Reproductive biology of the armoured catfish Loricariichthys castaneus (Castelnau, 1855) in Lajes reservoir,southeastern Brazil

Sex ratio, gonadal development, breeding season and fecundity of the armoured catfish Loricariichthys castaneus were described to assess its reproductive strategy in a Brazilian tropical reservoir. In total, 226 specimens (199 females and 27 males) were captured from September 2005 to August 2006 and examined in the laboratory. Females outnumbered males and achieved sizes larger than 330 mm TL. Oocyte development, determined by histological analysis, was asynchronous with oocyte size, ranging from pre‐spawning (27–270 μm) to spawning (243–3460 μm), followed by a sharp decrease in the mean oocyte diameter postspawning (590–730 μm) as the spawning proceeded. Spawning occurred throughout most of the year, peaking in August–September and reaching a low in April–May, according to variations in GSI and frequencies of stages of gonadal development. Batch fecundity ranged from 242 to 833 vitellogenic oocytes (relative fecundity = 2.27 oocytes g^?1), averaging 483 oocytes, and was positively related to gonad weight (P = 0.00003). Oocyte diameters ranged from 0.027 to 5.59 mm, with vitellogenic diameters ranging from 2.08 to 5.59 mm. Continuous development of oocytes throughout the year suggests that L. castaneus presents indeterminate fecundity and is a batch‐spawner. These attributes, associated with parental care and a wide reproductive period, correspond to an equilibrium strategy that has proved to be effective in the Lajes reservoir.     

Comparative fecundity and oocyte size of Aristaeomorpha foliacea and Aristeus antennatus in the Greek Ionian Sea (E. Mediterranean) (Decapoda: Aristeidae)

Absolute and relative fecundity of 49 ripe gonads (from the cephalic and the abdominal sections of the same specimen) of Aristaeomorpha foliacea and 71 ripe gonads of Aristeus antennatus caught in the Ionian Sea (E. Mediterranean) and their oocyte size were studied. Both average absolute and relative fecundities estimated for A. antennatus were statistically higher than those estimated for A. foliacea; the average absolute fecundity of A. foliacea was 151 936 oocytes/female and that of A. antennatus was 200 472 oocytes/female and the average relative fecundity of A. foliacea was 5477 oocytes/g and that of A. antennatus was 9386 oocytes/g. Fecundity in both red shrimp species is linearly related to carapace length, body and gonad weight, although, the most precise estimation is provided by the relationship of body weight and fecundity. In the present study, the oocyte size (diameter, volume) of both species could be considered very large. In conclusion, A. foliacea shows lower fecundity than A. antennatus, having a lower ovogenetic activity, but it produces larger oocytes. This is in accordance with the highest value of the gonad weight and gonad volume of A. foliacea exhibited in relation to A. antennatus.     

Determination of batch fecundity in Uranoscopus scaber Linnaeus, 1758 from the Aegean Sea, Turkey

This work focuses on reproductive biology aspects of Uranoscopus scaber from the coast of the Aegean Sea. In total, 175 U. scaber specimens were collected in Izmir Bay using trawl nets from January to December 2005. The reproduction period according to gonadosomatic index (GSI) values extents from March to September, with a peak in May (6.32 ± 1.2). Oocyte diameters taken from 59 mature gonads ranged from 62 to 1860 μm. Maximum batch fecundity (BF) was 58091 (mean: 11556 ± 1445) in large oocytes in May, and 8408 (mean: 2821 ± 945) in hydrated oocytes in September. The BF increased with total length and body weight, excluding the ovaries. Total length (TL)–BF relationships and fish weight–BF relationships were BF = 0.0034TL^4.6248 (r = 0.47) and BF = 59.166W?3101 (r = 0.49), respectively, according to the oocyte size frequency method. There was a linear relationship between BF and fish size.     

