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Environmentally explicit models can improve model performance and our understanding of biological processes. However, these models must be retested over time, as the mechanisms influencing biological processes can change. The relationship between recently settled young‐of‐year (i.e., settlers) and pre‐recruit American lobsters was revisited to determine if our perception on post‐settlement lobster processes has changed. Analyses were focused within the southern region of the species' latitudinal range (Rhode Island, United States), where several environmental factors have been theorized to contribute to the Southern New England stock decline and continued depleted state. The inclusion of additional, recent years' data provided insight on how the density‐dependent nature of the settler–pre‐recruit lobster relationship has varied over time. Including both new and retested environmental drivers reaffirmed the importance of incorporating environmental data when describing this process. Specifically, modeling revealed the importance of epizootic shell disease, finfish predators, and Asian shore crabs in the settler–pre‐recruit relationship. Including disease, predation, and competition metrics in the lobster post‐settlement relationship has allowed for improved modeling and insight into settlement dynamics. This renewed analysis supports reevaluating environmentally explicit models over time and calls for further directed research regarding the biological processes we seek to model with time series data. [ABSTRACT FROM AUTHOR]

There is limited understanding of the mechanisms underlying the marked spatial and temporal trends in landings of American lobster in Canada since the mid-1980s, and little ability to forecast changes. We built an individual-based model for three Lobster Fishing Areas (LFAs) in Canada that uses the annual density of benthic recruits in nursery grounds to generate an index of exploited biomass 6 to 10 years in the future, using von Bertalanffy growth equations complemented with inter-individual variability in growth, and regional maturity ogives and spawning probabilities to allow exclusion of ovigerous females from the exploitable biomass. We found significant positive relationships between the modelled biomass index and fisheries landings in all three LFAs. Out-of-sample validation in two LFAs (longer time series) using 1-year and 6-year reduced data sets revealed mean annual prediction errors of 11.4% and 11.2%, and 23.7% and 51.7%, respectively. Our findings strongly suggest benthic recruitment indices could help make strategic decisions concerning lobster fishing activities, and they argue for the continued and expanded monitoring of lobster benthic recruitment in Canada. [ABSTRACT FROM AUTHOR]

Objective: The commercial importance of Jonah crabs Cancer borealis and Atlantic rock crabs Cancer irroratus has increased over the past few decades, but both species are still data limited. Objectives were to determine the spatial distributions of Jonah and Atlantic rock crabs over time and to estimate associations with environmental variables. Methods: Data were from the Northeast Fisheries Science Center offshore spring bottom trawl surveys during 1968–2021 on Georges Bank and in the Mid‐Atlantic Bight. Environmental preferences for temperature (°C), depth (m), and grain size (ϕ) were estimated using generalized additive models, and the habitat usage between the two crabs were compared using empirical cumulative distribution functions. Result: The spatial distributions of Jonah and Atlantic rock crabs changed over time. Grain size was the most important environmental variable for predicting presence of Jonah crabs, and depth was the most important variable for explaining presence of Atlantic rock crabs. The generalized additive model with the best cross validation and the lowest Akaike information criterion for both crabs included all environmental, spatial, and temporal variables. Conclusion: Jonah and Atlantic rock crabs have different spatial distributions and environmental preferences. Jonah crabs preferred slightly warmer temperatures, deeper depths, and muddier sediments than Atlantic rock crabs. As the commercial importance for Jonah crabs increases, information on their population distribution and habitat usage is important for effective management. Impact StatementJonah crabs and Atlantic rock crabs were traditionally considered bycatch species in the American lobster fishery until the 1990s but have become commercially important since then. While data are still limited for these two species, they occupy different habitats and their spatial distributions shift northward and inshore over time. [ABSTRACT FROM AUTHOR]

News organizations and journalists are important and influential actors in environmental politics. Their reporting on social and environmental issues often follows issue-attention cycles (IACs) that emphasize drama and problematization to maintain public interest. This study examined nearly 13 years of news coverage to understand the media discourse about the Critically Endangered North Atlantic right whale (NARW) and its conservation. Content analysis and critical discourse analysis were used to analyze 356 texts published in six large US newspapers between January 1, 2010 and March 15, 2023. NARW conservation and management received increased public attention and an IAC began in 2017 after an Unusual Mortality Event began, with 75 percent of the sampled articles (n = 267) published from 2017 on. The Boston Globe published a majority of the sampled texts (n = 209) and Globe reporter David Abel was the most prolific journalist with 50 bylines. The coverage featured six themes representing threats to the species, science and technological development, and tourism, local lifestyle, and culture. The most common topic was that of American lobster fishing gear and whale entanglements (n = 162, 45.5%). In that discourse journalists emphasized the political ecology of NARW conservation, focusing on disagreements between whale experts and advocates and commercial lobster fishermen and their allies as they sought to influence decision making by the National Marine Fisheries Service. Journalists presented the issue through a conflict frame and each group used distinct discursive strategies in an attempt to shape the discourse and public opinion related to new or stricter regulations for the commercial lobster fishery designed to reduce the risk of entanglement for NARWs. Findings suggest that this IAC related to NARW science and conservation has already moved through at least three of five key stages and will inevitably lose public interest, which has important implications for future communication and advocacy related to NARW conservation. This case study demonstrates the continued importance of media to conservation - as public forums for discussion, essential parts of organizational strategies for change, and as an externality that can influence conservation outcomes. Support for communication research and practice are vital to successful conservation. [ABSTRACT FROM AUTHOR]

Oceanographic changes are occurring more rapidly in recent decades, with new implications for ocean ecosystems and adjacent human communities. It is important to bring attention to these changes while they are unfolding rather than after they have occurred. Here we report on a rapid shift toward colder, fresher water in the deep Gulf of Maine that, as of mid-June 2024, has persisted for at least six months. The shift likely represents an influx of Labrador Slope Water and resembles conditions that predated a major warming shift that occurred in 2011-2012. Deep-water oceanographic conditions in the Gulf of Maine have a strong influence on ecosystem dynamics, including the prey of critically endangered North Atlantic right whales, the seasonal and disease dynamics of American lobster, and the distribution and abundance of kelp forest communities, among others. Oceanographic surprises have an important role in this system, and monitoring how this shift unfolds, oceanographically and ecologically, will give new insights into how oceanographic signals can inform our understanding of ecosystem responses. [ABSTRACT FROM AUTHOR]

Abstract American lobster inhabit the unique, brackish Bras d’Or Lake system, although densities are low compared to areas with similar habitats in the Atlantic Ocean. Nevertheless, lobsters are an important part of local First Nation (Mi’kmaq) food and culture. We used acoustic telemetry and habitat mapping, combined with local Mi’kmaw knowledge, to document the movements and habitat use of adult lobsters within a section of the Lake. Movement patterns of acoustically tagged individual lobsters were analyzed with both resource selection functions and integrated step selection functions using data obtained from a high-resolution VEMCO Positioning System within a restricted bay in the Bras d’Or Lake. The resource selection function suggested stronger selections of substrates that contained a combination of soft and hard sediments. While the integrated step selection functions found substantial individual variability in habitat selections, there was a trend for lobsters to exhibit more resident behaviour on the combined soft/hard substrates despite the fact these sediments provided little in the way of obvious shelters for the animals. Adult lobsters at this site have very little risk of predation, which presumably allows them to freely exhibit exploratory behaviours and reduce their association with substrates that provide shelters.

