Comparative survival and growth of embryos, larvae, and juveniles of pejerrey Odontesthes bonariensis and O. hatcheri * at different salinities

Abstract

Summary The hatching of fertilized eggs and the survival and growth of larvae and juveniles of the inland‐water atherinids Odontesthes bonariensis (Valenciennes 1835) and O. hatcheri (Eigenmann 1909) were examined at salinities of 0, 5, 10, 20, and 30 ppt. In addition, a limited study compared the salinity responses of O. bonariensis eggs and larvae from different origins. Overall, embryos, larvae, and juveniles of both species were euryhaline, although best survival and growth rates were obtained at the intermediate salinities. Survival of O. bonariensis at 0 ppt varied from very good to very poor. Comparison of the salinity responses of eggs and larvae of O. bonariensis from the current Japanese strain with newly introduced strains from three locations in Argentina did not reveal a clearly superior strain for freshwater culture. In general, O. hatcheri showed higher survival and growth rates and better adaptability to fresh water compared with O. bonariensis. Although both species are commonly regarded as freshwater species, the results of this study emphasize the importance of millimolar quantities of salts in the rearing water for improved survival and growth.

The significance of cortisol on acclimation to salinity in pejerrey Odontesthes bonariensis

“…The lower cortisol levels at 5 and 20ppt after stress of transport or crowding of adult pejerrey as observed in previous studies (Tsuzuki et al, 2001) were possibly due to a natural preference for higher salinity levels, resulting in decreased cortisol secretion, or increased clearance rates, as pointed out by Goswami et al (1983), Redding et al (1984) and Nichols and Weisbart (1985). Data on the survival and growth of pejerrey larvae and adults at different salinities seemed to support the first hypothesis as both were shown to be euryhaline and to perform better at salinities close to 20ppt, especially compared to 0ppt (Tsuzuki et al, 2000a). This notion was reinforced by information on the natural distribution of this species, which, although continental, coincides with areas where surface and ground water have substantial salinity (Mc Donagh, 1934;Ringuelet et al, 1967;Saravia et al, 1987).…”

“…Pejerrey is considered as a freshwater species because of its natural occurrence in inland waters, and introductions domestically and to other countries have been made almost entirely in fresh water. However, recent studies revealed better performance, in particular higher survival and growth rates, at salinities of 5 to 20 parts per thousand (ppt) compared to 0ppt (Tsuzuki et al, 2000a;.…”

Survival and the growth of pintado (Pseudoplatystoma corruscans) post-larvae on different salinities

“…Low water salinity in post-larvae fish farming has less effect on the growth and survival than high salinities, as observed by Specker et al (1999) for Paralichthys dentatus. Several freshwater fish species show maximum growth and survival rates when reared in slightly salinized water, up to 5‰, such as Cyprinus carpio (Lam and Sharma, 1985), Odontethes hatcheri (Tsuzuki et al, 2000), Heterobranchus longifilis (Fashina-Bombata and Busari, 2003), whereas others like Ictalurus punctatus show reduced fingerling growth (Baldisserotto, 2002). In salinities above 1.7‰ reduced growth of pintado may have been caused by the high energy consumption to maintain inverse osmoregulation, i.e., eliminating salt and retaining water.…”

Fishes of southern South America: a story driven by temperature

“…Both species have a remarkable tolerance to high salinity but not to sea water (Tsuzuki et al 2000;Gómez and Ferriz 2001). Dyer (2000) and Menni (2004) agree in their view that both species were isolated by marine incursions several millions of years ago (Hubert and Renno 2006).…”