Early life history traits of the blackfin notothen, Trematomus scotti, were investigated through otolith microincrement pattern and stomach content analyses. Post-larval specimens of 12-20 mm standard length (SL) were collected in the Bransfield Strait and adjacent waters during the 2010-11 summer. Catches were unevenly distributed across the surveyed area, yielding a relative abundance of 0.3-3.6 specimens per 1000 m3 of filtered sea water. Age estimates ranged from 34 to 67 days, with good consistency and no apparent bias between readings. Based on an exponential model fitted to the age-length dataset, the growth rate was 0.17 mm day-1, corresponding to a daily percentage increment in size of 1.07% SL. In agreement with previous studies, larval hatching occurred at a mean size of 9.0 mm and was spread over a relatively short period, lasting from late December to late January. Prey composition consisted exclusively of copepods, mainly larval stages of copepodites. Feeding intensity ranged from 1-14 prey items per stomach, being positively correlated with larval fish size. In summary, T. scotti shares a common early life history strategy with several other notothenioids, consisting of small larvae hatching in summer and overwintering as pelagic early juveniles until the following summer season.
Early life history traits of the blackfin notothen, Trematomus scotti in the Bransfield Strait
M La Mesa;
2015
Abstract
Early life history traits of the blackfin notothen, Trematomus scotti, were investigated through otolith microincrement pattern and stomach content analyses. Post-larval specimens of 12-20 mm standard length (SL) were collected in the Bransfield Strait and adjacent waters during the 2010-11 summer. Catches were unevenly distributed across the surveyed area, yielding a relative abundance of 0.3-3.6 specimens per 1000 m3 of filtered sea water. Age estimates ranged from 34 to 67 days, with good consistency and no apparent bias between readings. Based on an exponential model fitted to the age-length dataset, the growth rate was 0.17 mm day-1, corresponding to a daily percentage increment in size of 1.07% SL. In agreement with previous studies, larval hatching occurred at a mean size of 9.0 mm and was spread over a relatively short period, lasting from late December to late January. Prey composition consisted exclusively of copepods, mainly larval stages of copepodites. Feeding intensity ranged from 1-14 prey items per stomach, being positively correlated with larval fish size. In summary, T. scotti shares a common early life history strategy with several other notothenioids, consisting of small larvae hatching in summer and overwintering as pelagic early juveniles until the following summer season.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
