Alterations of membrane lipid composition (cholesterol, phospholipids and their fatty acids) in response to various temperature changes were studied in blue mussels Mytilus edulis L. from the White Sea. Lipid composition changes after acute temperature stress, especially a temperature drop, included a significant reduction of the membrane phospholipid content directly (1 h) after return to the initial temperature, which was presumably a consequence of a non-specific stress reaction in the mussels. A longer recovery period (24 h) as well as long-term temperature acclimation (14 days) induced changes in gill fatty acid composition (for instance, a rise in phospholipid unsaturated fatty acids under low temperature impact), indicating ‘homeoviscous adaptation’ to maintain the membranes in response to temperature fluctuations. Moreover, the gill cholesterol level in mussels varied especially at long-term temperature exposure.

Specimens collected in or near Pensacola Bay, Florida matching the descriptions of Luidia lawrencei and Luidia clathrata (the congener from which L. lawrencei was recently split) were compared to determine whether their recent taxonomic separation is supported by differences in sediment preference, salinity tolerance and COX-1 mtDNA sequences. Luidia clathrata has a preference for smaller grain sizes, while no statistically significant preference was found for Luidia lawrencei, and no significant difference was found between the species. Luidia clathrata is more tolerant of lower salinity based on the righting response than Luidia lawrencei, especially at salinities lower than 25 g kg−1. The COX-1 comparison returned over 99% homology among individuals of the two species. While sediment preference and salinity tolerance results indicate differences in response to habitat dissimilarities, the COX-1 genetic result is strong evidence against the recently proposed separation of the species. In light of the COX-1 result, we interpret the sediment and salinity results as long-term acclimation responses.

In July–August 2004, the Mid-Atlantic Ridge Ecosystems (MAR-Eco) expedition collected Demospongiae (Porifera) from the Northern Mid-Atlantic Ridge (MAR) north of the Azores, between 41°N and 61°N. Demosponges were found at 10 stations, at depths ranging from 753 to 3046 m. Twenty-two species were identified: 17 Tetractinellida, one Polymastiida, one Suberitida, two Poecilosclerida and one Dendroceratida. The study of this material is an opportunity to revise the taxonomy and the North Atlantic distribution of each of these deep-sea species. Some species are particularly rare and poorly known (Tetilla longipilis, Tetilla sandalina, Craniella azorica, Polymastia corticata) and two are new to science: Forcepia (Forcepia) toxafera sp. nov. and Iotroata paravaridens sp. nov. This study suggests that the MAR is not a longitudinal barrier for the dispersal of deep-sea demosponges while on the contrary, the Charlie-Gibbs Fracture Zone (CGFZ) may be a latitudinal border for the dispersal of deep-sea demosponges, due to great depths and currents.

Shipworms (teredinids) are highly specialized marine bivalves that consume terrestrially derived wood. Changes in environmental variables may result in shipworms spreading into the Baltic Sea – which would have devastating consequences for maritime cultural heritage and submerged wooden structures. We investigated the distribution and abundance of the shipworms Teredo navalis and Psiloteredo megotara along the Swedish coast in 2006–2008, and compared our findings with data collected at partly the same locations in 1971–1973. Wooden test panels were submerged in near-surface waters at 18 harbours. The presence of shipworms was determined by X-ray radiography of each panel. Sea surface temperature and salinity data were analysed to investigate whether any changes in distribution were correlated to changes in environmental variables. We found that past and present distributions of T. navalis were similar – indicating that no range expansion of shipworms into the Baltic Sea has taken place the last 35 years. The abundance of T. navalis was similar between decades at all investigated sites except two (Arild and Barsebäckshamn), where abundances were higher in 2006–2008. The abundance of T. navalis varied along the coast and was positively correlated to mean sea surface salinity, but not to mean sea surface temperature (2006–2008 data). The distribution and abundance of P. megotara were similar during the two study periods with only single observations at a few sites. In conclusion, we found no evidence of range expansion of shipworms along the Swedish coast.