Reproductive biology of Galaxias maculatus (Jenyns 1842) in the Río Ovando,a high‐latitude environment in southernmost Patagonia,Argentina

This study establishes the reproductive cycle, batch fecundity and oocyte diameter of a diadromic population of the puyen, Galaxias maculatus, in the Río Ovando, Tierra del Fuego, (54°S), at the southernmost limit of its distribution. Given the short ‘favourable season’ in relation to other populations of the species (in terms of temperature, photoperiod and food availability), the study also explores the trade‐offs between feeding and oocyte production and between phases of growth and reproduction. The reproductive cycle was analyzed by the monthly evolution of the proportion of gonadal maturity stages (determined from microscopic examination of the gonads). Oocytes were measured using a micrometric ocular scale and classified by diameter and morphological characteristics; absolute fecundity was established as the total number of hydrated oocytes per ovary. The studied population exhibits a repetitive spawning strategy, given the coexistence of post‐ovullatory follicles and hydrated oocytes in histological sections and the presence in ripe ovaries of an intermediate cohort of yolked oocytes ready for hydration. Individual fecundity is lower (1422 ± 422 oocytes/ovary) than in other puyen populations, but the egg production increases through individual repetitive spawnings during the protracted spawning period (from October to February). Females attain larger sizes than those of other South American populations (the largest female reaching 115 mm total length), maximizing its potential fecundity. The present paper contributes to the knowledge of the variability of reproductive traits of G. maculatus in relation to diadromic populations, given that the bulk of information in South America refers to landlocked populations.     

Reproductive strategy of the European perch,Perca fluviatilis Linnaeus, 1758 (Osteichthyes: Percidae) in the Anzali wetland,southwest Caspian Sea

Temporal variation in reproductive traits of geographically distributed fish is supposed to take place in response to the spatial and environmental variations. With regard to the wide distribution of the European perch in the northern hemisphere, important reproductive traits such as the initiation and duration of the spawning activity are likely to vary in different latitudinal gradients. In this study, reproductive biology of the European perch, Perca fluviatilis, is described, based on 324 specimens caught in the Anzali wetland (southwest Caspian Sea) between June 2008 and May 2009. The gonadosomatic index, oocyte frequency distribution and histological examination suggested a long vitellogenic process (October to February) and a short spawning season (January and February). The size‐frequency distribution of the oocytes showed that this perch is a species with group‐synchronous ovarian development. Ovarian development occurred only in one clutch of oocytes (700–900 μm oocyte diameter) with no indication of maturation of any subsequent clutch in the spawning season. The average of (realized) fecundity (±SD) was estimated to be 16177 ± 5846 eggs in late vitellogenic stage, which was lower than the potential fecundity (17188 ± 6917 eggs). Histological examination of the gonads revealed the existence of atretic oocytes in early vitellogenic stages (October and November). This investigation highlights the temporal variation in the initiation and duration of the reproductive activity of the European perch in this region compared to other geographical regions. The results emphasize the necessity of specific temporal management in fishing of European perch based on spatial differences in reproductive biology.     

Cyclic variations of gonad development of snow trout,Schizopyge niger from the river Jhelum of Kashmir Himalaya

The aim of the present study was to know the cyclic changes in gonadal maturation and to investigate the various developmental stages of oocytes and testicular germ cells of snow trout, Schizopyge niger. A total of 316 fish specimens were procured from three sites of river Jhelum during November 2016 to October 2017 and the histological analysis of their gonad was carried out. The results of the present study indicates that the male population was found significantly (p < 0.05) higher compared to female population and were reported as (1.6:1; M:F). The highest mean GSI value was recorded in male (12.24 ± 0.89) during the month of March and for female (13.74 ± 0.92) also in the month of March, which indicated that the gonadal development reached its peak during this month. The highest mean oocyte diameter was 1.04 ± 0.20 mm observed in March, showing that the oocyte reached its maturity during this month. Histological study of ovary revealed the evidence of vitellogenic yolk granule stage and ripe mature stage from December to April. While in case of male, four stages of spermatogenesis were distinguished and spermatozoa were highly abundant in the months of March and April. Mean ± SE of absolute fecundity was 3,224 ± 421 eggs and also, the relative fecundity was 69 egg/g body weight. Based on the results of GSI and the analysis of gonad histology, it was observed that the peak breeding season of S. niger occurred in the month of March. It was also noted that spawning period of this fish begins in the month of February and lasts till April with a peak breeding season in the month of March. The present study will provide a baseline information about the appropriate peak breeding of the fish, which will be useful for artificial breeding as well for prevention of fishing from natural habitat.     

