Estimating target strength of young chum salmon (Oncorhynchus keta)

2022 ◽  
pp. 1-5
Author(s):  
Kenji Minami ◽  
Hokuto Shirakawa ◽  
Yohei Kawauchi ◽  
Huamei Shao ◽  
Makoto Tomiyasu ◽  
...  
Keyword(s):  
Bering Sea ◽  
Chum Salmon ◽  
Fork Length ◽  
Target Strength ◽  
Oncorhynchus Keta ◽  
Biomass Estimation ◽  
Fishery Resource ◽  
Chum Salmon Oncorhynchus Keta ◽  
Acoustic Methods ◽  
The Bering Sea

Although chum salmon (Oncorhynchus keta) is an important fishery resource in Japan, acoustic methods cannot be applied to biomass estimation because the target strength (TS) is unknown. This study clarified the TS for each fork length (FL: 5.5–33.5 cm) of young chum salmon inhabiting the Japanese coastal area to the Bering Sea by measuring free-swimming fish. The size dependences of the TS values were TSmean = 20 log10 FL – 68.0, for both 38 and 120 kHz. This facilitated the estimation of biomass of young salmon using acoustic methods.

A genetic analysis of meristic and morphometric variation in chum salmon (Oncorhynchus keta) at three different temperatures

1990 ◽  
Vol 68 (2) ◽  
pp. 225-229 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
Chum Salmon ◽  
Fork Length ◽  
Oncorhynchus Keta ◽  
Meristic Characters ◽  
Morphometric Variation ◽  
Morphometric Characters ◽  
Chum Salmon Oncorhynchus Keta ◽  
Different Temperatures ◽  
Character Variation ◽  
Temperature Interactions

A nested mating design was used in which 10 males were mated with 20 female chum salmon (Oncorhynchus keta), and individuals from each of the 20 families were maintained at 6, 10, and 14 °C from egg fertilization until juveniles reached a fork length of about 61 mm. Variation in 11 morphometric and 3 meristic characters was evaluated. Rearing temperature had a marked effect on juvenile morphometric variation, enough to assign correctly 91% of the juveniles reared at 14 °C, 90% of the juveniles reared at 10 °C, and 95% of the juveniles reared at 6 °C. The addition of meristic character variation increased the classification accuracy to 97, 92, and 96%, respectively. As rearing temperatures increased, the observed levels of fluctuating asymmetry for the three meristic characters increased. Morphometric characters tended to have lower heritabilities than did meristic characters. Genotype–temperature interactions generally accounted for between 10 and 30% of observed phenotypic variation for most characters.

Aggression and Variation in Growth of Chum Salmon (Oncorhynchus keta) Juveniles in Seawater: Effects of Limited Ration

1987 ◽  
Vol 44 (1) ◽  
pp. 192-197 ◽  
Author(s):  
Michael W. Davis ◽  
Bori L. Olla
Keyword(s):  
Growth Rate ◽  
Chum Salmon ◽  
Condition Factor ◽  
Fork Length ◽  
Oncorhynchus Keta ◽  
Average Growth ◽  
Ration Level ◽  
Chum Salmon Oncorhynchus Keta ◽  
Schooling Fish ◽  
Coefficients Of Variation

Chum salmon (Oncorhynchus keta) were grown in groups of 10 for 40 d on three limiting ration levels, and weight and fork length were measured at day 0 and day 40. Variation in growth of fish within a cohort was estimated from calculation of coefficients of variation for weight, fork length, condition factor, and growth rate. Average growth was significantly less at the lowest ration level than at the two higher levels, where average growth did not differ significantly. However, variation in growth (growth depensation) was significantly higher at the lowest and intermediate ration levels than at the highest ration level; we surmise that this higher variation is associated with increased competition and the disproportionate acquisition of food by larger fish. Aggressive behavior was most intense at the highest ration level. Chum salmon apparently show characteristics of a schooling fish while showing aggression, behaviors that are generally viewed as mutually exclusive.

Timing and Relative Intensity of Size-Selective Mortality of Juvenile Chum Salmon (Oncorhynchus keta) During Early Sea Life

1982 ◽  
Vol 39 (7) ◽  
pp. 952-957 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Relative Intensity ◽  
Chum Salmon ◽  
Size Range ◽  
Fork Length ◽  
Open Water ◽  
Oncorhynchus Keta ◽  
Selective Mortality ◽  
Chum Salmon Oncorhynchus Keta ◽  
Time Period ◽  
Juvenile Chum Salmon

Available evidence indicates that mortality of juvenile salmon during early sea life is high and probably size dependent. I used scale analysis to determine the timing and relative intensity of size-selective mortality in chum salmon (Oncorhynchus keta) during early sea life. Significant size-selective mortality could be demonstrated only over the time period that the fish were laying down circuli 2–4 on their scales. The relative intensity of mortality for different sizes of fish suggested that mortality was strongly size selective over the size range 45–55 mm fork length. No particular mortality agent could be identified, but the size range involved corresponds with the size at which chum salmon move from very shallow water and nearshore habitat to open water pelagic habitat.Key words: size-selective mortality, salmon, early sea life

Influence of Deteriorating Water Quality on Growth and Development of Chum Salmon (Oncorhynchus keta) Larvae in a Japanese-Style Keeper Channel

1983 ◽  
Vol 40 (12) ◽  
pp. 2098-2104 ◽  
Author(s):  
R. A. Bams ◽  
C. N. H. Lam
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Chum Salmon ◽  
Fork Length ◽  
Low Flow ◽  
Differential Mortality ◽  
Oncorhynchus Keta ◽  
Chum Salmon Oncorhynchus Keta ◽  
Stage Of Development ◽  
Standard Channel

Chum salmon (Oncorhynchus keta) larvae were incubated in gravel-filled cages placed in two experimental Japanese-style keeper channels having 40 and 80 L/min total flow, at three successive locations having 0, 46 000, and 92 000 eggs (or alevins) upstream. Minimum dissolved oxygen was 6.21 mg/L, maximum un-ionized ammonia was 0.18 μg/L, pH varied from 7.18 to 6.83, and temperature ranged from 7.8 to 8.2 °C. Preemergent fry showed small but significant decreases in mean fork length, with increasing distance along both channels 50 d after hatching. Weights decreased similarly but nonsignificantly in both channels. Stage of development (expressed as KD-index) was constant in all locations except the bottom location of the low-flow channel, which showed a significant delay. Survival was uniformly high with no differential mortality among locations or flow rates. We conclude that deteriorating water quality measurably reduced larval development rate, growth rate, and yolk-conversion efficiency. Main effective factor was dissolved oxygen. Standard channel loading and flow criteria are adequate for short incubation channels only.

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