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1.
The reproductive biology of female bigeye tuna Thunnus obesus was assessed by examining 888 fish (ranging from 84·9 to 174·4 cm fork length, LF) caught by Taiwanese offshore longliners in the western Pacific Ocean from November 1997 to November 1998 and November to December 1999 and 258 gonad samples from these fish. The overall sex ratio of the catch during the sampling differed significantly from 0·5, but males were predominant in sizes >140 cm LF. Reproductive activity (assessed by histology), a gonado‐somatic index, and the size‐frequency distributions of whole oocytes indicated that spawning occurred throughout the year and the major spawning season appeared to be from February to September. The estimated sizes at 50% maturity (LF50) of females was 102·85 cm (95% c.i .: 90·79–110·21 cm) and the smallest mature female was 99·7 cm LF. They are multiple spawners and oocytes develop asynchronously. The proportion of mature (0·63) and reproductively active (0·70) females with ovaries containing postovulatory follicles indicated that they spawn almost daily. Batch fecundity for 15 females with the most advanced oocytes (>730 µm) ranged from 0·84 to 8·56 million eggs (mean ± s.d . = 3·06 ± 2·09). The relationships between batch fecundity (FB, in millions of eggs) and LF (cm) and round mass (MR, kg) were (r2 = 0·84) and (r2 = 0·80), respectively. The parameters estimated in this study are key information for stock assessments of T. obesus in the western Pacific Ocean and will contribute to the conservation and sustainable yield of this species. 相似文献
2.
This study examined the spawning season, spawning frequency and batch fecundity of yellow sea bream Dentex hypselosomus in the East China Sea to reassess the previously reported reproductive characteristics of the species. Time-course sampling showed that this species had a diurnal ovarian maturation rhythm. Late tertiary yolk-stage oocytes appeared 2 days before spawning, starting the process of germinal vesicle movement and breakdown. On the day of spawning, ovulation and subsequent spawning occurred in the early morning (0400–0800 hours). Postovulatory follicles disappeared from the ovaries within c. 24 h of ovulation. Seasonal changes in the ovarian conditions indicated that this species spawned more or less throughout the year, with the peak ranging from spring to autumn. The compositions of the developing oocytes and degenerating postovulatory follicles in the ovaries suggested that most females spawned repeatedly over 2 to 3 consecutive days during the peak of the spawning season. Somatic body condition did not have a significant effect on batch fecundity, but there was a significant relationship between batch fecundity and fork length according to spawning status. Females spawning on consecutive days were more fecund than those spawning every other day. The findings show that this species has much greater reproductive potential than previously estimated. 相似文献
3.
Quang Minh Dinh Lam Thanh Tran Nhu Chon Ngo Tram Bich Pham Tien Thi Kieu Nguyen 《Acta zoologica》2020,101(2):206-217
This study provided new knowledge on reproductive traits of the unique mudskipper Periophthalmodon septemradiatus that is also a potential aquarium pet. Fish specimens were obtained by using fishing rods at the muddy flat in tributaries of the Hau River from August 2017 to July 2018. Data analysis of a collection of 1,504 individuals (930 males and 674 females) showed that the sex ratio of this species was significantly different from the ratio 1:1. As mature gonads were found monthly during the study period, it is suggested that P. septemradiatus is an iteroparous species releasing eggs for a year-round cycle. The fish length at first mature (Lm) showed an increase from estuary to upstream areas. Male P. septemradiatus had higher Lm values than that of females. Likely, the batch fecundity increased from estuary region (5,916 ± 312 SEM eggs) towards upstream area (11,451 ± 953 SEM eggs). The fish total length and weight values had strong positive relationships with batch fecundity, as shown by high determination values (r2), suggesting that batch fecundity increased with fish size. This study provided more information on reproductive biology of P. septemradiatus, which can be utilized for fish population conservation and artificial reproductive study. 相似文献
4.
