ABSTRACT In this work we studied the actual coverage, distribution patterns and ecologic effects of the introduced oyster Crassostrea gigas 20 y after their introduction to the Northern Argentinean Patagonia (Bahia Anegada; 39[degrees]50'S to 40[degrees]40'S and 61[degrees]59 to 62[degrees]28 W). Using satellite imagery and field and aerial inspections we found 10 oyster beds that cover less than 0.05% of the bay intertidal (area covered: 36.45 ha). These beds are restricted to ...
<0.005). In the low marsh, there were no differences in the number of mussels between treatments (t = 0.45, df = 18, P><0.05) but there were no differences in the number of mussels between plots ([X.sub.1] = 22.8, SD = 8.13, [X.sub.2] = 22.4, SD = 11.8; t = 0.09, df = 18, P><0.05) but there was no difference for the Oystercatcher (Mann-Whitney U-test, [Z.sub.adj] = 0.759, [N.sub.1] = 10, [N.sub.2] = 6, P>
<0.001 t-test, log
Brachidontes rodriguezi 1.44><0.05 M-W
Melita palmata 0.79>