MARINE MAMMALS AND THE EUROPEAN TROPICAL TUNA PURSE SEINE FISHERY IN THE INDIAN AND ATLANTIC OCEANS

Transcription

1 INTERACTIONS BETWEEN WHALE SHARKS, MARINE MAMMALS AND THE EUROPEAN TROPICAL TUNA PURSE SEINE FISHERY IN THE INDIAN AND ATLANTIC OCEANS CAPIETTO Anna, PIANET Renaud, DELGADO DE MOLINA Alicia, MURUA Hilario, FLOCH Laurent, DAMIANO Alain, CHAVANCE Pierre, MERIGOT Bastien Institut de Recherche pour le Développement, France Instituto Español de Oceanografía, Spain AZTI Tecnalia, Spain Université Montpellier 2, France 1

2 Introduction Tuna fishery: Ecosystem approach to fisheries (FAO) Tuna purse seine fishery (PSF) in the Atlantic and Indian Oceans (62%) (FAO, 28) European: 7 vessels and 1% global fisheries (Pianet et al., 211) 2 French & Spanish: 42 vessels followed by IRD, AZTI & IEO since 198.

3 Search of tuna: Fish aggregating devices (FADs) Natural wood log Artificial: bamboo raft, anchored buoy Marine macroorganisms Whale sharks (WHS) Marine mammals (MAM) Catch of macroorganisms (Hall et al., 2) 3 Restrictions in IO and AO (EU, 27)

4 Objective: Distribution of the frequency of co occurrence of tuna s PSF with whale sharks and marine mammals in IO and AO. Study: The spatial and temporal distribution The impact on the mortality 4

5 Materials & Methods Purse seine logbooks [ , 31 years] high coverage (almost 1 %) one observation by set or by day declarative data and information only by species groups 5 Purse seine scientific observer program [ , 16 years] low coverage (less than 1% of trips) one observation for any change of activity during daytime or by hour independant scientific observers (species identification, size )

6 Whale sharks (Rhincodon d typus, Smith 1828): 88) Coastal and oceanic tropical waters (Roward & Brooks, 212) Vulnerable (2, IUCN) Selection of habitat and migration little known 6 NOAA

7 Whale sharks (Rhincodon d typus, Smith 1828): 88) Coastal and oceanic tropical waters (Roward & Brooks, 212) Vulnerable (2, IUCN) Selection of habitat and migration little known Marine Mammals: Tropical and temperate t waters (Schipper et al., 28) Various statutes Whale, small toothed whales and big toothed whales 7 NOAA

8 Distribution maps & statistical analyses: SPUE: Sightings i Per Unit Effort (sightings/activities) Activities: daily position during fishing activity (set) or travelling Year and season effects AO: trimester IO: monsoon and intermonsoon 8 Principal Component Analyses to investigate spatio temporal patterns.

9 Results Logbook data (IO and AO): activities with 1% of WHS and 2.3% of MAM sightings. g 55% of set among activities 9 Scientific observer data (IO and AO): activities with.1% of WHS and 1.3% of MAM sightings. MAM: 93.3% 3% of whales (WHA),.2% of big toothed whales (BTW) and 6.5% of small toothed whales (STW). 6% of set among activities

10 Whale shark distribution and annual, seasonal variation of whale shark sightings and activities iti 2 2 N % % Dim 2 (26.95%) Dim 1 (48.16%) 6 5 Season 1 Season 2 Season 3 Season 4 Activities 6 5 sigh htings activities S S 1 2 activities.1 Whale shark SPUE 2 activities.1 whale shark sighting/activity 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E years-seasons Coastal zone of Gabon (77%) Preponderance of April to September (~6 sightings)

11 1 8 Season 1 Season 2 Season 3 Season 4 Activities % % sightings activities S Season 1 Season 2 7 Season 3 Season 4 Activities S 2 3 S 1 activities.13 Whale shark SPUE 12 Activities.13 Whale shark sighting/activity 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E sig ghtings activitie es years-seasons Predominance on the Mozambique Channel Preponderance of April May (~ 8 sightings)

12 Distribution of observations, catches and mortality of whale sharks (Scientific observers data) N 1 1 S Whale shark dead 4 whale shark sightings 4 whale sharks caught 1 Whale shark dead 4 whale shark sightings 4 whale sharks caught 2 S 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E 1 S 1 2 S Whale shark dead 4 whale shark sightings 2 whale sharks caught 2 Whale shark dead 4 whale shark sightings 2 whale sharks caught 3 S 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E 12 AO: Littoral zone of Gabon. 1 mortality case (North) on 11. IO: Mozambic Channel and near to the Seychelles. hll 1 mortality case (East) on 39.

