Three New distributional records of Pen Shells (Bivalvia: Pinnidae) from Seagrass beds of Palk Bay Area in Tamil Nadu

The new occurrence of Three species of bivalves from Pinnidae family is recorded for the first time from Palk Bay area based on a live and dead shells collected from the Intertidal area . All the three species are under the family of Pinnidae, Pinna bicolor, Pinna deltodes and Pinna incurva . In seagrass bed of Thondi Coast, all the species of Pen shells Pinna bicolor, Pinna deltodes and Pinna incurva were embedded in muddy sand and found associated with seagrasses at inter-tidal area. It was also found buried in hard substratum associated with living zoanthids and soft coral. The collected specimens were identified as, (1) Pinna bicolor, (2) Pinna deltodes and (3) Pinna Incurva by using both morphometric and meristic characters. The paper described the taxonomic status and the description of the three species of bivalves collected from Palk Bay areas.

Development of low-cost image mosaics of hard-bottom sessile communities using SCUBA: comparisons of optical media and of proxy measures of community structure

Underwater image-based sampling procedures, using SCUBA, are compared using imagery collected from a temperate hard-substratum community. The effectiveness of a low-budget, high-resolution image mosaicing technique is assessed by comparing the relative efficiency of data collection, extraction and analysis among sampling procedures. In addition, a manipulative experiment tested whether the sampling procedures could detect the physical removal of 10% of the reef community. Overall, four factors were explored within the data: data collection media (stills and video), cover and community composition estimation techniques (visual cover estimation, frequency of occurrence and point extraction), change detection (pre- and post-impact) and depth (8, 14, 18 and 22 m). Stills imagery sampled the reef community at a higher image resolution than the video imagery, which enabled identification of more species and less-conspicuous benthic categories. Using the visual cover estimation technique, the stills imagery also had the greatest benefit in terms of efficiency and species identification. However, the experimental impact was detected using only the point extraction technique. The recommendations are that: (1) the image mosaicing technique is applied to fixed-station monitoring; (2) the point extraction technique be used for efficient and cost-effective monitoring at coarse taxonomic resolutions; and (3) survey depths remain constant over the duration of hard-substratum community monitoring.

Megafauna community structure and trophic relationships at the recently discovered Concepción Methane Seep Area, Chile, ∼36°S

Sellanes, J., Quiroga, E., and Neira, C. 2008. Megafauna community structure and trophic relationships at the recently discovered Concepción Methane Seep Area, Chile, ∼36°S. – ICES Journal of Marine Science, 65: 1102–1111. The fauna, community composition, and trophic support of the newly discovered Concepción Methane Seep Area (CMSA) are compared with those at a nearby non-seep control. The assemblage of chemosymbiotic bivalves is defined by eight species, including the families Lucinidae, Thyasiridae, Solemyidae, and Vesicomyidae. Seep polychaetes are represented by Lamellibrachia sp. and two commensal species of the vesicomyid Calyptogena gallardoi. Although taxonomic analysis is still under way, most of the chemosymbiotic species seem to be endemics. The CMSA is a hotspot for non-seep benthic megafauna too; 101 taxa were present, but most of them are colonists or vagrants (i.e. not endemics of methane seeps). Isotope analysis supported the belief that non-symbiont-bearing species utilize photosynthetically fixed carbon, because they were isotopically distinct from the chemosymbiotic bivalve species present. It is our opinion that, at this site, which underlies one of the most productive coastal upwelling regions of the world, spatial heterogeneity and the availability of hard substratum, generated by the presence of authigenic carbonate crusts, are more important factors in attracting non-seep fauna than the availability of locally produced chemosynthetic food.

Contribution of artificial reefs to the diet of the white sea bream (Diplodus sargus)

Leitão, F., Santos, M. N., and Monteiro, C. C. 2007. Contribution of artificial reefs to the diet of the white sea bream (Diplodus sargus). – ICES Journal of Marine Science, 64: 473–478. An evaluation of the trophic relationship between Diplodus sargus and artificial reefs (ARs) in the Algarve (southern Portugal) is based on a comparison of stomach contents and the macrobenthic communities present at the AR and in surrounding sandy bottom areas. Only adult white sea bream were observed in the vicinity of the ARs. The percentage of items found in the stomach that were characteristic of AR hard substratum was high (67%). Although the diet contained a wide variety of items, namely reef algae, invertebrates (crustaceans, gastropods, and bivalves), and fish, Balanus amphitrite and Gibbula spp. contributed most to the diet. The diet of D. sargus was strongly associated with prey availability on the AR, so highlighting the importance of these artificial habitats to the species. It seems that these artificial feeding areas, owing to their extent and benthic production, are enhancing the local D. sargus stock and hence the fishery.

Locating the barnacle settlement pheromone: spatial and ontogenetic expression of the settlement-inducing protein complex of Balanus amphitrite

Barnacles are prominent members of hard substratum benthic communities and their study has been important to advances in experimental ecology and contemporary ecological theory. Having recently characterized the cue to gregarious settlement of Balanus amphitrite , the settlement-inducing protein complex (SIPC), we use two polyclonal antibodies to examine the tissue distribution and ontogenetic expression of this glycoprotein. These antibodies were raised against two separate peptides located near the N- and C-termini of the SIPC and were used to detect the glycoprotein by western blotting and immunohistochemistry. By in situ hybridization we also show that the SIPC mRNA co-occurs with the expressed glycoprotein in the cuticles of both nauplius and cypris larval stages and the adult. In the larvae, the SIPC is expressed most strongly in the mouthparts and the hindgut of the stage 2 nauplius and in the thoracopods, antennules and bivalved carapace of the cyprid. In adult B. amphitrite , the expressed SIPC is present in protein extracts of the shell and in all organs that are lined by cuticular tissues. We suggest that the SIPC is produced by the epidermal cells that secrete the cuticle and discuss these observations with regard to earlier studies and the role of the SIPC as a contact pheromone.