Pagurus Prideaux Research Articles

Spatiotemporal and ecological distribution of megabenthic crustaceans on the shelf-shelf break of Antalya Gulf, the eastern Mediterranean Sea

The spatiotemporal distribution and ecology of the suprabenthic and benthic mega-crustaceans were studied in the shelf-shelf break of Turkish waters of the eastern Mediterranean Sea (Antalya Gulf). Sampling was conducted seasonally in May 2014, August, October, and February 2015 using an otter trawl at depths of 10, 25, 75, 125 and 200 m along three transects. A total of 59 species were identified comprising 53 decapods (Eumalacostraca: Eucarida), 3 isopods (Eumalacostraca: Peracarida), and 3 stomatopods (Hoplocarida). Eighteen of the total identifiable species were invasive, and some of them significantly influenced the crustacean community structure. Parapenaeus longirostris, Pagurus prideaux, Charybdis (Goniohellenus) longicollis and Medorippe lanata were the most common species. Parasquilla ferussaci was reported for the first time in Turkish water of the Levantine Sea. Community structure showed seasonal patterns and differed along the depth gradient of habitat heterogeneity. The megabenthic crustacean assemblage was driven mainly by seafloor depth and was related to the fishing disturbance in the area (fishing/no-fishing zones). Environmental parameters were measured for each sample and tested in relationship to crustacean abundance by multivariate analysis CCA (canonical correspondence analysis). The results revealed significant differences in community structure related to substrate and the fine fraction of the bioseston.

Home selection and regular welcome (and not so much) guests in Iberian Hermit Crabs

Home selection and regular welcome (and not so much) guests in Iberian Hermit Crabs

A novel approach for estimation of the natural mortality of the common whelk, Buccinum undatum (L.) and role of hermit crabs in its shell turnover

Analysis of simultaneously occurring live molluscs and empty shells of the whelk Buccinum undatum indicated similar abundance on the seabed making possible the estimation of recent natural mortality. Nearly all empty shells were occupied by hermit crabs Pagurus bernhardus and most of the remainder by Pagurus prideaux. P. bernhardus is highly selective for robust whelk shells, whereas anemone-protected P. prideaux use a range of smaller and thin-walled shells. Application of age size keys based on age reading of opercula surfaces permitted a tentative estimate of natural mortality of M=1.34 on trap fishing grounds for brown crab in the southwest North Sea (whelks aged 4–7 years) and M=0.85 and M=0.63 for the fishing grounds on the Western Waters (whelks aged 4-7 years and 4-9 years respectively). Estimates of total mortality (Z), based on size-frequencies of live whelks, were Z=1.35 (North Sea) and Z=1.46 and 1.23 (Western Waters, aged 4-7 years and 4-9 years). Estimates of M for the North Sea might be biased by differences in trap selectivity between hermit crabs and live whelks. This is a novel approach that might be developed for whelk fisheries assessment and management, particularly using better age determination techniques.

Modelling climate change effects on benthos: Distributional shifts in the North Sea from 2001 to 2099

In the marine realm, climate change can affect a variety of physico-chemical properties with wide-ranging biological effects, but the knowledge of how climate change affects benthic distributions is limited and mainly restricted to coastal environments. To project the response of benthic species of a shelf sea (North Sea) to the expected climate change, the distributions of 75 marine benthic species were modelled and the spatial changes in distribution were projected for 2099 based on modelled bottom temperature and salinity changes using the IPCC scenario A1B. Mean bottom temperature was projected to increase between 0.15 and 5.4 °C, while mean bottom salinity was projected to moderately increase by 1.7. The spatial changes in species distribution were modelled with Maxent and the direction and extent of these changes were assessed. The results showed a latitudinal northward shift for 64% of the species (maximum 109 km; brittle star Ophiothrix fragilis) and a southward shift for 36% (maximum 101 km; hermit crab Pagurus prideaux and the associated cloak anemone Adamsia carciniopados; 105 km). The relatively low rates of distributional shifts compared to fish or plankton species were probably influenced by the regional topography. The environmental gradients in the central North Sea along the 50 m depth contour might act as a ‘barrier’, possibly resulting in a compression of distribution range and hampering further shifts to the north. For 49 species this resulted in a habitat loss up to 100%, while only 11 species could benefit from the warming in terms of habitat gain. Particularly the benthic communities of the southern North Sea, where the strongest temperature increase was projected, would be strongly affected by the distributional changes, since key species showed northward shifts and high rates of habitat loss, with potential ramifications for the functioning of the ecosystem.

