Oocyte Size Frequency Distribution Research Articles

Reproductive Biology of the Hybrid Coptodon guineensis x Coptodon zillii within Two Marginal Lagoons Invaded by Macrophytes in South Eastern of Côte d`Ivoire

Hybrids of Coptodon guineensis x Coptodon zillii are omnivorous species with a phytophagous tendency found in most of water bodies of Côte d`Ivoire. This study aims to better understand its reproductive biology and possible influence of macrophytes on the breeding season. A total of 608 fish were caught monthly from September 2017 to August 2019. The overall sex-ratio showed significant predominance of females in Ono (1:1.37; χ² = 7.10; P<0.05) and Kodjoboue (1:1.84; χ² = 28.62; P<0.05) lagoons. The sexual maturity recorded in Ono lagoon for males (148.2 mm, SL) and females (145.3 mm) was slightly higher than that of males (144.4 mm, SL) and females (141.8 mm) in Kodjoboue lagoon. March and August–October (Ono lagoon) and February and July–September (Kodjoboue lagoon) were the most intensive spawning months. The absolute fecundity was higher in Ono lagoon (1472–6116 oocytes) than in Kodjoboue lagoon (1676–4210 oocytes), indicating a better food supply due to the high abundance of macrophytes in Ono lagoon. Oocyte size frequency distributions show oocytes of different sizes, indicating more than one spawning within a reproduction season. These findings might facilitate future studies establishing its potential production and its exploitation and management.

Life History Traits, Elasticity Analyses, and Phenotypic Plasticity of Squaliobarbus curriculus in the Pearl River Estuary, China

Squaliobarbus curriculus, commonly known as red-eye fish, is widely distributed in East Asia. It is one of the important aquatic germplasm resource and economic species in the Pearl River. To give suggestions for better protection and management, we investigated its life history and conducted elasticity analyses. Samples (n= 451) were collected between 2016 and 2017 from the western Pearl River estuary. There were no significant differences between the length-weight relationships of females and males (W= 0.00001SL3.121). The von Bertalanffy growth function was Lt= 553.2 [1 − e−0.111(t+1.009)]. The estimated length at 50% sexual maturity for females was 209.6 and 200.0 mm for males, both at 3 years of age. Oocyte size-frequency distribution suggested batch spawning. Fecundity ranged between 9,407 and 175,086 eggs per fish (mean = 51,040, or 143.9 eggs/g of fish weight). To better understand the ecological phenotypic plasticity ofS. curriculuswe conducted meta-analyses on all available life history data for this species. Our results showed that the standard lengths at ages 2 and 3 in the estuary were significantly smaller than in the upper reaches of the Pearl River basin, and there were also obvious differences in fecundity and oocyte size. For more, the standard lengths at ages 2 and 3 were correlated negatively with latitude. Elasticity analysis showed that juveniles’ (aged 1–3) survival had the largest contribution to the population growth rate, which suggests that management efforts should focus on the early life stages.

Ovarian dynamics, batch fecundity and spawning phenology of the lessepsian migrant Etrumeus golanii DiBattista, Randall & Bowen, 2012 (Clupeidae: Dussumieriinae)

The Golani’s round herring Etrumeus golanii is an Erythraean small pelagic fish (lessepsian migrant) that entered into the Mediterranean Sea through the Suez Canal. It has expanded its distribution from the east to the western Mediterranean with well-established local populations. We investigated basic aspects of its reproductive biology off the island of Crete (eastern Mediterranean) using ovarian histology and analysis of oocyte size-frequency distributions. The species exhibited a protracted breeding period (winter to early summer), with all ovaries examined during the main spawning season having markers of recent (postovulatory follicles, POFs) or imminent spawning (advanced oocyte batch in germinal vesicle migration or hydration). The advanced batch (AB) increased rapidly in size and was fully separated from the remainder, less developed oocytes in 95% of females with “old” POFs (POFs with signs of degeneration) and all females in final maturation. The growth of the subsequent batch (SB) was arrested at sizes <630 µm until full maturation of the AB. Mean diameter of hydrated oocytes ranged from 1181 to 1325 µm and relative batch fecundity was low ranging from 56 to 157 eggs g-1. The simulation of a coupled hydrodynamic/biogeochemical model (POM/ERSEM) provided evidence that E. golanii takes advantage of the seasonal cycle of planktonic production to reproduce and exhibits monthly changes in batch fecundity that appear to be closely related with the seasonal cycle of mesozooplankton concentration.

