivity of this area decreases from north to south. However our studies show that there are south. However our studies show that there are
different trends for upper and lowerdifferent trends for upper and lower trophictrophic layers. layers. The subject of this paper is characteristic of The subject of this paper is characteristic of
plankton and nekton community of the Western plankton and nekton community of the Western Transition zone in the November, 2001. Transition zone in the November, 2001.
GOALS AND OBJECTIVESGOALS AND OBJECTIVES
There areThere are differentsdifferents points of view on the points of view on the productivity of Western Transition zone. Most part productivity of Western Transition zone. Most part
of investigators are concordant that total of investigators are concordant that total productivity of this area decreases from north to productivity of this area decreases from north to south. However our studies show that there are south. However our studies show that there are
different trends for upper and lowerdifferent trends for upper and lower trophictrophic layers. layers. The subject of this paper is characteristic of The subject of this paper is characteristic of
plankton and nekton community of the Western plankton and nekton community of the Western Transition zone in the November, 2001. Transition zone in the November, 2001.
Materials and methodsMaterials and methods
•• The data were collected during R/V “ProfessorThe data were collected during R/V “ProfessorLevanidovLevanidov” in the November, 2001” in the November, 2001
•• MidwaterMidwater trawl with mouth diameter about 40 m was trawl with mouth diameter about 40 m was used for nekton collectionused for nekton collection
•• Trawl tows wereTrawl tows were condactedcondacted by stepby step--byby--step methods step methods in the upper 200 m layerin the upper 200 m layer
•• Standart JedyStandart Jedy net with mouth diameter 37 cm was net with mouth diameter 37 cm was used for plankton collectionused for plankton collection
•• Plankton wasPlankton was devideddevided into 3 fractions: small, middle into 3 fractions: small, middle and largeand large--sizedsized
Materials and methodsMaterials and methods•• Oceanographic studies Oceanographic studies
were carried out in the were carried out in the upper 500 m layerupper 500 m layer
•• We used TSWe used TS--analysis analysis method for water masses method for water masses determinationdetermination
•• As a result, for types of As a result, for types of water masses were water masses were marked out
0 5 10 15 20Temperature, °C
-500
-400
-300
-200
-100
0
Dep
th, m
WSA
FSAFST NST
32.0 32.5 33.0 33.5 34.0 34.5 35.0Salinity, psu
-500
-400
-300
-200
-100
0
WSA
FSAFST NST
010203050
75100 150
200250300350400450
500
32.5 33.0 33.5 34.0 34.5 35.0Salinity, psu
0
5
10
15
20
Tem
pera
ture
, °C
010203050
75
100
150
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250
300350400450
500
010203050
75
100
150
200250
300350400
500
01020305075
100
150200250300350400450500
WSA
FSA
FST
NST
marked out
Surface water massesSurface water masses disrtibutiondisrtibution
•• Phytoplankton was found only in the Phytoplankton was found only in the Transformed Subarctic (TSA) and Transformed Subarctic (TSA) and Transformed Subtropical (TST) waters.Transformed Subtropical (TST) waters.
•• CoscinodiscusCoscinodiscus, , ChaetocerosChaetoceros andandThalassiosiraThalassiosira were abundantwere abundant generasgeneras..
Biomass of smallBiomass of small--sized zooplankton sized zooplankton (small copepods (small copepods were dominate species: were dominate species: Oithona similis, Pseudocalanus Oithona similis, Pseudocalanus
Biomass of middleBiomass of middle--sized sized zooplankton zooplankton (copepods (copepods –– Metridia pacificaMetridia pacifica ––dominated, larvae ofdominated, larvae of euphausiidseuphausiids, small, small sagittassagittasandand pteropodspteropods also were found)also were found)
0
10
20
30
40
50
60
70
80
S A TS A TS T S T
Bio
mas
s, m
g/m
3
Biomass of largeBiomass of large--sized zooplankton sized zooplankton ((saggitassaggitas, copepods,, copepods, euphausiidseuphausiids,, hyperiidshyperiids andandsalpassalpas dominated)dominated)
0
200
400
600
800
1000
1200
1400
S A TS A TS T S T
Biom
ass,
mg/
m3
Nekton compositionNekton composition
0%10%20%30%40%50%60%70%80%90%
100%
S A TS A TS T S T
S quidsFis hes
Nekton densityNekton density
0
5
10
15
20
25
30
S A TS A TS T S T
Dens
ity, t
ons
per s
q. k
m
S quidsFis hes
Dominated species and groupsDominated species and groups
0%10%20%30%40%50%60%70%80%90%
100%
S A TS A TS T S T
Other planktivorousOther predator s quidsOther predator fis hesTunas and s wordfis hNeon flying s quidFireball s quidMyctophidsAnchovy
Small pelagicSmall pelagic planktivourosplanktivouros are are dominating in the all water massesdominating in the all water masses
•• Japanese anchovy Japanese anchovy (length less than 15 (length less than 15 cm)cm)
•• MyctophidsMyctophids (length (length less than 15 cm)less than 15 cm)
Fireball squid (mantle Fireball squid (mantle length less than 7 cm)length less than 7 cm)
Predators’ densityPredators’ density
0
0,5
1
1,5
2
2,5
S A TS A TS T S T
Dens
ity, t
ons
per s
q. k
m
There are different trends for There are different trends for predators and smallpredators and small pelagicspelagics
Pre dators
0
0,5
1
1,5
2
2,5
S A TS A TS T S T
Dens
ity, t
ons p
er sq
. km
Small planktivourus
0
5
10
15
20
25
30
S A TS A TS T S T
Dens
ity, t
ons p
er sq
. km
ObservationsObservations
•• There are different trends of biomass changes There are different trends of biomass changes for the plankton and nekton communities.for the plankton and nekton communities.
