Research Document - 2002/075
A perspective on the use of Performance Based Standards to assist in fish habitat management on the seafloor near salmon net pen operations in British Columbia
By C.D. Levings, J.M. Helfield, D.J. Stucchi, T.F. Sutherland
Abstract
In this document we consider scientific techniques and parameters for measuring changes to the marine ecosystem related to finfish aquaculture in British Columbia, focusing on salmon net pen operations. Our review is limited to seafloor habitats and draws in information from the peer reviewed literature and unpublished data as appropriate. We found an almost complete absence of peer reviewed (journal) papers in the literature from B.C. As we do not support the idea of extrapolation of the extensive published data from other parts of the world to Pacific Region without local verification, our response to specific questions from habitat managers was conditioned by the lack of research publications.
The Performance Based Standards (PBS) approach is a management technique that is used by numerous engineering and education organizations and by a few environmental agencies. The approach is effective with the following conditions: 1) the problem has a narrow focus; 2) response to a system change is well understood by science; 3) when an effect is reversible; and 4) when there is a management response to a threshold or "trigger". Because the responses of seafloor ecosystems to organic waste from fish farms are poorly documented in B.C., we could not find scientific information on the use of PBS to conserve the productive capacity of their component fish habitats. One of the topical PBS methods recommended for evaluating habitat effects of salmon net pen rearing is based on sulfide-organism relationships in muddy sediments. Based on the field correlation data available in the scientific literature, there is a technical basis for these PBS in the particular ecosystems where they have been developed. There are limitations for applying them in B.C.; methods must be developed, which allows them to be used on a variety of habitat types and with an improved mapping scheme. Reversibility is also poorly documented. In our view, PBS are not effective for integrated coastal management, which is the long term direction that DFO scientists have recommended for the DFO's Pacific Region - hereafter referred to as the Region. The choice of parameters and thresholds to indicate that an important ecological change has occurred from salmon net pens is dependent on the objectives that managers have selected, or the particular policies they are dealing with for a particular habitat or ecosystem. The objectives and policies will determine the scale at which effects are assessed - however for fish habitat management, we suggest the "lease scale". We suggest a number of biological and physico-chemical variables as threshold criteria or triggers that could be used if research information from B.C. were available on them. As a first principle, we would not recommend that a single number for any parameter be used as a threshold value. As data are provided from research and monitoring projects related to fish farming in B.C., we suggest that a scientific workshop be convened to discuss the results already available, variables used, and provide guidance for improvement where needed. The recommendations from this workshop should be subjected to the peer review process used by scientific journals.
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