Pinna nobilis is an endemic Mediterranean species of high economic and cultural importance. Nowadays, it is under strict protection as a dramatic decline in its populations has been recognized, assigned to the combined effect of fisheries and habitat degradation. This study attempts to evaluate, by non-destructive sampling, the current status of P. nobilis populations in the south Aegean Sea (Dodecanese island complex), where they have been affected for centuries by practically uncontrolled harvesting. Population density and total length of individuals was estimated by diving along strip transects at six islands. Two stations were randomly selected per island, and two depth zones were surveyed per station. Additionally, temporal sampling was carried out at Astypalaia Island from March 2004 to June 2006, to assess relevant trends in density of individuals and size structure of the population. In total 1372 P. nobilis individuals were measured in situ to estimate maximum shell length. The studied populations showed increased density in the shallower depth zone and sheltered sites; small-scale environmental regimes are proposed as shaping factors of P. nobilis distribution. Increased density was also detected during the cold period of the year, probably related to recruitment success. In the lower depth zone the P. nobilis population consisted of larger individuals. A significant decrease in size was detected temporally as mean length was smaller in December 2004; in the same month the presence of small-sized juveniles was depicted in a left-shift in size–frequency distribution. These observations are probably related to the reproductive biology of the species.

The trophic spectrum of both Eucinostomus entomelas and Micropogonias megalops, the two most abundant fish species in Laguna Las Guásimas, Sonora, México is described in our study. A total of 21 types of prey were identified belonging to seven taxonomic groups (Crustacea, Mollusca, Annelida, Rhodophyta, Copepoda, Echinodermata and Chordata) to analyse the feeding spectra and diet breadth. The preferred prey items of Eucinostomus entomelas (Dark-spot mojarra) were Polichaeta (index of relative importance = 46.7%), followed by bivalves (36.6%), and Luidia columbia (5.6%), while those of Micropogonias megalops (Bigeye croaker) were Portunidae (22.8%) followed by Gammaridae (20.55%) and Crustacea (18.37%). The trophic spectrum for male E. entomela was composed of Bivalvia and Polychaeta. Both predators showed low values in diet breadth (E. entomelas (Levin's index Bi = 0.14) and M. megalops (Levins's index Bi = 0.43)). The low trophic overlap (Cλ = 0.14) between predators suggests that both fish are not competing with each other for food resources in Laguna Las Guásimas.

Aruba is one of the most densely populated islands in the Caribbean. However, very little is known about its cetaceans. In 2010 and 2011, a total of 19721 km (1686 h) boat-based surveys over nearshore transects resulted in 117 positively-identified sightings comprising eight species. New records are also added for one of three previously-documented species. Five additional species were documented from strandings or reports by others. This brings the total number of cetacean species identified in Aruban waters to 16, of which nine are authenticated here for the first time. Atlantic spotted dolphin (Stenella frontalis (N = 59) and bottlenose dolphin (Tursiops truncatus) (N = 33) were the most frequently observed species, with sightings of both year-round, followed by spinner dolphin (S. longirostris) and false killer whale (Pseudorca crassidens). Additional species recorded are pantropical spotted dolphin (S. attenuata), striped dolphin (S. coeruleoalba), common dolphin (Delphinus capensis), rough-toothed dolphin (Steno bredanensis), short-finned pilot whale (Globicephala macrorhynchus), killer whale (Orcinus orca), Risso's dolphin (Grampus griseus), humpback whale (Megaptera novaeangliae), Bryde's/Eden's whale (Balaenoptera brydei/edeni), sperm whale (Physeter macrocephalus) and an unidentified beaked whale (Mesoplodon sp.). All cetaceans were sighted within 22 km of the coast in relatively shallow waters. Sighting rate was low (0.69 cetacean sightings per 100 km). Sightings of calves and neonates indicate that Aruba may be a nursing or breeding area for some species. The presence of several species of cetaceans in Aruba's coastal waters year-round indicates that status and threat assessments are needed to protect them.