Invariant Gametogenic Response of Dominant Infaunal Bivalves From the Arctic Under Ambient and Near-Future Climate Change Conditions

Arctic marine ecosystems are undergoing a series of major rapid adjustments to the regional amplification of climate change, but there is a paucity of knowledge about how changing environmental conditions might affect reproductive cycles of seafloor organisms. Shifts in species reproductive ecology may influence their entire life-cycle, and, ultimately, determine the persistence and distribution of taxa. Here, we investigate whether the combined effects of warming and ocean acidification based on near-future climate change projections affects the reproductive processes in benthic bivalves (Astarte crenata and Bathyarca glacialis) from the Barents Sea. Both species present large oocytes indicative of lecithotrophic or direct larval development after ∼4 months exposure to ambient [<2°C, ∼400 ppm (CO2)] and near-future [3–5°C, ∼550 ppm (CO2)] conditions, but we find no evidence that the combined effects of acidification and warming affect the size frequency distribution of oocytes. Whilst our observations are indicative of resilience of this reproductive stage to global changes, we also highlight that the successful progression of gametogenesis under standard laboratory conditions does not necessarily mean that successful development and recruitment will occur in the natural environment. This is because the metabolic costs of changing environmental conditions are likely to be offset by, as is common practice in laboratory experiments, feeding ad libitum. We discuss our findings in the context of changing food availability in the Arctic and conclude that, if we are to establish the vulnerability of species and ecosystems, there is a need for holistic approaches that incorporate multiple system responses to change.

Temporal variability in gametogenesis and spawning patterns of crown-of-thorns starfish within the outbreak initiation zone in the northern Great Barrier Reef

Population outbreaks of the coral-eating crown-of-thorns starfish (CoTS) have resulted in extensive coral mortality on reefs in the Indo-Pacific region and is considered one of the major contributors of significant declines in coral cover in Australia’s Great Barrier Reef (GBR). Effective management of CoTS outbreaks rely on improved understanding of the drivers of individual and population-level differences in reproductive patterns, particularly those factors that may contribute to step-changes in reproductive success, such as the timing and synchronicity of spawning. This study investigated gametogenesis and spawning patterns in a persistent population of CoTS at one reef within the putative initiation zone where outbreaks appear to start in the GBR. We examined variation in the progression of gametogenesis and spawning patterns over two distinct spawning seasons (2013–2014, 2014–2015), using a variety of methods: macroscopic examination of gonads, assessment of monthly changes in the gonadosomatic index, analysis of histological sections of ovaries and testes, and comparison of the size-frequency distribution of oocytes. These methods yielded consistent results, which revealed striking variation in the timing of maturation and gamete release between two summer spawning seasons, possibly depending on local environmental conditions. The optimal temperature for gametogenesis and spawning occurred when seawater temperature exceeded 28 ℃. Gradual increases in temperature (to > 28 ℃) over spawning months in 2013–2014 caused ‘batch/dribble’ spawning, while abrupt increases in temperature in 2014–2015 caused synchronous ‘all-at-once’ spawning. During more rapid warming events in the typical summer spawning period, CoTS may exhibit greater synchronicity in their reproductive capacity, which may help seed outbreaks. This work advances our understanding of the mechanisms surrounding periodic fluctuations in CoTS densities and improves predictions on how this corallivorous predator will respond to environmental perturbations due to climate change.

Reproductive development and maturity stage benchmarking in a freshwater teleost ruffe Gymnocephalus cernuus L. in Loch Lomond.

