Study finds encouraging signs for ocean recovery

Some good news about the ocean...
In what sometimes seems like a never-ending wave of bad news for the health of the planet, it's refreshing to come across signs that some things may be getting better:

The Spanish tuna purse seiner, Albatun Dos, While some fisheries are recovering, others like the bluefin tuna are overexploited.A team of researchers has found that fishing pressure on some ocean ecosystems is decreasing . According to a study published in the journal science, fishing rates have dropped in five of the ten large ocean ecosystems that the researchers examined. The team of 19 co-authors arrived at their results by using the ecosystem models Atlantis and Ecosim to analyze ecosystem recovery in 31 fisheries worldwide, 10 in detail. According to the modelling, in seven of the ecosystems, the exploitation rates are low enough to maintain a sustained yield from the system - though this threshold still includes substantial collapse of many species. Two of the systems - the California Current and New Zealand - are fished at a rate low enough to meet a conservation threshold of less than 10% species collapsed.

Upgrading the condition of the sea from 'doom and gloom' to...
Some news sources are embracing the story as a sign that the doom and gloom scenarios put forth by conservationists about the state of the ocean were exaggerated. The drama of the story has been further built up because of alleged past disagreements between two of the study authors, Boris Worm and Ray Hilborn. Supposdely, Hilborn had been critical of Worm's past work as being excessively negative in its characterization of deteriorating marine ecosystems and catering to conservation extremism. Now the two are working together for a common good.

So amid all the hubbub, what does this research really tell us? The authors examined 173 individual species and found that 63% have been depleted beyond the point of sustainable exploitation and require substantial recovery efforts. Of these, 1/2 have seen decrease in exploitation rates which is a positive sign. 14% of the species examined have experienced population collapse. This means that they've had over 90% population loss and are the point where recovery is extremely difficult. Overall biomass is increasing in some ecosystems, decreasing in some, and remaining constant in others.

One thing that I think people need to take into consideration when reading this study is that we're not talking about one day having healthy ocean ecosystems in which species composition and abundance resemble what they were prior to the rise of industrial fishing. We're talking about how to avoid a complete collapse of fish populations and maintain a high enough yield to feed people. Obviously these are critically important goals, but the reality is we're still staring down "doom and gloom" even if the situation appears to be improving.

Fisheries management to the rescue?
The study also identified management tools that are being used to curb over-fishing including catch quotas coupled with strategically placed fishing closures, ocean zoning, selective fishing gear, community co-management and economic incentives (such as individual transferable quotas). The research suggests that these tools are working to reduce exploitation rates although I didn't see concrete causal evidence. For example, how do we know that decreased exploitation isn't being driven at least in part by the fact that fisheries stocks have fallen so far that it's getting harder to catch certain fish.

So for me the take home message of this important study is that the condition of ocean fisheries is really bad but over-fishing is declining in some ecosystems which may allow for recovery. This may be attributable to improved management tools which is very encouraging for the future of the ocean.

Source:	Science
Title:	Rebuilding global fisheries
Authors:	Boris Worm,1, Ray Hilborn,2, Julia K. Baum,3 Trevor A. Branch,2 Jeremy S. Collie,4 Christopher Costello,5 Michael J. Fogarty,6 Elizabeth A. Fulton,7 Jeffrey A. Hutchings,1 Simon Jennings,8,9 Olaf P. Jensen,2 Heike K. Lotze,1 Pamela M. Mace,10 Tim R. McClanahan,11 Cóilín Minto,1 Stephen R. Palumbi,12 Ana M. Parma,13 Daniel Ricard,1 Andrew A. Rosenberg,14 Reg Watson,15 Dirk Zeller15
	1 Biology Department, Dalhousie University, Halifax 2 School of Aquatic and Fishery Sciences, University of Washington 3 Scripps Institution of Oceanography, University of California-San Diego, 4 Graduate School of Oceanography, University of Rhode Island, 5 School of Environmental Science and Management, University of California, Santa Barbara 6 US National Marine Fisheries Service 7 Commonwealth Scientific and Industrial Research Organisation (CSIRO) Marine and Atmospheric Research, Australia. 8 Centre for Environment, Fisheries and Aquaculture Science, UK. 9 School of Environmental Sciences, University of East Anglia, UK. 10 Ministry of Fisheries, Wellington, New Zealand. 11 Wildlife Conservation Society Marine Programs, Kenya. 12 Hopkins Marine Station, Stanford University 13 Centro Nacional Patagónico, Argentina. 14 Institute for the Study of Earth, Oceans, and Space, University of New Hampshire 15 Fisheries Centre, University of British Columbia