Malvezzi, Alex¹. Assessment of adult Sea Lamprey spawning in the Connecticut River.

¹Kleinschmidt Associates, Essex, CT

The life cycle, habitat preferences and behavior of the adult oceanic stage of the Sea Lamprey, Petromyzon marinus, are not well understood.  As an anadromous species, their spawning behavior and habitats in the Connecticut River are vastly understudied.  In support of hydroelectric relicensing efforts, the aim of this study was to evaluate spawning of Sea Lamprey in the Connecticut River.  Forty lamprey were radio tagged and released in two locations during the early and mid-portion of their spawning run to identify spawning locations via mobile tracking.  Twenty-nine lamprey nests (redds) were selected in five regions within the Project area to be monitored throughout the 2015 spawning season.  Several parameters (water velocity, water depth, substrate characterization, presence/absence, and water quality) were measured weekly at each lamprey redd from June 12 to July 31, 2015.  Five redds were capped after visual confirmation of spawning/nesting activity to characterize spawning success by collecting any emerging larval lamprey, or ammocoetes.  Using depth, velocity and substrate data, composite suitability index maps of the project area were produced by way of existing habitat suitability index (HSI) criteria for spawning Sea Lamprey developed as part of an Instream Flow study conducted in the early 1980s.  Our findings indicate that Sea Lamprey utilize spawning habitats with greater depths and coarser substrates than those in the referenced HSI criteria.

 

McDermott, Sean¹, Christine Lipsky², and Tim Sheehan³. Diadromous fish and their predators in coastal Maine: Past, present, and future.

¹Greater Atlantic Regional Fisheries Office, Gloucester, MA, ²Northeast Fisheries Science Center, Orono, ME, ³Northeast Fisheries Science Center, Woods Hole, MA

Diadromous fish species, including River Herring (Alosa pseudoharengus; A. aestivalis) and American Shad (A. sapidissima), are known to have been historically important prey items for Atlantic Cod (Gadus morhua) and other groundfish species in coastal Maine. Anthropogenic factors (e.g. harvest, dams, water quality degradation) have resulted in a major decline in diadromous fish populations.  Researchers have hypothesized that this decline has exacerbated similar declines in groundfish stocks over the past 200 years. Recent large-scale restoration efforts in Maine have enhanced the abundance of diadromous fish species in nearshore waters, increasing their numbers by several orders of magnitude. Several assessment surveys have been conducted to evaluate diadromous species responses to large-scale river restoration projects, and to evaluate the effect that changing prey resource availability may have on groundfish species distribution and abundance. Restoring a healthy diadromous prey species assemblage in coastal Maine may assist in rebuilding depleted groundfish populations regionally, given the close historical predator-prey relationship between the two groups of fish.

 

McDowell, Christopher¹, Gerald Leonard², Brian Eltz², Justin Davis³, Eileen O’Donnell¹, Robert Jacobs¹, Timothy Barry². The Past, present and future of Walleye management in Connecticut.

¹CT DEEP IFD, Marlborough, CT, ²CT DEEP IFD, Harwinton, CT, ³CT DEEP IFD, Old Lyme, CT

Walleye (Sander vitreus) stocking in Connecticut dates back to the early 1900s. During a 47-year period (1911-58), approximately 77 million Walleye fry were stocked into 16 Connecticut lakes and the Connecticut River by the State Board of Fish and Game. These efforts produced fishable Walleye populations; however, the program was deemed unsuccessful and was discontinued because no self-sustaining populations were created. In 1993 the Connecticut Department of Environmental Protection initiated a put-grow-and-take Walleye Management program by annually releasing 4-6 inch fingerlings into select Walleye Management Lakes (WMLs) purchased from vendors located in the Midwest. Presently, Connecticut’s Walleye fisheries are regulated by a statewide 18-inch minimum length, two-fish-per-day limit. Though there are still no documented self-sustaining populations in the WMLs that would allow for the discontinuation of stocking to create a fishery, the program is deemed successful. Within surveyed WMLs, anglers are consistently in favor (52-89%) of this program and regularly submit proof of catching qualifying (23-inches or five pounds) Walleye for a Trophy Fish Award (151 awards distributed between 1997-2015).  Overall, better Walleye fisheries are found in the Western portion (West of the Connecticut River) of the State. This may be linked to the fact that these lakes lie in a different geological strata and therefore have different water chemistry, water temperatures and forage species. Because Connecticut’s Walleye fisheries are important, investigations into how to maintain, as well as enhance, this program will continue. Currently, adjustments to fingerling stocking rates and sizes is being investigated at our struggling WMLs.

 

McGuire, Christopher¹, Douglas Zemeckis², Micah Dean³, William Hoffman³, Annamaria Izzi⁴, Sofie Van Parijs⁴, Mark Baumgartner⁵, Leila Hatch⁶, and Steven Cadrin¹. Identifying the distribution of Atlantic Cod spawning activity to inform fishery management in the western Gulf of Maine.

