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.

The sailfish Istiophorus platypterus is one of the most common billfish species in the Mexican Pacific. Information about its feeding habits in the coastal region of Acapulco, Guerrero is extremely limited. In the present study we quantified the diet of sailfish, based on captures made from March 2008 to December 2009 by the sport fishing fleet of Acapulco. We analysed a total of 561 stomachs, of which 254 contained food (45%). The size interval of examined specimens was between 101 and 212 cm postorbital length and between 15 and 47 kg total weight. In general, teleosts were the most important prey, followed by cephalopods. According to index of relative importance, the most important species in the diet were the fish Auxis thazard (63.04%) and Fistularia commersonii (6.62%), followed by the cephalopod Octopus spp. (4.58%). There were no significant differences in the diet by sex (males and females), sexual maturity (immature and mature), or by season (warm and cold seasons). In all cases the most important prey species was A. thazard. We conclude that the sailfish I. platypterus off Acapulco behaves as a specialist predator because, despite the consumption of a high number of prey items, it feeds preferentially on a reduced number of prey species that form schools, and are available and abundant in the ocean.

The reproductive cycle of the deep-sea eel Nettastoma melanurum was described based on 397 specimens (171 males and 226 females). Experimental trawl surveys between depths of 772 and 1598 m and commercial hauls (580–600 m) on compact mud bottoms off the south-eastern Sardinian waters (central-western Mediterranean) were carried out. The Sardinian catches did not indicate any particular trend of size-range in relation to depth in both sexes and seem to be sexually dimorphic with females growing almost 9 cm longer than males at maximum lengths. It was a dioeceous and an oviparous deep-sea species. For females and males, six stages of oocyte development, characterizing the different stages of maturity, were identified. Histological examination demonstrated that ovaries of N. melanurum showed a ‘group-synchronous’ pattern, highlighting a type of monocyclic ovary. The species showed a size at first maturity of 53.5 cm and 50.5 cm total length in females and males respectively. The reproductive period appeared to be unique and well defined in both sexes. Their monthly changes of gonadosomatic index and maturation phases of ovaries and testis showed that the species was in a resting period from March to July. Vitellogenesis and spawning began in September and ended in January. Nettastoma melanurum seemed to be a fecund species (8132–18755 eggs).

Shepherd's beaked whale Tasmacetus shepherdi is one of the most poorly known cetaceans, whose diet has created some speculation given that its dentition differs greatly from that of most other beaked whales that are primarily teuthophagous. The few stomachs examined previously have given seemingly conflicting dietary information. In this paper the stomach contents of a freshly stranded adult female on Tristan da Cunha have been examined through identification of trace elements and genetic analysis of soft parts. At least 13 cephalopod and 8 fish species were identified from beaks and otoliths respectively, but only undigested fish remains were present in the stomach and identified genetically as Beryx splendens. Reconstituted masses totaled 8809 g for cephalopods and 17,554 g for fish, with four species (Histioteuthis atlantica, Taningia danae, Ommastrephes bartrami and Pholidoteuthis ‘A’) comprising 78.6% of the cephalopods and one species (B. splendens) comprising 87.4% of the fish eaten. It is concluded that Tasmacetus may alternately exploit fish and cephalopods, depending on the time of day and access to seamount or continental slope areas.

This paper contributes an updated and detailed review of fin whale mortality events in the Adriatic Sea, encompassing four centuries. A total of 17 events, all referring to single animals, were validated through a content review of historical and recent information. Mortality events in the area mostly involved dead animals (N = 12; 70.6%), with 2 whales live-stranded (11.8%) and 3 killed (17.6%). Most records (70.6%) are for the last century, likely due to improved reporting. We provide a detailed description of the previously unpublished killing of an adult male fin whale which occurred in 1960 in the central-western portion of the basin.

