Some sea cucumbers species are heavily exploited as bêche-de-mer for the Asian food industry and the global decline of certain highly sought after species has generated an interest in determining the ecological function of those animals within their ecosystem. This study investigated the ecological role of Holothuria scabra, a commercially valuable tropical species closely associated with seagrass beds. Seagrass productivity, seagrass and benthic microalgae (BMA) biomass and organic matter (OM) were measured during two exclusion experiments conducted using in situ cages deployed for two months both in 2003 and 2004. Density of H. scabra was manipulated in caged exclusions (near-zero density, ‘EX’), caged controls (natural densities, ‘CC’) and uncaged controls (natural density, ‘NC’). Seagrass growth was lower when holothurians were excluded (5% in 2003, 12% in 2004). Seagrass biomass decreased in all treatments, but reduction was greater in EX than in controls (18% in 2003, 21% in 2004). Both BMA biomass and OM increased in EX compared to NC/CC (in 2004). From a multivariate perspective, a principal component biplot separated EX from both types of controls in 2004, and multivariate tests based on four attributes supported this separation. These results indicate that seagrass systems may suffer in the absence of holothurians; however, the effect size varied between the two experiments, possibly because experiments were conducted at different times of the year. Nevertheless, our results suggest that holothurian over-fishing could have a negative impact on the productivity of seagrass systems.

Every year, an undetermined number of loggerhead turtles cross the Gibraltar Strait entering and going out of the Mediterranean Sea. An unknown percentage of them strand on the Andalusian beaches, alive or dead, with an unequal distribution along the coast. We found a geographical pattern in the density of strandings, as well as in the proportion of them that were alive and dead. Atlantic areas receive a higher number of strandings, although most of them correspond to dead individuals, especially on the west coast (province of Huelva), whereas on the Mediterranean coast there is less difference between the number of alive and dead turtles stranded. The causes of stranding also presented a spatial segregation along these coasts: net fisheries were concentrated in Huelva, cold stunning was more frequent in Atlantic Cádiz, and debilitated turtle syndrome and longline were biased to the Mediterranean coast. The Atlantic areas might be an important accumulation zone for turtles, but where they endure a high human-induced stress and mortality. In the Mediterranean area, different causes, such as the narrowness of the Alborán basin, the ocean currents, human activity, or the number of turtles crossing, may increase the number of turtles stranding alive on the coast.

This study, carried out from August 2000 to July 2006, began out of the recognition of a special ecological situation, when an aggregation of juvenile green turtles (Chelonia mydas) was found inside the effluent discharge channel of a steel plant located near Vitória, the State of Espírito Santo capital, eastern Brazil. The green turtles were captured through either cast nets or a set net or by hand (one turtle was captured alive on one of the channel banks); after data collection, they were released back into the discharge channel. Information is here reported on the temporal pattern of occurrence, size-classes, residency, presence of tumours and growth rates of tumoured and non-tumoured green turtles in the study area. A total of 640 individual green turtles were captured in the six years; 448 of them were captured just once, and 192 were captured two or more times. Curved carapace length ranged between 25.2 and 77.5 cm. Among the captured green turtles, 59.1% were classified as being in normal body condition and without any tumours, 6.6% were either underweight or emaciated but without any tumours, and 34.4% had tumours, with different levels of the tumour severity score.

Using aquaria containing natural sediment, medium-term burrow development was investigated. After initial construction, and over the first month, relatively little burrow development was observed in terms of the number of openings and tunnels created. After an additional six months, however, there was a significant increase in the number of openings and tunnels constructed. In contrast to what might be expected from the number of openings and tunnels created during this period, a significant proportion of the sediment movement was sub-surface and relatively little sediment expulsion occurred. The concentration of nitrite, ammonia and phosphate in the burrow water was generally greater than that of the surface water, whilst the nitrate and sulphate measurements showed no particular pattern. Only the differences in phosphate concentrations were found to be significantly different. These results were indicative of Calocaris macandreae influencing rates of denitrification. This study also provided further evidence of carnivory and caching behaviour in this species.

The LS5096 h of prawn, Palaemon elegans, was determined at various salinities (0–45 ppt) with the Caspian Sea salt proportion. In addition, growth indices, survival and moulting at salinities 8, 13 and 18 ppt were also studied during four weeks. All the experiments were carried out in the laboratory (24±1°C). The results showed that more than 50% of the prawns survived at 1 to 30 ppt salinity range, while above and below this range, less than 50% survived within 24 hours. No significant differences (*P > 0.05) in growth parameters such as carapace length (CL) increase, specific growth rate (SGR) and also in survival and moulting rates were observed in prawns reared in salinities 8, 13 and 18 ppt. Mean intermoult period in each salinity was 8.12 ± 3.07, 8.61 ± 2.96 and 8.92 ± 3.47 days, respectively. Salinity 8–18 ppt was found to be the optimum range for P. elegans in the studied length range (CL, 6–9 mm).