Sea food is very rich in lipids. The brown shrimp, Crangon crangon is a most popular and very valuable taxon in the White Sea, in the Mediterranean and in the Black Seas. The aim of this study was to determine the seasonal variations of lipids in C. crangon muscle tissue using gas chromatography–mass spectrometry. The lipids were separated into groups: neutral lipids (triacylglycerols, free fatty acids, sterols) and polar lipids (phospholipids), by high performance liquid chromatography with a laser light-scattering detector. Fatty acids were identified using the GC-MS technique. The mainly fatty acids were 16:0, 18:0 (saturated FAs), 16:1, 18:1 (monounsaturated FAs), 20:4 (ARA), 20:5 (EPA) and 22:6 (DHA). The largest amounts of fatty acids in the muscle were observed in spring; these were the result of collecting food after winter and before reproduction. The muscle lipid content was 32.2 ± 1.8 mg g−1. The summer was the poorest season and the lipid value was 7.7 ±0.4 mg g−1. The levels of muscle neutral lipids (NL) oscillated between 80% (autumn) and 90% (spring). The temperature and salinity has a significant influence on content and profile of fatty acids. This work will help to understand the biology, the seasonal variation in lipid mass, lipid classes content and fatty acids profile in the abdominal muscle of C. crangon.

Two new species of chemosymbiotic bivalves are described from a poorly localized site in the Hatton–Rockall Basin at 1187–1200 m. The new species Isorropodon mackayi sp. nov. is compared with others of the genus from the North and South Atlantic. A novel anatomical structure, suggested to be a secondary gill, is described. The second bivalve Thyasira scotiae sp. nov. is compared with other species known to inhabit cold seeps in the Atlantic and most resembles Thyasira sarsi. Other than the minor morphological differences, the bathyal range and presence of commensal polychaetes, Antonbrunnia, never reported in T. sarsi support the erection of a new species. In the North Atlantic Isorropodon species and the larger thyasirids, with the exception of T. sarsi, are typically found at hydrocarbon seeps associated with pockmarks and mud volcanoes. If correct, then this is the first indication of active sulphidic seepage in the Hatton–Rockall Basin.

The goal of the present study was to assess the temporal and spatial distribution of L. schmitti in three bays of the northern coast of the State of São Paulo, Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV), over a period of two years (1998 and 1999). Abiotic factors were monitored to test their influence on the distribution of the species through redundancy analysis. The shrimp were captured using a commercial fishing boat equipped with double-rig trawling nets at six sampling points. A total of 5658 individuals were collected during the study (4437 and 1221 in the first and second years, respectively). The number of individuals differed between years, bays, seasons and sampling locations. The highest number of L. schmitti was collected in MV (N = 2747), followed by UBM (N = 1649) and UBA (N = 1262). Shrimp abundance correlated positively with organic matter content, salinity and temperature, with the highest number of individuals collected from sites with intermediate levels of organic content (4 and 6%) and increasing when the sediment had a higher proportion of fine and very fine sand + clay. Abundance was also associated negatively with rainfall, given that the analysed population showed a seasonal pattern, with an increase in capture rate in those months following the rainy season. Average rainfall was 222.47 ± 138.68 mm, with a maximum of 538 mm and a minimum of 22.4 mm. The results obtained in this study suggest that, in the region of Ubatuba, temperature, salinity, organic content and rainfall modulate the distribution of these animals.

A new species of the family Tritoniidae is described from the tropical South Atlantic Ocean. The animal was found off north-east Brazil. Tritonia khaleesi sp. nov. is up to 12 mm long, with a slender white body, of which the notum is covered with one broad white band extending from between the eyes and veil to the tail; veil with 4 velar appendages; retractable white rhinophores; rhinophoral sheath with fleshy extension; seven pairs of branchial plumes; the anus is located between the 3rd and 4th gills on the right side, and the genital opening is under the 2nd gill. Internally, T. khaleesi sp. nov. is distinguished from other tritoniids by jaws with 10–14 rows of denticles on the inner lips, absence of stomach plates and the radular formula 32 × 2–5.1.1.1.2–5 teeth. Tritonia khaleesi sp. nov. is the only Tritonia that possesses a unicuspid rachidian tooth as an adult.

