An unusual record of the prawnFunchalia woodwardiJohnson (Crustacea: Decapoda)

Abstract

A large swarm of the seldom recorded prawn Funchalia woodwardi Johnson was detected acoustically off the South African west coast and sampled with an 8-m2 rectangular mid water trawl. The biomass was estimated from the volume of water filtered and from acoustic measurements of swarm dimensions to be about 1 460 tons. An alternative method, in which the strength of the returned echo from the swarm was estimated, indicated that the swarm density, and therefore the biomass, may have been very much greater. The difference between the two estimates was probably because of inadequate sampling owing to net avoidance.