¹The Nature Conservancy, Boston, MA, ²U. Mass Dartmouth SMAST, ³MA Division of Marine Fisheries, ⁴Northeast Fisheries Science Center, ⁵Woods Hole Oceanographic Institution, ⁶Stellwagen Bank National Marine Sanctuary

Rebuilding the Gulf of Maine stock of Atlantic Cod (Gadus morhua) has been much slower than anticipated. Many historical spawning components have been depleted, which has reduced stock productivity and stability. In response, fishery managers have implemented closures to protect cod spawning aggregations. The objective of this project was to identify the spatial and temporal distribution of cod spawning activity during the winter to inform future fishery management decisions in the western Gulf of Maine. Through effective collaboration among state, academic, federal, and NGO scientists, and commercial fishermen, this study successfully utilized multiple acoustic technologies to identify Cod spawning distribution during three consecutive winter spawning seasons, from October 2013 through March 2016, in Massachusetts Bay. Based on a combined synthesis of the acoustic telemetry and passive acoustic monitoring data, from both fixed station and mobile autonomous glider deployments, the temporal distribution of Cod spawning activity was shown to have some inter-annual variability, with spawning activity primarily occurring during early November through January with a peak in mid-December. The spatial distribution of spawning activity was generally consistent among years and concentrated in areas deeper than 50 meters. Our scale of observation annually increased and permitted documentation of multiple hotspots of spawning activity centered in an area in the northern section of the Bay, west of Stellwagen Bank.  The findings, when published, will be shared with fishery managers to inform future management actions to protect spawning Cod while enabling harvest of other target stocks.

 

Mrakovcich, Karina L¹ and Lucy Vlietstra¹. Fishes of the Thames River Estuary, Connecticut:  Long-term trends in relation to sea surface temperature.

¹U.S. Coast Guard Academy, New London, CT

The Thames River, Connecticut, is a salt wedge estuary located on Long Island Sound. It supports a diverse assemblage of commercially and recreationally important fish species and is subject to a variety of human impacts. To study long-term shifts in the fish community concurrent with environmental change in the region, U.S. Coast Guard Academy instructors and their students have been collecting bottom trawl data on a weekly basis from August to October for >20 years. Field methods have been remarkably consistent over time, yielding a valuable long-term data set unique to the region. In this study, we focus on observed trends in finfish relative abundance across four decades: 1970s, 1990s, 2000s, and 2010s. Overall, we found an overall shift of dominant communities from cold-adapted temperate species to warm-adapted temperate species in the estuary. For example, the relative abundance of species changed over time from Winter Flounder (Pseudopleuronectes americanus), dominant in the 1970s and 1990s, to Scup (Stenotomus crysops), dominant in the 2000s and 2010s. In addition, surveys conducted between 2003 and 2016 detected an increase in the proportion of fish species typically found in subtropical waters.  Other studies conducted in nearby estuaries have observed a warming trend in surface waters, and our results suggest a shift in finfish abundance in the Thames River estuary consistent with this trend.  Understanding the fluctuation of finfishes and possible links to climatic factors and other sources of environmental variability is important for the effective management of fisheries.

 

Munroe, Daphne¹, Jason Morson¹, and Ryan Harner¹. Sex ratios of Summer Flounder discards in the recreational fishery.

¹Haskin Shellfish Research Laboratory, Rutgers University

The most recent peer review of the Summer Flounder stock assessment offered support for the application of a sex-based population model.  To implement a fully sex-disaggregated model however the sex composition of the catch must be known or assumptions must be made about the sex-specific selectivity curves of the fisheries and their stability in space and time.  Recreational landings are 95% female, but no information is available on the sex composition of discards for this fishery.  To address this gap in available data, the sex composition of the entire Summer Flounder catch (landings and discards) was evaluated during the recreational season aboard fishing vessels (49 trips total) in New Jersey, New York, and Rhode Island.  While fish above the minimum landing size (46cm) were predominantly female as has been reported previously, fish caught below the minimum landings size were predominantly male.  Fish under the legal-size limit made up 84% of the total catch.  Given 10% of these discards are assumed to die, we estimated that 74% of the recreational fishing mortality (landings plus dead discards) is directed at the female portion of the stock.  In addition, male fish were more common at a given size in deeper water and at higher latitudes.  This information should prove useful in both the continued development of a sex-structured assessment model for this species and in evaluating alternative management strategies and their influence on sex-specific fishing mortality.

 

Murphy, Brian D¹, Stephen R Gephard², and Mindy M Barnett¹. Engineering and design features of a culvert sliplining project in Connecticut to facilitate Brook Trout passage.

¹Department of Energy and Environmental Protection (CTDEEP), Inland Fisheries Division, Marlborough, CT 06447, ²CTDEEP Inland Fisheries Division, Old Lyme, CT 06371

Many aging culverts that convey streams under Connecticut highways are being rehabilitated with “sliplining”, a technique that involves placement of a smaller diameter culvert within the larger failing culvert. In 2015, Inland Fisheries worked with the Department of Transportation to design and implement fish passage solutions at several slipline projects. One project located on a Tributary to Lyman Brook (TLB) will serve as a demonstration site to evaluate design features and passage performance for a native Brook Trout population via passive integrated transponder (PIT) tag monitoring. The TLB project involved sliplining twin 5 ft. diameter culverts that were: 262 ft. in length, slope of 4.5% and outlet perch of 1.5 ft. A concrete pool/weir fishway was constructed at the outlet for fish to ascend the perched culvert. The fishway culvert was retrofitted with an angled corner baffle system. Mean daily flows are directed into the baffled culvert by an inlet diversion wall. Brook Trout movement will be studied by stationary PIT tag antenna systems installed below/above the culvert pre-, during and post-fall spawning from 2016-2018. Mobile tag searches will also be conducted. Preliminary results of PIT tag monitoring in 2016 will be discussed that include passage transit times, efficiency and daily movement patterns. Information and lessons learned from this sliplining project will help guide the development and design of fish passage features at future projects. If culvert modifications cannot successfully pass fish, future projects may require offsite mitigation.

