この論文を読む／探す
抄録
魚体が網地に締め付けられながらも網抜けできる目合を検討するために,締め付けによるくびれた状態での最大胴周長,その締め付けを突破させることのできる引き抜き力を測定する装置を作製した。これを用いて,締め力を0.49 Nから2.94 Nまで4段階に変化させたときの,ホッケの最大胴周長および引き抜き力を測定した。また,ホッケの遊泳力も測定した。引き抜き力とホッケの遊泳力を比較すると,体長30 cm 前後のホッケの遊泳力では網目から1.96 N程度の締め付けがかかれば網目を突破できないが,0.98 N程度の締め付けならば突破できると考えられた。そのときの魚体くびれ率の平均値は97.3%であった。
In order to investigate the relationship between the girth of fish and the appropriate mesh size when the fish body passes through the mesh in case of wedged capture, a new device for measuring the maximum girth was developed. This device is capable of simultaneously measuring both the maximum girth of the fish body and the traction force as the force required to pass through the artificial mesh which is contracted by an attached load. Using the device, the maximum girth and traction force were measured for arabesque greenling Pleurogrammus azonus of about 30 cm standard length, as the contracted load was increased gradually in four steps from 0.49 N to 2.94 N. When the contracted loads were 0.98 N and 1.96 N, the mean forces of traction were 5.19 N and 10.01 N, respectively. The mean swimming power of arabesque greenling was about 6.57 N. These results suggest that arabesque greenling would not pass through a mesh contracted by a load of about 1.96 N, but would pass through a mesh contracted by a load of about 0.98 N. When the contracted load was 0.98 N, the shortening ratio of the girth was 97.3%.
