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1. Potential Repercussions of Offshore Wind Energy Development in the Northeast United States for the Atlantic Surfclam Survey and Population Assessment

   https://doi.org/10.1002/mcf2.10228  

   Borsetti, Sarah ; Munroe, Daphne M. ; Scheld, Andrew M. ; Powell, Eric N. ; Klinck, John M. ; Hofmann, Eileen E. ( February 2023 , Marine and Coastal Fisheries)

   The Atlantic surfclamSpisula solidissimafishery, which spans the U.S. Northeast continental shelf, is among the most exposed to offshore wind energy development impacts because of the overlap of fishing grounds with wind energy lease areas, the hydraulic dredges used by the fishing vessels, and the location of vessel home ports relative to the fishing grounds. The Atlantic surfclam federal assessment survey is conducted using a commercial fishing vessel in locations that overlap with the offshore wind energy development. Once wind energy turbines, cables, and scour protection are installed, survey operations within wind energy lease areas may be curtailed or eliminated due to limits on vessel access, safety requirements, and assessment survey protocols. The impact of excluding the federal assessment survey from wind energy lease areas was investigated using a spatially explicit, agent‐based modeling framework that integrates Atlantic surfclam stock biology, fishery captain and fleet behavior, and federal assessment survey and management decisions. Simulations were designed to compare assessment estimates of spawning stock biomass (SSB) and fishing mortality (F) for scenarios that excluded the survey from (1) wind energy lease areas or (2) wind energy lease areas and potential wind energy lease areas (“call areas”). For the most restricted scenario, the simulated stock assessment estimated 17% lower SSB relative to an unrestricted survey, placing it below the SSB target. The simulatedFincreased by 7% but was still less than the acceptedFthreshold. Changes in biological reference points were driven by the inability to access the Atlantic surfclam biomass within the wind energy lease areas. Deviations in reference points reflected the proportion of the population excluded from the survey. Excluding the Atlantic surfclam assessment surveys from the regions designated for offshore wind development can alter long‐term stock assessments by increasing uncertainty in metrics that are used to set fishing quotas.

    

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2. The Atlantic surfclam fishery and offshore wind energy development: 1. Model development and verification

   Munroe, D.M. ; E.N. Powell ; J.M. Klinck ; A.M. Scheld ; S. Borsetti ; J. Beckensteiner ; E.E. Hofmann ( January 2022 , ICES journal of marine science)

   Competing pressures imposed by climate-related warming and offshore development have created a need for quantitative approaches that anticipate fisheries responses to these challenges. This study used a spatially explicit, ecological-economic agent-based model integrating dynamics associated with Atlantic surfclam stock biology, decision-making behavior of fishing vessel captains, and fishing fleet behavior to simulate stock biomass, and fishing vessel catch, effort and landings. Simulations were implemented using contemporary Atlantic surfclam stock distributions and characteristics of the surfclam fishing fleet. Simulated distribution of fishable surfclam biomass was determined by a spatially varying mortality rate, fishing by the fleet was controlled by captain decisions based on previous knowledge, information sharing, and the ability to search and find fishing grounds. Quantitative and qualitative evaluation of simulation results showed that this modeling approach sufficiently represents Atlantic surfclam fishery dynamics. A fishing simulation showed that the captain's decision-making and stock knowledge, and the distribution of fishing grounds relative to home ports controlled the landed catch. The approach used herein serves as the basis for future studies examining response of the Atlantic surfclam fishery to a nexus of simultaneous, complex natural and anthropogenic pressures, and provides a framework for similar models for other resources facing similar pressures. 

