Bioactive compounds of gonad, respiration tree, cuvierian organ, and body wall of the sea cucumber Holothuria leucospilota collected from the north coast of the Persian Gulf were extracted using ethyl acetate, methanol and water–methanol solvents. Extracts were evaluated for their antibacterial and antifungal activities against Aspergillus niger, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The activity was determined using the disc diffusion test. Cytotoxic activities of the extracts were determined by brine shrimp lethality assay. Results demonstrated that the A. niger was shown to be the most sensitive microorganism followed by C. albicans. The inhibition zone against A. niger and C. albicans had minimum inhibitory concentrations ranging from 3 to 7 μg/ml. The highest antifungal activity was found in G (water–methanol) with an inhibition zone of 50 mm against A. niger at 18 μg/ml extract concentration continuing with CT (methanol) with 46 mm inhibition zone against A. niger at 18 μg/ml extract concentration. The highest cytotoxic effect of methanol extract was found with LC50 values of about 40.31 μg/ml in the gonad organ from H. leucospilota continuing with the respiration tree organ with LC50 values of about 72.49 μg/ml.

The nucleotide sequences of mitochondrial DNA fragments containing genes for cytochrome c oxidase subunits I and II, ATPase subunits 6 and 8, large and small subunits of rRNA, and 9 tRNAs were determined using 2 genetically distinct representative specimens of the hydrothermal vent-endemic genus, Alviniconcha, and for the hydrothermal vent-endemic species, Ifremeria nautilei (Provannidae: Caenogastropoda: Mollusca). All 3 specimens showed tRNATrp gene translocation. To determine the time point at which this translocation occurred, we determined the nucleotide sequences of fragments containing 7 tRNA genes for another 3 Alviniconcha and 2 Ifremeria specimens, as well as for 7 related species. Our findings indicated that the translocation occurred in a common ancestor of the Alviniconcha and Ifremeria genera. Relatively long non-coding regions were observed on both sides of the tRNATrp gene and at the original position of this gene in all the Alviniconcha and Ifremeria gastropod specimens. Overall, the mitochondrial non-coding regions appear to provide much more information about genetic structure than the mitochondrial COI gene does and could therefore be a valuable marker for future studies.

Growth rates of newly-metamorphosed urchins from a single spawning event (three males and three females) were highly variable, despite being held en masse under identical environmental and nutritional conditions. As individuals reached ~5 mm diameter (0.07–0.10 g wet weight), they were placed in growth trials (23 dietary treatments containing various nutrient profiles). Elapsed time from the first individual entering the growth trials to the last individual entering was 121 days (N = 170 individuals). During the five-week growth trials, urchins were held individually and proffered a limiting ration to evaluate growth rate and production efficiency. Growth rates among individuals within each dietary treatment remained highly variable. Across all dietary treatments, individuals with an initially high growth rate (entering the study first) continued to grow at a faster rate than those with an initially low growth rate (entering the study at a later date), regardless of feed intake. Wet weight gain (ranging from 0.13–3.19 g, P <0.0001, R2 = 0.5801) and dry matter production efficiency (ranging from 25.2–180.5%, P = 0.0003, R2 = 0.6162) were negatively correlated with stocking date, regardless of dietary treatment. Although canalization of growth rate during en masse early post-metamorphic growth is possible, we hypothesize that intrinsic differences in growth rates are, in part, the result of differences (possibly genetic) in production efficiencies of individual Lytechinus variegatus. That is, some sea urchins are more efficient in converting feed to biomass. We further hypothesize that this variation may have evolved as an adaptive response to selective pressure related to food availability.

Seventeen chondrichthyan species were caught in the Cantabrian Sea (southern Bay of Biscay) during a multidisciplinary survey carried out in the Avilés canyon system in May 2011. This survey provided the first records of three species (Galeus murinus, Neoraja iberica, and Neoraja caerulea) in these waters, and a further record of Rajella kukujevi. To confirm the identity of these species, the cytochrome c oxidase subunit I (COI) of the specimens was sequenced. Genetic analyses revealed that the DNA sequences of the two Neoraja species were identical in all the specimens analysed. Morphometric analyses, based on 40 characters, showed 3.66% dissimilarity between the two species. The morphometric character that contributed most to this discrepancy was disc width.

