Idade, crescimento e duração larval de três espécies de lutjanídeos no Parque Nacional Marinho dos Abrolhos, Bahia - Brasil.

Abstract

The age and daily growth of fish are recorded through the deposition of increments in their otoliths, which are concretions formed by the precipitation of substances present in the endolymphatic fluid, mainly calcium carbonate (CaCO3). Faced with the need to fill in some gaps in knowledge about the occurrence and duration of the initial stages of the life cycle for the species of red in the Abrolhos bank (southern Bahia), the objective of this work was to describe the growth rates, age and and the pelagic larval duration period of three Lutjanidae species during the larval pre-settlement phase, in the region of Banco dos Abrolhos. Postlarvae capture was performed with CARE® type light traps. At the Marine Ecology and Conservation Laboratory (LECOMAR) the samples were measured, weighed, identified and dissected. The pair of Lapilii otoliths were extracted, embedded in epoxy resin and photographed for age estimation by counting growth increments. To ensure accuracy in age estimation, three replicate readings were performed independently of the daily increments from cross-sections of the otoliths. 153 larvae of the 3 species of red were identified and dissected to remove the otoliths, 117 specimens had their otoliths removed “without apparent damage” and after the thinning procedure 69 otoliths were viable to estimate the age, being 15 Lujanus analis, 25 from Lutjanus jocu, and 29 Lutjanus synagris. Together, the specimens presented individuals with total length (TC) between 16.14 mm – 24.76 mm, otolith radius lapilli between 55.51 μm – 106.58 μm, total age of individuals at capture between 21 and 39 days. Settlement marks were found for the three species and the average period of time that the larva remained in the pelagic environment (PLD) for L. analis was 24 days in the Parcel dos Abrolhos (PAB) and 26 days in the Abrolhos Archipelago (AB ), L. jocu was 26 days (PAB) and 25 days (AB) and for L. synagris 24 days (PAB) and 27 days (AB). There was a somatic growth directly proportional to the otolith growth. L. jocu was the species that presented the highest daily growth in relation to the other species. There was a strong relationship between the spawning period and the lunar cycle, with individuals of the 3 species spawning close to the full and waning moons. The 3 species are using the Abrolhos Bank as a larval settlement site, demonstrating plasticity when using different habitats throughout their lives, which is the first record of the use of the Abrolhos Bank as a nursery area by this family