Epibenthic assemblages in the Celtic Sea and associated with the Jones Bank

The epibenthic assemblages in the Celtic Sea are described from the catches from 2m beam trawl surveys undertaken from 2000 to 2009. During this period 154 samples were collected. The most ubiquitous species in the study area were the natantid shrimps Processa spp. and Crangon allmanni, the hermit crabs Pagurus prideaux and Anapagurus laevis, sand star Astropecten irregularis and spotted dragonet Callionymus maculatus. Multivariate community analyses indicated that catches (numbers per tow) were distributed across six assemblages, two of which were predominant in the study area. Most catches were attributed to either a ‘shelf edge assemblage‘, which was widespread in deeper waters (114–423m water depth) or an ‘outer shelf assemblage’ that occurred across much of the Celtic Sea north of 49°N in waters 49–175m deep. The dominant species along the edge of the continental shelf were the hormathid anemome Actinauge richardi, sea spider Pycnogonum littorale (which associated with A. richardi), Devonshire cup coral Caryophyllia smithii and the swimming crab Macropipus tuberculatus. The dominant species in the outer shelf assemblage included P. prideaux, C. allmanni, A. laevis and common starfish Asterias rubens. Stations closer to shore were relatively distinct and catches in this ‘inner shelf assemblage’ were composed primarily of an inshore fauna (e.g. Ophiura ophiura, C. allmanni and Liocarcinus holsatus). Stations in the southern part of the survey grid were also relatively distinct (‘southern Celtic Sea assemblage’), and several large echinoderms (Porania pulvillus, Stichastrella rosea and Anseropoda placenta) dominated at these sites. Three of the deepest stations were also relatively distinct, as were a group of stations in the muddy habitat of the Celtic Deep and comparable grounds elsewhere in the region, where Nucula sulcata and Alpheus glaber were characteristic. Catches on the shallower parts of the Jones Bank (and on another bank in the region) were dominated by the anemone Paraphellia expansa, with off-bank sites comprising a greater number of species. In contrast to beam trawl sampling, baited camera observations on the Jones Bank showed a greater richness of species on the shallower part of the bank, and provided information on the nocturnal feeding behaviour of scavenging isopods.

Resource partitioning amongst five coexisting species of gurnards (Scorpaeniforme: Triglidae): Role of trophic and habitat segregation

Feeding habits and habitat preferences of five related species ( Aspitrigla cuculus, Chelidonichthys lucerna, Chelidonichthys obscurus, Eutrigla gurnardus and Trigla lyra) (Scorpaeniformes: Triglidae) were studied in the southern Bay of Biscay. Specimens were collected during annual bottom trawl surveys carried out every autumn between 1990 and 2008 on soft bottoms of the Galician and Cantabrian Sea continental shelf between 30 and 800 m depth. All species were found to display a different depth distribution, despite co-occurring in many of the hauls (co-occurrence percentage ranged between 4.45 and 34.77%). Although depth was the main variable explaining the triglid distribution, latitude, temperature and sediment type were also important driving factors. Regarding feeding habits all triglids fed mainly on crustaceans, their main prey being Alpheus glaber, Polybius henslowii, Scyllarus arctus, Chlorotocus crassicornis and Pagurus prideaux. However, fish accounted for a considerable proportion of the diet with Gadiculus argenteus, Callionymus spp., and Cepola rubescens being the most common fish prey. Ontogenetic changes in diet were evident in all species but C. obscurus. Dietary overlap, determined by the Schoener Index greatly differed amongst species pairs ranging between 0.10 and 0.63. Considering all ontogenetic groups in the triglid assemblage, either diet or habitat segregation occurred between most of them. This fact suggests that any of these strategies on their own would suffice in order to avoid inter and intra specific competitions. Nevertheless, habitat partitioning occurred mainly at the inter-specific level and trophic segregation at the intra-specific level. A. cuculus and E. gurnardus showed the poorest resource partitioning in the assemblage, possibly as a consequence of the increasing abundance of the population of the first during the last decades.