Reproductive patterns of blacktail comber (Serranus atricauda,Serranidae) from south-west Portugal seamounts

The knowledge of the reproductive strategy is essential for the comprehensive understanding of the population dynamics of any fish species. This study intends to define the spawning season, verify the type of fecundity regulation and estimate relative annual fecundity for Serranus atricauda inhabiting the south-west of Portugal seamounts (Gorringe, Ampère and Lion). Monthly samples, between September 2010 and December 2011, were obtained from commercial vessels. This species is synchronously hermaphroditic, and mature individuals were found all year round, with gonadosomatic index peak from February to September. No clear relation between hepatosomatic index and Fulton’s condition factor and gonadal development was found, and therefore, it is probable that reproductive success depends more on environmental conditions and food availability during the spawning season than on body energy reserves. No gap exists between pre-vitellogenic and vitellogenic oocytes and the oocyte size-frequency distribution during the main spawning season show no dominant cohort progressing through time. The number of standing stock of advanced vitellogenic oocytes showed an increase trend along the spawning season decreasing only at its end and the relative intensity of α-atresia was always low throughout this period with an increase towards the end. All these criteria corroborate the indeterminate fecundity type assigned to S. atricauda in previous studies. Mean relative annual fecundity estimated was 5,655 ± 4,321 oocytes per gram of gutted weight.     

Ovarian activity and plasma sex steroid levels of Distichodus antonii in relation to environmental conditions in the upper basin of the Congo River

Distichodus antonii is an endemic fish species of the Congo River basin in which the stocks of wild populations are threatened by overfishing pressure. Knowledge of its reproductive biology would be useful in consideration of conservation and management options for the species. Therefore, this study investigated changes in ovarian activity and levels of steroid profiles in wild populations in relation to variation in temperature and rainfall. Adult females (n = 101, body weight of 3 183 ± 14.75 g, SE) were captured monthly over one year (2013–2014). Apart from evaluation of oocyte diameters and gonad developmental stages, gonado-, hepato-, lipososomatic indices (GSI, HSI, LSI) and plasma levels of sex steroids (testosterone-T, estradiol-17β-E2) were determined. The results suggested a synchronous development of oocytes with two annual reproductive seasons over the one-year study. Plasma T and E2 levels peaked during spawning periods likely reflecting active oogenesis. The highest values of morphosomatic indices were observed during the longest rainfall period in September, and were associated with high steroidogenic activity evidenced by increased E2 production. In addition, more vitellogenic oocytes (September and October) were observed during the latter season than during the short rainy season (in May).     

Aspects of the reproductive biology of two archer fishes <Emphasis Type="Italic">Toxotes chatareus</Emphasis>, (Hamilton 1822) and <Emphasis Type="Italic">Toxotes jaculatrix</Emphasis> (Pallas 1767)

Various aspects of the reproductive biology of two archer fishes Toxotes chatareus and Toxotes jaculatrix were studied to describe gonad development, spawning season, sex ratio, and fecundity. Spawning season was assessed using monthly changes in gonadosomatic index (GSI) and histological inspection of the gonads. Both species exhibit two modes of oocytes; a mode of small primary growth oocytes and a single mode that increases with size as oocytes sequester vitellogenin and undergo maturation, showing the synchronous oocyte development typical of total spawners. Based on GSI values and advanced stages of oocyte maturity, T. chatareus and T. jaculatrix, females appear to spawn from November to December. The average fecundity of female T. chatareus was 55 000 ± 5538 eggs, and T. jaculatrix was 50 000 ± 3440 eggs; fecundity ranged from 20 000 to 150 000 eggs for both species, with relative fecundities of 600 to 1100 eggs/g body weight, and a mean value of 800 ± 32 for T. chatareus; relative fecundity ranged from 500 to 1100 with a mean value of 700 ± 23 for T. jaculatrix. Sex ratio, defined as the proportion of males to females, was 2.2 and 2.5 in T. chatareus and T. jaculatrix, respectively. The apparent abundance of males in samples could be due to females being positioned lower in the water column and therefore being sampled less frequently. Our results indicate that in both species, spawning occurs between the months of November and December during the monsoon season, which provides the mangrove coastal waters inhabited by these species with an abundance of food resources and additional floodplain nursery habitat for larvae and juveniles.     