 

*Nathan, Lucas R¹, Amy B Welsh², and Jason C Vokoun¹. A tale of two watersheds: exploring riverscape drivers of Brook Trout genetic structuring.

¹University of Connecticut, Storrs, CT, ²West Virginia University, Morgantown, WV

The dispersal of fish and other aquatic organisms is influenced by a diverse array of natural and anthropogenic factors.  Although species like Brook Trout are commonly assumed to be predominately residential, infrequent dispersal at larger scales can play substantial roles in promoting long term population viability by maintaining genetic diversity.  Identifying features on the landscape that limit connectivity, therefore, is an important and necessary step towards designing effective conservation actions.  To evaluate the potential influence of riverscape variables on Brook Trout population structuring, we collected genetic samples from over 2,000 individuals across two Connecticut watersheds each spanning approximately 1000 km2.  The two watersheds were selected based on contrasting network architectures, with one having a more classic dendritic pattern while the other was a network of parallel, linear subwatersheds. Using a suite of genetic techniques, we documented genetic relatedness and quantified dispersal among headwater stream populations.  We then used landscape genetic analyses to identify the combination of anthropogenic and natural variables potentially driving genetic structuring.  Results indicated metrics of genetic differentiation (Fst) between neighboring streams ranged ten-fold over comparable stream distances and a combination of anthropogenic barriers and natural features influenced such relationships.  The results of this study will be used to identify features limiting connectivity across broad spatial extents which can be targeted for conservation actions. This type of empirically-informed approach will allow for more biologically relevant upstream/downstream and among stream restoration prioritization strategies, moving beyond simply attempting to maximize miles upstream of a barrier recommended for removal.

 

Nebiolo, Kevin¹. Analysis methods for evaluating passage of adult American Shad at the Turners Falls and Northfield Mountain Projects.

¹Kleinschmidt Associates, Essex, CT

An analysis on the migration and emigration of adult shad throughout the Connecticut River was conducted as part of a FERC relicensing study. In 2015, FirstLight conducted a combined radio and PIT telemetry-based study to investigate the behavior, routes of passage, passage success, survival, and delay of American Shad as they encounter the project infrastructure 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. We first created a telemetry network consisting of receivers as nodes, and possible passage pathways of edges.  Then, a mix of methods assessed each objective, including the classic Cormack-Jolly-Seber open population mark recapture model to assess ladder passage and identify bottlenecks, Cox Proportional Hazards regression modelling to assess project induced delay, and Multi-State Markov models to assess route of passage and attraction.  A subset of the analyses is presented herein.

 

Nelson, Gary A¹. Bias in catch curve analysis of age-frequency data from fisheries-independent surveys.

¹Massachusetts Division of Marine Fisheries

Catch curve analysis is a common way to estimate total mortality (Z) from a single sample of age-frequency data taken from a fish population. In cases where catch age compositions are not available for exploited stocks, researchers often use age data collected from fisheries-independent surveys. A basic requirement of all estimators (e.g., Chapman-Robson, Heincke, linear regression etc.) is that individuals are collected via simple random sampling to meet the independence assumption of the underlying probability models. In reality, fish are not collected by simple random sampling during fisheries surveys, but rather by random cluster sampling because individuals are captured in groups or cluster by the survey gear. Cluster sampling creates non-independence of observations. If the common methods are applied to age frequencies from cluster sampling, estimates of total mortality and associated variance will likely be biased. In addition, fish for ageing are often subsampled from a tow or haul and this adds extra-variation to estimated age frequencies which is not accounted for by the common estimators.
In this study, I explored the impacts of clustering and subsampling on the performance of catch curve estimators through simulation.  I found that the least biased estimates of Z were produced by the Chapman-Robson and Poisson regression methods, and that the newly-introduced random-intercept Poisson mixed model, which usually performs better than the other methods when assumptions are violated, performed very poorly when subsampling occurred.

 

Nieland, Julie¹ and Timothy Sheehan¹. Assessing the effects of dams, marine and freshwater survival, and hatchery supplementation on Atlantic Salmon recovery in the Penobscot River, Maine.

