Distribution of overwintering Pondloaches (Misgurnus anguillicaudatus) in rice fields in Japan
Hiroshi Jinguji, Katsuya Miyai, Moono Shin
The 2020 Korean Society of Agricultural Engineer Annual Conference in Web, 2020年10月
Abstract
The Pond loach, Misgurnus anguillicaudatus (Cantor, 1842), is widespread in rivers, ponds, swamps and rice fields in Korea and Japan. Although M. anguillicaudatus is a common fresh water fish, it is classified as near threatened in the Red Data list published by the Ministry of Environment, Japan. Korea and Japan have a culture of consuming loaches and the decrease in loach populations may cause the loss of traditional food culture. This study examined the optimal environmental conditions for overwintering loaches in rice fields. The study site was located in Osaki-machi in Miyagi Prefecture, Japan. We randomly collected paddy surface soil (30 cm depth) from 20 rice fields, and M. anguillicaudatus specimen s from a p it in a dry d rain age canal. Misgurnus anguillicaudatus specimens were kept individually in beakers, and body mass and standard length were measured. A total of 19 M. anguillicaudatus specimens were collected from seven rice fields and 31 specimens were collected from the drainage canal. The M. anguillicaudatus that were overwintering in the soil were concentrated in shallow water near the water inlets or outlets of the rice fields. The mean standard length of all M. anguillicaudatus collected in the rice fields and in the pit in the drainage canal was 56.5Å}11.7mm and 49.9Å}10.5mm, respectively. There was no significant difference in the body length of the two groups. Our findings suggest that M. anguillicaudatus overwinters in wet and poorly drained rice fields.
Key words : Misgurnus anguillicaudatus, overwinter, Rice fields, standard length, body mass