Alexander, Ricky1, Farrell Davis1, Chris Parkins2, and Ron Smolowitz1. A modified flounder sweep for flatfish bycatch reduction in the LAGC scallop fishery.
1Coonamesset Farm, Falmouth, MA, 2Rhode Island Department of Environmental Management, Jamestown, RI
Limited-Access General Category (LAGC) scallop vessels in Northeast region are generally small (< 60 feet), and therefore more spatially and temporally restricted than the Limited-Access fleet. Due to this limitation, the LAGC fishing season is typically a function of fishing conditions, rather than management restrictions. Further, there may be an increase in bycatch due to temporal and spatial overlap of nearshore fish migrations. Interactions by the LAGC fleet with managed flatfish species could result in the implementation of Accountability Measures (AM), potentially jeopardizing the fleet’s profitability. One approach to avoid exceeding Annual Catch Limits (ACL) and triggering an AM is to develop gear based solutions for mitigating bycatch. To that end, a cookie sweep was attached to the outer bale bars of a scallop dredge forward of the cutting bar to drag the bottom, creating a sand cloud that initiates a herding (escape) response from flatfish, which, in turn, should result in a lower catch rate of flatfish. If effective, the flounder sweep could prevent the need for seasonal closures of nearshore fishing grounds that could have severe impacts for the LAGC fleet. In the fall 2016, testing of the flounder sweep began aboard an active LAGC scallop vessel. Preliminary results are promising with an 11.35% decrease in total bycatch of all finfish species and a 14.66% decrease in flatfish bycatch. These results indicate that the flounder sweep may be effective in reducing finfish bycatch, without impacting gear handling or target species catch, sea scallop (Placopecten magellanicus).
Apell, Bryan1. Field methods for evaluating passage of adult American Shad at the Turners Falls and Northfield Mountain Projects.
The Turners Falls Hydroelectric and Northfield Mountain Pump Storage Projects (NMPS) are currently undergoing relicensing. The projects are on the Connecticut River in Massachusetts and located within the diadromous fish migratory corridor. The American shad is a species of particular interest to resource agencies and stakeholders and represents the largest diadromous migration in the Connecticut River drainage. In 2015, FirstLight conducted a telemetry-based study to investigate the behavior, routes of passage, passage success, survival, and delay of American shad as they encounter the Projects during both upstream and downstream migration. Radio and Passive Integrated Transponder (PIT) telemetry methods were employed to track nearly 800 shad as they migrated through the projects. A total of 29 fixed radio telemetry monitoring stations and 13 PIT monitoring stations were deployed to track the tagged shad migration throughout the 43 river mile study area extending from Holyoke to Northfield, MA. Additional data were collected during 33 mobile surveys. This presentation will concentrate on the technologies and field methods employed. Data analysis methods and results will be presented during a later presentation.
Bell, Richard1, Anthony Wood2, Jonathan Hare2, David Richardson2, John Manderson2, and Timothy Miller2. Rebuilding in the face of climate change.
1The Nature Conservancy, 2Northeast Fisheries Science Center
Rebuilding plans provide a legally binding time-line to reduce overfishing. For many species along the Northeast US Shelf, heavy fishing pressure severely depleted populations and was the major driver controlling stock status. As fishing pressure declined, the potential increased for the physical environment to influence intrinsic rates such as growth, mortality, and fecundity. Decadal-scale climate variability and climate change can cause trends in oceanographic conditions over the course of rebuilding plans, and thus rebuilding projections developed assuming constant intrinsic rates may not be realistic. Winter Flounder is an important commercial and recreational species that has declined in the southern portion of its range despite reduced fishing pressure. Laboratory and mesocosm studies suggest that stock productivity is reduced under warmer conditions and that rebuilding to historical levels may not be possible. Our goal was to examine the rebuilding potential of Winter Flounder in the face of regional warming. We integrated winter temperature into a population model to estimate environmentally driven stock-recruit parameters and then used the parameters to project the stock into the future under different climate and fishing scenarios. The inclusion of winter temperature had very little impact on the estimates of abundance, but provided greater understanding of the drivers of recruitment. Future projections suggest that rebuilding the stock to historical levels is unlikely, but specific biomass projections depend heavily on model assumption. The integration of both fishing and the environment has the potential to provide more realistic expectations of future stock status.
*Calabrese, Nicholas1 and Kevin D.E. Stokesbury1. A video trawl survey for Atlantic Cod (Gadus morhua) in New England.
