Fishery return of Herring-black-backed shad Alosa kessleri kessleri in the Volga river in 2010–2014
2017
Pyatikopova, O.V. | Voynova, T.V. | Raspopov, V.M.
The work presents the results of observations to the spawning migration of spawners of herring-black-backed shad in the Delta of the Volga River in 2010–2014. The article gives the assessment of the effectiveness of spawning of this species. It is estimated the quantity of spawners of the species at age 3 and 4 years old from the spawning stock and it is carried out a comparison with fishery stock. Thus, the most authentic estimations are obtained from species of 4 years old, because not all individuals of 3 years old g to the spawning. According to the obtained data it is estimated the coefficient of the entry into the fishery of individuals from 3 to 4 years old. According to the number of generations it is estimated the coefficient of the fishery return on the equation of regression. The calculations have shown that the coefficient of the fishery return is higher with a small (in number) generation. The analysis of a spawning stock of the herring-black-backed shad for 5 yeas (2010–2014) evidences about the fact, that the coefficient of the fishery return 0,02, used in estimations of number of the species to the feature, is not justified. The calculations of the coefficient values of the entry into the fishery of individuals of 3 and 4 yeas old, make up 60% of the spawning stock, have shown that in comparison with the previously accepted values they are reduced in 2,5–3,6 times
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