Marine Crustacea Research Articles

A systematic review on microplastic contamination in marine Crustacea and Mollusca of Asia: Current scenario, concentration, characterization, polymeric risk assessment, and future Prospectives.

Microplastics (MPs) pollution has wreaked havoc on biodiversity and food safety globally. The false ingestion of MPs causes harmful effects on organisms, resulting in a decline in biodiversity. The present review comprehended the current knowledge of MP contamination in Crustacea and Mollusca from 75 peer-reviewed articles published in Asia between 2015 and 2023. A total of 79 species (27 Crustacea and 52 Mollusca) have been recorded to be contaminated with MPs. Out of the total 27 species of Crustacea, Metopograpsus quadridentatus (327.56 MPs/individual) and Balanus albicostatus (0.42 MPs/individual) showed the highest and lowest contamination, respectively. Out of the total 52 species of Mollusca, Dolabella auricularia (2325 MPs/individual) and Crassostrea gigas and Mytilus edulis (0.2 MPs/individual) showed the highest and lowest contamination, respectively. In terms of country-wise MP contamination, China has the highest number of contaminated species in both phylums among Asia. Findings of pollution indices revealed a very high risk of MP contamination in all the countries. Fiber was reported predominantly in both groups. Blue and black-colored MPs having <500 μm and <500 μm-1mm size were found dominantly in Crustacea and Mollusca, respectively. Polypropylene was recorded as the dominant plastic polymer in both Crustacea and Mollusca. In essence, this review has provided a comprehensive insight into MP concentration in Crustacea and Mollusca of Asia, highlighting variations among species and geographic locations. This understanding is crucial for tackling urgent environmental challenges, safeguarding human health, and promoting global sustainability initiatives amid the escalating issue of plastic pollution. PRACTITIONER POINTS: Microplastic pollution has created havoc on biodiversity and food safety. A total of 27 and 52 species of crustaceans and Mollusca have been recorded to be contaminated with MPs. Metopograpsus quadridentate and Dolabella auricularia have shown higher MPs contamination. Polypropylene was recorded as the dominant plastic polymer in both crustacean and Mollusca. Findings of pollution indices revealed a very high risk of MP contamination in all the countries.

Preliminary hazard assessment of a new nature-inspired antifouling (NIAF) agent

A recently synthesized aminated 3,4-dioxygenated xanthone (Xantifoul2) was found to have promising antifouling (AF) effects against the settlement of the macrofouler Mytilus galloprovincialis larvae. Preliminary assessment indicated that Xantifoul2 has reduced ecotoxicological impacts: e.g., being non-toxic to the marine crustacea Artemia salina (<10 % mortality at 50 μM) and showing low bioconcentration factor in marine organisms. In order to meet the EU Biocidal Product Regulation, a preliminary hazard assessment of this new nature-inspired antifouling (NIAF) agent was conducted in this work. Xantifoul2 did not affect the swimming ability of the planktonic crustacean Daphnia magna, the growth of the diatom Phaeodactylum tricornutum, and the cellular respiration of luminescent Gram-negative bacteria Vibrio fischeri, supporting the low toxicity towards several non-target marine species. Regarding human cytotoxicity, Xantifoul2 did not affect the cell viability of retinal human cells (hTERT-RPE-1) and lipidomic studies revealed depletion of lipids involved in cell death, membrane modeling, lipid storage, and oxidative stress only at a high concentration (10 μM). Accelerated degradation studies in water were conducted under simulated sunlight to allow the understanding of putative transformation products (TPs) that could be generated in the aquatic ecosystems. Both Xantifoul2 and photolytic-treated Xantifoul2 in the aqueous matrix were therefore evaluated on several nuclear receptors (NRs). The results of this preliminary hazard assessment of Xantifoul2, combined with the high degradation rates in water, provide strong evidence of the safety of this AF agent under the evaluated conditions, and provide the support for future validation studies before this compound can be introduced in the market.