In contrast to abiotically formed carbonates, biogenetic carbonates have been observed to be nanocomposite, organo-mineral structures, the basic build-blocks of which are particles of quasi-uniform size (10–100 nm) organized into complex higher-order hierarchical structures, typically with highly controlled crystal-axis alignments. Some of these characteristics serve as criteria for inferring a biological origin and the state of preservation of fossil carbonate materials, and to determine whether the biomineralization process was biologically induced or controlled. Here we show that a calcium storage structure formed by the American lobster, a gastrolith initially consisting of amorphous calcium carbonate (ACC) and amorphous calcium phosphate (ACP), post-mortem can crystallize into (thus secondary) calcite with structural properties strongly influenced by the inherited organic matrix. This secondary calcite meets many structural criteria for biominerals (thus called the biomorphic calcite), but differs in trace element distributions (e.g., P and Mg). Such observations refine the capability to determine whether a fossil carbonates can be attributed to biogenic processes, with implications for the record of life on Earth and other terrestrial planets. [ABSTRACT FROM AUTHOR]

We build on previous research describing correlative links between changes in the abundance of the copepod Calanus finmarchicus , a foundational zooplankton species of the pelagic food web, and diminishing recruitment of young-of-year American lobster (Homarus americanus) to benthic nurseries in the Gulf of Maine. Using parallel 31-year time series of lobster larvae and zooplankton collected on the New Hampshire coast between 1988 and 2018, we investigated how changes in phenology of stage I larval lobster and their putative copepod prey, C. finmarchicus , affect their temporal overlap and potential to interact during the larval season. We found that over the time series both the lobster egg hatch and first appearance of larvae began earlier in the season, a trend significantly correlated with ocean warming. The last appearance of larvae in late summer has been delayed, however, thereby extending the larval season. Even with the longer larval lobster season, the C. finmarchicus season has increasingly been ending before the peak abundance of stage I lobster larvae. The net effect is a widening mismatch in phenology of the two species, an outcome consistent with the hypothesis that changes in abundance and phenology of C. finmarchicus have contributed to recent declines in lobster recruitment. [ABSTRACT FROM AUTHOR]

American lobster inhabit the unique, brackish Bras d'Or Lake system, although densities are low compared to areas with similar habitats in the Atlantic Ocean. Nevertheless, lobsters are an important part of local First Nation (Mi'kmaq) food and culture. We used acoustic telemetry and habitat mapping, combined with local Mi'kmaw knowledge, to document the movements and habitat use of adult lobsters within a section of the Lake. Movement patterns of acoustically tagged individual lobsters were analyzed with both resource selection functions and integrated step selection functions using data obtained from a high-resolution VEMCO Positioning System within a restricted bay in the Bras d'Or Lake. The resource selection function suggested stronger selections of substrates that contained a combination of soft and hard sediments. While the integrated step selection functions found substantial individual variability in habitat selections, there was a trend for lobsters to exhibit more resident behaviour on the combined soft/hard substrates despite the fact these sediments provided little in the way of obvious shelters for the animals. Adult lobsters at this site have very little risk of predation, which presumably allows them to freely exhibit exploratory behaviours and reduce their association with substrates that provide shelters. [ABSTRACT FROM AUTHOR]

Understanding population connectivity helps inform resource and conservation managers about appropriate boundaries for management units. However, for many species facing recent increases in fishing or environmental pressure, accurate information on population structure is lacking. Reef Bugs (Thenus australiensis), commonly known as Moreton Bay Bugs, are iconic shovel-nosed lobsters in northern Australia and an increasingly important fisheries resource. Around 80% of landings occur in the Queensland East Coast Otter Trawl Fishery (ECOTF) where the first stock assessment of the species is underway. However, knowledge about population structure to inform stock assessment is lacking. We used genome complexity reduction-based sequencing to characterise high-quality Single Nucleotide Polymorphisms (SNPs) used to evaluate population structure among three management zones of the ECOTF. Post-filtering, a total of 3,031 SNPs were used to infer no genetic differences among locations indicating strong genetic population connectivity. The presence of a single panmictic population was further supported by cluster and kinship analyses. Broad-scale genetic connectivity likely results from pelagic larval dispersal due to limited adult movements. Findings of high gene flow among connected populations indicate a single biological stock of T. australiensis on Australia's east coast and will inform future fisheries management initiatives. [ABSTRACT FROM AUTHOR]

Greater embryo mass confers an advantage in the face of sub-lethal starvation for larvae of the American lobster, Homarus americanus H. Milne Edwards, 1837. We reared larvae in the laboratory and recorded body size, molt increment, stage duration, and mortality during the three larval instars and postlarval stages. Larvae were either fed continuously or subjected to starvation periods immediately after hatching. Larval mass increased with embryo mass suggesting that energetic advantages of heavier embryos are conferred to the larvae. Stage I larvae hatched from clutches with heavier embryos and had lower mortality after five days without food. Stage I duration decreased with increasing embryo mass in treatments with initial periods without food of three, four, and five days. We also observed greater size increase at first molt and larger postlarval size in some treatments. Our results suggest that larger embryos produce larvae that are more resistant to starvation, which may provide a survival advantage when experiencing variable food supply due to the patchy distribution of their planktonic prey. [ABSTRACT FROM AUTHOR]

The American lobster (Homarus americanus Milne Edwards, 1837) is an ecologically and economically valuable invertebrate in the Northwest Atlantic. Its geographic range is shifting northward due to ocean warming. While extensive research on the thermal tolerance of this species has been performed on adults and postlarvae, there have been few studies focused on its multiple early developmental stages. We applied transcriptomics to investigate transcriptional changes in laboratory-reared American lobster developmental stages I through V. Changes in gene expression were contextualized in the ontogenetic shifts in distribution that these different life history stages experience, with highly active stage IV exhibiting increased cellular metabolism and shell-building processes. We identified differential expression of transcripts related to thermal and UV stress in planktonic stages I-IV compared to benthic stage V, which suggests innate molecular defenses against these stressors. Together, these findings further our understanding of crustacean development in the context of climate change and can be used to inform population distribution modeling efforts. They also provide evidence for the need to investigate the potential trade-offs associated with responding to a changing environment on a stage-by-stage basis. [ABSTRACT FROM AUTHOR]

