Abstract
Salmon fishes of the Salmo genus are the important object for fishing, artificial breeding and sport fishing. Currently, for some reasons, the size of the salmon population is in a depressed state. For some salmon fish population in the north of Russia became possible to solve some problems of their preservation with the development of artificial reproduction. However, the quality of juvenile salmon reproduced in the factory, the transportation and release of juveniles are not effective enough therefore the most of the fishes die after release them into natural water soon. The cause of their death is the lack of physical strength and endurance of juveniles in river conditions. At present moment the normative criterion for the quality of juveniles is a hinge of released fishes. One of the alternatives for assessing the quality of whitebaits can be the use of device “Fish Sprint”, whose action is based on the registration of the traction force by a dynamometer developed during the fish motor reaction to the anode in response to the action of a direct or current electric field (anode reaction). Researches have shown that the pulling power of fishes changes significantly in the seasonal aspect and determines primarily by the temperature of the habitat. For juvenile Atlantic salmon it is observed a gradual increase of physical strength at a temperature from 3.5 to 16 ° C, and in the future the pulling force remains almost unchanged. The physical strength of wild spotted trout (age 2+ - 4+), living in river conditions, was higher, compared with factory ones of Atlantic salmon. Salmon juvenile with the same morphological indicators of length and mass, living in natural conditions (rivers) develops physical strength higher twice in comparing juvenile grown in the factories.
Highlights
Fishes of the genus Salmo are important items for commercial fisheries, aquaculture, and sport fishing
The quality of hatchery-reared juvenile salmonids, their transportation and release stocking systems have flaws, considering that most of the fish die soon after being released into the wild. The reason for these mortalities is the lack of physical strength and resilience of the juveniles in the river
A possible alternative for assessing the quality of fry is to use the “Fish Sprint” device, whose operating principle is the registration by a dynamometer of the traction force developed by the fish moving towards the anode in response to the action of direct-current electric field
Summary
Прибор «Фиш-спринт» относительно прост в исполнении и включает в себя следующий комплект (рис.): – пластиковый лоток с водой для рыбы, размеры 50 × 15 × 10 см; – электроды постоянного тока (анод (+) и катод (–)) в виде латунных пластин, которые подключены к источнику напряжения (аккумуляторной батарее); – монофильная леска (d – 0,1 мм) с маленьким «крокодилообразным» зажимом для рыбы; – динамометр с тарировкой до 200 г, которую можно в процессе эксперимента изменять в зависимости от размеров и силы тяги рыбы; – источник питания (аккумуляторная батарея), позволяющий создавать электрическое поле постоянного тока до 1 В на 1 см длины. После включения электрического тока у экспериментальной рыбы мгновенно возникает анодная реакция, и она с максимальным усилием сразу устремляется к аноду. Так подачу тока повторяют 2–3 раза для регистрации на динамометре максимального значения силы тяги. Но несколько травмированную рыбу выпускали в реку (в полевых условиях) либо в бассейн (если работа идет на рыбоводном заводе)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
