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This document presents the data and methods used to assess the stock status of the northern contingent of Atlantic mackerel (Scomber scombrus) in the Northwest Atlantic. The presented and reviewed stock status indicators (February 20-22, 2023) were estimated with an agestructured stock assessment model that was fitted to landings data, landings-at-age and an egg survey index. The estimated 2022 spawning stock biomass (SSB) was at 42% of the Limit Reference Point, defined as 40% of SSB40%, placing the stock in the Critical zone of the Precautionary Approach Framework. The stock has been in or near the Critical zone since 2011. Recent average recruitment (2012-2022) has been low relative to the previous period (1969-2011) and the age structure of the stock remained truncated. Short-term projections indicated that the probability of the SSB leaving the Critical zone by 2025 varied around 37.5% for a total allowable catch (TAC) of 0 t and around 16% for a TAC of 8,000 t, given continued U.S. fishing and recreational fishing in Canada. [ABSTRACT FROM AUTHOR]

Canada's Fisheries Act was revised in 2019 to include new Fish Stocks provisions. Updated science guidelines to support the Sustainable Fisheries Framework policies, in particular the Fishery Decision-Making Framework Incorporating the Precautionary Approach (PA Policy), and legal and regulatory requirements are also under development. To inform the development of science guidelines, we reviewed the technical specifications of reference points and harvest control rules for a subset of key harvested stocks, focusing primarily on those domestically managed and subject to the PA Policy. The adoption of default guidance values of the limit reference point (LRP) and upper stock reference (USR) provided in the PA Policy (0.4 and 0.8 BMSY) is not required, but these values appear to have been widely embraced (43% and 65% of cases, respectively). The USR by definition serves a number of functions, including an operational control point (trigger for management action) to control the risk of approaching the LRP, Healthy-Cautious zone boundary, and target. Science guidelines can provide support for identifying alternative USRs by noting proxies for BMSY (enabling use of proxies for 0.8 BMSY) and by addressing various functions attributed to the USR separately. Removal References (RRs), like USRs, may serve multiple purposes across the stocks in this review. We found that RR values are consistent with indicating whether harvests are at "approved [target] levels" in a wide range of stocks, and sometimes with limits to be either avoided or with which to characterize acceptable stock status in terms of overfishing on the fishing mortality (F)-axis of the PA Policy. Science guidelines could provide support for identifying RRs by highlighting FMSY proxies and characterization of stock states on the F-axis. Four broad types of harvest control rules (HCRs) appear to be implemented in Canada: feedback status-based rules, mixed feedback/feed-forward risk-based rules, "constant" rules with no operational control points and feedforward-only objective-based "rules." The provisional HCR suggested in the PA Policy guidance is not often used although three-part rules with control points at the LRP and USR are common (38% of HCRs). Rules varied widely, although the vast majority are targeted toward informing quantitative output controls (catch limits). To support the new provisions, the development of updated science guidelines should aim to support easier identification of PA components and more consistent use of terminology for key aspects of the PA Policy, including reference points, operational control points for HCRs, and measurable objectives. The HCR types and other measures will vary widely for fisheries that represent a spectrum of data and assessment model availability for key harvested stocks. As science support may be requested for developing and evaluating a wide range of HCRs, science guidelines will need to address both prospective and retrospective evaluation for an array of possible rules that reflect input and output controls and interact with other management measures. [ABSTRACT FROM AUTHOR]

Rebuilding plans are required by law under the new Fish Stocks provisions of the revised Fisheries Act for major fish stocks prescribed under regulations that have declined to, or below, their limit reference point. The provisions state that the biology of the fish and environmental conditions facing the stock will be taken into consideration in the design of rebuilding strategies. Rebuilding strategies inform the development of rebuilding plans and should be regarded as integral to overall management (harvest) strategies. Science activities focus on the development and evaluation of management strategies in response to stated objectives, including rebuilding. Viewing a rebuilding strategy as separate from the overall management strategy can lead to the deferral of actions intended to prevent stock decline. Failure to plan rebuilding measures before they are needed can create hard-to-resolve conflicts with measures intended to provide opportunities for resource use. Increased likelihood that rebuilding is achieved depends on planning the transition from rebuilding to target outcomes within a management strategy. Like many other jurisdictions, Canada advocates management by reference points. Our review of international fisheries agreements highlights key elements that produced Canadian fisheries policy related to the Precautionary Approach. Interpretation of policy must distinguish between objectives that embed biological reference points related to abundance or fishing mortality, and the management measures intended to provide acceptable stock and fishery outcomes. As management by reference points can be challenging when there is data- or model-poverty, rebuilding strategies for such stocks should prioritize increasing information needed to adapt the rebuilding plan while preserving policy intent to avoid or correct undesirable stock states. We review obligations for recovery strategies under the Species at Risk Act and an ecocertification standard to evaluate where common information demands exist that could lead to efficiencies in providing advice. Existing Canadian rebuilding plans are reviewed to identify information needed to support rebuilding considerations in light of proposed regulations to support the Fish Stocks provisions. We discuss components of rebuilding strategies needed to meet proposed regulations. These include determining when rebuilding is needed, identifying the rebuilt state, and specifying a time period over which to implement a rebuilding plan. One science role is consistent communication of the plausible range of stock scenarios during the lifespan of the plan to inform expectations of decision-makers and resource users. Plan success can be enhanced by allowing for adaptation during the rebuilding period as new data, updated analyses, and revised objectives are considered. We suggest principles for developing national science guidelines for rebuilding fish stocks. Guidelines are intended to clarify expectations for, and to encourage, consistent science practices. We advocate a structured decision-making approach to developing feasible rebuilding strategies, identifying possible scenarios and eliciting objectives from resource users and decision-makers. The process can be used for data-poor contexts and maps directly into quantitative approaches such as management strategy evaluation. Finally, we provide a recommended list of elements for rebuilding strategies that should be reflected in science guidelines. [ABSTRACT FROM AUTHOR]