Modelling ocean acidification effects with life stage-specific responses alters spatiotemporal patterns of catch and revenues of American lobster, Homarus americanus.

Ocean acidification (OA) affects marine organisms through various physiological and biological processes, yet our understanding of how these translate to large-scale population effects remains limited. Here, we integrated laboratory-based experimental results on the life history and physiological responses to OA of the American lobster, Homarus americanus, into a dynamic bioclimatic envelope model to project future climate change effects on species distribution, abundance, and fisheries catch potential. Ocean acidification effects on juvenile stages had the largest stage-specific impacts on the population, while cumulative effects across life stages significantly exerted the greatest impacts, albeit quite minimal. Reducing fishing pressure leads to overall increases in population abundance while setting minimum size limits also results in more higher-priced market-sized lobsters (> 1 lb), and could help mitigate the negative impacts of OA and concurrent stressors (warming, deoxygenation). However, the magnitude of increased effects of climate change overweighs any moderate population gains made by changes in fishing pressure and size limits, reinforcing that reducing greenhouse gas emissions is most pressing and that climate-adaptive fisheries management is necessary as a secondary role to ensure population resiliency. We suggest possible strategies to mitigate impacts by preserving important population demographics.

Condición nutricional de la langosta, Panulirus argus (Decapoda: Palinuridae): 60 años de índices extensivos y variación espacio-temporal en Cuba / Nutritional condition of the lobster, Panulirus argus (Decapoda: Palinuridae): 60 years of extensive indices and spatio-temporal variation in Cuba

Resumen Introducción: En el hábitat natural, el estado nutricional insatisfactorio de un número elevado de ejemplares es expresión de la influencia de factores desfavorables. Objetivo: Determinar variaciones espacio-temporales en el estado nutricional de langostas Panulirus argus, relacionarlas con variaciones reportadas en la comunidad bentónica y demostrar, mediante la aplicación de indicadores analíticos y morfométricos, que la variación de factores ambientales afecta a ambos grupos de índices; y que no todos los índices de condición nutricional evidencian por igual el impacto generalizado del proceso de deterioro ambiental en este golfo. Métodos: Las langostas se capturaron en seis áreas de pesca. La condición nutricional se estimó mediante tres índices no destructivos, poco costosos y de fácil y rápida aplicación (extensivos): índice de refracción de la hemolinfa (IRH), relación peso total / largo total = Klt, y factor de condición (FCA). Las variaciones a largo plazo (60 años) se determinaron mediante índices morfométricos (Klt y FCA). Se analizaron datos de los períodos 1963-1964 (N = 29 001), 1983-1993 (N = 3 123) y 2011-2017 (N = 3 600), separándolos en épocas de Lluvia y Seca. Resultados: En todos los períodos la condición nutricional varió significativamente entre áreas, pero sin similitudes entre períodos. Esto indica que los factores que impactan en el estado nutricional tienen una influencia estocástica más característica de factores ambientales. Aunque los tres índices fueron menores en 2017, sólo IRH disminuyó gradualmente entre 2011 y 2017, lo que sugiere que este índice, y los morfométricos, expresan diferente información. Todas las correlaciones fueron estadísticamente significativas, los coeficientes más altos se establecieron entre los índices morfométricos. El peso total y el Klt no mostraron diferencias entre Seca y Lluvia. Sin embargo, IRH y FCA resultaron mayores en Seca, hecho que se constató para cada sexo. FCA y Klt no presentaron diferencias entre el período 1963-1964 y el período 1983-1993, pero aumentaron (P < 0.05) en el período 2011-2017, lo que, dado el carácter morfométrico de estos índices, se atribuye a la presencia de langostas de mayor peso en las áreas de pesca. Conclusiones: Los menores valores en 2017 y la tendencia gradual al decrecimiento de IRH, corroboran el carácter generalizado del deterioro ambiental en el golfo de Batabanó, lo cual no fue igualmente expresado por los tres índices.

