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Comparison of Four Trawls for Sampling Juvenile Shad
Author(s) -
Michaletz Paul,
Boxrucker Jeff,
Hale Scott,
Jackson James R.
Publication year - 1995
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1995)015<0918:coftfs>2.3.co;2
Subject(s) - dorosoma , gizzard shad , fishery , transect , environmental science , biology , ecology , fish <actinopterygii>
A single‐mesh neuston net, bimesh neuston net, paired frame trawls, and Tucker trawl were compared at three sites in Lake Texoma, Texas‐Oklahoma, to determine their relative efficiency and precision in sampling juvenile threadfin shad Dorosoma petenense and gizzard shad D. cepedianum . The frame and Tucker trawls provided similar estimates of threadfin shad and gizzard shad densities that were significantly higher than those estimated for the two neuston nets. The bimesh neuston net provided significantly higher estimates of threadfin shad and gizzard shad density than the single‐mesh neuston net. Correlation of density estimates of threadfin shad and gizzard shad among transects were highest for the frame and Tucker trawls, indicating that these gears provided the most similar trends in density estimates among transects. Similarly, the frame and Tucker trawls provided the most similar estimates of threadfin shad and gizzard shad size distributions. The Tucker trawl captured significantly higher proportions of larger threadfin shad than the frame trawls, but differences in mean lengths between the trawls were small (0–0.8 cm). Overall, the frame and Tucker trawls were most effective for collecting juvenile shad. A moderate level of precision (median ±20%, ∝ = 0.20) of threadfin shad density estimates could be obtained with 6–33 hauls per site with the frame trawls or 15–67 hauls per site with the Tucker trawl. More sampling effort was required (83–111 hauls with frame trawls and 101–214 hauls with the Tucker trawl) for estimates of gizzard shad density, presumably because fish density was low and inconsistent (0–12 fish/1,000 m 3 ).