Seasonal Changes in the Milt Quality of Waigieu Seaperch,Psammoperca waigiensis: Implications for Artificial Propagation          下载免费PDF全文

Minh Hoang Le  Hung Quoc Pham 《Journal of the World Aquaculture Society》2018,49(5):857-866

Milt quality of Waigieu seaperch was sampled at the beginning, the middle, and the end of the spawning season to assess if the sampling season has an effect on milt quality parameters. The milt volume and total sperm production were higher at the middle of the spawning season while the sperm concentration in milt was significantly higher at the beginning and the end of the spawning season. Sperm morphology and the major parameters of seminal plasma (pH, total protein, Mg²⁺, or Ca²⁺ concentrations) did not differ throughout the spawning season. The concentrations of Na⁺ and the osmolality increased throughout the spawning season. The percentage of motile cells did not differ during the spawning season while the duration of sperm motility (swimming duration) and velocity (swimming speed) were significantly different during the spawning season. The fertilization rate (75.7 ± 6.8%) and hatching rate (56.5 ± 3.1%) at the middle of the spawning season were higher than at the beginning and end periods. Results indicated that milt quality parameters and fertility success in the middle of the spawning season were higher compared to earlier and later sampling dates. Thus, we recommend collecting milt during this time for maximal fertilization and hatching success.  相似文献   

Spawning time and place of the Japanese eel Anguilla japonica in the North Equatorial Current of the western North Pacific Ocean     

Satoshi Ishikawa  Kunihiro Suzuki  Tadashi Inagaki  Shun Watanabe  Yobuo Kimura  Akihiro Okamura  Tsuguo Otake  Noritaka Mochioka  Yuzuru Suzuki  Hiroshi Hasumoto  Machiko Oya  Michael J Miller  Tae Won Lee  Hans Fricke  Katsumi Tsukamoto 《Fisheries Science》2001,67(6):1097-1103

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Reproductive biology of the female Japanese mantis shrimp Oratosquilla oratoria (Stomatopoda) in relation to changes in the seasonal pattern of larval occurrence in Tokyo Bay, Japan     

Keita  KODAMA  Takamichi  SHIMIZU  Takashi  YAMAKAWA  Ichiro  AOKI 《Fisheries Science》2004,70(5):734-745

ABSTRACT:   The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July.  相似文献   

Distribution,characteristics and condition of Arctic charr (Salvelinus alpinus) spawning grounds in a differentially eutrophicated twin‐basin lake          下载免费PDF全文

Helen Miller  Ian J. Winfield  Janice M. Fletcher  J. Ben James  Joey van Rijn  Jonathan M. Bull  Carol J. Cotterill 《Ecology of Freshwater Fish》2015,24(1):32-43

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Incubation success and habitat selection of shore‐spawning kokanee Oncorhynchus nerka: effects of water‐level regulation and habitat characteristics          下载免费PDF全文

Steven L. Whitlock  Michael C. Quist  Andrew M. Dux 《Ecology of Freshwater Fish》2015,24(3):412-423

Changes to water‐level regimes have been known to restructure fish assemblages and interfere with the population dynamics of both littoral and pelagic species. The effect of altered water‐level regimes on shore‐spawning kokanee Oncorhynchus nerka incubation success was evaluated using a comprehensive in situ study in Lake Pend Oreille, ID, USA. Survival was not related to substrate size composition or depth, indicating that shore‐spawning kokanee do not currently receive a substrate‐mediated survival benefit from higher winter water levels. Substrate composition also did not differ among isobaths in the nearshore area. On average, the odds of an egg surviving to the preemergent stage were more than three times greater for sites in downwelling areas than those lacking downwelling. This study revealed that shoreline spawning habitat is not as limited as previously thought. Downwelling areas appear to contribute substantially to shore‐spawning kokanee recruitment. This research illustrates the value of rigorous in situ studies both for testing potential mechanisms underlying population trends and providing insight into spawning habitat selection.  相似文献   

Littoral spawning habitats of three southern Arctic charr (Salvelinus alpinus L.) populations     

Jonathan J. Low  Fran Igoe  John Davenport  Simon S. C. Harrison 《Ecology of Freshwater Fish》2011,20(4):537-547

Abstract Arctic charr populations in southern latitudes are nonmigratory, with all life‐stages limited to freshwater lakes and in‐ or out‐flowing tributaries. Although many of these populations are reported to also spawn in lake littorals, little is known about the physical characteristics of putative spawning grounds. A total of 23 discrete spawning sites within three Irish lakes were located by fyke netting of spawning adults and snorkelling in littoral habitats. Spawning sites were found to be long, narrow strips running parallel to the shore at a maximum depth of 124 cm. Spawning sites were limited to areas of coarse mineral substrate with an adequate (c. 8 cm) depth of clean interstitial spaces. In individual lakes, combined areas of spawning sites made up 0.4–0.7% of available littoral. Egg densities varied considerably between sites (33–900·eggs m^?2) and were significantly correlated with gradient and width of spawning sites. No evidence of redd digging was found. The shallow, localised and restricted nature of spawning grounds makes such populations vulnerable to anthropogenically induced postoviposition changes in surface water level, eutrophication processes such as increased lake sedimentation and elevated nutrient status.  相似文献   

