Onset of burying behavior concurrent with growth and morphological changes in hatchery-reared Japanese sandfish Arctoscopus japonicus

Abstract

Japanese sandfish generally bury themselves in the substrate, but only limited information is available on the behavior of the adults and juveniles (5–6 cm in total length) and essentially none for younger fish. While newly hatched larvae do not bury themselves, the fish size and morphological features of Japanese sandfish at the onset of burying behavior have not yet been identified. Due to the marked recent decrease in catches, development of techniques for the mass production and mass release of the juveniles of this species were initiated in 1983 by both Akita Prefecture and the Japan Sea–Farming Association (JASFA). Accumulation of the basic data about the biology of the larvae and juveniles is important in order to develop these techniques. Some information on growth, otolith daily increment, morphological development and feeding of the larvae and juveniles have been reported. This paper reports the fish size and morphological features of reared Japanese sandfish at the onset of burying themselves in the sand under experimental conditions. Fertilized eggs were obtained from the Akita Prefectural Fisheries Promoting Center on 15 December 1998. They were transported to the Notojima Station of the JASFA. On 8 February 1999, 60 000 newly hatched larvae were stocked in a 20 m net cage in the northern part of Nanao Bay and provided with night-time lighting from above. The larvae were raised from 0 to 75 days after hatching (DAH) with light-attracted zooplankton and a supplement of artificial dry pellets (Type B-400, B-700 and C-700; Kyowa Hakko Co. Ltd). For morphological observations and total length (TL), body length (BL), head length (HL), pectoral fin length (PFL), body depth (BD), preanal length (PAL), eye diameter (ED) and upper jaw length (UJL) measurements, larvae or juveniles were taken from the net cage at 5–10-day intervals. Morphological observations and TL measurement were made on the anesthetized samples (20 individuals in each sample), and body part measurements were made on the preserved samples (150 individuals in total) which were fixed in a 5% buffered formalin solution for 24–36 h and then transferred into a 70% ethanol solution. Due to the fixation which caused Japanese sandfish to shrink in size, TL before fixations were back-calculated as follows. Larvae or juveniles, ranging 13.3–35.5 mm TL before fixation, were taken from the net cage at an interval of 10 days from 5 DAH to attain the following equation:

DOI: 10.1111/j.1444-2906.2005.00955.x

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Cite this paper

@article{Morioka2009OnsetOB, title={Onset of burying behavior concurrent with growth and morphological changes in hatchery-reared Japanese sandfish Arctoscopus japonicus}, author={Taizo Morioka}, journal={Fisheries Science}, year={2009}, volume={71}, pages={242-244} }