Efecto de los cangrejales de Chasmagnathus granulata en el uso de hábitat de cangrejos, peces y zooplancton.

PAULINA MARTINETTO

Reserva de Biosfera Mar Chiquita: Características físicas, biológicas y ecológicas.

Martin

Lugar: Mar del Plata; Año: 2001; p. 165 - 170

The purpose of this chapter is evaluated the effect of the burrowing crab Chasmagnathus granulta on the habitat use by other crabs (i. e. Cyrtograpsus angulatus), fishes and zooplankton. A significantly higher abundance of C. angulatus was found outside C. granulata crab bed than inside. Larger C. angulatus sizes were found inside crab bed than outside, meanwhile larger C. granulata sizes were found outside. Soft molting and mating pairs of C. angulatus were never found in crab beds. There are strong evidences that C. granulata displaces C. angulatus from soft bottom habitats, and these results showed that the habitat use of C. angulatus is affected by C. granulata. Fishes density did not differ significantly between habitats. Size frequency distribution, however, differed among the numerically dominant species. These differences likely reflect species-specific responses to variation in factors as availability of food inside and outside crab bed. The zooplankton showed higher diversity inside crab bed than outside. The burrows work as passive traps for organic matter, and probably for the suspended organisms in the water column. These results showed that crab beds directly or indirectly affect the habitat use by nekton.