The identification of key resource users and patterns of depletion alongside ecological data are presented for a small-scale traditional invertebrate fishery in south-western Madagascar. Men, women and children undertake the fishery in the Anakao region at different phases of the tide and for different purposes. Invertebrate harvest data from June to September 2000 estimated that more than 34 taxa were caught and were dominated by holothurians destined for export and molluscs for local consumption. Crustacea formed a small component of the fishery despite a high diversity and abundance of many potentially edible species. Although there was slight spatial variation in number of species caught and their relative importance to the fishery, Chicoreus ramosus, Fasciolaria trapezium and Octopus vulgaris were generally most heavily targeted and were amongst the most abundant in the catch. There were several indications of over-exploitation of invertebrate stocks, including the absence of many large bodied species, low abundance of high yield species, greater catch effort needed for high yield taxa, and higher diversity of targeted species (including many low yield taxa) at sites of higher human habitation.

The commensal (and possibly mutualistic) symbiosis between the marine chironomid, Halocladius variabilis, and brown algal epiphytes of Fucus vesiculosus and Ascophyllum nodosum is described for the first time from Europe, based on field studies from the White Sea, Russia. While the primary host, Elachista fucicola, and the secondary host, A. nodosum, are the same as in eastern Canada where the symbiosis was first described, White Sea populations have a wider range of primary hosts that include Pylaiella littoralis and Dictyosiphon foeniculaceus. About 64% of E. fucicola thalli on A. nodosum in the low intertidal zone were colonized. Significantly lower frequencies were found on E. fucicola when the latter was epiphytic on F. vesiculosus at the same tidal height or on either secondary host when they were in the subtidal zone. For a given tidal height, or secondary host, frequency of H. variabilis was reduced on P. littoralis and further reduced on D. foeniculaceus. We suggest that subtidal populations are colonized by dispersal of larvae from the intertidal zone on to suitable substrata, and that there is limited potential for these individuals to reach the intertidal zone as adults for reproduction.

The patterns of mitochondrial genetic diversity were studied in Chelonibia caretta, commensal barnacles of the endangered hawksbill sea turtle Eretmochelys imbricata from Mona Island of Puerto Rico. Two mitochondrial genes were sequenced: the large subunit of ribosomal RNA (16S rRNA) and the cytochrome oxidase subunit I (COI). Haplotypic diversity (h) for 16S (N = 34) and COI (N = 26) varied from 0.763 to 0.468, respectively. The nucleotide diversity (π) of 16S/COI (0.00284/0.0013) of C. caretta was low compared to all other published sequences from population studies of barnacles attached to fixed substrate. However, the estimated levels of π from C. caretta were comparable to those reported from C. testudinaria, an epibiont barnacle on loggerhead turtles. Analysis of molecular variance and parsimony network analysis of the sampled turtle epibionts from Mona Island indicated that they are genetically homogeneous, irrespective of the host or its gender. Albeit that the sampling size is small, our results are consistent with the general prediction that higher rates of dispersal reduce population divergence and estimates of nucleotide diversity. Conservation concerns are raised about the status of Chelonibia caretta whose host (the hawksbill sea turtle) has been included in the Endangered Species List.

Hydrocoryne iemanja sp. nov. was found in an aquarium, growing on rhodoliths of coralline algae collected on the south-eastern coast of Brazil (20°40′S 40°2′W). The colonies were reared through maturity in the laboratory. Each colony had up to 7 sessile, long and thin monomorphic zooids, very extensible and flexible, arising from a chitinous, hard dark-brown plate with minute spines. Medusae budded from near the basal part of hydrocaulus, and were released in immature condition, acquiring fully developed interradial gonads 5–7 days after release. Asexual reproduction by longitudinal fission was observed on the hydrocaulus of the polyps, both for those in normal condition and those with injuries. Fission started at the oral region, extending aborally, with a new hard plate formed in the basal part of hydrocaulus. When fission reached the new hard plate, the new polyp detached, becoming free and sinking to the bottom, starting a new colony. Detached polyps were morphologically indistinguishable from other polyps, being able to produce medusae. Mother and daughter polyps undertook subsequent fissions. This mode of longitudinal fission is distinct from other modes of longitudinal fission, a process known for a few species of cnidarians. Further studies of this process may shed light on the understanding of the evolutionary pathways in Cnidaria and animals. Hydrocoryne iemanja sp. nov. is distinguishable from its two congeners by the distinct marginal tentacles of the medusae—short and with a median nematocyst knob—an unambiguous character useful even for the identification of newly liberated medusae.

