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Rebuilding plan: White hake, Urophycis tenuis - NAFO Division 4T

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Summary

The white hake directed commercial fishery in the southern Gulf of St. Lawrence (sGSL) Northwest Atlantic Fisheries Organization (NAFO) Division 4T was closed in 1995, as the stock entered and remained in the critical zone of the Precautionary Approach (PA) framework. While overfishing is believed to be the primary cause of the initial decline during the late 1980s and early 1990s, fish harvesting-related mortality is currently relatively low and consists only of bycatch from other groundfish fisheries. At recent levels of fishing effort, the bycatch of white hake in NAFO Division 4T groundfish fisheries is estimated to have a negligible impact on the population trajectory (Rolland et al. 2022). The lack of rebuilding (and continued decline) of sGSL white hake is due to high natural mortality of Hake two years and older (Rolland et al. 2022). The sGSL white hake population seems to persist only because of the unusually high recruitment success since the year 2000. If the recruitment rate were to decrease, a decline leading to local extinction would be expected at the current level of natural mortality.

As outlined in the PA framework, the primary objective of this rebuilding plan is to promote growth of the sGSL white hake stock out of the critical zone, ensuring that removals from all fishing sources are kept to the lowest possible level until the stock has cleared this zone. The rebuilding target for the plan will be to grow the stock so that it is above the Limit Reference Point (LRP) of 12,800 t with a high likelihood (>75%). If the rebuilding target can be reached, the long-term management objective under the Integrated Fisheries Management Plan (IFMP) will be to continue the stock’s growth toward the healthy zone and then maintain the stock’s Spawning Stock Biomass (SSB) in that zone. Achieving and maintaining the SSB in the healthy zone would be to the benefit of all Canadians, including:

Unfortunately, the prognosis for this stock is pessimistic. At the current high level of natural mortality of large (mature) individuals, and the shift in distribution out of the inshore waters to deeper waters to avoid predation, rebuilding of this stock to sustainable harvestable levels is highly improbable in the short and long terms (Rolland et al. 2022). The high fecundity of this species seems to be the only reason sustaining the presence of this stock in the sGSL, despite the many factors impeding the rebuilding of the stock. These prevailing conditions are such that a rebuilding timeline to the rebuilding target cannot be calculated, as the stock is projected to continue to decline even in the absence of fishing mortality, due to the high level of natural mortality (Roland et al. 2022). During each review of the plan, the factors limiting the stock’s potential for growth will be reassessed to determine if they are still influencing the stock and whether a rebuilding timeline can be calculated. In the meantime, this rebuilding plan aims at minimizing, to the extent possible, further declines of the stock. This is to preserve the stock such that, should the prevailing conditions limiting the stock’s recovery change, the stock retains the potential to rebuild.

Guided by the PA framework, management actions are set out in this rebuilding plan to maintain low fishing mortality to support rebuilding while continuing to monitor and assess the stock. This will be done through:

Acronyms used in this document

AFS - Aboriginal Fisheries Strategy

COSEWIC - Committee on the Status of Endangered Wildlife in Canada

CSAS - Canadian Scientific Advisory Secretariat

DFO - Fisheries and Oceans Canada

DU - Designated Unit as defined by the COSEWIC (species, subspecies, variety, or geographically or genetically distinct population that may be assessed by COSEWIC, where such units are both discrete and evolutionarily significant)

F - Fishing mortality

FSC - Food, Social and Ceremonial fisheries by First Nations and Indigenous organizations

FSP - Fish Stocks Provisions in the amended Fisheries Act (2019)

GGAC - Gulf Groundfish Advisory Committee

HCR - Harvest Control Rules also called Harvest Decision Rules

IFMP - Integrate Fisheries Management Plan

ITQ - Individual transferable quota

LRP - Limit Reference Point at the critical-cautious zone boundary of the precautionary approach framework

M - Natural mortality

MCMC - Markov chain Monte Carlo; class of algorithms for sampling from a probability distribution

NAFO - Northwest Atlantic Fisheries Organization

PA - Precautionary Approach

RR - Removal Reference is the maximum acceptable removal rate for the stock

RV survey - Research Vessel survey (scientific) conducted annually in September

SARA - Species at Risk Act

sGSL - Southern Gulf of St. Lawrence

SSB - Spawning Stock Biomass

t - Metric ton, which is 1,000 kg or 2,204.6 lbs

TAC - Total Allowable Catch

TRP - Target Reference Point determined by productivity objectives for the stock, broader biological considerations and social and economic objectives for the fishery

USR - Upper Stock Reference point at the cautious-healthy zone boundary

Foreword

In 2009, Fisheries and Oceans Canada (DFO) developed a Fisheries Decision-Making Framework Incorporating the Precautionary Approach (PA Policy)Footnote 1 under the auspices of the Sustainable Fisheries FrameworkFootnote 2 . It outlines the departmental methodology for applying the precautionary approach (PA) to Canadian fisheries. A key component of the PA Policy requires that when a stock has declined to or below its limit reference point (LRP), a rebuilding plan must be in place with the aim of having a high probability of the stock growing above the LRP within a reasonable timeframe.

In addition, under section 6.2 of the Fish Stocks provisions (FSP) in the amended Fisheries Act (2019), rebuilding plans must be developed and implemented for prescribed major fish stocks that have declined to or below their LRP. This legislated requirement is supported by section 70 of the Fishery (General) Regulations (FGR), which set out the required contents of those rebuilding plans and establishes a timeline for each rebuilding plan’s development.

The purpose of this plan is to identify the main rebuilding objectives for white hake in NAFO Division 4T, as well as the management measures that will be used to achieve these objectives. This plan provides a common understanding of the basic “rules” for rebuilding the stock. This stock is prescribed in the Fishery (General) Regulations (section 69) and thus is subject to section 6.2 of the Fisheries Act and regulatory requirements.

The objectives and measures outlined in this plan are applicable until the stock has reached its rebuilding target. Once the stock is determined to be at the target, the stock will be managed through the standard Integrated Fisheries Management Plan (IFMP) or other fishery management processes in order to fulfill the requirements of the FSP. Management measures outlined in this rebuilding plan are mandatory, and may be modified or further measures added if they fail to result in stock rebuilding.

This rebuilding plan is not a legally binding instrument which can form the basis of a legal challenge. The plan can be modified at any time and does not fetter the Minister's discretionary powers set out in the Fisheries Act. The Minister can, for reasons of conservation or for any other valid reasons, modify any provision of the rebuilding plan in accordance with the powers granted pursuant to the Fisheries Act.

Decisions flowing from the application of this rebuilding plan must respect the rights of Indigenous peoples of Canada recognized and affirmed by section 35 of the Constitution Act (1982), including those through modern treaties. Where DFO is responsible for implementing a rebuilding plan in an area subject to a modern treaty, the rebuilding plan will be implemented in a manner consistent with that agreement. The plan should also be guided by the 1990 Sparrow decision of the Supreme Court of Canada, which found that where an Aboriginal group has a right to fish for food, social and ceremonial purposes, it takes priority, after conservation, over other uses of the resource.