Reproductive variables in albacore Thunnus alalunga were evaluated by gonad histology in samples of 132 males (58–118 cm fork length, LF) and 112 females (59–101 cm LF) that were collected from the western North Pacific Ocean from 2001 to 2006. In the sex ratio examination, males greatly outnumbered females in large adult fish (LF > 100 cm). Thunnus alalunga exhibited a protracted spawning period from March to September in the waters off eastern Taiwan and the Philippines, and the peak spawning activity occurred in March and April. Minimum sizes associated with the classification of mature fish were 78 and 83 cm LF for males and females, respectively. In addition, the largest LF of immature fish were 93 cm for males and 94 cm for females. The spawning frequency estimate in April was 1·7 days. Batch‐fecundity estimates of 21 females (89–99 cm LF) ranged between 0·17 and 1·66 million eggs (mean ±s.d . = 0·94 ± 0·43). The relative fecundity estimates of the 21 females ranged between 9·2 and 92·4 oocytes g?1 body mass (mean ±s.d . = 50·5 ± 22·8). The results presented in this study provide increased information regarding this species' reproductive‐related characteristics than are currently available in stock status determinations. 相似文献
5.
The strategy of multiple spawning is examined in several commercially important species—in particular turbot, Scophthalmus maximus (L.); halibut, Hippoglossus hippoglossus (L.); cod, Gadus morhua L.; and northern anchovy, Engraulis mordax Girard. Aspects of special relevance to fishery science and commercial and experimental cultivation are discussed. These include changes in batch fecundity and egg size as the spawning season progresses; the timing and methodology of fecundity estimations; ovulatory/spawning rhythms; the effect of temperature on the ageing rate of retained ovulated oocytes and the interovulatory period; ovulation prediction in hand-stripped broodstocks to facilitate the collection of good quality, freshly ovulated eggs, and the effect of maternal stress on the ovulatory/spawning rhythm. The implications of these phenomena are discussed in terms of recommended practices for the culturist, experimentalist and fisheries scientist. 相似文献
6.
Length and mass data for 1260 (536 females, 683 males, 41 sex unknown) striped marlin Kajikia audax were collected at the fish markets of Tungkang, Singkang and Nanfangao from July 2004 to September 2010. Of these samples, 534 gonads (236 females and 298 males) ranging from 95 to 206 cm in eye‐to‐fork length (L EF ) and 8 to 88 kg in round mass (M R), were collected. Chi‐square tests indicated sex ratios were homogeneous among months in 2004 and 2006–2008, but not in 2005, 2009 and 2010; and there were significant differences in sex ratio by size. The overall sex ratio (R S ) differed significantly from the expected 0·5. Kajikia audax are sexually dimorphic and the proportions of females increased with size between 140 and 210 cm L EF . Reproductive activity was assessed using a gonado‐somatic index (I G ), external appearance of the gonads and histological examination and results indicated that the spawning season occurred from April to August with a peak in June to July. Based on histological observations and the distribution of oocyte diameters, K. audax are multiple spawners and their oocytes develop asynchronously. The estimated length‐at‐50% maturity (L EF50 ) was c . 181 cm (c . 4·8 years of age) for females. The proportion of reproductively active females in the spawning season with ovaries containing postovulatory follicles (0·27) indicated that they spawned every 3·7 days on average. The hydrated oocyte method estimated mean ± S.D. batch fecundity (F B ) to be 4·4 ± 2·02 million eggs; average relative fecundity was 53·6 ± 13·9 oocytes g?1 M R; and the average annual fecundity was 181·3 ± 48·3 million eggs. The parameters estimated in this study are key information for stock assessments of K. audax in the north‐western and central Pacific and will contribute to the conservation, management and sustainable yield of this species. 相似文献
7.
Q. M. Dinh 《Zeitschrift fur angewandte Ichthyologie》2018,34(1):103-110
This study provides knowledge on reproductive traits of Trypauchen vagina, a target fish for catching, based on data analysis of 701 individuals collected in the Mekong Delta from January to December 2015. The species is a multiple spawner depositing eggs in early wet season (June–August) since gonadosomatic index reaches a high point during this period, supported by the appearance of ripe and spent gonads at that time. Male and female fish matures firstly at 16.59 and 16.81 cm in total length respectively. The species displays high batch fecundity (4,000–12,750 eggs/female). Knowledge of length at first maturity and spawning season is essential for local authorities to set the suitable fish length and time for fishing. The results provide fundamental information on the reproductive biology and contributed to knowledge for fish population sustainable management. 相似文献
8.
