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Ocean Fisheries Desperately Need New Management Structures

July 28, 1997
University Of California, Davis
While better scientific analyses may help reduce worldwide overfishing and depletion of many ocean fish species, new management systems must be instituted to shield global marine fisheries from the political pressures to over-fish, according to a team of scientists led by a researcher at the University of California, Davis.

July 24, 1997


While better scientific analyses may help reduce worldwideoverfishing and depletion of many ocean fish species, newmanagement systems must be instituted to shield global marinefisheries from the political pressures to over-fish,according to a team of scientists led by a researcher at theUniversity of California, Davis.

In a paper appearing in the July 25 issue of the journalScience, the researchers suggest that the major cause ofoverfishing is political pressure to protect jobs and sustainshort-term profits by increasing the fish harvests. Theeconomic justification for bigger harvests prevails, in part,because it is inherently difficult to predict future fishpopulations.

"The challenge for the next century lies in crafting newlocal and regional institutions, not just in filling thescientific gaps," said Louis W. Botsford, a wildlife andfisheries biologist at UC Davis. "The best hope for greatersustainability of fisheries is to insulate management frompressures for greater harvest, while attempting to reduceuncertainty through a comprehensive ecosystem view."

Collaborating on the study with Botsford were Juan CarlosCastilla of the Pontificia Universidad Católica de Chile inSantiago, Chile, and Charles H. Peterson of the University ofNorth Carolina at Chapel Hill.

Ocean fish provide an important source of food, accountingfor 19 percent of all animal protein eaten by humans.Furthermore, they are the basis for an industry thatemployees 200 million people worldwide and produces an annualcatch valued at $70 billion.

But fisheries around the world, including many in the UnitedStates, are in trouble, note Botsford and colleagues. Theypoint to a recent report by the United Nations Food andAgriculture Organization indicating that global fisheries inthe 1990s are leveling off at about 100 million tons caughtannually. And nearly half of the individual commercial fishspecies are fully exploited, while another 22 percent areover-exploited. Recent examples of overfishing include thecollapse of the cod and haddock populations off of the EastCoast of the United States and Canada.

Perhaps this sorry state of affairs should come as nosurprise. Marine ecosystems --ranging from coastal to deep-sea communities of fish, mammals, turtles, birds and plantlife -- are complex. They are directly impacted not only byhuman enterprises, such as fishing and pollution-producingactivities, but also by large-scale fluctuations in weatherand climate. Fisheries scientists have long been concernedwith annual changes in weather and physical oceanographicconditions, but in recent years they have come to realizethat periodic long-term changes also have profound influenceseven on fish stocks that are separated by great distances.

One such example is the El Niño-Southern Oscillation, awarming of the waters in the eastern Pacific Ocean thatoccurs every five to 10 years. (Scientists believe we are atthe beginning of another large El Niño.) Another example isthe warming of waters off of Alaska in 1976, believed to havetriggered important biological changes that are still ineffect, including an increase in the Alaskan salmon catch anda drop in salmon catches from California waters.

Clearly, the undersea worlds are a challenge to probe andeven more perplexing to wisely manage. While betterunderstanding of the physical variabilities, such as thelarge-scale weather and climate shifts, will yield sounderinformation on which to base management decisions, thepolitical pressures on fisheries management still must bealleviated, Botsford stressed.

"Most overfishing is due to the 'ratchet-effect,' whichoccurs when -- faced with the inherent uncertainties ofpredicting future fish populations -- fisheries managers bendto socio-political pressure to provide jobs and profits forthe fishing industry, leading to greater harvests of fishthan are prudent," he said.

Structurally, fisheries management might be improved bygiving commercial fishers a greater vested interest in thelong-term health of the fisheries. This could be done byoffering them individual transferable quotas or greaterinvolvement in fisheries management. Botsford and colleaguesacknowledge that this would be more difficult at thecorporate level than in small-scale coastal fishingoperations. It would be particularly difficult ininternational fisheries, where existing institutionalstructures and cultural differences don't encouragecooperation.

The researchers suggest that several changes in the way marinefisheries are managed would improve sustainability, regardlessof improvements in marine science. First, they urge adoptionof the precautionary approach to fisheries management, whichwould translate into lower levels of fish harvests unlessscientific evidence clearly demonstrates that higher catchrates are warranted.

Secondly, Botsford and colleagues suggest establishing marinerefuges that are off-limits to fishing in order to protectportions of exploited fish populations and allow thosepopulations to rebuild themselves.

And finally, they advocate more liberal use of closures andfishing moratoria to protect declining fish populations orstressed ecosystems before, instead of after, a fishpopulation collapses.

The fisheries management study was funded by the PewCharitable Trust, the Center for Marine Conservation, theU.S. Global Ocean Ecosystems program and Sea Grant.

Media contact:-- Louis Botsford, Wildlife, Fish and Conservation Biology, (916) 752-6169-- Patricia Bailey, News Service, (916) 752-9843,

-------------------------------------------------More university news and an experts directory: Davis News Service; Davis, California(916) 752-1930,

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University Of California, Davis. "Ocean Fisheries Desperately Need New Management Structures." ScienceDaily. ScienceDaily, 28 July 1997. <>.
University Of California, Davis. (1997, July 28). Ocean Fisheries Desperately Need New Management Structures. ScienceDaily. Retrieved March 26, 2017 from
University Of California, Davis. "Ocean Fisheries Desperately Need New Management Structures." ScienceDaily. (accessed March 26, 2017).