1Department of Fisheries Oceanography, School for Marine Science and Technology, University of Massachusetts Dartmouth.
Researchers at the School for Marine Science and Technology (SMAST), in collaboration with members of the fishing industry, have developed a survey system that utilizes a live feed video camera mounted in the codend of a demersal trawl. This system can be towed with an open codend allowing fish to be recorded, identified, and quantified as they pass through, or with a closed codend periodically to collect biological information and verify video observations. Seven field trials have been conducted on Georges Bank with the intent of identifying flatfish. In January 2016 a pilot study in the Gulf of Maine applied these same methods to survey Atlantic cod (Gadus morhua). With the 19 hours of video collected we plan to test the following hypotheses: (1) there is no difference between the number of cod counted from the video and in the catch; (2) there is no difference between the number of cod counted by sampling the entire video and subsampling the video; and (3) the distribution of Atlantic cod along the path of each tow is uniform. Preliminary results show no significant difference (P>0.05) between the catch and video counts of cod. This approach could provide a non-invasive method of surveying aggregations of Atlantic cod in the Gulf of Maine and in conjunction with the existing fisheries independent surveys could strengthen the assessment of this stock.
*Davis, Farrell1, Liese Siemman1, David Rudders2, and Ronald Smolowitz1. The impact of increasing the inter-ring spacing on scallop dredge efficiency.
1Coonamessett Farm Foundation, East Falmouth, MA, 2Virginia Institute of Marine Science, Gloucester Point, VA.
Large sea scallop (Placopecten magellanicus) recruitment events in scallop rotational access areas can create a situation where high densities of pre-recruit scallops are found amongst commercially viable densities of harvestable scallops. Under these circumstances there is a real likelihood that recruitment overfishing could occur as a result of high discard mortality associated with thermal shock and desiccation. Modifications to the scallop dredge bag configuration to increase the selectivity could reduce the impact of fishing effort on pre-recruit scallops while allowing for the harvest of commercial sized scallops. By using two links rather than a single link to connect the rings of the apron together, the inter-ring spacing can be increased both vertically and horizontally altering the selective properties of the dredge bag. Preliminary analysis of the data collected during four research trips, one of which utilized a non-selective dredge bag, indicates that this configuration has the potential to reduce the bycatch of pre-recruit scallops as well as elasmobranchs and finfish.
Davis, Justin1 and Eric Schultz2. Simulation models of the predator-prey interaction between Striped Bass and Blueback Herring in the Connecticut River.
1Connecticut Department of Energy and Environmental Protection, Marine Fisheries Division, Old Lyme, CT. 2 University of Connecticut, Storrs, CT.
Case studies of the ramifications of predator management for prey population dynamics can play a valuable role in developing ecosystem fisheries management approaches. Atlantic coastal populations of Striped Bass (Morone saxatilis), a large predatory finfish of significant fisheries value, have been rebuilt to high levels of abundance in recent decades. The spawning run of Blueback Herring (Alosa aestivalis) to the Holyoke Dam on the Connecticut River in southern New England has collapsed coincident with Striped Bass recovery; our previous study of this predator-prey interaction in the Connecticut River suggested that annual Striped Bass in-river consumption of herring was substantial, and that increased in-river Striped Bass harvests might modestly improve herring survival. Here we incorporate our measurements of predation rates into a herring population model to test whether increased Striped Bass predatory demand can account for the collapse of the Holyoke Dam run, and whether alternative management of the in-river recreational Striped Bass fishery can substantially improve prospects for run recovery. Over half of our simulations incorporating estimates of Striped Bass predation during the 1980-2000s predicted the observed collapse of the Holyoke run; further, current rates of Striped Bass predation in the river stretch below Holyoke Dam appear sufficient to prevent run recovery. Implementation of alternative regulations that encourage increased Striped Bass harvests by recreational anglers offer only limited potential to aid herring recovery; the levels of additional harvest required to substantially improve predicted future herring returns are unlikely to be achieved at observed levels of fishing intensity. Our model illustrates potential trade-offs between predator and prey management initiatives, provides estimates of uncertainty associated with those trade-offs, and highlights important areas for further research into this important predator-prey interaction.
*Devine, Matthew T1, Allison H Roy1,2,3, Andrew R Whiteley4, Benjamin I Gahagan5, Michael P Armstrong5, Michael M Bailey6, and Adrian Jordaan1. The lake effect: identifying optimal growth conditions for juvenile anadromous Alewife.
