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Fisheries. Traditional food production and distribution practices are unable to feed the world’s 6.3+ billion people Will resources in the sea be able to provide enough food to alleviate future problems of malnutrition and starvation ?.

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  • Traditional food production and distribution practices are unable to feed the world’s 6.3+ billion people

  • Will resources in the sea be able to provide enough food to alleviate future problems of malnutrition and starvation ?

  • Most valuable living marine resources:

  • Demersal fish

  • Pelagic fish

  • Crustaceans

  • Mollusks

  • Marine mammals

Location of the world’s major commercial fisheries

coastal areas


  • Commercial fishing:

  • 500 species regularly caught

  • Employs 200 million people worldwide

  • In 2002 the world fishing fleet numbered about four million vessels.

  • In 2005:

  • 100 million tons taken

  • $70 billion

Global Fish Catch

World Commercial Catch of Marine Fishes, Crustaceans, and Mollusks (1995)


Species Group Millions of Metric Tons, Live Wt.

Herrings, sardines, anchovies22.0

Jacks, mullets, sauries11.2


Cods, hake, haddock10.6

Redfish, basses, conger eels 7.0

Crustaceans 4.8

Tunas, bonitos, billfish 4.7

Mackerel, snooks, cutlass fishes 4.7

Flounders, halibut, soles 0.9

Miscellaneous marine fishes17.7

Total (excluding marine mammals)94.6

Food & Non-Food Products

from the Sea

  • Non-Food Products from the Sea

    • Bioactive Compounds

    • Algin & Agar: products from seaweed

    • Whales: Oil for lubrication, in cosmetics, bones for fertilizer

    • Seals and sea lions: furs

  • Food from the Sea

  • Seaweeds

  • Invertebrates (e.g., oysters, clams, crabs, lobster, squid, etc.)

  • Fish (herring, mackerel, haddock, cod, tuna, mahi-mahi, etc.)

  • Whales

Fisheries management

  • Fisheries management seeks to maintain a long-term fishery by:

    • Assessing ecosystem health

    • Determining fish stocks

    • Analyzing fishing practices

    • Enforcing catch limits

  • Fisheries management does not regulate the number of fishing vessels

Fisheries Mismanagement

Fisheries mismanagement

  • Overfishing

  • Commercial extinction

  • Bycatch (27 million metric tons annually)

  • Targeting smaller species on the low end of the food chain

Bycatch by Gear Type for 2002/2003

Euphausia superba

Who eats Krill?

Krill & the Antarctic Food Web

Critical components of Antarctic food webs

  • Krill Fishery

  • Annual consumption by natural predators = 470 million MT

  • 1972: Japan and Russia began harvesting krill

Krill Fishery…

  • Potential harvest = 25-30 million MT/yr

  • Economic cost of fishery high

  • Patchy distribution complicates location

  • Depths may be 150-200m

  • Single net haul may collect 10 MT

  • Ecological consequences of removal poorly understood

Peru Anchovy Fishery

Peru Anchovy Fishery

  • Upwelling zone off Peru

  • Fishery began 1950

  • Greatest fish catches for any single species

  • Fish exported for domestic animal feed

  • Fishery collapsed due to El Niño and overfishing

Peru Anchovy Fishery

= El Niño






Peru Anchovy Fishery

Normal Year

El Niño Year

  • Collapse of New England Fisheries

  • Cod, haddock, ocean perch, herring, mackerel, blue fin tuna

  • George’s Bank- highly productive, nutrient rich environment

  • Prior to 1976, Russia, Japan, Norway, & West Germany fished in Georges Bank

Collapse of New England Fisheries

Magnuson Act passed & prevented foreigners from fishing in U.S. waters

Fishery technology intensified and resulted in overfishing

Harvests were beyond the max. sustainable yield

Georges Bank closes after collapse

Some fish stocks begin to rebound

Fisheries Management Council

The Magnuson Act created 8 regional fisheries management councils for U.S. waters and regions:

New England FMC

(Saugus, MA)

