Amphipods of the genus Phronima are known to make a barrel-shaped house from the gelatinous matrix of pelagic tunicates or siphonophores. Among the seven barrels examined here, one barrel of Phronima curvipes was supposed to be made from a swimming bell of a siphonophore based on its morphology, while the other six barrels made by P. sedentaria were immunochemically and/or morphologically identified as tunicates (i.e. Thetys vagina, other salps and pyrosomas). Histological observation showed that the phronimids had completely eaten the animal tissues other than the gelatinous matrix (i.e. tunic or mesoglea). Tunic cells were found in the tunicate barrel and some were probably tunic phagocytes that appeared to be alive and functional. In the tunicate barrels, cuticular layers of the tunic were found on both the outer and inner side of the barrel wall. Tunic cuticle would be regenerated on the inner side after the epidermis was grazed by the phronimids. The cuticular layers would protect the tunic matrix from the invasion of microorganisms. In the barrel supposed to originate from Thetys vagina, there are minute protrusions on the tunic cuticle as found in the intact tunic of this species. In the barrel from a siphonophore, neither cells nor cuticle regeneration were found. No bacteria were observed in the barrel, suggesting that the barrel has some antibiotic system.

discards represent a significant percentage of the total catches (up to 35%) in the north of spain trawl fishery. in the cantabrian sea (southern area of the bay of biscay), the estimated average total annual catch of small-spotted catshark (scyliorhinus canicula) is approximately 1500 tn, from which 80% is discarded. several experiments have been carried out in order to estimate the survival-rate of the small-spotted catshark caught by commercial trawlers in this area. the estimate of mean survival-rate from tagging surveys was 90% while from commercial trawlers it was 78%. several factors potentially influencing the survival-rate (sex, length, maximum depth fished, sorting time and trawl duration) were examined. no significant differences in survival-rates were found between males and females, and no strong relationships between survival-rate and depth fished, sorting time or trawl duration were evident. in commercial trawlers survival-rate was not dependent on the fish length.

This study was carried out to determine the amphipod fauna in Mar Piccolo, Mar Grande and the Gulf of Taranto. Material in this study was obtained from 96 stations at different depths (maximum depth: −50 m) using various methods depending on the substrata. A total of 65 species was determined and 25 species are new records in the seas of Taranto. Microdeutopus gryllotalpa, Ericthonius brasiliensis, Monocorophium insidiosum, Elasmopus rapax, Gammarus aequicauda, Gammarus insensibilis, Leucothoe spinicarpa, Lysianassa costae and Pseudoprotella phasma were the dominant species and have been found in all areas considered. The comparison of the data shows that the area examined presents a high difference regarding biocenotic index. The highest number of species was collected in the Gulf with 1944 individuals, belonging to 58 species and 19 families, followed by Mar Grande with 1448 individuals belonging to 36 species and 11 families; finally Mar Piccolo with 698 individuals, 12 species and 6 families, in the First Inlet and 546 individuals, 18 species and 6 families, in the Second Inlet.

Ophelia bicornis sensu lato is a polychaete living in intertidal sandy habitats of Mediterranean and European Atlantic coasts, whose systematics have been strongly debated in the past few decades. In the present work the count of nephridiopores was coupled with genetic analysis carried out with DNA markers (inter simple sequence repeats) for a total of 30 individuals collected at six Italian beaches. Exact test, analysis of molecular variance, non-metric multidimensional scaling and assignment tests clearly separated individuals with five nephridiopore pairs from those with six pairs. This finding validated results of a recent allozyme study in which O. bicornis sensu lato was split into O. bicornis sensu stricto (six nephridiopore pairs) and O. barquii (five nephridiopore pairs). This paper represents a further contribution to the estimation of biodiversity within marine invertebrates.

The two zoeal and the megalopal stages of Petrolisthes robsonae, are described and illustrated from laboratory-reared larvae. Larval features are compared with those previously described for other species of Petrolisthes in the eastern Pacific. Larvae of P. robsonae exhibit similar but not identical features to those seen in other Petrolisthes species. A number of similarities are found with P. zacae while main differences are found with P. granulosus,P. platymerus and P. laevigatus. Differences with these species are related to the setation of maxilla and maxillule and the rows of denticles in carapace spines.

