Metabarcoding the Gut Contents of Predatory Fish in Coastal Louisiana
Lead PIs: Justine Whittaker and Chris Bonvillain (NIcholls State University). Industry Liaison: Peter Himchak. Contradictory reports cause confusion about the degree to which predators rely on forage fish, specifically Gulf Menhaden (Brevoortia patronus). Most models quantifying the trophic value of Gulf Menhaden incorporate traditional diet studies, involving visual identification of stomach and gut contents. These methods have the potential for misidentification of partially digested prey, but also as much as 20% of contents may be unidentified. Molecular techniques provide additional insight through barcoding of tissue and digested remains. Sequencing DNA from the tissue of partially digested and the slurry of more digested remains, allows more complete characterization of diet. Further, next generation sequencing provides identification of a variety of taxa simultaneously (i.e. metabarcoding). rates of menhaden natural mortality, and the percentage of the population that is allocated for ecosystem needs.
Atlantic Menhaden Stock Review
The project, by Dr. Steve Cadrin (University of Massachusetts Dartmouth), will provide a technical review of the Atlantic States Marine Fisheries Commission’s stock assessment for Atlantic menhaden, as well as provide a new analysis of estimated rates of menhaden natural mortality, and the percentage of the population that is allocated for ecosystem needs.
Evaluation the impact of plus group definition on the Atlantic and Gulf Menhaden stock assessments
Lead PIs: Geneviève Nesslage (UMCES), Robert Leaf (USM), Amy Schuler (NMFS). Industry liaisons: Peter Himchak and Jeff Kaelin. Atlantic and Gulf menhaden are, by volume, two of the largest fisheries in the U.S. But one major source of uncertainty in its stock assessments are the number of older fish in the population. These fish are inadequately assessed by current surveys. The project, from Drs. Genevieve Nesslage (University of Maryland), Robert Leaf (University of Southern Mississippi), and Amy Schuler (National Marine Fisheries Service), will create a new model to simulate how different levels of these older fish would impact the results and accuracy of the menhaden stock assessments.
A Meta-Analysis of the Impact of Forage Fish Abundance on Predator Productivity
Lead PI: Olaf Jensen (Rutgers). Industry liaison: Eleanor Bochenek. There is increased interest and debate surrounding the management of “forage fish” stocks in the U.S. and abroad. A task force funded by the Lenfest Oceans Program has recommended stricter controls on harvest of forage fish to protect predators. This project will evaluate the empirical link between forage fish abundance and predator productivity using a global database of fish stock assessments, trawl survey indices, and abundance time series for select seabird and marine mammal populations.
Design of a Cooperative Winter Pelagic Survey for Atlantic Menhaden in the Mid-Atlantic
Lead PI: Geneviève Nesslage (UMCES). Industry liaison: Jeff Kaelin. The project goal is to design a cooperative winter pelagic survey for Atlantic menhaden in the Mid-Atlantic region to provide estimates of trends in abundance and structure of the northern portion of the stock inhabiting mid-shelf waters during winter and early spring. The current menhaden stock assessment is only informed by northern bottom trawl and seine surveys conducted in inshore waters. This project will help address data deficiencies and better inform the menhaden assessment by designing a winter pelagic survey of the northern portion of the stock in months and areas currently unsampled by midwater gear.
Reproductive Biology & Fecundity of Atlantic Menhaden
Lead PIs: James Gartland, Robert J. Latour, and Wolfgang K. Vogelbein (VIMS): The objective of this investigation was to generate a contemporary evaluation of female Atlantic menhaden reproductive biology that represented a broad spatio-temporal spawning range, and subsequently yield updated estimates of fecundity using methodology that is consistent with the spawning mode of this species.
