Macrobenthos of the San Diego Trough: photographic census and observations from bathyscaphe, Trieste

摘要: Abstract Deep-submersible vehicles provide a platform for acquiring quantitative and behavioral data on the larger, sparse, or more active deep-sea animals which are impossible to obtain by conventional sampling techniques. The distributions densities of such organisms were established from cine-camera films taken along 188-m transect at 1243-m depth. Densities in numbers organisms/m 2 following forms were: Ophiomusium lymani (a large ophiuroid) 8.7; Scotoplanes sp. (an elasipod holothurian) 0.01; Anoplopoma fimbria (sablefish) 0.005; Sebastolobus altivelis (crimson thornhead) 0.06. Still photographs, simultaneously also analyzed O. density. This method gives higher figure 15.1 specimens/m because small specimens can be distinguished Amphilepis other dimunitive ophiuroids. Their distribution is not homogenous. Areas high low density exist close proximity. Wet weight biomass this species ranges 22.6 39.3 g/m , contrast reported total fauna similar depths. Observations Trieste I dives show relative abundance lymani, sp., A. S. differs areas San Diego Trough. suggest that: may filter feed; could easily washed aside descending grab samplers; fishes relatively insensitive stimuli created deep-submersible vehicle.