We report on the reproductive biology of southwestern Atlantic wreckfish. Females mature first at 77.9cm total length (TL) (10.4 years) and all are mature by 90cm TL (15.2 years). Males mature first at 74.9cm (9 years) and all are mature by 80cm TL (10.9 years). The wreckfish is a gonochoristic multiple spawner and the gonadal cycle is synchronized at the population level. Spawning occurs from late July to early October along the continental slope (<300m). Ovarian fecundity varies from 3 to 11.9 million (135–311 oocytes×g–1) and increases exponentially with length. Spawning at western boundary current systems, maintained by homing of adults, is a basic requirement for self-sustaining populations of this species. 相似文献
9.
Renjithkumar Chelapurath Radhakrishnan Roshni Kuttanelloor Madusoodana Kurup Balakrishna 《Zeitschrift fur angewandte Ichthyologie》2020,36(5):604-612
The study provides new information on the reproductive biology of Hypselobarbus thomassi (Day, 1874) an endemic cyprinid fish in the Western Ghats–a biodiversity hotspot of India. A total of 384 specimens (males = 244 and females = 140) were collected monthly from April 2009 to March 2011 from Kallada River of Southern part of Western Ghats, India. Monthly sex ratio indicated that males predominated in the fishery, and an overall sex ratio was significantly different from the expected value of 1:1 (male:female = 1:0.57, x2 = 28.17, p < .01). Based on the monthly analysis of gonadosomatic index (GSI) and the proportion of mature individuals, the spawning season of H. thomassi occurred between May to October with a peak in June to August. The length at first maturity (L50) recorded was 290 mm TL in males and 330 mm TL in females. The absolute fecundity ranged between 305 (234 mm TL) to 1,089 (414 mm TL) and relative fecundity oscillated between 77.3–220.69 oocytes/g of fish. The fecundity established a linear relationship with total length, body weight and ovary weight. The findings of this study would be very effective to impose sustainable conservation plan for this threatened species in Kallada River and other Western Ghats river systems. 相似文献
10.
Lisa A. Privitera 《Environmental Biology of Fishes》2002,65(3):289-310
A population of the Hawaiian coral-reef goby, Asterropteryx semipunctata, was sampled over a 12-month period to determine basic demographics and reproductive parameters. The sexes did not differ in median length or weight, although the largest males were considerably longer and heavier than the largest females. Overall adult sex ratio was 1:1; monthly sex ratios did not differ from unity except in June, when there was a significant female bias. Minimum age at maturity (17.5–19mm SL) was estimated to be 4.5–5 months after hatching. Nearly all fish over 22mm SL were mature. Mature females were found in all months of the year, and females that showed evidence of recent or imminent spawning were collected in every month except December. Gonadal analyses indicated a peak in breeding during the summer (May–July) and minimal spawning during the winter (January–February). Between 20% and 30% of females showed evidence of having spawned within the 24-h period prior to collection; therefore, it was estimated that females spawned, on average, at least once every five days and perhaps as frequently as every three days. Mean batch fecundity was 708 eggs (± 418), and was not well predicted by standard length, body weight, or somatic condition. Relative batch fecundity (mean = 1.44 oocytes mg–1 somatic wet weight) varied seasonally, with higher values in spring and summer (April–July) than in fall and winter (September–January). Reproductive parameters are compared and contrasted with those of other gobiid fishes to elucidate general differences between temperate and tropical species. 相似文献
11.
Macrhybopsis reproduction and propagule traits were studied in the laboratory using two temperature regimes and three hormone treatments to determine which methods produced the most spawns. Only sicklefin chub Macrhybopsis meeki spawned successfully although sturgeon chub Macrhybopsis gelida released unfertilized eggs. All temperature and hormone treatments produced M. meeki spawns, but two treatments had similar success rates at 44 and 43%, consisting of a constant daily temperature with no hormone added, or daily temperature fluctuations with hormone added to the water. Spawns consisted of multiple successful demersal circular swimming spawning embraces interspersed with circular swims without embraces. The most spawns observed for one female was four and on average, 327 eggs were collected after each spawn. The water‐hardened eggs were semi‐buoyant and non‐adhesive, the first confirmation of this type of reproductive guild in the Missouri River Macrhybopsis sp. From spawn, larvae swam vertically until 123 accumulated degree days (° D) and 167° D for consumption of first food. Using average water speed and laboratory development time, the predicted drift distance for eggs and larvae could be 468–592 km in the lower Missouri River. Results from this study determined the reproductive biology and early life history of Macrhybopsis spp. and provided insight into their population dynamics in the Missouri River. 相似文献
12.
