Source Newsroom: Dalhousie University
Newswise — It was like Superman calling out Batman " fisheries scientist Ray Hilborn publicly criticizing the findings published by Dalhousie marine ecologist Boris Worm in 2006 suggesting the world's oceans could run out of fish by 2048 if overfishing was allowed to continue. In questioning Dr. Worm's projections, Dr. Hilborn, of the University of Washington, set off a media and scientific frenzy wondering how two of the most respected experts in their respective fields could be oceans apart in their views.
During such a public debate it would be hard to imagine a quick reconciliation between the two, but when they met during a call-in show on National Public Radio, that's exactly what happened. "Through our discussions we realized we were actually not that far apart," says Dr. Worm. "We became curious to see if we could find more common ground and whether this could bring those two disciplines closer together."
As it turns out, the answer was yes. The two combined efforts and along with a team of 19 co-authors, published "Rebuilding Global Fisheries," which appears in the July 31 issue of Science. One observer termed this new partnership "a success of the scientific method."
While fisheries science and marine ecology are both interested in fish, they differ in method. Fisheries science often sees fish primarily as a resource and try to determine the level at which it can be extracted at a sustainable rate. Marine ecologists see fish as part of an ecosystem and tend to be more conservative in how much can be taken out without harming the ecosystem.
While their methods and interpretations differed, the collaboration unearthed one important discovery " both sides were actually right.
The findings of the paper have given a new hope to scientists that something can be done to stop over-exploitation of fish stocks. Led by Dr. Worm and Dr. Hilborn, the team studied fish abundance and exploitation rates (proportion of fish taken out of the sea) in ten different ecosystems where steps were taken to decrease overfishing. They also studied the tools fisheries managers had applied to make this happen.
"We didn't look only fishery by fishery, we also looked ecosystem by ecosystem," explains Dr. Worm. "One of the novel things we did here was find out whether the pressure we put on ecosystems by fisheries is going up or down and the good news is that the pressure on the ecosystem is decreasing overall in half of the ten systems we have detailed data for."
While it may seem like a glass half-empty or half-full debate, the findings give Dr. Worm a renewed hope that if proper, timely management is applied, fish stocks can be rebuilt.
"I think it gives us hope that something can be done and it's not just an idea as we now have the results to show the world."
Dr. Worm explains that a diversity of solutions is necessary. While it begins with reducing catches, closing certain areas, regulating fishing gear and reducing the capacity of fishing fleets, each area will have to do things specific to that ecosystem.
In places like Eastern Canada, little was done to prevent the collapse of fish stocks like cod. Now, attempts to rebuild are struggling. Meanwhile, in places like Alaska and New Zealand they've had success by not waiting until drastic measures are needed and taking a pre-emptive approach to conserve their fish stocks. As a result of reducing their exploitation rates after a period of overfishing, California, New England and Iceland are now seeing recovery of fish stocks. Even in developing countries like Kenya, over many years of consultation with fishermen they are producing results that are not only good for the ecosystem but also for fishermen.
Dr. Worm is pleased that fisheries and the oceans in general are getting more attention from society and policy makers, but cautions against believing all is well as these positive steps are still few and far between.
"We don't want to spread complacency but I also worry about the people who think it's hopeless " we have to be able to show why it's worth taking action," he says.
"There is more awareness now that the ocean is important for more than just providing food, but a host of other services that are quite frankly crucial to our survival," he explains. "There is a sense that things are going wrong and things like the collapse of the cod fishery have made us realize we need to do something."
The results of the paper also show that overfishing can be discouraged by restructuring incentives. Programs like catch-shares offer fishermen stock in the overall catch, therefore if fisheries are doing well, so will they, but if it collapses they get nothing so it's in their best interest to not only make sure they don't overfish but that others don't as well.
The initial paper offers an overview of the study and more results will follow in the coming months and years casting more light on practical and effective practices for management and to cut exploitation. The project and working with Dr. Hilborn have been great experiences for Dr. Worm.
"I'm very happy we did this, that it's worked out and we got together and hammered out our differences," he explains. "I think it's good for the respective fields because we need to move forward together. After all, there is only one world and we better work on that world together."
As individuals we need to ask ourselves can we make long term sustainability the undercurrent of everything we do? We can contribute to solutions or we can contribute to problems, it's a simple choice."