The Honourable Diane Lebouthillier, P.C., M.P
Minister of Fisheries, Oceans and the Canadian Coast Guard

1.0 Introduction and context

1.1 Population and distribution

White hake (Urophycis tenuis) is a demersal North Atlantic fish occurring on continental shelves and their slopes from Iceland to North Carolina. The southern Gulf of St. Lawrence (sGSL) population of white hake overwinters in the Laurentian Channel in NAFO Division 4T and subdivision 4Vn (the Cabot Strait), occurring at depths greater than 200 m (Chouinard and Hurlbut 2011). In summer, sGSL hake either remain in relatively deep water (> 100 m) or move into shallow water (mostly < 50 m) along the Gulf coasts of New Brunswick, Prince Edward Island, mainland Nova Scotia and southwestern Cape Breton Island. Historically, the inshore migration generally began in April-May and proceeded rapidly until June, when most of the traditional summer habitats were occupied. The return migration to the overwintering grounds in the Laurentian Channel occurred in November and December (Darbyson and Benoît 2003), but now appears to occur in July. The proportion of hake occurring in inshore areas has declined over time, with hake virtually absent from these areas in recent years (Swain et al. 2016). This shift in the distribution of adult white hake into deeper offshore water is in response to the increased predation by Grey Seal in their preferred habitat (Hammill et al. 2014; Swain et al. 2015).

1.2 Biology

White hake are highly fecund, with buoyant eggs that generally occur in the upper water layer. The species has an extended juvenile stage, remaining in the upper water layer for 2 to 3 months (depending on water temperature) prior to settlement. Spawning in the eastern Northumberland Strait occurs from June to September, with peak spawning in late June. Spawning in other areas occurs in early spring and a second summer spawning has been reported from the Scotian Shelf. Size at 50% maturity in Canadian waters ranges from 40 to 54 cm for females and 37 to 44 cm for males (COSEWIC 2013).

A dramatic contraction of the age composition of sGSL white hake has occurred since 1971 (Swain et al. 2016). Fish 10 years and older were commonly observed in the survey catches in the 1970s and 1980s, but no hake over 7 years of age has been observed in the survey since 1998. White hake 45 cm and longer and 4 years and older are considered to be mature in the sGSL population. Based on the research vessel (RV) survey catches, few fish have survived beyond 5 years of age since about 2000. This means that spawning by white hake is now limited to 2 age groups, ages 4 and 5 years.

Generation time is estimated to be 9 years (COSEWIC 2013).

1.3 Habitat requirements

White hake are a groundfish species that live their adult lives in depths of a few meters to almost 1000 meters, preferring sandy and muddy bottoms. White hake are found near the bottom and are commonly captured over fine sediment substrates such as mud but are also reported on sand and gravel. They adjust their depth distribution to find temperatures in the range of 4-8° C. Larger fish generally occur in deeper waters whereas juveniles typically occupy shallow areas close to shore or over shallow offshore banks (COSEWIC 2013). Inshore areas and eelgrass beds are thought to be important nursery habitats for demersal immature white hake. Juveniles appear to stay in shallow water for a year and migrate to offshore locations during their second year (Fahay and Able 1989).

1.4 Ecosystem interactions

Demersal juveniles feed primarily on polychaetes, shrimps, and other crustaceans, but adults feed on fish, including juveniles of their own species and shrimps and other crustaceans (Chang et al. 1999). Predators of pelagic juvenile white hake include Atlantic puffin and Arctic tern. White hake are recorded from the stomachs of Atlantic cod and white hake. The main threat to the white hake population in the sGSL is an exceedingly high level of natural mortality on adult fish, attributed to increased predation by Grey Seals (Benoît et al. 2011a,b, Hammill et al 2014, Swain et al. 2015).

1.5 Fishery

Map showing the the North Atlantic Fisning Organization (NAFO) divisions and subdivisions along the Canadian Atlantic coast from Newfoundland to Nova Scotia. Division 4T are used to define the boundaries of the southern Gulf of St. Lawrence white hake stock.
Figure 1. North Atlantic Fishing Organization (NAFO) divisions and subdivisions.
Description

Figure 1
Map showing the the North Atlantic Fisning Organization (NAFO) divisions and subdivisions along the Canadian Atlantic coast from Newfoundland to Nova Scotia. Division 4T are used to define the boundaries of the southern Gulf of St. Lawrence white hake stock.

The Southern Gulf of St. Lawrence (sGSL) groundfish fishery targets nine major stocks (Table 1), distributed and managed within the North Atlantic Fishing Organization (NAFO) Division 4RST and subdivision 4Vn (Figure 1). Although the present rebuilding plan focuses on white hake, the management of this stock is closely linked to all other groundfish stocks in NAFO Division 4T.

Since the early 1990s, unique management measures have been put in place to address the severe decline of many groundfish stocks, and in the worst cases their collapse, resulting in the introduction of moratoria and significant quota reductions. Unfortunately, the outlook for many of these stocks remains precarious with five out of nine stocks currently in the critical zone. Of these, 4 are prescribed in the Fishery (General) Regulations (section 69) and therefore subject to section 6.2 of the Fisheries Act and regulatory requirements (Table 1).

Four of the 9 stocks have also been assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as potential candidates for listing under the Species at Risk Act (SARA) (Table 1; both redfish species are being considered as one stock for the purpose of management).

Most groundfish stocks managed within NAFO Division 4T overlap in both space and time, which increases the likelihood of non-target groundfish species being caught incidentally in other directed groundfish fisheries. As management measures are being developed for specific fisheries, it becomes critical to consider all potential interactions and sources of fishing mortality. Several commercial groundfish fisheries are occurring in the sGSL (Table 1), and bycatch of white hake can still occur in these fisheries. White hake are also caught as part of a recreational fishery or by First Nations for community harvesting, or for Food, Social and Ceremonial (FSC) purposes.

Table 1. Most common groundfish stocks harvested in the southern Gulf of St. Lawrence.

Atlantic cod1, Gadus morhua

Atlantic halibut Hippoglossus hippoglossus

American plaice 1, Hippoglossoides platessoides

Greenland halibut (turbot or black halibut), Reinhardtius hippoglossoides

White hake1, Urophycis tenuis

Winter flounder1, Pseudopleuronectes americanus

Witch flounder Glypocephalus cynoglossus

Redfish Sebastes fasciatus and Sebastes mentella

  • Yellowtail flounder (Pleuronectes ferrugineus)

    • 1 Stock prescribed in the Fishery (General) Regulations (section 69) and thus is subject to section 6.2 of the Fisheries Act and regulatory requirements.
    2 Year since the stock has been assessed in the critical zone of the PA framework.
    3 Status as presented in the latest COSEWIC assessment and status report. At the time of publication of this rebuilding plan, no decision regarding listing under SARA has been made

    The Gulf Groundfish Advisory Committee (GGAC), which brings together representatives of the fishing industry, processors, Indigenous groups, DFO and provincial government representatives from the 4 Atlantic Provinces and Quebec, provides advice and recommendations to the Department for the management of commercially exploited Gulf of St. Lawrence groundfish stocks (NAFO Divisions 4RST, 3Pn and subdivision 4Vn). The advisory committee meets every 2 years and serves as a forum for sharing results of recent stock assessments, for industry stakeholders and right holders to address issues affecting groundfish fisheries, and, most importantly, for DFO to solicit input from committee members on key management decisions.