Microstructure, mechanical properties and elemental composition of the terrestrial isopod Armadillidium vulgare cuticle

The exoskeletons of crustaceans are essential for providing protection from predators and other environmental threats. Understanding the structure and mechanical behavior of their natural armor could inspire the design of lightweight and high toughness synthetic materials. Most published work has focused on marine crustacea rather than their terrestrial counterparts, which are exposed to a multitude of unique threats. The interest in the terrestrial isopod Armadillidium vulgare (A. vulgare) has grown but the interrelationship between the microstructure, chemical composition, and mechanical properties has not been thoroughly investigated. Thus, this study aims to elucidate missing details concerning this biological mineralized composite. Exoskeleton specimens were fixated to preserve the intrinsic protein structure. We utilize scanning electron microscopy for microstructure analysis, Raman spectroscopy for elemental analysis, and nanoindentation property mapping to achieve mechanical characterization. The naturally fractured A. vulgare exoskeleton cross-section reveals four subregions with the repeating helicoidal ‘Bouligand’ arrangement most prominent in the endocuticle. The hardness and reduced modulus distributions exhibit a through-thickness exponential gradient with decreasing magnitudes from the outermost to the innermost layers of the exoskeleton. The Raman spectra show a graded spatial distribution of key constituents such as calcium carbonate across the thickness, some of which are consistent with the mechanical property gradient. Potential microstructure, elemental composition, and mechanical property relationships are discussed to explain how the hierarchical structure of this nanolaminate armor protects this species.

What evidence exists for the impact of climate change on the physiology and behaviour of important aquaculture marine crustacean species in Asia? A systematic map protocol

BackgroundClimate is one of the most important driving factors of future changes in terrestrial, coastal, and marine ecosystems. Any changes in these environments can significantly influence physiological and behavioural responses in aquatic animals, such as crustacea. Crustacea play an integral role as subsistence predators, prey, or debris feeders in complex food chains, and are often referred to as good indicators of polluted or stressed conditions. They also frequently have high production, consumption, and commercial significance. However, crustacean’s responses to climate change are likely to vary by species, life-history stage, reproduction status and geographical distribution. This map is undertaken as part of the Long-Term Research Grant project which aims to identify any interactive effect on physiological compensation and behavioural strategy of how marine organisms, especially crustaceans, deal with stress from environmental change. Our proposed map will aim to outline the evidence currently existing for the impacts of climate change on the physiology and behaviour of important aquaculture crustacean species within Asia.MethodsWe will document peer-reviewed articles in English using published journal articles and grey literature. Two bibliographic databases (Scopus and Web of Science) and multiple organizational websites with Google scholars will be searched. The systematic map protocol will follow in accordance with the Collaboration for Environmental Evidence Guidelines and Standards. Literature will be screened at the title, abstract, and full-text level using pre-defined inclusion criteria. The map will highlight marine crustacea physiological compensation and behavioural strategies to cope with climate change. It will also improve our knowledge of the available evidence and current gaps for future research recommendations.

Environmental matching reveals non-uniform range-shift patterns in benthic marine Crustacea

Empirical and theoretical studies suggest that marine species respond to ocean warming by shifting ranges poleward and/or into deeper depths. However, future distributional patterns of deep-sea organisms, which comprise the largest ecosystem of Earth, remain poorly known. We explore potential horizontal range shifts of benthic shallow-water and deep-sea Crustacea due to climatic changes within the remainder of the century, and discuss the results in light of species-specific traits related to invasiveness. Using a maximum entropy approach, we estimated the direction and magnitude of distributional shifts for 94 species belonging to 12 orders of benthic marine crustaceans, projected to the years 2050 and 2100. Distance, direction, and species richness shifts between climate zones were estimated conservatively, by considering only areas suitable, non-extrapolative, and adjacent to the currently known distributions. Our hypothesis is that species will present poleward range-shifts, based on results of previous studies. Results reveal idiosyncratic and species-specific responses, with prevailing poleward shifts and a decline of species richness at mid-latitudes, while more frequent shifts between temperate to polar regions were recovered. Shallow-water species are expected to shift longer distances than deep-sea species. Net gain of suitability is slightly higher than the net loss for shallow-water species, while for deep-sea species, the net loss is higher than the gain in all scenarios. Our estimates can be viewed as a set of hypotheses for future analytical and empirical studies, and will be useful in planning and executing strategic interventions and developing conservation strategies.

Disease monitoring of wild marine fish and crustacea caught from inshore and offshore Korea in 2018

Disease monitoring of wild marine fish and crustacea caught from inshore and offshore Korea in 2018

Pathogens and other symbionts of the Amphipoda: taxonomic diversity and pathological significance.