Host-microbe dynamics are of increasing interest in marine research due to their role in host health and productivity. Changes in the shell microbiome of American lobsters have been associated with epizootic shell disease, a syndrome that is spreading northwards across the eastern U.S. and Canadian Atlantic coast. This study analyzed differences in alpha and beta diversity, as well as differentially abundant taxa, in the shell-associated bacterial community of apparently healthy lobsters from four lobster fishing areas (LFAs) in Atlantic Canada. Over 180 lobsters from New Brunswick, Nova Scotia and Prince Edward Island (PEI) were sampled during seven sampling events over four sampling months. The bacterial community was identified using novel PacBio long-read sequencing, while alpha and beta diversity parameters were analyzed using linear regression models and weighted UniFrac distances. The bacterial richness, diversity and evenness differed by sampling location, sampling month, and molt stage, but not by lobster sex or size, nor sampling depth. Similarly, based on LFA, sampling month, year and lobster molt stage, the shell microbiome differed in microbial community composition with up to 34 out of 162 taxa differing significantly in abundance between sampling groups. This large-scale microbial survey suggests that the shell microbial diversity of apparently healthy lobsters is influenced by spatial and temporal factors such as geographic location, as well as the length of time the carapace is exposed to the surrounding seawater. [ABSTRACT FROM AUTHOR]

Male lobsters (Homarus americanus) harvested as 'quarters' (1.25 lbs/567 g) in two time periods (winter, N = 16, and summer, N = 25) of 2018 are examined. Indicators of quality data were collected for each lobster, including non‐invasive measures (shell hardness, carapace length, sex, live weight, colour, body shape, location, time of harvest) and invasive measures (blood protein [BRIX] level at time of harvest, cooked weight, meat content). Lobster BRIX levels are used as a proxy for actual meat content and as the key indicator of lobster quality. A regression model of the relationship between the natural logarithmic transformation of lobster BRIX levels (independent variable) and meat content yield as a percentage of shell‐on (uncooked) weight (dependent variable) is presented. The objective of this study is to evaluate alternative BRIX‐based decision rules for achieving desired meat content percentage yields for preparing shipments to global markets. The present study found that BRIX‐based grading rules can be determined to achieve minimum desired meat yields, minimum overall shipment yields and minimum proportions of shipments below desirable yield rate. For a minimum desired industry threshold of 24% meat content, the preferred BRIX value rules are (i) 8.5 mg mL−1 and (ii) '9 mg mL−1 with 10% plus condition'. These rules improve the admissibility of samples and reduce the risk of below desirable meat yields. [ABSTRACT FROM AUTHOR]

The American lobster, Homarus americanus , H. Milne Edwards, 1837 is an ecologically, economically, and culturally valuable marine resource for the coastal communities in the Gulf of Maine. Lobsters in the Gulf of Maine are experiencing the effects of rapid warming and acidification due to climate change. Lobster shells are comprised of chitin with precisely precipitated minerals (calcite, amorphous calcium carbonate, and carbonate apatite) that provide structural integrity to the shell and protection against predators and microbial intrusion. We examined the combined effects of ocean warming and acidification on shell mineralogy, epibiont abundance, and growth in early benthic juveniles. Lobsters were grown under six different temperature/pCO2 treatment conditions over 52 days (three replicates per treatment) aligned with environmentally relevant as well as predicted future extremes. Elevated pCO2 and temperature led to a decrease in shell calcium and magnesium content, suggesting that these environmental stressors inhibit shell biomineralization. There was an interactive effect of the stressors on epibiont abundance with the probability of epibiont coverage increasing with increasing pCO2 and temperature. Elevated pCO2 alone was significantly correlated (P = 0.002) to decreased growth, but only for female lobsters. Ocean acidification and warming significantly affect shell integrity in juvenile lobster, increasing risk to injury and disease with potential downstream consequences for the lobster fishery. [ABSTRACT FROM AUTHOR]

News organizations and journalists are important and influential actors in environmental politics. Their reporting on social and environmental issues often follows issue-attention cycles (IACs) that emphasize drama and problematization to maintain public interest. This study examined nearly 13 years of news coverage to understand the media discourse about the Critically Endangered North Atlantic right whale (NARW) and its conservation. Content analysis and critical discourse analysis were used to analyze 356 texts published in six large US newspapers between January 1, 2010 and March 15, 2023. NARW conservation and management received increased public attention and an IAC began in 2017 after an Unusual Mortality Event began, with 75 percent of the sampled articles (n = 267) published from 2017 on. The Boston Globe published a majority of the sampled texts (n = 209) and Globe reporter David Abel was the most prolific journalist with 50 bylines. The coverage featured six themes representing threats to the species, science and technological development, and tourism, local lifestyle, and culture. The most common topic was that of American lobster fishing gear and whale entanglements (n = 162, 45.5%). In that discourse journalists emphasized the political ecology of NARW conservation, focusing on disagreements between whale experts and advocates and commercial lobster fishermen and their allies as they sought to influence decision making by the National Marine Fisheries Service. Journalists presented the issue through a conflict frame and each group used distinct discursive strategies in an attempt to shape the discourse and public opinion related to new or stricter regulations for the commercial lobster fishery designed to reduce the risk of entanglement for NARWs. Findings suggest that this IAC related to NARW science and conservation has already moved through at least three of five key stages and will inevitably lose public interest, which has important implications for future communication and advocacy related to NARW conservation. This case study demonstrates the continued importance of media to conservation – as public forums for discussion, essential parts of organizational strategies for change, and as an externality that can influence conservation outcomes. Support for communication research and practice are vital to successful conservation.

The American lobster fishery is the most economically significant commercial fishery in Atlantic Canada and takes place in waters that are warming due to climate change. Lobster are poikilotherms that tolerate a wide range of seasonal temperatures with an optimal range of 12–18 °C. Lobster in the Canadian Maritimes may be naturally acclimated to a wide range of temperatures and thus, could have a wide range of thermal tolerance that may be distinct across regions. The present study used non-invasive open-source tools to explore differences in thermal tolerance in real time between geographically separated lobster populations from around the Canadian Maritimes. Lobsters were acquired from six lobster fishing areas in the Canadian Maritimes and acclimated to either warm (15 °C) or cold (5 °C) water for two weeks before the onset of thermal trials. Geographic origin was not a significant predictor of estimated thermal maximum, while acclimation temperature was a significant predictor. These results suggest that thermal tolerance is more strongly linked to acclimation temperature than to geographic region.

Invertebrate larvae are often abundant in the surface ocean, which plays a key role in their dispersal and connectivity. Pelagic microhabitats characterized by small‐scale hydrographic variability are complex and ubiquitous in the coastal ocean, but their study is challenging, and they have been largely neglected in meroplankton ecology. Surface convergences, i.e., surface microhabitats featuring convergent horizontal currents, may aggregate the last larval stage of the American lobster and could provide shelter and food for Stage IV postlarvae and thus enhance their condition. We tested these hypotheses by conducting a series of cruises in the southwestern Gulf of Maine in summer 2021, sampling 15 paired sets of potential convergences and off‐convergence unstructured habitat. We measured postlarval abundance, surface hydrography, acoustic backscatter, and circulation. Experiments and image analysis compared condition, color, and morphology of postlarvae sampled inside and outside potential convergences. Potential convergences varied in near‐surface hydrographic patterns, with most displaying consistency among two transects and diverse patterns in salinity and temperature (e.g., across‐convergence gradients with equal or different signs). While the highest postlarval abundances were found in convergences, abundance patterns on and off convergences were not consistent, and another analysis indicated higher abundance in convergences than in a 7‐year untargeted surface ocean data set. Experiments indicated no survivorship differences among convergence and non‐convergence individuals at two temperatures, while image analyses revealed differences in color and size. Physical measurements and qualitative neuston community analyses indicated substantial heterogeneity among potential convergences. Our results reinforce that small‐scale heterogeneities are highly variable but important to the ecology of meroplankton, including the pelagic and neustonic habitats where lobster postlarvae are abundant. [ABSTRACT FROM AUTHOR]