The testicular and ovarian maturation cycle of thedory snapper, Lutjanus fulviflamma(Forsskål) (Osteichthyes:Lutjanidae), acommercially valuable species in the western IndianOcean, is described macroscopically. The ovary wasalso studied microscopically. L. fulviflammahas one prolonged spawning season which begins fromNovember/December, lasting till April/May. Discontinuous spawning is established by (i) temporalvariation in the relative weight of testis andovaries, (ii) a seasonal occurrence of various maturitystages and, (iii) a seasonal occurrence of developingfish in the samples. Using volumetric andhistological techniques, the fecundity of this specieswas determined at 51,000 to 460,000 (mean: 167,000)oocytes in fish of between 17 to 30 cm total length,respectively. Oocyte recrudescence in the ovary isasyncronous, but the number and size of batches ofeggs released in a single spawning season are yet tobe determined. 相似文献
13.
Life cycle and reproductive biology of the marbled goby Pomatoschistus marmoratus was studied in the Venetian Lagoon. Lifespan was determined by reading otoliths. The maximum age recorded was 17 months juveniles occurred in samples from July to November. Nests were found in two different periods: from the middle of April to the middle of July and from the middle of August to the end of September. While individuals in a wide range of body size (35–62mm total length) mated during the first spawning peak during the second one only small individuals (28–32mm total length) developed during the first peak were in reproductive activity. Histological analyses showed that most of the juveniles developed during the first spawning peak delayed sexual maturation to the following year. Ripe females appeared to be multiple spawner showing an asynchronous ovary with oocytes at different stages of development. From nesting male body sizes gonadosomatic indices and histological analyses no indication of the presence of alternative male mating tactics emerged. 相似文献
14.
Maturation, minimum length at first maturity, spawning season, spawning periodicity, sex-ratio and absolute fecundity of Mystus vittatus, a common bagrid catfish, have been investigated. The observations show that spawning takes place during September and October. Each individual spawns only once in the season as evidenced by the study of the intraovarian ova. Females dominate the catches, and absolute fecundity (F) can be expressed by% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaOabaeqabaGaciiBai% aac+gacaGGNbGaaeiiaiaabAeacaqGGaGaaeypaiaabccacaqGTaGa% ae4maiaab6cacaqGYaGaaeyoaiaabkdacaqGGaGaae4kaiaabccaca% qG0aGaaeOlaiaabgdacaqG3aGaaeymaiaabgdacaqGGaGaaeiBaiaa% b+gacaqGNbGaaeiiaiaabYeaaeaacaqGHbGaaeOBaiaabsgacaqGGa% GaaeOraiaabccacaqG9aGaaeiiaiaab2cacaqGXaGaaeOlaiaabwda% caqG0aGaaeinaiaabwdacaqGGaGaae4kaiaabccacaqGWaGaaeOlai% aabMdacaqG0aGaae4naiaabkdacaqGGaGaae4vaaaaaa!5FCC!\[\begin{gathered} \log {\text{ F = - 3}}{\text{.292 + 4}}{\text{.1711 log L}} \hfill \\ {\text{and F = - 1}}{\text{.5445 + 0}}{\text{.9472 W}} \hfill \\ \end{gathered} \] 相似文献
15.
The reproductive biology of Liza argentea and Myxus elongatus occurring in two estuaries (Lake Macquarie and St Georges Basin) was found to differ. Gonado‐somatic index values and macroscopic staging of gonads identified the peak spawning period of L. argentea occurred between March and November in Lake Macquarie and January and April in St Georges Basin. In contrast, peak spawning of M. elongatus was concentrated between January and March in both estuaries. Spawning of L. argentea probably occurred in the lower reaches of estuaries as well as in nearshore coastal waters, whereas evidence indicated M. elongatus spawned only in ocean waters. The mean fork length at maturity (LF50) was greater for females than males in both species, and it also occurred at a larger mean LF in M. elongatus (males = 230 mm and females = 255 mm) than L. argentea (males = 180 mm and females = 207 mm). Estimates of total potential fecundity were also greater for M. elongatus (425 484–1 157 029) compared to L. argentea (159 933–548 954). Both species had determinate fecundity and displayed a group synchronous pattern of oocyte development, with two distinct size classes of oocytes present in mature ovaries. Liza argentea probably release the larger class of oocytes in one spawning event, but this could not be established for M. elongatus. 相似文献
16.
