The interest in the knowledge of the ecology of soft-sediment communities is increasing due to the importance that these environments pose to ecologists and environmentalists. However, the ecology of Argentinean sandy beaches is almost unknown, in spite of being relatively common landscapes. In this work we describe and compare the macroinfaunal assemblages in the two largest sandy beaches within the Monte León National Park, the first marine-coastal park of Argentina. Macrobenthic samples were collected and environmental descriptions were performed by quantifying and comparing the organic matter content, grain size distribution and depth of the substratum available for macroinfaunal colonization. Results show that polychaetes and crustaceans are the dominant taxa and that the two beaches differ in the physicochemical characteristics, suggesting that a relation between the benthic fauna and physicochemical factors exists. Although they appeared similar at the landscape scale in preliminary visual surveys, the geomorphological differences between habitats are likely to drive strong differences in the structure of the macroinfaunal assemblages. The monitoring of visible landscape features is likely to undermine the efficiency of protection and managing strategies if not complemented by geomorphological and ecological surveys of less visible ecosystem variables.

The recruitment of subtidal macrofouling organisms was studied in the Patagonian harbour of Comodoro Rivadavia (Argentina, 45°51′35″S 67°27′23″W). Changes in coverage and density were analysed in the central 100 cm2 of upper and lower surfaces which were replaced monthly from January to December 2004. The fouling assemblage consisted of algae, spirorbid polychaetes, compound ascidians, hydrozoans, bryozoans and egg masses spawned by the small fish Helcogrammoides cunninghami. Monthly changes in richness and diversity of taxa on upper and lower surfaces were significantly correlated with sea surface temperature. Fouling assemblage structure differed significantly between upper and lower surfaces. Filamentous algae were dominant on upper surfaces, while filter-feeding invertebrates were more abundant on the lower surfaces of the experimental panels. The density of the spirorbid Romanchella scoresbyi was two orders of magnitude higher on lower than on upper surfaces. Its recruitment began in late winter, reaching maximum values in spring.

The spatial distribution of Farfantepenaeus shrimp was analysed in the Laguna Madre of Tamaulipas, Mexico. Sampling was carried out on submerged aquatic vegetation (SAV) habitats at five sites located along the coastal lagoon. Two nocturnal surveys were conducted during winter in 2005 (January–February), collecting a total of 3268 shrimp individuals. SAV beds were composed of a mixture of drift algae (mainly Digenia simplex), attached algae (mainly Penicillus capitatus and Udotea occidentalis) and seagrass (mainly Halodule wrightii). Farfantepenaeus aztecus was more abundant (39.5%) than F. duorarum (36.8%), and the remaining 23.7% corresponding to small unidentified Farfantepenaeus spp. were classified as recruits. Abundance of F. aztecus was significantly higher at sites 2 and 4, whereas F. duorarum did not show significant distribution differences along the Laguna Madre. Recruits, juveniles and total shrimp tended to decrease significantly at the northern part of the lagoon (site 1), where substrate was dominated by drifting algae and seagrasses were scarce or absent. The abundance of shrimp was positively related to seagrass biomass and/or water temperature, whereas there was a negligible or negative relationship with algal biomass. With the exception of subadults, a significant positive linear relationship between seagrass and shrimp abundance was fitted, indicating an increase in number of individuals of both species with increasing seagrass biomass. This suggests that seagrass is the most important component of SAV beds influencing the abundance of F. aztecus and F. duorarum along this hypersaline coastal lagoon.

The aim of this study was to compare the population structure of the invasive bivalve Isognomon bicolor in three different areas on the coast of Rio de Janeiro State and to verify its temporal variation. All the areas presented high densities, reaching more than 1000 live individuals per 100 cm2. The number of dead individuals and recruits was higher in Ilha do Brandão (Angra dos Reis) than in the other areas. The individuals sampled at Praia Vermelha (Rio de Janeiro) presented the highest maximum and mean sizes, compared to those found at Ilha do Brandão. In this area, vermetid molluscs are dominant and build a complex reef structure where only a few individuals of I. bicolor can really grow.

