Amendments to the federal Pulp and Paper Effluent Regulations in effect since 1992, require mills in Canada discharging effluent to an aquatic receiving environment to conduct an Environmental Effects Monitoring (EEM) Program to determine whether existing regulations adequately protect fish, fish habitat and use of fisheries resources. As one component of the EEM, mills measure indices of growth, survival and reproduction in wild-caught fish exposed to effluent and compare them with fish not exposed to effluent. A review of the first round of Fish Surveys (Cycle 1: 1993-1996) indicated that they contributed useful data in the freshwater receiving environments for which they had been designed, but performed poorly in the more complex marine and estuarine environments. The most prevalent and serious problems were that insufficient fish were caught and the degree of exposure to effluent could not be quantified. Recommendations to address these problems in Cycle 2 (1997-2000) included selection of small-bodied, presumably more sedentary, fish and studies on the alternative approaches: caged bivalves and onshore bioassays (mesocosms). Difficulties encountered in Cycle 1 studies which could not be resolved became reasons to exclude the Fish Survey from 12 of 28 marine EEM studies in Cycle 2. Six marine mills completed the standard Fish Survey with finfish. Three of these used small-bodied fish successfully, though further information will be required on their range of movement and technical guidance on appropriate sampling. Six studies examined wild bivalves or snails in place of one or both finfish sentinels. None of the invertebrate studies provided all of the information required by the Fish Survey, with only two studies providing age information required to assess growth, only one study reporting gender, and none of the studies reporting measures of reproduction. Six mills conducted or participated in developing alternative approaches for fish surveys: two caged bivalve studies, three mesocosm studies using fish, and one onshore bioassay using bivalves. While providing no direct measurements of effects on reproduction these tools evaluated potential impacts of effluent on survival and growth and supplied information helpful for subsequent investigations of the causes of effects observed in wild fish.
Many environmental studies generate multivariate data, often consisting of two or more conceptually different sets of variables. For example one may wish to relate species abundances to environmental variables. A recent concept gaining popularity in marine benthic impact studies is the "sediment quality triad", which relates benthic community composition as one set of variables to sediment chemistry (contaminents) as a second set, and to toxicities of sediment to test organisms in the laboratory as a third set. This is conceptually appealing, but the original applications of the concept rely heavily on indices (e.g. diversity indices, toxicity indices) rather than on multivariate statistics. Procedures for testing and describing relationships among variables are reviewed, with emphasis on environmental applications. We describe and exemplify several multivariate statistical approaches to effective application of the sediment quality triad concept, including Mantel's tests and related descriptive analyses; ordination on each set of variables followed by methods to relate ordination axes among the sets; canonical correlation analysis; fitting a general linear model; and cluster analysis on each set of variables followed by a three-way contingency table analysis.
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