¹NOAA Fisheries, Northeast Fisheries Science Center, Woods Hole, Ma

Atlantic salmon populations in Maine are listed as endangered under the Endangered Species Act. Marine survival and dams are considered to be two of the biggest impediments to increasing these populations, but freshwater survival and hatchery supplementation will also affect their recovery potential. We used a population viability analysis of Atlantic salmon in the Penobscot River, Maine, to assess the effects of dams, marine and freshwater survival, and hatchery supplementation on the demographics of this population. We ran various scenarios to evaluate the influence of these four factors on recovery of Atlantic salmon in the Penobscot River watershed. Increased marine survival led to greater increases in abundance than increased freshwater survival, and, as expected, hatchery supplementation and fewer dams in the watershed helped the population reach recovery when marine and freshwater survival rates were low. Although increases in marine and freshwater survival will both be necessary for this Atlantic salmon population to recover, new management options for increasing marine survival appear limited. Therefore, restoration efforts should focus on increasing the number of salmon coming from the freshwater environment, which means increasing survival during juvenile life stages, minimizing dam impacts, and continuing hatchery supplementation to increase the recovery potential of the population. Quantifying the impacts of these factors on the recovery potential of Atlantic salmon in the Penobscot River can help inform management strategies and frame expected outcomes for potential management options across the species’ U.S. range to facilitate recovery.

Nye, Janet A¹, Emily Markowitz¹, Adam F Younes¹, and Maxwell Silverstein². Does overwintering survival determine recruitment of black sea bass on the New England US continental shelf?

¹School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, ²Duke University, Durham, NC

As climate change induces the large-scale redistribution of fishes, it is critical to understand the mechanisms that cause these shifts to allow us to predict their future abundance and distribution. In the Northeast US, the northward expansion of black sea bass has been documented and it will likely become an important fishery in the Gulf of Maine in the near future.  One mechanism that has been proposed to explain the northward expansion of black sea bass has been that overwintering mortality has decreased in recent years because of warmer water temperatures.  We tested this hypothesis by first developing a winter survivorship model as a function of temperature, salinity and fish size for black sea bass in the laboratory.  We then applied this model to the Northeast US shelf using bottom temperature and salinity hindcasts from a Regional Ocean Modelling Systems (ROMS) for 1967-2007.  We found that recruitment only in some state surveys was correlated to a simple measure of the coastwide winter suitable habitat.  Furthermore, each year there was a consistent region of suitable winter habitat to which black sea bass could migrate to overwinter and survive.  Even in some places in the Gulf of Maine, conditions would allow survivorship of black sea bass in most years.  We discuss several reasons for the weak relationship between recruitment and our index of total suitable winter habitat and hypothesize that the increase in the length of the summer-fall growing season has improved survival of juvenile black sea bass in the northern US.

 

Rillahan, Chris¹ and Pingguo He¹. Reducing flounder bycatch in the Georges Bank Haddock Fishery: Application of a modified European grid system.

¹SMAST University of Massachusetts Dartmouth

Georges Bank (GB) haddock is one of the few robust groundfish stocks in New England.  GB haddock is a fully rebuilt stock which is not overfished and is not experiencing overfishing. However, the exploitation of the haddock resource is dependent on the status and quota allocations of bycatch species.  Currently the populations of flatfish species, including yellowtail and windowpane flounder, are significantly depressed, making them quota-limiting species.  To reduce the catch of these fish, a grid system with horizontal slots placed in the extension of a commercial demersal trawl was evaluated to exploit the morphological differences between groundfish (including Atlantic cod and haddock) and flatfish.  The grid system was designed to allow selective escape of flatfish and juvenile groundfish.  To evaluate their performance, comparative fishing trials were conducted on Georges Bank with the commercial fishing vessel F/V Hera.  Alternating tows were conducted with and without the grid system.  The result of twenty six tow pairs showed a 51.3% reduction in the catch rate of flounder, primarily winter flounder, and 29.4% reduction in skates, a major discard species. There was no significant reduction for Atlantic cod, the major round fish captured during sea trials. While the overall catch rate of haddock was reduced by 36.9%, the reduction was mainly associated with small fish below 47 cm fork length (19”).  Overall the use of this modular grid system may be a tool which will allow fishermen to quickly alter species and size selection properties on their nets to match their species quote and to reduce undersize fish.

 

Savoy, Tom¹. Sturgeon in Connecticut waters: an update.

¹CT Department of Energy and Environmental Protection

From 1984 through 2016, Connecticut Department of Energy and Environmental Protection staff collected 4,985 Shortnose and Atlantic Sturgeon.  All sturgeon were identified, examined, most were tagged and many selected for additional procedures (lavage, ageing and telemetry), roughly 15% of fish were recaptures.  Shortnose Sturgeon accounted for 52% of the catch.  Shortnose Sturgeon recaptures ranged up to 24 years between collections and many fish have been collected multiple times.  Mark recapture data document growth (length and weight) and systematic increases in the numbers of Shortnose Sturgeon in the lower Connecticut River.  Atlantic Sturgeon recaptures include many tagged out of State with coastal migrants recaptured from all 5 NOAA designated DPS’.  Atlantic Sturgeon tagged and recaptured in Connecticut waters document highly variable growth but averaged 0.31 mm FL/day for sub-adult fish.  Over 350 sturgeon were surgically implanted with ultrasonic transmitters for determining seasonal movement patterns and important habitats.  Passive acoustic receivers were deployed to document fish presence and movements.  Array size and configuration varied widely among years but over 10,000,000 detections have been collected.  Telemetry and recapture efforts documented high fidelity of Atlantic Sturgeon to and seasonal presence in Connecticut waters, some fish returning up to four years in a row.  Atlantic Sturgeon also annually entered the Connecticut River and traveled well above the salt wedge (rkm 26), some to river kilometer 84.  Genetic testing of 47 small Atlantic Sturgeon collected in 2014 documented a unique genotype suggesting a successful spawning in the Connecticut River.

