scholarly journals ON EFFECT OF THE SIZE OF SOCKEYE SALMON ONCORHYNCHUS NERKA SMOLTS ON TIME OF THE SCALE SCLERITE FORMING DURING IMPLEMENTING OF THEIR COMPENSATORY GROWTH IN THE YEAR OF MIGRATION TO THE SEA FROM LAKE AZABACHYE (KAMCHATKA RIVER BASIN)

2018 ◽  
Vol 193 ◽  
pp. 88-98 ◽  
Author(s):  
V. F. Bugaev

The Kamchatka River basin is the reproduction area for the secondary large Asian stock of sockeye salmon, one of the most valuable species of pacific salmons. Several major local stocks and groups of minor stocks occupy the basin, the main of them are: i) A — the aboriginal stock in Lake Azabachye (in the lower Kamchatka basin) which juveniles stay two winters in the lake and migrate to sea in the age 2+; ii) E — the transit group of local stocks spawning in the middle and lower tributaries of the Kamchatka which juveniles enter to Lake Azabachye for feeding and wintering and migrate to the sea after the wintering in the age 1+. The latter underyearlings get an additional mark on the scale (less than typical annuli) entering the Lake because of the feeding conditions change. That’s why almost all (90–95 %) juveniles have two zones of dense sclerites (ZDS) when leave Lake Azabachye, no matter of their 2+ or 1+ age. By the measurements in 1979–1987 of the smolts with two ZDS (A + E) in the year of their migration from Lake Azabachye to the sea, each sclerite on scale had formed in 6.61 days, on average, while the smolts staying in the lake for freshwater feeding (with one ZDS) formed each sclerite in 12.00 days, on average. Correspondingly, the migrants had wider distance between the sclerites (4–5 mm), as compared with those of non-migrants (2.0–2.5 mm) (with 150 times magnification). The aboriginal migrants demonstrate the effect of real compensatory growth in the year of emigration that is reflected in the scale structure as wider intersclerite distances. Negative dependence between the size of smolts and rate of their sclerites forming is observed on the data of 1987–2016 for the aboriginal stock A: the bigger the smolts at age 2+, the lower the rate, the longer the time of new sclerite forming, and the narrower the distance between sclerites, and vice versa. This dependence is interpreted as additional environment-dependent adjustment of the growth rate for the smolts with compensatory growth for their better adaptation and survival.

2018 ◽  
Vol 195 ◽  
pp. 128-139
Author(s):  
V. F. Bugaev

Two groups of juvenile sockeye salmon are feeding in Lake Azabachye. They belong to the 2nd order stock of the lake (stock A) and to other 2nd order stocks of middle and down stream tributaries of the Kamchatka River which underyearlings migrate into the lake for feeding and wintering (group E). The main part of the stock A leaves the lake to the sea at the age 2+ (mainly 2.3) and the youngsters of the group E migrate to the sea at the age 1+ (mainly 1.3). The body length and weight parameters of the stock A smolts at the age 2+ and the group E smolts at the age 1+ could be similar or dissimilar in particular years. The maximal difference between the smots of these stocks is observed in the years with higher body length and weight for the stock A. Mean for 1979–2016 length and weight of smolts at abovementioned ages are evaluated as 98.42/87.46 mm and 10.40/7.38 g for the A/E stocks. For the stock A, statistically signifcant positive correlation is noted between size-weight parameters of smolts in the years of emigration and their abundance in the years of mass return. However, the regression has a shift between the periods of emigration/return of 1979–2000/1982–2003 and 2003–2013/2006–2016. The correlation is higher for the frst period (r = 0.820; P < 0.001 for body weight and r = 0.797; P < 0.001 for body length, n = 16) than for the second one with higher abundance (r = 0.669; P < 0.05 for body weight and r = 0.711; P < 0.05 for body length, n = 11). On opposite, the returns of the group E depend weakly on size-weight parameters of its smolts for the period of emigration/return of 1979–1997/1982–2000 (no data for return in 1999) and the dependence is insignifcant for the period of 2000–2013/2003–2016.


2015 ◽  
Vol 183 (4) ◽  
pp. 27-40
Author(s):  
Anastasia M. Khrustaleva ◽  
Natalia V. Klovach

Intrapopulation differentiation of the two large population systems of sockeye salmon from the Kamchatka and Apuka Rivers in East Kamchatka is considered by analysis of 45 SNP loci. Four samples were analyzed: 2 from the lower Kamchatka River (20 specimens for early run and 100 specimens for late run), 1 from the basin of Lake Azabachye belonged to the same system ( n = 81), and 1 from the Apuka River (53 specimens for mass run). No genetic differences were found between the samples for early run and late run in the Kamchatka River, though the late run sockeye could be subdivided into two genetically and morphologically different groupings, probably spawning in different biotopes: the first represented by small, fast-growing and early maturing individuals and the second represented by bigger, late maturing ones. For the Apuka River, the hypothesis was corroborated on simultaneous run of two genetically and ecologically different groupings of sockeye salmon: they differed statistically by allele and genotype frequencies of SNP loci. The intrapopulation differentiation is comparable or even exceeds the interpopulation differences for sockeye salmon of neighbor populations, though it is unobvious for geographically remote populations. This differentiation is supposedly caused by differences of natural selection in some SNP loci for different habitats.


