Humans and the Sea -- Fisheries, management, and sampling Millions of people depend on fisheries… in what ways? Food 86

1. Humans and the Sea -- Fisheries, management, and sampling Millions of people depend on fisheries… in what ways? Food 86 million tons/year Jobs Products & materials Recreation & entertainment Sport fishing Diving & tourism Aquarium trade

2. Lots of people in the world… and, like other natural predator/prey relationships, we take advantage and harvest many marine organisms …thus, competition for resources Marine ecosystems provide over 30% of worldwide animal protein consumption Fig. 17.2 • How much is this?

3. Are these levels sustainable? How do we prevent overfishing? • Depends on what, where, and current practices

4. …stresses on fisheries What is the 2010 demand for fish? 10-40 million tons above production Cultural practices, consumption, etc., varies worldwide E.g. average fish consumption/person/year Japan = 37.7 lbs U.S. = 16.6 lbs

5. Where are the richest fishing grounds? • Areas of upwelling, bordering continental shelf where primary production is higher • Most of the largest takes are around industrial nations • Exploited for the longest time • Most fishing grounds in Atlantic, Pacific, Mediterranean are in decline or exhausted Why and How is this happening? Fig. 17.4

6. Gill net: Northeast and worldwide panel of webbing of clear monofilament line; can be set at any depth; fish can’t see the net, so they swim right into it and are caught. Lots of bycatch (“junk”/non-target) -- animals that are too large to pass through the webbing (mammals, turtles, etc.) Purse seines: Vertical, weighted net encircling aggregates; pulls bottom closed (drawstring) preventing fish from swimming down Unintended bycatch; i.e. dolphin, sharks, sea turtles Hook and line, and long-line: Commercial rigs can setup miles of unselective longlines (lots of bycatch) hard to be selective with this gear…but, possible. E.g., choosing bait, jigs, lures, and hook sizes known to catch their target species. Trawls / Bottom trawl: single most important fishing method in the Northeast produces the most noticeable bycatch problem & demolishes the environment bottom trawl is a funnel-shaped net that is dragged on the bottom of the sea Mortality: damaged in the net, brought up from the depths too quickly, or thrown back too late. Fig. 17.6

7. What are the most important fish? Schooling fish Herring, sardines, anchovies… Over continental shelf & upwelling areas Caught by purse seines Demersal cold-water fish Cod, pollock, haddock… E.g. Alaska pollock is largest fishery of U.S. Caught by trawls Over exploited; closed many fisheries in the last decade Open-ocean fish Tuna (skipjack, yellowfin, albacore, bigeye, bluefin) Caught by seines, longlines, and gill nets

8. Can we use methods that are more sustainable and environmentally responsible? Harpooning Harpooners catch large, pelagic predators such as bluefin tuna and swordfish. Hook and Line Hook and liners target a variety of fish, ranging from open ocean swimmers, like tuna and mahi mahi, to bottom dwellers, like cod Trolling Trollers catch fish that will follow a moving lure or bait, such as salmon, mahi mahi and albacore tuna.

9. Policies, regulations, & enforcement Balance between population size, natural mortality, and fisheries Sustainable? # of fish caught ≤ # fish reproduced Use sustainable fishing methods (globally, change our ways) to prevent population / fisheries collapse Fig. 17.10

10. Example of sustainable commercial fishery • http://www.youtube.com/watch?v=i5mMI8t7vV0&feature=related

11. Research and Restoration provides evidence/data to inform regulations

12. “spaghetti” tags • Archival tags • Satellite tags • Acoustic telemetry

13. Mariculture / Aquaculture Farming Open vs. closed Pros vs. Cons High production at expense to environment; ie, wild populations, disease, pollution, etc. Use of genetics & biotech Faster growth, disease resistance, etc. Salmon, shrimp Local sustainable mariculture www.carlsbadaquafarm.com Local restoration projects http://www.pier.org Fig. 17.12

14. Human Impacts – our role, impacts, and responsibilities Habitat destruction Fisheries Resource management Recreation Aquaculture Pollution Coastal runoff Sewage Oil Introduced species Invasive / pest species What can we do instead? MPA Marine Protected Areas Know our impacts and respect that we are just one species of nature Be an informed consumer Reduce, reuse, recycle