Coastal lagoons are highly variable environments that may act as hotspots of genetic diversity as a consequence of their ecological role as nursery habitats of marine species with both ecological and fisheries importance. The edible cockle (Cerastoderma edule) is a commercially important shellfish resource inhabiting coastal lagoons in Europe and their fisheries management urgently needs genetic studies to design appropriate strategies to promote the recovery of exploited populations. The aim of this study was to assess the C. edule genetic diversity and population structure at a small geographic scale, inside Ria Formosa coastal lagoon (southern Portugal) using mitochondrial cytochrome oxidase I sequences in six locations. Outcomes pointed to a common pattern of high haplotype diversity and non-significant genetic structuring inside the Ria Formosa lagoon. A high level of gene flow was detected between all localities and the presence of a single stock from a genetic point of view may be considered for fisheries management purposes. The existence of a high number of haplotypes and high values of haplotype diversity of C. edule in Ria Formosa lagoon could be consistent with the hypothesis that higher genetic diversity is expected in populations occurring in coastal lagoons, suggesting that lagoons could increase standing genetic variation and an adaptive potential of lagoon populations as an ecological response to a highly variable environment.

Despite being one of the most abundant and highly exploited species in the Mexican Pacific Ocean, information on the biology of the silky shark, Carcharhinus falciformis is limited. The objective of the present study was to describe the reproductive biology of this species, based on 262 sharks (117 females and 145 males) caught from September 2004 to May 2006 in the Gulf of Tehuantepec, Mexico. The size of females ranged from 70 to 229 cm total length (TL); males measured from 69 to 220 cm TL. Female reproductive organ measurements showed that between 175 and 190 cm TL there was an increase in oviducal gland width (19–45 mm), as well as in uterus size (20–220 mm width). Mature males over 180 cm had calcified claspers, well-developed testes (184–282 mm) and presence of sperm in the seminal vesicles. The estimated length of males at first maturity was 180 cm, and that of females was 190 cm. Ovarian fecundity varied from 4 to 11 oocytes, and uterine fecundity varied from 2 to 14 embryos. We infer that mating occurs between May and June. We did not find sperm storage in the oviducal glands. Birth size was observed to be between 60 and 69 cm TL. No defined gestation period was observed.

T-bar anchor tags and Petersen discs were used during a preliminary mark–recapture experiment in the wild on 268 Octopus vulgaris. Discs, despite causing some injuries, were characterized by a quicker healing (within 5 days) and a higher retention rate than T-bar tags (about 97% versus 22%, respectively), therefore they were considered the best technique for tagging the animals in the subsequent growth studies. From 2010 to 2013, a total of 1604 O. vulgaris (74.4% with a total weight <300 g) were tagged with discs and released in an area of the central western Sardinian Sea (western Mediterranean Sea). Ninety-one specimens were recaptured after 4–63 days of freedom, 59 of which (31 males and 28 females) showed positive growth increments after a minimum time of 8 days at liberty. In general, a high individual variability (0.96–9.09 g day−1) and higher mean daily growth rates in females (3.07–3.65 g day−1) than in males (2.08–2.98 g day−1) were recorded, but this difference was not statistically significant. Using tag–recapture data, the first exponential growth curves for both sexes of Octopus vulgaris of small–medium size from the Mediterranean Sea were obtained, and compared with those available in the literature for the species.

Today, three-spined stickleback Gasterosteus aculeatus are the most abundant fish in the White Sea and are close to their historical maximum. Based on observations from 2011–2013, this study reports quantitative and qualitative characteristics of juvenile stickleback diet during periods of active feeding in coastal Zostera seagrass beds. The following planktonic taxa dominated stomach contents: copepods Temora longicornis and Microsetella norvegica, ciliophora Helicostomella subulata. Benthic organisms such as Oligochaetae and Orthocladiinae also played an important role, whereas the literature suggests they were once rare in marine stickleback diets. Consumption patterns depended on fish size, with the most pronounced diet shift taking place as juveniles reached a length of 15 mm, in late August. In larger juveniles the highest correlation between the abundance of food organisms in stomachs and in the sea was observed for Orthocladiinae, suggesting that they are the preferred food. Overall, changes in diet followed changes in the abundance of available food organisms, but food selectivity analysis of planktonic organisms showed that M. norvegica were actively selected by juveniles.