Congrids inhabit the warm and temperate seas of the world, from the coastline to the slope of various continents. Many of its species are much valued by commercial and artisan fishing; nevertheless, at world level, there is great ignorance about the life cycle of the members of this genus. Some species of the genus, such as those from the North Atlantic, appear to be semelparous, for they cease feeding, decalcify, loose their teeth and migrate to deep waters to spawn. Specimens of the southern conger eel Conger orbignianus were examined for the purpose of learning about their biology in waters of the western South Atlantic. Histological sections were analysed from ovaries of coastal conger specimens from the North Argentina coastal littoral, the Argentine Sea deep waters, and the giant congers from southern Brazil. Two oocitary generations have been observed in coastal females typical of total spawners, with a previtellogenetic batch that does not reach maturity, and a vitellogenetic batch that does it together with its size, completely surrounded by adipose tissue. The ovaries of fish captured in deep waters occupied the whole abdominal cavity, with scarce adipose tissue and degraded body. The giant congers from southern Brazil were captured in very deep waters, healthy, with few atretic oocytes and abundant adipose tissue. Evidence of semelparity was found in the southern conger eel; the asistosis stage, the body degradation during the reproductive migration and gigantism might be common attributes in other species of the genus.

Blue sharks (Prionace glauca) and oilfish (Ruvettus pretiosus) are frequently caught incidentally in the swordfish surface drifting longline fishery of the eastern Mediterranean Sea. An information theoretic generalized additive model approach, modelling separately: (1) the probability of making a catch; and (2) the positive catch rates, suggested the presence of intra-annual variations in their abundance and revealed interesting associations with some environmental features. Blue sharks were more frequently encountered during late summer in cool water masses. However, the likelihood of making a larger catch peaked in warmer waters through late spring in the vicinity of land. Occurrences of blue sharks were more frequent to the south-west (Ionian Sea), while positive catch rates were higher in the eastern-most regions (Levantine). Oilfish occurrences, as well as catch rates, were always above average to the east. Intra-annual variation was analogous to that of blue sharks. The species showed a preference for cooler water bodies and its distribution was strongly dictated by the lunar cycle. Annual time series showed a decreasing trend of blue sharks abundance. Catch rates for both species depended on fishing gear configuration. Deeper settings (>20 m), more resilient lines and use of fish attractant light-sticks increased the probability of capturing a fish.

Foraging activity of roving herbivorous reef fish (RHs) from families Acanthuridae (surgeonfish; three species) and Scaridae (parrotfish; five species), and its relationship to resource availability and interference competition, was studied in the largest South Atlantic Reef complex (Abrolhos Bank, eastern Brazil). Observations were undertaken at four sites differing in resource availability and competitors' abundance (i.e. RHs and territorial herbivores from genus Stegastes). Turf algae (TA) were selected by most species in most sites, while other food items were generally avoided. Surgeonfish had higher feeding rates than parrotfish, the former grazing more frequently on fleshy algae (FA) and the latter on crustose calcareous algae (CCA). Both surgeonfish and parrotfish interacted agonistically most frequently with damselfish, followed by confamilial interactions. Despite these consistent patterns, feeding rates, food selection and frequency of agonistic interactions differed significantly between sites for most species. Bite rates on CCA and FA were disproportionally higher in sites where such items were more available, leading to significant spatial variation in grazing selectivity (i.e. positive rather than negative selection of CCA and ‘lower avoidance’ of FA). Although agonistic interactions were more frequent at sites where herbivorous fish (both roving and territorial) were most abundant, there was no clear relationship between interference competition and foraging patterns. These results indicate that the scarcity of other food may induce RHs to consume the dominant resources. They also support the hypotheses that RHs are unable to clear large tracts of reef surface of FA once these have proliferated, and that territorial herbivores do not limit the access of RHs to particular resources.

In order to understand how marine ecosystems function, it is essential to study the trophic interactions among the community members, particularly from poorly known regions. In this study, the feeding ecology and diet of conger eels, Conger conger, an abundant fish species with commercial interest, was examined in the north-east Atlantic, off Algarve (southern Portugal) between May 2005 and August 2006. The diet was characterized by species composition, size and mass of prey. Conger eels are opportunistic feeders, cannibalistic, feeding on benthopelagic/pelagic prey (67% by mass and 71% by number) but also benthic prey (32% by mass and 29% by number). Fish (67.8±4.7% in mass) are the main prey of conger eels, followed by cephalopods (16.5±3.8%) and crustaceans (15.6±3.7%). The most numerous (identifiable) fish consumed were Capros aper, occurring in 90% of the stomach samples that contained food and representing 1.4% in mass, and Scomber japonicus, the most important fish in mass (21.1%), which occurred in 4.2% of the stomach samples that contained food. The present study shows that octopodids can play a more important role in the diet of conger eels than previously thought. Of the species preyed upon by conger eels, six species (21% of the total prey taxa) are caught commercially (Trachurus trachurus, Scomber japonicus, Micromesistius poutassou, Helicolenus dactylopterus and Conger conger) by local fisheries. As discards by local trawl and longline fisheries do not correspond with the diet of C. conger, it is likely that most prey of C. conger in rocky areas were caught actively in that study region.

