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Biodiversity of Fishes: Recent Trends in Global Fisheries Rainer Froese GEOMAR Kiel, Germany 24.01.2013.

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Presentation on theme: "Biodiversity of Fishes: Recent Trends in Global Fisheries Rainer Froese GEOMAR Kiel, Germany 24.01.2013."— Presentation transcript:

1 Biodiversity of Fishes: Recent Trends in Global Fisheries Rainer Froese GEOMAR Kiel, Germany 24.01.2013

2 I gratefully acknowledge permission to use slides from Daniel Pauly, Boris Worm, Ram Myers, and Villy Christensen

3 Overview The status of global fisheries Ecosystem impacts of fisheries Causes for overfishing Possible solutions

4 The Status of Global Fisheries

5 150 Years of Newfoundland Cod Fishery

6 A typical Fishery.. Froese and Kesner-Reyes, ICES 2002

7 Maximum catch and MSY are related Froese et al. 2013

8 Trends in Global Fisheries ? Froese and Kesner-Reyes, ICES 2002

9 Out of Current Stocks in 2048 ? Worm et al., Science 2006 Stocks (%) 2048 ?

10 More & More Collapsed stocks Froese et al. 2013

11 Out of New Stocks in 2020 Froese et al. 2008, Marine Policy

12 Froese et al. 2012, Marine Biology Reality Check in 2012

13 Where Do Most of the Catches Come From? 0

14 China grossly over-reported its marine fisheries catches throughout the 1990s … (Watson & Pauly, Nature, 2001).

15 Impact of Over-reporting on Global Catch Statistics Watson and Pauly (Nature), 2001.

16 (t/km 2 ) Biomass of Table Fish in 1900 Christensen et al. 2003

17 and in 2000…. Christensen et al. 2003

18 Catch per 100 Hooks 1952 - 1980 Blue Marlin Swordfish Bluefin Tuna Dolphinfish

19 Source: Myers and Worm 2003. Nature 423: 280-283

20 Source: Myers and Worm 2003. Nature 423: 280-283

21 Source: Myers and Worm 2003. Nature 423: 280-283

22 Source: Myers and Worm 2003. Nature 423: 280-283

23 Source: Myers and Worm 2003. Nature 423: 280-283

24 Source: Myers and Worm 2003. Nature 423: 280-283

25 Source: Myers and Worm 2003. Nature 423: 280-283

26 Source: Myers and Worm 2003. Nature 423: 280-283

27 Source: Myers and Worm 2003. Nature 423: 280-283

28 Source: Myers and Worm 2003. Nature 423: 280-283

29 Source: Myers and Worm 2003. Nature 423: 280-283

30 Source: Myers and Worm 2003. Nature 423: 280-283

31 Source: Myers and Worm 2003. Nature 423: 280-283

32 Source: Myers and Worm 2003. Nature 423: 280-283

33 Source: Myers and Worm 2003. Nature 423: 280-283

34 Source: Myers and Worm 2003. Nature 423: 280-283

35 Source: Myers and Worm 2003. Nature 423: 280-283

36 Source: Myers and Worm 2003. Nature 423: 280-283

37 Source: Myers and Worm 2003. Nature 423: 280-283

38 Source: Myers and Worm 2003. Nature 423: 280-283

39 Source: Myers and Worm 2003. Nature 423: 280-283

40 Source: Myers and Worm 2003. Nature 423: 280-283

41 Source: Myers and Worm 2003. Nature 423: 280-283

42 Source: Myers and Worm 2003. Nature 423: 280-283

43 Source: Myers and Worm 2003. Nature 423: 280-283

44 Source: Myers and Worm 2003. Nature 423: 280-283

45 Source: Myers and Worm 2003. Nature 423: 280-283

46 Source: Myers and Worm 2003. Nature 423: 280-283

47 Source: Myers and Worm 2003. Nature 423: 280-283

48 Overfishing in the North Atlantic Trends from ‘Working Group’ reports by fisheries scientists in government agencies (NMFS, DFO, DIFMAR, IFREMER, etc.), compiled by R. A. Myers.

49 Fig. 1. Time series of biomass B relative to the biomass B msy capable of producing maximum sustainable yield, for 54 stocks of the Northeast Atlantic. B pa is the biomass below which the reproductive capacity of the stock may be reduced. The arrow indicates the trajectory if 75% of the stocks were to reach B msy by the internationally agreed deadline of 2015. Froese & Proelss 2010, Fish & Fisheries Overfishing in Europe

50 Fig. 2. Time series of fishing mortality F relative to the fishing mortality F msy associated with maximum sustainable yield, for 54 fish stocks of the Northeast Atlantic. If F is larger than the intrinsic rate of population increase r max, stocks will shrink below safe biological levels. The arrow indicates the trajectory if 75% of the stocks were to reach F msy at the internationally agreed deadline of 2015. Overfishing in Europe Froese & Proelss 2010, Fish & Fisheries

