Preprint volume - SIBM

More documents

Recommendations

Info

Pre-print Volume –Oral presentations Topic 4: THE ELASMOBRANCHS Fig. 3 – Porto S. Stefano: trend estimated with MAFA and correlations between variables and trend (significant correlations are in bold, p
Pre-print Volume –Oral presentations Topic 4: THE ELASMOBRANCHS C. PINTO, A. MANNINI, G. RELINI Centro Biolmar DIP.TE.RIS., Università degli Studi di Genova, V.le Benedetto XV, 3 – 16132 Genova, Italia. pinto.cecilia85@gmail.com REMARKS ON GALEUS MELASTOMUS IN THE NORTHERN LIGURIAN SEA OSSERVAZIONI SU GALEUS MELASTOMUS NEL NORD DEL MAR LIGURE Abstract – Galeus melastomus (Chondrichthyes, Scyliorhinidae) is a deep sea elasmobranch that is fished as a by-catch species of the bottom trawl fishery targeted to norway lobster and red shrimps. The mapping of its distribution shows that adults and juveniles occupy bottoms at different depths. Analyses of abundance doesn’t show significant trends in MEDITS while a decrease is detected in GRUND surveys. Key-words: Galeus melastomus, Selachians, trawl surveys, GIS, Ligurian Sea. Introduction – The study of by-catch species is considered significant in those kinds of fisheries that capture a wide range of species, as bottom trawling fishery does. Elasmobranchs are often part of by catch species and are reckoned as more vulnerable than other species, due to their biological and reproductive characteristics (Walker, 1998). This group is characterised by a slow growth, late attainment of sexual maturity and long life spans (Stevens et al., 2000), moreover they are often top predators in the trophic web, that is why they are taken in account as good indicator, both, of the “topdown” effect of the trophic chain, and of populations variations due to overfishing (Carbonell et al., 2003; Serena et al., 2002; Baum et al., 2003). The main objective of this work is the identification of areas of distribution of a deep sea elasmobranch, Galeus melastomus, in the northern Ligurian Sea, dividing the population into adults and juveniles to verify if the last ones have preferential habitats. Having a 15 years time series of data derived from seasonal bottom trawl surveys, we got the chance to observe the trend of abundance, biomass, mean weight and lengths distribution, to determine the population status of adults and juveniles. This species has been studied in the past, in the same area, concerning reproduction and feeding patterns (Orsi Relini and Wurtz, 1975). Materials and methods - The study area is the Northern Ligurian Sea, from the French borderline to the North Gorgona Isle (belonging to Tuscany Archipelago). The dataset used was made taking data from GRUND (autumn season) and MEDITS (spring season) scientific trawling campaigns based on a random stratified sampling scheme, using a dataset of 15 years, from 1994 to 2008. A total number of 248 and 213 hauls were carried out on bathyal grounds respectively in GRUND and MEDITS surveys. To realize the cartography representing the species distribution, we used mean points of trawling transects, representing them through ArcGIS 9.2. To have a more robust representation of the distributions using abundances of species, we put together abundances of all the 15 years for each fishing point and then realized an interpolation through the IDW technique building different maps for adults and juveniles (when data were available). Our interpolation has been limited to fishing points comprised between 200 m and 80 0m, since this species has never been found in shallower waters. We built trends to observe fluctuations of the population trying to assess the population 41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010 206
Page 2 and 3:
41 st Congress of the Società Ital
Page 4 and 5:
Pre-print Volume ROGHI F., PARRAVIC
Page 6 and 7:
Pre-print Volume Topic 3 / Tema 3 I
Page 8 and 9:
Pre-print Volume CARLUCCI R., CAPEZ
Page 10 and 11:
Pre-print Volume PORPORATO E., MANG
Page 12 and 13:
Pre-print Volume SOCAL G., BERNARDI
Page 14 and 15:
Pre-print Volume - Opening keynote
Page 16 and 17:
Pre-print Volume - Opening keynote
Page 18 and 19:
Pre-print Volume - Introductory lec
Page 20 and 21:
Page 22 and 23:
Pre-print Volume -Lecture Topic 1:
Page 24 and 25:
Pre-print Volume -Lecture Topic 1:
Page 26 and 27:
Pre-print Volume - Invited presenta
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Pre-print Volume - Oral presentatio
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Pre-print Volume - Posters Topic 1:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Phytoplankton Groups kg C m -3 3.00
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157: Pre-print Volume - Oral presentatio
Page 160 and 161: Genoa Sestri Levante Pre-print Volu
Page 172 and 173: Pre-print Volume - Posters Topic 3:
Page 194 and 195: Pre-print Volume -Invited presentat
Page 200 and 201: Pre-print Volume -Oral presentation
Page 220 and 221: Pre-print Volume -Posters Topic 4:
Page 222 and 223: 15 % Scyliorhinus canicula 12 GRUND
Page 240 and 241: Pre-print Volume - Posters AQUACULT
Page 256 and 257:
Pre-print Volume - Posters AQUACULT
Page 258 and 259:
Pre-print Volume BENTHOS COMMITEE B
Page 260 and 261:
Pre-print Volume - Posters BENTHOS
Page 262 and 263:
Page 264 and 265:
Page 266 and 267:
Page 268 and 269:
Page 270 and 271:
Page 272 and 273:
Page 274 and 275:
Page 276 and 277:
Page 278 and 279:
Page 280 and 281:
Page 282 and 283:
Page 284 and 285:
Page 286 and 287:
Page 288 and 289:
Page 290 and 291:
Pre-print Volume - Posters MANAGEME
Page 292 and 293:
Page 294 and 295:
Page 296 and 297:
Page 298 and 299:
Page 300 and 301:
Page 302 and 303:
Page 304 and 305:
Page 306 and 307:
Pre-print Volume NECTON AND FISHERY
Page 308 and 309:
Pre-print Volume -Posters NECTON AN
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Page 316 and 317:
Page 318 and 319:
Page 320 and 321:
Page 322 and 323:
Page 324 and 325:
Page 326 and 327:
Page 328 and 329:
Page 330 and 331:
Page 332 and 333:
Page 334 and 335:
Pre-print Volume - Posters PLANKTON
Page 336 and 337:
Page 338 and 339:
Page 340 and 341:
Page 342 and 343:
Page 344 and 345:
Page 346 and 347:
Pre-print Volume VARIOUS TOPICS VAR
Page 348 and 349:
Pre-print Volume - Posters VARIOUS
Page 350 and 351:
Page 352 and 353:
Page 354 and 355:
Page 356 and 357:
Page 358 and 359:
Page 360 and 361:
Page 362 and 363:
Page 364 and 365:
Page 366 and 367:
Page 368 and 369:
Page 370 and 371:
Castellano M.......................
Page 372 and 373:
Maravelias C.......................
Page 374:
Traversi I. .......................
show all

Preprint volume - SIBM

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?