    In 2017, a Groundfish - Gulf of St. Lawrence NAFO Subdivisions 3Pn, 4Vn and Divisions 4RST Integrated Fisheries Management Plan (IFMP) was developed by DFO in consultation with the GGACFootnote 3. The IFMP provides detailed operational management information pertaining to mixed groundfish fisheries in the sGSL, including the white hake bycatch fishery. An update to the Gulf Groundfish IFMP is underway and will account for stocks that are subject to a rebuilding plan, as all management measures outlined in the plan will supersede or will be in addition to those in the IFMP.

    1.6 Overview of the fishery socio-economic and cultural importance

    The fishery for white hake in NAFO Division 4T has historically been the third or fourth most important groundfish fishery in the southern Gulf, with annual landings that averaged 5,675 t from 1960 to1994. The fishery was carried out mainly by small inshore vessels and was strongly affected by weather and local market conditions. Both fixed and mobile gears were used in the hake fishery, which was concentrated in the Northumberland Strait, on the western end of Prince Edward Island, and between Prince Edward Island and Cape Breton Island (DFO 2004).

    Landings of white hake in NAFO Div. 4T fluctuated between about 4,000 and 7,000 t between 1961 and 1978. Landings then rose sharply to a peak of 14,000 t in 1981, followed by a rapid decline to an average of 5,000 t from 1985 to1992. The white hake fishery was not managed by a TAC until a precautionary TAC of 12,000 t was established for the 1982 fishery. The TAC was subsequently reduced to 9,400 t in 1987, 5,500 t in 1988, 3,600 t in 1993, and 2,000 t in 1994. Following consultations with industry in 1994, the Fisheries Resource Conservation Council (FRCC) recommended that “there be no directed fishing for NAFO Div. 4T white hake in 1995, and that bycatches be kept to the lowest possible level". In response to these recommendations, the fishery for white hake was closed in January 1995, and has remained under moratorium since then (Swain et al. 2016). As white hake was still being caught as bycatch in other groundfish commercial directed, recreational and Aboriginal Fisheries Strategy (AFS) fisheries, a bycatch TAC of 30 t was implemented in the mid-2000s.

    In Eastern Canada, between 2011 and 2020, the landed value of the 4T white hake harvest has been distributed between the provinces of:

    White hake was reported as bycatch when harvesters were directing for:

    In 2020, 83 commercial groundfish licence holders reported a total of 12 t in landings of white hake in NAFO 4T with an associated value of $9,179 (Table 2). Most groundfish harvesters in the sGSL also have access (i.e., fishing licences) to other species of greater commercial value, such as snow crab, shrimp, and lobster, while a limited number of harvesters have specialized in groundfish fishing only.

    Table 2. White hake bycatch landings in the southern Gulf of St. Lawrence (NAFO Division 4T) from 2011 to 2020.

    1Preliminary data.
    Catches from the recreational and FSC fisheries, and catches from the scientific RV survey and sentinel fishery are not included since removal estimates are not available. Source: DFO; Gulf, Québec and Newfoundland and Labrador Regions

    There is currently an authorized groundfish recreational fishery with access to white hake in the waters adjacent to the Maritime Provinces in the sGSLFootnote 4 . This fishery is open for 5 weeks or less per year. Recreational fishing within 50 meters of the coastline of New Brunswick is allowed from April 15th to October 1st. Anglers can keep a daily catch limit ranging from 5 to 15 groundfish, regardless of species, including a total of not more than 5 cod and/or white hake in the aggregate. There is also spring-summer recreational groundfish fishery in the Saguenay Fjord, St. Lawrence Estuary and Gulf of St. Lawrence with access to white hakeFootnote 5.

    A winter recreational groundfish fishery, commonly known as ice fishing, is conducted in the province of Quebec and is open for approximately 3 months from January to March in the Saguenay FjordFootnote 6 . The fishery is subject to a daily bag limit of 5 groundfish. Although redfish is the main species caught, white hake is among other species caught in this fishery. No removal estimates are available for white hake in any of these recreational fisheries, but the amount is likely to be minimal (from qualitative field observations obtained from Conservation and Protection fishery officers).

    Under the Aboriginal Community Fishing Licence RegulationsFootnote 7 and AFS agreementsFootnote 8, Indigenous communities can catch white hake if they hold groundfish licences. White hake can also be fished as part of the Aboriginal FSC fishery. FSC fisheries are managed, where licensed, under the Aboriginal Community Fishing Licence Regulations and AFS agreements. The species caught under FSC licence conditions are not allowed to be sold and there are no estimates available for removals of white hake in this fishery. However, the quantity is likely minimal (from qualitative field observations obtained from Conservation and Protection fishery officers).

    1.7 Involvement of stakeholder and Indigenous groups in the development of the plan

    A first meeting was held on September 24, 2020, with industry stakeholders and Indigenous partners to discuss the rebuilding plan development process and to solicit participation in a Gulf Groundfish Rebuilding Plans Working Group that would assist the department in developing the plans. Due to Covid restrictions limiting face-to-face meetings, DFO developed a questionnaire outlining rebuilding objectives and proposed management measures as an alternative mean to solicit input from stakeholders and rights holders. The questionnaire was sent to members of the Gulf Groundfish Rebuilding Plan Working Group on December 15, 2020. An information session with Indigenous partners was also held on January 26, 2021.

    The purpose of the questionnaire was to initiate discussions and gather views on rebuilding options for four groundfish stocks, including white hake. Stakeholders and rights holders were invited to comment on the proposed objectives and rebuilding measures, and to recommend alternative or additional rebuilding measures to the management measures presented. Although consolidated comments were sought through the Gulf Groundfish Rebuilding Plan Working Group, any member from the fishing industry, First Nations or Indigenous organizations could submit individual comments in writing.

    2.0 Stock status and stock trends

    In 2003, the Privy Council Office, on behalf of the Government of Canada, published a framework applicable to all federal government departments that set out guiding principles for the application of precaution to decision-making about risks of serious or irreversible harm where there is a lack of full scientific certainty.

    A Fisheries Decision-Making Framework Incorporating the Precautionary Approach was developed (DFO 2009), and applies where decisions on harvest strategies or harvest rates for a stock must be taken to determine TAC or other measures to control harvests. The framework applies to key harvested stocks managed by DFO: those stocks that are the specific and intended targets of a fishery, whether in a commercial, recreational or subsistence fishery. In applying the framework, all removals of these stocks from all types of fishing must be taken into account.

    The following are the primary components of the generalized framework:

    Limit reference points (LRP) as defined by the Precautionary Approach Framework (DFO 2009) were estimated for the white hake stock (Table 3). Since the comprehensive stock assessment is normally conducted every 5 years, an interim biomass indicator associated with the LRP was developed to report on the stock status without going through a full assessment.

    Table 3. Summary of the Precautionary Approach Framework reference points and COSEWIC/SARA status for NAFO Division 4T white hake.