This is the first record of a ladyfish (Elops smithi) larva in Uruguay and the southernmost South Atlantic record. We provide morphological–merisitc and environmental information about the larva collected in March 2010 in brackish waters of the Solís Grande estuary. The sampling site was 0.9 m depth, water was warm (21.7 °C), low salinity (12.3) and with high oxygen content (7.7 mg l−1). The larva was very transparent, 31 mm in standard length and had a total of 76 myomeres. The dorsal fin (24 rays) and the anal fin (16 rays) did not overlap. The caudal fin was forked; the pectoral fin without rays and pelvic fin was in an early phase. The swim bladder was inverted U shaped. The half premaxilla had 8 teeth and the half mandible 10 (of similar size and appearance). Pigments were present in the ventral line (from the thorax to anus) and in the middle lateral trunk and caudal peduncle line. These characteristics suggested an early-metamorphic stage of the larva. This species is recorded with low abundances in southern Brazil. The collection of this individual occurred during a period of strong El Niño (2009–2010). These events are associated with warm sea surface temperature anomalies in the south-western Atlantic and northerly winds anomalies in the Brazilian–Uruguayan continental shelf.

Re-examination of Megabalanus azoricus from the Azores revealed previously unknown morphological features. Examination of more exemplars also confirmed the description made by Pilsbry in 1916. Morphological features are herein described (e.g. true tergal spur) and morphometric relations are established for the first time, providing a significant contribution towards the management of this important Azorean seafood resource.

We report for the first time the occurrence of the irregular sea urchin Echinoneus cyclostomus for Puerto Rico. This report increases the known regional distribution range of the species and the number of Puerto Rico shallow water echinoids to seventeen. In addition, we report a new locality for Cassidulus caribaearum, the other echinoid recently recorded for the island.

This study was carried out on fatty acid composition in wild and cultured varieties of two fish species, Epinephelus coioides and Sparidentex hasta. Fresh fish samples were collected from Hormozgan, Iran. After lipid extraction, fatty acids composition was analysed by gas chromatography. Results showed DHA (C22:6n3), EPA (C20:5n3), palmitic acid (C16:0), stearic acid (C18:0), myristic acid (C14:0), oleic acid (C18:1n9c) and palmitoleic acid (C16:1) were important fatty acids in the fish samples. There was low concentrate of linolenic acid (ALA, C18:3n3) in all analysed samples. Cultured fishes were found to contain significantly higher values of SFA, while their wild relative contained higher levels of MUFA followed by PUFA. In the wild fish species among PUFA, DHA were the most abundant followed by EPA. Altogether, EPA was the most abundant followed by DHA in the cultured fish species. Also the ω3/ω6 ratio was significantly higher in wild fishes and it was highest (13.04) in wild E. coioides.

Caprella scaura is thought to come from the western Indian Ocean and was first recorded in the Atlanto-Mediterranean region in the Lagoon of Venice in 1994. Since then the species has rapidly spread throughout the Mediterranean Sea and it has recently been reported in the eastern Atlantic Ocean. The occurrence of C. scaura in two marinas in Lanzarote, Canary Islands, is discussed taking into account the possible pathways of introduction. The most likely vector of introduction is within the hull-fouling community on recreational craft. It may be expected to appear in other marinas within Macaronesia.

A sample of 3393 garfish, Belone belone (Linnaeus, 1761) was captured using a seine net between January 2003 and December 2008, along the eastern Adriatic Sea. The range in total length was 20.8–75.4 cm and in weight was 12.21–639.25 g. Length–length equations for converting size measurements (standard length and fork length to total length (TL)) were linear. In the length–weight relationship, positive allometry was established (b = 3.4818). Age, determined from sagittal otoliths, ranged from 1+ to 8+ years. The estimated von Bertalanffy model growth parameters for garfish were L∞  = 90.3 cm, K = 0.158 year−1, t0  = −0.109. Otolith weight was endorsed as a possible age predictor, as it showed highly exponential correlation with total garfish length and age (Wo  = 0.0012 TL 2.189; Wo  = 0.568t1.486). These findings were used to examine mortality rates and exploitation in order to improve conservation and management of this pelagic species.