With over 10000 species of Amphipoda currently described, this order is one of the most diverse groups of freshwater and marine Crustacea. Members of this group are globally distributed, and many are keystone species and ecosystem engineers within their respective ecologies. As with most organisms, disease is a key factor that can alter population size, behaviour, survival, invasion potential and physiology of amphipod hosts. This review explores symbiont diversity and pathology in amphipods by coalescing a range of current and historical literature to provide the first full review of our understanding of amphipod disease. The review is broken into 2 parts. The first half explores amphipod microparasites, which include data pertaining to viruses, bacteria, fungi, oomycetes, microsporidians, dinoflagellates, myxozoans, ascetosporeans, mesomycetozoeans, apicomplexans and ciliophorans. The second half reports the metazoan macroparasites of Amphipoda, including rotifers, trematodes, acanthocephalans, nematodes, cestodes and parasitic Crustacea. In all cases we have endeavoured to provide a complete list of known species that cause disease in amphipods, while also exploring the effects of parasitism. Although our understanding of disease in amphipods requires greater research efforts to better define taxonomic diversity and host effects of amphipod symbionts, research to date has made huge progress in cataloguing and experimentally determining the effects of disease upon amphipods. For the future, we suggest a greater focus on developing model systems that use readily available amphipods and diseases, which can be comparable to the diseases in other Crustacea that are endangered, economically important or difficult to house.

Preliminary Characterization of Occipodins, Natural Product Anticoagulants from Hematophagous Marine Parasites, Isopod Elthusa vulgaris and Copepod Phrixocephalus Cincinnatus.

We report identification and preliminary characterization of novel proteinaceous anticoagulants from two marine crustacea, Elthusa vulgaris and Phrixocephalus cincinnatus. We also propose naming them Occipodins in honor of the college where this undergraduate research has been initiated. The organisms were collected at 25-125 meters depth off the coast of Los Angeles. Both organisms are hematophagous arthropods that anchor onto their host species and induce the extravasation of host blood into their digestive organs. Female P. cincinnatus display host specificity infecting the eyes of flatfish by anchoring to the choroid membrane and subsequently developing rami, an elaborate dendritic network, that facilitates the ingestion of extravasated blood from retinal blood vessels (Figure 1). The described species E. vulgaris is an isopod that similarly parasitizes a variety of marine fish by anchoring to the blood-rich gill filaments of their hosts (Figure 2). The accumulation of blood and attenuation of coagulation responses visually observed in the copepod trunk prompted us to initiate the identification of the anticoagulant factors in both hematophagous marine species.A crude cellular extract was prepared by homogenizing 10 specimens with a mortar and pestle frozen in liquid nitrogen resulting in a fine powder. The homogenate was resuspended in 15ml of 50mM Hepes buffer, pH7.4, containing 150mM NaCl and 3mM CaCl2 and mixed on a rotary shaker for 20min at room temperature. The resulting tissue suspension was centrifuged at 15,000xg 15 min and the supernatant was filtered through a 0.2 μm syringe filter. 10μl aliquots of extracts were used for all anticoagulant activity tests using FACT plasma for aPTT and PT assays on a Stago STart 4 hemostasis analyzer (Table 1). The extracts from both parasites were found to have exclusive anticoagulation activity on the intrinsic pathway (APTT assay) but no prolongation of coagulation time was observed in PT assays. Several biochemical tests were employed to further characterize the occipodins. First, size exclusion tests were performed using series of Millipore centrifugal filter units ranging from 10 to 100kD molecular weight cutoff. The size of the occipodin from P. cincinnatus was determined to be larger than 100kD while the anticoagulant isolated from Elthusa was estimated to be ~50kD. In order to identify whether these large macromolecules require a folded structure for activity we employed heat denaturation tests at 96°C for 15min. The P. cincinnatus occipodin showed substantial loss of anticoagulant activity following heat denaturation while E. vulgaris retained some residual anticoagulant activity, indicating the presence of non-proteinaceous, heat-resistant components (Table 1).A preliminary purification procedure of the anticoagulant isolated from Elthusa was established using a DEAE anion exchange chromatography. The crude tissue extract was diluted two fold with 50mM Hepes buffer, pH7.4 and applied on a 22ml column packed with DEAE-Sephacel (GE Healthcare) anion exchange matrix equilibrated with 50mM HEPES buffer, pH 7.4, containing 75mM NaCl. To elute occipodins, a step gradient ranging from 150 to 500mM NaCl (in the same HEPES buffer) was applied, after an extensive washing step with 120ml equilibration buffer. The anticoagulant activity was detected in fractions eluted between 125mM and 500mM NaCl with main pick centered at fractions eluted with buffer containing 150mM NaCl (Table 2)Identification of the site of inhibitory action of occipodins on the intrinsic coagulation pathway is currently in progress. In addition, further experiments will be targeted towards purification of occipodins and identification of their partial amino acid sequences. This sequence information will be used for cloning of cDNAs encoding these proteins. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A checklist of marine crustaceans known from Easter Island