Age and growth of the clam Chamelea gallina from dredged, non-dredged and closed areas of the Turkish Black Sea coast were estimated. Von Bertalanffy growth curves were fitted for each sampling site; asymptotic length (L∞) values ranged between 25.995 and 28.883 mm and the growth coefficient (K) from 0.164 to 0.217 per year. Results indicate growth rates were significantly reduced in the far eastern commercial populations compared with those in western populations. According to our results presented here it can be concluded that C. gallina at closed area does not grow as fast as non-dredged stock and this is because of the shortness of closure season. Nevertheless we suggest that fallowing is the major precaution for the recovery of C. gallina stocks in the Black Sea.

Hemigrapsus crenulatus is an abundant and frequent decapod crustacean inhabiting estuarine environments, where it must tolerate large shifts in salinity. The present study evaluates the effect of salinity (5, 13, 21 and 30 psu) on the adult physiological processes related to the energy balance. The growth potential (SFG) and the respired oxygen:excreted nitrogen ratio were used as indices of stress. Ingestion, excretion and respiration rates showed a significant dependence on salinity, being higher at low salinities. The assimilation efficiency remained constant along the studied salinity gradient. The assimilation and ingestion rates were inversely related with the salinity. Given this scenario, the growth potential remained constant within the studied salinity gradient, as did the oxygen:nitrogen ratio. The results suggest that the increased energy losses at low salinity due to respiration and excretion are compensated by an increment in the ingestion rate, contributing to the success of H. crenulatus in dynamic habitats such as estuaries.

Precopulatory mate guarding behaviour of the skeleton shrimp Caprella penantis is described. Moreover, the effects of body size, ownership and sex-ratio on mate guarding were examined experimentally in the laboratory. In the field population, the operational sex-ratio was male-biased. Guarding pairs, which were collected from the field, continued guarding for an average of 350 minutes in the laboratory, indicating that the normal guarding duration is approximately 10 hours. In this species, two guarding types were found: Type O and Type I-like. In Type O guarding, the male would fold the female into a horseshoe shape, whilst the male held the female parallel to him in Type I-like guarding. In the laboratory experiments, male body size was the most important factor affecting competition for a receptive female; ownership was the secondary factor. Guarding duration was prolonged when the sex-ratio was male-biased. Thus, the precopulatory mate guarding behaviour of C. penantis is influenced by several factors, such as body size, ownership and sex-ratio.

The reproductive biology of the commercial seabait polychaete species Perinereis nuntia brevicirris, Lumbrineris funchalensis and Halla parthenopeia was investigated from samples obtained from the Suez Canal, Egypt, to determine sex-ratio, reproductive maturity stages, spawning season, and fecundity. Samples were collected monthly from January 2002 to February 2003. The results of sex-ratio indicated that males of the three studied worms outnumbered females through the whole study period. Based upon histological features of the coelomic contents, four maturity stages were described in females of P. nuntia brevicirris, three stages were described for females of L. funchalensis and three stages for females of H. parthenopeia. The spawning season of P. nuntia brevicirris was found to take place during spring and L. funchalensis does not have a defined breeding season, while H. parthenopeia has two reproductive periods, one in May and the second in November and lasted to January. Fecundity was estimated by counting the number of oocytes per each female—it showed that P. nuntia brevicirris is more fecund (mean = 208.358 ±2080 oocyte/female) than L. fanchalensis and H. parthenopeia (mean = 2660 ±654 and 142,068 ±2005 oocyte/female respectively). This study is the first to document aspects of the reproductive biology of the highly commercial polychaetes in the Suez Canal and adds to our knowledge for understanding their reproductive patterns and strategies.

Colonial invertebrates often mix sexual and asexual methods of propagation, and a comprehensive understanding of both is required for life history study. The asexual cloning of new colonies in cupuladriid bryozoans is much better studied than the formation of new colonies by sexual reproduction. As such, the relative investments of sexual and asexual modes of propagation remain uncertain. This preliminary study explores patterns of embryonic brooding as a measure of investment into sexual reproduction. We conduct a survey of quantity and arrangement of embryos in tropical eastern Pacific cupuladriid colonies and compare this to the frequency of cloning. Species populations show considerable variation in embryonic brooding. Patterns of brooding, both across and within species strongly support the hypothesis that as cloning increases, investment into sexual reproduction decreases. We find preliminary evidence that individual cupuladriid colonies that propagate sexually may senesce like solitary organisms, while species that regularly clone only appear to experience senescence at the level of the zooid.