Studies of sea turtle epibiosis have focused on the diversity and ecology of facultative commensalisms and less attention has been given to parasitic associations, in which the epibiont species derives nutrients from the tissue of the host turtle. We present the first description and quantitative survey of the parasitic isopods Excorallana costata, Excorallana bicornis and Excorallana oculata on loggerhead (N = 79) and hawksbill turtles (N = 23), and E. costata on olive ridley turtles (N = 9), nesting on Praia do Forte, Bahia, Brazil during the 2009–2010 season. Excorallana costata was the most common isopod species (N = 651), followed by E. bicornis (N = 77) and E. oculata (N = 20). Patterns include: (1) E. costata exhibited a higher frequency and intensity of parasitism than E. bicornis and E. oculata and (2) loggerheads hosted parasitic isopods at a higher frequency and intensity than hawksbills and olive ridleys. We also detected temporal shifts in the occurrence and intensity of parasitism across the nesting season, which strongly suggests that turtles were parasitized by all three isopod species during their internesting periods. Because parasitic isopods were observed only rarely prior to the 2009–2010 turtle-nesting season and have continued to be common in subsequent seasons, it is important to gain a better understanding of the basic biology of these interactions, the reasons for their recent emergence, and the potential biological impacts on turtle, as well as isopod, populations.

Growth rates and size-age at maturity are life history traits that combine in different ways to achieve maximal fitness. The marine scavenger Buccinanops globulosus was used as a model to explore the variation on female size-age at maturity and reproductive effort among three populations characterized by different growth rates (slow, moderate and rapid). This species constitutes the target of an artisanal fishery in North Patagonia. Here, a suite of different estimators of size-age at maturity derived from gonad histological analysis and the study of females carrying egg capsules were obtained. Data were modelled using a logistic function and the maturity patterns were compared among populations. We found that female size and age at maturity were variable and site-specific. The fastest-growing population showed the lowest reproductive effort. Slow and rapid-growing females mature at different sizes but at the same age whereas moderate-growing females mature both at a different size and age (intermediate size and at earlier age). Thus, results obtained here are difficult to reconcile with a single reaction norm for a single genotype in the studied populations. Growth rate variation is not enough to explain the patterns described here. The information provided could be used for the establishment of fishery management actions, such as minimum landing size.

The age, growth, longevity, mortality and reproductive parameters were estimated for Dipturus oxyrinchus from the Gulf of Gabès (Southern Tunisia, central Mediterranean Sea), collected monthly during 2007 from commercial fisheries. The present study provides the first data on age and growth of this species in Tunisian waters, as well as additional data on its reproduction. A total of 240 females (16.5–105 cm total length (TL)) and 280 males (15.5–95 cm TL) were examined to study the reproductive cycle. A subsample of 285 specimens (175 females and 110 males, ranging from 15.5 to 105 cm TL) were analysed to study the age and growth. The oldest female in this study was 25 yr and 105 cm TL, whereas the oldest male was 22 yr and 95 cm. The annual deposition of growth bands was verified by marginal increment and edge analysis. The von Bertalanffy growth parameters were L∞ = 123.9 ± 2.56 cm, K = 0.08 ± 0.004 yr−1 and t0 =  −1.26 ± 0.04 10−1 yr for females and L∞ = 102.1 ± 3.23 cm, K = 0.12 ± 0.007 10−3 yr−1 and t0 = −1.18 ± 0.03 10−1 yr for males. Growth was not significantly different between sexes. The maturity size was 72.05 cm for males and 82.1 cm for females. The maturity age was estimated to be 11.95 and 13.96 years, respectively, for males and females. Size and age at maturity were not significantly different between sexes. The estimated longevity was 26.18 and 38.84 yr for males and females, respectively. Based on life history parameters, natural mortality was estimated at 0.53 yr−1 for females and 0.41 yr−1 for males.

We analysed 267 zooplankton samples collected in the South Brazilian Bight (SBB; 23–27°S) to determine whether hydroids, typically benthic, are common components of the pelagic SBB. Two species, Clytia arborescens, recorded for the first time in the Atlantic Ocean, and Clytia sp. were identified. While these planktonic hydroids were frequent or relatively so in shallow shelf waters (~23% of the samples <50 m isobaths, and 5% of the samples >100 m), abundances were low (up to 61 hydranths m−3) suggesting a low trophic impact. Such colonies are probably fragments of benthic colonies detached by storms and/or tides. Given the good condition of the coenosarc, existence of gastric content, and presence of reproductive structures, development of these species appears to be normal in the pelagic environment. Existence in the plankton may increase their capacity for dispersion.

Re-examination of the holotype male of Zehntneriana villosa (Zehntner, 1894) (from Ambon, Indonesia) shows that Japanese specimens previously referred to this species should be designated as a new species, Zehntneriana tadafumii sp. nov. The new species differs from Z. villosa in several characters, including the carapace, epistome, third maxilliped and thoracic sternum. Here, we redescribe and illustrate Z. villosa s. str. and the new species. In addition, the taxonomy of Zehntneriana Ng & Takeda, 2010, is also discussed.

