Incorporating industry based dredge surveys into the assessment of sea scallops, Placopecten magellanicus

Cooperative research utilizing industry vessels represents a viable approach to acquire the data necessary to meet the increasing needs associated with the modern management of marine resources. This dissertation addresses a variety of topics associated with the integration of commercial vessels into the stock assessment of the sea scallop, Placopecten magellanicus. In this study we evaluate the efficacy of utilizing industry vessels with respect to topics that range from rotational closed area survey design, sampling gear evaluation as well as an experiment that broadens the scale of the traditional use of industry vessels in this fishery and provides data to support the use of commercial vessels for surveying sea scallops resource wide. The first paper presents a methodology to evaluate candidate sampling designs for closed area surveys. We simulated scallop populations within a closed area based upon both empirical data and an analysis of the autocorrelation structure of the scallops in that area. From the simulated realizations of the scallop abundance and distribution, three different sampling designs at three levels of sampling were evaluated with respect to bias and accuracy of both mean abundance and variance of the sample mean. The second and third papers take advantage of the ability of commercial vessels to simultaneously tow two dredges. Based on this ability, in the second paper, we estimate the size selectivity of the currently mandated New Bedford Style sea scallop dredge. In addition to estimating the size selective characteristics of this piece of gear, we also estimate the efficiency of the dredge. Both measures are important with respect to correctly estimating the exploitable biomass of sea scallops in rotational sea scallop closed areas. The third paper again used paired data to evaluate the relative changes in the performance of the NMFS sea scallop survey dredge. We utilize a Generalized Linear Mixed Modeling (GLMM) approach to analyzing these data with the goal of characterizing any structural changes in the performance of the dredge that is used to survey both specifically scallop closed areas as well as the entire resource via the annual NMFS time series since the 1970\u27s. The final paper broadens the scale of the utilization of industry vessels and calibrates two of these platforms to the NMFS annual sea scallop survey. We evaluated four separate vessel gear combinations relative to the R/V Albatross IV, throughout the range of the U.S. sea scallop resource and present information to either utilize these vessels to conduct the survey, or at least form a link to a future platform. The results in this dissertation demonstrate that industry vessels represent a feasible option for the collection of sea scallop stock assessment information and present both methods and current information to facilitate their use. These approaches are especially applicable for sea scallops, where the management for this species embraces the spatial characteristics of the underlying population and crafts appropriate management strategies

A Cooperative High Precision Dredge Survey to Assess the mid-Atlantic Sea Scallop Resource : Final Report

For the sea scallop, Placopecten magellanicus, the concepts of space and time have emerged as the basis of an effective management tool. The strategy of closing or limiting activities in certain areas for specific lengths of time has gained support as a method to conserve and enhance the scallop resource. In the last decade, rotational area management has provided a mechanism to protect juvenile scallops from fishing mortality by closing areas based upon scallop abundance and age distribution. Approximately half of the sea scallop industry’s current annual landings come from areas under this rotational harvest strategy. While this represents a management success, it also highlights the extent to which landings are dependent on the success of this strategy. The continued prosperity of scallop spatial management is dependent on both periodic and large incoming year classes, as well as a mechanism to delineate the scale of a recruitment event and subsequently monitor the growth and abundance of these scallops over time. Current and accurate information related to the abundance and distribution of adult and juvenile scallops is essential for managers to respond to changes in resource subunits. Acknowledging the importance of accurate, timely and meaningful information necessary to meet the management challenges presented by this situation, the Virginia Institute of Marine Science (VIMS) conducted a synoptic high resolution (~450 stations) survey of the mid-Atlantic (MAB) scallop resource from the VA/NC border to Block Island, RI encompassing the Delmarva (DMV), Elephant Trunk (ETCA), and Hudson Canyon (HCCA) Access Areas, as well as the open areas of the MA resource area during the spring of 2016 and 2017. The primary objective of these surveys was to assess the abundance and distribution of sea scallops in this area, culminating with spatially explicit annual estimates of total and exploitable biomass. Secondary project objectives for each survey year included: 1. Finfish bycatch species composition and catch rates, 2. Scallop biological sampling (length:weight relationship, disease, product quality parameters and shell samples for ageing) and 3. Selectivity and relative efficiency analysis of the Coonamessett Farm Turtle Deflector Dredge (CFTDD)

A Cooperative High Precision Dredge Survey to Assess the Mid-Atlantic Sea Scallop Resource Area in 2019 and 2020: Final Report

For the sea scallop, Placopecten magellanicus, current and accurate information related to the abundance and distribution of adult and juvenile scallops is essential for effective management of the resource. Scallop management is a combination of input and output controls, with a focus on spatial area management. The continued prosperity of the scallop resource and fishery is dependent on both periodic and large incoming year classes, as well as a mechanism to delineate the scale of a recruitment event and subsequently monitor the growth and abundance of these scallops over time. Acknowledging the importance of accurate, timely, and meaningful information necessary to meet the management objectives and support the fishery, the Virginia Institute of Marine Science (VIMS) conducted a synoptic high resolution stratified random survey of the Mid-Atlantic Bight (MAB) scallop resource from the VA/NC border to Block Island, RI encompassing the Mid-Atlantic Access Area (MAAA), as well as the open areas of the MAB resource area during the spring/summer of 2019 and 2020. The primary objective of these surveys was to assess the abundance and distribution of sea scallops in this area, culminating with spatially explicit annual estimates of total and exploitable biomass by Scallop Area Management Simulator (SAMS) Area. Secondary project objectives for each survey year included: 1. Finfish bycatch species composition and catch rates, 2. Scallop biological sampling (length:weight relationship, disease, product quality parameters, and shell samples for ageing), and 3. Sea scallop dredge performance (commercial and survey dredges)

