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Skin Reflectance as a Nonlethal Measure of Smoltification for Juvenile Salmonids
Author(s) -
Haner Philip V.,
Faler Joyce C.,
Schrock Robin M.,
Rondorf Dennis W.,
Maule Alec G.
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<0814:sraanm>2.3.co;2
Subject(s) - smoltification , oncorhynchus , chinook wind , reflectivity , juvenile , fish <actinopterygii> , fishery , biology , gill , rainbow trout , ecology , salmonidae , physics , optics
Our efforts to find nonlethal methods of assessing the parr‐smolt transformation of juvenile steelhead Oncorhynchus mykiss and spring and fall chinook salmon O. tshawytscha led to the development of a video system for quantitatively measuring skin silvering using skin reflectance. Gill Na + , K + ‐ATPase activity, skin guanine concentration, and skin reflectance were recorded from groups of fish marked with freeze brands at hatcheries and downstream sample sites in the Columbia River basin. Skin reflectance of migrants was significantly higher than that of fish before release; nonmigrants (released fish that did not migrate) had significantly lower skin reflectance than migrants from the same groups. Skin reflectance was significantly correlated with gill ATPase activity and skin guanine concentration. Skin reflectance increased during the parr–smolt transformation and could be used as a nonlethal indicator of smoltification.