Prevalence and seasonality of Hematodinium (Alveolata: Syndinea) in a Scottish crustacean community

Abstract Hamilton, K. M., Shaw, P. W., and Morritt, D. 2009. Prevalence and seasonality of Hematodinium (Alveolata: Syndinea) in a Scottish crustacean community. – ICES Journal of Marine Science, 66: 1837–1845. Protist parasites of the genus Hematodinium were detected in seven crustacean species (Cancer pagurus, Carcinus maenas, Liocarcinus depurator, Munida rugosa, Necora puber, Pagurus bernhardus, and Pagurus prideaux) from the Clyde Sea in Scotland. Seasonal screening of different tissues with sensitive molecular probes showed average infection of 3–23%, with prevalence reaching almost 60% in hermit crabs (P. bernhardus) and brachyuran hosts in spring and >30% in C. pagurus and N. puber in autumn. During summer, Hematodinium infections were rare. Hematodinium seemed to be present in all host sizes sampled. The infection was equally distributed between males and females in most host species, except C. maenas, where males seemed to be more susceptible to infection. PCR amplification of the Hematodinium ribosomal RNA gene in crustacean tissue detected the parasite most frequently in muscle, gills, and heart throughout the 2-year sampling period.

Hermit crabs

Hermit crabs

Taxonomic and biological notes on a species of Iphitime (Polychaeta, Eunicida) associated with Pagurus prideaux from western Norway

On the basis of 658 specimens collected over an 11 year period, the symbiotic eunicid polychaete, Iphitime paguri Fage & Legendre, 1934, is redescribed, and its biology in its presumed preferred host, Pagurus prideaux Leach, 1815, is outlined. The main ecological part is based on sampling of Pagurus on five occasions throughout a year in Raunefjorden, southwest of Bergen. Iphitime paguri turned out to have a strong sexual dimorphism, both in outer appearance and in the morphology of the jaws. Both juveniles and mature individuals of both genders are described. The infestation rate of Pagurus prideaux was very high (as opposed to the low reported infestation rate in Pagurus bernhardus, generally regarded as the host of this species) and the symbiotic polychaetes turned out to have a distinct pattern of host utilization in different life stages. Ripe males and females were, at certain times of the year, generally found more or less intertwined in the apex of the gastropod shell inhabited by its host. Small larval stages were found in the same place. Intermediate size groups were found in the gill chamber and in a sulcus on the carapax of the pagurid host.

Amino acid composition of early stages of cephalopods and effect of amino acid dietary treatments on Octopus vulgaris paralarvae

During the present study, we aimed to provide a first look at the amino acid composition of the early stages of cephalopods and follow possible effects of certain dietary treatments. Amino acid profiles of cuttlefish Sepia officinalis, squid Loligo vulgaris and octopus, Octopus vulgaris hatchlings and wild juveniles of L. vulgaris and O. vulgaris were analysed. Cephalopod hatchlings showed high fractions of non-protein nitrogen (NPN), from 25% to 38% of the dry weight. Lysine, leucine and arginine represented half of the total content of essential amino acids (EAA), and glutamate and aspartate represented also nearly half of the non-essential amino acids (NEAA). In O. vulgaris, a general tendency for a decrease in the level of EAA from mature ovary and eggs to hatchlings was observed. Hatchlings after 4 days of fasting lost 28% of their dry weight and the level of EAA and NEAA decreased in both the total content and free forms. Free proline after 2 days of fasting and free tyrosine at 4 days of fasting were not detected. Comparison of the total EAA profiles of preys showed few differences between enriched Artemia nauplii and hatching crab zoeae ( Pagurus prideaux and Maja squinado). The enriched Artemia nauplii EAA profiles showed no differences with the EAA profiles of O. vulgaris paralarvae during first 10 days of culture, except for histidine. Present results confirm the positive capacity for amino acid uptake from seawater by early stages of cephalopods. In the three species analysed, radiolabelled phenylalanine was incorporated in inverse relation to body size. After 10 days of culture, O. vulgaris paralarvae showed a tendency to increase the levels of total and free amino acids in the groups receiving a daily amino acids solution. At 20 days of age, the O. vulgaris cultures that received the amino acids solution had survivals that on average were three times that of the control group. However, the supposed beneficial effects of the amino acids solution remained unclear, as the dry weight of these paralarvae was equal or lower to that of paralarvae from the control group. In wild O. vulgaris juveniles, the percentage of protein and total amino acids increased with the dry weight of the individuals. These juvenile biochemical changes were associated with strong morphometric changes in body proportions after settlement with the development of the muscular, protein-rich arm crown.