Simple Summary: The clutches of berried female lobsters can be classified into four stages based on appearance: black with tightly packed eggs (stage 1), brown (stage 2) or orange (stage 3) with loosely packed eggs (stage 3), and hatching (stage 4, clutch "mossy"). This scheme has been used for decades, yet precisely how it relates to the biology of the developing eggs has not been investigated. We kept berried females in aquaria and monitored both the appearance of their clutches and investigated eggs closely by picking ten at regular intervals and inspecting them under a microscope. Our findings suggest additional criteria to the staging scheme to increase its accuracy. Firstly, clutches should be inspected closely enough to note whether individual eggs are uniform in colour or two-toned, which indicates how much yolk is present. Secondly, stage 3 clutches should include all eggs that contain ≤1/3 yolk to capture the period of rapid spring-time development leading to hatch. Thirdly, the presence of pre-zoea should be used to indicate a hatching (stage 4) clutch as they do not turn "mossy" (empty egg casings and adhesive substance visible) until late in the hatching process. Pre-zoea are newly hatched embryos not yet moulted to larvae and recognizable by their oval shape. Qualitative visual clutch staging is a useful tool for rapidly and non-invasively assessing the developmental stage of American lobster, Homarus americanus, embryos. While such a scheme has been used in fisheries monitoring strategies in Canada since the 1980s, the biological relevance of its four visually distinguishable stages is poorly understood. We conducted a laboratory experiment in which 10 ovigerous females were housed and the development of their embryos regularly assessed, both qualitatively and quantitatively, from November until hatching in July/August. We confirmed the biological relevance of the qualitative staging scheme by showing clear quantitative differences in the duration and rate of embryonic development of stages 2–4 (stage 1 was not assessed as the precise spawning date was unknown). Stage 2 represents winter–spring "dormancy". Stage 3 represents a shorter period of rapid development preceding hatch. Stage 4 represents hatching. We also recommend some improvements to the qualitative staging scheme, specifically (1) adding criteria related to the portion of eggs that are occupied by yolk to increase the accuracy of staging, (2) slightly redefining stage 3 to ensure it encompasses the full period of rapid embryonic development pre-hatch, and (3) adding the presence of pre-zoeae as a key indicator of hatching to avoid the misclassification of clutches in the early stages of hatching or those that are completely spent but still have adhesive substance. [ABSTRACT FROM AUTHOR]

Size distribution and size frequency information of American lobsters (Homarus americanus) are often used to help estimate the age distributions, and reproductive output for the species and to guide the determination of appropriate minimum legal sizes for the fishery. This study used truncated linear regression models to estimate the effects of sampling year, sampling month, lobster sex and water depth on the lobster size. A dataset of almost 130,000 trap–caught lobsters from the two most important lobster fishing areas of Atlantic Canada collected over a 12-year period (2004–2015) was analyzed. It was shown that truncated models can help to account for biases due to the trap sampling method from vessels and from wharf samplings. There were significant annual and seasonal changes in size distribution, and data collected outside the fishing season showed a significant increase in carapace length in 2014 and 2015, potentially reflecting a northward shift of the range of lobster populations due to more favourable settlement and recruitment habitats. Size also increased in late summer, likely due to moult. Our results demonstrated that landed lobsters, especially females, were smaller than the predicted size-at-maturity in the region (96.5 mm carapace length), which could have long-term repercussions for the stock's reproductive potential. [ABSTRACT FROM AUTHOR]

Occurrence of developmental malformations is of interest since they potentially influence organismal performance and fitness. We report an increased incidence (⁓ 46 fold) of physical malformations in the larvae of the American lobster Homarus Gammarus (Linnaeus, 1758) in response to seawater acidification (–0.58 pH units relative to nominal pH 8.0). We observed three malformations under the influence of seawater acidification previously undescribed in lobster larvae: a flared carapace, twisted tail, and cross claw. Larvae reared under seawater acidification exhibit significantly lower survivorship (by ⁓14%) and the occurrence of a malformation decreases survivorship (12.7%). Larvae with four types of malformations did not progress through development to reach post-larval stages. Namely, these malformations were a flared carapace, curled carapace, twisted tail, and cross claw. Results from this study provide photographic documentation of various lobster larval malformations that ultimately affect individual success and can be applied for quality-control in hatcheries. [ABSTRACT FROM AUTHOR]

The crustacean infraorder Astacidea is represented by two freshwater (Astacoidea and Parastacoidea) and two marine superfamilies (Enoplometopoidea and Nephropoidea). The antennule setation and sternal morphology were examined in specimens of 1) Parastacoidea: Cherax destructor , C. quadricarinatus , and C. tenuimanus from the Australian mainland; Astacopsis franklinii from Tasmania; C. gherardii , C. monticola, C. peknyi , and C. snowden from New Guinea; Paranephrops planifrons from New Zealand; Parastacus brasiliensis from Brazil; P. pugnax from Chile; and Astacoides madagascarensis from Madagascar; 2) Astacoidea: Pacifastacus leniusculus from Japan (where it is non-native); Procambarus clarkii and P. virginalis from the aquarium trade; and Cambaroides dauricus, C. schrenckii , C. similis , and C. wladiwostockiensis from Russia; 3) Enoplometopoidea: Enoplometopus chacei from Japan ; E. debelius and E. occidentalis from the aquarium trade; and 4) Nephropoidea: Homarus americanus from the USA fish market; Metanephrops neptunus from Taiwan; and Metanephrops japonicus , Nephropsis stewari , and Thaumastocheles japonicus from Japan. Antennular setation and sternal morphology were identified as key taxonomic characters to distinguish between the four Astacid superfamilies (Astacoidea, Parastacoidea, Enoplometopoidea, and Nephropoidea). The two new key characters are described and illustrated in detail. [ABSTRACT FROM AUTHOR]

Abstract Male lobsters (Homarus americanus) harvested as ‘quarters’ (1.25 lbs/567 g) in two time periods (winter, N = 16, and summer, N = 25) of 2018 are examined. Indicators of quality data were collected for each lobster, including non‐invasive measures (shell hardness, carapace length, sex, live weight, colour, body shape, location, time of harvest) and invasive measures (blood protein [BRIX] level at time of harvest, cooked weight, meat content). Lobster BRIX levels are used as a proxy for actual meat content and as the key indicator of lobster quality. A regression model of the relationship between the natural logarithmic transformation of lobster BRIX levels (independent variable) and meat content yield as a percentage of shell‐on (uncooked) weight (dependent variable) is presented. The objective of this study is to evaluate alternative BRIX‐based decision rules for achieving desired meat content percentage yields for preparing shipments to global markets. The present study found that BRIX‐based grading rules can be determined to achieve minimum desired meat yields, minimum overall shipment yields and minimum proportions of shipments below desirable yield rate. For a minimum desired industry threshold of 24% meat content, the preferred BRIX value rules are (i) 8.5 mg mL−1 and (ii) ‘9 mg mL−1 with 10% plus condition’. These rules improve the admissibility of samples and reduce the risk of below desirable meat yields.