The stage of development of the gametes of both male and female honeycomb worms Sabellaria alveolata (L.) was examined, using histology, over a 14-month period. Samples came from Howes Strand and Garrettstown, County Cork in south-west Ireland. A clear cycle of both male and female gametogenesis was evident, with a distinct peak in the summer (June–September) when the majority of them were ripe. During October–January a small proportion of males contained abundant spermatozoa, but no mature oocytes were found. Over the whole sampling period the ratio of males:females was 1.4:1. Further south in Roches de la Fosse in France at the centre of its range, two spawnings and an even sex-ratio have been reported.

The population density, annual gametogenic cycle, and size at sexual maturity of two vermetid species, Eualetes tulipa (invasive) and Dendropoma corrodens was studied in the southern Caribbean at the Planta Centro power plant intake channel and at Punta Mayorquina, Morrocoy National Park, respectively. Minimal size of mature females of E. tulipa and D. corrodens was 5.0 and 0.7 cm in body length respectively. The gonad represented between 44 to 47% of total body length, while it represented between 15 to 18% of total body volume (for both males and females). Gonad volume was significantly related to total body volume. A significant quadratic relationship between the number of capsules and female body volume was obtained for E. tulipa, indicating that females measuring 6–10 cm in body length are those that have the highest number of egg capsules. Females larger than 11 cm have a lower fecundity in terms of brooded capsules. Gonad sections of males and females of both species showed that several gametogenesis stages are simultaneous within the same individual. In the female, germ cells, oogoniums and primary oocytes with yolk granules were observed simultaneously. In the male, the spermatogonium, primary and secondary spermatocytes, spermatids and sperm cells were also observed within one gonad. The same pattern was observed throughout the year, showing no maturation/resting period or annual cycle. The area covered by D. corrodens was about 700 m2 with a mean density of 13,000 ind/m2. The area covered by the invasive E. tulipa was at least about 1000 m2, with a density of 27,000 to 29,000 ind/m2 in the first 3 m of depth. A follow up of the E. tulipa population showed that its density is increasing in time and has doubled in 20 years. This population increment could be related to an increase in organic suspended matter as evidenced in the region.

The wide-eyed flounder Bothus podas podas is a small fish that belongs to the Bothidae family. This species is a demersal fish inhabiting sandy and muddy bottoms where it lives buried in the sand. In the Gulf of Gabès (Tunisia), B. podas podas is an uncommon fish caught in small quantities by trawlers, between depths of 20 and 50 m. There are very few complete studies of the biology of this fish in the Mediterranean Sea. Even in Tunisia, the biology of B. podas podas is unknown. In addition, it has been noticed that during the last few years, despite having weak commercial value, this fish has attracted the fishermen's attention of the region after the observed reduction in the flat fish stocks, particularly the Egyptian sole Solea aegyptiaca. The aim of this work was to study the reproduction of B. podas podas and determine the sex-ratio, the sexual cycle, the spawning period and the first sexual maturity. The data for this work was collected during the period of May 2004 until September 2005. In general, this study shows that the proportion of sexes is in favour of females and permits us to analyse the sex-ratio variations according to the size and age of the fish. It also seems that males grow faster than females. The monthly following of the gonad somatic index (GSI), the liver somatic index (LSI) and the condition factor (K) enabled us to determine that the period of maturation occurs from May to August, to define the spawning period from August to November and to deduce that B. podas podas uses the lipid reserves accumulated in the liver to develop its gonads. Concerning the first sexual maturity it was noted that the main size related to 25%, 50% and 75% of matured individuals were respectively for males: 19.68 cm, 21 cm and 22.34 cm and for females: 18.87 cm, 20.4 cm and 21.93 cm. The coefficients of the logistic function were for males: a = 0.827, b = 17.38 and for females: a = 0.718, b = 14.65.

