| Creating or enhancing recreational fisheries through sport-fish stocking is an accepted practice, but can also have negative consequences on the recipient ecosystem. I studied 11 boreal foothills lakes, 5 with and 6 without stocked trout. All lakes supported native forage fish and 3 amphibian species: wood frog (Lithobates sylvaticus), boreal chorus frog (Pseudacris maculata), and western toad (Anaxyrus boreas). To assess effects of stocking on amphibian populations, I examined the relative abundance and size of adults and young-of year, and timing of metamorphosis over 3 years. For wood frogs and western toads, none of these parameters differed significantly between stocked and unstocked lakes. However, adult boreal chorus frogs were significantly more abundant on unstocked lakes. Wood frog abundance and size differed between 11 fish-bearing lakes and a fishless lake, suggesting fish presence, per se, affects frog populations. I conclude that generally, stocked trout are not affecting amphibian populations in Alberta's boreal foothills. |
