Benzocaine and clove oil as anesthetics for pejerrey (Odontesthes bonariensis) fingerlings

Abstract

Pejerrey (Odontesthes bonariensis) is a native species from Rio Grande do Sul, Uruguay and Argentina where it is of great economic importance for artisanal fishing. One difficulty in laboratory research with pejerrey is related to its sensitivity, as it presents higher basal cortisol levels than other freshwater species. For this reason, the aim of this work was to evaluate the efficiency of benzocaine and clove oil as anesthetics for pejerrey fingerlings. Two experiments were done where fingerlings (57±7.8mm and 1.1±0.44g) were exposed to benzocaine with concentrations between 40mgL -1 and 120mgL -1 and to clove oil with concentrations between 12mgL -1 and 75mgL -1 . Survival, anesthesia induction time and recovery time for each pharmaceutics were evaluated. Both benzocaine and clove oil pharmaceutics showed efficiency as anesthetics for pejerrey fingerlings, with negative correlation between the dose of anesthetics and the anesthesia induction time. For benzocaine, the concentrations between 80mgL -1 and 100mgL -1 showed better results, as for clove oil the optimal concentrations were between 25mgL -1 and 50mgL -1 . On the other hand, the anesthesia recovery time did not present significant variation on the different concentrations of the tested products. The tested products are highly metabolizable by pejerrey.

Mobilization of energetic substrates in the endangered catfish Steindachneridion parahybae (Siluriformes: Pimelodidae): changes in annual reproductive cycle in captivity

“…We chose not to handle the animals in the fish ponds during these months to avoid the stress and emergence of diseases, such as the one caused by the ciliate Ichthyophthirius multifiliis, avoiding the known risks of mortality during these months (Hurst, 2007). Fish were anesthetized with 0.1% benzocaine (ethyl-paminobenzoate) following the literature (Gilderhus, 1990;Morato-Fernandes et al, 2013); and each animal had the total length (cm) and total body weight (g) recorded. Then, fish were killed by decapitation at the level of the operculum and dissected.…”

The efficacy of clove oil for anaesthesia of eight species of Australian tropical freshwater teleosts

“…Clove oil is derived from the flower buds, i.e., cloves, of the clove tree Syzygium aromaticum (L.) Merrill and Perry (Myrtaceae) (Chaieb et al 2007). Effective concentrations of clove oil for anaesthetics have been determined for a variety of marine (Soto and Burhanuddin 1995;Munday and Wilson 1997;Griffiths 2000;King et al 2005;Mylonas et al 2005;Cunha and Rosa 2006;Park et al 2008;Gullian and Villanueva 2009) and freshwater fish species (Keene et al 1998;Waterstrat 1999;Sladky et al 2001;Jayathilake et al 2003;Small 2003;Cooke et al 2004;Hoskonen and Pirhonen 2004;Roubach et al 2005;Kaiser et al 2006;Simões et al 2011;Morato-Fernandes et al 2013), as well as for freshwater life history stages of eels (Walsh and Pease 2002) and salmonids (Woody et al 2002;Iversen et al 2003;Hoskonen and Pirhonen 2004).…”

“…However, effective clove oil concentrations for anaesthetics have been published for only two Australian freshwater fish species, namely the tropical Western rainbowfish (Melanotaenia australis, Melanotaeniidae) (Castelnau 1875) (Young 2009) and the subtropical longfinned eel (Anguilla reinhardtii, Anguillidae) Steindachner 1867 (Walsh and Pease 2002). Interestingly, the effective concentrations for these two species are higher compared to non-Australian freshwater fish species from temperate (Keene et al 1998;Hoskonen and Pirhonen 2004), subtropical (Waterstrat 1999;Small 2003;Cooke et al 2004;Mylonas et al 2005;Morato-Fernandes et al 2013), and tropical regions (Sladky et al 2001;Jayathilake et al 2003;Roubach et al 2005;Kaiser et al 2006;Simões et al 2011). This highlights that freshwater biologists studying Australian fish cannot necessarily rely on clove oil concentrations determined for non-Australian fish, and that further work is needed to facilitate the collection, handling and transportation of Australian freshwater fish.…”