scholarly journals On the Spawning Season and Spawning Ground of the Japanese gizzard, Konosirus punctatus, in Lake Hamana.

1974 ◽  
Vol 40 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Katsumi MATSUSHITA ◽  
Yukio NOSE
Keyword(s):  
Spawning Season ◽  
Spawning Ground ◽  
Konosirus Punctatus ◽  
Lake Hamana

scholarly journals A study of the life history of Brazilian sardine, Sardinella brasiliensis: II. spawning in 1970 and 1971

1975 ◽  
Vol 24 (0) ◽  
pp. 01-16 ◽  
Author(s):  
Yasunobu Matsuura
Keyword(s):  
Life History ◽  
Southern Hemisphere ◽  
Incubation Time ◽  
Average Diameter ◽  
Considerable Change ◽  
Spawning Season ◽  
Warm Water ◽  
Spawning Ground ◽  
History Of

Distribution and abundance of eggs of Sardinella brasiliensis (=S. aurita), are presented for the years 1970 and 1971 and compared with that of the previous year (1969). The spawning size of three spawning seasons was calculated using Tanaka's method. Incubation time of sardine eggs was estimated using the method of Ahlstrom. During three spawning seasons a considerable change in the relative spawning size was observed. The spawning season (during spring and summer in the southern hemisphere) of 1970-71 was poor when compared with those of 1969-70 and 1971-72. A slight change in the average diameter of eggs in different spawning seasons was also observed. The relation between oceanographie conditions and spawning size was analysed. It is suggested that the warm water covering the spawning ground during the 1970-71 spawning season may have caused an unsuccessful spawning in this year.

scholarly journals Home range and elevated egg densities within an inshore spawning ground of coastal cod

2007 ◽  
Vol 64 (5) ◽  
pp. 920-928 ◽  
Author(s):  
Sigurd Heiberg Espeland ◽  
Ailin Fernløf Gundersen ◽  
Esben Moland Olsen ◽  
Halvor Knutsen ◽  
Jakob Gjøsæter ◽  
...  
Keyword(s):  
Home Range ◽  
Site Fidelity ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Generalized Additive Models ◽  
Spatial Dynamics ◽  
Additive Models ◽  
Spawning Season ◽  
Spawning Ground ◽  
Spawning Site

Abstract Espeland, S. H., Gundersen, A. F., Olsen, E. M., Knutsen, H., Gjøsæter, J., and Stenseth, N. C. 2007. Home range and elevated egg densities within an inshore spawning ground of coastal cod. – ICES Journal of Marine Science, 64: 920–928. Atlantic cod (Gadus morhua) along the Norwegian Skagerrak coast are structured into genetically distinct local populations. Mechanisms contributing to this genetic structure may include spawning site fidelity of adult cod as well as retention of pelagic early life stages close to the spawning grounds. Spawning in sheltered inshore localities is likely to favour retention of eggs and larvae, the opposite situation to offshore spawning. A combined study was made of area utilization by adult cod and the distribution of cod eggs within an inshore locality of the Norwegian Skagerrak coast. The behaviour of adult cod was studied using acoustic telemetry and kernel modelling, and eggs were sampled throughout the spawning season. Generalized additive models were applied to test hypotheses about the spatial dynamics of the eggs, and the best model described a central spawning area that retained its integrity through time. Adult cod were confined to small parts of the study area and remained there throughout the spawning season. The average home range of the adult cod was 27 ha. Overall, the study demonstrated two mechanisms by which coastal (i.e. inshore) cod maintain their population structure: spawning site fidelity and the spatial dynamics of their eggs.

Multiyear homing of Atlantic cod to a spawning ground

2001 ◽  
Vol 58 (12) ◽  
pp. 2325-2329 ◽  
Author(s):  
D Robichaud ◽  
G A Rose
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spawning Season ◽  
Spawning Ground ◽  
Long Distance ◽  
Tag Loss ◽  
Sea Bed ◽  
Placentia Bay

Long-term sonar transmitting tags were implanted in 27 female and 21 male cod (Gadus morhua) at the Bar Haven spawning ground in Placentia Bay, Newfoundland, in April 1998. Two thirds of tagged fish were relocated. All relocations during the 1999 and 2000 spawning seasons were within 10 km of the tagging site, the majority being within a few hundred metres. No tagged fish were relocated at other spawning grounds or elsewhere in the bay during the spawning season. Outside the spawning season, several tagged fish were relocated in other parts of the bay at ranges of a few kilometres to 110 km from the tagging site, as were 13 of 15 fishery returns (2 returns from several hundred kilometres outside the bay). Homing rates in 1999 and 2000 were 39% and 53%, respectively, after adjustments for tag loss, mortality, misreporting, and relocation efficiency based on returns from a sea-bed beacon tag left at the Bar Haven grounds. Multiyear homing was observed in 26% of cod. This study provides the first direct evidence that cod undertaking long-distance feeding migrations may home to a specific spawning ground in consecutive years, and a hypothesis for the slow recolonisation rates observed in North Atlantic cod stocks.

