Trio of Factors Drive Marine Fisheries Production in Northern Hemisphere Ecosystems

Comparative analyses of 13 ecosystems provides insight, potential management tools

The story below was written by Shelley Dawicki, (Research Communications with the Northeast Fisheries Science Center in Woods Hole, MA).  I was very interested in finding out the actual results of these studies so I contacted Shelley and she was kind enough to send me all 10 papers and recommended that I read one particular paper "What drives marine fisheries production?" Since I had served 9 years on the Gulf of Mexico Fishery Management Council, I was familiar with ecosystem management and the desire to move away from single species and into this more holistic approach. Congress has mentioned it on several occasions and most of the regional councils have discussed and/or started work on ecosystem management. 

The studies encompassed practical examinations of the datasets, production models fitted to the available data at multiple levels from single species to full ecosystems, and mockup  studies examining the impacts of climate effects and alternative management strategies on fisheries-production. The body of work presented demonstrates that using both production-modeling and the comparative approach together makes rapid progress towards ecosystem-based fishery management, whether the aim is a better understanding of the ecosystem or the provision of operational management advice. 

Now for the summary that can affect anglers on our charter boats, the analyses presented (within a 2-yr timeframe) highlight the utility of relatively simple models combined with long-term time series maintained by the participating international institutions. The findings reported that multispecies Maximum Sustainable Yield (MSY) is generally LESS than the sum of single species MSY. They also expect that this approach will be useful in other areas of the world, especially where data may be limiting but EBFM is equally as important.

So under these studies and if/when fishery management councils go to ecosystem management we will be looking at lower numbers of fish that can be harvested under this form of management. 

Shelley Dawicki's Story

Comparisons of marine fisheries in thirteen northern hemisphere ecosystems reveal that a trio of factors - fishing, food web/predator-prey interactions, and environmental conditions - drives marine fisheries production. Better understanding of the relative influence of this triad of drivers on fish populations can make fishery management more effective, as well as improve overall understanding of how fisheries work within an ecosystem.

Ten studies, published online July 12 in Marine Ecology Progress Series, identify trends and common patterns governing fisheries productivity in northern hemisphere temperate marine ecosystems. The papers are available as open access articles.

“Marine fisheries occur within the bigger picture of marine ecosystems, and their sustainability is linked to processes that affect the whole system,” said NOAA Fisheries Service researcher Sarah Gaichas of the Northeast Fisheries Science Center (NEFSC), who contributed to several of the studies. “It was a challenge to come up with a fairly simple way to view the data from individual species to the full system level in order to compare ecosystems in Canada, the US and Northern Europe. We did, through the use of a simple production model, a tool that allowed us to organize data from different systems within a common framework. ”

Production models have long been used in fisheries and ecological sciences, and can provide valuable information on ecosystem-based fisheries management. The models require only basic data on catch and biomass, so they are applicable to both well known and more obscure species caught by fisheries. They can also be applied to multiple levels of organization, from single species to groups of species within ecosystems, and can provide ways to measure and express the condition of a stock, a group of stocks, functional groups and for whole ecosystems.

The studies resulted from two international workshops in 2010 and 2011 in Woods Hole, Mass. organized by Jason Link of NOAA’s Northeast Fisheries Science Center. At these meetings, participants assembled the large data set used in the studies. These data describe fisheries, food webs, biological and physical interactions, and environmental times-series information collected on northern hemisphere marine ecosystems.

Researchers have since used the data to compare 13 marine ecosystems off Canada, the US, and northern Europe, all northern subarctic temperate regions. They include the Bering Sea, Gulf of Alaska and Hecate Strait in the North Pacific, Georges Bank and the Gulf of Maine, the Gulf of St. Lawrence, Labrador and Newfoundland, and the Eastern and Western Scotian Shelves off Canada to the North Sea, Norwegian Sea, Baltic Sea and Barents Sea.

“We stepped back and took a big picture look at these thirteen ecosystems with a substantial amount of data and a simple modeling tool,” said Gaichas. “Different factors or drivers are important in different systems, but some common results were found as well, which suggests that our project has identified some fundamental features of marine ecosystems with important management implications.”

The standardized database built for this project provided the foundation for the comparative analyses presented in the studies. The database is itself a significant contribution to ecosystem-based fisheries management given the amount of information it contains: more than 70,000 records including 466 biological and 162 environmental time series across the 13 ecosystems.

“Using production modeling with the comparative approach makes valuable and rapid progress towards ecosystem-based fisheries management, whether the aim is a better understanding of the ecosystem or providing operational management advice,” Gaichas said. “Relatively simple models combined with long-term time series maintained by the participating international institutions are very useful, and highlight the benefits of collaborative projects.”

NOAA and other government researchers, as well as academic scientists from the US, Canada, and Europe contributed to the effort. NOAA Fisheries Service organized and hosted the 2010 and 2011 workshops. The workshops were jointly funded by the US Comparative Analysis of Marine Ecosystems Organization, the Norwegian Research Council, and Fisheries and the Oceans Canada Ecosystem Research Initiative. The NOAA, Canada’s Department of Fisheries and Oceans, and Norway’s Institute for Marine Research also contributed significant resources to this project.