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Some biological aspects of siamese algae eater, Gyrinocheilus aymonieri (Tirant, 1884) in the Yom river, Sukhothai province  [2002]

Patipath Apitanakul(Department of Fisheries, Bangkok (Thailand)) Wirun Wetchakul(Department of Fisheries, Bangkok (Thailand))

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Abstract
Some biological aspects of Siamese algae eater, Gyrinocheilus aymonieri (Tirant, 1884), was studied at the Yom River, Sukhothai Province, during December 1997 to November 1998. Samples of 915 specimens of 404 males and 511 females, with the total length of 11.4-18.0 cm and the weight of 17.13-48.75 g were monthly collected from 3 stations. The results showed that body shape of G. aymonieri was elongate, sub-cylindrical and the percentage of body depth to standard length was 17.24-20.00. Its head was short and the percentage of head length to standard length was 26.32-32.17. It had no osseous rays. Doral fin, pectoral fin and pelvic fin comprised with 9 1/2, 13 and 9 soft rays respectively. The number of lateral line scales was 38-41. This fish was normally found in schooling attached on submerged solid surfaces in flowing water. The analysis of stomach contents showed that this fish was herbivorous with its ratio of body length to intestine of 1:14.2. Its stomach contained 73.3 percent of algae and phytoplankton, 13.1 percent of plant fragments, and 13.6 percent of gravel debris. Sex ratio between male and female was 1:1.26. Three equations of length and weight relationship of unclassified sex, males and females were log W=2.7439 log L-1.6239 (R sup(2) = 0.8750, p LT 0.01). log W = 2.5884 log L-1.4552 (R sup(2) = 0.8949, p LT 0.01) and log W = 2.9933 log L.-1.9028 (R sup(2) = 0.9149, p LT 0.01), respectively. Gonadal development study of Siamese algae eate
r indicated that their spawning season occurred during April to August. The egg was semibuoyant, round in shape and grayish-green colour. The average fecundity was 50,128+8,116. The peak of GSI was found in July in females and August in males. The relationship between fecundity and weight was log F = 0.6734 log W + 3.5159 (R sup(2)=0.8972. p LT 0.01), and fecundity and length was log F=1.6885 log L + 2.6574 (R sup(2) = 0.8825, p LT 0.01) The estimate of growth parameters were 1.28 per year of growth constant (k), 22.6 cm of the maximum theoretical length (L alpha), 3.50 per year for total mortality (Z), 2.21 per year for natural mortality (M), and 1.29 per year for fishing mortality (F). The level of exploitation rate (E) was 0.37.
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Other subjects

  • rivers
  • freshwater fishes
  • biology
  • habitats
  • GYRINOCHEILUS AYMONIERI
  • thailand
  • behaviour
  • animal morphology
  • population dynamics
  • reproduction

From the journal

Warasan Kan Pramong

ISSN : 0125-6297

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