1Department of Environmental Conservation, University of Massachusetts-Amherst, Amherst, MA 01003, 2Massachusetts Cooperative Fish and Wildlife Research Unit, 3U.S. Geological Survey
4Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT 59812, 5Massachusetts Division of Marine Fisheries, Annisquam River Marine Fisheries Station, Gloucester, MA 01930, 6U.S. Fish and Wildlife Service, Central New England Fishery Resources Office, Nashua, NH 03063
Anadromous alewives (Alosa pseudoharengus) have experienced substantial population declines over the past five decades due in part to habitat degradation and overfishing. Current management objectives include restoring alewives to historic spawning habitats, yet favorable conditions are not well described. Without understanding what constitutes ideal conditions, restoration strategies and locations are limited. We used generalized linear mixed models to explain the variation in growth rates in 10 coastal New England lakes (natural n=7; stocked n=3) sampled monthly from June-August of 2015. Juveniles were sampled by purse seine, and preserved in 95% ethanol. Physical (e.g. size, depth, temperature) and chemical (e.g. phosphorous, dissolved organic carbon) lake properties were also measured or collected during fish sampling. In the lab, total fish length was measured and otoliths from 50 fish per month for each lake were extracted, mounted in resin, and double-aged. Length-based growth was calculated for individuals and averaged across lakes and months. Monthly alewife densities were calculated and used in models. Individual growth rates varied wildly (0.53±1.61 mm/d) among lakes, and low density stocked systems exhibited higher growth rates (mean SE = 1.04 ±0.020) than natural systems (0.891 ±0.017), suggesting density dependent growth as a key mechanism. These results are consistent with others, and suggest management based solely on run size may impact juvenile productivity. This and future exploration of size-selective mortality and size at age events (e.g. egress, diet shifts) will eventually aid site selection for restoration projects, such as dam removal and stocking events, and produce effective management strategies.
Dey, William1, Brooks Fost2, and John Young2. Can fish eggs and larvae survive a trip through the cooling system: What have we learned since 1972?
1ASA Analysis & Communication, Washingtonville, NY 2ASA Analysis & Communication, Lemont, PA
316(b) of the CWA Amendments of 1972 initiated a tremendous amount of research on the impacts of fish being trapped on power plant water intake screens (impingement), and passage of fish eggs and larvae through the cooling system (entrainment). At that time, conventional wisdom held that passage through the cooling system was always fatal, a result of the combined effects of physical damage, high temperatures, and biocides. Actual measurement of the probability of surviving entrainment presents unique sampling challenges, and required intensive research, most of it performed at estuarine facilities within the boundaries of the NED, to develop specialized sampling equipment and protocols. By 1980, the reality of entrainment survival was an accepted part of 316(b) knowledge. However, at that point most power plants had obtained permits for their water discharges, and interest in 316(b) research, particularly entrainment survival, waned. When USEPA published its new regulations for 316(b) in 2004, it reverted back to the original premise of 100% mortality. This retrogression was reversed in 2011 when revised regulations allowed for entrainment survival to be demonstrated. This has led to a resurgence of entrainment survival studies at several coastal facilities in NED states. The new studies have concentrated on fish eggs, and have, as before, required further development of techniques and equipment. Also, as before, the studies demonstrated that passage through the cooling system is survivable by a large proportion of the entrained organisms.
*Ellis, Laura1, Walt Golet2,3, and James Suljkowski1. Using skeletal muscle tissue to determine the sex specific ratios of Atlantic Bluefin Tuna (Thunnus thynnus) in the New England Fishery.
1University of New England, 2University of Maine, 3Gulf of Maine Research Institute, Portland, ME
The Atlantic Bluefin Tuna (Thunnus thynnus) is a large, highly migratory and highly prized commercial fish species. Historical overexploitation led to a 20-year rebuilding plan initiated in 1998, and current assessments still lack fundamental biological inputs. Routine biological sampling has been problematic given the nature of the fishery (evisceration at sea). As a result, gross examination of specific tissues (e.g. gonads) to determine reproductive characteristics of the fished population has not been possible. To overcome these challenges, an alternative technique for assessing reproductive biology must be utilized. Previous studies have quantified sex hormones reliably to determine the reproductive characteristics of various fish species. Building off this premise, radioimmunoassay was used to quantify estradiol (E2) and testosterone (T) concentrations from the muscle tissue of 22 females and 34 males landed in the New England fishery from June-December 2014-2015. These results suggest the hormone profiles between males and females are different, with females having a higher concentration of E2 (422+148pg/g) compared to males (213+87pg/g), while males’ T concentration is higher (1283+211pg/g) than females (539+127pg/g). Based on these results, the levels of reproductive hormone were used to develop a method for sex determination by comparing the ratio of T:E2. When applying the method to 111 samples of unknown sex collected from 2014-2015, a sex ratio of 1.5:1 males to females was established, which showed seasonal hormone fluctuation between the sexes. The present investigation demonstrates that skeletal muscle tissue is an effective substrate for determining the reproductive characteristics of Atlantic Bluefin Tuna.
