Can we get more fish? Degradation and recovery of fisheries - PowerPoint PPT Presentation

International Conference on Science and Technology for Sustainability 2009: Global Food Security and Sustainability during 9:10-9:50, on September 18, 2009 Can we get more fish? Degradation and recovery of fisheries resources Degradation and recovery of fisheries resources. 松田裕之 Hiroyuki Matsuda Yokohama National University COE Eco-Risk Asia Program Leader Pew Marine Conservation Fellow 2007 Pew Marine Conservation Fellow 2007 Special thanks to: Drs. J. C. Castilla, Y. Hiyama, H. Ijima, T. Katsukawa, Y. Katsukawa, C. Kikuchi, M. Makino, T. Obara, M. 1 Williams, B. Worm, A. Yatsu,

My 11 recommendations 1. Do not eat high value fish too much! 2. Catch more fish at lower trophic levels; 3. 3 D Do not use too much fish as fish meal; t t h fi h fi h l 4. Reduce discards before and after landings; 5 5. Establish food markets for temporally fluctuating fishes at Establish food markets for temporally fluctuating fishes at lower trophic levels; 6. Improve the food-processing technology used on small pelagic fishes; pelagic fishes; 7. Switch the target fish to correspond to the temporally dominant species; p 8. Conserve immature fish especially when the species is at a low stock level; 9. 9 Conserve both fish and fishers; Conserve both fish and fishers; 10. Say goodbye to traditional MSY theory; 11. Monitor not only the target stock level but also any other y g y indicator of the “ entire ” ecosystem. 2

1 Do not eat high value fish too much! 1. Do not eat high value fish too much! 3

4 4 Are the oceans dying? Newsweek 2003 7 14 Newsweek 2003.7.14 2002/6/21

R. A. Myers & B. Worm (2003) Rapid worldwide depletion of predatory fish communities Boris late Ransom Worm Myers … We conclude that declines of large predators that initially occurred in predators that initially occurred in coastal regions, have extended throughout the global ocean, with potentially large consequences on 5 ecosystems. Nature 423:280-283 (2003)

Fortune Magazine Names Ransom Myers on of World ’ s top ten to ld ’ f watch BorisWorm Reykjavik June 2006 photo by Matsuda RansomMyers Meryl Williams Meryl Williams 6 http://as01.ucis.dal.ca/ramweb/

Even if the past reduction rate continues, SBT will not go extinct within 50 years not high will not go extinct within 50 years, not high extinction risk in the immediate future. ⎡ ⎤ − + − 2 ( x x ) ( x r * t x ) 1000) = − 100,000 0 c 0 c ⎢ ⎥ G ( t ) exp σ 2 2 πσ πσ ⎣ ⎣ ⎦ ⎦ 2 t 2 3 2 t t size ( × 1 推 10,000 ⎡ + ∞ ⎤ 定 ∑ ∑ σ = σ ρ τ 2 2 1 2 ( ) 親 ⎢ ⎢ ⎥ ⎥ r ⎣ ⎣ ⎦ ⎦ 魚 魚 1,000 1 000 pulation τ = 1 尾 (Lande & Orzack 1988) 数 100 （ mated pop 千 千 尾 10 ） Estim 1 1970 1990 2010 2030 2050 2070 西暦年 (M t (Matsuda et al. 1996) d t l 1996) 7 Photo by Fisheries Research Agency, Japan

Is the ocean really dying? � The total catch decreased in northwest Atlantic. � It is increasing in western central Pacific. 8 （ FAO, SOFIA2006)

Meryl Williams (CoML member) invited talk “ Marine ecosystem services and fishing: agreements and disagreements between fisheries scientists and Counter view 1: Spatial Methods Counter-view 1: Spatial Methods ecologists ” October 21, 2009, Yokohama, 5th World Fisheries Congress Walters Can J Fish Aquat Sc 2003 Walters Can J Fish Aquat Sc 2003 Atlantic Ocean Pacific Ocean Pacific Ocean Indian Ocean Data: Japanese longline p g - Interpolated line - Myers & Worm method - Mean catch rate, fished cells 9

Rebuilding Global Fisheries (Worm et al. 2009) Trends of biomass ( B ) & Current exploitation rate exploitation rate ( u ) for p ( ) versus biomass for 166 166 individual stocks. individual stocks. 10 Boris Worm

2 Catch more fish at lower trophic levels; 2. Catch more fish at lower trophic levels; � Biomass of lower trophic levels is much larger than biomass of top predators. p p Food web pyramid human Marine mammals mammals tunas sardine zooplankton phytoplankton p y p 11

Fishing down (MA 2005) by Daniel Pauly g ( ) y y ? � Mean Trophic Le el is calc lated from FAO � Mean Trophic Level is calculated from FAO FISHSTAT and FISHBASE � MTL depends on stock fluctuation of sardine � MTL depends on stock fluctuation of sardine and anchovy, rather than overfising. 12 By D.Pauly

Fishing down in China Fishing down in China 13 Change in China ’ s Marine Trophic Index over the Years (from Xu et al. 2009) (Source China ’ s Fourth National Report)