Host-microbe dynamics are of increasing interest in marine research due to their role in host health and productivity. Changes in the shell microbiome of American lobsters have been associated with epizootic shell disease, a syndrome that is spreading northwards across the eastern U.S. and Canadian Atlantic coast. This study analyzed differences in alpha and beta diversity, as well as differentially abundant taxa, in the shell-associated bacterial community of apparently healthy lobsters from four lobster fishing areas (LFAs) in Atlantic Canada. Over 180 lobsters from New Brunswick, Nova Scotia and Prince Edward Island (PEI) were sampled during seven sampling events over four sampling months. The bacterial community was identified using novel PacBio long-read sequencing, while alpha and beta diversity parameters were analyzed using linear regression models and weighted UniFrac distances. The bacterial richness, diversity and evenness differed by sampling location, sampling month, and molt stage, but not by lobster sex or size, nor sampling depth. Similarly, based on LFA, sampling month, year and lobster molt stage, the shell microbiome differed in microbial community composition with up to 34 out of 162 taxa differing significantly in abundance between sampling groups. This large-scale microbial survey suggests that the shell microbial diversity of apparently healthy lobsters is influenced by spatial and temporal factors such as geographic location, as well as the length of time the carapace is exposed to the surrounding seawater.

The shell microbial community of lobsters--a key factor in the development of epizootic shell disease (ESD)--is still insufficiently researched in Atlantic Canada and many knowledge gaps remain. This study aimed to establish a baseline description and analysis of the shell microbiome of apparently healthy lobsters from four locations in the region. More than 180 lobster shell swab samples were collected from New Brunswick, Nova Scotia and Prince Edward Island (PEI). PacBio long-read 16S rDNA sequencing and bioinformatic analyses in QIIME2 identified the shell-associated bacteria. The shell microbiome of healthy lobsters consisted mainly of the bacterial classes Gammaproteobacteria, Saprospiria, Verrucomicrobiae, Alphaproteobacteria, Flavobacteriia, Acidimicrobiia and Planctomycetia. The microbial composition differed regionally and seasonally, with some classes showing decreased or increased relative abundances in the PEI samples as well as in the winter and spring samples in Nova Scotia. The core shell microbiome included potentially pathogenic as well as beneficial bacterial taxa, of which some were present only in certain regions. Bacterial taxa that have previously been associated with ESD were present on healthy lobsters in Atlantic Canada, but their frequency differed by location, sampling time, and moult stage. This study indicated that geographical and seasonal factors influenced the shell microbiome of apparently healthy lobsters more than host factors such as sex, size, and moult stage. Our results provide valuable reference microbial data from lobsters in a disease-free state. [ABSTRACT FROM AUTHOR]

Sous vide is becoming increasingly popular in the food industry because it results in flavorful, evenly cooked products. This study aimed to better understand the effects of sous vide on physicochemical properties and consumer acceptance of lobster. Shucked lobster tails were sous vide-cooked to internal temperatures of 55, 60, and 65°C for 208, 45, and 10 minutes, respectively, and compared to boiled controls. Samples were evaluated for shear-force, color (L*,a*,b*), salt soluble protein content, moisture content, water holding capacity, weight loss, sarcomere length, and thermal stability. Sous vide-cooked samples were more tender, with greater protein solubility and shorter sarcomere length than the controls. Despite some differences in physicochemical characteristics among the sous vide-cooked samples, hedonic testing confirmed that there were no significant differences in consumer acceptability response to the sous vide cooking parameters. These results help clarify the effects of sous vide cooking on the preparation of consistently high-quality lobster products. [ABSTRACT FROM AUTHOR]

Recent studies have highlighted the significant role of copy number variants (CNVs) in phenotypic diversity, environmental adaptation and species divergence across eukaryotes. The presence of CNVs also has the potential to introduce genotyping biases, which can pose challenges to accurate population and quantitative genetic analyses. However, detecting CNVs in genomes, particularly in non‐model organisms, presents a formidable challenge. To address this issue, we have developed a statistical framework and an accompanying r software package that leverage allelic‐read depth from single nucleotide polymorphism (SNP) data for accurate CNV detection. Our framework capitalises on two key principles. First, it exploits the distribution of allelic‐read depth ratios in heterozygotes for individual SNPs by comparing it against an expected distribution based on binomial sampling. Second, it identifies SNPs exhibiting an apparent excess of heterozygotes under Hardy–Weinberg equilibrium. By employing multiple statistical tests, our method not only enhances sensitivity to sampling effects but also effectively addresses reference biases, resulting in optimised SNP classification. Our framework is compatible with various NGS technologies (e.g. RADseq, Exome‐capture). This versatility enables CNV calling from genomes of diverse complexities. To streamline the analysis process, we have implemented our framework in the user‐friendly r package 'rCNV', which automates the entire workflow seamlessly. We trained our models using simulated data and validated their performance on four datasets derived from different sequencing technologies, including RADseq (Chinook salmon—Oncorhynchus tshawytscha), Rapture (American lobster—Homarus americanus), Exome‐capture (Norway spruce—Picea abies) and WGS (Malaria mosquito—Anopheles gambiae). [ABSTRACT FROM AUTHOR]

Polycyclic aromatic compounds (PACs) present in the water column are considered to be one of the primary contaminant groups contributing to the toxicity of a crude oil spill. Because crude oil is a complex mixture composed of thousands of different compounds, oil spill models rely on quantitative structure–activity relationships like the target lipid model to predict the effects of crude oil exposure on aquatic life. These models rely on input provided by single species toxicity studies, which remain insufficient. Although the toxicity of select PACs has been well studied, there is little data available for many, including transformation products such as oxidized hydrocarbons. In addition, the effect of environmental influencing factors such as temperature on PAC toxicity is a wide data gap. In response to these needs, in the present study, Stage I lobster larvae were exposed to six different understudied PACs (naphthalene, fluorenone, methylnaphthalene, phenanthrene, dibenzothiophene, and fluoranthene) at three different relevant temperatures (10, 15, and 20 °C) all within the biological norms for the species during summer when larval releases occur. Lobster larvae were assessed for immobilization as a sublethal effect and mortality following 3, 6, 12, 24, and 48 h of exposure. Higher temperatures increased the rate at which immobilization and mortality were observed for each of the compounds tested and also altered the predicted critical target lipid body burden, incipient median lethal concentration, and elimination rate. Our results demonstrate that temperature has an important influence on PAC toxicity for this species and provides critical data for oil spill modeling. More studies are needed so oil spill models can be appropriately calibrated and to improve their predictive ability. Environ Toxicol Chem 2023;42:2389–2399. © 2023 SETAC [ABSTRACT FROM AUTHOR]

