A bibliography of the lobster and the spiny lobster, families Homaridae and Palinuridae.

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Lobster salad,

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Esterified astaxanthin levels in lobster epithelia correlate with shell colour intensity: Potential role in crustacean shell colour formation

Carotenoids, particularly astaxanthin, are the primary pigment in crustacean shell colour. Sub-adults of the western rock lobster, Panulirus cygnus, moult from a deep red colour (termed the red phase) to a much paler colour (the white phase) at sexual maturation. We observe a 2.4-fold difference in the amount of total carotenoid present in the shell extracts of reds compared to whites, as might be expected. However, analysis of the underlying epithelium shows that there is no correlation with shell colour and the amount of free (unesterified) astaxanthin-the level of free astaxanthin in reds and whites is not significantly different. Instead, we observe a correlated two-fold difference in the amount of esterified astaxanthin present in the epithelium of red versus white individuals. These data suggest a role for esterified astaxanthin in regulating shell colour formation and suggest that esterification may promote secretion and eventual incorporation of unesterified astaxanthin into the exoskeleton. (c) 2005 Elsevier Inc. All rights reserved.

Microbial diversity within the water column of a larval rearing system for the ornate rock lobster (Panulirus ornatus)

The ornate tropical rock lobster, Panulirus ornatus has substantial potential as an aquaculture species though disease outbreaks during the animal's extended larval lifecycle are major constraints for success. In order to effectively address such disease-related issues, an improved understanding of the composition and dynamics of the microbial communities in the larval rearing tanks is required. This study used flow cytometry and molecular microbial techniques (clone libraries and denaturing gradient gel electrophoresis (DGGE)) to quantify and characterise the microbial community of the water column in the early stages (developmental stage I-II) of a P. ornatus larval rearing system. DGGE analysis of a 5000 L larval rearing trial demonstrated a dynamic microbial community with distinct changes in the community structure after initial stocking (day I to day 2) and from day 4 to day 5, after which the structure was relatively stable. Flow cytometry analysis of water samples taken over the duration of the trial demonstrated a major increase in bacterial load leading up to and peaking on the first day of the initial larval moult (day 7), before markedly decreasing prior to when > 50% of larvae moulted (day 9). A clone library of a day 10 water sample taken following a mass larval mortality event reflected high microbial diversity confirmed by statistical analysis indices. Sequences retrieved from both clone library and DGGE analyses were dominated by gamma- and alpha-Proteobacteria affiliated organisms with additional sequences affiliated with beta- and epsilon-Proteobacteria, Bacteroidetes, Cytophagales and Chlamydiales groups. Vibrio affiliated species were commonly retrieved in the clone library, though absent from DGGE analysis.

European lobster (Homarus gammarus) larvae under an acidification scenario: addressing biochemical, development and behaviour responses

A acidificação dos oceanos constitui uma problemática global e a realidade de que está, efetivamente, a acontecer não é uma consideração subjetiva. A Acidificação dos oceanos provocada por emissões de dióxido de carbono de origem antropogénica tem vindo a reduzir o pH das águas superficiais do Oceano e projeções preveem a continuidade deste processo. Embora muita investigação tenha sido desenvolvida no âmbito dos invertebrados que calcificam, tais como moluscos e crustáceos, poucos consideraram o estudo de efeitos ao nível sub-celular para avaliar stress oxidativo ou respostas funcionais do metabolismo energético em tais condições, interligando vários níveis de organização biológica. O objetivo do presente estudo foi o de avaliar os efeitos da exposição a diferentes níveis-alvo de pCO2 (controlo: 370 μatm; aumentado: 710 μatm) e de pH (controlo: 8.15; reduzido: 7.85) em parâmetros de crescimento bem como avaliar respostas comportamentais e bioquímicas relacionadas com stress oxidativo e metabolismo energético durante o desenvolvimento larvar de um crustáceo decápode. Este cenário de acidificação está de acordo com os RCPs previstos pelo Painel Intergovernamental para as Alterações Climáticas (IPCC, 2014) para o ano 2100. Para o presente estudo, foi utilizado o crustáceo Homarus gammarus (L.) – sendo uma espécie com elevado valor comercial, que tem vindo a sofrer elevada pressão de pesca em águas Europeias. Fêmeas adultas provenientes da costa Atlântica Oeste Portuguesa foram obtidas de um retalhista local. Após a eclosão em ambiente laboratorial controlado, larvas provenientes da mesma progenitora foram expostas às condições acima descritas desde o momento da eclosão até à chegada ao Estádio III. A sobrevivência individual e ocorrência de ecdise foram avaliados individualmente de 12h em 12h. Réplicas de cada tratamento foram recolhidas em momentos específicos durante o Estádio I (primeiro estádio larvar) e Estádio III (último estádio larvar) para análise morfométrica e de crescimento (peso fresco e comprimento carapaça) e respostas bioquímicas. Os biomarcadores analisados incluíram parâmetros relacionados com stress oxidativo e danos (atividade da enzima superóxido dismutase (SOD), peroxidação lipídica (LPO) e danos no DNA) e metabolismo energético (atividade da cadeia transportadora de eletrões (ETS) e da enzima lactato desidrogenase (LDH) e quantificação de Hidratos de Carbono). Os resultados obtidos sugerem que a sobrevivência diminui e que o período inter-muda é afetado durante a exposição a cenários de acidificação. No que respeita aos parâmetros de crescimento/morfométricos, larvas do cenário de acidificação apresentam uma tendência para crescimento diminuído, menor peso e comprimento de carapaça. As análises bioquímicas realizadas indicam a ocorrência de stress oxidativo sob condições de acidificação. Respostas ao nível do metabolismo energético não variaram significativamente entre tratamentos. Os resultados apontam também para que fases larvares possam possuir um sistema antioxidante ainda em desenvolvimento, tornando-as mais suscetíveis ao stress oxidativo. As fases larvares são uma fase vulnerável e crucial no ciclo de vida das espécies, influenciando o recrutamento e a renovação de stocks. Este estudo contribui para um melhor entendimento sobre a vulnerabilidade desta espécie num cenário de alterações climáticas – Acidificação dos oceanos – ao endereçar os mecanismos envolvidos nas respostas deste crustáceo a este agente causador de stress.