A description of the first known mutualistic interaction between a cnidarian and a pelagic tunicate is presented. Calycopsid anthomedusan polyps, belonging in the genus Bythotiara, were discovered associated with individual zooids of a new doliopsid (Thaliacea: Doliolida: Doliopsidae) collected from the mesopelagic waters of Monterey Bay. One hundred and seventy five polyp-bearing doliopsid colonies have been observed and 43 were collected from 1995 to 2004. Colonies were observed in situ and then brought back to the laboratory and maintained in aquaria. More than 250 individual anthomedusan polyps were removed from positions at the buccal siphon of their doliopsid host zooids and maintained in the laboratory until they released medusae. The morphology and taxonomy of the polyps and medusae are described. A unique tentacle-based asexual reproduction strategy is discussed. The relationship between the doliopsid and the polyp appears to be mutualistic, with the doliolid obtaining both nutrition and protection from the anthomedusan polyps, while the polyps gain access to a mobile, food-rich substrate.

The population biology and reproduction of the hermit crab Clibanarius longitarsus were studied with emphasis on size structure, sex ratio, breeding season and fecundity. Specimens were sampled monthly over a period of one year (January–December 2003) at Costa do Sol mangrove, Maputo Bay, southern Mozambique. A total of 597 individuals was obtained of which 202 were males, 192 non-ovigerous females and 203 ovigerous females. Annual size–frequency distributions were polymodal for males and bimodal for non-ovigerous and ovigerous females, respectively. Sexual dimorphism was recorded by the larger average size attained by males in relation to females. Sex ratio was female-biased during most months of the study. Clibanarius longitarsus showed a higher reproductive activity with two major peaks (March and October). Juvenile recruitment was continuous throughout the study period. Clutch size was positively associated with female size. The high number of ovigerous females as obtained in the present population may evidence a higher reproductive activity displayed by C. longitarsus at Costa do Sol mangrove.

The phenomenon of adoption, i.e. replacement of larvae prematurely liberated from the brood pouch of conspecifics, and kin recognition was examined in three mysid species found commonly in Tasmanian waters: Anisomysis mixta australis, Paramesopodopsis rufa and Tenagomysis tasmaniae. A new method for testing the incidence of adoption using fluoroscein dye, which enables the determination of ‘same stage’ adoptions, is described. Under field and laboratory conditions, all species practised intraspecific adoption into their own brood pouches. Under laboratory conditions the incidence of adoption was higher in T. tasmaniae than it was in the other two species. Tenagomysis tasmaniae also adopted its own young in preference to those of a conspecific. Differences in the incidence of adoption between the three species suggests a higher degree of maternal care in T. tasmaniae than in either A. mixta australis or P. rufa and may be explained by differences in anatomy, habitat conditions and predation pressure.

a total of 67 discopyge tschudii was captured. individuals were sexed, measured and their stomach content analysed. siphon tips of the bivalve amiantis purpurata from each stomach were individually counted, weighed and their length and width measured. the size–frequency distribution of the local population of a. purpurata was surveyed for two years. siphons of a. purpurata were the main food item in 90% of individuals having stomach contents. the clam population was markedly bimodal, with 24 mm and 46 mm mean shell length for the younger and older size-classes, respectively. grazing by d. tschudii on a. purpurata varied with size and sex of the fish. small rays mainly ingested small siphons and large rays large siphons. nipped siphon tips were longer in male than in female rays.

During the 2002 Antarctic Deep-sea Biodiversity (ANDEEP) programme to the Drake Passage, Weddell Sea Basin and South Sandwich Slope and trench, a new deep-water species of orbiniid polychaete was collected: Orbiniella andeepia sp. nov. Orbiniella andeepia appears to be most closely related to O. marionensis but differs in capillary setal structure, the type and number of acicular spines found in each podial lobe. Orbiniella andeepia is only the third deep-water species of Orbiniella to be discovered. It exhibits both a wide depth- and geographic-range within the Antarctic slope and abyssal sediments.

During studies performed on the ecological conditions of Izmir Bay and its biota, a population of Fulvia fragilis was observed to have recently colonized the bay. In this study, some comments are provided on the anatomical, ecological, taxonomical and distributional aspects of the species, which was first encountered during late 2001 in Izmir Bay.

