1VRCI-IIVE

FISHERIES RESEARCH BOARD OF CANADA Translation Series No. 437

. INFORMATION ON THE BIOLOGY OF PINK SALMON ACCLIMATIZED IN THE BASINS OF THE WHITE AND BARENTS SEAS

By V. V. Azbelev and S. S. Surkov (Laboratory for the Production and Acclimatization of Marine MamMals, Fishes and Invertebrates) and A. A. Yakovenko (Murmansk Hydrometeorological Service)

Original title: Materialy po biologii gorbushi, akklimatiziruemd v basseine Belogo j Barentseva more.

From: Nauchno-tekhnicheskii Blûlleten PINRO, No. 2-3(20-21), pp. 37-38. 1962.

Preliminary translation by W. E. Ricker

Fisheries Research Board of Canada Biological Station, Nanaimo, B. C.

1963 Acclimatization of pink salmon in the Barents and White Sea basins has been under : way since 1956. The first return of adults was observed in 1960. . Study of the characteristics of the run of adult pinks in 1960 and 1961 was desirable in order to improve methodology in acclimatization. work , . hence rilutO's Laboratory of Production and Acclimatization studied the resultSof the pink salmon spawning of 1960 and analyzed the resulting downstream migration of young fish released from the fish-cultural establishments. This paper gives the main :4 conclusions with reference to the acclimatization of Pacific salmon in the north. In the Kola Peninsula rivers, the first returns of Pink salmon were obtained from young fish released not as fry, but as fingerlings that had been reared to a weight greater than the weight of the'young pinks.that migrate out of the rivers of the Far East. In 1960 and 1961 pink salmon returning to spawn gradually distributed themselves in an easterly direction and entered the White Sea from the Barents Sea. This leads us to suppose that the foraging area of the pinks of these two year-classes was located west of the Rybach Peninsula. To some extent this is supported by other data: (a)Pink salmon went to spawn not only into rivers of the Kola Peninsula, but also into rivers of Norway, Iceland and Spitsbergen. In 1960 the pinko appeared earlier in Norway than they did along our •Murman coast. (b)Only in the western part of the Barents Sea and in the Norwegian Sea do water temperatures exceed 3.5° even at the time of maximum warming, and hence can be considered Similar to the temperatures at which pink salmon of the east Kamchatka stock feed in the Pacific Ocean. (c)The times of maturity of the returning pink salmon varied in the same direction as they vary among the Atlantie salmon that forage in the Norwegian Sea. Hence we may postulate that these salmon had foraged in similar environmental conditions. Although the pink salmon adult migrants distributed themselves from the rivers of Spitsbergen on the north to those of Scotland on the south, the main bulk returned to spawn in rivers of the Kola Peninsula. Although no strict pattern of return to the rivers from which they had gone. to sea was observed, nevertheless rivers situated in the regions where hatcheries had reared these salmon received, the returning adults in somewhat greater numbers than did neighbouring rivers.

Pink salmon of the year-class that returned in 1961 differed from those of the previous year in being somewhat less in length, weight and fecundity, and also earlier in maturing. The spawning period of pink salmon that returned in 1960 occurred closer te winter, partly because of an early and sharp freeze-up in autumn. The main mass of these pinks spawned from September 22 to October 1, at water températures falling from 8.8 to 4.5°. Fart of them spawned at even lower temperatures, down to 2.5° and less. Water temperatures . close. to 0° were observed, in 1960, 5 to 20 days after the end of spawning. Pink salmon eggs of the 1960 year-class died en masse in all rivers and at all hatcheries; 100% mortality of eggs at early stages of development was observed only in the Titovka River, where hydrological conditions were particularly severe. Fry hatched in the hatcheries as well as in nature suffered from yolk-sac dropsy [vodianka zheltochnogo meshke] -- a disease that invariably results in death of the fry. In 1961 no downstream migration of young pink salmon -- in the usual meaning of this term -- was observed. In ascribing the mortality of pink salmon eggs and larvae (in the winter of 1960-61) to low water temperatures during the period of egg development prior to [page 381 the eyed-egg stage, we are arguing from the following facts: (a)In the Far East pink salmon spawn in the rivers in August and early September at water temperatures of 7 to 19°. Water temperatures close to 0 0 are reached at the middle of November, that is, when pink eggs have reached the eyed stage. (b)In the Far East spawning streams having low water temperatures (that is, the spring-fed streams) are not suitable for pink salmon spawning. (c)Incubation of pink salmon eggs of the 1960 brood gave good results in cases where development to the eyed stage took place at temperatures of 6-7 0 ; and from such eggs hardy young were obtained. (d)In 1961 pink salmon spawning in Kola Peninsula rivers began at the same time as in the Far East, and at water temperatures of 9.8-13.5°. In 1961 water temperatures close to 00 were reached in rivers of the Peninsula in the second half of November; from information available to February 1, 1962, develop- ment of those eggs has proceeded normally both in the hatcheries and in nature. (e)In the winter of 1960-61, 100% loss of eggs of pink salmon at early stages of development was observed only in the Titovka River, in the region where the freeze-up was earliest; in the rivers of the Tera coast, where zero water temperatures came later, cases of 100% mortality of eggs at early stages of development were comparatively rare, and they did not occur at all in the short Kolvitsa River that flows from a lake into Kandalaksha Gulf. Rivers of the Kola Peninsula differ from a majority of far-eastern rivers in having lower temperatures in the second and third 10-day periods of September, in October, and in May; that is, in the months during which eggs are developing and the young are beginning to swim. In years of late maturation of the pinks, or years of early freeze-up, fish culturists might be able to offset the unfavourable effects of low water . temperature on eggs during early developmental stages by adopting the method of incubating them in damp air. But if this is done, in the spring of cold years it would be necessary) in order to permit the release of the young at the corrdet temperature, to provide rearing facilities for the young fish with water • temperatures no lower than the 3.0° at which young pinks will start to feed actively. Artificial propagation must be regarded as an important means of producing pink salmon for acclimatization, because theiinatural reproduction can produce an abundant year-class only in years that are close to average in hydrometeorological conditions and' in which an adequate number of adult fish appear that mature early in the season.

The fact that from the same number of young pinks released from arctic hatcheries in 1959 and 1960, quite different numbers of adult fish returned, shows that in our north environmental conditions for reproduction affect the abundance of young fish going to sea to the same extent as happens in the Far East. The experiment in acclimatizing Pacific salmon in the north, and the experience' of Soviet acclimatizers, shows that the time has come to get. away from single experiments . designed to enrich the fauna with a few valuable species, and instead to set up an overall general plan for the reorganization and reconstruction of living nature,not only in inland basins, but also in the sea. To work out such plans requires an analysis of available materials on the ecology ofthe speàes -- native and imported. This . process.is' very laborious and might, be completed Only over several yearàF time. Inasmuch as there exist separate . stages in acclimatizationworkestablishing the biological foundation, developing methode, - etc. -- we must also establish a general plan for . reconstruction of the fauna of the waters of Our north.