Easter Island constitutes the most isolated terrestrial ecosystem in the Pacific Ocean. The fauna of that site is interesting from a biogeographical point of view because species from Pacific Asia and South America can be found there, as well as endemic species. The aim of the present study was to compile a literature review of published records of marine Crustacea from Easter Island with the emphasis on the heterogeneity in habitats reported for each species. The results confirm the presence of species otherwise known from Pacific Asia, South America, as well as the expected endemic species. In spite of the little information that is generally provided in the habitat records for most species, it may still be possible to find a marked heterogeneity of ecosystems, together generating a complex system that warrants more detailed studies.

A review of cnidarian epibionts on marine crustacea

Abstract An updated inventory of the cnidarian species living as epibionts on Crustacea was conducted. Cnidarian species that attach themselves to gastropod shells of hermit crabs were also considered. One hundred and forty-eight species of cnidaria were included, with similar numbers of hydrozoans and anthozoans. There were 163 basibiont species that were mostly decapod species. The presence of these epibionts on different crustacean species and their taxonomic positions were indicated. This review is intended to serve as a useful tool for future studies of this type of epibiosis.

Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?

BackgroundSeveral lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide.ResultsThe primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea.ConclusionsIn parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.

Global bottlenecks in the distribution of marine Crustacea: temperature constraints in the family Lithodidae

AbstractAim Members of the crustacean family Lithodidae share preferences for cold‐water environments; however, the specific role of temperature in governing lithodid biogeography has not been examined to date. In the present study this relationship was quantified through the analysis of habitat data, and the results were interpreted in the light of previous physiological studies. It was hypothesized that lineage‐specific temperature thresholds underlie differences in the distribution of the two lithodid subfamilies.Location The family Lithodidae is divided into the subfamilies Hapalogastrinae and Lithodinae. The Hapalogastrinae inhabit depths of between 0 and 200 m in the North Pacific. The Lithodinae are distributed globally in the deep sea, with a few genera occurring intertidally at high latitudes.Methods Descriptions of 86 species of lithodids, sampled at 627 locations worldwide, were obtained from a wide range of published and original sources. For each specimen, the water temperature at the time and locality of collection was recorded. Molecular sequence data for the 16S, cytochrome c oxidase subunit I (COI) and 28S genes were analysed to construct a phylogenetic tree for the major lithodid genera, using a maximum likelihood method in the program paup*. Further analyses examined the link between the habitat temperature range and the position of taxa within the lithodid phylogeny.Results Phylogenetic evidence indicated that the deep‐water lithodid lineages had ancestors that inhabited the coastal waters of the North Pacific. Adults of North Pacific lithodid taxa were found in regions where water temperatures ranged from 0 to 25°C; however, deep‐water lineages of the Lithodinae were excluded from waters exceeding temperatures of 13°C. Despite the higher temperatures tolerated by adults, North Pacific intertidal/subtidal genera were restricted to regions that had water temperatures lower than 16°C during periods of larval development.Main conclusions Temperature has restricted the range of most shallow‐water genera of Lithodidae to the coastline of the North Pacific since the early history of the family. Distribution in these groups remains constrained by the detrimental effects of temperature extremes on early life‐history stages. Deep‐water lineages moved away from seasonal temperature fluctuations, and underwent at least three radiations into water bodies outside the North Pacific. Species from within the deep‐water lineages currently live close to the threshold of their temperature tolerance in the Southern Ocean, and their future distribution may be affected by increases in ocean temperature.