 

Savoy, Tom¹, Jacqueline Benway¹. Connecticut River American Shad.

¹CT DEEP

A brief life history of the fish and the Connecticut River basin will be presented for background.  Restoring shad to river areas denied them were thought to enhance stock size by providing access to additional spawning and rearing habitat.  A CT River restoration target was 2,000,000 shad to the mouth and 50% over each dam.  A significant distinction of the Connecticut River population from many other Rivers was that from 1849 (first main stem dam completion at river kilometer 140) to 1975, the population persisted, sustained moderate sport and commercial fisheries and had a robust age structure.  Upstream fish passage of 20 to 60% of the annual run above the first dam since 1976 has resulted in no discernable large increases in population size.  In contrast, management efforts had significant negative effects by reducing both the percentage of repeat spawning shad and thus the number of age classes in the annual spawning run.  The stock is now primarily composed of virgin fish and is at greater risk of recruitment failure given dependency on few virgin year classes in the spawning population (currently 3 versus 5-7 historically).  Older year classes of repeat spawners had both higher fecundities and larger more viable eggs.  One or more poor consecutive year classes will reduce population size to levels well below the long term average and raises concern over long term population stability.   Year class failure is more likely with the truncated age structure and long term viability of the population is threatened.

 

*Snyder, Jacob¹, Christopher Murray¹, and Hannes Baumann¹. Maternal effects on offspring CO2 sensitivity in a coastal marine fish.

¹UCONN Avery Point Department of Marine Sciences

Many marine fish employ maternal provisioning as a strategy to better prepare offspring for changing environmental conditions. Whether maternal provisioning influences the sensitivity of fish early life stages to elevated CO2 conditions has yet to be determined.   We reared offspring batches derived from five female Atlantic silversides (Menidia menidia) under contrasting CO2 conditions from fertilization to 16 days post hatch and quantified six response traits, including growth and survival. For most traits, we found strongly divergent responses (expressed as log-transformed response ratios, lnRR) between batches, and subsequently used fatty acid (FA) profiles of the unfertilized eggs to test for associations with the observed lnRR’s. Multiple FA’s were positively correlated (20:1n9, 22:5n3, 15:0) with survival lnRR’s while others were negatively correlated (18:3n3, 18:4n3, 22:6n3) with length lnRR’s. Maternal investment has been shown to be highly important to offspring survival, and this study shows that variable egg provisioning by mothers with certain FAs may influence offspring sensitivity to high CO2 environments. Our study also suggested that ocean acidification experiments on fish early life stages need to be based on a large number of spawners in order to avoid biases resulting from individual maternal effects.

Staudinger, Michelle D¹, Kathy Mills², Nathan Rebuck³, Christy Hudak⁴, Adrian Jordaan⁵, Karen Stamieszkin⁶, Dan Pendleton⁷, Kevin Friedland³, Rubao Ji⁸, Andrew Allyn², Mila Calandrino⁵, Tony Diamond⁹, Zhixuan Feng⁸, Christine Feurt¹⁰, Walt Golet², Meaghan Henderson¹¹, Chrissy Hernandez⁸, Tom Huntington¹², Catherine Johnson¹³, Dave Johnson¹⁴, John Kocik³, Yun Li⁸, Matt Liebman¹⁵, Ivy Misna¹⁵, Owen Nichols⁴, Nick Record¹⁶, Anne Richards³, Tom Robben¹⁷, Jen Seavey¹⁸, Josh Stoll⁶, Jenny Sun², Andy Thomas⁶, Harvey Walsh³, and Keenan Yakola⁵. It’s about time: A synthesis of changing phenology in the Gulf of Maine Ecosystem.

¹Northeast Climate Science Center, Amherst, MA, ²Gulf of Maine Research Institute, ³NOAA Northeast Fisheries Science Center, ⁴Center for Coastal Studies, ⁵University of Massachusetts Amherst, ⁶University of Maine, ⁷New England Aquarium, ⁸Woods Hole Oceanographic Institution, ⁹University of New Brunswick, ¹⁰Univeristy of New England, ¹¹Stony Brook University, ¹²United States Geological Survey, ¹³Fisheries and Oceans Canada, ¹⁴Virginia Institute of Marine Science, ¹⁵United States Environmental Protection Agency, ¹⁶Bigelow Lab for Ocean Sciences, ¹⁷Connecticut Ornithological Association, ¹⁸University of New Hampshire