Mid-Atlantic FMC

(Dover, DE)

South Atlantic

(Charleston, SC)

Gulf of Mexico FMC

(Tampa, FL)


(San Juan, PR)

North Pacific FMC

(Anchorage, AK)

Pacific FMC

(Portland, OR)

Western Pacific FMC

(Honolulu, HI)

Fisheries Management Plans

Congress directed the Councils to manage federal fisheries by creating

Fisheries Management Plans or “FMPs” by:

1. Identifying fish species that need management

2. Analyzing the biological, environmental, economic and social factors that affect the fishery

3. Preparing (and modifying, as necessary) an FMP to protect fishery resources while maintaining opportunities for domestic commercial and recreational fishing


  • Anadromous fish that migrate from sw to fw to spawn

  • Spawning grounds affected by dam construction

  • Aquaculture and restocking efforts

Fish Ladders

Alaska Fisheries

  • Halibut and sablefish

  • IFQ

  • Limited entry


Shark Overfishing

  • Slow growth

  • Low reproductive rate

  • Late sexual maturity

Orange Roughy

  • Distribution: world wide, high concentrations in New Zealand

  • Found: 700-1000m depth

  • Life span: slow-growing, long-lived, ~150 years

  • Size: 30-40 cm

  • Diet: prawns, fish, & squid

  • Reproductive age: 25-30 years old

Fishing Techniques

  • Fishing Methods

  • Harpoon - whales, swordfish, bluefin tuna

  • Pole and line - mahi-mahi and used for tuna extensively in the 50‘s

  • Longline - swordfish, tuna (pelagic); cod, halibut (bottom)

  • Trolling - salmon, albacore, mahi-mahi

  • Drift (gill) netting - various pelagic fish

  • Trawl - anchovies (pelagic); cod, halibut (bottom)

  • Purse seine - sardines, herring, mackerel

  • Traps and Pots - Crabs, lobster, rock fish

Drift Net

net size:

20 m x 65 km


Gill net

Bottom-dwelling fish

Purse seine




Before trawl

After trawl

Trawl from space

Gulf of Mexico, near Louisiana coast. Individual vessels can be seen as bright spots at end of sediment trails. Other bright spots are fixed oil and gas production platforms. One sediment trail can be traced for 27 km. Assuming a standard trawling speed of 2.5 knots, sediment from this trawl is visibly persistent for nearly 6 hours. Water depth <20m. Large, indistinct bright blue patches at lower left and upper right are cloud/haze. (Credit: Landsat)

Laws of the Sea Treaty

Allow nations to claim jurisdiction over their territorial seas (contiguous sea beds and their waters that extend off shore by 12 nautical miles)

  • Exclusive Economic Zone (EEZ)

  • 200 nautical miles

  • under direct control of the country that owns the nearest land

  • Regulates continental shelf resources:

  • Fishing

  • Mineral exploration

  • Scientific research

Exclusive Economic Zone of the United States

Fisheries Problems

& Solutions

  • Fisheries Problems & Solutions

  • Maximum sustainable yield: maximum amount of fish that can be harvested without depleting future stocks

  • World‘s maximum sustainable yield estimated at 100 to 135 million metric tons

  • Present harvests are at about 100 million metric tons

  • For fisheries where numbers available, estimated that 45% are currently over-fished

  • A number of fisheries have already collapsed (Anchovy fishery off Peru, Cod fishery in the N. Atlantic)

Fisheries Problems & Solutions

F. Bycatch (or bykill): animals unintentionally killed during harvest of the target species

Trawling: Bycatch in shrimp trawling is very high (125 to 830% of the catch is discarded as bycatch), turtles often caught in trawls.

SOLUTION: trawls with trap doors to let turtles escape

Purse seine: Tuna known to hang out under pods of dolphins, nets set around pods of dolphins would result in many drowning.