13 Indices of interactions between PSF and WHS meeting 1,% 1,% % 1,% survival,1%,1% meeting during fishing AO IO catch Spider graph (logarithmic scale) 13 Meeting=.11% Catch=.9% Meeting during fishing= 2% Survival= 98.5%

14 Marine mammal distribution and annual, seasonal variations of marine mammals sightings and activities 2 2 N % % Season 1 Season 2 Season 3 Season 4 Activities sightings a ctivities 2 1 S S 2 activities.55 Marine mammal SPUE 2 activities.5 mammal/activity 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E years-seasons Widerdistribution in comparison to WHS Coastal zone of Gabon (WHA) from April to September

15 % %) sightings 6 Season 1 Season 2 Season 3 Season activities S 1 2 S Season 1 Season 2 Season 3 Season 4 Activities S 12 activities.2 Marine mammal SPUE 12 Activities.2 Marine mammal sighting/activity 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E s sightings act tivities Seychelles (MAM) and Mozambique Channel l( (WHA) years-seasons Preponderance of December to March and April May

16 Distribution of observations, catches and mortality of marine mammals (Scientific obsever data) N 1 1 S 1 1 S 2 S 2 S Marine mammal deadd 2 Marine mammal Marine mammal deadd dead 2 marine mammal mammal sightings sightings 8 marine mammal 8 marine mammal sightings 8 marine mammals mammal caught caught 4 marine mammal 4 marine mammals caught 1 Marine mammal dead 3 S 16 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E AO: Littoral zone of Gabon. 14 mortality cases on 193 (8 STW and 5 WHA) IO: Mozambic Channel and near to the Seychelles. One mortality case on 41 (WHA).

17 Indices of interactions between PSF and MAM meeting 1,% 1,% survival 1,%,1% meeting during fishing catch AO IO Spider graph (logarithmic scale) 17 Meeting= 1.3% Catch=.6% Meeting during fishing= 23% Survival= 99.7%

18 Discussion Environmental conditions that influence the distribution of co occurrence of activities and observations (Sequeira et al., 212; Saetre & Da Silva, 1984). Apparent low impact in the studied oceans (different from the Pacific, Hall, 1998) 18

19 Conclusions and perspectives Frequency distribution of co occurrence occurrence of activities and observations influenced by seasons and years Hotspots of interactions: coastal zone of Gabon, Mozambique channel (WHS and MAM) and Seychelles (MAM) Form to the attention of shipmasters Need to increase the percentage of coverage of scientific observers Descriptive models for the study of environmental factors Tagging experiment (ISSF) 19

20 2

21 21 Annexes

22 2 2 N N 1 Marine mammals 1 S 5S 1 2 S 2 activities.5 mammal/activity MAM 1 S 1 2 S.5 Whale sighting/activity WHA 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E N 2 N S 1 S small toothed whale/activity.1 Big toothed whale sighing/activity 2 S 2 S 22 STW BTW 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E 3 W 25 W 2 W 15 W 1 W 5 W 5 E 1 E 15 E

23 1 1 1 S 1 S 1 2 S MAM 1 2 S WHA 2 3 S 12 Activities.2 Marine mammal sighting/activity 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E 2.2 Whale sighting/activity 3 S 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E 1 1 S 1 1 S 1 2 S STW 1 2 S BTW 2.4 Small toothed whale sighting/activity 2.1 Big toothed whale sighting/activity 3 S 3 S 23 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E 3 E 35 E 4 E 45 E 5 E 55 E 6 E 65 E 7 E 75 E 8 E

24 .1.12 AO IO IO AO IO IO ghting/activity.6.8 ghting/activity.2.4 sig.2.4 sig years-seasons years-seasons.15 AO IO IO e-4 1e-3 AO IO IO ghting/activity 6e-4 ghting/activity.5 si 2e-4 4e-4 si years-seasons e+ years-seasons

