Fundamental Experiment to Determine Escape Countermeasures for Frogs Falling into Agricultural Canals

DOI Web Site 2 Citations 17 References

Bibliographic Information

Other Title
  • 農業水路に転落したカエル類の脱出対策に関する基礎的実験
  • 農業水路に転落したカエル類の脱出対策に関する基礎的実験--トウキョウダルマガエルが脱出しやすいスロープの傾斜角及び水路の水理条件
  • ノウギョウ スイロ ニ テンラク シタ カエルルイ ノ ダッシュツ タイサク ニ カンスル キソテキ ジッケン トウキョウダルマガエル ガ ダッシュツ シヤスイ スロープ ノ ケイシャカク オヨビ スイロ ノ スイリ ジョウケン
  • —トウキョウダルマガエルが脱出しやすいスロープの傾斜角及び水路の水理条件—
  • — Angle of wall slope and hydraulic conditions of agricultural canals from which Tokyo Daruma Pond Frogs (<i>Rana porosa porosa</i>) can escape easily —

Search this article

Abstract

Frogs often drown in agricultural canals with deep concrete walls, which are installed commonly in paddy fields after land improvement projects in Japan, because they cannot escape after falling into the canal. Therefore, countermeasures that enable frogs to escape from canals are required in some rural areas. An experimental canal with partially sloped walls was used as an escape countermeasure to investigate the preferable angle of slope for the walls, water depth and flow velocity that enables Tokyo Daruma Pond Frogs (Rana porosa porosa), which have no adhesive discs, to easily escape.<br>Walls with slopes of 30-45 degrees allowed 50-60% of frogs to escape from the experimental canals, frogs especially easily climbed the 30 degree sloped walls. When the water depth was 5 cm or flow velocity was greater than 20 cm/s, approximately 80% of the frogs moved downstream and reached the sloped walls because the frogs' toes did not reach the bottom of the canal. However, if the depth was 2 cm and the flow velocity was 5 cm/s, only 4% of the frogs climbed the sloped walls because they could move freely. The frogs appeared to not be good at long-distance swimming and could not remain a long-time under running water. Therefore, walls sloped less than 30 degrees and control of both water depth and flow velocity appears important for enabling frogs to easily escape from canals.

Journal

Citations (2)*help

See more

References(17)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top