The patterns of habitat use by the franciscana dolphins (Pontoporia blainvillei) along its distribution are poorly known. This study investigates the patterns of habitat use with respect to depth for 181 individuals of different age, size, gender and reproductive condition off Rio Grande do Sul, southern Brazil. The results reveal that franciscanas are very homogeneously distributed according to depth. Individuals from all lengths utilize nearly the entire range of depths of the surveyed area. Larger or older animals do not use deeper waters than younger animals, indicating that body size and age are not limiting factors for franciscanas that occupy deeper or offshore waters. Gestation seems to not cause a change in the distribution of females. Although the sex-ratio of the overall data did not vary from 1:1 in different depth intervals, a small-scale comparison between the northern and southern coast demonstrated the existence of some kind of sexual segregation. Franciscana by-catch in Rio Grande do Sul is not sustainable and it is agreed that management procedures are needed. Nevertheless, the available data on species distribution do not allow the designing of a protected area in order to minimize the by-catches of a particular sex/reproductive class.

The size–weight relationships, percentage water, ash-free dry weight and biochemical (protein, lipid and carbohydrate) contents of the coronate jellyfish species Periphylla periphylla have been analysed. A total of 48 medusae ranging in size from 13 to 80 mm bell diameter were collected from mesopelagic depths in the eastern Gulf of Mexico. The dry mass of whole medusae ranged from 1.12 to 10.53% of wet weight (mean 5.49%), while ash-free dry weight, a proxy for organic content, varied between 25.19 and 34.89% of dry weight (mean 30.14%). Preservation in 2% glutaraldehyde resulted in shrinkage in >75% of the medusae, with preserved bell diameters 2.9% to 28.6% smaller than the original fresh bell diameters. Preservation also produced a significant adjustment to the bell diameter to wet weight relationship. With regard to biochemical content, the typical gelatinous zooplankton trend of low carbohydrate (mean 8.99 mg gDW−1), intermediate lipid (mean 20.57 mg gDW−1) and high protein (mean 63.71 mg gDW−1) was observed. Although there was a high degree of variability in biochemistry, there was no apparent trend with size.

Novel predator–prey interactions are becoming increasingly relevant to investigate in the context of current geographical range expansions and biological invasions. This study describes a vigorous attack by a muricid whelk, Thais gradata on a mud-inhabiting mytilid mussel, Musculista senhousia, following new colonization of the mussel in the Brunei estuarine system (Borneo, South-East Asia). This represents only the second reported attack by a gastropod on this globally important invasive mussel species, and the first such attack in its native environment. Whelks migrated from their typical hard surface habitat and barnacle feeding to the sediment, where they aggregated and fed on the mussels. Field data suggest no selection by the whelks of the part of the mussel bed colonized or of the prey size attacked (median shell length = 21 mm). In addition to forming feeding aggregations, the whelks formed non-feeding resting aggregations off the mussel bed (sometimes of more than 80 individuals). These apparently facilitated synchronized mating and consequently the formation of large communal nests of egg capsules (involving approximately 3500 contributing females). During the investigation, the newly-formed mussel colony underwent mass mortality, and the whelks either redistributed on the sediment or returned to feeding on barnacles. The population-level response by the whelks described here maximizes energy transfer from prey resource to whelk propagation. In addition to the whelk's generality of habitat use and feeding behaviour, this is likely to contribute to sustaining populations in a system where prey abundance and distribution is limited by highly variable and extreme physicochemical conditions.

Population parameters and behaviour of the herbivorous fish Sarpa salpa, present differences between protected and non-protected seagrass meadows of the north-western Mediterranean Sea. Larger individuals are more abundant inside protected areas, where their grazing pressure on seagrass is disproportionately greater than that of smaller fish feeding on algae and seagrass in unprotected areas. The feeding rate (bites per minute per individual) of smaller fish in unprotected areas is relatively high; however, the denser populations of larger fish in protected areas consume more forage because individual mouth gape is greater and larger fish remove more forage per bite. All these differences suggest a higher impact on seagrass meadows inside protected areas.

Distribution of fur seals Arctocephalus australis has been studied in October 2007 on the western, southern and eastern Falkland shelves during the survey of spawning grounds of the red cod, Salilota australis. Fur seals presence/absence, numbers and sex were recorded at every oceanographic station. Animals were found foraging on the shelf edge south-west of the islands, in a productive zone with quasi-stationary eddies at a periphery of upwelling. It was also the zone of maximum abundance of lobster-krill, Munida spp.—an important food source of fur seals and aggregations of both red cod and blue whiting, Micromesistius australis. No fur seals were found in waters of the relative cold and saline Falkland Current as well as in the relatively warm, fresh and oxygen-rich waters of Argentine Drift. It allows supposing that position and extension of the foraging grounds are caused by oceanographic features determining distribution of prey species.

