Passage of Gizzard Shad and Threadfin Shad Larvae through a Larval Fish Net with 500-μm Openings

Autor: David A. Tomljanovich, John H. Heuer
Rok vydání: 1986
Předmět:
Zdroj: North American Journal of Fisheries Management. 6:256-259
ISSN: 1548-8675
0275-5947
DOI: 10.1577/1548-8659(1986)6<256:pogsat>2.0.co;2
Popis: Accuracy of larval fish entrainment estimates at power plants depends on the effectiveness of sampling gear. Simulated tows in a laboratory flume were made to evaluate retention of gizzard shad (Dorosoma cepedianum) and threadfin shad (Dorosoma petenense) larvae in a larval fish net with 500-μm square mesh openings that is regularly used by the Tennessee Valley Authority and other investigators. Retention of 1-d-old gizzard and threadfin shad larvae (3.0-5.0 mm total length) averaged less than 15%. Average retention was 32% over all tests with tow velocity, tow duration, species, and age as variables. Retention was significantly greater at a tow speed of 1.0 m/s than at a speed of 0.5 m/s. No effect of tow duration on retention was observed. Tests conducted in static water revealed about 40% of 1- and 3-d-old threadfin shad swam through the 500-μm openings during a 5-min period and about 10% were extruded through the net when it was washed down. These results suggested that (1) the use of larval ...
Databáze: OpenAIRE
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