The freshwater grass shrimpPalaemonetes antennariusin the diet of fish in Lake Bracciano (Central Italy)

Abstract

-We evaluated the importance of the freshwater grass shrimp Palaemonetes antennarius as trophic source for the lacustrine fish of the Lake Bracciano (Central Italy) analyzing 6120 stomach contents of 10 species. Shrimp was recorded for all size classes of the investigated species with a variation in frequency and abundance depending on seasons. P. antennarius was occasionally preyed by cyprinids, and systematically by small individuals of carnivorous fish. Our findings acquire more importance if we take the shrimps ecological niche into account, as it is potentially acting as detritivorous/generalist and predator of benthic invertebrates as well. This feeding behavior makes P. antennarius an important network ring, being a taxon that ought to receive the same attention recommended for other freshwater decapods as proposed for Austropotamobius pallipes and Potamon fluviatile.

On the Status of Threespine Stickleback (Gasterosteus aculeatus Linnaeus 1758) in Lake Bracciano, Italy

“…Capturing these would require increased sampling efforts using gill nets [16]. Nevertheless, combining our observation with (i) the absence of stickleback in a recent biodiversity assessment of the Bracciano region [10], (ii) the accounts of professional fishermen suggesting that stickleback were abundant until the 1980s but are not caught nowadays, and (iii) a comprehensive investigation of stomach contents for piscivorous species in Lake Bracciano failing to retrieve stickleback [17], an extinction of stickleback in the Lake Bracciano region seems yet likely.…”