Diet and Reproduction of Largemouth Bass in a Recently Introduced Population, Lake Bracciano (Central Italy)

Abstract

This paper concerns a study of some aspects of largemouth bass ecology in an Italian lake (Lake Bracciano). We assessed the success and possible impact of its recent introduction (1998) upon the fish community. From October 2001 to September 2002, 162 individuals were caught, measured, aged and submitted to biopsy (stomach and gonads were removed). Four age classes, from 0 + to 3 +, were observed in the population. Largemouth bass feeding activity was high in June, mostly eating fish (55.7%), crustaceans (in particular Palaemonetes antennarius, 37.5%), insects (4.5%) and molluscs (2.3%). The G.S.I. values showed an autumnal breeding period (from December to February) rather than the spring-summer one frequently described in North America. Moreover, bass attained sexual maturity during the second year of life (1 +). These differences could be related to its recent introduction and the apparent success could represent a problem for other species in the Lake.

Reproducción de <i>Micropterus salmoides</i> (Pisces: Centrarchidae), en el embalse Gustavo Díaz Ordaz, Sinaloa, México

“…Olague (2007) encontró que la proporción sexual de la lobina en la presa José López Portillo, Sinaloa, México fue a favor de las hembras en una relación 1.26H:1M. Un estudio sobre lobina realizado en el lago Bracciano, Italia se reporta una relación entre sexos de 0.8:1 a favor de las machos (Marinelli et al 2007). Quizás la diferencia en la proporción de sexos en las poblaciones muestreadas de M. salmoides en los diferentes embalses tenga que ver con su comportamiento reproductivo; es decir, que el macho se encarga de construir el nido y cuida los huevecillos hasta su eclosión por lo que su movimiento se restringe alrededor del nido.…”

“…Torres (1988) encontró que en la presa Rodrigo Gómez, Nuevo León, México el periodo reproductivo de M. salmoides abarca de febrero a mayo. En cuerpos de agua de otras regiones del mundo tal como el lago Trasimeno (Umbria, Italia) M. salmoides se reproduce principalmente en mayo (Lorenzoni et al 2002), en tanto que en el lago Bracciano (Centro de Italia), establecen la época de reproducción entre diciembre y febrero (Marinelli et al 2007). En el lago Chicalma (Mozambique) la reproducción ocurre en agosto y septiembre (Weyl & Hecht 1998).…”

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

“…In the remaining 8 fish species, sub-adult and/or adult of shrimps were the most preyed life stage and occurred in stomachs of all size classes with the only exception of the Esox lucius 40-45 cm class . Additionally P. antennarius was easily recorded in predators (mainly in small sized specimens) such as E. lucius Linnaeus, 1758, Micropterus salmoides (Lacépède, 1802), and Perca fluviatilis Linnaeus, 1758 (see also Marinelli et al, 2007;Scalici et al, 2009a;Godinho and Ferreira, 2014). Generally, the occurrence frequency (Table 2) showed a wide value range for the entire sample having a minimum of 0.08 for the diverse species and a maximum of 0.67 Fig.…”

Italian aquaculture and the diffusion of alien species: costs and benefits

“…Few species of Asian alien cyprinids are occasionally farmed in Italy: grass carp ( Ctenopharyngodon idellus ), bighead carp ( Hypophthalmichthys nobilis ) and silver carp ( Hypophthalmichthys molitrix ). Largemouth bass ( Micropterus salmoides ) has been introduced in Italy at the beginning of 20th century, and it is an active predator that inhabits lentic waters (Marinelli, Scalici & Gibertini ; Zerunian et al . ).…”