Southernmost occurrence of Gobiosoma hemigymnum (Eigenmann & Eigenmann, 1888) on salt marshes of the Bahia Blanca estuary, Argentina: an unusual finding

Abstract

Salt marshes do not present favourable conditions for cryptic fish species to inhabit these areas, mainly due to dryness and high temperatures at low tides, and scarce places to hide. Despite the harsh environmental conditions, we report, for the first time, the occurrence of two specimens of the half-naked goby Gobiosoma hemigymnum at high marsh, between oysters and Spartina alteniflora stems. In this paper we report evidence of a possible positive effect of autogenic ecosystem engineer and invasive species, the Pacific oyster (Magallana gigas), over the gobid, Gobiosoma hemigymnum, found 600 km away from its southernmost normal range.