Crustacea of the Cayman Islands, British West Indies II. Heteromysis (Olivemysis) ebanksae, a new species (Mysida: Mysidae) from Little Cayman and Grand Cayman Islands

ABSTRACT During a survey of the marine Crustacea of the Cayman Islands, Heteromysis ebanksae, new species was discovered in depths of 1–3 m adjacent to Little Cayman Island and from North Sound, Grand Cayman Island. The new species, which belongs to the subgenus Olivemysis Bacescu, 1968, collected from live bottom and sea grass habitats, is distinguished from other closely related species in the western Atlantic by differences in the setation of thoracic endopod 3, male pleopod 4 and the telson. Heteromysis ebanksae has 2–9 flagellated spiniform setae on male pleopod 4, 6–10 spinules along the anterior half of the telsonic cleft, and each apical lobe of the telson has a pair of spiniform setae, the outer 1.2 times longer than the inner. A diagnostic table separating the new species from H. actinae Clarke, 1955, H. bermudensis G. O. Sars, 1885 and H. floridensis Brattegard, 1969 is presented.

Brain architecture in the terrestrial hermit crab Coenobita clypeatus(Anomura, Coenobitidae), a crustacean with a good aerial sense of smell

BackgroundDuring the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura) are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of Coenobita clypeatus (Herbst, 1791; Anomura, Coenobitidae), a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase.ResultsThe primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that C. clypeatus has visual and mechanosensory skills that are comparable to those of marine Crustacea.ConclusionIn parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of C. clypeatus. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda.

Digestive Endo-Proteases from the Midgut Glands of the Indian White Shrimp, &lt;i&gt;Penaeus Indicus&lt;/i&gt; (Decapoda: Penaeidae) from Kenya

In order to provide information on the digestive capacity of marine crustacea of mariculture potential in Kenya with a view to aiding the development of suitable feeds to support the industry, a biochemical survey was made of enzymes of extracellular digestion in the Indian White shrimp, Penaeus indicus. Results showed midgut gland endo-proteases in wild adult shrimp from the Kenya coast to have optima between pH 7.2 and 8.5 (Trypsin pH 7.5-8.0, Chymotrypsin pH 7.2-7.8, Elastase pH 6.8-8.5) with maximum specific activities of 101-408, 37-516, 70-90 Units mg protein-1 min-1 for trypsin, chymotrypsin and elastase respectively. There was no pepsin. The North Sea Norway lobster, Nephrops norvegicus, was investigated to a lesser extent and found to have much lower trypsin activity than the shrimp and no chymotrypsin. In addition to the cited serine endo-proteases, significant activity in the shrimp was thought to originate from non-serine proteases. This situation may differ from other shrimps in which serine endo-protease activity, especially trypsin, is dominant. Diphenylcarbamyl chloride (DPCC) and 2-Nitro-4-Carboxyphenyl N,N-Diphenylcarbamate (NCDC) inhibited chymotrypsin but not trypsin, Soybean Trypsin Inhibitor (SBTI), Bowman-Birk Chymotrypsin-Trypsin Inhibitor (BBSTCI), N-Tosyl-L-Phenylalanine Chloromethyl Ketone (TPCK), 4-(2-Aminoethyl)-Benzenesulfonylfluoride Hydrochloride (AEBSF) and N-Tosyl-LLysine Chloromethyl Ketone/1-Chloro-3-Tosylamido-7-Amino-L-2-Heptanone Hydrochloride (TLCK) inhibited both, while Phenyl Methanesulfonyl Fluoride/ Phenylmethyl Sulfonyl Fluoride/ &#945;-Toluenesulfonyl Fluoride (PMSF) and Ovomucoid Trypsin Inhibitor (Ovomucoid/OTI) precipitated shrimp homogenate. The effect of the former was inferred from the action of AEBSF which together with TLCK inhibited shrimp trypsin more than chymotrypsin. In contrast, TPCK inhibited shrimp chymotrypsin more than trypsin. These results indicate that relying on imported commercial feeds, usually developed for other species or strains of farmed shrimp in other parts of the world, may not only be too uneconomical but may not provide adequate nutrition to local animals if not efficiently digested. There is, therefore, greater need and urgency to establish detailed enzymic profiles and digestive capacities of locally cultured fin and shellfish. Such studies should parallel those prospecting for suitable feed ingredients while developing local capacity for feed technology.br> West Indian Ocean Journal of Marine Science Vol. 4 (1) 2005: pp. 109-121

