Influence of the reproductive strategies of fishes on study designs for environmental monitoring programs

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University of New Brunswick
Federally regulated environmental effects monitoring (EEM) programs have been implemented for pulp and paper and metal mining effluents in Canada. With the recent development of large pulp mills in Chile, Brazil, and Uruguay, there has been increased attention on developing EEM programs in these areas. Unlike the EEM program in Sweden, which regulates species selection and timing of sampling, there have been no such restrictions in Canada, resulting in the use of more than 65 species for EEM programs. The objective of this research is to study the reproductive biology of fish species to improve EEM study designs to assess reproductive impairment in fishes. Optimal sampling periods to detect reproductive impacts for species used in Canada's EEM program were determined based on the reproductive strategies of the sentinel species. It was determined that 72% of EEM studies using small-bodied fish species were conducted outside of the reproductive period of the sentinel species, limiting the usefulness of the reproductive assessment. Seasonal studies on changes in gonad size, liver size, and condition in seven small-bodied fishes were conducted to gain further insight into the biology of these species. Methods to predict the reproductive strategies of fish species were tested by studying prespawning gonad weight: body weight relationships and oocyte size and development stage in species in Atlantic Canada. In South America, basic life history characteristics for many species are unknown, but are necessary to consider when designing an effective EEM study. A review of basic life history information of several abundant fish species was conducted to assist in the development of an EEM program for a pulp mill on the Uruguay River. Gonad size relationships and histological analyses of ovaries of abundant species on the Uruguay River were studied to identify an optimal species to use as a sentinel for assessing reproductive impairment in fishes.