Newtoniellinae is a worldwide marine group of cold-water, deep-sea species, comprising the genera Cerithiella, Paramendax and Trituba. Prior to this study, the subfamily was represented in Brazil by four species of Cerithiella. The present contribution adds new Brazilian records of two of these species, Cerithiella amblytera and Cerithiella enode, in addition to new records of two species previously known only from Cuba and the south-eastern USA, respectively: Cerithiella sigsbeana comb. nov. and Cerithiella producta. Two new species of Cerithiella from Brazil are described: Cerithiella atali sp. nov. has a pointed protoconch identical to the species described in the previously synonymized genus Stilus; Cerithiella candela sp. nov. has the teleoconch very similar to Cerithiella pernambucoensis, but is differentiated by the protoconch morphology. Also, a new species of Trituba is described, Trituba anubis sp. nov., which is the second species of this genus recorded for the western Atlantic. Eumetula axicostulata comb. nov. and Eumetula vitrea comb. nov., both from the western Atlantic but not recorded from Brazil, are transferred from the genus Cerithiella. This study increases from four to nine the number of known species of Newtoniellinae from Brazil.

Doris verrucosa Linnaeus, 1758 is the type species of Doris, the type genus of Dorididae. Its currently accepted distribution includes the Mediterranean, Eastern (Europe and Africa) and Western Atlantic (Massachusetts, USA to Santa Catarina, Brazil). Until now, papers on the anatomy of this species dealt with restricted characters such as rhinophores, radula and reproductive organs, never comparing specimens from different localities. In this study we have examined the anatomy of species similar to D. verrucosa from the Brazilian coast, and compared them with samples of D. verrucosa from Europe, the type locality. After an extensive complementary anatomical study of the circulatory, excretory, digestive, reproductive and nervous systems, the identity of the Brazilian specimens is clarified, proving that they belong to a different species. To solve the consequent nomenclatural gap, we revalidate Staurodoris januarii Bergh, 1878, described from Brazil, transferred to the genus Doris. The nominal species Doris verrucosa is, therefore, restricted to European waters.

Length-weight relationship, growth parameters and mortality rates of Anadara granosa in the intertidal zone of Balik Pulau, Penang Island, West Coast of Malaysia were investigated based on monthly length-frequency data (December 2011 to November 2012). A total of 548 individuals ranging from 11.25 to 33.13 mm size were subjected to analysis. Logarithmic relationship between the length and weight was Log W = 2.328 Log L − 2.537 (R2 = 0.922) for combined sexes. From this equation it was clear that the exponent ‘b’ value for A. granosa showed a negative allometric growth (b < 3). A von Bertalanffy growth function with an asymptotic length (L∞) of 35.40 mm and a growth constant (K) of 1.1 year−1 was established from length frequency distributions. The t0(−0.140) was estimated by substituting the L∞and K in the Pauly's equation. The sizes attained by A. granosa were 10.13, 14.36, 17.89, 20.82, 23.56 and 25.29 mm at the end of 2, 4, 6, 8, 10 and 12 months, respectively. The estimated growth performance index (Ø) was 3.13 while the estimated lifespan of the cockles was about 2.72 years at the study area. The estimated value of total mortality based on length-converted catch curve was Z = 3.02 year−1. The natural mortality (M) and fishing mortality (F) rates were 1.84 and 0.48 year−1, respectively. The exploitation level (E) of A. granosa was 0.20, which indicated slight fishing pressure on the stock.

The increasing market demand for Glyptocidaris crenularis shapes its great potential for aquaculture. Temperature is an important factor affecting gonad production and quality of sea urchins. Therefore, it is essential and valuable to carry out an evaluation of the temperature effects on gonad production and quality in G. crenularis before potential aquaculture. Here, we investigated the long-term effects of temperature on gonad production, colour and flavour in G. crenularis. There was no significant difference of test diameter, height and body weight between the sea urchins in high (16–23°C) and low (12–16°C) temperatures (P > 0.05). Glyptocidaris crenularis showed significantly higher gonad production and index in high temperature and in low temperature (P < 0.05). L*, a*, b* readings were slightly higher in the low temperature groups, although no significant difference was found (P > 0.05). Subjective colour and flavour ratings found that G. crenularis in the low temperature group showed significantly better colour (P = 0.003) and flavour (P < 0.001) than those in the high temperature group. The present study provides valuable and insightful information into the establishing G. crenularis aquaculture.