A wide range of classification schemes has been developed to describe reproductive development and stages in teleosts. These have been rationalised for clarity in recent years by Brown-Peterson et al. (Marine and Coastal Fisheries, 2011, 3, 52-70) and the WKASMSF (ICES, Report of the workshop for advancing sexual maturity staging in fish (WKASMSF), 2018) working groups. These have largely benchmarked classification schemes with examples from seawater fishes but have not been routinely applied to freshwater species. In addition, classification schemes developed to assess maturation of fish ovaries are either macroscopic and can be used in the field or histological for laboratory-based studies, and the two have rarely been coupled in the same classification scale or study. The present study reviews published maturation classifications for application to a freshwater teleost, ruffe Gymnocephalus cernuus L., sampled monthly over three annual cycles in Loch Lomond at locations in the extreme north and south ends of the loch. The gonado-somatic index and size frequency distribution of oocytes were used to verify the annual reproductive cycle and spawning of several egg batches. The study showed that a paired modified Percid scale (Treasurer & Holliday, Journal of Fish Biology, 1981, 18, 359-376) and the Rinchard scale (Rinchard & Kestemont, Journal of Fish Biology, 1996, 49, 883-894) gave an improved macroscopic and histological description of maturation compared with and benchmarked against previous ovarian developmental classifications for G. cernuus. The attributes of these various classifications are benchmarked and compared with the Brown-Peterson and WKMATCH scales, and the merits of these new notations are examined.

A comprehensive description of oocyte developmental stages in Pacific halibut, Hippoglossus stenolepis.

Accurate characterization of oocyte development is essential to understanding foundational aspects of reproductive biology and successful management of Pacific halibut (Hippoglossus stenolepis). Here this study provides complete histological descriptions for eight oocyte developmental stages in addition to postovulatory follicles and demonstrates the potential for oocyte size frequency distribution to act as a proxy for ovarian developmental stage and future maturity assessments. Importantly, it provides the first histological evidence that Pacific halibut have a group‐synchronous ovarian developmental pattern with determinate fecundity and support for their batch‐spawning strategy.

Development of a new \u2018ultrametric\u2019 method for assessing spawning progression in female teleost serial spawners

The collection and presentation of accurate reproductive data from wild fish has historically been somewhat problematic, especially for serially spawning species. Therefore, the aim of the current study was to develop a novel method of assessing female spawning status that is robust to variation in oocyte dynamics between specimens. Atlantic cod (Barents Sea stock) were used to develop the new ‘ultrametric’ method, that is based on the progressive depletion of the vitellogenic oocyte pool relative to the rather constant previtellogenic oocyte (PVO) pool. Fish were subsequently partitioned into one of four categories that accurately reflected changes in their oocyte size frequency distribution characteristics and gonadosomatic index throughout spawning. The ultrametric method overcomes difficulties associated with presence of bimodal oocyte distributions, oocyte tails, lack of clear hiatus region, and presence of free ova, and can be implemented at a single sampling point. Much of the workflow is fully automated, and the technique may circumvent the need for histological analysis depending on the desired outcome. The ultrametric method differs from the traditional autodiametric method in that PVOs can be separated by ultrasonication and then enumerated, and ovarian homogeneity is not a mandatory requirement per se. The method is designed for determinate spawners but might be extended to include indeterminate spawners.

Reproductive cycle of Ophiopholis mirabilis (Echinodermata: Ophiuroidea) in Zhangzi Island area, northern Yellow Sea

Ophiopholis mirabilis is a common species with a high population density on the western coasts of the northern Pacific Ocean. The number of O. mirabilis has been increasing recently in the scallop aquaculture zone (the Zhangzi Island area, northern Yellow Sea) in China. To explore the mechanism of its population variation, the reproductive cycle of O. mirabilis was investigated in this area (39°04’N; 122°51’E) from February 2017 through January 2018 and determined by the monthly gonad index (GI), histological examinations of the gonads and the oocyte size-frequency distribution. O. mirabilis had a clear annual reproductive cycle that was synchronous between males and females. Sea temperature and food availability played important roles in O. mirabilis reproduction. The GI value was less reliable for determining reproductive activity in O. mirabilis because the nutritive tissues within the gonads may be utilized to synthesize gametes, leading to a decrease in GI during maturation. The histological results also show that abundant nutritive phagocytes were present in the gonads of O. mirabilis, which, together with the germ cells, affected the weight of the gonads. In addition, the mature oocytes of O. mirabilis were relatively small (75–150 µm), indicating that the larval development was planktotrophic. This study provided insights into the reproductive patterns and biology of O. mirabilis and is an essential basis for the quantity control of this species in aquaculture areas.