Fatty acids composition of two marine copepods, Acartia tonsa and Centropages brachiatus, and lipid profiles of natural food assemblages were studied during the austral summer 2006 at three upwelling sites in the coastal upwelling zone off Chile, along with oceanographic conditions. Fatty acids of food supply were assessed for the picoplankton, nanoplankton and microplankton size fractions. There were marked differences in upwelling conditions among locations, as well as in their food supply in terms of quantity and quality. Differences in fatty acid composition were also found, both among food assemblages and between copepod species. Essential polyunsaturated fatty acids (PUFA; linoleic acid) and monounsaturated fatty acids (MUFA; oleic acid) dominated the picoplankton and nanoplankton size fractions of food, and they were highly represented in both species of copepods, indicating these size fractions were the major contributors to their diet. These fatty acids can thus be considered as useful trophic markers for copepods. Variation in lipid profiles between species depended on sampling sites, whereas differences in lipid composition among sampling sites were attributed to distinct upwelling conditions, which drive the changes in food quality, such that trophic response is highly dependent on food offer. Variation in fatty acids compositions of copepods may thus act as an indicator of upwelling variability. Our findings suggest that lipid transfer from primary producers to primary consumers can have a crucial role for carbon cycling in the marine food web, and that picoplankton and nanoplankton fractions are the key items of copepod diet in this upwelling system.

The prevalence and infestation intensities of Octolasmis lowei in the branchial chambers of Libinia spinosa were evaluated according to the host's sex, size, and moult condition. Epibionts were classified as cyprid larvae, non-ovigerous or ovigerous according to their developmental stage. A median intensity of infestation of 21 epibionts/host was found (range = 1–644; Q3 = 81). Epibiont prevalence values (88%) were higher on ovigerous female hosts than on males (55%) or on non-ovigerous females (31%). Intensity of infestation was positively correlated with host size in both sexes for non-ovigerous and ovigerous epibionts. No preference between host sex by cyprid larvae was observed, nor any correlation between cyprid abundance and host size. Cyprid larvae abundance was positively correlated with settled epibionts on both host sexes. The duration of the intermoult phase was the main factor linked to the establishment of sessile epibionts. These observations are important in relation to crabs that have a terminal moult, because these animals cannot eliminate their epibionts in future moults, thus increasing the importance of density-dependent mechanisms on epibiont establishment; in that way, prevalence of infestation alone can underestimate the real impact of infestation on the host's life cycle.

The present study describes the reproductive biology, population structure and life history traits of the abundant intertidal crab Xantho poressa. Between March 2007 and April 2008, a total of 1918 individuals were collected in Corrales de Rota (south-western Spain), a human-modified intertidal habitat characterized by an artificial high complexity. Suitable refuges for crabs (cobbles and boulders) are very abundant in this area and density (maximum of 50 ind*m−2) was directly related with the area covered by these stones. In spring and summer, size–frequency distributions showed a polymodal pattern with seasonal variations related to the incorporation of juveniles to the adult population. Newly settled juveniles were not found in the Corrales suggesting an ontogenetic migration from a distant recruitment habitat. The annual reproductive cycle was seasonal and successive peaks in the abundance of ovigerous females were observed in late spring and summer. Females probably produced multiple broods during a long intermoult period. The gonadosomatic index had a cyclic pattern of variation with peaks two weeks prior to those of ovigerous females; it was lower during the non-reproductive season. The hepatosomatic index was high during spring, decreased during summer and increased gradually at the end of the reproductive season. There was a monthly cycle of larval release resulting from a combination of a cyclic and synchronic ovarian maturity, oviposition and incubation; hatching took place during neap tides when the moon was at last quarter. The adaptive significance of the rhythmic reproduction and hatching observed may not be explained by the predator avoidance hypotheses. The overall sex-ratio did not differ from 1:1 but one male and several females coexist under a stone, indicating a female biased operative sex-ratio. The combination of a complex habitat, its use, and a strong sexual dimorphism suggest a refuge–defence polygenic mating system. The survival and fitness of X. poressa in the Corrales de Rota are probably enhanced by the availability of shelter, a consequence of a highly complex habitat, and probably, of human activity.

Field investigations on Perna perna were carried out in 1999 in an unpolluted site (Cap Ghir) and a wastewater-polluted site (Anza) to determine the contents of glycogen, lipids and proteins in mussel samples collected every month. Sample analyses were made using the entire soft masses of male and female mussels or their gonads only. Compared to unpolluted P. perna, the glycogen and lipid concentrations found in polluted mussels showed significantly quantitative variations throughout the year; in contrast, insignificant differences were only found for protein concentrations. Female gonads contained higher rates of lipids than male ones, whereas protein contents were similar. In contrast, in entire mussels, females were richer than males, whatever the biochemical parameter considered. Apart from protein rates in December, most of highest concentrations were noted from October to November. Contrary to unpolluted mussels (of which storage components were constituted by glycogen and lipids), a different reserve strategy, mainly based on the use of lipids, followed by that of proteins would exist in the P. perna from the polluted bed.

