Temperature influence on the embryogenesis, survival and initial development ofMugil lizalarvae

Abstract

The Lebranche mullet (Mugil liza Valencienne, 1836) species is of great importance to artisanal and industrial fishing on the Atlantic coast of South America. In Brazil, it is the seventh most captured fish species, especially due to the rise in the export interest for the fish roe, known as the "Brazilian caviar" (Ferreira et al., 2011). However, artisanal fishing has been decreasing in the last 30 years, while industrial fishing has increased (MPA; MMA, 2015). Due to overfishing in recent years, the mullet was categorized as "near threatened" by the International Union for Conservation of Nature (IUCN) (MPA; MMA, 2015). A management plan for the sustainable use of this species was developed by the Brazilian government, considering its importance and vulnerability in Brazil's South and Southeast regions (IBAMA 2007). In this context, the need arises to establish successful cultivation procedures for this species.The Lebranche mullet has a variety of characteristics that facilitate its commercial rearing, such as high adaptability to wide temperature and salinity ranges, and acceptance of artificial diets (Carvalho et al., 2019). Temperature is one of the most important environmental variables. It can affect not only ontogeny during the first larval stages, but also the metabolism, oxygen consumption, growth, weight, yolk sac and body size of the marine organisms (Imsland et al., 2019;Jian et al., 2003;Neelmani et al., 2019). An increase in temperature can accelerate larvae development and change morphological characteristics, such as development of the pectoral fin, mouth opening and eye pigmentation (Fukuhara, 1990;Green & Brown, 2013).Weight and standard length are often used to evaluate larvae growth rate. However, other methods such as protein content, amount of energy amount and nucleic acid analysis (RNA/DNA ratio) can provide more accurate data (Buckley et al., 2008;Perez-Dominguez & Dahm, 2011). The RNA/DNA ratio has been accepted

Temperature influence on the initial development of Sardinella brasiliensis larvae

“…In S . brasiliensis larvae, the RNA/DNA ratio was stable in all the treatments, similar to what was found for Mugil liza , which could be related to the larval development time and its nutritional state (Angelo et al, 2021). The Brazilian sardine cultivated in laboratory shows that the RNA/DNA ratio decreases rapidly when the larvae are exposed to high temperatures and reach the minimum necessary only for survival (del Bianco Rossi‐Wongtschow et al, 2003).…”

“…There is a direct relationship between temperature and the rate of absorption of energetic reserve (Angelo et al, 2021). Both the yolk sac and the oil globule were not fully consumed when the larvae opened the mouth, and it was the time where the exogenous feeding would start.…”