Genetic variation of mussels Mytilus galloprovincialis in central–eastern Mediterranean Sea is investigated in this study. A total of 550 individuals sampled from two cultured and 11 wild populations from Italy, Croatia, Greece and Turkey were genotyped at 10 microsatellite loci. Significant deviations from Hardy–Weinberg expectations were observed in more than 75% of the tests performed. All populations showed extensive heterozygote deficits, which remained at significant levels even after correction for null alleles, providing evidence that null alleles were only partly responsible for deviations from Hardy–Weinberg equilibrium in these molluscs. Moreover, null alleles seem to have limited influence on the population genetic differentiation. Similar levels of multi-locus heterozygosity and allelic richness were observed in all populations, cultured and wild, implying the sustainability of the exploited populations. Lack of isolation by distance and markedly low genetic differentiation between the nine Greek sampling sites (shoreline >1000 km) was revealed by Mantel tests, FST values, exact tests and analyses of molecular variance, indicating that mussels from these regions are either at or close to panmixia. Similarly, patterns of genetic homogeneity were also found between the two Italian samples, whereas the observed genetic differentiation of the populations from Turkey and Croatia probably reflects the specific topographic and oceanographic conditions of these regions.

Reproductive aspects of the intensively traded ornamental shrimp Lysmata boggessi were examined. Abundance, reproductive biology (fecundity, reproductive output and egg size) and population structure (frequency distribution, size at sex phase change and sex phase ratio) were examined at three different fishing grounds off south and west-central Florida between May 2011 and February 2012. Fishery-dependent densities of L. boggessi varied between 2.51 ± 1.39 and 13.05 ± 9.30 shrimps per 1000 m2 at two different localities. The proportion of brooding shrimp varied considerably at one locality during two different dates, suggesting reproductive seasonality. Reproductive output increased linearly with shrimp body weight (SBW) at one locality (May 2011), but scaled negatively with SBW at a second locality (January–February 2012). Lastly, no correlation between embryo size and shrimp carapace length (CL) was recorded at one locality (May 2011), but a slight negative correlation between embryo size and CL was found at the second locality (January–February 2012). Lysmata boggessi might be experiencing trade-offs between different reproductive parameters driven by environmental, probably seasonal, conditions during the year. All of this information needs to be considered in assessing shrimp stocks and establishing a sustainable management plan.

This paper represents the first quantitative assessment of the distribution and abundance of bottlenose dolphins (Tursiops truncatus) inhabiting the waters around Lampedusa Island, Italy. Eleven years of photo-identification data, collected from 1996 to 2006 by three different research groups, were brought together, reviewed and analysed to fulfil the following objectives: (i) to obtain baseline information on the abundance and residency of the local bottlenose dolphin putative population; (ii) to review the current Marine Protected Area (MPA) boundaries, especially those referred to waters around Lampedusa Island, with a view to establish a new Special Area of Conservation (SAC); and (iii) to explore the potential and limits of analysing heterogeneous datasets to improve future data collection methods. The most resident dolphins were regularly observed in six specific areas around Lampedusa Island. From a total of 148 photo-identified bottlenose dolphins, 102 were classified as well-marked. The capture histories and the distribution of sightings clearly show a number of dolphins regularly use the study area. Best estimates for the first period within the ‘core study area’ were obtained for 1998 data. The 2005 estimate was significantly larger than the 1998 estimates (z = 2.160; P < 0.05) compared to that of 1998. Implications of our results for the current MPA, for transboundary conservation initiative involving Italy, Malta and Tunisia and for directing future research within and outside the MPA are fully discussed.

