Marine Resources Biological

Initial Questions What proportion of the protein in the human diet comes from the ocean? Where are commercially important fish found, and why? What fish group accounts for the largest commercial harvest? What is a reduction fishery? How much of the commercial worldwide fish catch is used for reduction?

How much seafood do we eat? Seafood makes up only about 4% of what people eat (on average) Seafood accounts for about 18% of the protein we eat 15% directly 3% indirectly through fish meal and livestock feed Varies by nation and culture Some small island nations – 50% of protein is from seafood 89% of the wild fish caught comes from the oceans

Where do we get fish? Two basic categories: Groundfish – live on or near the sea bottom (also called “demersal”) Pelagic – open ocean, upper water column Found predominantly in two places: The waters of the Continental Shelves Few offshore regions with abundant upwelling Largest commercial crop from Order Clupeiformes Herring, sardines and anchovies Most used for fish meal and fed to poultry and livestock

What is a Continental Shelf? Cod Wars video Cod Wars video (6:08)

More on Continental Shelf

What is upwelling? An oceanographic phenomenon involving wind that brings cool, nutrient-rich deep ocean water to the surface to replace warmer, nutrient-depleted surface water.

Upwelling Regions Five major coastal currents associated with upwelling areas Canary Current – off NW Africa Benguela Current – off southern Africa Califorina Current – off California and Oregon Humbolt Current – off Peru and Chile Somali Current – off Somalia and Oman

What is a reduction fishery? A reduction fishery is one that catches fish for purposes other than direct human consumption Fish oil Fish meal (for animal feeds for livestock – higher in protein than soy) Predominantly “forage fish” – small, short-lived, pelagic (mid-water) species like Atlantic menhaden, anchoveta, Japanese pilchard and others Currently accounts for about 25% to 33% of the world commercial catch

State of World’s Fisheries A Bleak Picture

Initial Questions What is maximum sustainable yield? – how does the concept relate to the concept of overfishing? What is the current condition of the world’s fisheries?

Until the 20 th century people believed that the sea was an infinite resource Maximum sustainable yield is the greatest yield (catch) of a target species that fisheries can take without jeopardizing future catches. Overfishing occurs when the amount of fish taken exceeds the maximum sustainable yield Studies have shown that the world’s fisheries cannot sustain the present catch levels Maximum sustainable yield

Problems with overfishing Several fisheries show the consequences of overfishing Newfoundland cod North Atlantic swordfish Most valuable fish today – selling for $100/kg in Japan Many fisheries scientists believe this fish is doomed to extinction New Zealand’s orange roughy Pantagonian toothfish (aka Chilean seabass) By-catch Unintentional capture of organisms Estimates suggest that 25% of the worldwide fish catch is bycatch

What has changed since WWII? Big increases in effective fishing effort since WWII Increases in vessel numbers and sizes Rapid technological advances Industrial-scale fishing Trawling, purse seining, long-lining Small-scale or artisanal Shallow tropical waters for food fish and shrimp Compete with industrial-scale shrimp trawlers

Global Levels of Exploitation

Fishing stocks by MSY

Fishing Down the Food Web For a rebuttal, see Ray Hilborn’s blog and seafood news.comRay Hilborn’s blogseafood news.com Daniel Pauly: The ocean’s shifting baseline Daniel Pauly: The ocean’s shifting baseline (TED Talk – 8:58)

Commercial Fishing Methods Five primary methods

Initial Questions What are the five primary methods used in commercial fishing? How is it that the fishing industry seems to thrive despite estimates that the annual fish catch sells for less than it costs to catch the fish?

Gillnetting Vertical panels of netting normally set in a straight line Fish caught in several ways Wedged – held by the mesh around the body Gilled – held by mesh slipping behind opercula Tangled – held by entangling net in fish spines, teeth, etc. Several types Set gillnets Drift Encircling gillnets Combined gillnets-trammel nets Gill netting on the Miles RGill netting on the Miles R. (5:26)

Drift Netting Nets set on floats that drift below the surface Older (pre-1960s) nets had larger mesh and could be as long as 50 miles In 1987 the US restricted the length of nets to 1.5 nautical miles (1.7 statute miles) By-catch problems

Longlining Consist of long line with many branch lines (aka “snoods” or “gangions”) Can be set on the surface ( pelagic ) or on the bottom ( demersal ) Commonly target Pelagic - swordfish, tuna Groundfish - halibut, cod sablefish and other species By-catch problems LongliningLonglining (9:33)

Purse seining A seine is a fishing net that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats Purse seines have rings along the bottom of the net that can draw the bottom closed. Commonly targets fish that school, like sardines, mackerel, anchovies, herring, and some species of tuna By-catch problems Purse seining in AK Purse seining in AK (3:39)

Trawling A method of fishing that involves pulling a fishing net though the water behind one or more boats – the net is called a trawl Can be used on the bottom (“bottom trawling”) Cod, squid, halibut and rockfish Can be used in the water column (“midwater trawling” or “pelagic trawling”) Anchovies, shrimp, tuna and mackerel Trawl commercial 1 Trawl commercial 1 (1:54) Trawl commercial 2 Trawl commercial 2 (1:13)

How do fisheries survive – economically? According to estimates, the world’s fishing fleets spend about $54 billion to catch $70 billion in fish Fisheries survive because of government subsidies Grants Low- or no-interest loans Free or low cost fuel Tax incentives Price controls

Protecting sustainable ocean resources

Sustainable seafood? Let’s get smart TED TalkTED Talk (9:26)