Crustaceans, which are highly susceptible to the effects of climate change, are critical for food security worldwide. Yet, management rarely evaluates the performance of alternative regulatory strategies under climate‐driven life history change. This limits the development of climate‐ready management plans, undermining fisheries sustainability. We compared the performance of alternative minimum legal size (MLS) regulations under shifts in growth and maturity for American lobster in the Gulf of Maine, the most valuable single‐species commercial fishery in the United States. Across the life history change scenarios examined, increasing MLS improved status indicators, while decreasing MLS eroded status indicators for spawning stock biomass, legal abundance, landings, and exploitation rate. Our results demonstrate that protecting the lobster stock by increasing MLS improves fishery output, highlighting that conservation and industry goals can be complementary. This study exemplifies the utility of MLS as a conservation measure for crustacean fisheries under climate change. [ABSTRACT FROM AUTHOR]

The Marshall Decision of Canada's Supreme Court inspired the Mi'kmaq in the 1700s regarding recognizing fishing rights to the Mi'kmaq communities. Despite this recognition, the Mi'kmaq communities did not have access to commercial fisheries due to the denial of absolute recognition of territories and rights and underrepresentation and participation in resource allocation, governance, and decision-making processes. A potential approach to these issues is the development of third-party Indigenous community-based sustainability certification standards for the American lobster (Homarus americanus) commercial fishery of Nova Scotia by Mi'kmaq communities. An Indigenous certification is a market-based tool that focuses on a holistic approach to the sustainability of the resource, followed by independent accreditations and standards. This study identifies the gaps, challenges, and opportunities of Indigenous-based certifications for the American lobster commercial fishery. We adopt a participatory approach to conventional policy analysis and perform a secondary analysis of existing legal and scientific resources to glean valuable information for supporting the establishment of an Indigenous certification for the American lobster. Certification could provide benefits such as increased control over fisheries management, governance, rights, and socioeconomic interest, building capacity for Mi'kmaq communities, and improving stakeholder relationships. However, there are issues with the entry points of certification for Indigenous peoples related primarily to the dominant actors in accreditation. This study will support further research and engagement of the Mi'kmaq people toward developing an Indigenous certification scheme. [ABSTRACT FROM AUTHOR]

Gulf of Maine waters are warming rapidly, prompting a reevaluation of how commercially important marine species will respond. The goal of this study was to determine the respiratory, cardiac, and locomotory responses of American lobsters (Homarus americanus) to increasing water temperatures and to compare these to similar published studies. First, we measured the heart rate and ventilation rate of 10 lobsters that were confined in a temperature-controlled chamber while exposing them to gradually warming temperatures from 16 to 30 °C over 7 h. Both heart rate and ventilation rate increased along with the temperature up to a break point, with the mean heart rate peaking at 26.5 ± 1.6 °C, while the ventilation rate peaked at 27.4 ± 0.8 °C. In a subset of these trials (n = 5), oxygen consumption was also monitored and peaked at similar temperatures. In a second experiment, both the heart rate and activity of five lobsters were monitored with custom-built dataloggers while they moved freely in a large tank, while the temperature was increased from 18 to 29 °C over 24 h. The heart rate of these lobsters also increased with temperature, but their initial heart rates were lower than we recorded from confined lobsters. Finally, we confirmed that the low heart rates of the freely moving lobsters were due to the methods used by comparing heart rate data from eight lobsters collected using both methods with each individual animal. Thus, while our overall results are consistent with data from previous studies, they also show that the methods used in studies of physiological and behavioral responses to warming temperatures can impact the results obtained. [ABSTRACT FROM AUTHOR]

Objective: There is international pressure to increase the worldwide expanse of marine protected areas (MPAs). However, MPAs often lack preexisting long‐term biological baselines, which are essential for assessing MPA effects and for refining the conservation and socioeconomic benefits they confer to society. Our study addresses this issue by establishing demographic baselines for two commercially important species prior to a proposed fishing ban inside the Northeast Canyons and Seamounts Marine National Monument, a recently established MPA on the continental shelf break approximately 200 km southeast of Cape Cod, Massachusetts. Methods: Samples were obtained by the Commercial Fisheries Research Foundation's American Lobster and Jonah Crab Research Fleet, which is an industry‐based, fishery‐dependent data collection program. Specially trained participants recorded year‐round biological data from their 2013 to 2021 commercial catches of American lobster Homarus americanus and Jonah crab Cancer borealis. Samples were taken from an area inside the MPA and from two areas outside the MPA, spanning 130 km to the east and west. Result: American lobster sizes and sex ratios varied between areas, and their sizes, sex ratios, and proportion of ovigerous females differed between submarine canyons within areas. American lobster sizes, sex ratio, proportion of ovigerous females, and prevalence of shell disease were also affected by season and/or depth. Jonah crab parameters did not vary between areas, but sex ratio varied with season and depth, and the proportion of ovigerous females varied with depth. Conclusion: These demographic baselines are the only data available, at a sufficient spatial and temporal resolution, for evaluating the effects of a proposed fishing ban in the MPA, and they fill important data gaps for stock assessments. To evaluate possible future population changes, it will be necessary to continue collecting data from inside and outside the MPA using comparable methods, and to account for the preexisting sources of variation that we have identified. Impact statementMarine protected areas (MPAs) need monitoring to evaluate their benefits to society. We characterized American lobster and Jonah crab populations inside and outside a newly created MPA while commercial harvest was still operating, thereby providing essential information needed for assessing future responses to planned fishing closures. [ABSTRACT FROM AUTHOR]

Two live specimens of American lobster, Homarus americanus, were observed in very shallow waters, in Caesarea, the central Mediterranean coast of Israel at the end of 2022. This is the first record of this species or any clawed lobster, family Nephropidae, in the warm southeastern Mediterranean. The carapace lengths of the lobsters were 92 and 94 mm, which corresponds with weights of around 600-640 grams, like that of live clawed lobsters imported to Israel from the North-Eastern USA. Although the origin of these lobsters is unknown, it is assumed that they have been released from a restaurant or a cruise ship. They may survive the winter in the Israeli water, but the high temperatures of the sea water during late-spring and summer in the southern Levantine basin will be stressful and lethal for them. [ABSTRACT FROM AUTHOR]

The document titled "Index to Volume 245, December 2023" is an index of articles published in the Biological Bulletin. It includes a range of topics such as the developmental ontology of salps, the embryonic and early larval development of the Pacific razor clam, the use of chromatophores for cryptic coloration in shrimp, the function of BK channels in nematocyst discharge in sea anemones, and the impacts of increasing temperature on the metabolism of American lobsters. The index provides a comprehensive overview of the articles published in the volume and can be a valuable resource for library patrons conducting research on various biological topics. [Extracted from the article]

Abstract Crustaceans, which are highly susceptible to the effects of climate change, are critical for food security worldwide. Yet, management rarely evaluates the performance of alternative regulatory strategies under climate‐driven life history change. This limits the development of climate‐ready management plans, undermining fisheries sustainability. We compared the performance of alternative minimum legal size (MLS) regulations under shifts in growth and maturity for American lobster in the Gulf of Maine, the most valuable single‐species commercial fishery in the United States. Across the life history change scenarios examined, increasing MLS improved status indicators, while decreasing MLS eroded status indicators for spawning stock biomass, legal abundance, landings, and exploitation rate. Our results demonstrate that protecting the lobster stock by increasing MLS improves fishery output, highlighting that conservation and industry goals can be complementary. This study exemplifies the utility of MLS as a conservation measure for crustacean fisheries under climate change.

