Presentation is loading. Please wait.

Presentation is loading. Please wait.

Fisheries Oceanography. SST anomalies off Peru coastline.

Similar presentations


Presentation on theme: "Fisheries Oceanography. SST anomalies off Peru coastline."— Presentation transcript:

1 Fisheries Oceanography

2

3 SST anomalies off Peru coastline

4 ENSO impacts on pelagic fishes: variable catch reductions (Peru) A. Bertrand 0 4 8 12 19501960197019801990 Catch (M. tons) El Nino (Yánez et al. 1992)

5 Spatio-temporal scales of effects on peruvian pelagic fisheries A. Bertrand Time Space Decade Inter-annual MonthSeasonYearDay Ocean Local Regional Basin Stock condition before ENSO Adapted reproduction Fishery pressure Local Upwelling ENSO strength and duration Inter-decadal regime Large scale forcing Small scale forcing

6 Pacific Decadal Oscillations

7 ENSO and pelagic fisheries: regime shift Chavez et al. 2003

8 Clupeidae American shad Alosa sapidissima Engraulidae baelama anchovy Thryssa baelama

9 (Chavez et al. 2002) A. Bertrand

10 (Chavez et al. 2002) A. Bertrand

11 Pacific Decadal Oscillation Warm PhaseCool Phase Wintertime Wind (arrows) and Sea SurfaceTemp (colors) - Affect the N. Pacific, with secondary signatures in the tropics (opposite for ENSO)

12 Pacific Decadal Oscillation (PCA of N. Pacific SST) 20-30 year duration

13 A. Bertrand Chavez et al 2003

14 A. Bertrand Chavez et al 2003

15 Humans as Top Predator

16 Production ( million tonnes) 50 100 180018401880192019602000 Year EEZs Claims Global Trend in Landings

17 (Pauly et al., 2002) Non-registered catches Expansion of fisheries A. Bertrand

18 (Pauly et al., 2002) Non-registered catches Expansion of fisheries A. Bertrand

19 Trawling

20

21 Humans as “engineer species” Trawling disrupts sea bottom…… Trawling ecosystem effects: –Decrease of spatial complexity –Decrease of target and bycatch species –Increase of scavenger species –Overall loss of biodiversity (macro- organism level)

22

23

24 TrawledUn-trawled

25 Trawled AreaUn-trawled Area (bottom sonar images) Trawling Impact

26 Bycatch of unwanted species

27 Turtle Excluder Device (TED)

28 Trawling frequency by german vessels between 1993 & 1996 (Rijnsdorp 1997) P. Cury

29 Marine Protected Areas No Trawling Area Gulf of Maine

30 Gillnetting

31 Bycatch of unwanted species

32 (Pauly et al., 2002) Non-registered catches Expansion of fisheries A. Bertrand

33 Purse seining

34 Schooling behavior

35

36

37

38

39

40

41

42 Bycatch of unwanted species

43 (Pauly et al., 2002) Non-registered catches Expansion of fisheries A. Bertrand

44 Longlining

45 Bycatch of unwanted species

46 (Pauly et al., 2002) Non-registered catches Expansion of fisheries A. Bertrand Why steady increase?

47 Catches per 100 hooks (Japanese fleet) 1952 1964 1958 1980 Myers & Worm, 2003

48 Shark Populations NE Atlantic Baum et al. 2003

49 Fishing Down the Food Web

50 Fishery induced changes in world fish composition

51 Compensation in exploited fish communities (Tropical Atlantic) Myers & Worm, 2003 ● Blue Marlin △ Sailfish ○ Swordfish

52 Compensation in exploited fish communities (Southern Grand Banks) Myers & Worm, 2003 ● Codfishes (Gadidae) ○ Flatfishes (Pleuronectidae)

53 Seafood consumption (US)


Download ppt "Fisheries Oceanography. SST anomalies off Peru coastline."

Similar presentations


Ads by Google