Gahagan, Benjamin1 and Michael Bailey2. Impediments to restoration of American Shad (Alosa sapidissima) in the Charles River.
1Massachusetts Division of Marine Fisheries, 2United States Fish and Wildlife Service Central New England Fish and Wildlife Conservation Office
Since 2006, Massachusetts Division of Marine Fisheries and the United States Fish and Wildlife Service have worked cooperatively to restore American shad to the Charles River in Boston, MA USA. Surveys for spawning adults in the years 2012-2014 indicated low returns related to larval stocking numbers. To better understand restoration issues we conducted an acoustic telemetry study. Adult shad were collected using a boat electrofisher and acoustic tags were surgically implanted in the springs of 2015 (n=46) and 2016 (n=52). We observed limited mortality and a degree of fallback as a result of tagging. In both years tagged shad displayed pronounced diel movements as they attempted to navigate upstream passage barriers. No tagged fish were detected above the Watertown Dam (rkm 17), the first fishway on the river. Tagged shad attempted to pass this fishway for 2 to 46 days (mean = 16.9) before expiring or attempting to emigrate from the Charles River. Downstream transit was rapid, followed by delays of 1 to 15 days (mean = 5.02) at the locks associated with New Boston Dam in Boston Harbor. These two structures appear to cause delays and perhaps increase mortality for American shad attempting to spawn in the Charles River and are likely impediments to population restoration. In both years a significant percentage (2015=41%, 2016=59%) of tagged fish successfully exited the river and a subset of these shad were detected making northwards post-spawning movements, although no shad tagged in 2015 were detected in the Charles River in the spring of 2016.
Gardner, Lynette1. Evaluation of upstream passage of American Eel at the Turners Falls Project.
1 Kleinschmidt Associates, Essex, CT
To determine the best place to install upstream eel passage facilities, Kleinschmidt Associates conducted a two-year study (2014-2015) to investigate the route of upstream eel migration at the Turners Falls Project located on the Connecticut River in Massachusetts. In 2014, study objectives were to identify areas where eel congregated and to determine whether there are suitable sites to construct permanent eel passage structures. During this initial study year, 13 sites were surveyed on eleven nights each between June 11 and October 9, 2014. The approximate number of eels, the date and time of survey, eel behavior, and environmental conditions (e.g., weather, leakage, discharge) were recorded. The results of the surveys were clear as 94% of the 6,263 total eels recorded during the study period were observed at the Turners Falls Spillway Fish Ladder. Based on the results of the 2014 study, three temporary eel ramp traps were deployed in 2015 to investigate passage potential and eel abundance. The ramp traps were operated continuously between July 9 and November 2, 2015. The majority of the eels (88%) were collected at the Spillway Fish Ladder, a result that was consistent with the 2014 results. The study results were explicit in identifying that the most viable location for permanent upstream eel passage is at the Turners Falls Spillway Fish Ladder.
Goclowski, Matthew1, Tracy Maynard1, and Kevin Nebiolo1. American Shad spawning and spawning habitat in the Massachusetts portion of the Connecticut River.
1 Kleinschmidt Associates, Essex, CT
American shad (Alosa sapidissima) is an anadromous species that spawns in rivers along the Atlantic Coast from Florida, USA up to Newfoundland, Canada. Historic records indicate that American shad may have spawned as far North as Bellows Falls, Vermont on the mainstem Connecticut River. As part of a relicensing study, we used night-time visual and aural surveys to identify shad spawning locations and to assess spawning activity from the Vernon Dam tailwater (at river kilometer 228.4) to the Route 116 Bridge (river kilometer 176.1) in Sunderland, Massachusetts between May 13th and June 22nd, 2015. When groups of spawning shad were encountered, observers delineated the approximate extent of spawning habitat utilized by shad, recorded a suite of environmental variables to describe each habitat, and recorded the number of splashes that occurred within a 15-minute interval as an index of spawning activity. Spawning was observed at temperatures between 15.6 to 20.2°C and generally occurred in run and riffle habitats over gravel and cobble substrates. The effects of water temperature, flow, photoperiod, and time-after-sunset were assessed with multiple regression. Photoperiod appeared to be the biggest driver influencing spawning activity.