Abstract Introduction: Nutritional condition indices are morphophysiological estimators that quantify the nutritional status of organisms. In the natural habitat, unsatisfactory nutritional stage of numerous individuals is an expression of unfavorable factors. Objectives: Determine spatio-temporal variations in the nutritional condition of lobsters Panulirus argus, relate them to variations reported in the benthic community, and to demonstrate, through the application of analytical and morphometric indices, that variations of environmental factors affects both groups of indices due to its potential magnitude and its generalized nature. Methods: Lobsters were captured at six sites. Nutritional condition was estimated by three non-destructive, inexpensive and quick indices also easy to apply, which it means extensive indices: blood refractive index (BRI), relationship between total weight and total length (K), and condition factor (CFA). Because there are no historical records of BRI, long-term variations (60 years) were determined using morphometric indices (Klt and CFA). Data from the periods 1963-1964 (N = 29 001), 1983-1993 (N = 3 123) and 2011-2017 (N = 3 600) were analyzed, separating them in the rainy and dry seasons. Results: In all the periods the nutritional condition varied significantly between sites, but without similarities between periods. Despite this, it increased progressively in three sites. This indicates that factors impacting nutritional condition have a stochastic influence that is constantly changing, which is more characteristic of environmental factors than anthropogenic factors. Although the three indices showed a lower nutritional condition in 2017, only BRI gradually decreased between 2011 (16.6) and 2017 (14.2), which suggests that this index, and the morphometrics (Klt and CFA), express different information. All correlations were statistically significant but greatest coefficients were established between morphometric indices. The total weight and the Klt index did not show differences between rainy and dry seasons. However, BRI and CFA were statistically greater in dry season, a fact that was found for each sex. Both CFA and Klt decreased slightly (P > 0.05) between the first (1963-1964) and the second (1983-1993) period and then increased (P < 0.05) in the current period (2011-2017). Because they both are morphometric indices, this was attributed to the presence of greater weight lobsters. Conclusions: The lowest values in 2017 and gradually decreasing trend in BRI, corroborate the generalized nature of the environmental deterioration in the Gulf of Batabanó, but this was not equally expressed by the three indices.

Effects of short-term and continuous exposure to reduced salinities on the biochemical composition of larval lobster, Homarus gammarus.

In coastal areas with estuarine influence, exposure to hypo-osmotic conditions may affect larval survival, development and growth. Most knowledge about effects of reduced salinity on coastal organisms is based on keeping individuals under constant conditions in the laboratory. By contrast, little is known about the effects of more realistic situations where organisms are exposed to low salinity over short time scales. Such environmental short-term fluctuations are expected to increase due to climate change. Here, we experimentally evaluated the sublethal effects of both short-term and continuous exposure to moderately reduced salinities (salinity 20 and 25; compared to seawater, salinity 32) in larvae of European lobster Homarus gammarus. Total body dry mass and biochemical composition (measured as: protein and lipid contents) were measured as response variables in Mysis stages I to III. Short-term effects of low salinity were quantified in a group of larvae kept in seawater from hatching until the time of transfer to the test salinities. After ca. 40 % of each moult cycle in seawater (determined in preliminary experiments for Mysis I, II and III), larvae were assigned to a seawater control or reduced salinities lasting for 16 h (i.e. until ca. 50 % of the time spent within the moulting cycle). Effects of continuous exposure to low salinity were quantified when larvae were exposed to the different salinities from hatching, until they reached ca. 50 % of the successive moulting stage. Surprisingly, in the Mysis II and III stages, short-term exposure to low salinity had much stronger effects on accumulation of reserves than the continuous exposure. Such effects were manifested mostly as limited accumulation, or even losses, in the lipid content as compared to reductions in the amount of protein accumulated. The most sensitive stage to exposure to low salinity was the Mysis III; by contrast in Mysis I such effects were relative weak (not always significant). Chronic exposure to low salinity also led to an increase in developmental time especially at the advanced stages. Our results highlight the importance of quantifying effects of environmental fluctuations at different time scales in order to better understand how organisms cope with realistic environmental change in the coastal zones. For H. gammarus, our results suggest that larvae respond adaptively to low salinity by maintaining protein levels at expenses of reductions in lipid accumulation and by extending the developmental time, but the capacity to elicit a fully compensatory response varies ontogenetically.

