BURROWING ACTIVITY OF NEOHELICE GRANULATA CRAB (BRACHYURA, VARUNIDAE) IN SOUTH WEST ATLANTIC INTERTIDAL AREAS

LETICIA LESCANO; CERVELLINI, PATRICIA M.; ANGELETTI SABRINA

CIENCIAS MARINAS

INST INVESTIGACIONES OCEANOLOGICAS, U A B C, APARTADO POSTAL 423

Lugar: Ciudad de México; Año: 2018 vol. 44 p. 155 - 167

0185-3880

The burrowing and semiterrestrial crab Neohelice granulata builds its burrows actively and constantly in the intertidal of the estuary of Bahia Blanca, during low tides. Differences in structural morphology of burrows and their burrowing activities in contrasting microhabitats (saltmarsh and mudflat) were analysed and related to several conditions, such as tide level, substrate type, sediments properties and population density. In mudflat a higher density of total burrows was found in autumn (172 burrows m-2), related to molt timing and a higher density of active burrows in summer (144 burrows m-2), was related to reproductive migration. Sediments collected from biogenic mounds (removed by crabs) had more water content and penetrability than sediment from surface (control), suggesting that bioturbation increases these values. Grain size distribution profiles and mineralogical composition didn?t vary between microhabitats neither between seasons. Burrows were all tunnel-shaped and only those from saltmarshes had chambers inside tunnels, possibly used for reproductive purposes. Burrows from saltmarsh had narrow entrances and deep tunnels and burrows from mudflats presented very narrow entrances and superficial tunnels. Differences in burrow features and burrow activity of Neohelice granulata between microhabitats are confirmed, related to biotic and abiotic factors, indicating that this species has an adaptive burrowing behaviour.