Understory Kelp Salvage, Recolonization Of Disturbed Sites To Mitigate Temporal Habitat Loss.
Defense Construction Canada, on behalf of the Department of National Defense (DND), undertook dredging in Constance Cove, Esquimalt Harbour, as part of DND’s multi-year, harbour-wide sediment remediation program. One of the mitigation measures recently implemented with the Constance Cove remedial dredging is the salvage of understory kelp within the project’s dredge footprint prior to the dredging; the relocation of salvaged material to a temporary storage area, and restocking once construction is complete. This work has been conducted on an ongoing basis since 2017 by Archipelago in collaboration with SNC Lavalin and SLR Consulting. These kelp salvage measures are intended to address impacts of temporal fish habitat loss due to dredging activities in an area with an existing kelp bed, and to reduce the succession time required for a disturbed area to return to a functioning kelp habitat. Understory kelp provides important functions supporting the productivity of local Esquimalt Harbour Commercial, Recreational and Aboriginal (CRA) fish such as Pacific herring, rockfish, Pacific salmon, greenling, sea perch, among others. The understory macro algae Saccharina latissima (sugar kelp) was the primary target species for salvage in areas within the dredge footprint that had greater than 25% cover attached to salvageable rock substrate. During storage of salvaged kelp and substrate, kelp enhancement lines, employing locally developed kelp cultivation techniques, were installed to provide an additional source of spores to inoculate the salvaged substrate, as well as provide additional temporary fish habitat during construction activities.