Batch fecundity and spawning frequency of invasive Hemiculter leucisculus (Basilewsky, 1855) in Erhai Lake,China

Hemiculter leucisculus are multiple spawners with indeterminate fecundity, although previous fecundity estimates have assumed a determinate spawning pattern. Batch fecundity and spawning frequency of H. leucisculus were studied in Erhai Lake, China, in which the fish, as an exotic species, has become a successful colonizer. Spawning frequency was 16.05 %, as determined from the percent of females with postovulatory follicles 12 to 36 h old during the peak reproductive period (from May 27 to August 8). The average interval between spawning was 6.2 days and there were more than 16 total spawning batches during the peak reproductive period. The average batch fecundity (mean ± SD) was 11,934?±?5,921 hydrated oocytes in 40 females (standard length or SL: 9.1–14.4 cm), while relative batch fecundity was 560?±?137 eggs g^?1 wet weight. The total potential annual fecundity was approximately 190,944 oocytes over the whole spawning season and was much higher than the estimated standing stock (31,585 oocytes) of yolked oocytes (36 females, SL: 9.5–16.2 cm) at the beginning of the spawning season in April 2010. This high annual fecundity is likely to have contributed to successful invasion of Erhai Lake by H. leucisculus.     

Reproductive strategy of the Patagonian catfish Hatcheria macraei

This study describes the reproductive strategy of the stream‐dwelling catfish Hatcheria macraei in the Pichileufu River, Argentina. Gonad maturity phases, classified on the basis of histological analysis, stages of gamete development and the frequency distribution of oocyte size, were correlated with macroscopic features of the gonads. Hatcheria macraei has a cystovarian ovary, asynchronous oocyte development and lobular testes. Five oocyte and four spermatogenic stages were identified and related to macroscopic gonad characteristics, making it possible to divide gonad development into five phases for females and males. Mature oocyte diameter ranged from 922 to 1935 µm. Absolute fecundity in mature females varied from 115 to 480 oocytes. Hatcheria macraei has multiple spawning during a protracted reproductive season that extends from December to April. This, together with its small size, is characteristic of an opportunistic reproductive strategy, commonly found in species that inhabit adverse and unpredictable environments, such as the low‐order rivers of Patagonia.     

The reproductive cycle,size at maturity and fecundity of garfish (<Emphasis Type="Italic">Belone belone</Emphasis>, L. 1761) in the eastern Adriatic Sea

A recent study concerning the reproductive biology of the garfish (Belone belone, L. 1761) has been carried out in the eastern part of the Adriatic Sea along the Croatian coastline. Specimens of the fish (N = 3,393) were collected over a 6-year period (2003–2008). Their length varied between 20.8 and 75.4 cm (mean ± SD = 38.3 ± 7.94). Female garfish were dominant in larger length groups being most apparent during the resting phase of sexual cycle and in the peak of the spawning period, occurring in April and May. The sexual ratio of all specimens was m/f = 0.98. Males were prevalent in March—at the beginning of the highest spawning activities. Fifty percentage of the garfish population sexually matured at 28.5 cm of total length. Males and females reached their sexual maturity at 28.0 and 31.5 cm of total length, respectively. Spawning began in January peaking during March to May. According to their maturity stages, gonad weight and the gonadosomatic index, males began to spawn one month earlier (April) than females (May). The mean batch fecundity of garfish was 1,242.46 ± 843.64 of matured oocytes per ovary. Matured oocyte diameters ranged from 1.223 to 4.283 mm with the mean value of 2.269 ± 0.332 mm.     

Reproduction mode of European Bitterling (Rhodeus amarus,Bloch, 1782) determined through rapid oocyte counts and size determination using digital imaging

This study focuses on assessing the reproduction mode of an important model species for evolutionary and behavioural ecology by using digital image analysis: the European bitterling Rhodeus amarus (Bloch, 1782). Specifications of mode of reproduction were determined using oocyte size distribution, seasonal dynamics in mean oocyte diameter and total number of oocytes in ovary samples gained from April to July 2007. The rapid oocyte count was enabled by using lucia image analysis software, which also provided measurement and colour estimations of oocytes. Bitterling ovaries showed features typical for indeterminate spawners, i.e. a continuous distribution of oocyte size over the reproductive season and recruitment of new pre‐vitelogenic oocytes in the second half of the reproductive season. These results are consistent with the view that the European bitterling is a batch spawning fish with indeterminate fecundity.     