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3. The Atlantic surfclam fishery and offshore wind energy development: 2. Assessing economic impacts

   Scheld, A.M. ; J. Beckensteiner ; D.M. Munroe ; E.N. Powell ; S. Borsetti ; E.E. Hofmann ; J.M. Klinck ( January 2022 , ICES journal of marine science)

   The Atlantic surfclam (Spisula solidissima) fishery generates approximately USD 30 million in landings revenues annually, distributed across ports throughout the US Mid-Atlantic and Northeast. Overlap between areas of Atlantic surfclam harvests and offshore wind energy leasing make the fishery vulnerable to exclusion and effort displacement as development expands in the region. An existing integrated bioeconomic agent-based model, including spatial dynamics in Atlantic surfclam stock biology, heterogeneous captain behaviour, and federal management processes, was extended to incorporate costs and revenues for fishing vessels and processors and used to evaluate the potential economic effects of offshore wind development on the Atlantic surfclam fishery. Fishing activity and economic outcomes were simulated under different offshore wind energy development scenarios that impose spatial restrictions on Atlantic surfclam vessel fishing and transiting behaviour. Decreases in the number of trips and shifts in the spatial distribution of fishing effort reduced revenues for Atlantic surfclam fishing vessels and processors by ∼3–15% and increased average fishing costs by < 1–5%, with impacts varying across development scenarios and fishing ports. The modelling approach used in this analysis has potential for addressing additional questions surrounding sustainable ocean multi-use and further quantifying interactions between offshore wind energy development and commercial fisheries. 

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4. Genetics, Age Demographics, and Shell Size of Atlantic Surfclams from the Southern Edge of Their Range

   https://doi.org/10.1007/s12237-023-01281-z  

   Wisner, Brynne ; Wang, Zhenwei ; Sheehan, Ailey ; Guo, Ximing ; Munroe, Daphne ( October 2023 , Estuaries and Coasts)

   The Atlantic surfclam (Spisula solidissima solidissima) is an economically valuable clam species that supports a major US fishery. Until recently, fishery efforts along the southern edge of the surfclam range were low due to clam mortalities there in the 1990s. Recent surfclam fishing efforts off Virginia raised questions of whether the surfclam population has returned in the southern region or if a single cohort is supporting the fishery there. Questions have also arisen about whetherS. s. similisis among the population fished off the coast of VA.Spisula solidissima similisis a warm-water cryptic subspecies of the Atlantic surfclam. Although morphologically indistinguishable,S. s. similisgrows to a smaller size and is genetically distinct. Atlantic surfclams (n = 103) were collected from the fishing grounds off the coast of VA. Each surfclam was aged, and shell length and tissue weight recorded for comparison to surfclams of the same age from the center of the population. Analyses of mitochondrial (mtCOI) sequences suggests that the two groups sampled off VA are genetically homogeneous, both groups contain two divergent mitochondrial lineages, and one surfclam sampled shares theS. s. similismtCOI sequence. There are multiple cohorts of surfclams, suggesting that environmental conditions may have improved for surfclams in the south, or that this population has acclimated to altered conditions. Further research should investigate the potential for subspecies hybridization.

    

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5. Global hotspots of coherent marine fishery catches

   https://doi.org/10.1002/eap.2321  

   Ong, Joyce J. L. ; Walter, Jonathan A. ; Jensen, Olaf P. ; Pinsky, Malin L. ( April 2021 , Ecological Applications)

   Although different fisheries can be tightly linked to each other by human and ecosystem processes, they are often managed independently. Synchronous fluctuations among fish populations or fishery catches can destabilize ecosystems and economies, respectively, but the degree of synchrony around the world remains unclear. We analyzed 1,092 marine fisheries catch time series over 60 yr to test for the presence of coherence, a form of synchrony that allows for phase‐lagged relationships. We found that nearly every fishery was coherent with at least one other fishery catch time series globally and that coherence was strongest in the northeast Atlantic, western central Pacific, and eastern Indian Ocean. Analysis of fish biomass and fishing mortality time series from these hotspots revealed that coherence in biomass or fishing mortality were both possible, though biomass coherence was more common. Most of these relationships were synchronous with no time lags, and across catches in all regions, synchrony was a better predictor of regional catch portfolio effects than catch diversity. Regions with higher synchrony had lower stability in aggregate fishery catches, which can have negative consequences for food security and economic wealth.

    

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