The hermit crab Pagurus brevidactylus (Crustacea: Anomura: Paguridea) from the infralittoral area of Anchieta Island, Ubatuba, was characterized by population structure (size, sex ratio, reproduction and recruitment) and growth. Animals were collected monthly during 1999 by SCUBA diving. A total of 1525 individuals was collected (633 males and 892 females), 695 of them were ovigerous females. Overall sex ratio was 0·7:1 in favour of females. The crabs showed a unimodal distribution with males significantly larger than females. Ovigerous females were collected during all months and in high percentages from 1·0 mm of shield length, demonstrating intense and continuous reproduction. The longevity was approximately 24 months for males and 18 for females, which showed larger growth rate and reached sexual maturity earlier (two months) than males. The low number of males in this population may be due to the longer life span. Moreover, the sexual dimorphism favours males during the intra- and interspecific fights by shell, food, reproduction and territory. Females demonstrated a short life cycle and intense reproduction.

Adapting to the bathypelagic habitat imposes serious challenges for taxa that originate in shallower depths. We describe a new doliolid that has successfully made the transition into deep water. Nine specimens of Pseudusa bostigrinus have been found at depths between 1164 and 1890 m in three distinct regions of the eastern North Pacific. This new thaliacean has exchanged the typical doliolid body plan for one resembling a craspedote hydromedusa. This adaptation allows it to collect sinking particles by simply directing its large buccal opening upward. The development of a hydromedusa-like velum allows it to trap zooplankton prey and to propel itself with considerable force and control. While carnivory is not unknown in tunicates, this is the first report of a carnivorous doliolid. The endostyle of P. bostigrinus is greatly reduced, there are no ciliated bands, and there is no spiral gland; all evidence that mucus feeding filters have been abandoned by this species. Anatomy, diet, behaviour, and habitat distinguish this doliolid from all others described to date.

Two ovigerous females of the processid shrimp Processa macrodactyla were caught in April 1997 at 13 m depth in coastal waters of Rota, Cádiz Bay, south-western Spain (36°36′N 6°18′W). Rearing was terminated after nine zoeal stages, when larvae moulted to the first juvenile instar. Descriptions of the appendages of every instar have been made so as to: (1) compare the larval morphology with that of other previous described known species in the genus Processa (P. canaliculata, P. edulis, P. elegantula, P. modica, P. nouveli); and (2) with those larvae not ascribed to a certain species in order to facilitate the specific identification of unknown collected planktonic larvae. When describing P. macrodactyla some characters remained, with few exceptions, invariable in their setation form ZI to ZIV or ZV, to then change and maintain until the last zoeal stage. This can be due to intermediate moults, with the result that some larvae unite the characters of Stages ZIV and ZV and others those of ZV and ZVI.

Patterns in larval supply and recruitment of the invasive European green crab, Carcinus maenas, were examined at two sites in Nova Scotia, Canada: a typical Atlantic coastal site with high salinity (∼33) and strong tidal signal (Terence Bay); and a microtidal site in the Bras d'Or Lakes, where surface salinity fluctuated from 0 to 23 (Benacadie Pond). Abundance of all life history stages (zoeae, megalopae, juveniles and ovigerous females) was sampled approximately biweekly at each site from June 2001 to June 2002. The reproductive season, based on the presence of ovigerous females, is ∼5 months (June to October) at both sites. Zoeae-I were collected from June to July 2001 and in June 2002 at Terence Bay, and from June to August 2001 at Benacadie Pond. We did not collect later zoeal stages at either site. Megalopae were collected from September to October 2001 at Terence Bay, and from August to September 2001 at Benacadie Pond. Juveniles 1–6 mm carapace width (CW) were present throughout the summer at Terence Bay, and only in autumn at Benacadie. Juveniles 6–12 and 12–27 mm CW were present throughout the summer and autumn at both sites. At Terence Bay, densities of 1–6 and 12–27 mm CW juveniles did not vary among intertidal zones. In contrast, the 6–12 mm CW size-class appeared to move higher in the intertidal through the season, possibly due to effects of predation.