Size selectivity of diamond and square mesh cod ends for rose shrimp (Parapenaeus longirostris) and Norway lobster (Nephrops norvegicus) off the Portuguese south coast

The effects of an increase in cod end mesh size from 55 to 60 and 70 mm and a change of mesh configuration from diamond to square mesh on the size selectivity for rose shrimp Parapenaeus longirostris and Norway lobster Nephrops norvegicus captured off the Portuguese south coast were evaluated. The results were analysed taking into account between-haul variation in selectivity, and indicate a significant increase in L-50 for rose shrimp with an increase in mesh size or with the use of a square mesh cod end, while for Norway lobster only mesh configuration was found to affect this parameter. Two other important external variables were identified; the trawling depth and the cod end catch, which influence between-haul variation, by increasing the selection range for rose shrimp and Norway lobster, respectively. The results obtained suggest that an increase in the current minimum mesh size of 55 mm would be advisable for rose shrimp in order to respect the minimum landing size of 24 mm carapace length presently established for this species. Moreover, trawling for rose shrimp should be avoided at depths above 200 m, in order to avoid catches consisting almost exclusively of juveniles. Such an increase in mesh size would have a minor impact in terms of losses of individuals above the minimum landing size for Norway lobster and would contribute to reducing the amount of discards in this fishery. (C) 2002 Elsevier Science B.V. All rights reserved.

Innate Immunity in Lobsters: Partial Purification and Characterization of a Panulirus cygnus Anti-A Lectin

A lectin detected in haemolymph from the Australian spiny lobster Panulirus cygnus agglutinated human ABO Group A cells to a higher titre than Group O or B. The lectin also agglutinated rat and sheep erythrocytes, with reactivity with rat erythrocytes strongly enhanced by treatment with the proteolytic enzyme papain, an observation consistent with reactivity via a glycolipid. The lectin, purified by affinity chromatography on fixed rat-erythrocyte stroma, was inhibited equally by N-acetylglucosamine and N-acetylgalactosamine. Comparison of data from gel filtration of haemolymph (behaving as a 1,800,000 Da macromolecule), and polyacrylamide gel electrophoresis of purified lectin (a single 67,000 Da band), suggested that in haemolymph the lecin was a multimer. The purified anti-A lectin autoprecipitated unless the storage solution contained chaotropic inhibitors (125 mmol/L sucrose: 500 mmol/L urea). The properties of this anti-A lectin and other similar lectins are consistent with a role in innate immunity in these invertebrates.

A quantitative metric to identify critical elements within seafood supply networks

A theoretical basis is required for comparing key features and critical elements in wild fisheries and aquaculture supply chains under a changing climate. Here we develop a new quantitative metric that is analogous to indices used to analyse food-webs and identify key species. The Supply Chain Index (SCI) identifies critical elements as those elements with large throughput rates, as well as greater connectivity. The sum of the scores for a supply chain provides a single metric that roughly captures both the resilience and connectedness of a supply chain. Standardised scores can facilitate cross-comparisons both under current conditions as well as under a changing climate. Identification of key elements along the supply chain may assist in informing adaptation strategies to reduce anticipated future risks posed by climate change. The SCI also provides information on the relative stability of different supply chains based on whether there is a fairly even spread in the individual scores of the top few key elements, compared with a more critical dependence on a few key individual supply chain elements. We use as a case study the Australian southern rock lobster Jasus edwardsii fishery, which is challenged by a number of climate change drivers such as impacts on recruitment and growth due to changes in large-scale and local oceanographic features. The SCI identifies airports, processors and Chinese consumers as the key elements in the lobster supply chain that merit attention to enhance stability and potentially enable growth. We also apply the index to an additional four real-world Australian commercial fishery and two aquaculture industry supply chains to highlight the utility of a systematic method for describing supply chains. Overall, our simple methodological approach to empirically-based supply chain research provides an objective method for comparing the resilience of supply chains and highlighting components that may be critical.