*Hammer, Lars1 and James Sulikowski1. The importance of the Saco River Estuary to Winter Flounder (Pseudopleuronectes americanus) life stages.
1University of New England, Biddeford, ME
Due to the effects of overfishing and habitat loss, Winter Flounder stocks have drastically declined since the 1980s. Although strict fishing regulations have stabilized populations, they are still below sustainable harvesting levels. In order to better manage and further promote the rebuilding of Winter Flounder stocks, essential fish habitat (EFH), such as nursery grounds and spawning areas, need to be identified. While previous EFH have been documented in the southern most US range of the species, very little information has been gathered in their northern most US range. Previous studies have suggested the Saco River Estuary System (SRES), in southern Maine, has the potential to serve as a nursery ground for Winter Flounder based on the presence of YOY and juvenile individuals. However, the extent to which Winter Flounder utilize the SRES needs to be addressed. In order to assess the importance of this northern estuary to Winter Flounder, a multifaceted study was initiated in 2016. Thus far, a total of 61 beach seines and 17 otter trawls have been conducted between May and August. Fish captured ranged in size from 25mm-400mm TL. Flounder captured in seine nets had an average total length of 53.3mm+-25mm, while flounder captured by otter trawling averaged 156.8mm+-80mm. These methods yielded CPUE’s of 0.31 (fish/seine) and 0.15 (fish/minute towed) respectively. Based on the wide size distribution range of sampled specimens, it would appear that this estuary not only has value as a nursery ground, but for other life history stages as well.
Harnish, Ryan1, Alison Colotelo1, Gary Johnson2, Zhiqun Deng1, and Marshall Richmond1. Biologically-based design and evaluation of hydro-turbines.
1Pacific Northwest National Laboratory, Richland, WA, 2Pacific Northwest National Laboratory, Portland, OR
The US Department of Energy’s Biologically-Based Design and Evaluation (BioDE) Initiative is providing advanced technologies for biologically-based design, operation, and evaluation of hydro-turbines to optimize the biological performance of hydropower. The technical approach for BioDE involves integration of experimentally-derived dose-response relationships, design tools for predicting biological performance, and evaluation tools for empirical measurements. Lab experiments are conducted to establish statistically rigorous relationships between physical stressors and responses of priority fish species, such as species listed under the Endangered Species Act. Sensor Fish, an autonomous multi-sensor device that measures certain physical conditions fish experience during turbine passage, are used along with computational fluid dynamics models and hydraulic measurements from laboratory tests to estimate the location, frequency of occurrence, and magnitude of stressors in the turbine environment. These data are integrated with dose-response relationships obtained from the laboratory studies to index the biological performance of the turbine. The resulting biological performance measures are used by the hydropower community (plant owner/operators, turbine manufacturers, regulators, and resource agencies) to select designs and operations that meet both power generation and fish passage criteria. Novel acoustic telemetry systems and dam passage survival models provide empirical measures of turbine passage survival that can be used to validate biological performance indices from BioDE. This presentation will provide a review of the approach, methods, and technologies used to evaluate the biological performance of hydro-turbines, including examples of their implementation.
Haro, Alex1,2. Past, present, and future of eel passage in the Northeast: A 35-year perspective
1S.O. Conte Anadromous Fish Research Laboratory, 2U.S. Geological Survey
Prior to 2000, upstream and downstream passage of American Eels in North America received relatively little attention. Although advances in upstream passage were being made in Europe, management and protection of eels in the US was a low priority. Successful State and grass-roots efforts to provide upstream passage at small dams, coupled with documented declines in eel populations and two Endangered Species listing petitions motivated new interest in provision of passage for eels, and development of management plans that identified passage and access to habitat as critical areas of restoration effort. Presently, upstream passage technologies have been refined and can be implemented with some effectiveness at most sites; downstream passage remains technically problematic. This presentation will review the progression of passage technology development and remaining issues and problems of eel restoration programs over one researcher’s 35-year span of experiences with one of the Northeast’s most enigmatic yet poorly understood fishes.