the reproductive biology of the spiny dogfish, squalus acanthias, was investigated throughout a year, in the eastern mediterranean sea. one hundred and eighty specimens were sampled of which 119 were females and 61 males, ranging from 320 to 755 mm and from 350 to 820 mm total length (tl), respectively. the minimum size of mature females was 515 mm and 470 mm tl for mature males (smaller compared with sizes in other studies). gonadosomatic index (gsi) and hepatosomatic index (hsi) were higher during june and august in female dogfish, respectively; in males gsi had a peak in july and hsi showed its highest value in april. a total of 39 gravid females was identified with tl ranging between 570 and 755 mm. only 28 of them were bearing embryos; candled uteri were observed in the 11 other gravid animals. a positive relationship was recorded between maternal length and litter size. ovarian fecundity ranged between 1 and 6 (mean 2.1±1.1); uterine fecundity ranged from 1 to 6 (mean 3.3±1.2). the size of the pups varied from 72 to 220 mm tl and their weight ranged between 1.6–48.5 g (mean 11.7±8.6). the spiny dogfish was compared with fish from other study areas and was found to be smaller in size in the eastern mediterranean sea, reaching maturity at smaller sizes and obtaining lower fecundity than female fish in other areas.

Synisoma albertoi sp. nov. (Isopoda: Valvifera: Idoteidae), is described and illustrated from specimens collected in the Strait of Gibraltar (southern Spain). The new species can be distinguished from all other species of the genus, with the exception of S. bellonae and S. raqueliae, by the fusion of the flagellar articles of the antenna. It is easily distinguishable from both S. bellonae and S. raqueliae by the presence of a tubercle on the cephalon; these three species also differ in the morphology of pleotelson, pereopods and appendix masculina. A key to the known species of Synisoma is provided.

Libidoclaea granaria was collected as part of the by-catch of the Zygochlamys patagonica (Bivalvia: Pectinidae) fishery, between 36° and 39°40′S and at 80 to 128 m depth. Crab densities ranged from 0 to 150 individuals 100 m−2, with a mean of 9·8±20·4 individuals 100 m−2. Mature males and females ranged from 24 to 61 mm, and from 16 to 48 mm, carapace width (CW), respectively. The largest immature female measured 22·5 mm CW. The number of eggs carried by a female ranged from 1200 to 9300. Sponges were the most frequent epizoic organisms, followed by the lepadomorph cirriped Ornatoscalpellum gibberum, Serpulidae and Spirorbidae worms. Since all these organisms were reported on Z. patagonica beds, crabs are camouflaged to match their habitat. Small crabs usually had naked carapaces, indicating a high moult frequency. Larger crabs instead, had epibionts on their carapaces, suggesting a lesser moult frequency. The erosion of carapace spines and the heavy epibiosis of large specimens suggest the existence of a terminal anecdysis.

The bivalvia species of the Dardanelles were investigated at the upper infralittoral zone, by diving and dredge. Various species belonging to 14 families were identified in the Dardanelles. The families are as follows: Mytilidae, Ostreidae, Cardiidae, Pimidae, Solenidae, Pectinidae, Arcidae, Nuculidae, Veneridae, Donacidae, Tellinidae, Anomidae, Scrobiculariidae and Gastrochaenidae.

Methods for assessing the occurrence and recency of mating are important for the management and conservation of exploited brachyuran crabs. Using multiparous females of the snow crab Chionoecetes opilio, we evaluated by experiment the efficacy of three indicators of recent mating: a white deposit in the spermathecae, extended mate-guarding, and fresh grasping marks on the female pereiopods. This was done by contrasting sperm counts between the left and the right spermatheca of females that were exposed to males with the right gonopod ablated, at treatment sex ratios of 20[female]:3[male ] or 50[female]:3[male ]. We expected that sperm reserves would be balanced between the two spermathecae of non-mated females and larger in the right than in the left spermatheca of mated females. Although no mating indicator was infallible, the presence of a white deposit was the most accurate because it maximized the median difference of sperm counts between the two spermathecae for the group of presumably mated females and minimized it for the group of presumably non-mated females. The use of grasping marks overestimated the mating frequency and resulted in the misclassification of a large proportion of females. Extended mate-guarding was a slightly better mating indicator than grasping marks, but it is not practical for field studies. Classification errors associated with each indicator can be explained mostly by female and male behaviours and may vary in magnitude with sociosexual context.