Expected ocean warming conditions significantly alter the transcriptome of developing postlarval American lobsters (Homarus americanus): Implications for energetic trade-offs.

The American lobster (Homarus americanus) is one of the most iconic and economically valuable fishery species in the Northwestern Atlantic. Surface ocean temperatures are rapidly increasing across much of the species' range, raising concern about resiliency in the face of environmental change. Warmer temperatures accelerate rates of larval development and enhance survival to the postlarval stage, but the potential costs at the molecular level have rarely been addressed. We explored how exposure to current summer temperatures (16 °C) or temperature regimes mimicking projected moderate or extreme warming scenarios (18 °C and 22 °C, respectively) for the Gulf of Maine during development influences the postlarval lobster transcriptome. After de novo assembling the transcriptome, we identified 2542 differentially expressed (DE; adjusted p < 0.05) transcripts in postlarvae exposed to 16 °C vs. 22 °C, and 422 DE transcripts in postlarvae reared at 16 °C vs. 18 °C. Lobsters reared at 16 °C significantly over-expressed transcripts related to cuticle formation and the immune response up to 14.4- and 8.5-fold respectively, relative to those reared at both 18 °C and 22 °C. In contrast, the expression of transcripts affiliated with metabolism increased up to 7.1-fold as treatment temperature increased. These results suggest that lobsters exposed to projected warming scenarios during development experience a shift in the transcriptome that reflects a potential trade-off between maintaining immune defenses and sustaining increased physiological rates under a warming environment. This could have major implications for post-settlement survival through increased risk of mortality due to disease and/or starvation if energetic demands cannot be met.

A new polychelidan lobster preserved with its eggs in a 165 Ma nodule.

Crustacean eggs are rare in the fossil record. Here we report the exquisite preservation of a fossil polychelidan embedded within an unbroken nodule from the Middle Jurassic La Voulte-sur-Rhône Lagerstätte (France) and found with hundreds of eggs attached to the pleon. This specimen belongs to a new species, Palaeopolycheles nantosueltae sp. nov. and offers unique clues to discuss the evolution of brooding behaviour in polychelidan lobsters. In contrast to their development, which now relies on a long-lived planktic larval stage that probably did not exist in the early evolutionary steps of the group, the brood size of polychelidan lobsters seems to have remained unchanged and comparatively small since the Jurassic. This finding is at odds with reproductive strategies in other lobster groups, in which a long-lived planktic larval stage is associated with a large brood size.

Injuries and Exposure to Time Lobstering in Northeast US Inshore Lobster Fleet.

Objectives: The study objective was to estimate a denominator of exposure to inshore lobstering in Full-Time Equivalents (FTEs), to count incident injury data from a sample cohort of this population, to use this count to calculate rates for incident injuries, and to use official counts of fatalities to estimate a fatality rate.Methods: Captains were randomly selected from those licensed to fish in Maine and Massachusetts. Data on work exposure and injuries that occurred on the boat were collected using a survey that was administered once per season via phone or face-to-face interview with the captain. Data included self-reports of the number of weeks worked during the season, average crew size, number of trips per week, and average trip length in hours. In addition, this survey captured relevant information (body segment affected, type of injury, and whether treatment was received) on all acute injuries occurring during the season. Only data on acute injuries were collected, and defined as having newly occurred within the last 3 months. Counts of fatalities were obtained from an official surveillance database at the National Institute for Occupational Health and Safety.Results: The total occupational exposure reported for the cohort was over 2 million man-hours over 4 years, resulting in an average annual FTE of 5,847. The fatality rate averaged over 4 years was 21/100,000 FTE. The incidence rates for all injuries (51.0/100 FTE) and injuries receiving treatment (17.5/100 FTE) were much higher than those reported in other studies of fishing that used US Coast Guard data. Lobstermen presented with all categories of injuries, sprains being the most frequent (7.8/100 FTE) and amputations the least (0.2/100 FTE). Wrist/hand injuries on the right side occurred most frequently of all body locations (3.6/100 FTE).Conclusion: Non-fatal injuries occur at high rates in lobstering. The impact of interventions aimed at exposure to risk for sprains and cuts has potential to affect the most lobstermen. Fatality rate appears to have been unchanging since the year 2000.

