On the problem of annual overfishing of the silver bream Blicca bjoerkna (Cyprinidae) in industrial fishing in the Astrakhan region

The silver bream Blicca bjoerkna and the small-sized common bream Abramis brama are characterized by external similarity, which contributes to manipulations with the substitution of one species (common bream) by another (silver bream) when taking into account the volume of industrial fishing in the Astrakhan region. This is due to the fact that in the period of spring fishing season during common bream spawning migration, the share of non-commercial common bream in commercial catches increases (to 20–30 %), the catch of which is limited in accordance with the Fishing Rules. In order not to exceed the allowable volume of by-catch of non-large common bream, fish producers register en masse catches of small-sized bream as a catch of silver bream, which causes significant damage to common bream fish stocks through oversampling of first-time maturing individuals of the population. In recent years, the share of non-commercial common bream recorded as a silver bream in May alone is 13–28% of its official catch during this period. In order to reduce the catch of first spawning common bream producers of non-commercial length on the water bodies of the Astrakhan region in the period from April 21 to May 20, it is recommended to introduce a ban on industrial fishing of silver bream.