He, Pingguo1. Research on fish behavior and conservation engineering related to marine capture fisheries: Past, present, and future
1University of Massachusetts Dartmouth, North Dartmouth, MA
World marine capture fisheries are at a critical juncture. On the one hand, many of the world’s fish stocks are overfished, resulting in decreased quota and landing. On the other hand, conservation of protected species and sensitive ecosystems requires that fishing gears and their operation cause minimal collateral impact. How to reconcile conservation and sustainable exploitation requires better understanding of fish capture processes, especially behavior of fish during fish capture. This presentation will review research on fish behavior and conservation engineering related to marine capture fisheries in the North Atlantic during the past fifty years, discuss current issues facing the capture fisheries, and future challenges related to management and sustainable utilization of marine fisheries resources and sustainability of ecosystem. The talk will include notable scholars in fish behavior research and their contributions, major technological advances, conservation issues, and trends in behavioral and conservation research. The presentation will provide examples on how advances in our understanding of fish behavior and development of fishing technology may contribute to sustainable exploitation of fisheries resources with minimal collateral impacts to the ecosystem.
*Hodgdon, Cameron1, James Sulikowski1, Woon Yuen Koh1, Jeri Fox1, and Craig Tennenhouse1. Shortnose Sturgeon in the Saco River Estuary: An assessment of critical habitat
1University of New England, Biddeford, ME
The Shortnose Sturgeon (SNS) (Acipenser brevirostrum) is an endangered fish species that migrates between large river systems along the U.S. east coast. Despite its endangered status, our understanding of the species’ ecology is limited, especially in regards to the importance of smaller river systems to their recovery. The Saco River watershed represents a smaller system and is a midpoint between larger rivers of New England known to serve as essential fish habitat for SNS. However, prior to 2010, SNS were undocumented within the Saco River. Since then, 90 SNS have been captured, of which 27 were fitted with acoustic tags and monitored. Preliminary data suggests that 77 percent of tagged SNS appear to aggregate in the western-most portion of the tidal reach, closest to the dam. In 2016, the collection of abiotic data was coupled with the acoustic tagging study in an effort to establish which environmental parameters are most influential to the observed aggregations. Temporal and spatial variances of temperature, salinity, dissolved oxygen, acidity, substrate type, and water depth were monitored within the river from June to December with HOBO conductivity loggers and YSI instruments. These 6 parameters were ranked by significance they have influencing Shortnose Sturgeon movements within the river by way of multivariable regression analyses. Preliminary results suggest that salinity is the most influential abiotic factor of the 6. Further rankings and trends are being identified and will be presented at the AFS SNEC Conference.
Kahn, Desmond1. Management of a top inshore predator: Differing goals of recreational and commercial fishers of Atlantic Striped Bass and the unforeseen impacts on other fisheries.
1Desmond M. Kahn- Fisheries Investigation, 916 Rahway Drive, Newark, DE 19711
Striped Bass are produced in Mid-Atlantic estuaries, then migrate into New England waters in summer. They are the only inshore teleost in the Northeast that attains a fabled big game status for the recreational fishery; they also serve an economically important commercial fishery. After a crash in the 1980s attributed variously to acid rain/water quality and overfishing, striped bass recovered by the mid-1990s. Conservative management driven by recreational interests seeking high catch rates and large sizes brought the stocks to unprecedented abundance by the 2000s. High bass predation has been linked to severe declines in fisheries for weakfish, American shad and river herring. The Chesapeake Bay resident male stock, at a high density, has suffered starvation and an epidemic of Mycobacteriosis. Despite high spawning stock biomass, the Chesapeake Bay stock also failed for seven years to produce a dominant year class until 2011, leading to a slow coast wide decline in abundance. Due to their political dominance of the management process, recreational anglers have driven a 25% cut in commercial quotas, despite the dominant 2011 year class now beginning to recruit to the coastal fishery. Having lost the fisheries for weakfish and American shad, commercial baymen have few alternative finfish targets.
*Kasper, Jacob M.C.1, Amanda Caskenette2, Jason Vokoun1, and Eric T. Schultz1. Sound fisheries management: A regional stock assessment for Tautog.
