Terms of Reference

Recovery Potential Assessment – White Hake (Urophycis tenuis), population of the southern Gulf of St. Lawrence and population of the Atlantic and northern Gulf of St. Lawrence

Zonal Peer Review Meeting – Gulf, Maritimes, Newfoundland and Labrador, Quebec regions

January 14-16, 2015
Moncton, New Brunswick

Chairperson: Gérald Chaput (DFO Gulf Region)

Context

After the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses an aquatic species as Threatened, Endangered or Extirpated, Fisheries and Oceans Canada (DFO) undertakes a number of actions required to support implementation of the Species at Risk Act (SARA). Many of these actions require scientific information on the current status of the wildlife species, threats to its survival and recovery, and the feasibility of recovery. Formulation of this scientific advice has typically been developed through a Recovery Potential Assessment (RPA) that is conducted shortly after the COSEWIC assessment. This timing allows for consideration of peer-reviewed scientific analyses into SARA processes including recovery planning.

In the first assessment of White Hake (Urophycis tenuis Mitchill 1815) in Canadian waters from November 2013, COSEWIC assessed the species as being comprised of two populations or Designatable Units: the southern Gulf of St. Lawrence population, and the Atlantic and Northern Gulf of St. Lawrence population.

The southern Gulf of St. Lawrence population was assessed as endangered. The overall decline rate has been 91% over the past 3 generations. The area of occupancy followed a similar though less dramatic trend, and one segment of the population seems to have disappeared. While fisheries were the primary cause of the decline, it appears that high non-fishing mortality, perhaps by Grey Seal predation, may be preventing recovery. The last full assessment of the southern Gulf of St. Lawrence (NAFO Div. 4T) White Hake stock was conducted in 2001 (DFO 2001), with an update in 2005 (DFO 2005a). A review of information on the status of this stock was completed in 2011 in support of the COSEWIC assessment (Swain et al. 2012). Indicators of abundance from the research vessel and sentinel fisheries surveys were updated to 2013 (DFO 2014).

The Atlantic and northern Gulf of St. Lawrence population was assessed as threatened. Adults in this population are estimated to have declined by approximately 70% over the past three generations with most of the decline occurring before the mid-1990s. The population has remained fairly stable since then, and there has been little overall trend in area of occupancy. Restrictions on fisheries since the mid- to late 1990s over most of their range may be responsible for stabilizing their numbers. Assessments of White Hake for the Atlantic and northern Gulf of St. Lawrence population are provided for the DFO Maritimes Region area (NAFO Div. 4VWX and 5) in 2005 (DFO 2005b) and the southern Newfoundland region (NAFO Div. 3L, 3N, 3O and subdivision 3Ps) in 2002 (DFO 2002) and also to 2012 (Simpson and Miri 2013). A review of information on the status of this stock was completed in 2011 in support of the COSEWIC assessment (Simpson et al. 2012; Simons and Cook 2013).

In support of listing recommendations for White Hake by the Minister, DFO Science has been asked to undertake an RPA, based on the national RPA Guidance. The advice in the RPA may be used to inform both scientific and socio-economic aspects of the listing decision, development of a recovery strategy and action plan, and to support decision making with regards to the issuance of permits or agreements, and the formulation of exemptions and related conditions, as per sections 73, 74, 75, 77, 78 and 83(4) of SARA. The advice in the RPA may also be used to prepare for the reporting requirements of SARA s.55. The advice generated via this process will update and/or consolidate any existing advice regarding White Hake.

Objectives

• To provide up-to-date information, and associated uncertainties, to address the following elements:

Biology, Abundance, Distribution and Life History Parameters

Element 1: Summarize the biology of White Hake (Urophycis tenuis).

Element 2: Evaluate the recent species trajectory for abundance, distribution and number of populations.

Element 3: Estimate the current or recent life-history parameters for White Hake.

Habitat and Residence Requirements

Element 4: Describe the habitat properties that White Hake needs for successful completion of all life-history stages. Describe the function(s), feature(s), and attribute(s) of the habitat, and quantify by how much the biological function(s) that specific habitat feature(s) provides varies with the state or amount of habitat, including carrying capacity limits, if any.

Element 5: Provide information on the spatial extent of the areas of the distribution of White Hake that are likely to have these habitat properties.

Element 6: Quantify the presence and extent of spatial configuration constraints, if any, such as connectivity, barriers to access, etc.

Element 7: Evaluate to what extent the concept of residence applies to the species, and if so, describe the species’ residence.

Threats and Limiting Factors to the Survival and Recovery of White Hake

Element 8: Assess and prioritize the threats to the survival and recovery of White Hake .