Lifejackets and Lobstermen: Giving Safety Equipment a Competitive Advantage.

Background: Falls overboard are the most frequent cause of death in the Northeast lobster fishing industry. National Institute for Occupational Safety and Health (NIOSH) surveillance indicates every victim of a fall overboard who has been found was not wearing a lifejacket. Preliminary research conducted in Maine and Massachusetts indicates lifejacket use is relatively uncommon among lobstermen due to barriers such as comfort, practicality, and social norms.Methods: This study highlights an initiative to: (1) trial various lifejacket designs with lobstermen; (2) identify the most popular designs; and (3) identify other features that could encourage use of lifejackets. In 2017, nine designs were trialed with lobstermen in Maine and Massachusetts during the winter and summer fishing seasons. Participants were recruited dockside, and lifejackets were randomly assigned. Participants completed surveys at 1 week and 4 weeks to assess positive and negative design features and to understand the importance of survival technology that can be used in conjunction with lifejackets.Results: 181 lobstermen in Maine and Massachusetts agreed to participate. Recruitment rates were 90.5%, while the survey completion rate was 88.4%. Survey results identified no clear preference for a specific lifejacket design; however, the ability to choose from many options appeared to be an important factor.Conclusion: Previous studies have indicated that lifejacket preferences are fisheries specific. In the Northeast lobster fishery, however, individual preferences varied. Our research demonstrates that a range of devices covering different buoyancies, wear type, and retrieval systems should be made more available to lobstermen.

Effects of Sublethal Chlorpyrifos Exposure on Postlarval American Lobster (Homarus americanus).

The organophosphate pesticide chlorpyrifos has been introduced to the marine environment via adsorption to agricultural soil runoff or as spray drift. Chlorpyrifos affects the survival of some larval decapod crustaceans, but no data exist on the impacts to the American lobster, Homarus americanus. The purpose of the present study was to assess the levels at which chlorpyrifos affects the survival of postlarval H. americanus. Using acute saltwater exposures, the 24- and 48-h median lethal concentrations were established for stage IV H. americanus (1.56 and 1.33 µg/L, respectively). Movement, acetylcholinesterase activity, intermoult period, specific growth rate, and moult increment were measured during exposure to sublethal concentrations. Movement patterns were assessed to establish a 48-h median inhibition concentration for cessation of normal movement (0.66 µg/L). Acetylcholinesterase activity was found to be inhibited immediately post-exposure to 0.50, 0.57, and 0.82 µg/L chlorpyrifos but could be recovered within a period (9-15 d) in clean seawater. Sublethal growth effects of increased intermoult period, decreased specific growth rate, and decreased moult increment were observed during exposure to an environmentally relevant concentration (0.82 µg/L). The present study suggests that H. americanus stage IV larvae were marginally less sensitive to chlorpyrifos compared with other decapods and that acute lethality of H. americanus postlarvae is not likely to occur with chlorpyrifos concentrations previously reported from aquatic environments. Environ Toxicol Chem 2019;38:1294-1301. © 2019 SETAC.

Rising Temperatures, Molting Phenology, and Epizootic Shell Disease in the American Lobster.

