ICZ2008 – Abstracts S20 Fat reserves and moisture content in relation to sexual cycle <strong>of</strong> sardine, Sardina pilchardus (Walbaum., 1792), in the eastern middle adriatic fishery grounds Gorenka Sinovčić and Bosiljka Mustać Institute <strong>of</strong> oceanography and Fisheries, Split, Croatia The fat reserves, moisture and sexual cycle <strong>of</strong> sardine, Sardina pilchardus (Walbaum, 1792), were studied from monthly random samples <strong>of</strong> purse seine catches from March 2004 to February 2005. Catches were realised in <strong>of</strong>fshore (Dugi Otok) and inshore waters (Virsko more) <strong>of</strong> the Mid Adriatic Sea. A total <strong>of</strong> 1,219 sardine specimens were collected, out <strong>of</strong> which 668 were males and 541 females. Fish were measured, weighed and sexed. The sexual cycle analysis was based on the temporal evolution <strong>of</strong> gonadosomatic index and gonad mass. Gonadosomatic index (GSI) was calculated by expressing the monthly gonad weight as a proportion <strong>of</strong> the total body weight. The fat content was examined on the basis <strong>of</strong> monthly analyses <strong>of</strong> mesenteric fat in the visceral cavity and by determining the amount <strong>of</strong> lipid content in sardine tissues using Soxhlet’s s method. The total length <strong>of</strong> sardine ranged from 13.0 to 19.0 cm and the mass ranged from 16.72 to 51.45 g. The reproductive period was from October to May, coinciding with the highest gonad weights and gonadosomatic indices. The mean percentage <strong>of</strong> mesenteric fat grades in visceral cavity points to the greatest fat quantities in August, when grade 4 (fattest fish) presence amounted to 72%. The value is the result <strong>of</strong> an increase <strong>of</strong> mesenteric fat started in June and proceeding in the successive months until October. During autumn, a decrease trend is evident and it becomes pronounced in winter and spring when the lowest mesenteric fat quantities are recorded. Thereafter an increase in mesenteric fat for sardine was recorded, indicated by the records <strong>of</strong> grades 3 and 4. Due to such variations in mesenteric fat and tissue lipid during year, i.e. its greatest levels in summer (out <strong>of</strong> spawning) and lowest levels in the colder part <strong>of</strong> the year (during sardine spawning), it was assumed that quantity <strong>of</strong> sardine fat was affected by its sexual cycle. Lipid content in terms <strong>of</strong> sardine tissue dry weight showed the same trends as mesenteric fat - highest amounts during resting phase <strong>of</strong> reproduction (41.1%) and lowest during the peak <strong>of</strong> spawning (1.0- 2.2%). Amounts <strong>of</strong> total lipids and moisture in sardine tissues showed that females had more fat content and less moisture than males. An inverse correlation between fat content and sexual cycle on one side and lipid content and moisture on the other has been noted. Nutritional strategies <strong>of</strong> Pectinodonta sp., a gastropod associated with sunken woods Magali Zbinden 1,2 , Marie Pailleret 1,2,3 , Juliette Ravaux 1,2 , Sébastien Halary 1,2 , Françoise Gaill 1,2 and Sébastien Duperron 1,2 1 UPMC, Laboratoire Systématique Adaptation et Evolution, 7 Quai St Bernard, 75252 Paris, France; 2 CNRS, UMR7138, Systématique, Adaptations, Evolution, AMEX, 7 Quai St Bernard, 75252 Paris, France; 3 CNRS UMR 5143 Paléodiversité et Paléoenvironnements, Laboratoire de Paléobotanique, UPMC, 12 rue Cuvier, 75005 Paris, France The occurrence <strong>of</strong> sunken wood and vegetal debris in deep oceanic environments has been known for a long time (Murray 1895; Wolff 1979). Sunken woods are abundant in the deep sea, at all depths, with higher densities near estuaries, and in sedimentary accumulation basins. Wood reaches abyssal depths in sufficient quantity to support locally the development <strong>of</strong> long-lasting ecosystems, playing a key role in the deep sea (Cayré & Richer de Forges 2002). The faunal diversity that colonize sunken woods is widespread, comprising gastropod, polyplacophoran and bivalve molluscs, decapod and peracarid crustaceans, polychaetes, and echinoderms (Turner 1973, 1977, Cayré & Richer de Forges 2002). Until now, the only well known organisms able to degrade wood (thanks to symbiotic association with cellulolytic bacteria) and to use it as a food source are wood boring mollusca (Teredinidae and Xylophagainae) and isopodes crustacea (Limnoridae) (Gareth Jones et al. 2001). - 85 - During several cruises dedicated to sample sunken woods around Vanuatu, some species were observed stuck in hollows that they seem to dig at the surface <strong>of</strong> dregded woods. The most numerous species observed is a true limpet (Patellogastropoda) <strong>of</strong> the genus Pectinodonta, the