The diet and feeding habits of the sharpsnout seabream, Diplodus puntazzo, from the Gulf of Gabès were investigated using stomach contents of 490 specimens ranging from 12.6 cm to 26.1 cm total length in size and from 29.95 g to 230.83 g in weight collected from commercial catches between April 2008 and March 2009. Of the total number of examined stomachs, 279 were empty (%VI = 56.94). This percentage varied significantly with months, attaining a maximum in spring (74.88%) and a minimum in autumn (37.38%). Eight major taxa were identified (Plantae, Spongia, Tunicata, Echinodermata, Crustacea, Annelida, Mollusca and Teleostei) in stomach contents of D. puntazzo. Plants were the most important food source, constituting 89.88% of the total Index of relative importance. The other groups, such as teleosts, molluscs, crustaceans and annelids represented accessory food. Significant differences in diet were observed in relation to season. Plants were the most important food source item in all seasons, especially during the autumn. The estimation of trophic level gave an average of 2.57 ± 0.2 for the whole population of D. puntazzo in the Gulf of Gabès. Based on the composition of its diet, this species may be considered as an omnivorous fish with a preference for vegetable material, and showing specialist feeding strategy.

The genetic relationship between fiddler crab Uca crassipes populations from the continental coast, continental islands, and oceanic islands in the west Pacific was investigated using 1039 bp (base pairs)-long combined 12Sr-RNA–16Sr-RNA sequences and a 504-bp mitochondrial DNA control region. The combined 12Sr-RNA–16Sr-RNA sequences indicated that the Vietnamese population, located along the continental coast, and the Chichi-jima population, which is located on an oceanic island north of the Northern Mariana Islands, formed different clades than populations from the other Ryukyu Islands and Moorea Island. Conversely, the Ryukyu Islands and Moorea Island populations exhibited a close genetic relationship, although the mtDNA control region indicated significant differentiation between the Ryukyu Islands and Moorea Island populations. The isolated Vietnam and Chichi-jima populations exhibited higher genetic diversity in the control region than the other populations.

Bottom trawling is a large-scale fishing activity along the Brazilian coast, but its effects on benthic infauna are still poorly known. This is the first experimental evaluation of benthic responses to bottom trawling along the Brazilian coast. We tested the effects of trawling on macroinfaunal assemblages on the inner continental shelf off Paraná (southern Brazil) by using a sampling design with adjacent trawl and control areas. We hypothesized that if trawl fishing has a negative effect then we should expect lower numbers of species and lower benthic densities after an experimental trawling. Sampling was conducted at adjacent sites within each area to minimize confounding due to spatial variation. Five sites were sampled at a control, and five at an experimental area for infaunal and sedimentological variables. Sampling was carried out just before and one hour after experimental trawling. Multidimensional scaling followed by a PERMANOVA did not show any clear variation tendencies in the structure of the benthic assemblages in the impacted area before and after trawling. However, variance analysis showed a significant and unexpected increase in infaunal total density, in the density of the numerically dominant species (except for the polychaetes Capitella sp. and Loandalia tricuspis) and in species richness in the experimental area. Conversely, no significant variations were recorded in the control area. We suggest that the overall increase in benthic density after a disturbance is correlated with the reworking of the sediment matrix and benefits the suspension-feeders after sediment resuspension.

The ectoparasitic gastropod genus Cerithiopsis Forbes & Hanley, 1850 was nominally based on Murex tubercularis Montagu, 1803. We have used the DNA barcode COI sequences to assay sympatric samples of morphotypes recently described as distinct species of the Cerithiopsis tubercularis-complex. Our results demonstrated that, in the Croatian waters, the gastropods usually called C. tubercularis in fact comprise a complex of cryptic species, which can be reliably diagnosed only by examining the soft parts. In the present study we have demonstrated that the colour pattern of the head-foot is diagnostic at the species level in this complex and, coupled with genetic data, may provide a sounding base for a revision of the cerithiopsids of the European coasts.

The black goby Gobius niger (Linnaeus, 1758) (Gobiidae) is one of the most common gobies in southern Tunisian waters. This study provides the first detailed information on the reproductive biology of the G. niger in these areas. Samples of G. niger were collected by trawl from the Gulf of Gabès (Tunisia) between February 2009 and January 2010. A total of 1055 specimens were examined, ranging from 6.4 to 15.7 cm total length. The sex-ratio was in favour of males, especially in larger size-classes. The macroscopic analysis of the gonads and the progression of the monthly values of the gonadosomatic index (GSI) indicated that the reproductive season extended from March to June, with GSI peaking in May, and that spawning occurred from April to June. The utilization of lipid reserves, stored predominantly in the liver as well as in muscles, was important during the reproduction season. Monthly changes of the seminal vesicle somatic index showed that during the pre-spawning period they had a proliferation phase, followed by a regressive phase during the post-spawning period. Total fecundity of mature females ranged from 4280 to 14000 eggs per fish, showing a significant increase with size, with an average of 8522 ± 689 eggs per fish. The total length at 50% maturity was 10.13 ± 0.3 cm and 9.69 ± 0.18 cm for males and females, respectively.

