This paper describes the hydrography and the larval fish assemblage of Guinea Bissau waters, and analyses the spatial distribution of the main families in relation to the oceanographic features of the area. Data were obtained during an oceanographic survey, undertaken between October and November 2008. In addition to 98 demersal fishing hauls, a total of 33 stations, located between 20 and 1000 m depth, were sampled for hydrography and ichthyoplankton. Data showed that Guinea-Bissauan surface waters are characterized by a strong thermohaline front that flows parallel to the bathymetry of the area. Warm surface waters (SST > 29°C) occupy the inner shelf, and colder (SST < 26°C), chlorophyll-a-rich waters take over the shelf break. Continental runoff seems responsible for the low salinity of the inner-shelf waters whereas the colder types bear thermohaline features typical of tropical Atlantic waters. These features define a scenario which favours the development of fish early life stages, reflected in the high abundance and diversity of fish larvae recorded. A total of 84 taxa of fish larvae were identified. Only the family Clupeidae accounted for 54.8% of the sampled larvae. Other important families were Carangidae (8.8%), Sparidae (8.4%) and Myctophidae (5.9%).

Taxonomic composition and seasonal dynamics of density of phytoplankton, heterotrophic bacteria, ciliates, holoplankton, meroplankton and zoobenthos of mud bottom sediments were studied in 2010–2011 in the Liman ‘Zmeinoe Ozero’. Twelve non-native species of fauna were recorded, that penetrated into the Liman with ships' ballast water (established species – 6, cryptogenic species – 2, casual species – 4). The basic ‘groups of risk’ of invasions are tintinnids infusorians, neritic species of copepods and spionid polychaetes. The attempt to define the degree of vulnerability of the recipient ecosystem to biological invasions is made on the basis of an energy balance method. The prognosis of biological pollution of the north-eastern Black Sea by ships' ballast waters was executed.

Sanya Bay lies at the southern part of Hainan Island, 18°15′N 109°28′E. The seawater in the bay has been catastrophically polluted during the past two decades with urban sewage from the rapidly developing Sanya City. The marine flora research in Sanya Bay was started at the beginning of the 1930s and the most detailed studies were performed by two German-Chinese expeditions in 1990 (October–December) and in 1992 (March–April). In April, October, November and December 2008–2010 the marine flora of Sanya Bay was studied by the authors at three localities: Luhuitou Peninsula, Xiaodong Hai and Dadong Hai. Marine algae were sampled in the intertidal and upper subtidal zones (to 4–5 m depth). The list of species (including varieties and forms) of the marine algae for Sanya Bay sampled during the period from 2008 to 2010 is compared with those collected at the same localities in 1990/1992. Comparative analysis of the floristic composition of the marine red, brown and green algae (found during different time periods) revealed that considerable changes have taken place between 1990/1992 and 2008–2010 at Sanya Bay. There was an increase in filamentous, tubular and fine blade-like green and red algae (mainly epiphytes with a high surface to volume ratio) and a displacement of upright-growing fleshy, foliose and other large green, brown and red algae with a low surface to volume ratio. It is assumed that the changes reflect mainly increased pollution by urban sewage and mariculture pond wastes and probably by coral bleaching events of 1998.

We describe a new species of Crambionella, C. helmbiru, from central Java, Indonesia. The combination of the mean number of lappets per octant (14), presence of foliaceous appendages amongst frills on oral-arms, absence of tubercles on the velar lappets, proportion of terminal club length to oral-arm length (0.28), and the body colour distinguish this species from three previously described congeners. In addition, the analysis of partial sequences of the cytochrome c oxidase subunit I gene indicate substantial genetic differences from both Crambionella orsini and Crambionella stuhlmanni, supporting the validity of this new species. A combination of morphological and genetic approaches determined that the remarkable differences in exumbrellar colours observed in specimens are simply intra-specific variation. Surprisingly, this species has been commercially harvested for more than 20 years and is well-known to the local people in the region, yet it had remained unknown to science until this point. The commercial fisheries targeting this formerly unknown species are also described in detail.

