Role of the clam Neilonella sulculata as substrate for the hydroid Bougainvillia macloviana on muddy bottoms of San Jorge Gulf (Argentina, Southwest Atlantic)

GABRIEL NESTOR GENZANO; GABRIEL NESTOR GENZANO; LOPEZ GAPPA; LOPEZ GAPPA; LUIZZI M.; LUIZZI M.

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: Londres; Año: 2016 vol. 12 p. 888 - 893

1745-1000

The clam Neilonella sulculata is the dominant bivalve on muddy bottoms along the Argentinecontinental shelf (Southwest Atlantic). The medusa stage of the hydroid Bougainvilliamacloviana is one of the most abundant species in the gelatinous zooplankton of theMagellan region. Two benthic surveys carried out in 2007 and 2009 in San Jorge Gulf gaveus the opportunity to analyse (1) the interaction between N. sulculata and its epibiont,B. macloviana, and (2) the role of the clam as hard substrate in a depositional areacharacterized by silt/clay sediments. Bougainvillia macloviana has a high prevalence on theposterior region of live clams. The presence of gonophores shows that these small coloniesare able to reproduce there. Hydroid colonies are very rare on dead valves of N. sulculataand also on almost all other live bivalve species in the study area. Specimens of N. sulculatawith hydroids were slightly but significantly larger than those without them, both in 2007and 2009. The high prevalence of B. macloviana on live individuals of N. sulculata and itsalmost total absence on other clam species suggest that this association may be critical atleast for the epibiont and not the result of chance alone.