Definition of precautionary approach reference points for Atlantic salmon, DFO Gulf Region

Abstract

Upper Stock Reference (USR), Target Reference (TR) and Removal Rate (RR) reference points are defined for 98 Atlantic Salmon rivers in DFO Gulf Region. The abundance reference points are defined in units of eggs from all anadromous age and size groups. The USR and TR values are defined using the ratio of these reference points to the Limit Reference Point (LRP) from an analysis of adult to adult stock and recruitment data. The ratios quantify the spread between the LRP and corresponding USR and TR, of 3.8 and 4.7, respectively. These ratios are applied to the previously defined LRP values based on the egg to salmon smolt freshwater phase to quantify the river-specific USR and TR points. The removal rate equivalent to fishing at maximum sustained yield (MSY) when the recruitment is at MSY defines the RR reference for all the rivers, a mean value of 0.6. Candidate harvest decision rules (HDR) for the recreational Atlantic Salmon fishery after the constitutionally recognized right of first access to natural resources for the Indigenous peoples is respected, are evaluated for compliance to the Precautionary Approach (PA) policy. The candidate HDRs reviewed, using the Miramichi River as a case study, have several elements that conform to the PA policy and guidance for harvest strategies while other elements do not conform to the PA. The candidate HDRs would allow a directed catch and release recreational fishery when the abundance is in the critical zone, as low as 15% of the LRP. Although the losses from a catch and release fishery may potentially represent a small percentage of the total eggs, 1% to 7% depending upon the exploitation rate and post-release mortality assumptions, any loss due to directed fishing in the critical zone could be interpreted as not conforming to policy of lowest level possible and preventable decline. Our ability to develop and implement robust HDRs is limited due to the lack of a full evaluation of the performance of candidate HDRs, that includes forecast models and the effect of management measures on removal rates.