Element 9: Identify the activities most likely to threaten (i.e., damage or destroy) the habitat properties identified in elements 4-5 and provide information on the extent and consequences of these activities.

Element 10: Assess any natural factors that will limit the survival and recovery of White Hake .

Element 11: Discuss the potential ecological impacts of the threats identified in element 8 to the target species and other co-occurring species. List the possible benefits and disadvantages to the target species and other co-occurring species that may occur if the threats are abated. Identify existing monitoring efforts for the target species and other co-occurring species associated with each of the threats, and identify any knowledge gaps.

Recovery Targets

Element 12: Propose candidate abundance and distribution target(s) for recovery.

Element 13: Project expected population trajectories over a scientifically reasonable time frame (minimum of 10 years), and trajectories over time to the potential recovery target(s), given current White Hake population dynamics parameters.

Element 14: Provide advice on the degree to which supply of suitable habitat meets the demands of the species both at present and when the species reaches the potential recovery target(s) identified in element 12.

Element 15: Assess the probability that the potential recovery target(s) can be achieved under current rates of population dynamics parameters, and how that probability would vary with different mortality (especially lower) and productivity (especially higher) parameters.

Scenarios for Mitigation of Threats and Alternatives to Activities

Element 16: Develop an inventory of feasible mitigation measures and reasonable alternatives to the activities that are threats to the species and its habitat (as identified in elements 8 and 10).

Element 17: Develop an inventory of activities that could increase the productivity or survivorship parameters (as identified in elements 3 and 15).

Element 18: If current habitat supply may be insufficient to achieve recovery targets (see element 14), provide advice on the feasibility of restoring the habitat to higher values. Advice must be provided in the context of all available options for achieving abundance and distribution targets.

Element 19: Estimate the reduction in mortality rate expected by each of the mitigation measures or alternatives in element 16 and the increase in productivity or survivorship associated with each measure in element 17.

Element 20: Project expected population trajectory (and uncertainties) over a scientifically reasonable time frame and to the time of reaching recovery targets, given mortality rates and productivities associated with the specific measures identified for exploration in element 19. Include those that provide as high a probability of survivorship and recovery as possible for biologically realistic parameter values.

Element 21: Recommend parameter values for population productivity and starting mortality rates and, where necessary, specialized features of population models that would be required to allow exploration of additional scenarios as part of the assessment of economic, social, and cultural impacts in support of the listing process.

Allowable Harm Assessment

Element 22: Evaluate maximum human-induced mortality and habitat destruction that the species can sustain without jeopardizing its survival or recovery.

Expected Publications

• CSAS Science Advisory Reports: one for each of the two Designatable Units of White Hake
• CSAS Proceedings
• CSAS Research Document(s)

Participants

• Fisheries and Oceans Canada ( Ecosystems and Oceans Science, Ecosystems and Fisheries Management sectors)
• Other invited experts

References

COSEWIC. 2013. COSEWIC assessment and status report on the White Hake Urophycis tenuis in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xiii + 45 pp.

DFO. 2001. White Hake in the southern Gulf of St. Lawrence. DFO Science Stock Status Report A3-12 (2001).

DFO, 2002. White Hake in Division 3L, 3N, 3O and subdivision 3Ps. DFO Science Stock Status Report A2-06 (2002).

DFO. 2005. White Hake in the southern Gulf of St. Lawrence (Div. 4T). DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2005/009.

DFO, 2005. White Hake in 4VWX and 5. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2005/058.

DFO. 2014. Updated indices of abundance to 2013 for stocks of six groundfish species assessed by DFO Gulf Region. DFO Can. Sci. Advis. Sec. Sci. Resp. 2014/028.

Simon, J., and Cook, A. 2013. Pre-COSEWIC Review of White Hake (Urophysis tenuis) for the Maritimes Region. DFO Can. Sci. Advis. Sec. Res. Doc. 2013/024. iv + 82 p.

Simpson, M.R., and Miri, C.M. 2013. An Assessment of White Hake (Urophycis tenuis, Mitchill 1815) in NAFO Divisions 3N, 3O, and Subdivision 3Ps. NAFO SCR Doc. 13/030.

Simpson, M.R., Miri, C.M., and Mello, L.G.S. 2012. A pre-COSEWIC assessment of White Hake (Urophycis tenuis) in Newfoundland and Labrador waters. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/038. ii + 59p.

Swain, D.P., Hurlbut, T.R., and Benoît, H.P. 2012. Pre-COSEWIC review of variation in the abundance, distribution and productivity of white hake (Urophycis tenuis) in the southern Gulf of St. Lawrence, 1971-2010. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/066. iii + 74 p.