Ovarian dynamics in picarel (Spicara smaris, L., Sparidae) and implications for batch fecundity and spawning interval estimation

This study assessed ovarian dynamics in picarel and examined how it can be implemented in routine calculations of batch fecundity and spawning interval. Samples of picarel were collected in Saronikos Gulf, Greece, and ovaries were examined through both histological and whole mount procedures. Three different and independent approaches were applied to assess ovarian modality: (a) the multimodal analysis in oocyte size frequency distributions (OSFD), (b) the histological grouping of oocytes to different cohorts and (c) the ratio of the total number of secondary growth oocytes to the oocytes of the advanced mode. The output from all three methods was in good agreement to each other, suggesting that picarel contains in average 3 to 5 oocyte cohorts throughout the spawning period. Further study of OSFD revealed that the advanced oocyte mode (AM) was clearly distinct since the onset of the spawning season in February and it either partially overlapped with or was separated from smaller oocytes. The gravimetric estimate of relative fecundity of the advanced mode (RFAM) in hydrated females equaled to 336 oocytes g−1 (± standard error16.23) and was comparable to the RFAM from other stages, with and without hiatus in the OSFD. These results show that batch fecundity in picarel can be estimated even in non-hydrated females. Considering the temperature dependent duration of posyovulatory follicle (POF) degeneration, the prevalence of recent spawning markers and their co-occurrence with imminent spawning markers, we conclude that spawning interval in picarel at peak spawning should be between 2 and 4 days.

Reproductive parameters of Atlantic chub mackerel Scomber colias in M'diq Bay, Morocco

AbstractReproductive biology of Atlantic chub mackerel (Scomber colias) was studied based on samples from commercial catches in M'diq Bay, Morocco. Females predominated in the total catch (54%), their size at first maturity being 19.19 ± 0.43 cm TL. A minimum landing size (MLS) of 21 cm is suggested. The oocyte size frequency distribution and histological analysis confirmed that S. colias is a species with an indeterminate fecundity. The batch fecundity was estimated as 18,452–131,642, with a mean of 60,022 oocytes. The relative batch fecundity was 157–360, with a mean of 279 eggs g−1.

The ovarian development, fecundity and hypothesis on spawning pattern of common cuttlefish Sepia officinalis off Mauritania

Cephalopod species have evolved highly flexible spawning strategies, but the extent to which spawning strategy adopted is inextricably linked to the ovarian development. To address the spawning strategy of common cuttlefish Sepia officinalis outside northwest Africa, an analysis of ovarian development and hypothesis on spawning pattern was undertaken for specimens (mantle length of 126–270 mm from stages II to IV) collected from commercial catches off Mauritania during summer months of July and August 2015. It was found that the mature/spawning female S. officinalis covered a wide range of body size, being 148–270 mm ML, and showed non-stop food intake. The gonadosomatic index (GSI) increased steadily with maturity from 2.13% to 13.22%, being higher mean value of 8.65 ± 1.69% at mature/spawning stage. Potential fecundity (PF) increased with female size from 1306 to 3376 oocytes (mean 2327 ± 554.47). The oocytes were developing asynchronously as evidenced by the dominant small oocytes throughout sexual maturation and a bimodal size-frequency distribution of yolk oocytes for animals at maturing and mature/spawning stages. The mature oocytes in ovaries of mature/spawning individuals consistently accounted for less than 1% PF. There were about 770–1966 viable eggs that would be released during the spawning season. These evidences indicate that S. officinalis off Mauritania undergo the asynchronous ovarian development, and adopt a complementary spawning strategy falling somewhere along a continuum between intermittent and multiple spawning to adapt to the nutrient-rich Mauritanian upwelling system.

REPRODUCTIVE ASPECTS OF THE TROPICAL ABALONE, HALIOTIS ASININA, FROM SOUTHERN LOMBOK WATERS, INDONESIA

The main objective of this study was to determine reproductive strategy including major spawning season of tropical abalone (Haliotis asinina) from southern Lombok waters, Indonesia. Gonad bulk index, maturity stages and oocyte size frequency distribution were applied to document gonadal development and major spawning season. The results of this study show that H. asinina in southern Lombok waters displayed year-round spawning with a high proportion occurring in August - November, when gonad index dropped to a lower level and high proportion of partly spawned and/or spent ovaries occurred in the population. Gonad development and spawning in males and females occurred synchronously. The correlation between gonadal development and environmental factors are described and discussed.

