The text on this site is presented as an archival version of the script of "Ocean Planet," a 1995 Smithsonian Institution traveling exhibition. The content reflects the state of knowledge at the time of the exhibition, and has not been updated.

What happens when people catch too many fish?

Fishermen lose their livelihood; other animals may starve. Entire marine ecosystems react to the strain of heavy fishing pressure.

Where have all the codfish gone?

In 1992, the Canadian government closed fishing for Atlantic cod off of Newfoundland, and more than 50,000 people lost jobs §. Several problems contributed to the decline in Atlantic cod: heavy fishing pressure, changes in water temperature, and decline in the cod's prey, a fish called capelin.


Load of cod, near Fogo Island, Newfoundland, before the cod fishery was closed, July 1990
photo © Gordon Peterson


Cod coffin
Fisherman Dan Murphy made this symbol of the closing of the Newfoundland cod fishery in 1992.

Short seasons make fishermen play beat the clock

One way to try to control fishing pressure is to limit the time during which fish can be caught. By 1992, the entire U.S. commercial fishing season for Pacific halibut off Alaska had been pared to two 24-hour openings per year. For two days, fishermen worked round the clock, often in bad weather, risking life and limb to catch as many halibut as humanly possible. §


Regardless of weather and exhaustion, fishermen race against time and each other in the dangerous halibut "derby," Alaska, 1993 Most halibut hooked weigh between 20 and 100 pounds (9.1-45.4 kg), but when a 300-pounder is on the line, the whole crew must help land it §. In 1992, fishermen landed about 60 million pounds (27.2 million kg) during the 48-hour halibut season §
photo © Bob Sacha

Catch quotas may be better for fish, fishermen, and fish consumers

Under the new individual quota system, a certain number of halibut fishermen are given rights to a limited catch. This system could eliminate the "races" in open-season fishing, give more time to handle non-target catch safely, make working conditions safer, let fishermen decide when to fish, bring fishermen higher prices, and bring consumers better, fresher fish. § § ª

With fewer fish to eat, sea lions suffer

Like some birds and other fish-eating mammals in the Bering Sea and northern Gulf of Alaska, Steller sea lions are declining in number. Biologists think that food shortages due to pollock fishing may be one of the major causes of the sea lions' population decreases §.


16,000 pounds of pollock in one haul More pounds of Alaskan pollock were caught in 1993 than any other fish in the U.S. § Steller sea lions also prefer pollock.
photo © NOAA


Steller sea lions fishing for pollock, Alaska Low birth weights and less healthy adults indicate that food shortages may be limiting Steller sea lion and harbor seal populations in some areas of the North Pacific §.
photo © Kennan Ward/Natural Selection

Skates and sharks take over after overfishing

Even the richest fishing grounds can run out of fish. Cod, haddock, and yellowtail flounder were once common catches in the waters above Georges Bank, a vast plateau off New England and Nova Scotia. Now, after three decades of heavy fishing, ineffective management, and environmental changes, nets are full of less valuable skates and spiny dogfish, a small bottom- dwelling shark §.


A haul mostly of skates instead of cod, Georges Bank
photo © Richard Howard

More Information:

A landmark agreement controls fishing to conserve an ecosystem

Fishing, whaling, and seal hunting in past years depleted many species in the Southern Ocean around Antarctica. When interest grew in harvesting the krill that many antarctic birds, mammals, and fish eat, it prompted world leaders to negotiate a new approach to fisheries management. CCAMLR (the Convention for the Conservation of Antarctic Marine Living Resources), a treaty enacted in 1980, requires that regulations managing all Southern Ocean fisheries consider potential effects on the entire antarctic ecosystem §.


Emperor penguin, one of many antarctic species that could suffer from overfishing of krill
photo © Ben Osborne/Oxford Scientific Films


Krill, a vital link in the antarctic food web In 1991 a limit was set on krill catch after CCAMLR evaluated the impact of the krill harvest not only on the krill population but also on other species that depend on these tiny shrimp-like animals for food § §.
photo © Flip Nicklin/Minden Pictures

Other Resources:

Ocean Planet Exhibition Floorplan

gene carl feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)