Reproductive guilds (maturation,spawning frequency and fecundity) in the black pomfret,Parastromateus niger (Carangidae) in the Kuwaiti waters of the Arabian Gulf

Oogenesis, oocyte maturation pattern, spawning rhythm, spawning frequency, batch fecundity and oocyte diameter–frequency distribution of the black pomfret, Parastromateus niger (Bloch, 1795) in Kuwaiti waters were investigated from October 2003 to September 2005, using histological and morphological methods. The process of development is divided into four major phases: (i) primary growth phase; (ii) secondary growth phase; (iii) maturation phase; and (iv) spawning phase, followed by the regressed phase. Development of the yolky oocyte is an asynchronous process resulting, by the time of oocyte maturation, in a clear differentiation between a ready batch of oocytes (ready for spawning) and a reserve pool. Consequently, P. niger is capable of spawning multiple times throughout the reproductive season. Spawning frequency estimates, based on final oocyte maturation (FOM) method indicated that the species spawns once every 2.8 days during an 8‐month spawning season lasting from February to September, with a potential annual number of 22.4 spawns. Batch fecundity (BF) (2132–2001 648, mean 406 010 eggs), was significantly positively related to both standard length (SL) (P < 0.05) and ovary‐free body weight (OFBW) (P < 0.05), both parameters being good predictors of BF (r² = 30.8% for SL, from 22 cm onwards, and r² = 29.6% for OFBW, from 129.5 g onwards). No significant differences in monthly BF were found throughout the spawning season. Relative batch fecundity was 336 eggs/g OFBW; thus, estimate for potential annual relative batch fecundity was 7526 eggs g^?1 OFBW. The oocyte diameter–frequency distribution analysis revealed a multimodal distribution (at 100–200, 300–400 and 500–700 μm), confirming the evidence of multiple spawning.     

Reproduction and fecundity of tucunaré, Cichla kelberi (Perciformes: Cichlidae), an exotic species in Três Marias Reservoir, Southeastern Brazil

To evaluate the reproductive cycle and fecundity of tucunaré ( Cichla kelberi Kullander & Ferreira, 2006), 697 specimens were captured in Três Marias Reservoir, São Francisco River, Brazil during 1994–1995 and 2005–2006. Reproductive activity was recorded throughout the sampling periods, with females exhibiting asynchronous oocyte development and multiple spawnings with a peak in September–October. Vitellogenic oocytes of the tucunaré were elliptical in shape with the longest diameter approximately 1230 μm and the shortest 700 μm, yolk globules with ellipsoid inclusions, lipid vesicles, small cortical alveoli and thin zona radiata (9.3 ± 2.0 μm thickness). Follicular cells were prisma-shaped (49.0 ± 16.4 μm) in the vegetative pole, progressively becoming cubic cells in the animal pole toward the micropyle. Histochemical analyses indicated the presence of mucosubstances in the outer zona radiata and follicular cells that could be contributors to egg adhesiveness. Batch fecundity ranged from 4450 to 13 900 oocytes for females 31.5–43.5 cm total length, respectively, and correlated to gonadal weight ( r ² = 0.80) and body weight ( r ² = 0.70). Mean relative fecundity was 10.6 vitellogenic oocytes per gram body weight. As tucunaré is an exotic piscivorous species well-adapted to the Três Marias Reservoir, the present work may be considered a contribution toward future strategies for population control.     

Population structure and reproductive biology of Schilbe intermedius (Teleostei: Schilbeidae) in the Pendjari River,Benin

This study, the first on fish reproduction in the Pendjari River, investigated aspects of the reproductive biology of Schilbe intermedius. A total of 429 females and 239 males were collected from March 2007 to February 2008. Females were larger than males and the sex ratio was 1:1.8 in favour of females. Size at first maturity was estimated to be 14.9 cm and 16.1 cm for males and females, respectively. Absolute fecundity ranged from 1 006 to 83 980 (22 421 ± 16 083) oocytes, and mean relative fecundity was 201 ± 162 oocytes g^?1 of total body mass. Frequency distributions of oocyte diameter suggested synchronous development, with total spawning. Spawning lasted from June to November, coinciding with peaks in rainfall and flooding. Larger females began spawning about two months before smaller ones.     

Goosefish Lophius americanus fecundity and spawning frequency,with implications for population reproductive potential

To improve knowledge of goosefish Lophius americanus' reproductive biology, females were collected during 2009–2012 from the Mid‐Atlantic Bight shelf region of the U.S. east coast. Batch fecundity increased with total length (L_T), from 229 100 to 2 243 300 mature oocytes per female (L_T range: 55·5–112 cm; n = 54). This estimate of fecundity at L_T is lower than one derived from a sample collected during 1982–1985. Examination of whole oocyte diameters in different months indicated that L. americanus is a serial spawner, releasing more than one egg veil per spawning season, as suspected or observed for other Lophius species. Seasonality of spawning was evident from whole oocytes and gonad histology, and from larval fish surveys spanning the U.S. north‐east shelf, and confirmed a protracted (c. 6 months) spawning period. Peak spawning activity progressed northward from spring to autumn. The population‐level implications of these results were explored by estimating population reproductive potential (P_RP), which considered the value of both current and future per capita reproduction using decade‐specific age structure and fecundity at length. P_RP is now more than 50% lower compared with the historical period (1982–1985), a result of the lower proportions of large females and reduced fecundity across all sizes. Mechanisms that could explain this loss of stock productivity are fishing‐induced size–age truncation or regime shifts in egg production caused by changes in energy density of common forage species.     

