Assessment of Potential Indicator Species for Monitoring ...

ioaccumulation of chemical contaminants at this trophic level. For the purpose of this
report the study area included all rivers, lakes and water systems draining into the Fraser
River upstream of the confluence with the Pitt River (Map 2.1).
2.2 Selection Criteria
Criteria used in this study were adapted from Hebert et al. (1993) with modifications
specific to the aquatic ecosystem of the Fraser River Basin. An attempt was made to
develop an objective set of criteria based on the availability of published information on
each species, and the feasibility of sample collection. Criteria were not designed to be
sensitive to details such as variations in sample size, and/or sensitivity of individual
species to specific contaminants. In addition, care was taken to objectively judge each
species without discrimination or influence based on any kind of associations. For
example, a potential indicator species could be endangered, or possibly revered and
protected for symbolic reasons (e.g. the Bald Eagle). It may also be of economic
importance and necessary for the livelihood of indigenous people.
Selection criteria were divided into five categories: 1) fundamental ecological
attributes; 2) understanding and documentation of ecology; 3) ease of sample collection;
4) suitability for laboratory study; and 5) knowledge pertaining to other contaminant
research. How well a species fulfilled each category’s requirements was quantified by
systematically answering its constituent questions and arriving at a numerical score. A
high final score implied that the species in question would be valuable as an indicator of
pollution for the aquatic ecosystem of the Fraser River Basin.
Criterion 1 pertains to the most basic ecological attributes inherent to a species.
Criteria 2 - 5 are an indication of the amount of research and documentation that exists for
a species. As scores in these criteria are based on available information, once missing
data is identified, it is quite possible that another in-depth literature search, or a
subsequent study may be all that is necessary to improve on a score. Each criterion
category is presented along with comments on its relevance, and a short explanation for
the score given. While most questions were answered as either yes (1) or no (0), some
required a more subjective answer within a range of possible scores. If information was
insufficient to judge, the species scored zero by default. In many instances there was no
easy yes or no answer. For each species, a synopsis of the information used to arrive at
a score is provided in Appendices 1 - 3.
Criterion 1 - Fundamental Ecological Attributes
1a Is the species a year-round resident of the Fraser Basin?
Species which reside year-round within the Fraser Basin are preferable to
migratory species which may return to the basin following exposure to
contaminants elsewhere. Resident species were scored as one.
2