Temperature effects on larval development and occurrence of metamorphosis-related morphological abnormalities in hatchery-reared spotted halibut Verasper variegatus juveniles

M. Aritaki, K. Ohta, Y. Hotta-2004

Nippon Suisan Gakkaishi, 70(1): 8-15

Abstract:

The occurrence of metamorphosis-related abnormalities under different rearing water temperatures (9-21 °C) was examined in hatchery-reared juveniles of spotted halibut Verasper variegatus. The growth and development of the larvae were accelerated at higher temperatures. After completing metamorphosis, juveniles were categorized into three morphological types (normal, pseudoalbino and ambicolored fish) based on eye location and body color (pigmentation). The temperature spectrum of the occurrence of these three morphological types was consistent among three experiments carried out in different years, and the normal fish occurred most frequently at 18°C, pseudoalbino fish at 12°C and ambicolored fish at 21°C. The morphological characteristics of both body sides (left and right) in pseudoalbino and ambicolored fish were similar to the blind side and ocular side, respectively, of normal fish, suggesting the occurrence of abnormal asymmetrical development in either body side.
These results suggest the possible involvement of rearing temperature, possibly through the timing of metamorphosis and/or the speed of larval growth/development, in the asymmetrical differentiation of left and right body sides during metamorphosis.

(Miyako Station, National Center for Stock Enhancement, Miyako, Iwate 027-0097, Japan)

home