Phenological mismatch-maladaptive changes in phenology resulting from altered timing of environmental cues-is an increasing concern in many ecological systems, yet its effects on disease are poorly characterized. American lobster (Homarus americanus) is declining at its southern geographic limit. Rising seawater temperatures are associated with seasonal outbreaks of epizootic shell disease (ESD), which peaks in prevalence in the fall. We used a 34-year mark-recapture data set to investigate relationships between temperature, molting phenology, and ESD in Long Island Sound, where temperatures are increasing at 0.4°C per decade. Our analyses support the hypothesis that phenological mismatch is linked to the epidemiology of ESD. Warming spring temperatures are correlated with earlier spring molting. Lobsters lose diseased cuticle by molting, and early molting increases the intermolt period in the summer, when disease prevalence is increasing to a fall peak. In juvenile and adult male lobsters, September ESD prevalence was correlated with early molting, while October ESD prevalence was correlated with summer seawater temperature. This suggests that temperature-induced molting phenology affects the timing of the onset of ESD, but later in the summer this signal is swamped by the stronger signal of summer temperatures, which we hypothesize are associated with an increased rate of new infections. October ESD prevalence was ∼80% in years with hot summers and ∼30% in years with cooler summers. Yearly survival of diseased lobsters is <50% that of healthy lobsters. Thus, population impacts of ESD are expected to increase with increasing seawater temperatures.

The effects of emamectin benzoate or ivermectin spiked sediment on juvenile American lobsters (Homarus americanus).

This study examined the effects of a range of ½-log concentrations of emamectin benzoate (commercially applied as SLICE®) and ivermectin (commercially applied as IVOMEC®) on juvenile American lobster, Homarus americanus. Phase I of the research assessed acute (up to 4 days) and chronic (30-day) toxicity of sediment dosed with the active ingredients emamectin benzoate (EMB) formulated as SLICE® or ivermectin (IVM) formulated as IVOMEC® at various nominal concentrations (EMB: 15, 48, 150, 475 and 1500 ng g-1 wet sediment; IVM: 3, 9.5, 30, 95 and 300 ng g-1 wet sediment) on juvenile Atlantic lobster (stages IV). Phase II evaluated sublethal effects (e.g., growth, moulting success) of all lobster surviving past the 30 day exposure period, over an additional 41 days. Chemical analysis of EMB and IVM in sediment samples from the exposure tanks revealed a strong linear association (R2 values 0.99 and 0.98 for EMB and IVM, respectively) between nominal dose and measured concentration of compound. EMB exposure concentrations at very high levels (≥ 343.3 ng g-1) were acutely toxic to juvenile lobster such that 100% of lobsters had died after 13 days of exposure. The maximum cumulative mortality of lobsters exposed to the highest concentrations of EMB and IVM was 100% after 10 days and 25 days, respectively. The 10-day LC50 estimates (±â€¯95% CI) for EMB and IVM were 250.23 ±â€¯90.4 and 212.14 ±â€¯202.64 ng g-1, respectively. Using abnormal behaviour as an indicator, the 15-day EC50 estimates (±â€¯95% CI) for EMB and IVM were 96.19 ±â€¯51.42 and 15.82 ±â€¯6.93 ng g-1, respectively. The NOEC (no observed effect concentration) for abnormal behaviour was 0.0 ng g-1 for each product and the LOEC (lowest observed effect concentration) was 8.8 and > 3.0 ng g-1 for EMB and IVM, respectively. Observations on sublethal effects included delayed moulting to stage VI and reduced growth at higher exposure concentrations for both therapeutants. Using failure to moult to stage V or VI as an indicator, the 15-day EC50 estimates (±â€¯95% CI) for EMB and IVM were 32.72 ±â€¯18.26 and 14.00 ±â€¯12.43 ng g-1, respectively. The NOEC for failure to moult to stage V only was 343.3 and 14.7 ng g-1 for EMB and IVM, respectively. Whereas, the LOEC was 1066.7 and > 61.0 ng g-1 for EMB and IVM, respectively. The concentrations of EMB and IVM tested in the present study were acutely toxic to juvenile lobster exposed to the highest dosages (343.3 and 1066.7 ng EMB g-1 and 61.0 and 300.0 ng IVM g-1). There was significant evidence of chronic toxicity, longer exposure increased mortality with LT50 values decreasing with increasing test material concentration.

Total mercury levels in crustacean species from Italian fishery.

