What’s the effectiveness of stocking actions in small creeks? The role of water discharge behind hatchery trout downstream movement

PeerJ

article

Stefano Brignone¹  Vanessa De Santis¹  Tiziano Putelli²  Christophe Molina²  Armando Piccinini³  Richard A. Carmichael³  Pietro Volta¹ 

[1] National Research Council CNR-IRSA;Ufficio della caccia e della pesca;Biomark

关键词: Fish stocking;    Stock enhancement;    Passive integrated transponder (PIT);    Fish telemetry;    Fish movement;    Brown trout;   

DOI  :  10.7717/peerj.14069

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Fish stocking to enhance freshwater fisheries or to improve the conservation status of endangered fish species is a common practice in many countries. Little is known, however, of the effectiveness of these practices in spite of the high efforts and investments required. The movement of subadult/adult hatchery-released brown trout Salmo trutta L. was studied by passive telemetry in a small tributary of Lake Lugano (i.e., Laveggio Creek, Canton Ticino, Switzerland). Hatchery fish, together with some resident wild individuals sampled during electrofishing surveys, were tagged with Passive Integrated Transponders (PIT) tags. Hatchery fish were released upstream and downstream a submersible monitoring antenna, which was anchored to the streambed in a pass-over orientation. The number of hatchery fish detected daily by the antenna (divided between fish released upstream and downstream the antenna) was analyzed in relation to the daily water discharge, to search for similar patterns in their fluctuation over time. Only the movement of fish released upstream the antenna displayed a significant relationship with water discharge, with the highest number of fish detected during periods of high-water flow, occurring after heavy rains. High-water discharge events had a significant role in hatchery trout downstream movement in our study site, likely acting as a driver for the downstream migration to Lake Lugano. Such events contributed to the poor effectiveness of stocking actions in this small tributary, providing further evidence against stocking strategies based on subadult/adult fish.

【 授权许可】

CC BY