Fisheries

• Traditional food production and distribution practices are unable to feed the world’s 7+ 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 (bottom dwellers)• Pelagic fish (free-swimming mid/upper

dwellers)• Crustaceans• Mollusks• Marine mammals

Location of the world’s major commercial fisheries

upwellingcoastal areas

Non-Food Products from the Sea • Bioactive Compounds (drugs and

insecticides)• Algin & Agar: products from seaweed

use for promoting gel formation• 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 – international moratorium imposed in

1987; no commercial whaling permitted since with limited exceptions

Case Study: 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

and has NEVER recovered

= El Niño19571965197219761982-83

Peru Anchovy Fishery

Peru Anchovy Fishery

Peru Anchovy Fishery

Normal Year

El Niño Year

• 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

Case Study: Collapse of New England Fisheries

• Magnuson-Stevens Act of 1976 prevented foreigners from fishing in U.S. waters

• Fishery technology intensified and resulted in overfishing – yields well beyond sustainable levels

• Georges Bank closed indefinitely after collapse in ~1994

• Some fish stocks have begun to rebound

Collapse of New England Fisheries

Fisheries Management CouncilThe revised Magnuson Act in 2007 created 8 regional fisheries management councils.

Overfished stocks as of 2010

Fisheries Management Plans

Congress directed the Councils to create Fisheries Management Plans or “FMPs” for each species

•Primarily concerned with balancing growth of stocks with commercial needs

•Established annual catch limits or acceptable biological catch

•Attempted to end overfishing and help stocks recover

Major critics say that the fisheries are still about to crash and that the Councils are mismanaged and ineffective

•Heavily revised in 2010 to be community-based initiatives and saw increased prices with less but more responsible catches as a result in experimental areas

Fishing Techniques

Fishing Methods • Longline – baited hooks (100’s to many

thousands) along a long line; used for swordfish, tuna (pelagic); cod, halibut (bottom)

• Trolling – many lines with single hooks slowly dragged through the water; use for salmon, albacore,

mahi-mahi

Fishing Methods • Drift (gill) netting – vertical nets hung in the

water to trap passing fish• highly controversial!• banned by UN, US limits length to ~1.7 miles • used to catch various pelagic fish

Drift Net

net size: 20 m x 65 km

Fishing Methods • Trawl – large “pouch” dragged through

water/across bottom; used for anchovies (pelagic); cod,

halibut (bottom) • Purse seine – net is wrapped around a school

of surfacing or near surfacing fish; used for sardines, herring, mackerel, tends to accidentally snare any predators like dolphins

Trawl

midwater

bottom

Before trawl

After trawl

Fishing Methods • Traps and Pots - Crabs, lobster, rock fish

• Main problem with most methods is “bycatch” – nontarget species caught and usually killed

Exclusive Economic Zone (EEZ)1. 200 nautical miles (230 land miles)2. under direct control of the country that owns the

nearest land

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

Regulates continental shelf resources:• Fishing• Mineral exploration• Scientific research

Exclusive Economic Zone of the United States

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

Big Island, Kona, Tilapia

Aquaculture also produces:• Bait fish• Ornamental or aquarium fish• Aquatic animals used to

augment natural populations• Algae for chemical extraction• Pearl oysters

Criteria for selecting species for farming:- inexpensive to grow- grows quickly- high sales price- resistant to disease and parasites

tilapia barramundi catfish

Problems associated with Mariculture:

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

• Fish food- fish meal • Pollution • Escapees• High stress overcrowding pens• High concentration of pathogens/parasites

Overcrowded Pens