25 MARINE MAMMALS WHALES meeting 1,% meeting 1,% 1,% 1,% 1,% 1,% survival,1% meeting during survival,1% fishing meeting during fishing AO IO AO IO catch catch SMALL TOOTHED WHALES meeting 1,% 1,% 1,% BIG TOOTHED WHALES meeting 1,% 1,% 1,%,1%,1% survival,1% 1% meeting during fishing survival,1% meeting during fishing AO IO AO IO catch catch

26 Species and fate (source observers) Tbl Table :Species S i and numbers of marine mammals encircled ldand dthi their fate ft in observers data on purse seine fishery in the Atlantic and Indian Ocean from 1995 to 211 Species/groups Common name Escaped from the net Released alive at sea Released dead at sea Other or Unknown Total Max on a AO IO Total AO IO Total AO IO Total AO IO Total AO IO Total catch Unidentified cetacean Unidentified baleen whale Megaptera novaeangliae (Humpback whale) Balaenoptera physalus (Fin whale) Balaenoptera edeni (Bryde's whale) Balaenoptera borealis (Sei whale) Unidentified toothed whale Tursiops truncatus (Common bottlenose dolphin) Stenella attenuata (Pantropical spotted dolphin) Peponocephala electra (Melon-headed whale) Steno bredanensis (Rough-toothed dolphin) Pseudorca crassidens (False killer whale) Globicephala melas (Long-finned pilot whale) Globicephala macrorhynchus (Short-finned pilot whale) Total general % 6% 68% 62% 32% 24% 31% 6% % 5% 2% 7% 3% 1% 1% 1% 26

27 Fate of marine mammals after being encircled by PSF (source observer data) Indian Atlantic Escaped from the net Released alive at sea Released dead at sea Other or Unknown 27

28 28 ObServedataset 1995 AVDTH dataset OA OI Total OA OI Total ACTIVITIES WSH % WSH by activities %.7%.11% SETS % SETS among activities 5.86% 54.21% 61.32% 53.99% 5.88% 5.35% 5.67% WHS associated itdto a set % WHS with sets 99.1% 93.48% 95.61% 98.1% 39.66% 32.43% 37.94% % SETS with whs 2.78% 1.67%.56% 1.98%.94%.39%.73% CATCHES occurancy of whs Nb WHS caught % WHS by catch occurancy 46.84% 45.33% 46.47% WHS fate known % survie 99.9% 97.44% 98.66%

29 AVDTH dataset ObServe dataset OA OI Total OA OI Total ACTIVITIES MAMMALS BALEINES GRAND ODONTOCETES PETITS ODONTOCETES %MAMMALS by activity 1.59% 6.7% 1.44% 2.28% 1.41% 1.16% 1.31% %WHALES by activity 1.47% 6.32% 1.34% 2.13%.89%.5%.73% %BIG TOOTHED by activity.%.1%.%.%.6%.4%.5% %SMALL TOOTHED by activity.12%.37%.9%.15%.47%.61%.53% SETS % SETS among activities 5.86% 54.21% 61.32% 53.99% 5.88% 5.35% 5.67% MAMMALS associated to a set WHALES BIG TOOTHED SMALL TOOTHED % MAM with sets 77.7% 78.3% 81.74% 85.61% 11.98% 7.99% 1.56% %whales 81.72% 99.82% 86.37% 82.69% 16.95% 16.52% 16.84% %BIG TOOTHED 33.33% 2.% 2.% 27.27% 6.93% 6.12% 6.67% 29 %SMALL TOOTHED 29.95% 1.1% 19.67% 21.3% 3.16% 1.14% 2.21% % SET with MAM 3.13% 12.35% 2.35% 4.23% 2.88% 1.73% 2.44% %set with whales 2.89% 11.66% 2.19% 3.94% 2.56% 1.55% 2.17% %set with big.1%.2%.%.1%.7%.5%.6% %set with small.24%.68%.15%.27%.25%.13%.2% CATCHES occurancy of mam CATCHES occurancy of whales CATCHES occurancy of big CATCHES occurancy of small Nb MAM caught Nb WHALES caught Nb BIG caught Nb SMALL caught % MAM by catch occurancy 3.3% 1.81% 2.77% %whales 3.72% 3.83% 3.75% %big.%.%.% %small 1.65%.28% 1.1% MAM dead whale dead ptit dead 9 9