Food partitioning between species is a common strategy for avoiding resource competition which allows the coexistence of two or more species in the same place. In order to evaluate the feeding of four species of batoids regularly caught by artisanal fisheries in southern Brazil, the present study aimed to analyse and compare the diet of the four batoid species. The Chola guitarfish, Rhinobatos percellens, had a specialized diet, consisting predominantly of blue crabs Callinectes sp., followed by teleost fish. The Lesser guitarfish Zapteryx brevirostris also had a very specialized diet, consuming mainly on Polychaeta, followed by Caridea shrimp. The Cownose ray, Rhinoptera bonasus, fed mainly on Ophiuroidea, followed by Gastropoda and Bivalvia. Finally, the Rio skate Rioraja agassizi, fed on teleost fish, Gammaridae, Caridea shrimp and Dendrobranchiata shrimp. An analysis of similarity showed significant differences among species in their diet. The trophic levels of the batoids in this study are <4.0, placing them in intermediate trophic levels. The analysis of the diets indicates that feeding differs substantially among the four species, suggesting a partitioning of food resources available in the environment.

Egg clutch brooding and larval release behaviour are common among decapods and involve pheromone communication between the developing embryos and the brooding female. We tested caridean shrimps to determine whether their behaviour was similar to other decapods. In tests with aqueous extracts of crushed eggs and peptide pheromone mimic shrimps responded similarly to brachyurans and lobsters. The elongate body form of shrimps enabled us to focally stimulate body locations with the goal of determining the location of pheromone receptors. The receptors for the pheromones are likely located on the bases of the walking legs or on the gills, not on the pleopods, first walking legs, antennae or antennules. Shrimps are another example of organisms that use peptides generated by trypsin-like serine proteases as pheromones and signal molecules.

The morphology of the first zoea of Gnathophyllum elegans is described from laboratory-reared material for the first time and analysed in detail with light and scanning electron microscopy. For systematic reasons, morphological characteristics in G. elegans are compared with those in Gnathophyllum americanum, Periclimenes amethysteus, a representative of the subfamily Pontoniinae and the closely related Hymenocera picta (Decapoda: Caridea: Hymenoceridae). We observed differences in the morphology of both Gnathophyllum-larvae, such as the number and arrangement of certain setae. Thus, larvae of the two Gnathophyllum species can be readily distinguished from each other. Further differential diagnosis with P. amethysteus confirms a high similarity between Gnathophyllum-larvae and larvae in the subfamily Pontoniinae, as already mentioned in earlier publications. The systematic relationships of the Gnathophyllidae, Hymenoceridae and Pontoniinae are discussed based on zoeal characters.

The reproductive biology of the pelagic thresher shark Alopias pelagicus, was analysed based on 241 individuals (101 males and 140 females). Samples were collected from April 2005 to February 2006, from the artisanal fishery in Manta, Ecuador. Males ranged from 68 to 183 cm precaudal length (PL); females ranged from 70 to 180 cm PL. In embryos, sexual proportion was 1F:1M; while in adults the proportion was 1.4F:1M, which suggests sexual segregation in maturing individuals. We showed differences in the development of reproductive structures according to the reproductive condition, and in males the size at maturity occurs at 144.3 cm PL and in females at 151.4 cm PL. We recorded 33 pregnant females that presented one embryo in each uterus in different developmental stages. The results of this study provide information on reproduction of the species that will help to establish an appropriate fisheries management.

An investigation of ectoparasites of skates caught off the coast of Lesvos Island, north-eastern Aegean, Greece was performed from May 2010 to February 2012. One parasite, identified as the marine leech Pontobdella muricata, was found on the skin of 0.43% of Raja clavata and 3.6% of Dasyatis pastinaca specimens examined during the investigation period. This is the first record of D. pastinaca as being a host to P. muricata. Macroscopic and microscopic observation of the lesions caused by the parasitism, revealed haemorrhages and swelling of the skin of R. clavata, a milder inflammation of the skin of D. pastinaca, congestion, necrosis and liquefaction of the skin at the site of leech attachment and a lesion with disappearance of upper skin layers after the detachment of the leech.

