The biology of Roule's goby in the Kvarner area, northern Adriatic Sea

Abstract

Roule's goby Gobius roulei in the Kvarner area of the northern Adriatic Sea attained ≥ 87.5 mm LT and an age of 7 years. In both sexes gonad development began in their second year. All males were mature by 3 years, and females by 4 years. Fecundity was related to LT and varied between 1200 and 8000 eggs. The breeding season lasted from April to August. Nests were built under empty shells of Pitaria chione or stones. Roule's goby was a predator and picker, feeding mostly on mobile benthic fauna, including bivalves, gastropods, polychaets, pagurids, mysids, gammarids and fishes. Larger specimens ate mainly macrofauna, while smaller specimens ate both meiofauna and macrofauna.

Biological Characteristics of Rock Goby, <I>Gobius Paganellus</I> (Actinopterygii: Perciformes: Gobiidae), in the South-Eastern Black Sea

“…Ontogenetic diet shift of the rock goby was similar to that reported from northern Spain population, without seasonal differences (Maze 2004). It is generally found that in gobies the feeding intensity is strongly related to the sea water temperature (Collins 1981, Joyeux et al 1991, Kovačić 2001, 2007. A similar finding was also observed in the present study, as G. paganellus showed a low feeding intensity in winter and spring when the sea water temperature was at the lowest level of the year.…”

“…The maximum size of the specimens recorded in this study was similar to the Atlantic populations (Azevedo and Simas 2000), as well as the longevity estimated for both sexes (7-10 years) (Miller 1961, Dunne 1978). Other European Gobius species shown high longevity and variability (2-10 years) (Vaas et al 1975, Fabi and Giannetti 1985, Nash 1984, Vesey and Langford 1985, Joyeux et al 1991, Arruda et al 1993, Sasal et al 1996 Monthly fullness index (I F ) ( ) of Gobius paganellus from the south-eastern Black Sea, and monthly temperature of sea water Silva and Gordo 1997, Kovačić 2001, 2006. The von Bertalanffy growth parameter L ∞ of G. paganellus was similar to previous studies in north-east Atlantic and Mediterranean Sea.…”

“…Conversely, instantaneous growth rate (k) and growth performance (φ') of G. paganellus were smaller than populations of Azores (Azevedo and Simas, 2000) but similar to north-east Atlantic population (Miller 1961, Dunne 1978. The sex ratio was similar to other gobiids, such as G. niger (see : Nash 1984), G. roulei (see : Kovačić 2001), andG. vittatus (see: Kovačić 2007).…”

“…Instead, sexual maturity of G. paganellus in the north-east Atlantic was reached in the second year of age (Miller 1961) or in the third one (Dunne 1978). The spawning period was from March to June in the Black Sea, like all other Gobius species from the north-east Atlantic and Mediterranean Sea (Miller 1961, Gibson 1970, Vaas et al 1975, Dunne 1978, Nash 1984, Vesey and Langford 1985, Joyeux et al 1991, Arruda et al 1993, Silva and Gordo 1997, Azevedo and Simas 2000, Kovačić 2001, 2007. The annual variation of hepatosomatic index showed that the energy storage decreased during the spawning season and increased afterwards.…”

“…Sorted prey items were weighed wet to the nearest 10 µg after blotting dry on absorbent paper. The quantitative importance of different prey in the diet was analyzed as follows: percentage frequency of occurrence (%F, the percentage of stomachs in which a certain item occurs in relation to all stomachs containing food); percentage number (%N, each prey item as percentage of total number of food items in the sample); percentage (Zander 1982, Kovačić 2001, 2007. The ontogenetic shift in diet was examined comparing the main food index between fish size classes.…”