Variability in early development and growth of Great Lakes burbot: developmental patterns in cultured and wild-caught larval burbot.

Abstract

Throughout the Great Lakes, burbot Lota lota are a native, high-trophic level predator that plays a substantial ecological role. L. lota spawning occurs during wintertime and early spring with length-at-hatch of 3 mm. Wild-caught larval L. lota were obtained from three different locations: Lake Superior Keweenaw Peninsula, Ontonagon, Michigan (LSKP), Lake Michigan Midlake Reef (LMMR) and the St. Clair-Detroit River System (SCDR). Adult spawning L. lota were captured from the Sturgeon River, Pelkie, Michigan (LSSR) and were artificially fertilized; eggs were retained and reared in a laboratory setting. Throughout the first 10 weeks of development, cultured larval L .lota were randomly selected and photographed to measure morphological features. These features were contrasted between cultured larvae and wild-caught larvae to understand developmental variability in L. lota. From patterns discerned in both cultured and wild-caught larval L. lota we demonstrated the importance of asynchronous hatching, source location, and variability in larval L. lota development. Comparisons of wild-caught larval L. lota showed morphological differences, as well as variability in stage and size based on sampling month. These results established that larval L. lota development in the Great Lakes is highly flexible and both species-specific and environmental processes create the observed variability. The impact of this variability on L. lota populations must be explored to further understand this native Great Lakes species.