1University of Connecticut, 2Fisheries and Oceans Canada
The Atlantic States Marine Fisheries Commission (ASMFC) Tautog management board approved a regionalized stock assessment for Tautog, a chronically overfished coastal species. Under this assessment, Long Island Sound (LIS) is a separate region. In a collaboration between the ASMFC, state agencies, and the University of Connecticut, three decades of data on regional demography and fishing activity were assimilated from state and federal databases into a statistical catch-at-age stock assessment. The assessment has been approved and accepted by the Tautog Management Board. Results indicate that Tautog in LIS have been overfished and overfishing is occurring. We are now developing regulatory scenarios designed to reduce harvest with the goal of achieving target levels of fishing mortality and spawning stock biomass by 2020.
*Langan, Joe A.1, Gavino Puggioni2, and Jeremy S Collie1. Evidence of spatiotemporal skew in the observed sex ratio of Winter Flounder in Narragansett Bay, Rhode Island.
1University of Rhode Island Graduate School of Oceanography, Narragansett, RI, 2University of Rhode Island, Kingston, RI
Sex-specific life history characteristics and spatial distributions are viewed as important considerations for the understanding of fish population dynamics. Although the sex ratio for many populations is expected to be relatively invariant, recent evidence suggests that this assumption is not always accurate. Winter Flounder (Pseudopleuronectes americanus) in southern New England and the Gulf of Maine, for example, have been observed to exhibit strongly female-skewed sex ratios around spawning that are thought not to be present during other seasons. However, data from the University of Rhode Island Graduate School of Oceanography weekly fish trawl survey in Narragansett Bay, Rhode Island (1985-Present) indicate further variability in the recorded sex ratio of this species over spatial, seasonal, and inter-annual scales that have not been previously described. This study used time series analysis methods to investigate these patterns and gain insight into the causes influencing the observed sex ratio of Winter Flounder in Narragansett Bay. The results of this modeling suggest that winter water temperature influences both apparent sex-specific movement patterns and time-delayed sex ratio variability through its known impacts on recruitment. While more in-depth data collection will be required to fully characterize such dynamics, these findings represent a step toward a more nuanced understanding of how Winter Flounder utilize habitats and interact with their environment around which targeted management measures may be developed to promote population recovery.
*Long, Michael1, Theodore Castro-Santos2, Adrian Jordaan1, and Chris Sutherland1. Dynamic detection range and efficiency of acoustic receivers based on transmitter distance and environmental conditions.
1University of Massachusetts, Amherst, MA, 2USGS S.O. Conte Anadromous Fish Research Center, Turners Falls, MA
Acoustic telemetry is widely used to monitor occupancy and movements of aquatic animals. However, detection ranges and efficiencies can vary as a function of environmental parameters, leading to potentially biased interpretations of data. An existing acoustic telemetry study on horseshoe crab movements in Wellfleet Harbor, Massachusetts provided an opportunity to examine detection ranges and efficiencies of acoustic receivers. 15 Vemco V13 acoustic transmitters were deployed within an array of 20 Vemco VR2W acoustic receivers over 3 test sessions. 5 transmitters were deployed per session at varying distances away from a reference receiver; duration of transmitter deployments ranged from 2-9 days. We used linear regression models to quantify the effects of transmitter distance from receiver, wind speed, wave height, water temperature, tidal height, and water depth on detection efficiencies in all sessions. Detection ranges varied from 50-1,500 meters and efficiencies varied from 0-100%. These results have potential to provide insight for future acoustic telemetry studies to advance telemetry analyses beyond presence and absence only data. Modeling detection ranges and efficiencies in future acoustic telemetry studies can improve estimates of animal occupancy and movement by reducing bias in analyses.
Lucey, Sean M.1 and Sarah K. Gaichas1. An Ecopath model of the Georges Bank Ecological Production Unit.
1Northeast Fisheries Science Center, Woods Hole, MA
Ecosystem based fisheries management is inherently place-based. The Northeast Fisheries Science Center has developed four ecological production units (EPU) that will serve as a spatial footprint for ecosystem-based management actions. The first EPU to undergo management strategy testing is the Georges Bank EPU located just off the coast of New England. In order to test various management strategies there will need to be a robust operating model of the area. One candidate model is a mass balance representation of the ecosystem commonly parameterized using the Ecopath with Ecosim modelling software. There is an existing Ecopath model of the region that contains highly aggregated species groups. This study updates that work with a more disaggregated box structure. It was also implemented using the Rpath package which is an R implementation of the classic EwE software. This model will be used as an operating model for testing various ecosystem strategies in an MSE framework.