Climate change is causing species to shift their phenology, or the timing of recurring life events, in variable and complex ways. If phenological shifts differ among species, the result would be mismatches or asynchronies in food and habitat resources that impact individual fitness, population dynamics, and ecosystem function.  While climate change induced shifts in phenology have been well documented in terrestrial ecosystems, particularly relative to flowering plants and migratory song birds, studies of marine organisms have been limited to date. This presentation will provide an overview of the current understanding of changes in timing of recurring seasonal environmental and ecological events, as well as the implications of those shifts on regional management, conservation, and climate change adaptation strategies in the Gulf of Maine Ecosystem. Results highlight where we have sufficient evidence and observations to detect regional phenological shifts and where gaps remain.  While climate change is a likely factor influencing observed or inferred shifts in phenology, other direct and indirect mechanisms that can confound our detection of regional signals will also be discussed. A set of phenology-relevant recommendations that address bias and gaps in monitoring protocols will help identify where additional effort is needed to improve spatial and temporal resolution for specific variables and species of high conservation and management concern. We anticipate this comprehensive examination of shifting phenology will be useful to inform climate change adaptation strategies seeking to reduce uncertainty and sustain important natural resources in the Gulf of Maine region.

 

Sweanarton, John T¹ and Donald F Landers Jr¹. Long-term (1984-2015) trends in catches of incidental species from an experimental lobster trap survey in eastern Long Island Sound.

¹Dominion Resources Services, Millstone Environmental Laboratory, PO Box 128, Rope Ferry Rd, Waterford, CT 06385

Since 1984, catches of incidental fishes and invertebrates in 60 experimental lobster traps deployed from May to October around Millstone Power Station were recorded as part of a comprehensive ecological monitoring study.  While lobster catches have declined locally (and throughout southern New England), catches of other crustaceans increased during the study period (blue crabs, hermit crabs) or have fluctuated without any apparent trend (Jonah crabs).  Catches of fishes commonly found in traps (Cunner, Tautog, Scup) have also fluctuated without any obvious trend as have whelk catches.  Spider crab and rock crab catches have generally declined since peaks in the 1990s, similar to the trend in lobsters.  Incidental catch data provide another perspective on significant ecosystem changes observed in other aspects of this monitoring study (e.g., adult finfish and ichthyoplankton) as well as other studies in the region.

*Sweezey, Brett¹, Micah Dean², Benoit Hugues³, John Mandelman¹, and James Sulikowski¹. Determining post-release mortality for Atlantic Cod discarded in the Gulf of Maine lobster fishery.

¹University of New England, ²Massachusetts Division of Marine Fisheries, ³University of New Brunswick

Atlantic cod, Gadus morhua, has experienced heightened fishing-induced mortality since the 1990s leading to the lowest population abundances in recorded history. Although rigorous commercial and recreational limitations have been established in an attempt to restore this species, population levels remain at all-time lows. A potential issue affecting the recovery of cod populations is the unaccounted discard mortality experienced within Northwest Atlantic fisheries. With over 4 million fished traps, the lobster industry represents Maine’s largest fishery and has recently been suggested as a major contributor towards the increased mortality rates of cod within this region. For example, preliminary data suggests that discard rates as high as 1.32 cod/trip may exist. Additionally, recent evidence suggests individuals that experience multiple capture events may have elevated rates of mortality due to chronic stress. To evaluate the post release mortality of cod within commercial lobster gear, an acoustic array measuring 36 km2 was established off of Cape Porpoise. Data was collected from June to October 2016, resulting in 55 cod captured over 54 fishing trips (consisting of approximately 10,000 individual trap hauls). Acoustic transmitters were placed on 30 individuals, 28 of these cod were detected throughout the array, and three of which were later recaptured within lobster gear. Preliminary results indicate injury conditions upon capture ranging from absent (68%), to minor (20%), or deceased upon haul (12%). Discard mortality will be assessed by correlating vitality condition upon capture with the observed or absence of movement throughout the acoustic array.

 

Tableau, Adrien¹, Jeremy Collie¹, and Richard Bell². Understanding climate-induced changes in fish productivity to inform sustainable management.

¹Rhode Island University – Graduate School of Oceanography, Narragansett, RI, ²The Nature Conservancy, Narragansett, RI

Evidence is accumulating that climate change and variability are affecting the distribution, recruitment and production of marine fish species. Even so, it is difficult to distinguish climate signals from other processes, including mortality from fishing and predation. At the same time, annual catch limits must be specified without full understanding of these production processes. This study identifies changes in stock productivity for 20 managed fish species on the Northeast Shelf Large Marine Ecosystem with a Kalman filter approach. For each stock, biological reference points are used to define harvest control rules. Thus, time-varying biological reference points are calculated for stocks exhibiting changes in productivity. They are compared to constant reference points to determine their relevance for use in management. A second step consists of improving the prediction of productivity for each stock. For data-poor stocks, the approach of using the covariance with other stocks will be introduced. For stocks exhibiting a trended and/or climate-driven productivity, we offer a method to account for this shared information in the Kalman filter framework. For both approaches, we assess the performance of the productivity prediction to conclude on their respective value for management.

 

*Teffer, Amy¹, Kristi Miller², Steven Cooke³, Ken Jeffries⁴, Francis Juanes¹, Scott Hinch⁵. Incorporating infectious disease processes into our understanding of the impacts of multiple stressors on wild Pacific salmon.