•• Most productive area is transition zone Most productive area is transition zone between Western Subarctic gyre and Northern between Western Subarctic gyre and Northern Subtropical one.Subtropical one.
•• Commercial fishery would be more effective in Commercial fishery would be more effective in the subtropical waters.the subtropical waters.
•• There is evident lack of predators in the There is evident lack of predators in the Subarctic and Transformed Subarctic waters. Subarctic and Transformed Subarctic waters.
Is the high abundant smallIs the high abundant small pelagicspelagicsthe deadlock in the Subarctic the deadlock in the Subarctic
waters ecosystem?waters ecosystem?
•• More abundant species More abundant species –– Japanese anchovy Japanese anchovy –– will return on the shelf of Japanese Islands. will return on the shelf of Japanese Islands. There is a way to substance and energy There is a way to substance and energy transportation from oceanic to inshore regiontransportation from oceanic to inshore region
Is the high abundant smallIs the high abundant small pelagicspelagicsthe deadlock in the Subarctic the deadlock in the Subarctic
and squidsand squids can play the can play the significant role as a pray significant role as a pray for Pacific salmons. for Pacific salmons.
•• TheThe salmomssalmoms feeding feeding range concurs withrange concurs withnorternnortern part of Transition part of Transition zone in the winter time zone in the winter time and smalland small pelagicspelagics is ones is ones of the main food of the main food components especially forcomponents especially forcohocoho andand chinookchinooksalmons salmons
Is the high abundant smallIs the high abundant small pelagicspelagicsthe deadlock in the Subarctic the deadlock in the Subarctic
waters ecosystem?waters ecosystem?•• Transition zone is the Transition zone is the
main spawning region of main spawning region of borealboreal myctophidsmyctophids. Last . Last ones may to penetrate ones may to penetrate into Bering andinto Bering and OkhotskOkhotskSeas due to Subarctic Seas due to Subarctic Gyre circulation and, as Gyre circulation and, as result, they increase result, they increase nekton biomass in the nekton biomass in the deepdeep--sea regions of sea regions of marginal seas. marginal seas.
ResultsResults
•• Our data suggest that plankton and Our data suggest that plankton and nekton biomasses distribution was not nekton biomasses distribution was not typical in November, 2001.typical in November, 2001.
•• Is there mistake orIs there mistake or reguliratreguliratyy??
Our subsequent studies shown that Our subsequent studies shown that there wasthere was tradionaltradional plankton and plankton and nekton abundance pattern in the nekton abundance pattern in the summer, 2002. Phytoplankton, summer, 2002. Phytoplankton, largelarge--sized zooplankton and nekton sized zooplankton and nekton density were decreased from north density were decreased from north to south whereas smallto south whereas small--sized sized zooplankton andzooplankton and ichthyoplanktonichthyoplanktonabundance was increased abundance was increased southward.southward.
Phytoplankton distribution in the Phytoplankton distribution in the July, 2002July, 2002
LargeLarge--sized zooplankton sized zooplankton distribution in the July, 2002distribution in the July, 2002145° 146° 147° 148° 149° 150° 151° 152° 153° 154° 155° 156° 157° 158° 159°
38°
39°
40°
41°
42°
43°
44°
45°
46° 6463
0
40
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500
1000
ConclusionsConclusions
•• There isThere is tendencetendence of increasing of plankton and of increasing of plankton and nekton density in northward direction. However, nekton density in northward direction. However, main ecological groups trends are different.main ecological groups trends are different.
•• Seasonal aspects heavy affect to productivity of Seasonal aspects heavy affect to productivity of different waters. Biomass ofdifferent waters. Biomass of epipelagicepipelagiccommunity of western Transition zone changes community of western Transition zone changes according to horizontal and vertical migrations of according to horizontal and vertical migrations of zooplankton and nekton.zooplankton and nekton.
ConclusionsConclusions
•• Stationary view on the dynamic of Stationary view on the dynamic of plankton and nekton community are not plankton and nekton community are not best approach. We must to store best approach. We must to store knowledge about communities status in all knowledge about communities status in all season for understanding how Western season for understanding how Western Transition zone ecosystemTransition zone ecosystem functionatesfunctionates. .
THANK YOU FOR YOUR THANK YOU FOR YOUR KIND ATTENTIONKIND ATTENTION
