Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Journal of fish biology
27 (1985), S. 0
ISSN:
1095-8649
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The efficiency of pike removal from a chalkstream trout fishery, by an angling society using electrofishing, was estimated over five successive autumns using mark-recapture methods. It averaged c. 50% for pike aged 1+ years or more. Numbers of 3+ and older pike decreased from 3.7 ha-1 (1980) to 1.4 ha-1 (1984), but there was no corresponding reduction in recruitment success. Both pike immigration and an inverse relationship between natural and fishing mortality could have reduced the effect of the pike culls. The mean weight of 0+ pike increased from 19.4 g to 48.2 g over the 5 years, but there was no change in the growth rates of older pike. Only the larger pike were able to eat the larger trout stocked, and the reduction in numbers of 3 + and older pike appears to have reduced the predation pressure on the trout population. Angling effort increased more than three-fold over the 5 years studied and rod-catches more than doubled, but catch-per-unit-effort was extremely variable between years. The increased rod catch occurred despite the decrease in numbers of large (〉 33 cm) trout stocked in the spring and early summer. Compared with pre-cull years, the angling society saved about ş850 (present day prices) by stocking fewer trout.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1095-8649.1985.tb03244.x
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