Despite an eye-watering price tag of approximately $200 billion, the benefits of a concerted effort to restore global fisheries outweigh the costs, according to a new report published in PLoS ONE. The authors claim that such a scheme would pay for itself in 12 years, and see a net gain (if you'll pardon the expression) of up to $1400 billion after 50 years, boosting fishing from a loss-making (when subsidies are considered) to a profit-making industry.

Overfishing can lead to dramatic collapses in fisheries that can have severe knock-on effects for the human communities which have grown dependent upon them. The collapse of the Newfoundland Atlantic cod (Gadus morhua) fisheries in the early 1990s forced the Canadian government to place a moratorium on cod fishing which left thousands unemployed. Acute as the Newfoundland case is, it's by no means isolated.

In 2006, a report in the journal Science co-authored by Dalhousie University's Boris Worm, asserted that one-third of the global fisheries had collapsed (defined, somewhat controversially, by fish catches falling to 10 percent of historic levels), and predicted that most fish stocks would collapse by 2048 if the practices of the time were to continue. A 2009 report saw Ray Hilborn (a critic of Worm's 2006 study) join Worm and others in a less damning assessment, which nevertheless concluded that 63 percent of fisheries were in need of rebuilding.

In their new report, Benefits of Rebuilding Global Marine Fisheries Outweigh Costs, an international team of economists and ecologists reiterate a very simple solution: to fish less. But that's neither as cheap nor as simple as it may sound. If, as the report suggests, current global fishing capacity is 2.5 times higher than that required for sustainable levels, 2.6 million (60 percent) of the world's fishing boats will require decommissioning, and between 15 and 22 million (43–63 percent) of the world's fishers will require compensation or retraining. The authors argue that though this may not be a popular choice in all quarters, a managed transition is preferable to having mass unemployment thrust upon the industry. The researchers have calculated the cost of downsizing to be between $130 billion and $292 billion, with a mean of $203 billion. The report additionally calls for an end to $19 billion per year in "harmful and ambiguous subsidies."

To compare the productivity of fisheries before and after rebuilding, the authors compare "resource rent," which is the net profit from fishing after costs and subsidies have been deducted. The proposed measures would transform a negative annual resource rent (i.e. a loss) of $13 billion into a $54 billion profit, resulting in total gains of between $600 billion and $1400 billion over 50 years (between 3 and 7 times the cost).

Though mean annual catch would eventually increase to a mean of 88.7 million tons per year from 80.2 million tons per year today, most of the gains come as a result of the reduced costs of a downsized fishing industry, which would run on only $37 billion in the rebuilt scenario compared to $73 billion today. Overfishing can increase costs because as stocks are depleted, more boats need to be deployed to maintain catch levels. Sustainably fished resources, by contrast, can be harvested more efficiently.

To arrive at these figures, the researchers examined collected data from a variety of economic, scientific, governmental, and non-governmental bodies to build databases of ex-vessel fish prices (which vary according to species, fishing equipment, and location), fishing costs and subsidies. The data was individually compiled into landed values, costs of fishing, labor costs, fishing company earnings, and fisheries subsidies for 144 maritime countries, from which both current and maximum resource rent, wages, and earnings were calculated.

The following maps, taken from the report, suggest a staggering reversal of fortune for some national fishing industries.

Countries that move out of the red and into the gray would see their fisheries become profit-making, according to the report. Less clear from the maps (but obvious from the data on which they are based) are the massive gains that some already profitable countries, such as USA and China, stand to make:

Inevitably, though, there are gaps in the raw data available. "Global studies such as the current one are only estimates because the datasets are never complete and therefore we develop statistical approaches to fill the gaps," the report's co-author Dr. Rashid Sumalia, director of the Fisheries Economics Research Unit at the University of British Columbia, told Ars. "We have made an effort to include the ranges of parameter values reported in the literature as much as possible. This is why we estimate ranges for our numbers."

The report also assumes that all fisheries will recover to a rebuilt state over time, with an assumed universal rebuild time of 10 years (based on Magnuson-Stevens Fishery Conservation and Management Act). However, Sumalia told Ars that the ranges of possible economic gains account for a range of recovery times, which vary according to species. "Costello et al., cited in our paper, demonstrate that recovery rates for the different taxa they analyzed ranges from 4 to 26 years depending on taxa, for an average of 11 years for the group of taxa they studied," Sumalia told Ars. "We therefore are confident that the combined use of averages and ranges provide strong robustness to our estimates."

The study cited defines a rebuilt fishery as one in which fish stocks achieve equilibrium following an optimized economic fish policy (which doesn't necessarily repopulate fish stocks as fast as possible). Their study is based on 18 hypothetical fisheries, each with a different fish species.

These latest findings would seem to be backed up by analysis of actual fish stocks that have become subject to management with a view to recovery. Even those hardest hit, such as Newfoundland and Nova Scotia, are showing signs of recovery some twenty years on. In 2010 the Northwest Atlantic Fisheries Organization stated that the Grand Banks cod stocks southeast of Newfoundland had grown by 69 percent between 2007 and 2010 (although the 2010 stocks were still only at 10 percent of the levels of the 1960s).

The rebuilding of fisheries is not without its challenges. But far from being a bitter pill that the industry will eventually have to swallow for its long-term survival, this latest research would seem to suggest the process is an economic no-brainer.

PLoS ONE, 2012. DOI: 10.1371/journal.pone.0040542 (About DOIs)