PW18 Field Biological Monitoring of Ecosystem Impairment
Exhibit Hall
8:00 AM - Wednesday
(PW283) Investigating reduced reproductive performance in fish populations in potato growing areas of New Brunswick, Canada.
Brasfield, S1, McMaster, M2, Munkittrick, K1, 1 University of New Brunswick, Saint John, New Brunswick, Canada2 National Water Research Institute, Burlington, Ontario, Canada
ABSTRACT- Previous research has demonstrated that fish in agricultural areas in New Brunswick have reduced proportions of YOY fish, due to either reproductive dysfunction, increased mortality, or a combination of these factors. The main objective of the study was to identify the potential mechanisms associated with the reduced reproductive performance in potato growing areas of New Brunswick, Canada. Normal reproductive profiles, growth and mortality were assessed for reference populations of slimy sculpin (Cottus cognatus) to identify the most appropriate window to assess reproductive integrity. This study has ruled out a seasonal or ecological basis for the depressions that have been previously documented at agricultural sites. Over three growing seasons fish densities and size structures have been monitored non-lethally along an agricultural gradient to identify peak mortality periods across all size classes. Data indicate that the peak risk period may occur in late summer, with chemical application coinciding with increased thunderstorm activity, rather than overwinter or after spawning mortality. Year class failures have been documented, and subsequent recoveries have been monitored over the past three years. This information was collected on slimy sculpin, a benthic, spring spawning species, but additional comparisons included brook trout (Salvelinus fontinalis), a pelagic, fall spawning species in agricultural areas to determine the differential susceptibility relative to reproductive timing. Integrating the knowledge developed on episodic mortality, reproductive development and reproductive performance has allowed for more complete assessment of impacts related to agriculture.
Key words: fish populations, agriculture, effects based assessment, reproduction