Overfishing 101: How Science Helps Managers End Overfishing and Rebuild Depleted Fish Populations


NOTE: This is a guest post from Lee Crockett, Director of Federal Fisheries Policy at the Pew Environment Group

This post is the seventh in a series, “Overfishing 101.” The entire series can be viewed here.

I touched on fisheries science in my last post, but here I would like to take a more detailed look at the use of research in setting policy and managing our marine resources.

Industry representatives frequently charge that federal fisheries managers use bad science to make decisions. Nothing could be farther from the truth.

Claim — The federal government sets annual catch limits on many species by guesswork because it doesn’t have accurate population assessments or reliable information on overfishing for the majority of species it manages.

Limited data for popular species of reef fish in the Gulf of Mexico, for example, has been a known problem for decades. But deadlines in the Magnuson-Stevens Fishery Conservation and Management Act (MSA) to establish annual catch limits to end overfishing and rebuild depleted species finally focused attention on this issue. Now, progress is being made to gather more and better data.

However, some short-sighted interest groups are calling on Congress to weaken the law to exempt certain fish species from catch limits because of a lack of “full scientific information.” Ironically, if Congress removes the requirement to set catch limits for these so called “data poor species,” managers would likely shift their limited monitoring and research budgets away from these fish to other species where the legal requirement for catch limits still exists, further exacerbating data problems.

Claims that catch limits cannot be set for “data poor species” are simply false. Currently available information on basic biology, life history characteristics and catch numbers can be used to set quotas for every federally-managed fish, even those without complete assessments. For these populations, managers can base quotas on current catch levels until more complete scientific evidence indicates that the population can support additional fishing pressure. For example, in June of this year, science advisors in the South Atlantic recommended a quota for cobia, a popular sport fish that has not yet been fully assessed, at levels about 25 percent above median landings for the past 10 years. This sensible approach to setting catch limits is based on the stability of the stock, life history characteristics and other data; and gives anglers ample opportunity to target this fish without risking overfishing.

While fishery managers collect more information on individual species, they also could take advantage of a short-term solution by managing several data poor populations as a “complex” (grouping) with similar biological characteristics and vulnerabilities. Then managers can use one or more of the species in the complex that has been assessed as an “indicator species” for the entire group. That information could be combined with other science and catch reports to set annual catch limits for all the species in the affected complex. Fisheries managers then could use those various sources of biology and data to monitor and set annual catch limits for the whole group of species.

The claim that existing science is inadequate wrongly leads some to conclude that managers should allow unchecked fishing unless or until scientific information can show that limits are necessary. That approach has created disastrous consequences in many parts of the country. For example, managers unwittingly allowed overfishing of South Atlantic red snapper for 50 years, reducing the breeding population to 11-14 percent of what scientists consider a healthy level. Allowing fishing without any limits because of doubts about the data is like embarking on a shopping spree without knowing what is in your checking account.

The failure to conserve the fish populations that sustain the fishing economy is a losing long-term proposition. But implementing firm catch limits, based on science, that prevent overfishing will benefit anglers and conservationists alike for generations.

The bottom line: we have the legal and scientific tools in place to restore our ocean fish to healthy levels. We are seeing progress around the country. We now need to finish the job of ending overfishing and rebuilding our nation’s valuable fish populations.

Next time I’ll explore some success stories and policies that will move our fisheries forward in ways that are good for the environment and for communities.

Previous Overfishing 101 posts:

A Beginner’s Guide to Understanding U.S. Fishery Management

How Ocean Fish Populations are Managed in the U.S.

How Ocean Fish Populations are Managed in the U.S. (Part 2)

The Importance of Rebuilding Our Fish Populations Without Delay

Why Ending Overfishing Pays Off in the Long Run

Why Ending Overfishing is Good for Both Fish and Fishermen Alike

Photo: NOAA


Louise F.
Louise Frontiero6 years ago

I see Mr Crockett talks about scientific data in the Gulf of Meico - maybe that is incomplete and there is a concern . But I also noted he does't talk about the Atlantic Northeast .As far as "short-sighted interest groups are calling on Congress to weaken the law " -- he knows there is a lot more to it .....

Janine Hofmann
Janine H6 years ago

Only when the last tree has been cut down; Only when the last river has been poisoned; Only when the last fish has been caught; Only then will you find that money cannot be eaten.
(Native American proverb)

Danny Wilson
Danny Wilson6 years ago

I've never understood why those people have to wipe something out of existence. What are you supposed to eat then? And they want to do this with everything. They just don't get it. I think it's a genetic mutation.

David L.
David L.6 years ago

I don't want to burst anybodies bubble but fishing will never end. But there is space for massive improvement as to how global fishing practices take place. At the moment there are trawlers travelling the globe with massive nets scooping in millions of different fish species and huge amounts dumped as undesirable for human consumption left to perish. At the same time there are ecosystems been totally wiped out due to nets literally scouring the ocean floor destroying everything in its path. Do scientists take that into account? The fishing practice needs a serious review, depleteing fish stocks is one problem and destroying entire ecosystems...its just criminal and does need to stop!!

Carol Joan P.

Regulations based on sound science are necessary. I have read about an idea held by some companies of maximizing short-term profit by taking as much fish as possible, then when populations of that species crash, moving on to a new species. Though under the guise of economics, this is is organized rapacity.

Myron Scott
Myron Scott6 years ago

Congratulations and blessings for your prudence, Grace. As a species we seem inclined to act with reckless disregard for even the reasonably foreseeable potentially negative consequences of our actions. At law, such conduct is a mere half step below deliberate intent: in this case, the reckless murder of our planetary ecosystem.

Steven B.
Steven Bryant6 years ago

Just take a look at the tons of fish rotting around the world.

Amanda D.
Amanda Richards6 years ago

Transferable Quota Systems seem to be the only things that work. Even traditional management systems by indigenous cultures have broken down because of societal changes.

Julianna D.
Juliana D6 years ago


clara H.
Clara Hamill6 years ago

I think that they should study the fish more and try to get better numbers before fishing but people are not going to stop fishing or eat fish we need to make it manageable.