Science review of two proposed Trout aquaculture sites in Bay d’Espoir on the South Coast of Newfoundland

Abstract

Nova Fish Farms Incorporated has submitted applications to the Province of Newfoundland and Labrador to develop and operate two new Rainbow Trout (Oncorhynchus mykiss) aquaculture sites at Cape Mark and Collins Head in Bay d’ Espoir, located on the south coast of Newfoundland. Estimates of benthic-Predicted Exposure Zone (PEZ) for both feed waste and feces at each site extend beyond the lease areas, although there is no predicted overlap expected between the two proposed sites. Feed waste and feces can potentially contain bound substances such as medications, if used. Geodiidae sponges and the Northern Cerianthid anemone, both vulnerable marine ecosystem (VME) indicators, were identified within the Collins Head lease area, but these taxonomic identifications are uncertain. No species listed under schedule 1 of Species at Risk Act (SARA) were reported at either of the sites. There are no Ecologically and Biologically Significant Areas (EBSA) that overlap with any portion of the benthic-PEZs or pelagic-PEZs or the lease area for either site. The pelagic-PEZ, predicting the spatial extent across which exposure to a registered pesticide may have an adverse effect, illustrated some overlap between the proposed sites and potential impact to the shoreline adjacent to each site. Shrimp and krill species were observed at both sites. For krill species occupying the pelagic zone, and some species of shrimp using it intermittently, the exposure to bath pesticides, although rarely used, could cause adverse effects. Although escapes from trout aquaculture farms remain possible, reported trout escape events in NL have been few and of low numbers since 2012. Escapees would primarily be expected to disperse to rivers within the proposed South NL-West Designatable Unit (DU) for wild Atlantic Salmon, where significant declines in abundance have occurred. Escapees may also disperse to a portion of rivers in the South NL-East DU. Interbreeding between escaped Rainbow Trout and wild Atlantic Salmon is not expected to occur. However, interactions between them may still result in ecological or indirect genetic impacts on wild Atlantic Salmon populations. While there have been no reports of entanglement of listed Species at Risk in finfish aquaculture gear in the DFO Newfoundland and Labrador Region, aquaculture infrastructure increases the potential for entanglement for some listed Species at Risk.