Most known algal toxins act on ion channels either directly or indirectly, resulting in a change in intracellular ion concentrations when administered to targeted cells. The present project developed the working conditions for the use of fluorescent dyes in monitoring changes in membrane potential, intracellular calcium, and intracellular sodium levels in mammalian cell lines. Using these conditions, we were able to demonstrate specific changes in fluorescent signals in response to several purified toxins. We were also able to generate algal extracts which, when administered to the developed fluorimetric assays, were able to elicit different pattern of changes in membrane potential, intracellular calcium, and intracellular sodium levels. The differential pattern of responses induced by the different algal toxins in the three fluorimetric assays serve as a proof of concept for the use of multiplex fluorimetric assays in the laboratory monitoring of algal toxins.

Seasonal growth pattern and reproductive biology of the Baltic prawn, Palaemon adspersus, were studied in the southern Black Sea between February 2002 and January 2004. The seasonal von Bertalanffy growth parameters, computed from monthly length–frequency distributions, were estimated as L∞ = 62.99 mm TL, K = 1.190 year−1, C = 0.815, and WP = 0.847 for females and as L∞ = 49.63 mm TL, K = 1.085 year−1, C = 0.011, and WP = 0.407 for males. Growth performance index of females (Φ′ = 3.67) was greater than it was for males (Φ′ = 3.43). Based on latitudinal gradients, water temperature negatively affected Φ′ of P. adspersus. Sexual dimorphism in size was evident, females being larger than males. This typically shallow water species was observed in water depths as deep as 30 m. Compared to shallower water depths, larger individuals were observed in deeper water depths. The size at sexual maturity for females (TL50) was estimated as 53.60 mm TL. Ovigerous females were recorded from March to August and juveniles appeared in the benthic population in August. Ovary development was related to photoperiod and occurrence of ovigerous females was linked to increased water temperature.

The hydrothermal-vent barnacle Vulcanolepas osheai of the subfamily Neolepadinae is one of the most conspicuous organisms at the Brothers Caldera, south Kermadec Arc, New Zealand. Like a neolepad species found in the Lau Basin, V. osheai harbours filamentous bacteria on its elongated cirral setae. To define the phylogenetic affiliation of the epibiotic bacteria and the nutrition of the barnacle host, we conducted molecular phylogenetic and isotopic analyses. Analysis of 16S rRNA gene sequences of microbial communities on the cirral setae showed that among 91 bacterial sequences investigated, 28 sequences were related to the ɛ-proteobacterial endosymbiont of Alviniconcha aff. hessleri; 11 sequences were related to the epibiont of the bresiliid shrimp Rimicaris exoculata. Fluorescence in situ hybridization showed that in contrary to results from the 16S rRNA gene-sequence library, approximately 80% of the filamentous bacteria hybridized with a probe targeting the sequences related to the epibiont of the bresiliid shrimp R. exoculata. The fatty-acid profiles of the filamentous bacteria and the host barnacle both contained high levels of monounsaturated C16 and C18 fatty acids, and the carbon isotopic compositions of the biomass and monounsaturated C16 and C18 fatty acids of both the bacteria and barnacle were nearly identical. This would suggest that the nutrition of the barnacle is highly dependent on bacteria thriving around the barnacle, including the epibiotic bacteria.