Ijima, Katsukawa, Matsuda 14 Unpublished data No fishing down in Japan

We can use >2 million tons of pelagic fishes sustainably in Japanese EEZ. Source: Fisheries Research Agency Japan Source: Fisheries Research Agency, Japan 15

New Zealand imports p Pacific saury (samma) 16 http://kaiseki.ori.u-tokyo.ac.jp/~katukawa/blog/2008/07/post_378.html

Developed countries people eat high value fishes, Developing countries people eat low value fishes Developing countries people eat low value fishes. After Doug Beard From Delgado et. al. 2002, Fish to 2020, Table E.14 17 From Delgado et. al. 2002, Fish to 2020, Table 3.3

Percentage of Seafood as the source of Animal Protein Fisheries products Fisheries products are more important as food than other areas (Food Security). 18 Data Source: FAO Food Balance Sheet

My typical lunch menu My typical lunch menu (for 2 persons) 650 650 yen (US$6) with coffee 650 yen (US$6) with coffee 650 (US$6) (US$6) ith ith ff ff 19 2006/5/22 19 21

3 Do not use too much fish as fish meal; 3. Do not use too much fish as fish meal; � 7 kg of sardine make ca. 1 kg of yellowtail in aquaculture. q � 20 kg of chub mackerel make ca. 1kg of tuna in fish farm in fish farm � To eat sardine or mackerel is more environmentally friendly than to eat tuna. Beyond beef – Jeremy Rifkin: Beyond beef – Jeremy Rifkin: Feed cows on grass, not corns ( “ Beyond f ” ) B Beef ) 20

4 Reduce discards before and after landings; 4. Reduce discards before and after landings; “ Discard ” in academic meeting (SOFIA 2006) 21

5. Establish food markets for temporally fluctuating fishes at lower trophic levels; � “We can still get many fish such as Pacific saury and jack mackerel in Japanese waters. We should eat fish that is temporally abundant by a variety of cooking methods. Do not decide dinner menu (e.g. fried mackerel) before coming to fish market. Think fish and its cooking method after seeing fishes in the market.” (K. Ikuta at Tsukiji fish market) 22 http://www.uogashiyarou.co.jp/

Species Replacement of Pelagic Fishes Species Replacement of Pelagic Fishes Anchovy mt) Horse mackerels Horse mackerels (1000 m Pacific saury Chub mackerel Sardine Sardine Japan ( Catch in C 23

Landings of small pelagic fish Landings of small pelagic fish fluctuate from species to species. anchoveta anchoveta sardine chub mackerel Atlantic herring Atlantic herring 24 http://www.fao.org/WAICENT/FAOINFO/FISHERY/publ/sofia/fig4e.asp

6. Improve the food-processing technology used on low value fishes; 25

7. Switch the target fish to correspond to the temporally dominant species; t th t ll d i t i (Katsukawa & Matsuda, Fish.Res. 2002) Policy 1 (no switching; NSF) Fishing effort E i = e i /3 (constant) Or E i = E i ( x i ) (independent of x j ) O E E ( ) (i d d f ) Policy 2 (switching; SF) Policy 2 (switching; SF) E i = e i x i /( Σ x i ) (∝stock abundance) Fishers focus on relatively abundant fish species. b d t fi h i 26

Switching increases & stabilizes total catch, save it at low levels No Switching Switching 0.5 0.5 0.4 0.4 0 3 0.3 0 3 0.3 Catch Catch 0.2 0.2 0.1 0.1 0 0 900 910 920 930 940 950 960 970 980 990 900 910 920 930 940 950 960 970 980 990 Time Time Time Time � If stock fluctuations of alternative fish are negatively correlated or independent negatively correlated or independent 27 http://kaiseki1.ori.u-tokyo.ac.jp/~katukawa/blog/blosxom.cgi/study/article/switching.wikieditish

8. Conserve immature fish especially when the species is at a low stock level; hen the species is at a lo stock le el; 1970s 1980s 1990s 1993- %immatures 65.0% 60.0% 87.0% 90.6% 28

Large fluctuation of recruitment Large fluctuation of recruitment Var[recruitment] ： 80s ＞ 90s, P <0.3% Var[RPS] ： 80s ＜ 90s P <10 -7 Var[RPS] ： 80s ＜ 90s, P <10 -7 Strong year classes Strong year classes appeared twice 29

http://www.ices.dk/marineworld/fishmap/ices/pdf/mackerel.pdf O Overfishing in chub mackerel immature fish! fi hi i h b k l i t fi h! Chub mackerel fisheries Norway = Individual Quota Japan = Dirby competition Age composition of chub Age composition of chub mackerel landings North Atlantic 2000-2004 Japan 1970 Japan 1995 30

Quiz Quiz Which is Pacific chub mackerel? � Recently, Japan import Atlantic chub mackerel. Japanese often eat Atlantic chub mackerel than Pacific chub mackerel. ① ② 31 Photos, see Matsuda (2009, Bun-ichi, Tokyo)