    PA reference point

    COSEWIC status: Endangered (COSEWIC 2013
    SARA status: No schedule, no status

    1Catch rate index LRP equivalent: the three-year moving average of the annual Research Vessel (RV) survey biomass index for commercial-sized white hake (≥ 45 cm total length) used as the indicator of stock status in the interim years of the multi-year management cycle.

    The most recent stock assessment for white hake in sGSL was conducted in 2021 (DFO 2021, Rolland et al. 2022), using a population model similar to that used by Swain et al. (2016).

    Estimated spawning stock biomass (SSB) of white hake in the sGSL. The black line is the median estimate of SSB, the heavy shading is the middle 50% of estimates and the light shading is the 95% confidence limits. The circles show the median estimates of SSB obtained by the 2015 recovery potential assessment model. The red horizontal line is the limit reference point (LRP) of 12,800 t. Estimated SSB was at a high level from 1979 to 1987, averaging 56,425 t and peaking at 63,400 t in 1981. It then fell sharply in the late 1980s and 1990s, dropping by 85% to 8,860 t in 2000. It has remained at a very low level ever since. The estimated SSB at the start of 2019 was 7,396 t, around 13% of the average level from 1979 to 1987.
    Figure 2. Estimated SSB of white hake in the sGSL. The black line is the median estimate of SSB, the heavy shading is the middle 50% of estimates and the light shading is the 95% confidence limits. The circles show the median estimates of SSB obtained by the 2015 recovery potential assessment model (Swain et al. 2016). The red horizontal line is the LRP of 12,800 t (DFO 2021).
    Description

    Figure 2
    Estimated spawning stock biomass (SSB) of white hake in the sGSL. The black line is the median estimate of SSB, the heavy shading is the middle 50% of estimates and the light shading is the 95% confidence limits. The circles show the median estimates of SSB obtained by the 2015 recovery potential assessment model. The red horizontal line is the limit reference point (LRP) of 12,800 t. Estimated SSB was at a high level from 1979 to 1987, averaging 56,425 t and peaking at 63,400 t in 1981. It then fell sharply in the late 1980s and 1990s, dropping by 85% to 8,860 t in 2000. It has remained at a very low level ever since. The estimated SSB at the start of 2019 was 7,396 t, around 13% of the average level from 1979 to 1987.

    Estimated spawning stock biomass (SSB) was at a high level from 1979 to 1987, averaging 56,425 t and peaking at 63,400 t in 1981 (Figure 2). Estimated SSB then declined sharply in the late 1980s and the 1990s, falling below the LRP in 1995. By 2000, the SSB fell to 8,860 t (i.e.: 69% of LRP) and has remained at a very low level since then. Estimated SSB at the start of 2019 was 7,396 t, about 13% of the average level in 1979 to 1987.

    There has not been any improvement in the annual September RV survey indices of abundance or distribution of white hake since the Recovery Potential Assessment (DFO 2016). The 3 moving average values of the biomass index for commercial-sized (>45 cm total length) is presented by the red solid line in figure 3. This value is 0.46 kg per tow for the 2017 to 2019 period, which represents only 44% of the proposed abundance target for recovery (1.04 kg per tow, dotted horizontal line in figure 3) (DFO 2020).

    In the 1970s and the 1980s, white hake were common in inshore waters of the sGSL in the summer and early fall. In September in the 1970s, the majority of sGSL Hake occurred in these inshore waters (68% of adults, 58% of all sizes). By the 2000s, these proportions had dropped to 6% of adults and 8% of all sizes (Figure 4). In the past, these inshore waters contained important spawning grounds for hake. It is only in these inshore areas that the spawning grounds and spawning timing of sGSL white hake are relatively well known (Swain et al. 2016).

    Graphic showing the annual research vessel survey index of commercial-sized (≥ 45 cm total length) white hake in the southern Gulf of St. Lawrence, 1971 to 2019. The black circles and solid black line are the stratified mean estimates and the grey shading denotes the 95% confidence intervals of the annual means. The red solid line is the three-year moving average shown in correspondence to the third year of the block of years. The horizontal dotted line is the proposed abundance target for recovery of 1.04 kg per tow. The index value was 0.46 kg per tow for the 2017 to 2019 period, which represents only 44% of the proposed abundance target for recovery. Data from 2003 is omitted from the figure as an uncalibrated vessel was used in that year.
    Figure 3. Annual RV survey index (kg per tow) of commercial-sized (> 45 cm total length) white hake in the southern Gulf of St. Lawrence, 1971 to 2019. The black circles and solid black line are the stratified mean estimates and the grey shading denotes the 95% confidence intervals of the annual means. The red solid line is the three-year moving average shown in correspondence to the third year of the block of years. The horizontal dotted line is the threshold value of 1.04 kg per tow. Data from 2003 is omitted from the figure as an uncalibrated vessel was used in that year (DFO 2020).
    Description

    Figure 3
    Graphic showing the annual research vessel survey index of commercial-sized (≥ 45 cm total length) white hake in the southern Gulf of St. Lawrence, 1971 to 2019. The black circles and solid black line are the stratified mean estimates and the grey shading denotes the 95% confidence intervals of the annual means. The red solid line is the three-year moving average shown in correspondence to the third year of the block of years. The horizontal dotted line is the proposed abundance target for recovery of 1.04 kg per tow. The index value was 0.46 kg per tow for the 2017 to 2019 period, which represents only 44% of the proposed abundance target for recovery. Data from 2003 is omitted from the figure as an uncalibrated vessel was used in that year.

    There has not been a return to inshore waters of commercial-sized white hake to the levels observed in the 1970s (Swain et al. 2016, DFO 2016). The majority of commercial-sized white hake caught during the annual September research vessel survey in the sGSL are now distributed in the deep waters along the edge of the Laurentian Channel, with few to any fish in shallower waters of the sGSL (Figure 4). It is likely that much like Atlantic cod and winter skate, white hake is facing a predation-driven Allee effect or predator-pit situation (Swain and Benoit 2015) in which the per capita rate of population growth decreases as population size decreases. This is opposite to the usual behavior of populations at low abundance. This Allee effect suggests that the LRP should be revised to a greater value than where it currently is.

    Figure illustrating changes in the spatial distribution of white hake catches by blocks of years in the bottom trawl survey carried out by a research vessel in the southern Gulf of St Lawrence, from 1971 to 2020. In the 1970s, White Hake occurred predominately in shallow inshore areas (≤ 50 m depth) in September (Fig. 5). The 1980s showed increasing abundance of White hake in deeper waters offshore (> 100 m) along the slopes of the Laurentian Channel and in the Cape Breton Trough, while still remaining abundant in the inshore areas. Since then, adult distribution progressively shifted into deeper waters. By the 2000s, the proportion of white hake inshore was almost nonexistent with white hake occurring almost exclusively in the offshore areas of the Laurentian Channel and Cape Breton Trough.
    Figure 4. Annual RV survey index (kg per tow) of commercial-sized (≥ 45 cm total length) white hake in the southern Gulf of St. Lawrence, 1971 to 2019. The black circles and solid black line are the stratified mean estimates and the grey shading denotes the 95% confidence intervals of the annual means. The red solid line is the three-year moving average shown in correspondence to the third year of the block of years. The horizontal dotted line is the threshold value of 1.04 kg per tow. Data from 2003 is omitted from the figure as an uncalibrated vessel was used in that year (DFO 2020).
    Description

    Figure 4
    Figure illustrating changes in the spatial distribution of white hake catches by blocks of years in the bottom trawl survey carried out by a research vessel in the southern Gulf of St Lawrence, from 1971 to 2020. In the 1970s, White Hake occurred predominately in shallow inshore areas (< 50 m depth) in September (Fig. 5). The 1980s showed increasing abundance of White hake in deeper waters offshore (> 100 m) along the slopes of the Laurentian Channel and in the Cape Breton Trough, while still remaining abundant in the inshore areas. Since then, adult distribution progressively shifted into deeper waters. By the 2000s, the proportion of white hake inshore was almost nonexistent with white hake occurring almost exclusively in the offshore areas of the Laurentian Channel and Cape Breton Trough.

