Microhabitat analysis (n = 9 sites) indicated grass pickerel were always associated with either aquatic macrophytes (77%) or logs/woody debris (23%).
Because all sites (n = 125) evaluated contained grass pickerel, we examined the relationships between IBI and QHEI, and grass pickerel catch and QHEI to determine whether habitat factors were structuring the fish community and the catch of grass pickerel.
Values for all these factors, except temperature were significantly related to grass pickerel catch, but the relationships were biologically weak, with the possible exception of average stream width (Table 4).
Habitat factors have not been extensively evaluated for grass pickerel with studies limited to areas in Wisconsin, Okalahoma and Canada (Klienert and Mraz 1968; Ming, 1968; Foster, 1980).
Our findings in Indiana suggest grass pickerel may occur in communities of varying quality as measured by the Index of Biotic Integrity and the Qualitative Habitat Evaluation Index (QHEI).
Grass pickerel are lie-in-wait predators (Moyle and Cech, Jr., 2004) that are not adapted to fast moving water.
The range of water quality factors measured in Indiana showed grass pickerel were able to adapt and survive in a diversity of warm water habitats, including sites with very high temperatures (>32 C) and low dissolved oxygen (<1.0 mg/1; consistent with Scott and Crossman, 1973).
The QHEI was not a good tool to assess general habitat parameters relating to grass pickerel presence.
Habitat use of grass pickerel in Indiana was based on two main components: in-stream cover and slow moving water, which are similar for other esocids (Pflieger, 1997) with one exception.
Observations of the natural history of the chain pickerel (Esox niger).
The grass pickerel (Esox americanus vermiculatus) Le Sueur in Canada.
Factors influencing the predator-prey relations of a small esocid, the grass pickerel, (Esox americanus vermiculatus).
The life history of the grass pickerel (Esox americanus vermiculatus) in southeastern Wisconsin.
Life history of the grass pickerel, Esox americanus vermiculatus, In: Oklahoma.
The summer food and habits of the chain pickerel Esox niger of a small New York pond.