We monitored the long-term residency of reef-associated ballan wrasse and sand-dwelling rays captured at the site of a potential future Marine Protected Area (MPA: Portelet Bay, Jersey) by implanting them with small transmitters and deploying underwater receivers inside the bay. Individual fish were detected at Portelet Bay for up to 618 days, but there were species-specific differences in residency and detection patterns. Ballan wrasse were year-round residents at the study site where they exhibited distinct, rhythmic, diel, tidal and seasonal patterns of behaviour, whereas rays were occasional visitors to Portelet Bay with no discernible pattern to their visits. Results indicate relatively small MPAs (<0.5 km2) that with suitable habitat could provide effective, long-term protection for ballan wrasse, but would likely be of little conservation benefit for rays. Our findings emphasize the importance of quantifying fish movements when planning MPAs which intend to protect multi-species assemblages of coastal fishes.

This study presents new information on the population biology, growth and maturation schedules of Galeus melastomus, Centroselachus crepidater and Apristurus aphyodes sampled from the Rockall Trough, a region where deep sea fishing activity has been prevalent for the past 40 years and where shark by-catch is considerable. Both G. melastomus and C. crepidater showed significant sexual size dimorphism with females attaining a greater length and mass. The size (L50) at first maturity was estimated to be 55.6 cm total length (TL) for males and 59.7 cm TL for females in G. melastomus, 57.2 cm TL for males and 75.4 cm TL for females in C. crepidater and 49.0 cm TL for males and 56.9 cm TL for females in A. aphyodes. This represents the first TL50 analysis for Apristurus aphyodes globally. Sharks were aged using a technique which employed cobalt (II) nitrate to stain growth bands in vertebra centra. Band pairs were successfully viewed in G. melastomus and pair counts ranged from 0 to 5 in males and 2 to 7 in females. A higher asymptotic length was deduced from the von Bertalanffy growth equation for females than males (females: L∞ = 69.3 cm; males: L∞ = 60.8 cm) in G. melastomus. Staining was unsuccessful in C. crepidater and A. aphyodes and age could not be determined using this technique.

The ectoparasite community of the blackspot seabream, Pagellus bogaraveo, was studied in different locations in Portuguese waters of the north-east Atlantic Ocean. This is the first study to focus on the ectoparasites of this commercially important sparid fish. Nine ectoparasite species were detected. Gnathia sp., Aega deshaysiana, A. antillensis, Rocinela danmoniensis and Argulus sp. are reported for the first time on this host. Significant differences were detected among the sampling locations, with monogeneans being more prevalent in mainland waters, and crustaceans being more prevalent in the Atlantic islands of Madeira and Azores. Fish from Madeira showed significantly higher infection levels of all ectoparasites, especially crustaceans, and particularly high prevalence of Hatschekia pagellibogneravei. The potential impact of the species detected on captive fish is also discussed, since the blackspot seabream is a promising new species for marine aquaculture.

The larval development of the Russell's snapper Lutjanus russellii is described and illustrated for the first time. Fertilized eggs, with a mean diameter of 0.80 ± 0.04 mm and a range from 0.71 to 0.84 mm, were spherical, transparent, buoyant and unpigmented. Embryonic development lasted 26 hours 50 minutes at 24.7°C. Newly hatched larvae were 1.86 ± 0.10 mm in total length (TL) with 24 (10 + 14) myomeres and had an oil globule in the ventroanterior area of the yolk sac. Two days after hatching (DAH, 2.61 mm TL), the mouth opened. Early larvae had melanophores scattered on the head, body and yolk surface. Thirteen DAH (2.74 mm TL), the buds of the second dorsal and pelvic-fin spines had appeared. At 5.81 mm TL, the notochord was slightly flexed, and the hypural bones and caudal-fin rays had begun to develop. The ratios of the second dorsal and pelvic-fin spine lengths to TL attained their maximum, 40% and 36%, respectively. At 14.02 mm TL, all fins had the adult complement of rays and spines. The characteristic of this species, with four black stripes on the sides and with a round black spot on the upper back, was completed in juvenile of 23.1 mm TL. The larval habitat shifted from the surface and middle layers to the tank bottom. A statistical model: Y equals 2.18e0.06X, where Y is mean TL (mm) and X represents DAH, explained 99.34% of variation in growth (P < 0.001, R2 = 0.9934).

Population density and the presence of fission products of Holothuria (Halodeima) atra were investigated in surveys taken over 5 years (2006–2010) in the Capricorn Bunker Group, Southern Great Barrier Reef. These surveys were undertaken to document population density over time and assess the potential that asexual reproduction contributes to population maintenance. Over the 5 years a low incidence of fission was evident year-round, with an increase in July and August (13 and 27% of the population, respectively). There was a positive correlation between population density and the presence of fission products across all surveys. Although density fluctuated, there was no significant difference between months or sites. Despite the potential increase that might be expected from fission followed by regeneration, density fluctuated around a mean of 0.77 ind. m−2. Examination of gonads of the small (asexual and sexual reproduction) and large (sexual only) morphs of H. atra indicated a difference in reproductive pattern. Many small morphs lacked gonads during winter and, when they developed gonads, the gonad index (GI) was low. The GI pattern of the small morph indicated that they spawned in summer. In comparison the large morph had conspicuous gonads through the year. The GI of the large morph was high in winter and summer indicating greater, more prolonged spawning activity in these individuals.

