Tyler Winter

Advanced comp

3/31/05

Figures and Graphs for Proposal

Fig. 1. Biomass of Coregonids in Lake Superior estimated from near shore bottom trawls, (A) Lake Herring (B) Bloater and (C) Kiyi. (is U.S. waters and is for Canadian waters, also note differences in scale between graphs) Bloater biomass not estimated prior to 1989.

Bloater, kiyi, and lake herring constitute the majority of Lake Superior’s forage base. These fish also comprised a significant commercial fishery, but in recent years the planktivores community has become unstable. It is our intention to investigate the competitive interactions between these species to determine what effect they are having on each other, and to better understand fluctuations in their populations.

Fig. 2. From right to left: herring, bloater and kiyi; notice the size of the eye relative to the length of the head.

Coregonus artedii, C. Hoyi and C. Kiyi are all closely related species but they have important morphological differences that offer clues to their different habits. Kiyi have the largest eyes and the longest fins, they also live in deeper water than the other two. Bloaters are especially similar to lake herring but have longer fins and have a more keel like stomach. Lake herring are the largest of the three and the most abundant.

Fig. 3. The current and historical rang of C. Kiyi.

Kiyi are a threatened species once abundant throughout the great lakes. Today kiyi are only found in portions of Lake Superior. Because their range is restricted to one lake they are susceptible to environmental change, exploitation, and invasive species.

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