You are here:
SALT MARSH HABITAT FROM A FISH EYE VIEW: A TEST OF THE DIMENSIONLESS INDEX OF HABITAT COMPLEXITY
Citation:
Chintala, M, M Huber, L Meng, AND S Benyi. SALT MARSH HABITAT FROM A FISH EYE VIEW: A TEST OF THE DIMENSIONLESS INDEX OF HABITAT COMPLEXITY. Presented at Southern New England Chapter of the American Fisheries Society, Roger Williams University, Bristol, RI, June 19, 2002.
Description:
Salt marshes are considered important foraging and predator refuge areas for fish, but these functions are rarely measured. The goal of this study was to examine the relationship between the structural complexity of the habitat and fish size in marshes subjected to different watershed land-use and nutrient loads. Previous research has shown that increased land use in the watershed may cause structural changes in the marsh flora. A dimensionless index, DI = (surface area of Spartina alterniflora /surface area of net) x 1000, was used to assess structural habitat complexity. It is predicted that as DI decreases, available space for fish movement will increase, causing an increase in the size of the fish that use the habitat. We sampled nekton in three marshes in RI that experience different levels of land use and nutrient load from the watershed. Sampling was conducted with bottomless lift nets in summer 2001. DI and S. alterniflora biomass increased with increasing land use in the watershed. The relationship between DI and nearest neighbor distance between plants was different at each of the sites. Within each site, the relationship between average fish length and DI were very different. The predicted pattern of DI to open space and DI to fish size was only evident within the site where land use was highest. This suggests that there may be a threshold of S. alterniflora density and size below which the DI is not useful for predicting fish use of these marsh habitats.