By Gary B. Kyle
Fisheries Research, Volume 28, Issue 1, August 1996, Pages 29-44, ISSN 0165-7836, DOI: 10.1016/0165-7836(96)00486-9.

Stocking sockeye salmon (Oncorhynchus nerka Walbaum) fry into barren lake systems, which are systems that have an impassable outlet and previously did not have a major population of fish preying on zooplankton, is relatively new in Alaska. The stocking of barren lake systems has resulted in inconsistent responses within the macrozooplankton community, and current fry rearing models derived from systems with established runs of sockeye salmon do not appear to be appropriate for stocking barren lakes. For example, in some of the barren lakes, post-stocking macrozooplankton biomass remained relatively stable whereas in others it decreased by over 100%. Major reasons for the disparity of response to stocking barren lakes include: (1) the inherent low productivity of these lakes; (2) macrozooplankton abundance, composition, and ability to adapt to predation; (3) stocking density; (4) morphometric factors; (5) variability in the indirect effects of predation in individual lakes. The instability of the macrozooplankton community in barren lakes when faced with predation necessitates stocking programs based on a conservative and gradual approach with close evaluation, and experimenting with stocking strategies that ameliorate significant impacts to the macrozooplankton community.
Keywords: Barren lakes; Zooplankton cropping; Sockeye salmon; Hatchery fry stocking; Rearing capacity

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