1969 ◽  
Vol 26 (9) ◽  
pp. 2363-2394 ◽  
Author(s):  
J. R. Brett ◽  
J. E. Shelbourn ◽  
C. T. Shoop

The growth of young sockeye salmon (Oncorhynchus nerka) was studied at temperatures ranging from 1 to 24 C in relation to rations of 0, 1.5, 3, 4.5, and 6% of dry body weight per day, and at an "excess" ration. Optimum growth occurred at approximately 15 C for the two highest rations, shifting progressively to a lower temperature at each lower ration. The maximum growth rate for sockeye 5–7 months old was 2.6%/day; that for fish 7–12 months old was 1.6%/day. At 1 C a ration of 1.5%/day was sufficient to provide for a maximum growth rate of 0.23%/day. The maintenance ration was found to increase rapidly above 12 C, amounting to 2.6%/day at 20 C. No growth took place at approximately 23 C despite the presence of excess food.Isopleths for gross and net food-conversion efficiencies were calculated. A maximum gross efficiency of 25% occurred in a small area with a center at 11.5 C and a ration of 4.0%/day; a maximum net efficiency of 40% occurred within a range of 8–10 C for rations of 1.5%/day down to 0.8%/day, the maintenance level.Gross body constituents changed in response to the imposed conditions, varying in extreme from 86.9% water, 9.4% protein, and 1.0% fat for starved fish at 20 C to 71.3% water, 19.7% protein, and 7.6% fat on an excess ration at 15 C.It is concluded on the basis of growth and food-conversion efficiency that temperatures from 5 to 17 C are most favorable for young sockeye, and that a general physiological optimum occurs in the vicinity of 15 C.


1975 ◽  
Vol 32 (11) ◽  
pp. 2103-2110 ◽  
Author(s):  
J. R. Brett ◽  
J. E. Shelbourn

The specific growth rate of young sockeye salmon (Oncorhynchus nerka) was studied for a period of 7 mo to determine the effect of body weight when on restricted and unrestricted rations. It was hypothesized that a restricted ration would result in a fixed growth rate until size became a limiting factor reducing food demand below the prescribed level and thereby reducing growth rate. The results support the hypothesis, with the possible exception that growth rate may increase slightly during the period of fixed ration. On excess ration the specific growth rate fell from 3.6% weight per day (2.4 g mean weight) to 1.0% weight per day (37 g mean weight); intermediate constant growth rates accompanied the periods of fixed ration, inflecting to lower rates subsequently. The general equation log G = a + b log W (where G = specific growth rate, and W = weight in grams) was found to apply to a number of salmonids. The slope value of b = −0.4 ±.04 appears to characterize the family, with the intercept a taking on different values according to the varying capacity for rapid growth.


1973 ◽  
Vol 30 (4) ◽  
pp. 499-507 ◽  
Author(s):  
P. W. Webb ◽  
J. R. Brett

Tests were performed at 15 C, pH 6.8, and dissolved oxygen values of 90–100% air saturation. Growth rate and conversion efficiency were measured by feeding a ration level of 15% body dry weight/day to underyearling sockeye salmon (Oncorhynchus nerka) held at sodium pentachlorophenate (PCP) concentrations of 0, 1.14, 1.99, 3.49, 7.16, 13.60, 27.73, 31.57, and 47.18 ppb. Swimming performance was measured at PCP concentrations of 0, 7.21, 19.00, and 50.00 ppb. The 96-hr LC50 was 63 ppb PCP. Growth rate and conversion efficiency were almost equally affected by PCP, the EC50 values being 1.74 ppb for growth rate and 1.80 ppb for conversion efficiency. This is approximately 2.8% of the 96-hr LC50. Swimming performance was unaffected by PCP at the concentrations used.


2019 ◽  
Vol 197 ◽  
pp. 194-207
Author(s):  
V. V. Pospekhov ◽  
K. V. Kusenko

Morphology of phylonems infesting whitespotted char Salvelinus leucomaenis and sockeye salmon Oncorhynchus nerka in Lake Kisi at the northern coast of the Okhotsk Sea is described for the first time. Sockeye was infected with adults of Philonema oncorhynchi Kuitunen-Ekbaum, 1933 and larvae of other nematode species (Philonema sp. II), and char — with adult dracunculoid nematode designated as Philonema sp. I. This Philonema sp. I differs considerably from Ph. oncorhynchi by number of reproductive papillae, their distribution, and structure of cuticular appendices on the caudal end of males. Larvae of Philonema sp. I (1st stage) and Philonema sp. II (3rd stage) are described, as well. These new data allow to reconsider the species belonging of nematodes infesting chars (Salvelinus) in North-East of Russia, which are identified now mostly as Ph. oncorhynchi.


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