DISTRIBUTIONAL PATTERNS AND DIETS OF 4 SPECIES OF SEA-URCHINS IN GIANT-KELP FOREST (MACROCYSTIS-PYRIFERA) OF PURETO-TORO, NAVARINO ISLAND, CHILE
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1984
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Abstract
The distribution pattern of microhabitat and diet was studied in 4 spp. of sea urchins (Loxechinus albus, Pseudechinus magellanicus, Arbacia dufresnei, Austrocidaris canaliculata) in a forest of M. pyrifera in southern Chile. There is no overlap in space utilization (microhabitat) except for the species pair P. magellanicus-A. canaliculata. All 4 spp. of sea urchins feed on M. pyrifera in different percentages; this results in a high diet overlap in at least 3 of them; this resource does not appear to be limiting. Neither competition among adults nor predation on adults appears to be a key factor in regulating the present population desenties of the 4 spp. of sea urchins in the habitat studied. Differences in intensity of water movement, correlated with bathymetric distribution, regulate population density, size of test and biomass in these 4 spp.