Size-Selectivity Of The Northwest Atlantic Sea Scallop (Placopecten Magellanicus) Dredge

A size-selectivity curve was constructed to characterize the performance of the New Bedford style Atlantic sea scallop (Placopecten magellanicus, Gmelin 1791) dredge when it is configured to meet the requirements of Amendment #10 to the Sea Scallop Fishery Management Plan. The curve was generated using the SELECT model on catch-at-length data, obtained by simultaneously towing a New Bedford style dredge and a nonselective National Marine Fisheries Service sea scallop survey dredge from commercial scallop vessels. Data were collected during three cruises in the Northwest Atlantic between 2005 and 2006. The resultant selectivity curve yielded a 50% retention length of 100.1 mm, a selection range of 23.6 mm, and a value of 0.77 for the efficiency of the commercial dredge relative to the survey dredge. A length of 100.1 mm corresponds to a meat weight of 17.2 g in Georges Bank and 16.8 g in the mid-Atlantic. These results can assist fisheries managers with stock assessments, fishing mortality estimates, and the interpretation of catch data from resource surveys. Additionally, the curve can be used as a baseline to evaluate the effect of future changes to sea scallop dredge configuration

An Evaluation of Size Selectivity and Relative Efficiency of Black Sea Bass, Centropristis striata, Habitat Pots Equipped with Large Mesh Panels

The black sea bass, Centropristis striata, fishery is in a state of transition. Regulatory changes found in Amendment #9 to the Summer Flounder, Scup and Black Sea Bass Fishery Management Plan implemented measures intended to both rebuild the stock and to maintain it at sustainable levels into the future. These measures included commercial quotas, commercial gear requirements, minimum size limits, recreational harvest limits, and permit and reporting requirements. One vital component contributing to the efficacy of these regulatory measures and future sustainability of the fishery are regulations that effectively protect sub-legal fish. The protection of sub-legal fish not only increases yield to the fishery, but also allows individuals to contribute to the reproductive output of the stock. While measures under Amendment #9 are in place to reduce the capture of sub-legal fish mortality of discarded sub-legal fish, this issue remains a cause of concern to managers. Information gathered by the proposed project will address that concern by demonstrating a means by which the survival of sub-legal fish can be increased over currently mandated methods

Utilizing Fishermen Knowledge and Expertise: Keys to Success for Collaborative Fisheries Research

Collaborative fisheries research provides a mechanism for integrating the unique knowledge, experience, and skills of fishermen and scientists. It is a joint intellectual endeavor that begins with the inception of a project and continues until its final stages, with each group having mutual investment in-and ownership of-the project. Collaborative fisheries research promotes communication and trust among fishermen, scientists, and managers and can provide much-needed scientifically valid data for fisheries management. It can enhance federal and state management data collection programs, which span broad sections of coastline, by increasing the ability to detect changes in local metapopulations that may be over-fished or underutilized. We describe a methodology for conducting collaborative fisheries surveys and apply it to marine protected areas along the central California coast. During a series of workshops in 2006, attended by members of the fishing, academic, environmental, and management communities, protocols were established for conducting hook-and-line surveys collaboratively with commercial passenger fishing vessel captains and volunteer recreational anglers. The protocols have been implemented annually since 2007. This case study highlights the effectiveness of-and the essential steps in-developing our collaborative fisheries research and monitoring projects

The Bioeconomics of Soft Shell Crab: Evaluating the Impacts of Changing Season Length in Oregon's Dungeness Crab Fishery

The Dungeness crab (Cancer magister) fishery is one of the most valuable single species fishery in Oregon, with an average annual ex-vessel value of $45 million from 2004-2014. The fishery is managed using a "3-S" (minimum retention size, male retention only, season length) management paradigm. In addition, fleet capacity has been restricted since 1996, and a system of three tiers of pot limits was implemented in 2006. While a significant literature exists on the biology of the Dungeness crab, and despite the fishery's economic importance to the West coast of the U.S., relatively little is known about either the population dynamics of this stock, the economic behavior of the crab fleet, impacts of crab discards on future catch and biomass, and the economic performance of the fishery relative to its potential. To help us better understand the interaction of the biological stock and industry behavior we develop a bioeconomic model of the Oregon Dungeness crab fishery. The model combines an empirically estimated duration model of intra-season vessel exit behavior with a cohort-based biological representation of the crab stock into a bioeconomic simulation model. Using a Monte Carlo framework, we then examine the potential economic impacts of adjusting: 1) effort levels throughout the season, and 2) season length and timing. The economic performance of the fishery under its current management structure is then compared to the potential performance of the fishery under alternate management options.Proceedings of the Eighteenth Biennial Conference of the International Institute of Fisheries Economics and Trade, held July 11-15, 2016 at Aberdeen Exhibition and Conference Center (AECC), Aberdeen, Scotland, UK

Size-Selectivity of the Commercial Sea Scallop (Placopecten magellanicus) Dredge: Evaluating the Performance of the New Bedford Style Dredge Configured with 4-inch Rings and a 10-inch Twine Top Using the SELECT Model

The print version is considered the official and archival copy of this dissertation or thesis. Researchers are encouraged to consult the archival copy of this dissertation or thesis when citing this work

Data from: Variation in responses of fishes across multiple reserves within a network of marine protected areas in temperate waters

Meta-analyses of field studies have shown that biomass, density, species richness, and size of organisms protected by no-take marine reserves generally increase over time. The magnitude and timing of changes in these response variables, however, vary greatly and depend upon the taxonomic groups protected, size and type of reserve, oceanographic regime, and time since the reserve was implemented. We conducted collaborative, fishery-independent surveys of fishes for seven years in and near newly created marine protected areas (MPAs) in central California, USA. Results showed that initially most MPAs contained more and larger fishes than associated reference sites, likely due to differences in habitat quality. The differences between MPAs and reference sites did not greatly change over the seven years of our study, indicating that reserve benefits will be slow to accumulate in California’s temperate eastern boundary current. Fishes in an older reserve that has been closed to fishing since 1973, however, were significantly more abundant and larger than those in associated reference sites. This indicates that reserve benefits are likely to accrue in the California Current ecosystem, but that 20 years or more may be needed to detect significant changes in response variables that are due to MPA implementation. Because of the high spatial and temporal variability of fish recruitment patterns, long-term monitoring is needed to identify positive responses of fishes to protection in the diverse set of habitats in a dynamic eastern boundary current. Qualitative estimates of response variables, such as would be obtained from an expert opinion process, are unlikely to provide an accurate description of MPA performance. Similarly, using one species or one MPA as an indicator is unlikely to provide sufficient resolution to accurately describe the performance of multiple MPAs

CPUE data and complete model results

This Excel document contains 4 tabs: 1) "Models-7 year analyses" - mixed-model repeated measures analysis of BPUE and mean length estimates for each MPA. 2) "Models-Network analyses" - mixed-model repeated measures analysis of BPUE and mean length estimates across all MPAs. 3) "CCFRP_CPUE_by_gridcell_07-13" - raw data of CPUE for each grid cell each year. 4) "Species codes" - A key for 3 letter codes used for fishes in CPUE table