Oocyte development and fecundity type of the Brazilian Snapper Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae)

Abstract

Lutjanid species exhibit multiple spawning behaviour during an extended spawning season in warm months, asynchronous oocyte development and indeterminate fecundity. Although early studies have contributed to knowledge of the reproductive cycle of many species within the group, they have not considered aspects about the number of cortical alveoli oocyte stage throughout maturity phases along spawning season. The latter aspect is also considered very important to confirm indeterminate fecundity hypothesis. In the present study, were analyzed 154 Brazilian snapper Lutjanus alexandrei female gonads obtained from artisanal fisheries in Pernambuco State (Brazil) between October 2010 and March 2011. Were measured oocyte size frequency distribution for maturity phases (developing, spawning capable and actively spawning), and oocyte development stage (unyolked oocytes, cortical alveoli, primary, secondary and tertiary vitellogenic oocytes and hydrated oocytes), and also the oocyte stage frequency during spawning season. The frequency of cortical alveoli oocyte stage was constantly found in the spawning period (>37%), showing slight variation throughout maturity phases. The absence of gap in the oocyte size frequency distribution between primary and secondary oocyte growth stages during spawning season is a strong indicator of continuous oocyte recruitment from reserve stocks. In addition, co-occurrence of tertiary vitellogenic oocytes, hydrated oocytes, post-ovulatory follicles and yellow-brown bodies in the histological sections of ovaries reinforce indeterminate fecundity hypothesis.Keywords: multiple spawning, asynchronous development, ovulation.Desenvolvimento ovocitário e tipo de fecundidade da baúna de fogo Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae) ResumoOs lutjanídeos apresentam um comportamento de desovas parceladas ao longo de uma extensa estação reprodutiva nos meses mais quentes do ano, desenvolvimento assincrônico dos ovócitos e padrão de regulação de fecundidade indeterminado. Embora muitos estudos anteriores tenham contribuído no conhecimento do ciclo reprodutivo das espécies do grupo, não foram considerados os aspectos relacionados ao percentual dos ovócitos em estágio de cortical alveoli entre as fases de maturidade sexual durante a estação reprodutiva. Este último aspecto, considerado importante para confirmação da hipótese de fecundidade do tipo indeterminada. Para isso, no presente trabalho foram analisadas 154 gônadas de fêmeas da baúna de fogo Lutjanus alexandrei obtidas da pesca artesanal em Pernambuco entre o período de outubro de 2010 a março de 2011. Foram mensurados os diâmetros dos ovócitos nas fases de maturidade sexual (desenvolvimento, capaz de desovar e ativamente desovando), e para todos os estágios ovocitários (ovócitos pre-vitelogênicos, cortical alveolar, vitelogênese primária, secundária, terciária e ovócitos hidratados), e avaliada a frequência de ocorrência ao longo do período de desova. O percentual de ovócitos em estágio cortical alveoli permanece...

Effects of dietary fish oil and corn oil on gonadosomatic and hepatosomatic index, gonadal histology, 17β‐oestradiol level and fatty acids profile of mahseer ( Tor tambroides ) broodstock in captivity

“…Significant differences between treatments were determined using Duncan's post hoc test, and the level of significance difference was set at p < .05. When the data were not normally distributed, that is data for oocyte diameter analysis, non-parametric Kruskal-Wallis test was used while the distribution of oocyte diameter between anterior and posterior were tested with Mann-Whitney (p < .05) test to verify statistically significant differences (Fernandes et al, 2016). All data were analysed using IBM SPSS Statistics software (version 23).…”

“…Lutjanus alexandrei (Fernandes et al, 2016), the skipjack, Katsuwonus pelamis (Grande et al, 2012) and common carp, Cyprinus carpio (Smith & Walker, 2004) where continuous oocyte recruitment into the standing stock of developing oocytes were observed. Based on the variety of oocyte diameter distribution and presence of all stages of oocytes in the gonad, female T. tambroides can be categorized as indeterminate spawners (Fernandes et al, 2016;Grande et al, 2012) where they can spawn in batches with continuous oocytes recruitment (Ingram et al, 2005;Ismail et al, 2011).…”

“…Tissues section were examined for gonad developmental stages based on the oocyte size and frequency distribution (Ismail et al, 2011). In order to assess the oocyte size and frequency distribution, 100 oocytes (from histological analysis picture) were randomly measured by using ImageJ software for each specimen (n = 3) from two sampling sides (anterior and posterior) of gonads, using the methodology adapted from Fernandes et al (2016), Grande et al (2012) and West (1990). When the oocyte diameter was measured as the average of the major and minor axes, the limit for each stage was identified as the limits of confidence intervals which did not overlap the mean value to segregate the oocyte stages.…”