Eggs of Melongena melongena develop inside round, flat egg capsules which contain a gelatinous intracapsular fluid. To determine if this gel represents a nutritional source for the developing embryos, we measured the amount of proteins of the embryos throughout their development from the egg to the hatching stage as well as the protein content of the intracapsular liquid at the same stages of development. Egg capsules of M. melongena were collected at Golfete de Cuare, Venezuela between 1–2 m depth. Uncleaved eggs measured 352–480 μm and contained 8–15 μg of protein/egg. This amount of protein was not significantly different at the trochophore, veliger and pediveliger stages, however, it decreased significantly at the hatching stage to 6 μg/hatchling. About 95–98% of the eggs develop to the hatching stage, the remaining 2–5% remain intact in the egg capsule. Hatching takes place as a pediveliger measuring around 720 μm in shell length. The protein concentration of the intracapsular liquid was 0.18 μg/μl at the egg stage and it reached 0.13 μg/μl at the prehatching stage; however, the total amount of protein in the intracapsular fluid was not significantly different throughout the development from one stage to another. Results indicate that embryos of M. melongena use neither the intracapsular liquid as an extraembryonic food source, nor nurse eggs.

At Burgers' Ocean 7 male and 3 female blue spotted stingrays, Dasyatis kuhlii were born over a period of 4.5 years. This paper describes the experiences of the captive breeding results of this species. The first two young died within 2 days of birth. One of them had an internal yolk sac, which may feed the young in the first few days. The other eight animals started to feed after 4 to 9 days on a variety of food types. Birth size of the young increased with increasing age of the parents. Mating occurred directly after parturition, so no seasonality could be defined. Gestation length ranged between 138 and 169 days, with a mean of 144.9±9.0 days (N = 11). Litter size was one, possibly caused by only one active ovarium. Sexual maturity of the two parent animals is approximately 3.5 years. The average feeding rations for the adults ranged between 10.1% BW week−1 (131 kcal kg BW−1 week−1) and 11.3% BW week−1 (172 kcal kg BW−1 week−1), with a feeding frequency of 4 times per week. The relationship between body weight (BW) and wingspan (WS) is given as BW = 3.6 × 10−5* WS2.940 (R2 = 0.9645; N = 45).

Photo-grammetric techniques developed for measuring body length and small scale movement patterns of cetaceans were applied to surface swimming basking sharks off the west coast of Scotland. These methods removed the need for close approaches, reducing the likelihood of disturbing the focal animal. Average swimming speed was calculated from the total path length between shark locations measured at approximately one minute intervals. These average speeds varied from 0.49 to 0.73 ms−1 for tracks of between 30 and 170 minutes' duration. Body length measurements ranged between 2.35 and 6.43 m. For ten sharks where body length and swimming speed were measured there was a significant correlation between body length (L) and swimming speed (V) expressed as V = 0.36L033.

Two species of the bobtail squid Heteroteuthis are reported from the Atlantic Ocean, H. dispar in the North Atlantic Ocean and H. dagamensis in the South Atlantic Ocean. In total 58 individuals were examined, 23 belonging to the species Heteroteuthis dispar and 35 belonging to the species H. dagamensis. All specimens were captured during the Walther Herwig Expeditions 1966, 1968, 1976 and 1982. A full description of both sexes of H. dispar and H. dagamensis is provided. These two species can only be distinguished by means of the male's enlarged suckers on arm pair III. Females are not useful for taxonomic identifications and are morphologically identical in both species. The results do not support the definition of subgenera in this genus. This is the first report for Heteroteuthis dagamensis in the South-West Atlantic Ocean.

Two new species of free-living marine nematodes, Daptonema longiapophysis sp. nov. and Cobbia sinica sp. nov. from the Yellow Sea, China are described and illustrated. Daptonema longiapophysis sp. nov. is characterized by spicules with a projection on the ventral and dorsal side respectively and the length of the gubernacular apophysis longer than the length of spicules. Cobbia sinica sp. nov. is characterized by one big dorsal tooth, long conico-cylindrical tail and gubernaculum with a small dorsal apophysis.

A new species of copepod, Paracalanus arabiensis sp. nov. collected from Mandovi and Zuari estuaries, Goa, central west coast of India, is described. It differs from its congeners mainly in the structure of leg 5, with a row of six teeth along the edge of inner terminal spine resulting in a serrated margin and two small, stiff spines of equal length protrude in between the terminal spines.