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Growth, Survival, and Vulnerability to Angling of Three Wild Brook Trout Strains Exposed to Different Levels of Angler Exploitation
Author(s) -
Nuhfer Andrew J.,
Alexander Gaylord R.
Publication year - 1994
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(1994)014<0423:gsavta>2.3.co;2
Subject(s) - trout , salvelinus , biology , fishing , fontinalis , fishery , population , ecology , fish <actinopterygii> , demography , sociology
It has been suggested that the genetic growth potential of trout may be degraded over time by differential angler harvest of the faster‐growing fish of each cohort. To test this hypothesis, young‐of‐the‐year wild brook trout Salvelinus fontinalis from two branches of the Au Sable River and from the East Branch of the Fox River were stocked in three experimental Michigan lakes to determine their relative 2‐year growth and survival. Brook trout populations from the Au Sable River are believed to have been exploited more intensively than the population from the East Branch of the Fox River. We found that brook trout from the East Branch Fox River grew significantly faster than fish from either the North Branch or the mainstream Au Sable River. The superior growth of East Branch Fox River brook trout was most evident in Hemlock Lake, where all strains grew best. Mature males were significantly longer and heavier than mature females when data were pooled across strains for each lake, East Branch Fox River mature females allocated relatively less energy to gonadal tissue than mature females of the Au Sable River strains. There were no significant differences in survival between the three brook trout stocks tested. A significantly higher percentage of the population of faster‐growing East Branch Fox strain brook trout were caught from North Twin Lake by experimental angling than of either of the Au Sable River strains. The results of this study suggest that the intensity of angler exploitation, over time, may have altered the genetic potential for growth and catchability of these wild brook trout strains. It is also possible that founder stocks were genetically dissimilar or that genetic divergence resulted from differences in natural selection pressures between the study rivers. Although it could not be determined from this study why the growth and catch rates varied among the wild stocks tested, the documented differences provide information on stock performance that can be used by fisheries managers.