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Use of dual‐beam acoustic technique for detecting young whitefish, Coregonus sp., juveniles: first experiments in an enclosure
Author(s) -
Ponton D.,
Meng H. J.
Publication year - 1990
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1990.tb04328.x
Subject(s) - biology , enclosure , fish <actinopterygii> , fishery , coregonus , target strength , dusk , zoology , ecology , telecommunications , computer science
We tested the possibility of using a high‐frequency, BioSonics, dual‐beam, acoustic system with an upwards‐looking transducer to detect very young whitefish, Coregonus sp., juveniles. These first experiments were conducted in an enclosure with 100 fish (20–30 mm total length). Observations over 24‐h periods showed wide variations of the fish vertical distribution (> 5 m) and two typical aggregation patterns in near‐surface waters at dawn and dusk. No direct relationship was found between light intensity and distribution of the fish during the day. The mean target strength of young whitefish juveniles was found to be – 56 dB when fish were staying near the surface and – 63 dB as they were moving up‐ or downwards.