¹Department of Biology, University of Victoria, Victoria, BC, ²Fisheries and Oceans Canada, Molecular Genetics Section, Pacific Biological Station, Nanaimo, BC, ³Fish Ecology and Conservation Physiology Laboratory, Carleton University, Ottawa, ON, ⁴Department of Biological Sciences, University of Manitoba, Winnipeg, MB, ⁵Pacific Salmon Ecology and Conservation Laboratory, Department of Forest Sciences, University of British Columbia, Vancouver, Canada

Like many migratory species, adult Pacific salmon encounter multiple stressors en route to spawning grounds, simultaneously carrying a diversity of infectious agents. Productivity of Pacific salmon in recent decades has declined concurrently with rising river temperatures and intense fisheries effort. Fisheries bycatch, a generally stressful and injurious event, and climate-induced high river temperatures likely influence the mechanisms of en route mortality by interacting with or enhancing infectious disease processes. To test this hypothesis, we collected adult Coho salmon from the Fraser River watershed, British Columbia and exposed them to gillnet entanglement at cool or warm temperatures. We non-lethally sampled gill tissue at the onset and periodically throughout a holding period of two weeks, and used high-throughput qPCR to characterize infectious agent intensity concurrently with host genomic immune responses. Survival was decreased at high temperature and following entanglement. Infectious agents showed variable responses to high temperature and entanglement, but infection intensity was generally enhanced in fish that died prematurely. Gene expression biomarkers of iron metabolism, osmotic stress, and wound healing in gill positively associated with entanglement, high temperature, mortality, and females. Our results demonstrate the importance of temperature, fisheries, and sex in understanding the disease processes of wild fish and the fitness consequences for semelparous species like Pacific salmon as river temperatures and fisheries demand continue to rise.

 

Tomicheck, Chris¹ and Rich Murray². Overview of development and construction of Shortnose Sturgeon passage protection at the Holyoke Dam.

¹Kleinschmidt Associates, Essex, CT, ²Holyoke Gas & Electric, Holyoke, MA

Holyoke Dam is the first dam fish encounter during their annual migration up the Connecticut River.  The owners of the Holyoke Dam, Holyoke Gas & Electric (HG&E) conducted over 10 years of research in cooperation with the Resource Agencies to address a permanent solution for downstream fish passage including, specifically, Shortnose Sturgeon. The first challenge for this project was gaining an understanding of the swimming behaviors of the Shortnose Sturgeon.  Until this project, little was known about passing Shortnose Sturgeon upstream and downstream of hydroelectric facilities.  First through flume studies, we were able to gain knowledge of swimming behaviors at varying intake rack velocities and attraction to bypass devices.  Once an understanding of the flow dynamics needed to attract and move Shortnose Sturgeon was developed, a series of computational fluid dynamic (CFD) models were created to model the desired flow fields at the Holyoke Dam.  Based on the results of the research, in 2015, HG&E installed a multi-million-dollar downstream fish passage system. Field evaluations of passage effectiveness are being conducted with Shortnose Sturgeon, juvenile and adult American shad and American eels. Interestingly after the Project was completed there was a surge in the number of Shortnose Sturgeon entering the upstream fish lift.  In 2016, 93 sturgeon entered and were successfully lifted which is a significant increase from the previous average of 3 Shortnose Sturgeon per year.

 

Turner, Sara M¹, Bradford C Chase¹, and Michael S Bednarski². Evaluating the effect of dam removal on yellow-phase American eel abundance in a Northeast U.S. watershed.

¹Massachusetts Division of Marine Fisheries, ²Virginia Department of Game and Inland Fisheries

The negative effects of dams and the benefits of dam removal for anadromous populations have been well documented. The effects of dams on catadromous Anguillidae may be less drastic, although documentation of the response of catadromous species to dam removal is limited. We developed a mark-recapture study design to estimate the abundance of catadromous American eel (Anguilla rostrata) within a small coastal watershed and to compare estimates of abundance before and after barrier removal. In the Mill River, Taunton, MA, two dams were removed, juvenile eel passage installed at another, and removal of the final is scheduled. Mark-recapture sampling and modeling methods were developed and applied in Lake Sabbatia, the source of the Mill River, over a four-year period from the initiation of restoration. Rectangular eel traps were found to have higher catch per unit effort than double-funnel traps used in previous studies, and a tag retention study found relatively high retention rates (97% overall). Abundances of yellow-phase American eels have increased with improved passage and recruitment to sampling gear during the study period. Dam removal could have substantial benefits to the coastwide stock of American eel, and methods to evaluate changes in abundances are important for management as well as restoration ecology and project selection.

 

Walsh, Harvey J¹, Jon Hare², Ken Able³, Thomas Grothues³, Jason Goldstein⁴, and Jeremy Miller⁴. A comparison of long-term oceanic and estuarine larval fish abundance between the Gulf of Maine and Mid-Atlantic Bight.