Oceanographical processes, such as upwelling, induce variations in nutrient availability in marine ecosystems, and evidence indicates that nutrient input can strongly influence the physiological activities, structure, and dynamics of marine communities. Intertidal organisms have long been considered ideal study units in which to quantify the relationship of physical variations and differential energy allocations in specimens that undergo environmental variations, such as observed with nutrient availability. In habitats with differential nutrient input (upwelling versus non-upwelling), both food availability (algae abundance) and seasonal gonadal and foot weight variations were determined in the keyhole limpet Fissurella crassa. Gonadal weight is used as a measure of reproduction allocation whereas foot weight is an indirect indicator of energy allocation towards survival. RNA:DNA ratio in limpets was used as an indicator of biosynthetic capability. Our results indicate that, in general, algae abundance, muscular foot weight, and gonadal weight were higher in upwelling sites during all seasons studied. The same result was found for RNA:DNA ratios. Energetic allocation in animals that inhabit intertidal upwelling habitats supported a constant allocation towards reproduction and soft tissues. In contrast, animals that inhabit non-upwelling habitats showed important energetic restrictions associated with higher water temperature and lower food availability. Our results clearly show that in the keyhole limpet F. crassa food availability is a more important determinant of an individual's condition than a physical variation such as environment temperature.

The pollack, Pollachius pollachius, is an important commercial species for the Spanish artisanal fleet in Atlantic Iberian waters. This study provides information on the reproductive biology of the species, including length at maturity, reproductive cycle and gamete development pattern based on histological methods. A collection of 622 individuals were sampled from fish markets along the western coast of Galicia (NW Spain), between November 2009 and October 2010. Histological examination of the gonads revealed an asynchronous development of secondary growth follicles. Testicular tissue was of lobular type. The reproductive season extended from January to April for females and from January to May for males, with a peak of reproductive activity in February for both sexes. The hepatosomatic index was related to the reproductive cycle, with a mean maximum value during the developing reproductive phase. Length at 50% maturity was significantly different between females (47.1 cm) and males (36.1 cm).

Samples of common two-banded seabream Diplodus vulgaris (N = 1097), used in this study, were caught in the Gulf of Gabès (Tunisia) from March 2008 to February 2010. Total length ranged from 7 to 25 cm. Diplodus vulgaris is a protandric hermaphrodite. The overall ratio of females to males was 1:1.66. The reproductive season extended from October to February, and the peak spawning activity occurred in December–January. The total length at which 50% of the population reached maturity was 14.14 ± 0.16 cm for females and 13.57 ± 0.01 cm for males. Parameters of the length–weight relationship (TW = aTLb) for all individuals were a = 0.0185 and b = 2.9319. The youngest specimen in this study was 0+ years, whereas the oldest one was 9 years. The von Bertalanffy growth parameters for the whole sample were: L∞ = 25.4 cm, k = 0.179 and t0 = −1.631 year. The instantaneous rate of natural mortality was: M = 0.333 year−1.

In local reef fish communities, species richness increases with increasing reef area. At Ishigaki Island, Japan, species richness is much lower on large reefs in the shallow back reef than that expected from random placement model simulations (RPMS). As three aggressive territorial herbivorous damselfish, Stegastes nigricans, Stegastes lividus and Hemiglyphidodon plagiometopon, coexist only on such large reefs, we focused on these species and examined patterns of their distribution and abundance on 84 patch reefs of various sizes (area and height). We also examined their aggressive intra- and interspecific behavioural interactions and habitat use on the two large reefs (the largest complex patch reef and the large flat patch reef) among the 84 patch reefs. While the abundance of both S. lividus and H. plagiometopon was highly correlated with patch reef area, that of S. nigricans was closely correlated with patch reef height. For S. nigricans and S. lividus, interspecific interactions occurred significantly more frequently than intraspecific interactions on the large flat patch reef. However, there was no significant difference in frequencies of the two interaction types on the largest complex patch reef, where they three-dimensionally segregated conspecific territories. This study suggested that reef height as well as reef area influence the distribution and abundance of these territorial herbivorous damselfish in the shallow back reef. As large patch reefs cannot be tall allometrically in shallow back reefs, relatively flat patch reefs may not have the high species richness expected from RPMS based on reef area.