A decline in white-beaked dolphins Lagenorhynchus albirostris had been reported in the Minch (Scotland, UK) since the 1990s, coinciding with an increasing occurrence of short-beaked common dolphins Delphinus delphis. This has led to suggestions that rising seawater temperatures are causing D. delphis to out-compete and exclude L. albirostris in this region. A total of 793 km (66.3 hours) of survey data were collected in the Minch during August 2007, to examine fine-scale habitat selection by L. albirostris and D. delphis and investigate whether their ecological overlap is sufficient to result in interspecific competition and/or habitat partitioning. Ten sightings of L. albirostris (70 animals) were recorded in a relatively small spatial area in the northern Minch. In contrast, the eleven sightings of D. delphis (1486 animals) were more widely distributed. The relative abundance per 1/4 ICES rectangle ranged from 0.41 to 0.53 animals/km for L. albirostris and 0.13 to 6.68 animals/km for D. delphis. The mean group size and group body mass were higher for D. delphis than for L. albirostris indicating D. delphis as the dominant delphinid in the Minch during August. Lagenorhynchus albirostris occurred in waters significantly deeper and further from shore than D. delphis, suggesting interspecific differences in preferred habitat. Most dolphin schools were recorded as foraging/feeding. Behaviour and seabird associations indicated that the two species differed in diet and/or foraging strategy, with L. albirostris foraging sub-surface and D. delphis exhibiting surface-feeding with associated gannets Morus bassanus. This is consistent with published information on the stomach contents of Scottish animals. The results suggest that there are subtle differences in habitat selection and diet between these two species, which may enable L. albirostris and D. delphis to coexist in the Minch. Whether these differences result from niche partitioning arising from previous/ongoing interspecific competition or are the result of genuine differences in the habitat preferences of each species, remains unclear.

The aim of this study was to estimate growth parameters of two populations of Ligia exotica inhabiting discrete estuarine areas of Patos Lagoon, Rio Grande do Sul, Brazil. Sampling was performed fortnightly at two different estuarine zones, named Leonideo Island and West Breakwater, to detect different growth patterns for this species by using the von Bertalanffy growth model (VBGM). The VBGM estimated were as follows: TLmm = 34.57 (1−e−0.012(t−2.93)) (males in Leonideo Island), TLmm = 35.61(1−e−0.009(t−5.87)) (males in West Breakwater), TLmm = 30.11(1−e−0.009(t−5.84)) (females in Leonideo Island) and TLmm = 29.65(1−e−0.01(t−4.87)). Significant sexual dimorphism was observed, since males reach larger TL (mm) by higher k value (day) and consequently a faster growth pattern. Different growth patterns of males were also detected comparing both populations, in such a way that the West Breakwater individuals are larger than those from the Leonideo Island. One possible explanation is the higher food availability observed in the former site, as well as favourable environmental parameters, providing better conditions for individual growth. Briefly, two different populations of L. exotica were detected in the studied area, presenting discrete growth parameters highly influenced by environmental factors.

Respiration in marine bacteria (fraction <0.6 µm) was investigated in 5 distinct coastal ecosystems. Respiration rates were estimated from the decrease of dissolved oxygen (O2) concentrations measured with a fibre-optic oxygen sensor (optode) during short-term incubations (5 to 6 hours) in the dark. Sub-populations of heterotrophic bacteria were defined and enumerated by flow cytometric analysis. Respiration rates ranged from 0.04 to 0.14 µmol O2 l−1 h−1 and were not correlated to total bacteria abundances. In contrast, they significantly increased with the relative proportion of HDNA cells (i.e. high deoxyribonucleic acid content) within the bacterioplankton community. These results stress the need to relate bacterial respiration rates to the absolute and relative abundance of the different cytometrically defined sub-populations found in bacterial assemblages, rather than to total cell counts. This result indicates that only a fraction of bacterial cells may contribute to bacterial respiration, which indicates a reconsideration of the relevance of some previous estimates of bulk bacterial respiration and the related biogeochemical fluxes may be required.

Digenean trematodes are omnipresent in the cockle Cerastoderma edule, a common coastal bivalve of (semi-)sheltered north-eastern Atlantic coasts. They can use their host as a second intermediate host where they remain in a relatively latent stage as metacercariae. Cockle population dynamics and trematode parasite load were monitored for two years in two sites, Arcachon (France) and Merja Zerga (Morocco) for the cockle cohort of 2005. Individual growth was slightly higher at Arcachon than at Merja Zerga (Von Bertalanffy parameters: K = 1.5 yr−1 in both sites but L∞ = 31.2 mm at Merja Zerga against 38.3 mm at Arcachon). Production during cockle life was twice as high at Merja Zerga (48.5 compared to 22.2 gDW.m−2 at Arcachon). Elimination compensated production at Merja Zerga while elimination was low at Arcachon (8.1 gDW.m−2) due to sediment dynamics which concentrated cockles within the sampling area. P/B was similar in both sites (2.4–2.6 yr−1) while E/B was higher at Merja Zerga (2.2 yr−1 versus 1.0 yr−1). Trematode communities were similar in both sites in terms of species and abundance. During the cockle cohort lifespan, there were 3 to 5 events in the parasite abundance survey that suggested parasite-dependent mortality. At Merja Zerga, trematodes metacercariae did not affect P/B (2.4 yr−1) but increased E/B (+14%). At Arcachon, they also had no effect on P/B (2.6 yr−1) but on the contrary increased E/B (+20%). The threshold of metacercariae abundance beyond which cockles are affected was lower for Echinostomatid trematodes at Merja Zerga, suggesting an interaction with other factors such as temperature which is higher at the southern limit of cockle distribution.