scholarly journals Fidelity of mature Icelandic plaice (Pleuronectes platessa) to spawning and feeding grounds

2005 ◽  
Vol 62 (2) ◽  
pp. 189-200 ◽  
Author(s):  
Jon Solmundsson ◽  
Jonbjorn Palsson ◽  
Hjalti Karlsson
Keyword(s):  
Fishing Effort ◽  
Migration Pattern ◽  
Spawning Season ◽  
Spawning Ground ◽  
Minimum Level ◽  
Pleuronectes Platessa ◽  
Feeding Area ◽  
One Year ◽  
Management And Conservation ◽  
Feeding Grounds

Abstract About 2200 plaice (Pleuronectes platessa) were tagged on spawning and feeding grounds off Iceland. The aim was to reveal the migration pattern of mature plaice and to estimate fidelity rates to spawning and feeding grounds. From a total of 183 plaice tagged on the spawning ground and recaptured in successive spawning seasons, 91% of males and 88% of females were recaptured within 30 km of the tagging site. From 55 plaice tagged in the feeding area and recaptured in subsequent feeding seasons, all males and 91% of females were recaptured within 30 km of the tagging location, supposedly after migration to distant spawning grounds as indicated by recaptures in the spawning season. When weighing the number of recaptures with a standardized fishing effort, a minimum level of fidelity to the spawning ground was estimated at 94% for the spawning season one year after tagging and at 72% for the second and third spawning seasons. Fidelity to the feeding area was estimated at 90% after one year and at 100% after two and three years from tagging. The study provides insights into the population structure of Icelandic plaice, relevant to the management and conservation of the population.

scholarly journals Spatiotemporal Changes of the Environmental DNA Concentrations of Amphidromous Fish Plecoglossus altivelis altivelis in the Spawning Grounds in the Takatsu River, Western Japan

2021 ◽  
Vol 9 ◽  
Author(s):  
Ryutei Inui ◽  
Yoshihisa Akamatsu ◽  
Takanori Kono ◽  
Minoru Saito ◽  
Seiji Miyazono ◽  
...  
Keyword(s):  
Economic Value ◽  
Environmental Dna ◽  
Spawning Season ◽  
Spawning Ground ◽  
Plecoglossus Altivelis ◽  
Spawning Grounds ◽  
Real Time Quantitative Pcr ◽  
Frequency Of Use ◽  
Western Japan ◽  
Japanese Rivers

The Ayu Plecoglossus altivelis altivelis is an amphidromous fish that is not only the most important commercial fishery species in Japanese rivers but also has a high economic value in recreational fishing. However, the degradation of its spawning grounds has caused a decrease in its abundance. In this study, we used environmental DNA (eDNA) to monitor the Ayu in the Takatsu River in Japan to (1) identify the spawning season in three known spawning grounds, (2) clarify changes in the main spawning grounds during the spawning season, and (3) discover unknown spawning grounds. We collected 1 L of the surface river water at three known spawning grounds nine times in 2018 and seven times in 2019 in the lower reaches of the Takatsu River. We also collected samples from seven unknown sites in 2018. The water samples were filtered through glass fiber filters. Total eDNA was extracted from each filtered sample and a Real-time quantitative PCR was performed with the specific primers and probe for Ayu. The results of the eDNA analyses showed that (1) the spawning season was in November in 2018 and in September in 2019. (2) One site was used as a spawning ground in both the early and the late spawning season, depending on the year. At the second site, the frequency of use changed year by year. The third site was the main spawning ground in the middle to late spawning season every year. From these results, we elucidated that some spawning grounds are used regularly every year, while the use of others varies year by year. (3) In five of the seven unknown sites, the nighttime eDNA concentrations were high at least once during the four surveys, suggesting that these sites may have functioned as spawning grounds. In particular, one site could be an important new spawning ground.

scholarly journals A note on the breeding season, sex ratio and embryonic development of the dogfish Scyliorhinus canicula (L.)

1952 ◽  
Vol 31 (2) ◽  
pp. 269-275 ◽  
Author(s):  
John E. Harris
Keyword(s):  
Sex Ratio ◽  
Embryonic Development ◽  
Breeding Season ◽  
Temperature Characteristic ◽  
Spawning Season ◽  
Spawning Ground ◽  
Teleost Species ◽  
Scyliorhinus Canicula ◽  
Different Temperatures

Records of nearly 2000 dogfish collected from the Ilfracombe region suggest that the spawning season of this fish starts in November and continues at least until July. This area probably represents a spawning ground into which the females migrate during the spawning season; the males follow them much later in April and May.Figures are given to show the time taken at different temperatures for the embryo to develop to a series of definite morphological stages; these suggest that the temperature characteristic of the development (µ = 20,000) is substantially the same as for several teleost species.

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