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- Abundance and population structure of Plesionika narval (Fabricius, 1787) in the Northeastern AtlanticPublication . Sousa, R.; Pinho, M. R.; Delgado, J.; Pinto, A. R.; Biscoito, M.; Dellinger, T.; Henriques, P.Analysis of abundance and population structure of Plesionika narval was performed on data concerning 5,255 specimens obtained from 62 fishing sets carried out off the Madeira archipelago (Northeastern Atlantic) between 2004 and 2008 in a depth range from 101 to 350 m. Abundance ranged from 0.01 to 19.74 specimens-per-trap and significant differences were found between seasons, probably as a result of an increment of population in the spring during the recruitment season. The analysis of size distribution revealed that the carapace length (CL) ranged from 2.45 to 28.61 mm and that mean female size consistently exceeded that of males. Differences in mean CL were statistically significant between depth strata and seasons. Of the specimens sampled, 57.00% were males, 41.88% females and 1.42% undetermined. Sex ratio also differed significantly between seasons according to depth strata, consolidating the hypothesis of the existence of seasonal migrations related with the reproductive cycle of this species. Ovigerous females showed larger sizes and occurred all year around and remain in shallow waters in winter, summer and autumn and move to deeper waters in spring. The highest frequency of ovigerous females was recorded in summer, between 151 and 200 m deep supporting the hypothesis that spawning of this species occurs in shallow waters, especially in late summer.
- Transatlantic developmental migrations of loggerhead sea turtles demonstrated by mtDNA sequence analysisPublication . Bolten, Alan B.; Bjorndal, Karen A.; Martins, Helen R.; Dellinger, Thomas; Biscoito, Manuel J.; Encalada, Sandra E.; Bowen, Brian W.Molecular markers based on mitochondrial (mt) DNA control region se quences were used to test the hypothesis that juvenile loggerhead sea turtles (Caretta caretta) in pelagic habitats of the eastern Atlantic are derived from nesting populations in the western Atlantic. We compared mtDNA haplotypes from 131 pelagic juvenile turtles (79 from the Azores and 52 from Madeira) to mtDNA haplotypes observed in major nesting colonies of the Atlantic Ocean and Mediterranean Sea. A subset of 121 pelagic samples (92%) contained haplotypes that match mtDNA sequences observed in nesting colonies. Maximum likelihood analyses (UCON, SHADRACQ) estimate that 100% of these pelagic juveniles are from the nesting populations in the southeastern United States and adjacent Yucatan Peninsula, Mexico. Estimated contributions from nesting populations in south Florida (0.71, 0.72), northern Florida to North Carolina (0.19, 0.17), and Quintana Roo, Mexico (0.11, 0.10) are consistent with the relative size of these nesting aggregates. No contribution was detected from nesting colonies in the Mediterranean (Greece) or South Atlantic (Brazil), although samples sizes are insufficient to exclude these locations with finality. The link between west Atlantic nesting colonies and east Atlantic feeding grounds provides a more complete scientific basis for assessing the impact of subadult mortality in oceanic fisheries. Demographic models for loggerhead turtles in the western Atlantic can now be improved by incorporating growth and mortality data from juvenile turtles in pelagic habitats. These data demonstrate that the appropriate scale for loggerhead turtle conservation efforts is vastly larger than the current scale of management plans based on political boundaries.
- Larval cestodes infecting the deep-water fish, Cataetyx laticeps (Pisces: Bythitidae) from Madeira Archipelago, Atlantic OceanPublication . Costa, Graça; Khadem, Mahnaz; Dellinger, Thomas; Biscoito, Manuel; Moreira, Egberto MeloParasites of deep-water fishes are less known in comparison to the parasites of fishes living in the demersal and epipelagic ocean zones. In the present research note we report the occurrence of larval trypanorhynch cestodes in a rare deep-water fish, the deep-water brotula, Cataetyx laticeps. Based on the 28S rDNA (region D1-D3) sequence homology and the phylogenetic analysis, the larval cestodes are putatively assigned to the genus Grillotia. It is suggested that the definitive host of this trypanorhynch is a batoid.
- Gill monogeneans of the chub mackerel, Scomber japonicus from Madeiran waters of the Atlantic Ocean, PortugalPublication . Costa, G.; Freitas, N.; Dellinger, T. H.; MacKenzie, K.Five species of monogeneans were recovered from the gill filaments of 181 chub mackerel, Scomber japonicus, from the Madeiran waters of the Atlantic Ocean, Portugal, during 2004/2005. The monogenean Pseudokuhnia minor showed the highest prevalence (98.68%) and a mean intensity of 28.23, followed by Kuhnia scombri (prevalence of 43.71% and mean intensity of 2.69) and K. scombercolias (prevalence of 39.1% and a mean intensity of 1.81). Kuhnia sprostonae and Grubea cochlear were rare, occurring in only one and five fish hosts respectively. No correlation between fish host length and mean intensity of infection with the three most abundant monogeneans was found. However, significant differences in prevalence and abundance were found in relation to date of sampling for P. minor, and all parasites were aggregated in their distribution.
- Mar e recursos marinhos no arquipélago da MadeiraPublication . Dellinger, Thomas