We examined the spatial and temporal variations of coastal and oceanic epipelagic copepods (rainy–dry seasons of 2009) in a tropical area of the south-west Atlantic. Zooplankton samples were obtained at 48 stations along six transects perpendicular to the coast, in the subsurface water between the 25 and 3000 m isobaths, by horizontal hauls using a Multinet. Abundance (42–64,753 ind. m−3), biomass (0.08–113 mg C m−3) and daily copepod production (0.17–163.20 mg C m−3 d−1) showed longitudinal and latitudinal variability. The highest values were observed over the southern continental shelf during the dry season. Temoridae, Undinula vulgaris and Paracalanus quasimodo dominated the biomass and daily copepod production during the rainy season; while Calanoides carinatus, Calanopia americana, Clausocalanidae, Temoridae, Paracalanidae and Subeucalanidae dominated during the dry season. The copepod assemblages formed four different groups: rainy season–continental shelf (1), dry season–continental shelf (2), rainy season–continental slope (3) and dry season–continental slope (4). Temperature, salinity, chlorophyll-a and suspended particulate matter explained 45% of the productivity distribution of the dominant copepod species. This study is the first attempt to examine the biomass and daily copepod production in oceanic waters in the south-west Atlantic Ocean, and it showed that copepod biomass and production in a tropical region can be relatively high compared with other regions of the world's oceans.

Identification of marine invertebrate larvae using morphological characters is laborious and complicated by phenotypic plasticity. Balanus amphitrite is a dominant barnacle, important in the context of intertidal ecology and biofouling of manmade structures. Morphological identification of barnacle larval forms in a mixed population is difficult because of their intricacy and similarity in size, shape and developmental stages. We report the development and application of a nucleic acid-based Polymerase Chain Reaction (PCR) method for the specific identification of the barnacle, B. amphitrite, from the heterogeneous zooplankton sample. This method is reliable and accurate thereby overcoming taxonomic ambiguity. Sequence alignment of the 18S rRNA gene region of selected species of barnacles allowed the design of B. amphitrite-specific PCR primers. Assay specificity was evaluated by screening DNA obtained from selected species of barnacles. The oligonucleotide primers used in the study flanked a 1600 bp region within the 18S rRNA gene. The primer is specific and can detect as few as 10 individuals of B. amphitrite larvae spiked in a background of ~186 mg of zooplankton. This technique facilitates accurate identification and the primer can be used as a marker for enumeration of B. amphitrite larvae in the plankton.

Hyperiid amphipods are holoplanktonic marine crustaceans that are known as temporary symbionts of different groups of gelatinous zooplankton. The nature and dynamics of these associations are still poorly understood, particularly in deep waters. The mesopelagic and deep-living planktonic fauna off Monterey Bay, California (down to 4000 m) was surveyed using a remotely operated submersible (ROV) and blue-water diving (BWD) between September 2005 and January 2008. In this work we report our observations on a total of 51 symbiotic associations observed in situ (not from zooplankton samples), between hyperiid amphipods and various taxa of gelatinous zooplankton. We present the first information on the symbiotic relations of the hyperiid Vibilia caeca, and we provide data of 34 previously unknown symbiotic associations. The host range was expanded for several widely distributed hyperiid species. These findings suggest that the symbiotic associations between hyperiid amphipods and gelatinous zooplankton in deep waters deserve further study worldwide.

Although Parthenopidae is a brachyuran decapod family comprising almost 140 species, there is little knowledge about its larval morphology. There are only two complete larval developments reared in the laboratory and some larval stages described for seven species. In the present work these data are compared and analysed. A summary is made of the larval features that characterize parthenopids that can be used to distinguish them from other brachyuran larvae. In addition, the megalopa stage of Derilambrus angulifrons and Parthenopoides massena was collected from plankton and identified by DNA barcodes. The morphology of the megalopa of D. angulifrons is described for the first time, and that of P. massena is compared with a previous description.

