The biology and ecology of the sea urchin Strongylocentrotus pallidus was studied using photographic transects and collected specimens from the Grand Bank of Newfoundland. Specimens measured from photographs along two transects showed...
moreThe biology and ecology of the sea urchin Strongylocentrotus pallidus was studied using photographic transects and collected specimens from the Grand Bank of Newfoundland. Specimens measured from photographs along two transects showed mean
diameters of 36.2 ± 7.2 rom and 31.9 ± 4.9 rom. Urchins greater than 50 rom were rare. Maximum density was 5 individuals per m2• Mean biomass estimates along transects ranged from 0.23 g/m2 to 9.92 g/m2. Overall mean gonad index was 4.9% for specimens collected in November below 70 m. There was no trend in G.I. with depth or station location. Gut analysis revealed an omnivorous diet with evidence of grazing on both sand and cobble substrates. Sea urchins occurred more frequently on mixed cobble-sand substrates than on sand or predominantly (>80%) cobble substrates. It is speculated that mixed cobble-sand substrates provide both mechanical stability for urchins as well as an optimum, varied
substrate for feeding.