This study investigated mercury contamination levels in eight commercially valuable crustacean species caught off the Central Adriatic and Tyrrhenian coasts of Italy. Total mercury levels were measured by Thermal Decomposition-Amalgamation-Atomic Absorption Spectrophotometry. Results showed a high variability among species with values ranging from 0.070 to 1.24 (mg kg-1 wet weight). The lowest mercury levels were detected in caramote prawn (Penaeus kerathurus), warty crab (Eriphia verrucosa) and European spider crab (Maja squinado), decapods living in shallow waters. Levels exceeding the limits established by the European Commission were found in species living in close contact with bottom sediments: deepwater rose shrimp (Parapenaeus longirostris), blue and red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). For shrimps, the inter-individual variability observed was mostly related to the body size, indicating the accumulation of mercury with age. An estimation of the human intake of mercury associated to the consumption of the crustaceans sampled and its comparison with the Tolerable Weekly Intake are provided.

Relative Quantitation of Neuropeptides at Multiple Developmental Stages of the American Lobster Using N, N-Dimethyl Leucine Isobaric Tandem Mass Tags.

Neuromodulators and neurotransmitters play important roles in neural network development. The quantitative changes of these signaling molecules often reflect their regulatory roles in physiological processes. Currently, several commercial tags (e.g., iTRAQ and TMT) have been widely used in proteomics. With reduced cost and higher labeling efficiency, we employed a set of custom-developed N, N-dimethyl leucine (DiLeu) 4-plex isobaric tandem mass tags as an attractive alternative for the relative quantitation of neuropeptides in brain tissue of American lobster Homarus americanus at multiple developmental stages. A general workflow for isobaric labeling of neuropeptides followed by LC-MS/MS analysis has been developed, including optimized sample handling procedures. Overall, we were able to quantify 18 trace-amount neuropeptides from 6 different families using a single adult brain as a control. The quantitation results indicated that the expressions of different neuropeptide families had significant changes over distinct developmental stages. Additionally, our data revealed intriguing elevated expression of neuropeptides in the early juvenile development stage. The methodology presented here advanced the workflow of DiLeu as an alternative labeling approach and the application of DiLeu-based quantitative peptidomics, which can be extended to areas beyond neuroscience.

Homarus gammarus (Crustacea: Decapoda) larvae under an ocean acidification scenario: responses across different levels of biological organization.

The present study evaluated the effects of exposure to different target pCO2 levels: control (C: 370µatm, pH=8.15) and ocean acidification (OA: 710µatm, pH=7.85) on development and biochemical responses related with oxidative stress and energy metabolism during the crustacean Homarus gammarus (L.) larval development, integrating different levels of biological organization. After hatching in the laboratory, larvae from the same female brood were exposed to the described conditions from hatching until reaching Stage III (last larval stage - 11days). H. gammarus larvae demonstrated some susceptibility when addressing the predicted pCO2 levels for 2100. Further analysis at the biochemical and physiological level highlighted the occurrence of oxidative stress in the OA scenario (Superoxide Dismutase reduction and higher DNA damage) that was followed by developmental effects, increased inter-moult period from SII to SIII and reduced growth. The extended exposure to these conditions may affect organisms' key life-cycle functions such as physiological resistance, growth, sexual maturation, or reproduction with implications in their future fitness and population dynamics.

Prediction of a neuropeptidome for the eyestalk ganglia of the lobster Homarus americanus using a tissue-specific de novo assembled transcriptome.