    The status of this population remains very precarious. The spawning stock, consisting of ages 4 to 10 years and older in the past, now consists mostly of 4 years old. This would be expected to result in a serious decline in productivity and represents a high risk to this population, with only a single reproductive cohort. Natural mortality remains extremely high and this population currently persists only because recruitment rates have also increased to extreme levels. The causes of these unusually high recruitment rates are not known and it is not known whether they will persist. Projections indicate that if these rates declined to the levels observed from 2000 to 2010 the population would begin to rapidly decline. Nevertheless, the 2000 to 2010 recruitment rates were still considered to be exceptionally high, though not as extreme as some of the rates estimated more recently from 2015 to 2019. Assuming that productivity of this population remains at the levels estimated for recent years; projections (2019-2044) indicate a gradual decline even with no fishing mortality. An approximately 40% decline in SSB is projected over 25 years. In the absence of fishing mortality, the probability that SSB would be below 4,000 t, 2,000 t, or 1,000 t was estimated to be 46%, 22%, and 8% respectively after 25 years. Results were similar at bycatch of 20 t, the average level of reported landings in recent years (Rolland et al. 2022).

    2.1 COSEWIC assessment/SARA considerations

    In November 2013, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed the 2 populations of white hake or designated units (DU):

    The sGSL DU consists of white hake occurring in NAFO Division 4T and the northwest portion of NAFO Subdivision 4Vn. Hake in the sGSL DU is currently under consideration for listing under the Species at Risk Act (SARA). At the time of publication of this rebuilding plan, no decision regarding listing had been made.

    2.2 Indigenous knowledge

    DFO aims to incorporate Indigenous traditional knowledge and traditional ecological knowledge considerations in science processes as participants to peer reviews meetings, and into fisheries management planning as members of GGAC. As required, indigenous knowledge is also gathered through consultations with First Nations and other Indigenous organizations.

    3.0 Probable causes for the stock’s decline

    Levels of fishing mortality that were sustainable in the 1970s became unsustainable when natural mortality began to increase in the early 1980s combined with fishing mortality that also rapidly increased in the late 1980s and early 1990s, contributing to the collapse of the NAFO Division 4T white hake stock (Figure 5). While overfishing is believed to have been the primary cause of white hake’s initial decline during the late 1980s and early 1990s, bycatch fishing mortality has been relatively low since the moratorium introduced in 1995. At recent levels of fishing effort, the bycatch of white hake in Division 4T groundfish fisheries is estimated to have a negligible impact on the population trajectory. The lack of rebuilding (and continued decline) of sGSL white hake is due to high natural mortality of hake 2 years and older. The white hake stock is currently sustained by unusually high recruitment rates which depend largely on the productivity of a single cohort (age 4) each year (Rolland et al. 2022).

    In the past, the inshore waters contained important spawning grounds for white hake. One of these spawning grounds, Baie Verte in the Northumberland Strait, was abandoned in the late 1990s (Hurlbut 2012). Hake now appears to be abandoning the remaining inshore spawning grounds (e.g. St. Georges Bay). Although recruitment is presently unusually high, loss of localized spawning components severely compromises the productive potential of a stock. The shift in distribution of white hake out of these inshore waters and into deeper water in the Cape Breton Trough and along the Laurentian Channel appears to be a response to increased risk of predation by grey seals (Swain et al. 2015). It is likely that much like Atlantic cod and winter skate, white hake is facing a predation-driven Allee effect or predator-pit situation (Swain and Benoit 2015) in which the per capita rate of population growth decreases as population size decreases. It is unlikely that Hake will return to these inshore areas until predation risk in these areas is substantially reduced.

    Graph showing fluctuations in fishing mortality (F) in red and natural mortality (M) in blue by age group, from 1950 to 2023. In most years, the main source of mortality for white hake in the southern Gulf of St Lawrence was natural mortality. For juveniles aged 2 to 3 years, the estimated value of M increased from 44% annually in 1978 to 68% in 2013. For fish aged 4 to 5 years, the increases in the value of M were even more extreme, rising from 32% in 1978 to an average value of 86% since 2000. For ages 6 and over, the M value increased from 27% to 81% over the same period.
    Figure 5. Estimated instantaneous rates of fishing and natural mortality (F and M, respectively) by age group (ages 2-3, ages 4-5, ages 6+). The values shown for F are abundance-weighted averages for each age length group (1978:2006). Blue lines and red circles show the median estimates. Shading and vertical lines show their 95% confidence intervals based on MCMC sampling. The right-hand axis shows the corresponding annual mortality. Average Fs for ages 2 and 3 are not shown since they were negligible (< 0.001 in all years, < 0.00005 since 2000)(Rolland et al. 2022).
    Description

    Figure 5
    Graph showing fluctuations in fishing mortality (F) in red and natural mortality (M) in blue by age group, from 1950 to 2023. In most years, the main source of mortality for white hake in the southern Gulf of St Lawrence was natural mortality. For juveniles aged 2 to 3 years, the estimated value of M increased from 44% annually in 1978 to 68% in 2013. For fish aged 4 to 5 years, the increases in the value of M were even more extreme, rising from 32% in 1978 to an average value of 86% since 2000. For ages 6 and over, the M value increased from 27% to 81% over the same period.

    The increase in recruitment success may be due to a relaxation of density-dependent constraints on productivity. White hake are known to be cannibalistic (Davis et al. 2004; Benoît and Swain 2008), and cannibalism is one factor that may promote strong compensation in their stock-recruit relationship. However, the increase in recruitment rate at the low SSB seen since the mid-1990s seems to be too great to be attributed solely to compensation (Rolland et al. 2022). Increases in the survival of small fish appear to be widespread throughout this ecosystem since the mid-1990s (Benoît and Swain 2008, Swain et al. 2012, Swain and Benoît 2015), and this ecosystem change may contribute to the increased recruitment rate of white hake in recent years. At the current level of natural mortality, if recruitment rates were to decline even slightly to the levels seen in the 2000s, the extinction risk for this stock would increase (Rolland et al. 2022).

