Can Pelagic Aggregations Cause Benthic Satiation? Feeding Biology of the Antarctic Brittle star Astrotoma Agassizii (Echinodermata: Ophiuroidea)
- Louis S. Kornicker
Published Online: 21 MAR 2013
Copyright 1986 by the American Geophysical Union.
Biology of the Antarctic Seas XVII
How to Cite
Dearborn, J. H., Ferrari, F. D. and Edwards, K. C. (1986) Can Pelagic Aggregations Cause Benthic Satiation? Feeding Biology of the Antarctic Brittle star Astrotoma Agassizii (Echinodermata: Ophiuroidea), in Biology of the Antarctic Seas XVII (ed L. S. Kornicker), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR044p0001
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1986
Print ISBN: 9780875901695
Online ISBN: 9781118666708
- Marine biology—Antarctic regions—Collected works
Information on the diet, feeding behavior, and surface morphology was obtained for Astrotoma agassizii, a large, simple-armed member of the suborder Euryalina found on the Antarctic shelf. Material was collected at South Georgia and along the Antarctic Peninsula between 1975 and 1983. Extremely long, flexible arms which can be produced into sinuous forms and tight coils, together with a combination of girdle hooklets, hooked and paddle-shaped arm spines, and long podia are employed to capture prey from the water column. Frequency-of-occurrence and points methods were used to examine the stomach contents of 115 specimens of Astrotoma agassizii, of which 78 (67.8%) contained food. Mean number of food types per feeding animal was 1.7, and mean fullness value was 1.8, on a scale of 16. The diet consisted of members of only two major taxa, Crustacea and Chaetognatha. Copepods occurred in 75.6% of brittle stars containing food and were the dominant prey group, followed by mysids (34.6%), chaetognaths (10.2%), and euphausiids (8.9%). Other prey included unidentified crustacean and organic remains, ostracodes, and amphipods. All copepods in the stomachs of Astrotoma were calanolds belonging to 12 species generally considered pelagic animals. Euchaeta antarctica and Calanoides acutus constituted about 80% of the stomach content copepods. This association of an herbivorous calanid and predatory euchaetid may result from the well-known seasonal migrations of Calanoides. Upon completing their epipelagic season, aggregations of lipid-rich, late-stage copepodids of C. acutus might be expected to attract larger pelagic predators, including the euchaetid. In shoal waters this association of downward migrating herbivores and their predators may bring these calanoids in close proximity to the substrate, thereby providing a rich, seasonally predictable food source to the brittle stars. These interactions suggest that carbon fixed in surface waters may be transferred to the benthos within a year. In addition, frequent reports of E. antarctica to 1000 m suggest similar carbon transfer to mesopelagic depths. The extent to which this influx of epipelagic carbon affects the predatory brittle star and euchaetid and influences benthic and mesopelagic biology remains to be determined.