An Assessment of Sea Scallop Abundance and Distribution in Georges Bank Closed Area II and the Southern Extension Closure: Final Report

For the sea scallop, Placopecten magellanicus, the concepts of space and time have emerged as the basis of an effective management tool. The strategy of closing or limiting activities in certain areas for specific lengths of time has gained support as a method to conserve and enhance the scallop resource. In the last decade, rotational area management has provided a mechanism to protect juvenile scallops from fishing mortality by closing areas based upon scallop abundance and age distribution. Approximately half of the sea scallop industry’s current annual landings come from areas under this rotational harvest strategy. While this represents a management success, it also highlights the extent to which landings are dependent on the success of this strategy. The continued prosperity of scallop spatial management is dependent on both periodic and large incoming year classes, as well as a mechanism to delineate the scale of a recruitment event and subsequently monitor the growth and abundance of these scallops over time. Current and accurate information related to the abundance and distribution of adult and juvenile scallops is essential for managers to respond to changes in resource subunits. For the present study, we conducted a stratified random survey of the Georges Bank Closed Area II (GBCA II) scallop access area and the GBCA II Extension closure to the south. The primary objective of this survey was the determination of scallop distribution, abundance and biomass in the area. In addition, we characterized the spatially explicit scallop length weight relationship, identified areas of seed and juvenile scallops, quantified species-specific bycatch, provided additional information regarding the size selectivity and efficiency of the New Bedford style commercial dredge and collected data on scallop biology and market condition. We also conducted a tow duration experiment after the conclusion of the survey to assess the impact of a shorten tow duration on scallop catch

Georges Bank Yellowtail Flounder Estimates from VIMS Industry-Based Scallop Dredge Surveys of Closed Area II and Surrounds

This document is the final report submitted to the New England Fishery Management Council (NEFMC) for the Georges Bank Yellowtail Flounder Estimates from VIMS Industry-Based Scallop Dredge Surveys of Closed Area II and Surrounds project. The NEFMC funded this project in April 2019, with an objective of synthesizing existing VIMS dredge survey data with respect to the Georges Bank stock of yellowtail flounder (Limanda ferruginea). Analysis consisted of an examination of existing catch data from VIMS dredge surveys of Georges Bank Closed Area II and surrounds from 2005 to 2019

An Assessment of Sea Scallop Abundance and Distribution in Georges Bank Closed Area II and Surrounds : Final Report

For the sea scallop, Placopecten magellanicus, the concepts of space and time have emerged as the basis of an effective management tool. The strategy of closing or limiting activities in certain areas for specific lengths of time has gained support as a method to conserve and enhance the scallop resource. In the last decade, rotational area management has provided a mechanism to protect juvenile scallops from fishing mortality by closing areas based upon scallop abundance and age distribution. Approximately half of the sea scallop industry’s current annual landings come from areas under this rotational harvest strategy. While this represents a management success, it also highlights the extent to which landings are dependent on the success of this strategy. The continued prosperity of scallop spatial management is dependent on both periodic and large incoming year classes, as well as a mechanism to delineate the scale of a recruitment event and subsequently monitor the growth and abundance of these scallops over time. Current and accurate information related to the abundance and distribution of adult and juvenile scallops is essential for managers to respond to changes in resource subunits. For the present study, we conducted a stratified random survey of the Georges Bank Closed Area II (GBCA II) scallop access area and the GBCA II Extension closure to the south. The primary objective of this survey was the determination of scallop distribution, abundance and biomass in the area. In addition, we characterized the spatially explicit scallop length weight relationship, identified areas of seed and juvenile scallops, quantified species-specific bycatch, provided additional information regarding the size selectivity and efficiency of the New Bedford style commercial dredge and collected data on scallop biology and market condition. We also conducted a tow duration experiment after the conclusion of the survey to assess the impact of a shorten tow duration on scallop catch

A Cooperative High Precision Dredge Survey to Assess the mid-Atlantic Sea Scallop Resource in 2018: Final Report

For the sea scallop, Placopecten magellanicus, the concepts of space and time have emerged as the basis of an effective management tool. The strategy of closing or limiting activities in certain areas for specific lengths of time has gained support as a method to conserve and enhance the scallop resource. In the last decade, rotational area management has provided a mechanism to protect juvenile scallops from fishing mortality by closing areas based upon scallop abundance and observed age distribution. Approximately half of the sea scallop industry’s current annual landings are attributed to areas under this rotational harvest strategy. While this represents a management success, it also highlights the extent to which landings are dependent on the effective implementation of this strategy. The continued prosperity of scallop spatial management is dependent on both periodic and large incoming year classes, as well as a mechanism to delineate the scale of a recruitment event and subsequently monitor the growth and abundance of these scallops over time. Current and accurate information related to the abundance and distribution of adult and juvenile scallops is essential for managers to respond to changes in resource subunits