The deep brine pools of the Red Sea comprise extreme, inhospitable habitats yet house microbial communities that potentially may fuel adjacent fauna. We here describe a novel bivalve from a deep-sea (1525 m) brine pool in the Red Sea, where conditions of high salinity, lowered pH, partial anoxia and high temperatures are prevalent. Remotely operated vehicle (ROV) footage showed that the bivalves were present in a narrow (20 cm) band along the rim of the brine pool, suggesting that it is not only tolerant of such extreme conditions but is also limited to them. The bivalve is a member of the Corbulidae and named Apachecorbula muriatica gen. et sp. nov. The shell is atypical of the family in being modioliform and thin. The semi-infaunal habit is seen in ROV images and reflected in the anatomy by the lack of siphons. The ctenidia are large and typical of a suspension feeding bivalve, but the absence of ‘guard cilia’ and the greatly reduced labial palps suggest that it is non-selective as a response to low food availability. It is proposed that the low body mass observed is a consequence of the extreme habitat and low food availability. It is postulated that the observed morphology of Apachecorbula is a result of paedomorphosis driven by the effects of the extreme environment on growth but is in part mitigated by the absence of high predation pressures.

The pearl oyster, Pinctada radiata, shows great variation in shell morphology throughout its distribution. This variation can be related to phenotypic plasticity, genetic variability or a combination of both. Using geometric morphometric and microsatellite DNA analyses, two morphologically distinct populations of the pearl oyster were studied in the northern Persian Gulf, i.e. from the Lavan and Hendourabi Islands. Ten landmarks were selected to define the shape of the left shell. In addition, concentration of Zn, Mg, Fe, Cu, Pb, Cd, Mn and Cr of the soft tissues were measured using atomic absorption spectrometry. Six microsatellite loci were used to assess the population genetic structure of the pearl oyster. There were morphometric differences between the populations suggesting the existence of two morphotypes. There was a significant difference between the two populations in concentrations of Fe, Mg, Zn, Cd, Mn and Cr indicating that the specimens from the Lavan Island experience a more stressful environment than those from the Hendourabi Island. Analysis of molecular variance (AMOVA) indicated that the proportion of the genetic variation attributed to differences among populations of the pearl oyster was highly significant for both FST and RST (FST = 0.066, RST = 0.265, P < 0.001). Our findings showed that stressful conditions resulting from heavy metals may have a direct influence on the separation of the populations in Lavan and Hendourabi despite the lack of a physical barrier.

The occurrence of the alien species Anadara kagoshimensis is reported for the first time in the Ría de Arousa (Galicia, NW Spain) during 2013. Living specimens of this species have been recognized by morphological analysis. The cytochrome c oxidase subunit I gene has been partially sequenced and Maximum likelihood and Bayesian analyses carried out to confirm its identification. This new record reaffirms the presence of A. kagoshimensis, previously reported as Anadara inaequivalvis, along the Atlantic European coast extending the known distribution range in Spanish waters to the south.

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.

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.

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.

Dolphinfish (Mahimahi) are a high-demand resource for sport and coastal fisheries, mainly in the Pacific Ocean. Due to their economic and ecological importance, studies of their biology are very important to understand their function in ecosystems. We used stable isotope and stomach content analyses to determine the most important prey of the common dolphinfish, as well as the trophic level of this species in two areas of the southern Gulf of California. Stomach contents of 445 specimens were analysed. Using both techniques, we found that the most important prey for dolphinfish in the southern Gulf of California were three invertebrate species followed by fish. This contrasts with results from other authors who found that this species was mainly piscivorous in other locations. Stomach content analysis indicated differences in prey biomass by area, season and size class. The isotopic analysis did not show significant differences between seasons or sexes. Both stomach contents and stable isotope analyses showed that although this predator consumed a wide prey spectrum, only a few prey items made up the bulk of the diet, which resulted in a low SD in δ15N values and low Levin's index values. We conclude that this fish is an opportunistic predator that may consume a wide prey spectrum, but that it mainly consumes prey that are abundant in the area, such as crustaceans and cephalopods in the Gulf of California.

