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Use of a Remotely Operated Vehicle to Study Habitat and Population Density of Juvenile Lake Trout
Author(s) -
Davis C. L.,
Carl L. M.,
Evans D. O.
Publication year - 1997
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1997)126<0871:uoarov>2.3.co;2
Subject(s) - salvelinus , fishery , remotely operated vehicle , remotely operated underwater vehicle , trout , netting , environmental science , juvenile , juvenile fish , population , oceanography , fish <actinopterygii> , biology , ecology , geology , demography , artificial intelligence , sociology , computer science , political science , robot , law , mobile robot
We determined the feasibility of using a remotely operated vehicle (ROV) to observe juvenile lake trout Salvelinus namaycush . The ROV was equipped with a high‐resolution, low‐light, black‐and‐white video camera and two halogen headlamps and was tethered by a 152‐m umbilical cable. We used the ROV to sample two central Ontario lakes: Source Lake in summer and fall and Lake Opeongo in summer. We surveyed the lake bottom at depths of 2.5–40 m in both lakes during day and night. The ROV traveled slightly above the substrate recording a field of view 1.8 m wide and 0.3–0.5 m high at a distance of 1.8 m in front of the ROV. Overall, 54,594 m 2 of lake bottom were sampled, and 114 juvenile lake trout (<300 mm, total length) were observed. Juvenile lake trout exhibited minimal avoidance of the ROV with some individuals being observed for several minutes (mean, 41.6 s). The observed distribution suggested movement to shallower habitat at night. Mean (±SE) lake trout densities varied between the study lakes for depths of 5–25 m (Opeongo: 5.2 ± 2.0 fish/ha; Source: 25.9 ± 6.5 fish/ha), which was consistent with catch per unit effort in small‐mesh gill nets for these lakes (Opeongo: 0.9 ± 0.1 fish/net‐night; Source: 5.8 ± 0.4 fish/net‐night). The ROV allowed nonlethal sampling and direct estimation of fish density, thereby offering a good alternative to conventional netting techniques.