Reproductive Ecology of Northern Fishes
The sustainability of wild fish populations is dependent upon successful reproduction and recruitment. Understanding how the reproductive success of fish populations respond to changing environmental conditions is a central issue in fisheries science. It has long been recognized that gamete quantity (expressed as gonad mass in both sexes, or as fecundity in females) can vary considerably among fish populations as well as among individuals within populations. In general, larger and older individuals will produce more gametes. More recent research has indicated that larger and older individuals may also produce higher quality gametes, and hence offspring. The implication of this finding is that the size or age-class structure of spawning stocks may influence their reproductive success. This program is designed to quantify variability in reproductive effort among individual spawners, determine how this variability is linked to parental and environmental characteristics, determine how reproductive effort may be altered by anthropogenic stressors, and examine the implications for reproductive success. The results will allow a clearer assessment of how fish reproduction may be influenced by environmental change and by fisheries management practices. Two recent projects are examining: i) reproductive ecology of a mid-winter spawner, the burbot, across a latitudinal gradient; and ii) temporal changes in the reproductive investment of Lake Nipissing walleye following food web disruption.
A Burbot in Chitty Lake, NWT July 2009.