The present work aimed to investigate possible spatial and seasonal patterns in the distribution of two sympatric serranids, the painted comber, Serranus scriba and the comber, Serranus cabrilla. The research took place at a NATURA 2000 site located at Sithonia peninsula, N. Greece. Underwater visual census was used for data collection; specifically, individuals from each species were recorded along four isobathic transects of 200 m2 each, placed every 5 m and ranging from 5 to 20 m depth. A total of 27 samplings were conducted between September 2010 and August 2011. The results clearly demonstrated complementary bathymetric distributions for S. scriba and S. cabrilla, the former mostly occurring until 10 m depth, and the latter in deeper layers. This pattern was maintained during the whole season. In addition the two species exhibited differences in their preferred substrate type and their pattern of association to the sea bottom. Our results were viewed under the light of resource portioning between the two sympatric species.

The grouper Cephalopholis taeniops is a carnivorous fish of the Cape Verde coastal marine ecosystem. Nothing is known regarding the age and growth of this epinephelid. In this study, the age and growth of C. taeniops was investigated by annual growth increment counts from 2804 specimens (7–51 cm total length) collected between January 2005 and December 2011. Whole otoliths underestimated the age indicated in sections by approximately 70%; therefore, sectioned otoliths were used in this study. A year's growth was represented by one opaque and one translucent ring. There was no apparent time lag from the start of the increase in the seawater temperature and the beginning of the formation of the opaque ring. The formation of the translucent rings coincided with a decrease in surface seawater temperature. Cephalopholis taeniops is a slow-growing and long-lived species, with ages of up to 20 years recorded. The seasonalized von Bertalanffy growth function was the best fitted among the four models tested, with an Akaike weight higher than 0.99. Growth was described by the seasonalized von Bertalanffy growth function as follows: L∞ = 54.26 cm, k = 0.135 year−1, t0 = −0.853 year, C = 0.439 and ts = 0.667.

The present research provides detailed information on the geographic and bathymetric distributional patterns of fishes and describes the main species assemblages of the continental shelf and upper slope off El Salvador. The sampling was based on 673 bottom-trawl tows taken during research surveys from April to November 2003. The data analysis was based on presence-absence matrixes and was conducted with PRIMER 6 software. A total of 148 fish species were recorded during the study period: the families with the highest number of species were Sciaenidae (13) and Carangidae (10), and the highest percentages of occurrence were registered for Porichthys margaritatus (40.6%), Pontinus sp. (34.8%) and Monolene dubiosa (33.1%). The cluster analysis by depth showed three faunistic associations: (1) on the inner and part of the mid continental shelf (20–60 m), (2) one bathymetric stratum on the mid continental shelf (80–100 m), and (3) on the outer continental shelf and upper slope (120–240 m). The cluster analysis by geographic zones showed separation between three zones: Western, Central and Eastern Zones off El Salvador. The Central zone is characterized by a different fish community of mixed habitat, while the main factor that determined the fish assemblages on the continental shelf and upper slope was depth.

Based on data from 151 underwater surveys (scuba) between 2002 and 2007, the present study assessed the reef fish fauna from a scarcely known region on the north-eastern Brazilian coast (Ceará State). A checklist of 179 taxa is provided and the zoogeographic patterns are analysed and discussed, including six other localities. Based only on assemblage composition, the reef fish fauna from Ceará showed a strong resemblance (73%) with the reefs of Risca do Zumbi (RN) and Paraiba (PB). The data from the visual censuses including abundance values corroborate the evaluation based only on composition and suggest ecological factors as the main drivers of the fish assemblages in the region.