Research

Matthew Oliver, University of Delaware

GRANT AWARDED: February 2014. Bycatch, the unintentional capture of non-target marine species, creates many ecological and management issues for fisheries. Current methods to address bycatch typically involve gear modifications, restrictions, or fishery closures. Although these approaches decrease the amount of bycatch, to date they have not been successful in eliminating it altogether. However, in the Mid-Atlantic region, information from species-specific tracking systems and environmental databases has created an opportunity to develop a tool that will predict the preferred habitats for species susceptible to bycatch and help fishermen avoid the areas. This project, led by Dr. Matthew Oliver at the University of Delaware and Dr. Dewayne Fox at Delaware State University will link observations of two threatened species that are often taken as bycatch—Atlantic sturgeon and sand tiger sharks—with environmental data, such as water temperature and salinity, in order to predict their movement patterns. The result will be an online tool accessible to fishermen and managers through a website, which would show in real time the location of these species, enabling fishing practices to be adjusted to reduce the chance that they will be incidentally caught. If successful, the project would also serve as a case study for other species and regions for which similar data exist.
See below for past issues of the Lenfest Ocean Program newsletter.

Rosamond Naylor, Stanford University

This project will convene a scientific symposium in May 2014, bringing together Chinese scientists and Western scientists to discuss the issue of food security and marine fisheries. China relies on marine fisheries to feed a growing population. Its vessels fish on the high seas and in the waters of other nations. In addition, it is the world’s largest consumer of fishmeal, which is produced mainly from wild-caught forage fish and used as feed for pigs and farmed fish. These activities affect global trade and the management of many fisheries. This symposium will explore these connections in four sessions: 1) the sustainability of high-seas fisheries, 2) the impacts of long-distance fishing on other nations, 3) the economics of the global marine fish trade, and 4) the importance of sustainable forage fisheries for aquaculture. Each session will be co-led by one Chinese and one Western scientist. Dr. Rosamond Naylor, the Director of Food Security and the Environment and a professor at Stanford University, and Dr. Ling Cao, a post-doctoral fellow, will host the event at the new Stanford University Center at Peking University in Beijing, China.

Kelly Stewart (National Marine Fisheries Service, Southwest Fisheries Science Center and The Ocean Foundation)

GRANT AWARDED: November 2012. The five species of sea turtles in U.S. waters—all of which are threatened or endangered—are made up of genetically distinct subpopulations, defined by the beaches where the females lay their eggs. Scientists believe that different subpopulations may play distinct roles in the health of the overall population. For example, Atlantic loggerhead turtles hatched in North Carolina and Virginia are 70 percent male, whereas those that hatch in Florida are 70 percent female. Fisheries bycatch of sea turtles is extensive and, until now, there has not been enough information to determine if a particular fishery is disproportionately taking turtles from a single subpopulation, a scenario that would pose greater risk to the overall population. This project will analyze thousands of tissue samples from both U.S. and international fisheries in the Atlantic and Pacific Oceans and use genetic fingerprinting to identify the native beach of each turtle taken as bycatch. This information will provide the first opportunity to pinpoint specific fishing gears and specific locations that may be disproportionally affecting endangered populations. Managers will then be able to target fisheries that cause disproportionate harm and release fisheries that are less of a threat.

Adrian Jordaan (University of Massachusetts Amherst)

GRANT AWARDED: October 2012. This project will estimate the historical declines of three forage fish populations in the northwest Atlantic and the resulting impacts on the ecosystem. Populations of large predators, such as tuna and cod, are at historic lows. Overfishing is a primary cause, but the overexploitation of their prey also may have reduced the predators’ ability to rebuild their populations. Estimating the declines in forage species could elucidate the impact of their removal on the ecosystem as a whole. The research team will employ historical records and current fisheries data to estimate population declines and then use scientific models to generate anticipated returns of top predators under different forage fish restoration options. This project will generate information to help contrast different policies for setting forage fish catch limits.

