open access

https://doi.org/10.14943/lowtemsci.80.445

https://hdl.handle.net/2115/84947

Age, size frequency, and population density of white-spotted char Salvelinus leucomaenis inhabiting in Ozegahara streams

日本語

white-spotted char

2022-03-31

低温科学第80巻編集委員会

Low Temperature Science

80

445-451

In this study, capture surveys were conducted in eight tributaries and the main stream flowing though Ozegahara to obtain basic information of White spotted char Salvelinus leucomaenis on the size frequency, age and population density. As a result, 229 char were captured and the average body size was 15.42 ± 5.57 cm for males and 14.21 ± 4.05 cm for females. Age was assessed from scales and ranged from 0 to 6 years, with males averaging 2.67 ± 1.33 years and females 2.20 ± 1.03 years. Comparisons of body size showed no differences between males and females, although differences were observed between ages. Fish densities in the eight tributaries averaged 0.035 fish m-2 (range: 0.006-0.097 fish m-2), which was low compared to other rivers. The mean sex ratio in each tributary was 0.58 (male / (male + female)), and the proportion of males tended to be higher in the upper reaches and smaller tributaries than in the lower reaches. Further elucidation of the ecology of char inhabiting Ozegahara is desirable, taking into account the amount of attached algae, aquatic insects, and falling insects in each tributary and the entire river ecosystem.

紀要論文

Version of Record

1880-7593