Desenvolvimento de larvas de Steindachneridion sp. em diferentes condições de refúgio e luminosidade

Abstract

Resumo -Avaliou-se a influência da luminosidade e do uso de refúgios no desenvolvimento inicial de larvas de surubim do Iguaçu (Steindachneridion sp. Garavello) (Siluriforme: Pimelodidae). Utilizaram-se 1.000 larvas com peso e comprimento inicial de 62,2 mg e 18,02 mm, respectivamente, distribuídas em 20 aquários de 35 L, durante 22 dias. Os tratamentos consistiram dos ambientes: escuro sem refúgio, claro com refúgio artificial, escuro com refúgio artificial, claro com refúgio natural e claro sem refúgio, com quatro repetições cada, distribuídos em delineamento inteiramente casualizado. As larvas receberam a mesma alimentação em todos os tratamentos. As melhores taxas de sobrevivência foram verificadas nos ambientes: escuro sem refúgio, claro com refúgio natural e claro sem refúgio, com 84, 76 e 70%, respectivamente. O melhor desenvolvimento das larvas ocorreu em ambiente escuro e sem refúgio. O tratamento escuro com refúgio artificial apresentou diferenças significativas em relação à sobrevivência e ao peso final dos outros tratamentos, com grande heterogeneidade quanto ao peso. Ambientes escuros e sem refúgios são os mais adequados para o desenvolvimento inicial de larvas de surubim do Iguaçu.Termos para indexação: comportamento larval, larvicultura. Development of larvae of Steindachneridion sp. under different conditions of refuge and luminosityAbstract -The influence of luminosity and of the use of refuges on the initial development of Steindachneridion sp. Garavello (Siluriforme: Pimelodidae) larvae was evaluated. A thousand larvae 18.02 mm high and 62.2 mg weight were used in an entirely randomized design, with five treatments and four replicates, in 35 L-aquarium during 22 days. The treatments consisted on the following environments: darkness without refuges, clear with artificial refuge, darkness with artificial refuge, clear with natural refuge and clear without refuge. All larvae received the same feeding during the experiment. The best survival rates were found for darkness without refuges, clear with artificial refuge and clear without refuge, with 84, 76 and 70%, respectively. The best development was in darkness and without refuges. The treatment darkness with artificial refuge provided significant differences in relation to the other treatments as far as survival and weight are concerned, showing high heterogeneity for weight. Environment without refuges are the most appropriate for the larval development of this specie.Index terms: larval behaviour, larviculture. IntroduçãoMuitas espécies de peixes da região neotropical apresentam grande potencial para pesca e criação. Entre elas, os grandes siluriformes, como o pintado (Pseudoplatystoma corruscans) e o cachara (Pseudoplatystoma fasciatum) apresentam grande produção pesqueira. Essas e outras espécies, como o jaú (Paulicea luetkeni), foram muito afetadas pela sobrepesca e por outros impactos antrópicos. Agostinho & Zalewski (1996) afirmam que os represamentos e a destruição de ambientes utilizados na reprodução e no desenvolvimento de juvenis c...

Effect of photoperiod on locomotor activity, growth, feed efficiency and gonadal development of Nile tilapia

“…Red tilapia hybrids (O. mossambicus × O. niloticus and O. niloticus × O. mossambicus) exhibit feeding activity during the day, with peak feeding at dusk (Yousuf Haroon et al, 1998;Zav'yalov & Lavroviskii, 2001). Moreover, adult Nile tilapia (Oreochromis niloticus) exposed to a photoperiod of 12L:12D have shown higher feed intake and feeding activity during the light period when fed with automatic-demand feeders (Toguyeni et al, 1997;Fortes-Silva et al, 2010). The results of these studies confirm the role of photoperiod on feed intake, showing tilapia feeding behaviour to be predominantly diurnal.…”

“…However, Adewolu et al (2008) showed that fingerlings of African catfish, Clarias gariepinus, had better survival rates when reared under a photoperiod of 0L:24D. The longer survival in this condition can also be attributed to the feeding habit of this species, which feeds comfortably in the dark (Adewolu et al, 2008), dwelling in general, in river bottoms where the incidence of light is low (Feiden et al, 2006). These differences in the survival of different species can be attributed to the extreme variation in the preferred photoperiod, which is species-specific and depends on the stage of development (Britz & Pienaar, 1992;Silva-Garcia, 1996;Boeuf & Bail, 1999;Adewolu et al, 2008).…”

Influence of fish farming in net cages on phytoplankton structure: a case study in a subtropical Brazilian reservoir

“…Surubim do Iguaçu is an endemic species, restricted to the lower level of Iguaçu River (it appears only downstream of Segredo reservoir) and it is considered at risk of extinction (Feiden et al, 2006). In order to feed the fish, commercial ration of extruded type has been used.…”

Embryonic development and larval stages of Steindachneridion parahybae (Siluriformes: Pimelodidae): implications for the conservation and rearing of this endangered Neotropical species

“…Furthermore, reproductive status of broodstock when reared under different rearing systems and hormonal treatment (hormone stimulation techniques to induce ovulation and spermiation) of Pimelodidae species were also described (Batlouni et al, 2006;Andrade et al, 2010;Romagosa, 2010). On the other hand, considering the number of species and their threatened situation, similar to the genus Steindachneridion, there is little descriptive information on reproduction and early development stages of this genus, such as: S. melanodermatum (Ludwig et al, 2005;Feiden et al, 2006); S. scripta (Adamante et al, 2007;Zaniboni-Filho et al, 2008), and no information is available to S. parahybae. According to Feiden et al (2006), it is very important to study embryos and larvae development, within two main goals, conservation and commercial fish farming.…”