A growth cline in encrusting benthos along a latitudinal gradient within Antarctic waters

Growth and mortality of 3 species (Inversiula nutrix, Celleporella bougainv illei, Fenestrulina rugula) of encrusting bryozoans were examined from 5 An tarctic localities, along a latitudinal gradient. Typically, growth in mari ne invertebrates is, for ecological equivalents, slower or much slower in c old seas than warm waters. Contrary to the general trend, growth rates of 3 bryozoans were found to accelerate with increasing latitude in Antarctic w aters. Population age structure also showed a dramatic change across the 5 study sites (from 54 to 68 degrees S) through hugely increased mortality wi th increasing latitude. Reduction in inter-specific competition is theorise d as explaining higher growth rates. Increased levels of ice scour are prob ably responsible for the differential mortality.