Oocyte size distribution reveals ovary development strategy, number and relative size of egg batches in lumpfish (Cyclopterus lumpus)

The reproductive biology of fishes impact many other components of their life history, and can influence their vulnerability to fisheries, therefore for more informed management, a good understanding is essential. For lumpfish (Cyclopterus lumpus), a semi-pelagic species found across the north-Atlantic and targeted by fishers for their roe, comprehensive knowledge of this aspect of their life history is still lacking. Through a combination of regular sampling from scientific surveys and fisheries and modern methodology in fish reproductive biology, we investigated the ovary development of lumpfish throughout vitellogenesis. The results showed that ovaries of lumpfish had a wide range of oocyte sizes and that lumpfish are a determinate, batch spawner with ovary development taking at least 8 months. They spawn a maximum of two batches per season with a similar number of eggs in each batch. Unusually for a determinate batch spawner, the two batches were easily distinguished within the ovary prior to ovulation. Average egg size ranged from between 2050 and 2500 µm, with larger fish having larger eggs, and the egg diameter of the second batch being on average 1.6% smaller than the first. Lumpfish were documented as spawning over a 4-month period, but it is likely that spawning occurs over a greater period. A macroscopic and oocyte size frequency distribution (OSFD) scale for lumpfish is presented which can be used for future studies of lumpfish.

Oocyte recruitment and fecundity type in fishes: Refining terms to reflect underlying processes and drivers

AbstractOnly with new technology and the ability to simulate systems are we beginning to understand fish reproductive processes at the individual scale over time. Traditionally, oocyte recruitment and fecundity type in fishes have been based on a “snapshot” approach, that is a histological micrograph and/or oocyte size frequency distribution of a spawning capable female has been assumed to indicate oocyte recruitment processes over time. This has important implications as the asynchronous and group‐synchronous oocyte recruitment patterns are associated with indeterminate and determinate fecundity types, respectively, and thus affect estimates of reproductive potential and spawning biomass (if using egg production methods). However, a historic review of these terms revealed that they are not applied consistently, with the same oocyte recruitment pattern often assigned to both of these by different scientists. The intent of this study is to develop a conceptual model of oocyte recruitment processes over time, key drivers, and resulting “snapshots” to refine oocyte recruitment terms, definitions, and the methods needed to identify them.

Reproductive characteristics of northern pike, Esox lucius (Actinopterygii: Esociformes: Esocidae), in the Anzali Wetland, southwest Caspian Sea

Background. Temporal variability in fish reproductive features is influenced by environmental and spatial variations. Given the wide distribution of northern pike, Esox lucius Linnaeus, 1758, in the northern hemisphere, important reproductive features such as the initiation of the spawning activity are likely to vary with latitudinal gradients. The overall goal of the presently reported study was to answer basic questions regarding the reproductive biology of the pike and to discuss changes in the timing of the onset of spawning activity in relation to geographical locations and the water temperature in the Anzali Wetland compared to higher latitudes. Materials and methods. Monthly samples (537 specimens in total) were collected from the Anzali Wetland (southwest of the Caspian Sea) from July 2012 through July 2013. Samples were macro- and microscopically examined, and their maturity stages were identified, so that spawning season, monthly distribution of maturity stages, oocytes development, spawning strategy, length at 50% maturity, and fecundity were estimated. Results. The gonadosomatic index, oocyte size-frequency distribution, and histological examination suggested a relatively short spawning season, from February through March. The short annual spawning period and the oocyte size-frequency distribution demonstrated that pike is a total spawner with group synchronous oocyte development. The length at 50% maturity was 28.5 and 33.9 cm FL for males and females, respectively. Absolute fecundity values ranged from 4423 to 48471 oocytes, with mean (± standard error) of 16481 ± 2705 oocytes and the relative fecundity was estimated as 26.9 ± 1.6 oocytes per gram of mature female. Conclusion. The most important findings of this study are: the earlier initiation and relatively shorter duration of the reproductive activities of pike in the south Caspian region compared to northern geographical regions. The results emphasize the need for specific management strategies based on seasonal measures for pike such as: fish size limits, limitation of catches during the spawning season, limitation of the boat number, and closure of the spawning area during spawning months.