The Cortes geoduck (Panopea globosa) has been considered a Gulf of California (GC) endemic but anecdotal and unpublished evidence has suggested its presence in Bahía Magdalena (BM), on the Pacific coast of southern Baja California. Establishing the identity of geoduck clams and their distribution limits is not only of clear biological significance to understand their structural and functional variation, but is also of consequence for their conservation and management, given the multi-million dollar fishery they support in north-west Mexico. We analysed Panopea clams from Mexican populations, including BM, using an integrative approach including genetics, morphometrics, and an ecological niche model. Our genetic results (restriction fragment length polymorphisms of nuclear ribosomal DNA and mtDNA cytochrome c oxidase subunit I sequences) clearly identify BM geoducks as P. globosa, implying a significant geographical range expansion outside of the GC and refuting its status as endemic to the Gulf. On the other hand, clams from BM were phenotypically different (shell significantly higher) from other Mexican P. globosa and Panopea generosa specimens, which may account for the confusion in their morphological identification. The ecological niche model for P. globosa, integrating ecological and distributional data from the GC, revealed a very low probability (<10%) that this species could successfully occupy BM. Our results and those of others suggest that the Cortes geoduck population in BM may be adapted to specific environmental conditions differing from those experienced by conspecifics inside the Gulf and is likely isolated. This is highly relevant for the management plans of Mexican geoducks.

Some crustaceans show variations of their reproductive biology within their geographical distribution, and knowledge about such variations is important for the comprehension of their reproductive adaptations. This study compared two populations of the fiddler crab Uca uruguayensis from two locations on the south-western Atlantic coast: Ubatuba Bay, São Paulo, Brazil and Samborombón Bay, Buenos Aires, Argentina. The population features analysed were the body size variation (carapace width = CW) and the size at the onset of sexual maturity (SOM) in order to test the hypothesis that the size at SOM, should be the same in relative terms (RSOM), independently of the latitudinal position. In the Brazilian population the CW ranged from 4.18 to 11.60 mm for males and 3.90 to 9.80 mm for females, and in the Argentinean population from 3.60 to 14.10 mm for males and 2.85 to 12.00 mm for females. In the Brazilian population the SOM was 7.1 (RSOM = 0.58) and 5.9 mm CW (RSOM = 0.57) for males and females, respectively, and in the Argentinean population it was 7.0 (RSOM = 0.42) and 6.75 mm CW (RSOM = 0.53) for males and females, respectively. This fact is probably related to a great plasticity in the life history features of Uca uruguayensis under different environmental conditions.

Haliclona indistincta has in some respects, a typical reproductive cycle for a marine haplosclerid sponge. We suggest that oocytes originate from archaeocytes and that spermatozoa originate from choanocytes. Oocytes were first seen in November and matured as eggs by May and June. Immature spermatic cysts were identified from February and mature cysts were present in May and June only. Of the individuals surveyed that had reproductive elements present (150/200), reproductive elements from a single sex were reported in over half of the specimens (59%) but there were also many hermaphrodites (41%). Embryos were first seen in June. Larvae were distributed throughout the mesohyl and were released from the end of June to the end of July. Three mobile larval stages and fusing of sibling larvae were observed. Post-settlement stages from early settlement to the development of oscula and excurrent canals are also shown. However, some elements of the larvae (uniform ciliation and no spicules at posterior pole) are not consistent with larvae from this genus.

The distribution and composition of molluscan assemblages of seagrass beds in the Ensenada de O Grove (north-western Spain), are described in this paper. The studied bottoms were mostly muddy and colonized predominantly by Zostera marina L., Z. noltei Hornemann, or by both species. Molluscan fauna was dominated by gastropods and bivalves, in terms of both species richness and abundance. A total of 7641 individuals belonging to 68 taxa was identified. The most abundant species were the gastropods Peringia ulvae, Retusa truncatula and Calyptraea chinensis and the bivalves Abra alba, Loripes lucinalis and Kurtiella bidentata. Cluster and multidimensional scaling analyses based on Bray–Curtis similarity coefficient showed two distinct faunal assemblages. Group A comprised intertidal sites colonized either by Z. noltei or by Z. marina and Z. noltei on muddy sand and sandy mud bottoms and subtidal sites exclusively colonized by Z. marina in the outer part of the inlet on muddy sand with the highest values of species richness and diversity. Group B consisted of sites characterized by low values of species diversity and a species composition typical of a ‘reduced Macoma community’. The sorting coefficient and the combination of gravel, sorting coefficient and carbonates content (BIOENV analyses) and the salinity of bottom water and depth (canonical correspondence analyses) were the most important abiotic variables in explaining the structure of the molluscan assemblage.