Climate change is expected to have a significant impact on American lobsters, as they are sensitive to water temperature and may need to relocate to avoid water that is too warm or too cold. This could disrupt their life cycle and potentially lead to a decline in their numbers. The warming of the oceans is already causing issues for lobster populations in warmer areas, where diseases spread more easily. Changes in water temperature could also affect the timing and location of hatching for female lobsters, potentially reducing the number of offspring. This is concerning because the American lobster fishery is the most valuable single species fishery in the United States and is important for the social and economic stability of many coastal communities. Research conducted by Goldstein, a specialist in studying the impact of climate change on crab and lobster fisheries, examines how climate change affects the reproduction, physiology, and movement patterns of these marine species. This research is valuable for understanding the potential consequences of climate change on these important fisheries and can provide insights into how to manage and protect these species in the face of environmental changes. [Extracted from the article]

The American lobster (Homarus americanus) is the most valuable seafood on Canada's Atlantic coast, generating over CAD 800 million in export revenue alone for New Brunswick. However, labor shortages plague the lobster industry, and lobsters must be processed quickly to maintain food safety and quality assurance standards. This paper proposes a lobster estimation orientation approach using a convolutional neural network model, with the aim of guiding the FANUC LR Mate 200 iD robotic arm for lobster manipulation. To validate this technique, four state-of-the-art object detection algorithms were evaluated on an American lobster images dataset: YOLOv7, YOLOv7-tiny, YOLOV4, and YOLOv3. In comparison to other versions, YOLOv7 demonstrated a superior performance with an F1-score of 95.2%, a mean average precision (mAP) of 95.3%, a recall rate of 95.1%, and 111 frames per second (fps). Object detection models were deployed on the NVIDIA Jetson Xavier NX, with YOLOv7-tiny achieving the highest fps rate of 25.6 on this platform. Due to its outstanding performance, YOLOv7 was selected for developing lobster orientation estimation. This approach has the potential to improve efficiency in lobster processing and address the challenges faced by the industry, including labor shortages and compliance with food safety and quality standards. [ABSTRACT FROM AUTHOR]

Simple nutritional condition indicators are needed to provide information on the influence of ecosystem changes on the populations of the American lobster Homarus americanus (H. Milne Edwards, 1837) on various timescales. This study validates the use of the water content (% wet mass) of the digestive gland as an indicator of nutritional condition in the lobster (carapace length 65–127 mm) by assessing its capacity to estimate digestive-gland lipid reserves under variable environmental and physiological conditions. The validation was completed using samples from wild lobsters dissected shortly after being captured during different seasons and in various locations in the St. Lawrence Estuary and Gulf of St. Lawrence (GSL), and data from an environmentally realistic laboratory study on post-ovigerous females from the southern and the northern GSL sampled at different stages of their molt cycle. In both wild and experimental lobsters, water content was the best predictor of lipid reserves compared to other condition indicators (i.e. condition factor, various digestive-gland indices, and hemolymph Brix index). A strong linear relationship was found between lipid and water contents. Lipid content and interrelated molting status were identified as two important factors leading to the variations in water-fat regression equations among groups of wild or experimental lobsters. As lipid content could vary spatiotemporally in unexpected ways in a changing environment, it is recommended to use a sampling event-specific regression line to estimate digestive-gland lipid content from measured water content in field monitoring programs. Combining water content with molt status indicators such as Brix index is recommended to support interpretation of the observed variations in condition. [ABSTRACT FROM AUTHOR]

The impact of the southern Gulf of St. Lawrence American lobster (Homarus americanus) fishery on species bycatch is currently unknown. The composition of the incidental catch, both nonharvestable lobster (by fisheries regulations) and nonlobster species, was systematically collected over the 2015 spring and summer fishing seasons. A total of 51 948 (7147 were nonlobster taxa) individual organisms weighing 13 987.60 kg (1223.91 kg of nonlobster taxa) were captured as bycatch during 73 fishing trips. By weight per trip, the most common lobster bycatch were undersized male and females, and the highest nonlobster species catch were Atlantic rock crab (Cancer irroratus). A semiquantitative assessment of injury and vitality was applied to bycatch as a proxy for discard mortality. The majority of the individuals assessed for visible injury were deemed uninjured (98% both fish and invertebrates); however, postrelease mortality was not measured. A smaller study in 2019 corroborated the 2015 catches and supported current assumptions that the passive gear type, the low diversity of bycatch, and the rapid hand-sorting of the trap minimize the impact of the lobster fishery on incidentally captured taxa. Further scientific monitoring is recommended to better account for all sources of mortality in stock assessments and rebuilding plans.

Coastal and estuarine ecosystems are environments heavily influenced by natural and anthropogenic activities. Chemicals used for pest control in agriculture and aquaculture may accumulate in natural coastal environments. Pyrethroids are common pesticides that are used on crops as well as applied to aquaculture pens and then may disperse in the surrounding ocean once treatment is complete. This study observed the sublethal effects of two pyrethroids, permethrin and deltamethrin (within commercially available formulations), on post-larval stage IV American lobster (Homarus americanus) using growth parameters and metabolic rate as indicators. Observed effects on growth parameters were a decrease in size increment and specific growth rate as well as an increase in intermolt period in stage IV lobsters exposed to 100 μg/kg permethrin. No significant differences were found for intermolt period, size increment, or specific growth rate in deltamethrin-exposed stage IV lobsters. Metabolic rates were not significantly different between deltamethrin-exposed and control lobsters, however, this sublethal effect warrants further investigation. Collectively, these results represent the first examination of the sublethal effects of exposure to pyrethroids formulations in post-larval lobsters, highlighting the potential for effects on non-target marine organisms. [ABSTRACT FROM AUTHOR]

Federal lobster fishing area (LFA) boundaries are part of the infrastructure controlling the temporal and spatial scale of lobster fishing in Atlantic Canada. Changes in the materiality of fishing and accompanying challenges to normative orders affecting access rules have together destabilized the spatial boundaries of LFAs. Changes in lobster distribution, gear innovations to fish in deeper waters, legal maneuverings over licensing, and competition with aquaculture for marine space all challenge LFA boundaries, which changes the distribution of fishing industry benefits and disrupts long-standing local values. Federal managers of the fishery struggle to deal with new assemblages of technology and law and how they interact with marine space. Examining the technology/legal pluralism nexus and their relationship with administrative lines in the water exposes how both affect more-than-human-spatial assemblages. [ABSTRACT FROM AUTHOR]