Lipid and fatty acid composition of early stages of cephalopods: an approach to their lipid requirements

We report here the main lipid classes and the fatty acid composition from the total lipids of hatchlings of three cephalopod species: Sepia officinalis, Loligo vulgaris and Octopus vulgaris, as well as the lipid composition of two selected crustaceans that have been used previously with success as food resource for rearing cephalopod hatchlings: zoeae of Pagurus prideaux and the mysidacean Acanthomysis longicornis. Additionally, we report the lipid class and fatty acid composition of two cultures of O. vulgaris paralarvae reared with enriched Artemia juveniles, and with enriched Artemia juveniles plus a prepared pelleted diet. From their lipid composition and that of their natural food, it can be deduced that cephalopod paralarvae and juveniles must require a food rich in polyunsaturated fatty acids (PUFA), phospholipids and cholesterol and with a moderate content in neutral lipids. There was a clear influence of the lipid composition of the food on the lipids of cultured octopus paralarvae both at the level of lipid class and fatty acid composition. The cultured octopus paralarvae showed a lower content of PUFA as compared with the newly hatched individuals. Co-feeding techniques based on the use of polar lipid and PUFA enriched Artemia together with palatable pellets seemed to be a possible way to improve paralarval and juvenile cephalopod culture beyond the experimental scale.

Swimming behaviour and food searching in planktonic Octopus vulgaris Cuvier from hatching to settlement

The planktonic life in Mediterranean Octopus vulgaris lasts about 2 months but we know virtually nothing of this phase of its life history, which represents around 10–15% of the estimated life span. Swimming behaviour from hatching to settlement was studied by video-recording techniques, using five groups aged 1, 15, 30, 42 and 60 days, by when they have become benthic. During the planktonic stage, the backwards, squid-like jet swimming was the predominant type of displacement. Strong morphometric changes, basically in arm growth, influence their jetting capacities and probably the settlement process. Feeding behaviour was analyzed using two species of decapod zoeae as prey, Liocarcinus depurator (L.) and Pagurus prideaux Leach; it is that of a visual predator. The forward displacement typically forms part of this predatory behaviour. During the planktonic phase, the presence of prey increases the turning rate and reduces the swimming speed of Octopus vulgaris individuals. Both responses may improve the exploitation of patchy food environments.

Decapod crab zoeae as food for rearing cephalopod paralarvae

A simple method of providing a regular supply of live food for the experimental culture of paralarval cephalopods is described. The primary food source utilized was hatched zoeae of large laboratory populations of the hermit crab, Pagurus prideaux. Zoeal size, swimming behaviour, and distribution in the water column make these zoeae a suitable live prey for rearing early post-hatching planktonic stages of cephalopods and probably other marine zooplanktivores. Ovigerous P. prideaux females were collected from the sea throughout the year at depths between 10 and 90 m in the NW Mediterranean and maintained at densities of up to 500 specimens · m −2. One month after spawning in aquaria, 38% of the females of P. prideaux started to incubate a second clutch of eggs. Other decapod crustacean species, such as Liocarcinus depurator and Dardanus arrosor, were maintained to use their zoeae as a food source for cephalopod paralarvae. P. prideaux zoeae were used as the sole or main food resource for rearing Loligo vulgaris and Octopus vulgaris, during the first 2 months of life. First feeding and initial growth in L. vulgaris and O. vulgaris paralarvae can be successfully stimulated using decapod zoeae with a total length equivalent to 50–100% of the cephalopod's mantle length.

Development of epipods and gills in some pagurids and brachyurans

The development of gills is described in zoea and megalopa stages of the following 16 species of decapods, and the patterns of gill development are discussed in terms of phylogenetic relationships of the larvae: Pagurus prideaux Leach, Pagurus bernhardus (Linnaeus), Inachus dorsettensis (Pennant), Hyas araneus (Linnaeus), Eurynome aspera (Pennant), Pisa armata (Latreille), Carcinus maenus (Linnaeus), Liocarcinus corrugatus (Pennant), Liocarcinus holsatus (Fabricius), Pilumnus hirtellus (Linnaeus), Monodaeus couchi (Couch), Pinnotheres pinnotheres (Linnaeus), Pinnotheres pisum (Linnaeus), Pinnaxodes mutuensis Sakai, Pinnixa rathbuni Sakai and Pinnixa (?)chaetopterana Stimpson. The gills of most of the species investigated migrate during development, not only dorsally but, in some cases, also posteriorly. The Pinnotheridae provide the only known example in which rudiments of ‘lost’ gills appear within larval stages only to disappear by the first crab stage.