What are the threats to the oceans? Consequences. Four examples. Tuna

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1 Conservation of the marine environment Dr. Katrina Mangin Department of Ecology and Evolutionary Biology What are the threats to the oceans? Over-fishing & over-harvesting Climate Change (seas are warming) Coastal development and habitat loss Runoff from land (fertilizers, oil, sediment) Pollution, fertilizer, and garbage in sea Invasive species Consequences Loss of biodiversity Food source threatened Human health risks Mercury in fish (power plants) Swimming in dirty water (fertilizers) Loss of fresh water on islands (SW intrusion, pollution) Habitat destruction/loss 50% US population lives on coast (development) Coral reefs dying (global warming) Ocean floor destroyed (trawling) 150 dead zones in 2004, double since 1990 (UN data)( fertilizers) Four examples Tuna fishery (dolphins, overfishing, mercury) Worldwide decline in all predatory fish Gulf of California -shrimp fishery Gulf of California - working with fishermen Tuna Lion steak Eagle Pie A top predator in ocean Many species, worldwide Long migrations Warm blooded! Up to 14 feet long 1

2 Tokyo fish market 5 million pounds of seafood per day 400 different types of seafood Imports from 60 countries on 6 continents 2

3 Tuna auction 3

4 Tuna is the most traded fishery in the world 3 million tons of catch per year $3 billion per year globally Europe and US top buyers for canned tuna fresh/frozen tuna market increasing worldwide (sushi more popular than ever) $65-$85 per kg fresh tuna - whole sale 1038 lbs x $85 = $88,230 The tuna dolphin controversy 7 million dolphins were killed by tuna fishing starting in late 1950s How? Nets set on dolphins to catch tuna Fresh bluefin can go for almost $500 per lb 4

5 Some terms Bycatch - incidental catch of non-targeted species Dolphin set - setting nets around dolphins in order to catch tuna Floating Object Set or Log Set - setting nets around floating objects in order to catch tuna Purse seine nets & dolphin sets - dolphin safe tuna label appears Tuna follow dolphins 1980s: US tuna fleet can not encircle dolphins US embargo against other countries: no dolphin setting on tuna 1990: label on tuna cans 1. Dolphin-set fishing 2. School-set fishing Medina panels on nets Backdown to lower nets 3. Log-set fishing 5

6 International Tropical Tuna Commission (Eastern Pacific Ocean) Bycatch from tuna fishing for 2004 Type of "set" Animals Killed dolphin set floating object set Other Total marine mammals dorado wahoo salmon yellowtail other large fish trigger fish other small fish sharks and rays sea turtles unidentified fish other fauna Total 6, ,259, , ,310, Dolphin safe tuna Mexico protested embargo: product is not environmentally harmful International Tropical Tuna Commission (Eastern Pacific Ocean) US court case in don t weaken label Dolphin safe tuna? By far, worldwide most tuna fishing is still done with dolphin sets. US has many fewer tuna fleets than before In EU, no dolphin safe labels are required. Northern bluefin tuna Northern bluefin tuna: cross Pacific migrations Caught and tagged one juv. off Ca coast Northern bluefin tuna Western N. Atlantic 1) Aug 2002-Feb foraging 2) Summer, fall, and winter foraging in open ocean?? 3) February June 2004 captured off Japan - early spawning? Still considered a sustainable fishery by US govt. $180,000 for one bluefin (1000 lbs) 6

7 Southern bluefin tuna Longline fishing Longline-fishing, critically endangered, 500 individuals by 2105 Fishing methods Purse seine (dolphin sets, log sets) Long-line (miles of hooks at surface, depth or on bottom) Jigging (bunches of hooks) - smaller scale Fishing methods: disadvantages Purse seine Long-line Jigging Kills dolphins/ bycatch Tons of bycatch Small scale Bluefin tuna farming - a solution or a new problem? 1000 lbs and up per fish 20 tons of wild fish for one ton of fattened tuna Highly profitable, spain, croatia, australia, portugal One more way to overfish a depleted species 7

8 Biomagnification Top of food chain - accumulates toxins Sources of mercury? Power plants (coal fired) Garbage Photographic Processing Rapid worldwide decline of predator fish communities, Myers R.A. & B. Worm, Nature v. 423, 15May2003 What they concluded: Only 10% of large, predatory fish are left in the world s oceans. Black=bigeye Yellow=yellowfin Blue= bluefin Green=albacore White=billfish Decline in all oceans 1950s-2000 (Myers & Worm 2003) 8

9 Shrimp fishery For each pound of shrimp, ten pounds of bycatch * Scraping of ocean floor by trawling kills everything * bycatch= incidental catch that is thrown away Trawling for shrimp Florida shrimp trawler, Shrimp farming Ecuador Working with the fishermen Murex fishery in Gulf of California % wetlands converted to shrimp farms NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team 9

10 Black Murex (Hexaplex(muricanthus) nigritus) Larval settlement in the marine environment is not random. Commerical divers in Puerto Penasco, Sonora, Mexico. These divers collect murex snails in the summer, along with several other species. Settlement cues include chemicals, light, dark, depth, and substrate type. Shifting Baselines Swordfish, 1940, coastal Peru antiquefishingreels.com/ What can we do? Stop over-fishing! Support efforts to stop CO2 emissions Regulate fishing & coastal development Identify threats & culprits in local areas Document loss of marine habitat and diversity Establish marine reserves 10

11 What can we do, continued Involve all stakeholders in the solutions Educate next generation so that they care Support conservation efforts with your $$ and votes 11