Epizootic Shell Disease (ESD) has posed a great threat, both ecologically and economically, to the American lobster population of Long Island Sound since its emergence in the late 1990s. Because of the polymicrobial nature of carapace infections, causative agents for ESD remain unclear. In this study, we aimed to identify carapace microbiota associated with ESD and its potential impact on the microbiota of internal organs (green gland, hepatopancreas, intestine, and testis) using high-throughput 16S rRNA gene sequencing. We found that lobsters with ESD harbored specific carapace microbiota characterized by high abundance of Aquimarina, which was significantly different from healthy lobsters. PICRUSt analysis showed that metabolic pathways such as amino acid metabolism were enriched in the carapace microbiota of lobsters with ESD. Aquimarina, Halocynthiibacter, and Tenacibaculum were identified as core carapace bacteria associated with ESD. Particularly, Aquimarina and Halocynthiibacter were detected in the green gland, hepatopancreas, and testis of lobsters with ESD, but were absent from all internal organs tested in healthy lobsters. Hierarchical clustering analysis revealed that the carapace microbiota of lobsters with ESD was closely related to the green gland microbiota, whereas the carapace microbiota of healthy lobsters was more similar to the testis microbiota. Taken together, our findings suggest that ESD is associated with alterations in the structure and function of carapace microbiota, which may facilitate the invasion of bacteria into the green gland. [ABSTRACT FROM AUTHOR]

Maine's coastal communities critically depend on the American lobster fishery, which is now exposed to ocean warming. There is uncertainty about the future robustness of the stock and the economic performance of the fleet appears vulnerable. This research characterizes economic heterogeneity in Maine's fishing fleet using latent class stochastic profit frontier analysis. We explore the diversity of business models and examine how they are associated with the economic performance of the fleet in the prewarming period. The study uses unique firm-level data that capture the operational and economic information of the harvesters in the year 2010, the year before the reported environmental change in the Gulf of Maine. Our findings indicate that economic efficiencies differ based on their choice of business models and it was found that technical upgrades generally contribute to improved economic performance in the prewarming period. Reported societal benefits associated with employment levels have characterized the lobster production environment over firm-level efficiency. This research establishes a critically important baseline for future comparison and quantification of policy reforms within the US lobster fishery. [ABSTRACT FROM AUTHOR]

Perceptions of past ecological change affect views of current ecosystem state, but how do baselines help to shape stakeholders' visions of an idealized future?Here, we investigate links between perceptions of natural baselines and visions for the nearshore Gulf of Maine among a key stakeholder group, active lobster fishers. We ask three related questions: (1) What do fishers perceive as a 'natural' Gulf of Maine? (2) How do perceptions of the past predict individual and collective visions of an ideal future? and (3) How is existing management perceived as supporting these visions?We found that fishers perceived the ecosystem to be 'natural' an average of one decade before they started fishing. Three species dominated views of natural systems: cod Gadus morhua, lobster Homarus americanus, and herring Clupea harengus, but while long‐time fishers associated abundant cod with a natural nearshore Gulf of Maine, memories of a historically cod‐rich Gulf of Maine were fading among some younger fishers who began their careers after the cod crash in the 1990s. Perceptions of 'natural' ecosystems dictated future visions for the majority of taxa; on average, fishers remembered and desired abundant cod and herring, but perceived halibut Hippoglossus hippoglossus and endangered right whales Eubalaena glacialis to have always been rare.Fishers described a vision for the future based on views of past ecological and social baselines, including fisheries deconsolidation and diversification, but expressed a lack of shared vision with and trust in federal management institutions to achieve these goals. In particular, memories of cod abundance in the 1970s and 1980s were coupled with memories of a diversified and accessible fishery, but fishers doubted that the recovery of cod would result in their restored access to cod fisheries.Together our results demonstrate that past personal experiences limit perceptions of what is possible, highlighting both the value and limitations of local ecological knowledge in places that have experienced ecological change over centuries. They also demonstrate how stakeholder perceptions of both social and ecological baselines shape visions for future ecosystems but are mediated by contemporary issues like trust in institutions and fisheries access. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Changes in ambient temperature affect all biological processes. However, these effects are process specific and often vary non-linearly. It is thus a non-trivial problem for neuronal circuits to maintain coordinated, functional output across a range of temperatures. The cardiac nervous systems in two species of decapod crustaceans, Homarus americanus and Cancer borealis, can maintain function across a wide but physiologically relevant temperature range. However, the processes that underlie temperature resilience in neuronal circuits and muscle systems are not fully understood. Here, we demonstrate that the non-isolated cardiac nervous system (i.e., the whole heart: neurons, effector organs, intrinsic feedback systems) in the American lobster, H. americanus, is more sensitive to warm temperatures than the isolated cardiac ganglion (CG) that controls the heartbeat. This was surprising as modulatory processes known to stabilize the output from the CG are absent when the ganglion is isolated. One source of inhibitory feedback in the intact cardiac neuromuscular system is nitric oxide (NO), which is released in response to heart contractions. We hypothesized that the greater temperature tolerance observed in the isolated CG is due to the absence of NO feedback. Here, we demonstrate that applying an NO donor to the isolated CG reduces its temperature tolerance. Similarly, we show that the NO synthase inhibitor L-nitroarginine (LNA) increases the temperature tolerance of the non-isolated nervous system. This is sufficient to explain differences in temperature tolerance between the isolated CG and the whole heart. However, in an intact lobster, the heart and CG are modulated by an array of endogenous peptides and hormones, many of which are positive regulators of the heartbeat. Many studies have demonstrated that excitatory modulators increase temperature resilience. However, this neuromuscular system is regulated by both excitatory and inhibitory peptide modulators. Perfusing SGRNFLRFamide, a FLRFamide-like peptide, through the heart increases the non-isolated nervous system's tolerance to high temperatures. In contrast, perfusing myosuppressin, a peptide that negatively regulates the heartbeat frequency, decreases the temperature tolerance. Our data suggest that, in this nervous system, positive regulators of neural output increase temperature tolerance of the neuromuscular system, while modulators that decrease neural output decrease temperature tolerance. [ABSTRACT FROM AUTHOR]

During the 1990s, coastal habitat off southeastern Massachusetts (SEMA) supported commercially viable fisheries for American lobster (Homarus americanus). Over the past two decades, landings and post‐larval settlement of lobsters in this region, which is near the southern edge of the species' range, have declined substantially, concurrent with a period of significant warming of the coastal waters off southern New England. Previous work has suggested that rising ocean temperatures may adversely impact the survival of larval and early benthic phase (EBP) lobsters and may cause adult lobsters to seek cooler offshore waters during the critical time of larval release. To investigate the manner in which the observed decline in lobster abundance may be linked to warming coastal waters, a high‐resolution hydrodynamic model was used to quantify the increase in water temperature experienced by EBP lobster off SEMA and to supply input to an individual‐based model of lobster larval transport from release areas delineated using fishery‐dependent data of late‐stage egg‐bearing lobsters. The results indicate that rising coastal water temperatures may have adversely impacted EBP lobster recruitment off SEMA by (1) causing an offshore shift in the area of larval release that resulted in a reduction in the delivery of larvae to suitable nearshore EBP habitat and (2) dramatically increasing thermal stress experienced by recently settled EBP lobsters. These findings highlight the implications of warming coastal waters on southern New England lobster population connectivity and provide insight to an understudied mechanism by which climate change affects marine species recruitment. [ABSTRACT FROM AUTHOR]