Finfish Assessment Team
Lead PI: Steve Cadrin (UMass): SCEMFIS has assembled a team of assessment experts from the academic community to provide expertise to develop a benchmark assessment that will meet the stringent demands of peer review. SCeMFiS academics have participated in benchmark assessments for scup, black sea bass, and Atlantic mackerel. The black sea bass assessment recently peer reviewed as the first successful peer review of this species since 2008, in part due to the efforts of SCEMFIS scientists who participated in model development for this challenging fish. Among the innovations was a model that accounted for the spatial structure of this species. Spawning stock biomass is judged to be well above Bmsy leading to the opportunity for increasing quotas for this fishery.
Contributions to the SAW2 Black Sea Bass Stock Assessment. The stock assessment concluded that the stock is well above the rebuilding target (not overfished), and overfishing is not occurring. The SAW62 assessment is a major scientific advancement for improving black sea bass fishery management.
Understanding impacts of fishing forage fish
Lead PIs: Olaf Jensen (Rutgers Univ.) and Robert Leaf (USM): The Lenfest report, “Little Fish, Big Impact,” has had a big impact on the policy arena for fisheries on forage fish, suggesting that harvest policies be much more restrictive, and in many cases, totally prohibit fishing forage fish. Research shows that many populations exhibit substantial natural fluctuations that could cause them to meet these criteria or to be classified as “overfished” even in the absence of fishing or while fishing at FMSY. In general, natural variability is dominant and alternative models provide better description of population dynamics than standard stock assessment models. The objective of this proposal is to address the limitations of the Lenfest forage fish report in collaboration with an international team of researchers assembled by Dr. Ray Hilborn. The SCEMFIS team will re-analyze the data and models considered by the Lenfest task force while considering natural variation and alternative forage species.
Biostatistical and fishery-dependent sampling of Atlantic chub mackerel, round herring, and Spanish sardine
Lead PI: Robert Leaf (USM): The increased interest in “forage fish” stocks, their role as critical ecological components of Mid-Atlantic ecosystems, and the perception that increasing demand exists for fishmeal, fish oil, and bait has resulted in a proposal by the MAFMC to protect forage fish stocks from directed harvest until “adequate scientific information is available.” Many forage fishes, which include round herring, Atlantic chub mackerel, and Spanish sardine, are the target of fishing pressure but are not currently assessed by NOAA or the ASMFC. SCEMFIS will partner with cooperating harvesters to perform biostatistical sampling to examine the life-history characteristics of round herring, Atlantic chub mackerel, and Spanish sardine. The biostatistical data developed in this project will be incorporated into a suite of data limited stock assessment methods and provide a basis for an initial assessment of the status of the stock.
Sex and length of summer flounder discards in the recreational fishery
Lead PI: Daphne Munroe (Rutgers Univ.): A recent stock assessment review of summer flounder identified the need to account for sex-specific fishing mortality in the assessment model. Sex-specific information for the population is collected annually by the National Marine Fisheries Service’s (NMFS-NEFSC) trawl survey. Sex composition of the catch, however, is limited and no information is available on sex composition of discards from the recreational fishery. The absence of information on the sex composition of recreationally discarded summer flounder remains a key need for development of a sex-specific stock assessment model. SCEMFIS will partner with the Save the Summer Flounder Fishery Fund (SSFFF) to support a field program to collect sex-at-length of recreational fishery discards using cooperating for-hire vessels fishing out of New Jersey, New York, and Rhode Island. Data will be incorporated directly into a the assessment model in development.
Morson, J.,*Munroe, D., Harner, R., Marshall, R. 2017. Evaluating the potential for a sex-balanced harvest approach in the recreational Summer Flounder (Paralichthys dentatus) fishery. North American Journal of Fisheries Management 37(6): 1231 – 1242. https://doi.org/10.1080/02755947.2017.1362490 (Final Report)
Other Flounder Research:
Development of a reference point study team
Lead PI: Eric Powell (USM). Biological reference points are used to develop overfishing limits for federally managed stocks. Obtaining the best reference point for any particular stock remains a challenge for assessment scientists. SCEMFIS will further develop the concept of a reference point study team for evaluation.