Thomas?P.?Bassista Kyle?J.?Hartman "author-information "> "author-information__contact u-icon-before "> "mailto:hartman@wvu.edu " title= "hartman@wvu.edu " itemprop= "email " data-track= "click " data-track-action= "Email author " data-track-label= " ">Email author 《Environmental Biology of Fishes》2005,73(1):49-59
Synopsis Bay anchovy, Anchoa mitchilli, is an ecologically important species in coastal systems, acting as predators on zooplankton while serving as prey for many birds and economically important finfish species. Despite the importance of bay anchovy, limited information exists concerning reproductive biology and egg mortality from the northern parts of its range. Spawner demographics suggested Hudson River fish were older and larger than reported elsewhere. Egg mortality rates were higher in the Hudson River than reported in more southerly systems. Differences in the reproductive biology of bay anchovy suggest either anthropogenic factors or latitudinal differences between populations exist and therefore should warrant further investigations on this species in the northern portions of its range 相似文献
17.
A. García Vásquez J.‐C. Alonso F. Carvajal J. Moreau J. Nuñez J.‐F. Renno S. Tello V. Montreuil F. Duponchelle 《Journal of fish biology》2009,75(10):2527-2551
The main life‐history traits of the dorado Brachyplatystoma rousseauxii, a large Amazonian catfish undertaking the largest migration known for a freshwater fish species (from the nursery area in the estuary of the Amazon to the breeding zones in the head waters of the western Amazon basin close to the Andes), were determined from a 5 year sampling of >15 000 specimens in the Peruvian Amazon. The breeding season occurred during the falling and low‐water periods, which is hypothesized to be an adaptation to maximize the chances of young stages to reach the estuary. The size at first sexual maturity was slightly larger for females than males, c. 91 and 83 cm standard length (LS), respectively. Both males and females reproduce for the first time at >3 years old. The fecundity per spawning event ranged from 481 734 to 1 045 284 oocytes for females weighing 25 and 34 kg, respectively. Seasonal variations of body condition were similar among sexes, but differed between immature specimens that had a higher condition during the low‐water period and lower condition during rising waters, and mature individuals that showed the opposite pattern. The growth characteristics were estimated by LS frequency analysis. For females, the best fitting models gave a mean birth date in August, during the height of the breeding cycle, with the following von Bertalanffy growth function parameters: LS∞ = 153·3, K = 0·29 and t0 =– 0·37 years. For males, the best fitting model gave a mean birth date in July, also during the height of the breeding period, with LS∞ = 142, K = 0·30 and t0 =– 0·36 years. At a given age, females were systematically larger than males and the size difference increased with age. The largest females sampled (148 cm LS) was 11 years old and the largest male (134 cm LS) was 9 years old. The mortality estimates were higher for males total (Z) = 1·34, natural (M) = 0·52 and fishing (F) = 0·82 than for females (Z = 0·98, M = 0·50, F = 0·48). The life‐history patterns of B. rousseauxii are discussed in light of the available knowledge about this species and the understanding of its complex life cycle. 相似文献
18.
Histological examination of ovaries from European hake Merluccius merluccius from the Bay of Biscay sampled on a monthly basis from December 1996 to October 1997 demonstrated that European hake exhibit indeterminate fecundity. Oocyte development is asynchronous with a continuous oocyte size-frequency distribution in prespawning, spawning and postspawning females, and a gradual decrease in the mean diameter of advanced yolked oocytes as spawning proceeds. Spawning European hake were observed throughout the 11 month study period. The spawning fraction ranged from 0·085 to 0·207, which is equivalent to a batch interval of 5–12 days. The spawning fraction and proportion of spawning females were highest from January to March. Seasonal variation of atresia was inversely related to spawning fraction. Extensive atresia in individual fish was observed in September and October, when the spawning fraction was low. 相似文献
19.