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Making Even Better Decisions About Sea Scallop Harvests

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How do you like to make big, complicated decisions? I like to write lists of pros and cons associated with the choice I’m leaning towards. That’s served me well for changing jobs, selling houses and more.

But for complex systems, like fisheries, simply comparing pros and cons of one choice isn’t enough. There are many moving parts in a fishery, and they are interconnected. For example, when fishermen harvest sea scallops, they reduce the overall number of scallops in an area, and change the age and size distribution of individual scallops. At the same time, factors like rising water temperature, availability of food, or quality of habitat can also affect scallop populations, and external factors like the price of scallops or gasoline can influence the intensity of fishing effort. So, changes in a fishery often lead to outcomes that don’t necessarily generate neat bullets you can compare on a balance sheet.

It’s especially challenging to plan for both short and long term changes in a fishery. Most fisheries are managed to accommodate short-term changes that last a few years, like natural fluctuations in population size. But fisheries management today generally doesn’t also consider long-term changes spanning many decades, like warming and ocean acidification, even though we know those changes are gradually tilting the playing field for many marine species.

My colleagues at Woods Hole Oceanographic Institution and National Oceanic and Atmospheric Administration’s (NOAA’s) National Marine Fisheries Service and I hope to make short- and long-term fisheries planning a bit easier to combine. We’ve just published a computer model that lets us explore the effects of different environmental and economic futures, and compare the results, side by side, for a single fishery. It details alternate universes for the fishery similar to the way that George Bailey saw different futures for his town in “It’s a Wonderful Life.”

We focused on the U.S. sea scallop fishery, which is one of the best managed fisheries in the country. In 2013, it generated $467 million in dockside revenues and has fully rebounded from being overfished in the 1990s. Because there is a trove of stock assessment data about sea scallops and the fishery isn’t in crisis, it’s a good time to look ahead. Our model simulates how environmental conditions influence sea scallop populations, and how harvesting and things like scallop market prices affect the whole system. We can simulate long-term environmental changes including warming and ocean acidification at the same time as we can simulate year-to-year scallop fishery characteristics.

The point of putting this model together is to provide a tool that anyone can use to play out different futures for the sea scallop fishery and that layers short- and long-term changes. Ultimately we’ll build an interactive model website where anyone who’s interested in the scallop fishery can compare the possible effects of different choices and changes on the sea scallop fishery. We hope that this will further inform discussions among harvesters, fishery managers and scientists about how best to manage the fishery in a way that will ensure harvests now and later. We also hope that this type of model can be used for other fisheries in the future, too.  Decision making is never easy, but this model will help us lay out our options a bit more clearly.

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