Soft-bottom zoobenthic communities at Terra Nova Bay down to 100 m depth are mainly characterised by the presence of three species, generally occurring together and reaching high values of density: the scallop Adamussium colbecki (Smith 1902), the echinoid Sterechinus neumayeri (Meissner 1900) and the asteroid Odontaster validus Koehler 1911. These three species have a planktotrophic larval behaviour, but differ in terms of extent of gametogenic cycle and in feeding behaviour. The aim of this work is to give a first account of their reproductive conditions at Terra Nova Bay, comparing two following summer seasons, characterised by quite different ice-coverage and, consequently, food availability in the water column. The comparative analysis of the data evidences strong inter-annual differences in the scallop, a suspension-feeding species. In contrast, no significant changes were found in the two echinoderms, suggesting that a 2-year oogenic cycle, coupled with the opportunistic feeding behaviour, allow successful management of inter-annual shortcomings in food supply. On a latitudinal perspective, the comparison between data from McMurdo Sound and Terra Nova Bay shows small (for the echinoderms) or greater (for the scallop) geographical shifts in spawning occurrence.
Reproduction and condition of the scallop Adamussium colbecki (Smith 1902), the sea-urchin Sterechinus neumayeri (Meissner, 1900) and the sea-star Odontaster validus Koehler, 1911 at Terra Nova Bay (Ross Sea): different strategies related to inter-annual variations in food availability
CHIANTORE, MARIACHIARA;CATTANEO VIETTI, RICCARDO;
2002-01-01
Abstract
Soft-bottom zoobenthic communities at Terra Nova Bay down to 100 m depth are mainly characterised by the presence of three species, generally occurring together and reaching high values of density: the scallop Adamussium colbecki (Smith 1902), the echinoid Sterechinus neumayeri (Meissner 1900) and the asteroid Odontaster validus Koehler 1911. These three species have a planktotrophic larval behaviour, but differ in terms of extent of gametogenic cycle and in feeding behaviour. The aim of this work is to give a first account of their reproductive conditions at Terra Nova Bay, comparing two following summer seasons, characterised by quite different ice-coverage and, consequently, food availability in the water column. The comparative analysis of the data evidences strong inter-annual differences in the scallop, a suspension-feeding species. In contrast, no significant changes were found in the two echinoderms, suggesting that a 2-year oogenic cycle, coupled with the opportunistic feeding behaviour, allow successful management of inter-annual shortcomings in food supply. On a latitudinal perspective, the comparison between data from McMurdo Sound and Terra Nova Bay shows small (for the echinoderms) or greater (for the scallop) geographical shifts in spawning occurrence.
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