Reproductive biology of common silver biddy Gerres oyena in Okinawa Island of southern Japan     

Khaled Kanak  Katsunori Tachihara 《Fisheries Science》2008,74(2):265-275

ABSTRACT:   Common silver biddy Gerres oyena were collected monthly between November 2002 and November 2005 in Okinawa Island of southern Japan. The seasonal reproductive cycle of this species was investigated using the gonadosomatic index (GSI) and through histological observation of gonads. Temporal variation in the GSI reflected gonadal development from histological observations; ovary development occurred from March to September and testes development occurred between March and August. Maximal development was observed in April and May in both sexes. While mean values for hepatosomatic and lipidosomatic indices decreased markedly in females relative to males during gonadal development, mean condition factors decreased with gonadal recrudescence in both sexes. The minimum standard length (SL) at sexual maturity was 89.7 mm for females and 81.4 mm for males and the size at which 50% of individuals were sexually mature was 104 and 92 mm SL in females and males, respectively. The power relationships of batch fecundity (BF) versus standard length (SL, mm) and body weight (BW, g) of females can be expressed as BF  = 46.7 × e^{1.64 SL} and BF  = 19 697 × e^{0.49 BW} , respectively.  相似文献   

Effect of low temperature on mating behavior of squid Loligo bleekeri     

Yoko Iwata  Kingo Ito  Yasunori Sakurai 《Fisheries Science》2008,74(6):1345-1347

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Movement patterns of armado, Pterodoras granulosus, in the Paraná River Basin     

M. C. Makrakis  L. E. Miranda  S. Makrakis  D. R. Fernandez  J. O. Garcia  J. H. P. Dias 《Ecology of Freshwater Fish》2007,16(3):410-416

Abstract –  We studied the migratory behaviour of armado, Pterodoras granulosus , in the Paraná River Basin of Brazil, Paraguay and Argentina, during 1997–2005. This species invaded the Upper Paraná River after upstream dispersal was facilitated when Itaipu Reservoir inundated a natural barrier. Fish were tagged ( N  = 8051) in the mainstems of the Yacyreta and Itaipu reservoirs, bays of major tributaries, the Paraná River floodplain above Itaipu Reservoir, and below dams. In all, 420 fish were recaptured of which 61% moved away from the release area. Fish moved a maximum of 215 km (mean 42), and at a maximum rate of 9.4 km·day⁻¹ (mean 0.6). Of the 256 armados that moved away from the release site, 145 moved upstream towards unimpounded stretches of the Paraná River and 111 moved downstream into the reservoir and bays of its tributaries (maximum 150 km). Based on the observed migratory movements, we suspect that most of the reproductive output originates in tributaries to the reservoirs. The ability of this species to expand its range presents a conundrum by pitting fishery management interests against conservation needs. Maintenance of the important armado fisheries depends on the ability of the species to migrate freely to use spawning and nursery areas in reservoir tributaries and floodplains. However, its ability to migrate long distances can allow this non-native species the opportunity to invade most of the Upper Paraná River.  相似文献   

Reproduction of chub, Leuciscus cephalus L., under controlled conditions     

S&#;awomir Krejszeff  Dariusz Kucharczyk  Krzysztof Kupren  Katarzyna Targo&#;ska  rzej Mamcarz  Roman Kujawa  Zbigniew Kaczkowski  & Sebastian Ratajski 《Aquaculture Research》2008,39(9):907-912

Research into artificial reproduction of chub was studied during three subsequent reproductive seasons. Chub reproduction was conducted in two different variations. In the first experiment different hormonal agents were given to fish, such as CPE, hCG, or an analogue of GnRH with dopamine antagonist (ovopel). In the second one, the optimum moment of applying of artificial reproduction was sought and the fish were only obtained an analogue of GnRH in different periods. The results obtained in two first seasons indicated that ovopel is the most effective agent for the artificial reproduction of chub. Consequently, it was decided that the fish would obtain only this agent in the final year of research. In last year (experiment II), chub spawners were taken to the hatchery under controlled conditions every few weeks from February to the beginning of June. Periodically, the maturity of oocytes was checked. As soon as the oocytes had achieved stage 2–3 of maturity, fish were obtained ovopel. It was noted that there was no problem with collecting semen. Obtaining oocytes was much more difficult. Most frequently, they were not obtained at all or obtained in very small amounts. It was also observed that the administration of hormones caused a very quick maturation of gonads and their over-maturation.  相似文献