Biometric relationships were recorded for 2431 male and female Panulirus echinatus sampled at Tamandaré coastal reefs, Pernambuco, Brazil. The following body measurements were taken: carapace length and width, abdomen length and width, total length, third and fifth pereiopod length, cephalothorax–abdomen and total weight. Twelve relationships were studied to compare the biometric characteristics of males and females. Eleven of them showed difference between the sexes. Comparing sexes with the same carapace length, males have a heavier cephalothorax and longer third and fifth pereiopods than females, whereas females are longer, wider, and have a heavier abdomen than males. For genders with the same total length, males are heavier and have a longer carapace than females, while females have a larger abdomen. For genders with the same abdomen length, males have a heavier abdomen than females. The relationships TWg/TL and AWg/AL showed positive allometric growth for the males. All other relationships involving weight, presented negative allometric growth for both sexes.

Recent studies of hydrozoans suggest that metabolic factors associated with the physiology of gastrovascular fluid transport play a role in regulating morphogenetic development of colonies. In that context, the objective of this study was to develop a system to experimentally control diets of hydrozoans in culture that could be used to test effects of specific compounds. This diet delivery system consisted of a known concentration of homogenate of brine shrimp nauplii that was solidified in a 1% agar block cut to the size of, and containing the equivalent of, a single, 2-day old brine shrimp nauplius larva. We tested the utility of this system by comparing the frequencies of ingestion, and rates of gastrovascular transport and growth following feeding, between polyps of Podocoryna carnea fed either a single brine shrimp nauplius (controls) or an agar cube including brine shrimp homogenate. Polyps fed experimental diets showed similar rates of gastrovascular transport (6 and 12 h after feeding) and growth (24 h after feeding) to those of polyps fed a brine shrimp nauplius suggesting that no significant artefacts existed associated with these response variables. However, the frequency of ingestion of experimental foods by polyps was much less than that by control polyps. These results imply that this system of delivery of experimental diets has potential as a means to manipulate physiological state and assay the effects on morphogenesis of hydrozoan colonies, but must first overcome limitations of low ingestion frequency.

A total of seven poorly known species of the genus Asterocheres, the largest genus of the family Asterocheridae, are redescribed based on material deposited in the Natural History Museum of London. Among the material available, there were specimens of both sexes of A. bulbosus, A. ellisi and A. rotundus; the dissected holotypes for A. hongkongensis, A. indicus and A. ovalis which have no other specimens; and only cotype of A. micheli, turned out to be lost. Some taxonomically important appendages of these species are described and illustrated for the first time. Furthermore, discrepancies have been observed in: (1) the general shape of the body; (2) the antennule segmentation; (3) the omission of some elements in various oral appendages; and (4) the segmentation of the mandibular palp. These redescribed species were then compared with their closest congeners.

The faunal composition within three mono-specific algal habitats was investigated at Likuri Island, southern Viti Levu, Fiji Islands. Gracilaria maramae was the dominant alga within algal drift mat, seagrass bed, and rocky substrate habitats at the study site. This algal species exhibits two distinctive morphologies depending on whether it is attached or loose-lying. When attached to seagrass blades or rocky substrates, this alga has long straight branches stemming from a single holdfast, while detached individuals develop curled tendrils that re-attach to adjacent substrates. Re-attachment behaviour and high growth rates result in a dense mat of drift algae, which provides a suitable micro-habitat for macro-invertebrates. The sources of algal fragments that contribute to the algal mat appear to be nearby seagrass beds and rocky substrates, where this species may settle directly from spores. Storm events may detach these algae, although pulling experiments showed that the attachment to rocky substrates is 5 times stronger than the attachment to seagrass blades. Results from the macro-faunal samples indicate that the loose-lying algal mat habitat had the highest abundance and biodiversity of organisms, followed by the seagrass bed, and then the rocky substrate habitat. The ability of loose G. maramae fragments to re-attach, along with their high growth rate, may provide a unique micro-habitat for highly abundant and diverse faunal assemblages, which in turn may sustain adjacent near-shore communities. This study highlights the ecological importance of floating algal mats to coastal ecosystems, which should be considered in future management strategies throughout the Fiji Islands.