Abundance And Diversity Of Fish In Relation To Littoral And Shoreline Features
The effects of small-scale shoreline residential development on littoral fish abundance and species richness was examined at three different scales of observation (within 122, 244, and 488 meters) in Lake Simcoe (Ontario, Canada). A mixed model regression was used to test for effects of development after accounting for seasonal and spatial variation in environmental variables known to affect distribution and abundance of fish. Fish were aggregated near single development structures, such as permanent docks, and repelled from other single structures, such as bank stabilisation. Shoreline developed with multiple features, such as docks combined with break walls, tended to be positively correlated with fish abundance but negatively correlated with species richness. Features such as docks and break walls combined with boathouses were generally associated with a decrease in both abundance and richness. Cluster analysis detected no consistent pattern of association between specific fish assemblages and residential development across the three scales of observation. Increased density and diversity of shoreline residential development tended to be associated with reduced fish abundance and species richness. The specific development features associated with these patterns change with the scale of observation, indicating that fish responded to proximally and distantly located habitat alterations.