Yolked Oocyte Dynamics Support Agreement between Determinate- and Indeterminate-Method Estimates of Annual Fecundity for a Northeastern United States Population of American Shad.

Reports of American shad fecundity identify two important themes regarding egg production in fishes. First, geographic variation occurs and is biologically meaningful. Shad annual fecundity decreases with increasing latitude, but predicted lifetime fecundity does not, because of a counter-gradient of survival probability, all of which can explain the adaptive significance of natal homing. Second, the appropriate method of measuring fecundity depends on the pattern of oocyte development. Historically, the relatively simple determinate-fecundity method was used; however, a recent study in a Virginia river indicates that this method may be biased, requiring the more complicated indeterminate method. We address both themes with collections from the 2015 shad spawning run in the Connecticut River, USA. Criteria for using a determinate method were satisfied for this northern population: 1) a size gap evident in the oocyte size frequency distribution, indicating group-synchronous development of yolked oocytes; 2) a decline, early in spawning, in the standing stock of yolked oocytes; and 3) low levels of atresia at the end of spawning. The determinate-method estimate of American shad annual (2015) fecundity (303,000 ± 73,400; mean ± sd) overlapped historic estimates for this and a neighboring river. The indeterminate-method estimate of annual (2015) fecundity (311,500 ± 4,500 sd) was not significantly different from the determinate-method estimate (Student’s t-test, P > 0.05). In contrast, indeterminate-method estimates of annual fecundity for a Virginia population were twice as high as that measured by the determinate method in the past. This can all be explained by fundamentally different patterns of oogenesis (i.e., group synchrony versus asynchrony with respect to yolk development) at different latitudes. American shad, which is distributed within its native range from the Canadian maritimes to Florida, USA (50–30°N), may be particularly well suited to evaluate intra-specific variation in oocyte development, a relatively unexplored life history trait.

Oocyte batch development and enumeration in the European anchovy (Engraulis encrasicolus)

An alternative method to the traditional hydrated oocyte (HO) method has been evaluated for the Sicilian anchovy, Engraulis encrasicolus. The method is based on the processing of ovarian whole mount images and the identification of the spawning batch in oocyte size frequency distributions and shows the advantage that it can be applied to various oocyte stages rather than strictly to the HO stage. Despite the peculiar elliptical shape of anchovy oocytes, this image analysis technique was fully successful since the yolked stage appeared to perform equally to the HO stage for anchovy batch fecundity measurements.

Reproductive strategy of the invasive sharpbelly,Hemiculter leucisculus(Basilewsky 1855), in Erhai Lake, China

This study describes the reproductive strategy of the sharpbelly Hemiculter leucisculus, an invasive and dominant species in Erhai Lake in China with the goal of understanding how reproductive strategy contributes to its environmental adaptability and invasive potential. Specimens (n = 3583) were collected monthly or bimonthly from July 2009 to June 2011 (min: 114-Feb, max: 883-Aug), using gill nets (inner/outer mesh = 30/110 mm, stretched mesh). Gonads were removed, weighed and preserved for further (histological) analyses. Oocyte size-frequency distribution was continuous and had advanced vitellogenic oocytes with postovulatory follicles present in spawning females, both suggesting that sharpbelly is a multiple spawner with adhesive eggs. Spawning extended from April to September, with the peak period from May to August. Standard lengths (SL, cm) at minimal observed maturity/L50/L99.9 values were 4.6/5.6/10.5 for females and 5.1/5.5/7.5 cm for males, respectively. Females were over-represented (P < 0.01) in SL-classes over 9 cm and males completely absent from the 13 to 19 cm SL-classes. Overall sex ratio was highly significantly (P < 0.01) biased towards females (♀ = 1518, ♂ = 685, ♀/♂ = 2.21), however this was reversed in the spawning stock (8.3–16 cm, ♀ = 58, ♂ = 142, ♂/♀ = 2.45, P < 0.01). Batch spawning, a long spawning period, high male investment in reproduction and adhesive eggs all represent local adaptations in reproductive strategy that, along with other environmental factors, contribute to the invasion success of sharpbelly in Erhai.

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

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.