In silico transcriptome mining is a powerful tool for crustacean peptidome prediction. Using homology-based BLAST searches and a simple bioinformatics workflow, large peptidomes have recently been predicted for a variety of crustaceans, including the lobster, Homarus americanus. Interestingly, no in silico studies have been conducted on the eyestalk ganglia (lamina ganglionaris, medulla externa, medulla interna and medulla terminalis) of the lobster, although the eyestalk is the location of a major neuroendocrine complex, i.e., the X-organ-sinus gland system. Here, an H. americanus eyestalk ganglia-specific transcriptome was produced using the de novo assembler Trinity. This transcriptome was generated from 130,973,220 Illumina reads and consists of 147,542 unique contigs. Eighty-nine neuropeptide-encoding transcripts were identified from this dataset, allowing for the deduction of 62 distinct pre/preprohormones. Two hundred sixty-two neuropeptides were predicted from this set of precursors; the peptides include members of the adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin B, allatostatin C, bursicon α, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone (CHH), CHH precursor-related peptide, diuretic hormone 31, diuretic hormone 44, eclosion hormone, elevenin, FMRFamide-like peptide, glycoprotein hormone α2, glycoprotein hormone ß5, GSEFLamide, intocin, leucokinin, molt-inhibiting hormone, myosuppressin, neuroparsin, neuropeptide F, orcokinin, orcomyotropin, pigment dispersing hormone, proctolin, pyrokinin, red pigment concentrating hormone, RYamide, short neuropeptide F, SIFamide, sulfakinin, tachykinin-related peptide and trissin families. The predicted peptides expand the H. americanus eyestalk ganglia neuropeptidome approximately 7-fold, and include 78 peptides new to the lobster. The transcriptome and predicted neuropeptidome described here provide new resources for investigating peptidergic signaling within/from the lobster eyestalk ganglia.

Growth in Nephrops norvegicus from a tag-recapture experiment.

Nephrops norvegicus is a commercially valuable fishery in the EU but management of stocks is challenging due to difficulties in aging individuals and calculating growth and biomass production. Growth of N. norvegicus was estimated by releasing 1177 tagged individuals in western Ireland in Summer 2013 and recapturing these in 2014 (n = 207, an average of 344 days later) and 2015 (n = 38, 654-665 days later). Moulting occurred twice per year in approximately half of the males and only once in females. Mean growth increments after approximately one year were 5.1 mm Carapace Length (CL) in males and 1.4 mm CL in females. After two years, males had grown by 12.0 mm CL and females by 4.6 mm CL, on average, across size classes. Low variation in growth increments was seen across female size classes, but significantly lower growth was observed in larger males, meeting an important assumption of the Von Bertalanffy Growth Function. Asymptotic carapace lengths were 70.8 mm (males) and 55.2 mm (females) with respective growth constants (k) of 0.161 yr-1 and 0.077 yr-1. The results suggest that this is a very productive fishery and that survivability of returns from creel fishing is high.

Long-term microplastic retention causes reduced body condition in the langoustine, Nephrops norvegicus.

Microplastic represents a rising proportion of marine litter and is widely distributed throughout a range of marine habitats. Correspondingly, the number of reports of species containing microplastics increases annually. Nephrops norvegicus in the Firth of Clyde have previously been shown to retain large aggregations of microplastic fibres. The potential for N. norvegicus to retain plastic over an extended time period increases the likelihood of any associated negative impacts to the individual. This study represents the longest observation of the impacts of microplastic retention in invertebrates. We exposed N. norvegicus to plastic over eight months to determine the impacts of extended exposure. Over this period we compared the feeding rate, body mass, and nutritional state of plastic-fed N. norvegicus to that of fed and starved control groups. Following the experimental period, the plastic-fed langoustine contained microplastic aggregations comparable to those of small individuals from the Clyde Sea Area. Comparisons between fed, unfed and plastic-fed individuals indicated a reduction in feeding rate, body mass, and metabolic rate as well as catabolism of stored lipids in plastic contaminated animals. We conclude that N. norvegicus exposed to high levels of environmental microplastic pollution may experience reduced nutrient availability. This can result in reduced population stability and may affect the viability of local fisheries.

Distribution of two species of Nephropsis Wood-Mason, 1872 (Crustacea, Decapoda, Nephropidae) from northeastern Brazil.

The genus Nephropsis Wood-Mason, 1872 has been reported from Brazil by Tavares (1998), Tavares & Young (2002), Silva et al. (2003), Dall´Occo et al. (2007) and Serejo et al. (2007), recording Nephropsis aculeata Smith, 1881, N. rosea Bate, 1888 and N. agassizii A. Milne-Edwards, 1880, the last of which occurs in both northeastern and southeastern of Brazil.

Assessing Fish and Motile Fauna around Offshore Windfarms Using Stereo Baited Video.