William (Monty) Graham (University of Southern Mississippi)

GRANT AWARDED: November 2012. Jellyfish are major consumers of plankton in some ecosystems and may compete with forage fish for this resource. Jellyfish populations can grow quickly in response to abundant prey, producing jellyfish “blooms.” Scientists are increasingly concerned that overfishing may exacerbate naturally occurring jellyfish blooms by increasing plankton availability. This might tip the balance toward jellyfish dominance, which could have adverse economic and ecological consequences. This project will explore a variety of metrics to represent jellyfish as an ecosystem indicator in five marine ecosystems: the Gulf of Mexico, the Northern California Current, the Bering Sea, the Peruvian Upwelling, and the Sea of Japan. Using existing datasets from these regions, the researchers will model the relationships between jellyfish and forage fish and try to identify tipping points in the ecosystem. They will identify thresholds for when the ecosystem shifts and examine the consequences. Fishery managers may use the resulting metrics (e.g. jellyfish biomass and jellyfish to forage fish ratio) to set fishing levels that consider the effects of jellyfish on forage fish.

Tom Miller (University of Maryland Center for Environmental Science)

GRANT AWARDED: November 2012. Atlantic menhaden is a forage fish that is the target of the largest single-species fishery on the east coast of the United States. Historically, menhaden have been managed using biological reference points that focus only on achieving maximum sustainable yield of menhaden. Current management does not consider their crucial roles as prey for predatory fishes or consumers of plankton. This project will develop precautionary, ecosystem-based reference points for managing the Atlantic menhaden fishery. The researchers will use both empirical data and modeling to provide a more holistic understanding of how menhaden function in the ecosystem and to develop, evaluate, and compare candidate ecosystem-based reference points. This research will provide fishery managers with new tools and recommendations for balancing the tradeoffs of different policies. It may also serve as a model for the development and implementation of ecosystem-based reference points for other species in the current single species management framework.

Patrick Halpin (Duke University)

GRANT AWARDED: May 2012. In 2011, the Convention on Biological Diversity established science-based criteria for designating Ecologically or Biologically Significant Areas (EBSAs) on the high seas and instructed regional fisheries management organizations to identify and protect these areas. This project will conduct a global analysis of oceanographic data to identify potential EBSAs that focus on important pelagic habitats for tunas, sharks, seabirds, and endangered species and link oceanographic features with habitat use by large pelagic predators.

Joe Scutt Phillips (University of Southampton, UK)

GRANT AWARDED: July 2012. Many pelagic fishes, turtles, and other marine species are attracted to floating objects in the open ocean, and fishermen have used artificial fish aggregating devices (FADs) to attract fish. In the past few decades, they have deployed thousands of sophisticated FADs with high tech tracking gear and fish finders to catch tuna and other species. This project will examine the impact of FADs in the western and central Pacific on the movement, distribution, health, diet and reproductive potential of tunas. Based on the findings, the researchers will assess different management scenarios such as restricting FAD deployment and time/area fishing closures. This information will provide managers with relevant, actionable science that is directly informative to current tuna management challenges.

Gareth Lawson (Wood Hole Oceanographic Institute)

GRANT AWARDED: July 2012. Forage fish—small schooling fish that provide food for larger species—play a crucial role in many marine ecosystems. Forage species found in deeper waters (> 600ft) have for the most part escaped attention because they are not currently a target of commercial fisheries. Using fisheries-independent trawl and acoustic surveys, this project will examine the distribution, abundance and prey relationship of deep water krill and forage fish, such as myctophids, found off the U.S. continental shelf in the North Atlantic. It will then use stomach content data from commercially important species such as hake, redfish, and swordfish to evaluate the role these deep forage species play in the diet of predators. The assessment will provide managers with a more complete understanding of the ecosystem role of the deep forage. This is important because commercially important predators may feed on these species and, with growing restrictions on herring and menhaden fisheries in shallow waters, it is possible that their deeper counterparts may become an appealing alternative to fishermen.