51 Fig. 3. Time to reach the biomass B msy capable of producing maximum sustainable yield, for 54 fish stocks of the Northeast Atlantic. B pa is the biomass below which the reproductive capacity of the stock may be reduced. Stocks in the green box have reached the target, stocks in the yellow box may reach B msy in 2015 if fishing is halted in 2010. Stocks in the red box are unlikely to reach B msy until 2015. Overfishing in Europe Froese & Proelss 2010, Fish & Fisheries

52 In Summary Global fisheries have drastically reduced the size of their target stocks, typically by 90% since 1950.

53 Ecosystem Impacts of Fisheries

54 Impact on the Sea Floor Photos: Dr. K. Sainsbury, CSIRO before after

55 Area in NZ accessed by Scallop Trawlers Before

56 Immediately after first trawling Area in NZ accessed by Scallop Trawlers

57 Three years later (Dayton 1998) Area in NZ accessed by Scallop Trawlers

58 Tracks of Trawls courtesy F. Grassle

59 Shrimp Trawlers from Space QuickBird satellite on 20 February 2003, off the coast of Jiangsu province near the mouth of the Yangtze River;

60 And More Trawling for Shrimps…

61 Not only in China, also in Texas Photo courtesy of Dr. Kyle van Houten (Duke University) Here: shrimp trawlers off the Texas Coast, Gulf of Mexico

62 Ecosystem Effects of Fishing Trophic level Phytoplankton Top predators Prey fish Zooplankton................... *.......... *.*. *.*.......  10% *. 4 3 2 1

63 Pauly et al. (Science, 1998) Marine Freshwater Fishing Down Food Webs

64

65 Fisheries-induced Unnatural Selection Fishing removes large, old, highly fecund, ‘fit’ fishes before they can reproduce Reductions in size and age at first maturity are visible in most stocks Stocks adapted to fishing become less well adapted to their natural environment Recovery will take long, leaving a ‘Darwinian debt’ to future fishers and consumers Diekmann et al. 2009, ICES Insight

66 In Summary… Global fisheries have severe negative impact on the marine ecosystem

67 Causes for Overfishing Crash course in fisheries management –Three types of overfishing

68 Fisheries Management Basics MSY Cost of fishing € €€€€ MEY F pa ? F lim † Economic overfishing Growth overfishing Recruitment overfishing

69 EU Fisheries Management MSY Cost of fishing € €€€€ MEY ? F lim † Subsidies

70 Causes for Overfishing Crash course in fisheries management –Three types of overfishing –Subsidies increase overfishing –Overfishing decreases mean size of fish

71 Catching Baby Fish

72 Causes for Overfishing Mismanagement Subsidies Misinformation

73 The Fecundity Myth “In theory, one pair of cod is enough to replenish the North Sea cod stock…” Fact 1: No relationship between fecundity and reproductive success

74 No Relationship between Fecundity and Reproductive Success Froese and Luna, ACTA 2004

75 The Fecundity Myth “In theory, one pair of cod is enough to replenish the North Sea cod stock…” Fact 1: No relationship between fecundity and reproductive success Fact 2: ICES estimates critical spawning stock biomass for North Sea cod at 70,000 t (10 million pairs…)

76 The ‘Juveniles Die Anyway’ Myth “Catching juveniles is good because it let’s the old, productive fish live. Many juveniles would have died anyway.” Facts: 1.Causes for mortality do not substituted, they add up. 2.Juveniles are the adults of tomorrow. 3.A given catch kills 10 times more juveniles than adults.

77 Possible Solutions

78 Solution: Reduce Reduction Eat Anchovies, Sardines, Mackerels…

79 Solution: MPAs Wood et al. (submitted) WPC: World Park Congress CBD: Convention on Biological Diversity

80 Solution: Stop Subsidies Khan et al. (2006)

81 Solution: Work With Consumers and Retailers Fish Rulers Fisch im Handy Marine Stewardship Council Sonderwirtschaftszone westliche Ostsee More Research

82 Harvest Control Rules Froese et al. 2011

83 Preventing Collapse of North Sea Herring

84 Conclusions Fish stocks are declining worldwide Overfishing is drastically changing the marine ecosystems Overfishing is driven by mismanagement, myths and subsidies Top down solutions (MPAs, no subsidies, better management (HCR)) are needed but slow Involving retailers and the public seems most promising

85 Exercise Go to www.ices.dk, Latest Avicewww.ices.dk For herring, cod, or plaice: Which stock is of sufficient size (B > Bmsy) and fished sustainably (F < Fmsy)? Note: use 2 * Bmsy-Trigger (or 2 * Bpa) as proxy for Bmsy. Ignore stocks where Fmsy is not known.


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