The Ostreidae are well known for their high intra-specific variation, which makes identification problematic. The present paper aims to provide a morpho-anatomical and taxonomic review of the Brazilian species of Crassostrea, as well as some congeneric species from other relevant areas. The Brazilian species are Crassostrea mangle sp.nov. and Crassostrea brasiliana. The exotic species Crassostrea gigas, cultivated in the southern region of the country, is also included in this study. Additional species are: Crassostrea virginica, from the Atlantic coast of the USA, the type species, and Crassostrea rhizophorae, a south-eastern Caribbean species that is supposed to occur in Brazil, but is here understood as a different entity endemic to that region. Taking into account their economic importance, the differentiation between these species is critical, and is essential for a better planning of production and preservation strategies. We point out the differences in almost all structures amongst these species, which are formally redescribed herein. The occurrence of the African species Crassostrea gasar in Brazil is established as false. The voucher specimens of previous studies responsible for this assumption were examined, evidencing a misidentification for Crassostrea brasiliana from an estuarine environment. The geographical distribution of the studied species is recognized as follows: Crassostrea rhizophorae in the south-east Caribbean Sea; Crassostrea mangle sp. nov. from Pará to the Santa Catarina, only in mangroves; Crassostrea brasiliana from Paraíba to Santa Catarina, both in rocky shores and mangroves; Crassostrea virginica ranges from the Atlantic coast of Canada to the Caribbean; and Crassostrea gigas originates from the Indo-Pacific, but has been introduced in southern Brazil. This paper also deals with conchological aspects of the endemic species Crassostrea praia, from south Lagoa dos Patos, Rio Grande do Sul; after a more detailed definition, and considering the deleterious effects of the nearby port and construction sites, it can be classified as an endangered species.

The waters off north-west Scotland are known to provide important habitat for the harbour porpoise (Phocoena phocoena) and the minke whale (Balaenoptera acutorostrata). Between October 2008 and April 2011, systematic land-based surveys were carried out to assess the seasonal occurrence, group size and group behaviours of both species in a study area located off Melvaig, near Gairloch. Data were collected on 47 separate days, with a total of 4543 minutes of survey effort (in sea states ≤3) recorded during the spring months and 8204 minutes of effort during the autumn. A total of 189 sightings of marine fauna were recorded, comprising 126 cetacean sightings, 50 seal sightings and 13 sightings of basking sharks (Cetorhinus maximus). Six species of cetacean were identified, with most sightings comprising harbour porpoise (N = 72) or minke whale (N = 38). Harbour porpoise abundance was higher in autumn than in spring and there was a variation between years in numbers of minke whales sighted. In porpoises, sea state and cloud cover both influenced sightings and increasing sea state influenced survey area. Foraging behaviour was exhibited in 13% of harbour porpoise sightings and 34% of minke whale sightings. Results demonstrate a regular occurrence of harbour porpoises and minke whales in nearshore waters off Gairloch. Densities are comparable to boat surveys in the region and so support the use of land-based watches as a potential longer-term monitoring method for these species in coastal waters. Given the regular use of this area by these two European Protected Species, as well as the occurrence of a range of human activities potentially affecting them in the region, it may be appropriate to consider protecting this area for their conservation.

Preliminary molecular data obtained from one mitochondrial (COI) and one nuclear marker (H3) from the available species of the genus Okenia have revealed a new cryptic species of this genus. The new species (Okenia harastii sp. nov.), from New South Wales (NSW) eastern Australia, has a light brown body with scattered dark brown and white spots of different sizes, and six pairs of translucent mantle processes. Okenia harastii sp. nov. is compared with other Okenia species from NSW and with other morphologically similar species.