    At current level of natural mortality, rebuilding of this stock is highly improbable, even in the absence of fishing. The sGSL white hake population was projected forward 25 years (2019-2044) assuming that productivity would remain at recent levels (i.e.: highest recruitment rates on record). SSB was estimated to decline by 38.7% with no catch and 39.3% with annual bycatch of 20 t. With annual bycatch of 150 t to 350 t, SSB was estimated to decline by 43% to 48%. With bycatch of 500 t to 1,500 t, SSB declined by 53% to 70% (Figure 6) (DFO 2021, Rolland et al. 2022). As expected, probabilities of SSB decline were estimated to be much greater when recruitment rates were drawn from the much lower rates from 2000 to 2010 (Rolland et al. 2022).

    Studies have shown that grey seals are important predators of multiple groundfish species in the sGSL, including white hake (Swain and Benoît 2015, Swain et al. 2019). The increasing population of grey seals (DFO 2022) has led to increased predation on multiple commercially valuable species, creating conflicts with fisheries and generating calls for some form of predator controls (DFO 2011b, Swain and Benoît 2015; Neuenhoff et al. 2019 and Rossi et al. 2021). Depending upon future white hake recruitment productivity, a reduction of 50% or more in the natural mortality of adult hake may be required to rebuild the population above the COSEWIC based recovery target (or above the LRP) (DFO 2016, DFO 2021). The population size of grey seals that would correspond to this 50% reduction in natural mortality has not been determined (Benoît et al. 2011a,b; DFO 2011).

    Given the current understanding and best available scientific evidence, loss or degradation of the sGSL white hake stock’s fish habitat is unlikely to have contributed to the stock’s decline. Physical habitat characteristics are not considered to have been degraded. On the other hand, access of this habitat appears to be restricted by the very high risk of predation by grey seals that now exist in inshore areas in summer (Swain et al. 2015). Historically, the majority of adult white hake utilized these inshore areas in summer, but it is unlikely that they will resume use of these areas until predation risk is reduced (DFO 2016).

    Graph showing estimated historical (green) and projected (other colors) spawning stock biomass (SSB) of sGSL white hake at different levels of bycatch as scenarios. The white hake population was projected over 25 years assuming that productivity would remain at recent levels. The projections indicate consistent declines in SSB with all bycatch scenarios.
    Figure 6. Estimated historical (green) and projected (other colors) SSB of sGSL white hake at different levels of bycatch as scenarios (0, 20, 150, 750 and 1,500 t). Lines and circles are the median estimate. Shading indicates the 50% (dark) and 95% (light) confidence intervals. These intervals are shown for the historical estimates and the projections at the highest bycatch levels in each panel. For the projections recruitment rates are sampled from the 2000-2019 period. The horizontal dashed lines represent the LRP of 12,800 t and the level of 2,000 t which represents the limit of a very high risk of local extinction (Rolland et al. 2022).
    Description

    Figure 6
    Graph showing estimated historical (green) and projected (other colors) spawning stock biomass (SSB) of sGSL white hake at different levels of bycatch as scenerios. The white hake population was projected over 25 years assuming that productivity would remain at recent levels. The projections indicate consistent decline in SSB with all bycatch scenarios.

    4.0 Measurable objectives aimed at rebuilding the stock

    4.1 Rebuilding target and timeline

    As outlined in the Precautionary Approach framework (PA), the primary objective of this rebuilding plan is to promote stock growth out of the critical zone (e.g. grow the stock beyond the LRP), by ensuring removals from all fishing sources are kept to the lowest possible level until the stock has cleared this zone. Within the critical zone, this objective remains the same whether the stock is declining, stable or increasing. Based on the PA framework, the overarching objective for NAFO Division 4T white hake is therefore for the stock to grow out of the critical zone. The rebuilding target for the plan will be to grow the stock so that it is above the LRP (12,800 t) with a high likelihood (>75%). If the rebuilding target can be reached, the long-term management objective under the IFMP will be to maintain the stock’s growth toward the healthy zone and then maintain the stock’s SSB in that zone. This long-term objective would be to the benefit of all Canadians, including:

    Unfortunately, the prognosis for this stock is pessimistic. At the current high level of natural mortality on large (mature) individuals, and shift in distribution out of the inshore waters and into deeper waters to avoid predation, rebuilding of this stock to sustainable harvestable levels is highly improbable in the short and long terms, even in the absence of fishing (Rolland et al. 2022). The high fecundity of this species seems to be the only reason sustaining the presence of this stock in the sGSL, despite the many factors impeding the rebuilding of the stock. These prevailing conditions are such that a rebuilding timeline to the rebuilding target cannot be calculated as the stock is projected to continue to decline even in the absence of fishing mortality, due to the high level of natural mortality (Roland et al. 2022). During each review of the plan, the factors limiting the stock’s potential for growth will be reassessed to determine if they are still influencing the stock and if a rebuilding timeline can be calculated. In the meantime, and in compliance to the PA framework, this rebuilding plan still aims at minimizing, to the extent possible, further declines of the stock. This is to preserve the stock such that, should the prevailing conditions limiting the stock’s recovery change, the stock retains the potential to rebuild.

    4.2 Additional measurable objectives and timelines

    Under the PA framework, management actions must promote stock growth and removals from all fishing sources must be kept to the lowest possible level while the stock is in the critical zone, and there should be no tolerance for preventable decline.

    Table 4 provides an overview of the secondary rebuilding objectives for the NAFO Division 4T white hake stock, aimed at enabling DFO to monitor all sources of mortality, the impacts of implemented management measures, whether there is improvement in the stock status and the overall state of the ecosystem.

    Table 4. Additional measurable objectives and timelines aimed at rebuilding white hake, NAFO Division 4T stock.

    Secondary objectives

    1. Keep removals from all sources to the lowest possible level by introducing new and/or stricter management measures in all fisheries that intercept white hake.
    2. Monitor sources of fishing mortality and enforce compliance of current management measures.
    3. Advance current scientific knowledge in the fields of monitoring stock status, recruitment, environmental conditions, and those ecosystem factors that are likely to impact the stock’s recruitment, growth, habitat and health.

    5.0 Management measures aimed at achieving the objectives

    Multiple management measures are required to achieve the objectives identified in Table 4. These measures and expected outcomes are presented in Table 5. They are informed by the DFO Sustainable Fisheries Framework policies such as the:

    Since the white hake stock (NAFO Division 4T) is unlikely to rebuild under prevailing conditions (see section 3.0: Probable causes for the stock’s decline), the objectives are aimed at preserving the stock such that should the prevailing conditions limiting the stock’s recovery change, the stock retains the potential to rebuild.

    White hake is 1 of 3 groundfish stocks under moratorium with overlapping distributions and listed under schedule XI of the Fishery (General) Regulations. Therefore, the rebuilding plan management measures for white hake need to take into account the ones in the rebuilding plans for Atlantic cod and American plaice, which are also being caught as bycatch in remaining directed groundfish fisheries, for example:

    Cumulative effects associated with the implementation of multiple rebuilding plans may present challenges for other active groundfish fisheries, most notably to an emerging commercial redfish fishery in Unit 1, given its overlapping distribution with white hake and other stocks in the critical zone of the PA. Such potential impacts are expected to be monitored through current and newly implemented monitoring measures (see objective 2).