Symbiosis

Symbiosis

Seasonal thermal tolerance in marine Crustacea

Seasonal values of the critical thermal maximum (CTMax) of eight species of adult marine Crustacea from temperate latitudes were measured and found to range between 20 and 34 °C. The extent to which CTMax was dependent on acclimatization varied with species but for most of the species studied, summer-captured animals had significantly higher CTMax values than winter-captured animals. Heat shock resulted in an increase in thermotolerance in most species in winter-captured animals, but a different pattern was found for summer-captured animals. Then, only Cancer pagurus and Pagurus bernhardus showed a positive increment of CTMax on heat shock. Test for Serial Independence analysis indicated no significant phylogenetic autocorrelation between CTMax values in winter or summer-captured animals. Temperature measurements taken by remote data loggers in the intertidal zone of the North-East coast of England are reported. These suggest that several species, whose distribution extends into the intertidal zone, may experience temperatures close to their CTMax in summer.

A review of the parasitic dinoflagellates Hematodinium species and Hematodinium-like infections in marine crustaceans

Parasitic dinoflagellates in the genus Hematodinium are important parasites of marine Crustacea. Outbreaks of these parasites have damaged commercial stocks of Norway lobster Nephrops norvegicus, snow crab Chionoecetes opilio, Tanner crab C. bairdi, American blue crab Callinectes sapidus, and velvet swimming crab Necora puber. Species of Hematodinium can reach high enough levels to regulate their host populations, but mortalities are also centred on the unfished juveniles and females, hosts not normally sampled by fisheries; hence impacts are often underreported. Seasonal prevalences of up to 85 % occur annually in many host populations; in effect, these parasites form cryptic blooms in the water column with crabs and other crustaceans at risk of disease. We review the biology and ecology of Hematodinium spp. infections in crustaceans. Included is a comparison of the different infections, a synthesis of what is known, and an attempt to highlight fruitful areas for continued research.

The marine Crustacea Decapoda of Sicily (central Mediterranean Sea): A checklist with remarks on their distribution

A checklist of the Crustacea Decapoda of Sicily, based on previously published records and on original data, is presented. The Sicilian waters were divided into three sectors to account for the different habitats present along the northern and western (sector A), eastern (B) and southern (C) coasts, for the sake of a better interpretation of the species distribution. A total of 186 species was recorded between 0 and 800 m depth, 31 of which are reported here for the first time. Sector A hosted 153 species, B 105 species, and C 117 species. The dissimilarities among the habitats present in the shallow waters of the three sectors accounted for the low co‐occurrence of species: 30 species were common to A and C, 13 to A and B, and 2 to B and C. Seventy‐two species co—occurred in the three sectors, recorded mainly in offshore soft bottoms investigated by trawl surveys. The importance of the aid given by such surveys, as well as by stomach contents analysis, in support of faunistic studies is highlighted. Lastly the affinity of the Mediterranean decapod fauna with that of the northeastern Atlantic is briefly discussed.

Measuring sublethal impacts of pollution on reproductive output of marine Crustacea

Fecundity and fertility in the amphipod Echinogammarus marinus (Leach) were investigated at 2 industrially contaminated sites and compared with data from 2 reference sites. Although some studies have used amphipod fecundity or fertility as biomarkers of environmental perturbation, there has been very little standardisation with regard to the endpoints quantified. Mean brood size, brood size normalised to female weight, and embryos in early and late stages of development have been utilised as measures of amphipod fecundity and fertility. The present study examined the effectiveness of all these measures as biomarkers of pollution. The results suggest that different interpretations can be derived depending on the measure used to express fecundity or fertility. Compared with impacted sites, only reference sites had larger broods normalised to female weight. Separating early- and late-egg developmental stages provided additional information as to whether initial fecundity, or relative fertility, was being affected compared with pooled data (all embryo stages). Both reference sites produced more eggs in early stages of development than impacted sites, but only 1 impacted site had fewer embryo numbers at later stages of development. These results indicate that separating embryo stages in field monitoring or laboratory studies provides more effective indicators of reproductive endpoints, and misinterpretations may result if the loss of eggs and/or embryos from the brood chamber is not taken into consideration.