SOLUTIONS: Nets not set around dolphin pods and/or employ — “backing down”, a technique that lowers upper edge of net letting dolphins escape

Dolphins caught in tuna net

Fisheries Problems & Solutions

Driftnets: indiscriminate entangling of many sorts of marine animals

SOLUTION: banned in oceanic fisheries (but some countries still using them)

  • Fisheries Problems & Solutions

  • Long lining: Many albatross drown trying to snatch bait from long lines being deployed. snagged on hooks and pulled under.

  • SOLUTION: deploy in the dark or with special rig to let line out under water.

Global swordfish catch

Ave. wt. in lbs



Mariculture or Aquaculture

(marine agriculture)- farming finfish, shellfish and algae under favorable conditions

Big Island, Kona, Tilapia

One of every four fish eaten today was raised in either a fw or sw fish farm.

84% ofthe 6 million to 7 million tons of seafood consumed each year in the U.S. is imported . About ½ comes from aquaculture.

H. Jones, Time, 2011.

  • Aquaculture also produces:

    • Bait fish

    • Ornamental or aquarium fish

    • Aquatic animals used to augment natural populations

    • Algae for chemical extraction

    • Pearl oysters

  • 2000 years ago in Egypt, Rome, China

  • <2000 years in Hawaii

  • 600 years ago France developed mussel aquaculture

  • 500 years ago Europe developed the idea of using pond fertilizer to promote plankton growth

  • 400 years ago China discovered that oysters would grow on bamboo stakes

  • 1960’s- Europe and U.S. catfish and salmon


Hawaiian Fish Ponds


  • Molokai: South Coast

  • The pond’s walls were made from lava boulders and coral.

  • Walls keep the fish inside while allowing the sea water to ebb in and out.

  • Types of fish raised in ponds:

    • ulua (papio)

    • owama (goatfish)

    • kahala (amberjack)

    • manini (convict tang)

    • palani (surgeon)

    • oio (bonefish)

    • uhu (parrotfish)

  • These fish were kept in a separate pond to breed and raised so they could easily be harvested by hand.

Criteria for selecting species for farming:

-inexpensive to grow

- grows quickly

-high sales price

-resistant to disease and parasites




  • Problems associated with Mariculture:

  • Won’t make a dent in the shortfall in food supply

  • Fish food- fish meal

  • Pollution

  • Escapees

  • Loss of natural habitat

  • Loss of genetic diversity

  • High stress overcrowding pens

  • High concentration of pathogens/parasites

Overcrowded Pens

Parasites & Disease

Salmon with lice

Pollution Under a salmon farm cage

Fish Vaccination

Integrated Aquaculture


Hawaii open ocean aquaculture

Mio, big eye tuna, yellow tail

$34.7 million in 2008

Artificial Reefs

  • Improve the local marine bio-density

    • attract schools of fish

    • providing habitats for the colonization of commercially valuable species

    • improve the local inshore marine harvest

May wash up

on beaches

construction rubble


ship wrecks





Papahānaumokuākea Marine National Monument


Seafood Guide



Seafood Guide


Catfish (farmed imported)

Crab, Kona

Groupers (NWHI)

Lobster (American/Maine)

Octopus (Hawaii)


Trevally/Jack (Hawaii)

Tuna, canned

Tuna, Skipjack (Hawaii longline)

Chilean Seabass

Cod, Atlantic

Mahi mahi (imported longline)

Salmon (farmed)


Shrimp (imported)

Swordfish (imported)

Orange roughy

Tuna, Albacore (worldwide except Hawaii)

Tuna Bige Eye (longline)

Tuna bluefin

Barramundi (U.S. farmed)

Clams (farmed)

Crab, dungeness

Halibut (Pacific)


Swordfish (Hawaii)

Tilapia (farmed)

Skip-jack tuna (troll/poll, handline)


  • What problems are associated with aquaculture?

  • What does fisheries sustainability mean?

  • What occurred shortly after the Magnuson Act was passed?

  • Define the EEZ.

  • What contributed to the demise of the Peru anchovy fishery?

  • Discuss technology changes in the fishing industry in the last 100 years.

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