    Table 5. Summary of management measures aimed at achieving the rebuilding plan objectives for white hake in the southern Gulf of St. Lawrence, NAFO Division 4T. The year 2024 is considered to be year 1 of this rebuilding plan.

    Objective Management measure(s) Expected outcome Biology or environmental conditions taken into account
    1 – Keep removals from all sources to the lowest possible level by introducing new and/or stricter management measures in all fisheries that intercept white hake. Maintain the closure of the commercial directed fishery.
    The annual allocation of white hake in other commercial groundfish fisheries will be maintained at 30 t. This amount is deemed to be the lowest allocation level that would minimize impact on other commercial fisheries.
    Although the comprehensive review of the rebuilding plan is scheduled for 2028 (every 5 years), if after 2 years, the objective set in the plan in term of exceeding the TAC, additional adjustment measures may be evaluated and implemented before the next planned review.
    New management measures and/or adjustments to existing management measures already in place in other commercial groundfish fisheries may be introduced to further reduce interactions with NAFO Division 4T white hake. The establishment of a target depth range in specific fisheries or fishing areas, or the introduction of permanent or in-season spatial-temporal closures are examples of measures that could be implemented.
    Bycatch of white hake that can occur in the smelt, scallop and lobster fisheries cannot be retained, and therefore, must be returned to the water. Note: average bycatch landing from 2011 to 2020 was 11.5 t. As part of the bycatch protocol in place in other commercial groundfish fisheries; reducing the bycatch limit for white hake in 2028 to ensure consistency across all directed groundfish fisheries. Details on existing bycatch limits in other groundfish fisheries and the revised limits are presented in Annexes 1 and 2. When the bycatch limit is reached, the fishing area could be closed for a period of time or for the entire season.    		 Minimize fishing mortality to the lowest possible levels to preserve the stock such that if prevailing conditions change, it may be able to rebuild.
    The allocation would allow other directed groundfish fishing activities to occur (i.e., Atlantic halibut, Greenland halibut, witch flounder, redfish and other groundfish species), while reducing fishing mortality to the lowest possible level.    		 Based on the requirements stated in the PA framework for stock in the critical zone.
    2 – Monitor sources of fishing mortality and enforce compliance of current management measures. In 2024, implement or maintain 100 percent dockside monitoring in all commercial groundfish fisheries known to intercept white hake.
    In 2026, implement the use of VMS (Vessel Monitoring System) in all NAFO Division 4T groundfish fisheries, to monitor fishing effort and bycatch distribution.
    In 2025, initiate a pilot project to test the use of electronic monitoring tools (e.g., video monitoring) in a number of commercial groundfish fisheries.
    The recreational and FSC fisheries represent non-significant catches (no quantitative data, only qualitative), so no additional monitoring measures are being implemented at this time.    		 Dependable and timely data to locate and quantify catches from all fisheries which intercept white hake. Monitoring fishing activities and compliance of existing management measures.
    3 – Advance current scientific knowledge in the fields of monitoring stock status, recruitment, environmental conditions, and those ecosystem factors that are likely to impact the stock’s recruitment, growth, habitat and health. Continue the September annual RV survey, which is the primary data-source to estimate abundance distribution and indexes in interim years.
    Supplement RV survey data with DFO Science lead research projects and fishery dependent sources, such as:
    sentinel fishery,
    harvester’s logbooks,
    at-sea observer reports and
    VMS data. Continue research on ecosystem and species interactions, and natural mortality.
    Establish/update reference points.
    Note: the upper stock reference point would be developed by fishery managers informed by consultations with the fishery and other interests, with advice and input from Science.    		 Stock assessments, interim updates and research findings are peer-reviewed and published. Identify species distribution, and potential overlap between white hake and other commercially exploited species to minimize interactions.

    6.0 Socio-economic considerations

    While a summary analysis of the economic stock contribution is presented in section 1.6 of this document, this section provides a socio-economic analysis of the proposed management measures to the extent possible.

    The implementation of any new measures to further curtail and monitor the bycatch of white hake will have an impact on the harvesters currently engaging in the remaining directed commercial groundfish fisheries of the sGSL. However, since there is no reduction in annual bycatch allocation, impacts on commercial harvesters are not anticipated.

    There is considerable uncertainty related to the potential development of a new commercial fishery for Unit 1 redfish in the sGSL and the impact it could have on the 4T white hake stock. There is an overlapping spatial distribution for redfish and white hake stocks in the sGSL which will likely result in an increase in white hake bycatch if a new commercial redfish fishery is open. However, the scope, scale, spatio-temporal distribution, marketability, and opening of this fishery have not been determined, nor have any potential mitigation measures that could be imposed on the fishery in order to reduce its impact on white hake and other groundfish stocks.

    7.0 Method to track progress towards achieving the objectives

    Performance metrics provide DFO with a means to assess the progress of the rebuilding plan towards the plan’s objectives. For each objective, the following outlines how and when progress will be measured:

    Table 6. Summary of the performance metrics and frequency of measurement associated with each objective in this rebuilding plan.

    1. Objective: Keep removals from all sources to the lowest possible level by introducing new and/or stricter management measures in all fisheries that intercept white hake.
      • Metric to measure progress: Annual white hake bycatches do not exceed the allowed TAC of 30 t.
      • Frequency of measurement: Annually as part of the Gulf Region post-season review of all management activities and fisheries conducted in the sGSL (NAFO Division 4T).
    2. Objective: Monitor sources of fishing mortality and enforce compliance of current groundfish management measures.
      • Metric to measure progress: Qualitative assessment of the efficiency and efficacy of catch monitoring programs with the different fleets and harvesters.
      • Frequency of measurement: Annually as part of a review of all management activities and fisheries conducted in the sGSL (NAFO Divisions 4T) (Gulf Region – Annual post-season review).
    3. Objective: Advance current scientific knowledge in the fields of monitoring stock status, environmental conditions, and those ecosystem factors that are likely to impact the stock’s growth, habitat, and health.
      • Metric to measure progress: Conduct the September annual research vessel survey. Findings from science work published in CSAS research documents within the 5 years review cycle. Some results may also be published in specialized scientific journals.
      • Frequency of measurement: Regularly, as documents are peer-reviewed and published on the CSAS Website or in scientific journals.

    8.0 Periodic review of the rebuilding plan

    The department will engage stakeholders on any matter related to the implementation/review of the rebuilding plan through the established Gulf Groundfish Advisory Committee (GGAC) process. Outcomes from the application of this rebuilding plan will be monitored periodically, and a comprehensive review will be undertaken every 5 years, which corresponds to the science stock assessment frequency.

    The review of the plan will be based on the data gathered using the metrics identified in the Method to track progress towards achieving the objectives section of this plan. It will assess the progress of the implementation of management measures and evidence of their effectiveness, as well as the status of the stock and recent trends. In addition, the review will include opportunities for consultation with Indigenous groups and stakeholders on their views of the stock’s progress towards rebuilding.

    A report will be issued at the end of the review process that assesses progress toward each management objective against their timelines with accompanying evidence and may propose adjustments to the rebuilding plan if necessary to achieve the objectives.

