Research Document 2020/026
A Regional Assessment of Ecological Attributes in Rockfish Conservation Areas in British Columbia
By Dunham, J.S., Yu, F., Haggarty, D., Deleys, N., Yamanaka, L.
We conducted a regional assessment of four ecological attributes (size, rockfish habitat, depth, and connectivity) in 164 Rockfish Conservation Areas (RCAs) in British Columbia. The purpose of this research was to evaluate how effective RCAs are at achieving their conservation objective, which is to protect portions of inshore rockfish populations and their habitat from fishing pressure. Analyses were conducted using GIS information and existing habitat models. Attribute thresholds were derived from the literature. We took three approaches to our analyses. RCAs were scored based on:
- individual attributes,
- attributes summed together to form a single index of overall status, and
- ideal attribute criteria to assess how the current network compares to a best case scenario.
Generally RCAs were ranked by lowest score/poorest performer to help prioritize RCAs for further evaluation to determine whether a strategic change (boundary adjustment, relocation) might improve their conservation value to rockfish.
Although inshore rockfish have small home ranges, some RCAs might be too small resulting in excessive spillover of mature fish. Available model-based data indicate some RCAs contain very little rockfish habitat and, therefore, may not support high abundances of fish which would limit population rebuilding efforts. RCAs generally protect more shallow (<50 m) areas preferred by Black, Copper, and China Rockfishes and not deeper areas (>100 m) utilized by other species like Quillback and Yelloweye Rockfishes. The network is well connected at distances of 100 km; at distances of 50 km several gaps exist in Haida Gwaii, the central coast, along the west coast of Vancouver Island, and in three inlets (Bute, Holberg, Jervis). RCAs in the Northern Shelf Bioregion (NSB) generally scored higher suggesting these RCAs might be providing greater protection to rockfish. Eight point five percent (14) of RCAs currently meet the ideal criteria for attributes, and an additional 43% (70) meet at least five of seven criteria and, therefore, may be good candidates for improvement. Considerable rockfish habitat exists in other types of protected areas outside the RCA network, especially in federal protected areas such as Marine Protected Areas, National Marine Conservation Areas, and Marine National Wildlife Areas where there is some protection afforded to rockfish and their habitat. Rockfish habitat is also prevalent in provincial conservancies, although no long-term protection for rockfish currently exists in provincial protected areas.
RCAs with the lowest attribute scores should be evaluated further to determine how to improve their conservation benefit to rockfish. First, existing surveys and data can be used to test the efficacy of our ranking system. Second, ecological monitoring and improved compliance should be considered before implementing boundary changes or relocating RCAs. Third, conservation benefits to rockfish might be increased in RCAs if their boundaries are adjusted and configurations changed to increase their sizes, incorporate more habitat over a broader range of depths, and encompass entire habitat areas to limit spillover of mature fish. Those RCAs where there is very little habitat inside and nearby could be moved to better locations.
Recommendations and knowledge gaps are listed. A long-term recommendation is most RCAs should be ground-truthed using non-destructive sampling methods to verify conclusions in this report and the presence of essential habitat and rockfish. Results from this research will help inform consultations with First Nations and stakeholders regarding potential changes to existing RCAs.
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