Secondary Production of Tiger Salamanders (Ambystoma tigrinum) in Three North Dakota Prairie Lakes

Abstract

In three prairie lakes studied in 1981-82, larval tiger salamander (Ambystoma tigrinum) densities reached highs of 5000 .cntdot. ha-1, maximum biomass (wet eight) was 180 kg .cntdot. ha-1, and maximum annual production was 565 kg .cntdot. ha-1. Within a given lake, overwinter survival of larvae varied markedly from year to year. Overwinter survival of larvae was excellent in Lake II; in spring 1981, densities were 800-1000 .cntdot. ha-1. In 1982, no larvae overwintered in Lake II, and none overwintered in Lake I in either 1981 or 1982. In May 1981, larvae were large (mean weight of 150 g) and their biomass of 150 kg .cntdot. ha-1 was nearly as large as the maximum biomass of 160 kg .cntdot. ha-1 in late July of larvae from the year''s cohort. This was in contrast with 1982 in Lake II and with both 1981 and 1982 in Lake I when there was an extremely low biomass in the spring, composed of many small larvae. The large larvae that overwintered in Lake II in 1981 did not prey on young-of-the-year larvae; their high densities may have actually reduced invertebrate predation on salamander larvae; in July, larval salamander densities of 5000 .cntdot. ha-1 were the highest measured.