The relative importance of parental diet/population and larval diet were examined on egg, growth, morphology and biochemistry of Sclerasterias mollis larvae. Adult S. mollis were fed one cockle (Austrovenus stutchburyi) per two animals each week, as a low diet, or two cockles per animal each week, as a high diet. The experiment was run for one year. In addition, two field populations (Otago inshore and offshore) with dissimilar nutritional status (based on the gonad index) were selected. Otago inshore starfish had higher gonad indices and assumed to have better nutritional status. The low and high diet laboratory starfish produced eggs with similar characteristics. Eggs from the low diet laboratory parents had the highest carbohydrate concentration. The eggs from the field parents had higher fertilization rate and lower carbohydrate concentration than eggs from the laboratory parents. The Otago inshore starfish had smaller eggs with a lower carbohydrate concentration than the starfish from Otago offshore. Parents from the laboratory or the field had significant effects on larval growth, morphological phenotypic plasticity (measured by the body length relative to the body width) and development rate. Larvae from Otago offshore parents had highest growth and morphological phenotypic plasticity. Larvae from the low diet laboratory parents and those from Otago inshore had the highest development rate. Larvae from low diet laboratory parents had the highest carbohydrate concentration. Neither the parents nor the larval diet had a significant effect on larval mortality. A higher concentration planktonic diet resulted in higher growth, morphological phenotypic plasticity and development rate. Parents were however more important than larval diet on growth and phenotypic plasticity of the larvae. This study showed that parental nutrition has an important effect on growth, morphological phenotypic plasticity and body composition of S. mollis larvae. The nutritional status of the parents does not influence the larvae through a change in the egg size, protein, lipid, carbohydrate and energy content.

Ontogenetic shifts in habitat use and diet are ubiquitous in nature and usually have profound consequences for the ecology and evolution of the species. In the case of species with strong interactions within their communities, such as keystone predators, understanding this kind of size-related change is critical to understand variation and connectivity among spatially distinct habitats of coastal communities. Yet the ecology of early life stages of marine benthic invertebrates, particularly asteroids, is poorly understood. Here we describe the results of surveys to characterize the habitat and quantify the abundance and diet of recruits of the sun star Heliaster helianthus, a keystone predator at rocky intertidal sites in central Chile. Our results support the existence of size-related, ontogenetic changes in habitat use and diet of this species. Recruits occupy boulders and crevices in the high or mid-high intertidal zones of wave-protected habitats and as they grow they move down towards lower tidal levels. Adults are characteristically found in the low intertidal zone of wave exposed and semi-exposed habitats. These changes in habitat use are accompanied by changes in diet composition and particularly by a broadening of the prey species incorporated in the diet. Since early stages of Heliaster appear to be most sensitive to predation and abiotic stress and since adults are such important predators in wave exposed rocky shores, knowledge of the basic ecology of early stages of this species is critical to fully understand the dynamics of intertidal communities.

In this paper we analysed size and shape differences of body (mantle and fins) and inferior beak of the squid Illex argentinus from two Patagonian inner-shelf spawning groups. A new method was developed to reconstruct three-dimensional coordinates based on the 2-D projection of the beak on a plane. Shape of the beak did not vary between groups, sexes and maturity condition of individuals. Also, no beak shape changes were observed through the ontogeny. In contrast, as larger and heavier squids were considered in shape analysis, body widened near the fin insertion, and fin area increased. Our results suggest that shape adaptations of I. argentinus through the ontogeny reflect modifications to optimize swimming performance rather than to increase gamete holding capacity.

As well as acting as a neurotransmitter, serotonin is also involved in morphogenetic signalling during crucial phases of many developmental and regenerative processes such as cleavage, migration and differentiation. Echinoderms display nerve-dependent regenerative phenomena and serotonin is one of the main neural regulatory factors that have been identified in them. The present work was designed to investigate the broad-spectrum involvement of this molecule in echinoderm regeneration, focusing on arm regeneration in the crinoid Antedon mediterranea. We carried out specific in vivo exposure experiments to selected anti-serotonergic drugs (a synthesis inhibitor: parachlorophenylalanine and a receptor antagonist: methiothepin) and explored their possible effects on arm regeneration. Drug exposure appeared to affect regeneration, causing a general delay of regenerative growth and several histological anomalies mainly in the muscles of the stump. In addition, exposure to the antagonist produced a marked reduction of cell proliferation in both the regenerate and the stump. Our results provide further evidence that serotonin has wider functions than those related to interneuronal communication and that it may be a critical signalling molecule in the main processes of regeneration such as proliferation, morphogenesis and differentiation.