species being still undescribed. The present work combine various approaches (microscopic observations <strong>of</strong> the radula, gills, and gut content; molecular methods to determine occurrence, localisation and phylogenetic position <strong>of</strong> associated microorganisms, and enzymatic assays to look for cellulolytic activity) to determine wether wood is a food source for this species and what are the terms and conditions <strong>of</strong> its degradation. New insigths on the metabolic diversity among the epibiotic microbial communitiy <strong>of</strong> the hydrothermal shrimp Rimicaris exoculata Magali Zbinden 1 , Bruce Shillito 1 , Nadine Le Bris 2 , C. de Villardi de Montlaur 1 , E. Roussel 3 , F. Guyot 4 , Françoise Gaill 1 and Marie- Anne Cambon-Bonavita 3 1 UMR CNRS 7138, Systématique, Adaptations et Evolution, UPMC, 7 Quai Saint Bernard, 75252 Paris cedex 05, France: 2 Département Environnement Pr<strong>of</strong>ond, Ifremer DRO, BP 70, 29280 Plouzané, France; 3 Laboratory <strong>of</strong> Microbiology <strong>of</strong> Extreme Environments, Ifremer Brest, LM2E, UMR 6197, BP 70, 29280 Plouzané, France; 4 Institut de Physique du Globe de Paris, Laboratoire de Minéralogie-Cristallographie, Université Paris-Jussieu, Tour 16, Case 115, 4, place Jussieu, 75 252 Paris Cedex 05, France The shrimp Rimicaris exoculata (Williams and Rona, 1986) dominates the megafauna <strong>of</strong> some <strong>of</strong> the Mid Atlantic ridge hydrothermal vent sites. This species harbors a rich community <strong>of</strong> bacterial epibionts inside its gill chamber. Literature data indicate that a single 16S rRNA phylotype dominates this epibiotic community, and is assumed to be a sulfide-oxidizing bacteria. However attempts <strong>of</strong> cultivation were not successful and did not allow to confirm it. The aim <strong>of</strong> our study was to test the hypothesis <strong>of</strong> sulfide oxidation in the gill chamber, by a multidisciplinary approach, using in vivo experiments at in situ pressure in the presence <strong>of</strong> sulfide, microscopic observations and a molecular survey. Morphology <strong>of</strong> microorganisms, before and after treatment, was analyzed to test the effect <strong>of</strong> sulfide depletion and re-exposure. Our observations, as well as molecular data indicate a wider diversity than previously described for this shrimp’s epibiotic community. We observed occurrence <strong>of</strong> bacterial intracellular sulfur- and iron-enriched granules and some methanotrophic-like bacteria cells for the first time. Genes that are characteristic <strong>of</strong> methane-oxidizing (pmoA) and sulfide-oxidizing (APS) bacteria were identified. These results suggest that three metabolic types (iron, sulfide and methane oxidation) may co-occur within the epibiont community associated with Rimicaris exoculata. As this shrimp colonizes chemically contrasted environments, the relative abundance <strong>of</strong> each metabolic type could vary according to the local availability <strong>of</strong> reduced compounds.
S20 ICZ2008 - Abstracts New records <strong>of</strong> host-parasite interactions between garfish Belone belone (Linnaeus, 1761) and Copepod Peniculus fistula von Nordmann, 1832 (Siphonostomatoidea, Penelidae) in the Adriatic sea Barbara Zorica, Gorenka Sinovčić and Olja Vidjak Institute <strong>of</strong> Oceanography and Fisheries, Šetalište I. Meštrovića 63, P.O. Box. 500, 21000 Split, Croatia Garfish, Belone belone (L., 1761), is a migratory pelagic species that occurs in the north eastern Atlantic, Mediterranean and Black Sea. In the Adriatic Sea this species is widely distributed in costal and open sea waters. Four samples <strong>of</strong> garfish individuals were caught by purse seine and beach seine in the eastern mid-Adriatic Sea between February and March 2008. Out <strong>of</strong> 224 analysed specimens <strong>of</strong> garfish, 22.3% were infested by crustacean ectoparasite identified as Peniculus fistula von Nordmann, 1832. The ectoparasites ranged from 1 to 7 per host with a mean intensity <strong>of</strong> 1.64. The parasites were attached to the fins - 62.2% to the ventral fins, 20.7% to the pectoral fins, 11.0% to the anal fin, 4.9% to the dorsal fin and 1.2% to the caudal fin. There was no correlation between the total length <strong>of</strong> the host and the number <strong>of</strong> ectoparasites (R=0.0715, p=0.622). The present study has been undertaken not only to register parasitic copepod P. fistula as a parasite on B. belone (L., 1761) for the first time, but also to contribute to the knowledge <strong>of</strong> pennellid fauna in this region. Besides, this parasite species might potentially be used as one <strong>of</strong> the biological tags for garfish stock discrimination in the Mediterranean and Adriatic Sea, inclusively. - 86 -
Change language