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Effects of radio‐transmitter antenna length on swimming performance of juvenile rainbow trout
Author(s) -
Murchie K. J.,
Cooke S. J.,
Schreer J. F.
Publication year - 2004
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/j.1600-0633.2004.00061.x
Subject(s) - rainbow trout , fish measurement , antenna (radio) , transmitter , juvenile , fish <actinopterygii> , juvenile fish , biology , fishery , environmental science , ecology , telecommunications , computer science , channel (broadcasting)
– Technological advances have lead to the production of micro radio‐transmitters capable of being implanted in fish as small as c . 5 g. Although the actual tags are small, transmitters are equipped with long antennas that can increase drag and tangle in debris. We examined the effects of radio‐transmitter antenna length on the swimming performance of juvenile rainbow trout, Oncorhynchus mykiss , ( N = 156, mean mass = 34 g, mean fork length = 148 mm). Although we tested a variety of different antenna lengths up to a maximum of 300 mm, only the longest antenna significantly impaired swimming performance relative to control fish ( P < 0.001). There was no difference in swimming performance between the sham (surgery, but no transmitter) and the control fish (handled, but no surgery), suggesting that the surgical procedure itself did not negatively affect the fish. Regression analysis, however, indicated that there was a significant decrease in swimming performance associated with increased antenna length ( R 2 = 0.11, P < 0.001). In addition, when held in laboratory tanks, fish with the three longest antennas (150, 225 and 300 mm) frequently became entangled with the standpipe. We suggest that researchers, under the guidance of the tag manufacturer, trim antennas to the shortest possible length required to detect fish in their specific study area. Antenna length is clearly an important issue for small fish, especially for species that inhabit complex habitats where antennas may become entangled, and where fish must attain speeds near limits of their swimming capacity.