The reproductive biology of the cyprinid, Thynnichthys thynnoides (Bleeker), in the Chenderoh Reservoir — a small tropical reservoir in Malaysia

The reproductive biology and breeding cycle of a tropical cyprinid, Thynnichthys thynnoides (Bleeker), from Chenderoh Reservoir, Malaysia was studied from June 1991 to November 1992. A total of 329 and 246 mature females and males and 167 immature females were sampled during the study. Three breeding cycles were observed and the cycles coincided with high reservoir water level which resulted in the floodings of the littoral zone. Five and four gonad developmental stages were observed for females and males, respectively. Oocyte diameter distribution study indicated the species was a total spawner although clutches of ripe oocytes might be released over an extended time period. Fecundity was related to body weight and both absolute and relative fecundity increased with body size. Absolute fecundity ranged from 26962 ± 1484 to 173520 ± 127420 eggs fish^–1, whereas relative fecundity ranged from 121 ± 53 to 451 ± 259 eggs g^–1 body weight, respectively.     

Fecundity of Atlantic sturgeon (Acipenser oxyrinchus Mitchill, 1815) captured by the commercial fishery in the Saint John River,New Brunswick,Canada

Knowledge of fecundity in fishes is important for understanding life history, modeling population dynamics, developing fisheries management and determining conservation status. Sturgeon species are known for their high fecundity but to date only two populations of Atlantic sturgeon (Acipenser oxyrinchus Mitchill, 1815) have been examined for this aspect of their biology. The species is protected in most regions of eastern North America but the Saint John River, New Brunswick supports one of the two remaining commercial fisheries in Canada. Sixty females selected by this fishery were sampled for total length, weight, age, gonad weight and egg number. Absolute fecundity ranged from 153,630 to 1,306,626 eggs, with a mean fecundity of 582,832 ± 261,806 eggs. Absolute fecundity exhibited a significant positive relationship to increasing body weight but not to total length or age. Relative fecundity ranged from 129 to 216 eggs/g gonad weight and although it declined with both increasing body size and age the relationships were not significant. The Gonadosomatic Index (GSI) ranged from 1.3% to 27.0% with a mean of 7.8% ± 4.94 SD. Relative fecundity found in this study was higher and mean GSI lower than reported for other Atlantic sturgeon populations and other sturgeon species. Differences were probably due to location of the fishery downstream from spawning sites and selection of pre-spawning females by the commercial fishery.     

湖南沅水下游?繁殖期内繁殖力和卵径的变化研究

为分析鱼类繁殖期内繁殖力和卵径变化趋势, 研究于4—10月在沅水下游逐月采集180尾?(Hemiculter leucisculus), 分析81尾雌性成熟个体的繁殖力。研究结果表明: ?的性体指数在5、6月最高, 其次在7、8和9月, 在4和10月最低。绝对繁殖力平均值为(30116±19390)粒, 以10000—30000粒为主, 相对繁殖力的平均值为(650±324)粒/g, 以400—800粒/g为主。绝对繁殖力与体长、空壳重呈幂函数关系(P<0.05)。绝对繁殖力和相对繁殖力在5和6月最大, 7、8和9月次之, 在4和10月最小。不同月份成熟卵子的卵径无显著差异, 补充卵子的卵径在5和6月最大, 暗示5和6月分批繁殖次数较多。不同繁殖时期的分批繁殖力、繁殖次数不一样, 对评估种群的繁殖潜能具有重要的指导意义。比较不同水系繁殖力发现, 湖泊种群的个体繁殖力普遍大于河流种群, 沅水种群的个体繁殖力跟湖泊种群的相似, 可能与其具有类似湖泊的缓流水或静水生境有关。研究揭示了?的基本繁殖特征, 为渔业资源管理提供了基础数据资料。