¹NOAA, Northeast Fisheries Science Center, Narragansett, RI, ²NOAA, Northeast Fisheries Science Center, Woods Hole, MA, ³Rutgers University Marine Field Station, Tuckerton, NJ, ⁴Wells National Estuarine Research Reserve, Wells, ME

Changes in climate and ocean conditions are topics of increasing importance because of the current and future implications of its effects, especially in marine ecosystems that support commercially important fisheries.  Distributional shifts have been documented for a number of species, for both adults and larvae, along the Northeast U.S. Shelf Ecosystem.  Many of the species that have shifted distributions use oceanic, shallow coastal, and estuarine environments for at least part of their life cycle.  Thus, the trends in long-term abundance among multiple locations along the Northeast Shelf can inform changes in distribution, including range expansions or contractions. The Northeast Fisheries Science Center (NEFSC) has been collecting shelf-wide concurrent ichthyoplankton and hydrographic data on the Northeast U.S. Shelf Ecosystem since the 1970s. The Rutgers University Marine Field Station (RUMFS) has been collecting larval fish ingressing into the Mullica River, Great Bay Little Egg Inlet (Mid-Atlantic Bight) since 1989. Finally, ingress sampling of larval fishes of the Webhannet River Estuary (Gulf of Maine) by the Wells National Estuarine Research Reserve (WNERR) started in 2008.  Relationships between mean larval abundance from the shelf collections and larval abundance from estuarine collections were assessed using cross-correlation analyses for three species: Black Sea Bass (Centropristis striata), Windowpane (Scophthalmus aquosus), and Summer Flounder (Paralichthys dentatus).  Patterns from cross-correlation analyses will be used to describe range shifts for the three species.

 

*Weissman, Amelia¹, John Mandelman², Dave Rudders³, and James Sulikowski¹. Stress and discard mortality of Lophius americanus in the scallop dredge fishery.

¹University of New England, Biddeford, ME, ²New England Aquarium, Boston, MA, ³Virginia Institute of Marine Science

Post-release mortality (PRM) studies are considered a primary research priority, particularly for species and fisheries where discard rates are high, and/or for overfished stocks and species of concern. Lophius americanus, the most lucrative finfish in New England, constitutes the second highest bycatch species within the scallop dredge fishery. Despite its commercial importance, no data exists on the mortality rates of monkfish for any gear type. Given these shortcomings, our goals were to evaluate the stress and PRM of monkfish captured in scallop dredge gear. This was accomplished by assessing various physical and physiological conditions. To quantify stress levels, blood samples were taken to measure cortisol, lactate, hemoglobin, and hematocrit concentrations. In addition, a series of reflex responses were tested and injury codes, ranging from 1 (uninjured) to 4 (dead), were assigned to each monkfish in order to develop vitality indices. To correlate the aforementioned parameters to discard mortality, monkfish were held in onboard flow-through seawater tanks and all stress indicators were reassessed after a 72-hour holding period. Preliminary results suggest that number of reflex responses decreased significantly as exposure time (p<0.0001), tow duration (p = 0.007), and air temperature (p = 0.002) increased. In addition, average cortisol levels significantly increased as exposure time (mean change: 2.5 to 12.0 ng/ml; p = 0.003) and tow duration (mean change: 0.9 to 2.4 ng/ml; p = 0.0001) increased.  Analysis of the tank study indicates that 80% of monkfish placed in holding tanks died after 72 hours, regardless of initial vitality index.

 

*Winton, Megan¹, Gavin Fay¹, Heather Haas², Michael Arendt³, Susan Barco⁴, Michael James⁵, Christopher Sasso⁶, and Ronald Smolowitz⁷. Estimating loggerhead sea turtle densities from satellite telemetry data using geostatistical mixed models.

¹Department of Fisheries Oceanography, School for Marine Science and Technology, University of Massachusetts Dartmouth, 200 Mill Road, Suite 325, Fairhaven, MA 02719, ²NOAA Fisheries, Protected Species Branch, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, ³South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC 29412, ⁴Virginia Aquarium and Marine Science Center, 717 General Booth Blvd, Virginia Beach, VA 23451, ⁵Fisheries and Oceans Canada, 531 Brandy Cove Road, St. Andrews, New Brunswick ESB 2L9, ⁶NOAA Fisheries, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, FL, ⁷Coonamessett Farm Foundation, 277 Hatchville Road, East Falmouth, MA 02536

Data collected via satellite telemetry devices are often used to inform spatial conservation measures for threatened sea turtle populations. Most applied telemetry studies aim to reconstruct the continuous utilization distribution underlying reported locations to characterize the relative intensity of space use. However, commonly applied space use estimators do not directly estimate the underlying distribution of interest and, perhaps more importantly, ignore correlations in space and time that may bias estimates. Here we describe how geostatistical mixed models, which explicitly account for spatial and/or temporal correlation using Gaussian random fields, can be applied to directly approximate densities from satellite telemetry data. We illustrate this approach via application to satellite telemetry location observations collected from two hundred and seventy-one large juvenile and adult loggerhead sea turtles in the western North Atlantic from 2004-2016. We demonstrate how such models can be used to predict the overall spatial distribution of tagged individuals, as well as seasonal shifts in densities at smaller time scales. For tagged loggerheads, overall predicted densities were greatest in the shelf waters along the US Atlantic from Florida to North Carolina, but monthly predictions highlight the importance of summer foraging habitat in the mid-Atlantic Bight.