There remains limited knowledge of how offshore windfarm developments influence fish assemblages, particularly at a local scale around the turbine structures. Considering the existing levels of anthropogenic pressures on coastal fish populations it is becoming increasingly important for developers and environmental regulators to gain a more comprehensive understanding of the factors influencing fish assemblages. Improving our ability to assess such fish populations in close proximity to structures will assist in increasing this knowledge. In the present study we provide the first trial use of Baited Remote Underwater Stereo-Video systems (stereo BRUVs) for the quantification of motile fauna in close proximity to offshore wind turbines. The study was conducted in the Irish Sea and finds the technique to be a viable means of assessing the motile fauna of such environments. The present study found a mixture of species including bottom dwellers, motile crustaceans and large predatory fish. The majority of taxa observed were found to be immature individuals with few adult individuals recorded. The most abundant species were the angular crab (Goneplax rhomboides) and the small-spotted catshark (Scyliorhinus canicula). Of note in this study was the generally low abundance and diversity of taxa recorded across all samples, we hypothesise that this reflects the generally poor state of the local fauna of the Irish Sea. The faunal assemblages sampled in close proximity to turbines were observed to alter with increasing distance from the structure, species more characteristic of hard bottom environments were in abundance at the turbines (e.g. Homarus gammarus, Cancer pagarus, Scyliorhinus spp.) and those further away more characteristic of soft bottoms (e.g. Norwegian Lobster). This study highlights the need for the environmental impacts of offshore renewables on motile fauna to be assessed using targeted and appropriate tools. Stereo BRUVs provide one of those tools, but like the majority of methods for sampling marine biota, they have limitations. We conclude our paper by providing a discussion of the benefits and limitations of using this BRUV technique for assessing fauna within areas close to offshore windfarms.

De novo transcriptome assembly for the lobster Homarus americanus and characterization of differential gene expression across nervous system tissues.

BACKGROUND: The American lobster, Homarus americanus, is an important species as an economically valuable fishery, a key member in marine ecosystems, and a well-studied model for central pattern generation, the neural networks that control rhythmic motor patterns. Despite multi-faceted scientific interest in this species, currently our genetic resources for the lobster are limited. In this study, we de novo assemble a transcriptome for Homarus americanus using central nervous system (CNS), muscle, and hybrid neurosecretory tissues and compare gene expression across these tissue types. In particular, we focus our analysis on genes relevant to central pattern generation and the identity of the neurons in a neural network, which is defined by combinations of genes distinguishing the neuronal behavior and phenotype, including ion channels, neurotransmitters, neuromodulators, receptors, transcription factors, and other gene products. RESULTS: Using samples from the central nervous system (brain, abdominal ganglia), abdominal muscle, and heart (cardiac ganglia, pericardial organs, muscle), we used RNA-Seq to characterize gene expression patterns across tissues types. We also compared control tissues with those challenged with the neuropeptide proctolin in vivo. Our transcriptome generated 34,813 transcripts with known protein annotations. Of these, 5,000-10,000 of annotated transcripts were significantly differentially expressed (DE) across tissue types. We found 421 transcripts for ion channels and identified receptors and/or proteins for over 20 different neurotransmitters and neuromodulators. Results indicated tissue-specific expression of select neuromodulator (allostatin, myomodulin, octopamine, nitric oxide) and neurotransmitter (glutamate, acetylcholine) pathways. We also identify differential expression of ion channel families, including kainite family glutamate receptors, inward-rectifying K(+) (IRK) channels, and transient receptor potential (TRP) A family channels, across central pattern generating tissues. CONCLUSIONS: Our transcriptome-wide profiles of the rhythmic pattern generating abdominal and cardiac nervous systems in Homarus americanus reveal candidates for neuronal features that drive the production of motor output in these systems.

First record of the Nephropid genus Acanthacaris Bate, 1888 (Crustacea: Decapoda: Nephropidae) from Taiwan.

The giant deep-sea lobster genus Acanthacaris Bate, 1888 is reported for the first time from Taiwan. The single specimen with a total length of 36 cm was collected near a cold seep off southwestern Taiwan at about 1300 m deep and identified as A. tenuimana Bate, 1888.