MOSHER: SCALE FEATURES OF SOCKEYE SALMON 



(1919) reported a stock spawning in the Har- 

 rison River, B.C., near its junction with the 

 Eraser, B.C., and Krogius (1958) noted that they 

 occurred in the Kamchatka, Bolshaya, and Para- 

 tunka Rivers, USSR. The Nushagak River, 

 Bristol Bay, Alaska, had more than the usual 

 number of individuals of this age in 1961 (Koo, 

 1962b) but not enough fish from which to take 

 scales to furnish a frequency distribution. 



Except for the Rivers Inlet, B.C., fish, there 

 is little difference between areas in the features 

 of the scales of this freshwater age. Scales from 

 individuals taken from the Copper River, Alaska, 

 southward to the Eraser River, however, tend 

 to have a few more circuli in the first ocean zone 

 than those from Bristol Bay, Alaska. 



Eish of this age from Rivers Inlet and Smith 

 Inlet, B.C., can be identified to that geographical 

 area because the first ocean zone has the fine- 

 textured circuli typical of most fish from these 

 areas regardless of the freshwater age of the 

 fish (see Plates 9 and 14). 



AGE 1., 2., and 3., ALASKAN AREAS 



NORTH OF BRISTOL BAY (Plate 2; 



Tables 4, 5, 6, and 7) 



Production of sockeye salmon north of Bristol 

 Bay is small. The Kuskokwim River is the 

 largest producer in the area. In the Norton 

 Sound (Nome) and Kotzebue areas, few sockeye 

 salmon are found. However, they are heavily 

 exploited when present along with the other spe- 

 cies — by local residents for food and barter — 

 and thus are important in the local economy, 

 especially in some years. 



Very little is known of the migrations and 

 ocean distribution of sockeye salmon originating 

 in areas north of Bristol Bay. Of the many 

 thousands of sockeye tagged by Japanese and 

 United States scientists near the central Aleutian 

 Islands, only two tagged near Attn Island in 1958 

 and one tagged near Kiska Island in 1960 have 

 been returned from the area north of Bristol 

 Bay. All three were recaptured in the Kusko- 

 kwim River (Hartt, 1966). 



Presently it is not possible to identify the 

 origin of most of the sockeye salmon from this 

 area that are caught in offshore waters because 



the scales resemble those from many fish from 

 Asia and Alaska Peninsula. 



All freshwater age groups of sockeye salmon 

 from north of Bristol Bay have small freshwater 

 zones with few, often broken and irregular cir- 

 culi in each zone. Some scales show plus growth 

 (see Mosher, 1968, p. 251-254). 



Circuli of the first ocean zone are widely and 

 evenly spaced as in scales from Asian fish or 

 those from the Alaska Peninsula. The widest 

 spacing of circuli is usually some distance from 

 the freshwater zone. The number of circuli 

 varies from few, like fish from Bristol Bay, to 

 somewhat more, like fish from Asia or Alaska 

 Peninsula areas. 



AGE L, ASIA (Plate 3; Tables 4 and 5) 



Scales from fish from the Kamchatka, Ozern- 

 aya, and Bolshaya Rivers do not differ much be- 

 tween rivers. The freshwater zone is relatively 

 small with few, often broken and irregular cir- 

 culi. Often adventitious checks (false winter 

 marks, see p. 275, Mosher, 1968) occur in the 

 freshwater zone of these scales. Scales that I 

 have examined from fish captured in' the Okhotsk 

 Sea (which, according to Hanamura, 1966, may 

 be a mixture of runs from the Ozernaya and 

 Bolshaya Rivers and, at times, small numbers 

 of fish from the Okhota and the Kukhtuy Rivers 

 on the northern coast cf the Okhtosk Sea and 

 from other small producing streams of south- 

 eastern Kamchatka and the Kurile Islands) do 

 not differ much from those of the Ozernaya and 

 Bolshaya Rivers. Krogius (1958) reported that 

 the scales of fish from the Kukhtuy River are 

 similar to those of the Ozernaya River. Very 

 few fish of this freshwater age are found in the 

 Ozernaya River. 



Scales from fish from the Paratunka River 

 show two distinct types of freshwater growth; 

 those from Lake Blizhnee have a very small 

 freshwater zone with only a few, mostly broken, 

 irregular circuli; those from Lake Dalnee have 

 a moderately large to large freshwater zone with 

 numerous regular, unbroken circuli. Krogius 

 (1958) reported the favorable conditions for 

 growth of the fish in Lake Dalnee and the much 

 poorer conditions in Lake Blizhnee. 



169 