Age determination using quantification of in situ neurolipofuscin has been an useful and reliable tool to understand population dynamics of crustaceans. In the present investigation, in situ neurolipofuscin was quantified in the medulla terminalis of eyestalks (cluster A cell mass, MT-A), and in the olfactory lobe cell mass 10 (OLCM-10) of the supra-oesophageal ganglion of unknown age blue crabs (Callinectes sapidus) caught in the wild. No significant difference in neurolipofuscin quantity was found between right and left MT-A and between right and left OLCM-10. Comparison between MT-A and OLCM-10 resulted in a weaker correlation. Average neurolipofuscin was 0.353±0.038% vol. and 0.896±0.105% vol. in MT-A and OLCM-10, respectively. Size explained 23% of the variation of neurolipofuscin loading in OLCM-10. No significant relationship was found between size and MT-A neurolipofuscin content. It can be concluded that both structures are suitable for the quantification of neurolipofuscin, and they have the potential for age determination for C. sapidus.

This study was conducted to clarify the seasonal variation of the chemical composition of the Tunisian Sardinella aurita with a focus on the total lipid content. The chemical composition showed a large fluctuation over years in response to various factors. For the entire fish, lipid content was lower in July (2.50%), but higher in November (10.25%). It varies with seasons in inverse proportion to water content. Interestingly, it was found that red muscle have much higher lipid content than white muscle and the entire fish body. The major fatty acids in S. aurita lipids were palmitic acid, palmitoleic acid, eicosapentaenoic acid, docosahexaenoic acid and myristic acid. Palmitic acid comprised the main proportion (23.9%). The high amounts of saturated and monounsaturated fatty acids in the screened species are almost in agreement with other studies. Moreover, the percentage of omega-3 fatty acids (25%) was very similar to that in oil production commercial fish.

A new species of the marine gastrotrich taxon Thaumastoderma is described. A single specimen of this species, Thaumastoderma antarctica sp. nov., was extracted from silty sediment sampled at one station of the Andeep-1 cruise, about 150 km to the north of the South Shetland Islands (Drake Passage, South Atlantic Ocean). This paper provides the first record of this genus from the deep sea and the second description of a macrodasyid gastrotrich living in an abyssal habitat. The new species is characterized by several apomorphic features, among them a caudal pair of strongly elongated dorsal cirrata tubes. A phylogenetic analysis of the genus Thaumastoderma reveals that Th. antarctica is closely related to Th. coronarium and Th. appendiculatum. Furthermore, the analysis offers an evolutionary scenario and a hypothesis for the internal phylogeny of this taxon while supporting its monophyly. It is the first time a cladistic analysis has been conducted for a delimited group of gastrotrichs, i.e. for all known members of a genus.

Three species of Boccardia (B. polybranchia, B. pseudonatrix and B. proboscidea) were associated with mollusc shells on the south and south-east coasts of South Africa. Boccardia polybranchia was widely distributed along the coast and falls within the known distribution range of this species. Comparisons with material from other, international, locations showed that some specimens have been misidentified. No characters could be found to characterize distinct species for different regions within the range of B. polybranchia, as currently recognized. Boccardia pseudonatrix was found only at the most eastern site, increasing its known distribution range. Boccardia proboscidea, a non-indigenous species, was found only on abalone farms and was most abundant in the west.

A new species of Conidae is described from Brazilian waters. Mitromorpha santosi sp. nov. from the Continental Slope off the state of Rio Grande do Norte (north-east Brazil: 04°50′60″–04°51′40″s, 35°06′01″–35°06′46″W) is compared with M. biplicata (western Atlantic), M. usta (eastern Atlantic), M. dalli (north-eastern Atlantic), M. popeae (West Indies), M. undulate (West Indies) and two unnamed Brazilian species being diagnosed as possessing strong axial ribs, second spiral cord on the body whorl more pronounced and yellowish-brown spiral bands. In addition, a lectotype for Mitromorpha undulata, is designated herein.