    Stock rebuilding is not always a slow and steady, or even predictable process. Stocks may fluctuate and/or persist at low levels for years until conditions promote surplus production, resulting in rapid growth of the population. Thus, lack of progress towards rebuilding may not be an indication that the rebuilding plan’s objectives or management measures are insufficient or ineffective.

    9.0 References

    Benoît, H.P., and Swain, D.P. 2008. Impacts of environmental change and direct and indirect harvesting effects on the dynamics of a marine fish community. Can. J. Fish. Aquat. Sci. 65: 2088–2104. doi:10.1139/F08-112.

    Benoît, H.P., Swain, D.P., and Hammill, M.O. 2011a. A risk analysis of the potential effects of selective and non-selective reductions in grey seal abundance on the population status of two species at risk of extirpation, White Hake and winter skate in the southern Gulf of St. Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2011/033. iv + 30 p.

    Benoît, H.P., Swain, D.P., Bowen, W.D., Breed, G.A., Hammill, M.O., and Harvey, V. 2011b. Evaluating the potential for grey seal predation to explain elevated natural mortality in three fish species in the southern Gulf of St. Lawrence. Mar. Ecol. Progr. Ser. 442: 149-167.

    Chang, S., Morse, W. W., & Berrien, P. L. 1999. Essential fish habitat source document. White Hake, Urophycis tenuis, life history and habitat characteristics. NOAA Tech. Mem. NMFS-NE-136. 23 p.

    Chouinard, G.A., and Hurlbut, T.R. 2011. An atlas of the January distribution of selected marine fish species in the Cabot Strait from 1994 to 1997. Can. Tech. Rep. Fish. Aquat. Sci. 2967: viii + 94 p.

    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.

    Darbyson, E., and Benoît, H.P. 2003. An atlas of the seasonal distribution of marine fish and invertebrates in the southern Gulf of St. Lawrence. Can. Data Rep. Fish. Aquat. Sci. 1113: iii + 294p.

    Davis, A., Hanson, J.M., Watts, H., and MacPherson, H. 2004. Local ecological knowledge and marine fisheries research: the case of white hake (Urophycis tenuis) predation on juvenile American lobster (Homarus americanus). Can. J. Fish. Aquat. Sci. 61: 1191–1201.

    DFO, 2004. White Hake in the Southern Gulf of St. Lawrence (Div. 4T). DFO Can. Sci. Advis. Sec. Stock Status Rep. 2004/007.

    DFO. 2009. A Fisheries Decision-Making Framework Incorporating the Precautionary Approach (April, 2009).

    DFO. 2011. Impacts of Grey Seals on Fish Populations in Eastern Canada. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2010/071.

    DFO. 2013. Policy on Managing Bycatch (April, 2013).

    DFO. 2016. Recovery Potential Assessment for White Hake (Urophycis tenuis): Population of the Southern Gulf of St. Lawrence. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/034.

    DFO. 2019. Fishery Monitoring Policy (November, 2019).

    DFO. 2020. Updated indices of abundance to 2019 for Winter Flounder from NAFO Div. 4T, Witch Flounder from NAFO Divs. 4RST and White Hake from NAFO Div. 4T. DFO Can. Sci. Advis. Sec. Sci. Resp. 2020/008.

    DFO. 2021. Impact of an expanding Redfish (Sebastes spp.) fishery on southern Gulf of St. Lawrence White Hake (Urophycis tenuis). DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2021/033.

    DFO. 2022. Stock assessment of Northwest Atlantic grey seals (Halichoerus grypus) in Canada in 2021. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2022/018.

    Fahay, M.P., and Able, K.W. 1989. White Hake, Urophycis tenuis, in the Gulf of Maine: spawning seasonality, habitat use, and growth in young of the year and relationships to the Scotian Shelf population. Can. J. Zool. 67: 1715-1724.

    Hammill, M.O., Stenson, G.B., Swain, D.P., and Benoît, H.P. 2014. Feeding by grey seals on endangered stocks of Atlantic Cod and White Hake. ICES J. Mar. Sci. 71: 1332-1341.

    Hurlbut, T.R. 2012. Possible disappearance of a white hake (Urophycis tenuis) spawning component in Baie Verte (Northumberland Strait): Evidence from fixed station sampling in July 1985, July 1986, June 1994 and July 2001. DFO Can. Sci. Advis. Sec. Res. Doc. 2011/103. iv + 10 p.

    Rolland, N., McDermid, J.L., Swain, D.P., Senay, C. 2022. Impact of an expanding Redfish (Sebastes spp.) fishery on southern Gulf of St. Lawrence White Hake (Urophycis tenuis). DFO Can. Sci. Advis. Sec. Res. Doc. 2022/005. viii + 69 p.

    Swain, D.P. and Benoît, H.P. 2015. Extreme increases in natural mortality prevent recovery of collapsed fish populations in a Northwest Atlantic ecosystem. Mar. Ecol. Prog. Ser., 519: 165-182.

    Swain, D.P., Benoît, H.P., & Hammill, M.O. 2015. Spatial distribution of fishes in a northwest Atlantic ecosystem in relation to risk of predation by a marine mammal. J. Anim. Ecol. 84: 1286-1298.

    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.

    Swain, D.P., Savoie, L., and Cox, S.P. 2016. Recovery potential assessment of the Southern Gulf of St. Lawrence Designatable Unit of White Hake (Urophycis tenuisMitchill), January 2015. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/045. vii + 109 p.

    Swain, D.P., Ricard, D., Rolland, N., and Aubry, É. 2019. Assessment of the southern Gulf of St. Lawrence Atlantic Cod (Gadus morhua) stock of NAFO Div. 4T and 4Vn (November to April), March 2019. DFO Can. Sci. Advis. Sec. Res. Doc. 2019/038. iv + 105 p.

    Annex 1

    At-sea observer and dockside monitoring minimum requirements, and bycatch limits by fleet, fishing gear and target species in 2022-23

    Halibut: Fixed gear – NAFO Divisions 4RST

    Winter flounder: Fixed gear – NAFO Divisions 4RST

    Yellowtail flounder: Mobile gear – NAFO Division 4T

    Witch flounder: Mobile gear – NAFO Divisions 4RST

    Redfish (index fishery): Mobile gear – Unit 1 (4RST, 3Pn, 4Vn)

    * Stocks prescribed in the Fishery (General) Regulations (section 69) and thus are subject to section 6.2 of the Fisheries Act and regulatory requirements.
    1 Species not specified as bycatch in the conservation harvesting plan, but may be reported as “Other groundfish species” if caught.
    DMP: Dockside monitoring program.
    ITQ: Individual transferable quota.
    VMS: Vessel monitoring system.

    Annex 2

    White hake NAFO Division 4T key management measures until the next review of the rebuilding plan in 2028.

    Objective 1

    Keep removals from all sources to the lowest possible level by introducing new and/or stricter management measures in all fisheries that intercept white hake.

    In any year, if the objective set in the plan in term of bycatch level is exceeded, additional adjustment measures may be evaluated and implemented before the next planned review.

    Objective 2

    Monitor sources of fishing mortality and enforce compliance of current groundfish management measures.

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