Canadian Atlantic Herring (Clupea harengus) -
SWNS Rebuilding Plan - Atlantic Canada - 2013

herring

FORWARD

This document constitutes the Rebuilding Plan for the Southwest Nova Scotia / Bay of Fundy (SWNS/BoF) spawning component of the Atlantic Herring fishery in the Maritimes Region.

Southwest Nova Scotia / Bay of Fundy Herring Spawning Component Rebuilding Plan with Limit Reference Point

1.0 Overview of the Fishery

The herring fishery for the Southwest Nova Scotia / Bay of Fundy (SWNS/BoF) spawning component is diverse. It includes licences for Food, Social and Ceremonial purposes, herring transport licences and commercial, recreational, and bait fisheries. The largest component is the commercial fishery pursued by purse seiners, weir, gillnets and trap nets. Most fishing takes place on dense summer feeding, over wintering, and spawning aggregations. The commercial fishery is based on a Total Allowable Catch (TAC) system, with the mobile gear sector receiving access to approximately 80% of the annual TAC. This allocation is then managed via an Individual Transferable Quota (ITQ) system which is set based on a percentage share established for each licence holder. The fixed gear sector fish their portion (approximately 20%) of the TAC competitively.

2.0 Stock Assessment

In 2011, the Atlantic Herring stock assessment framework was finalized and provides the basis for how the stock status will be assessed. The last assessment of the stock took place in April 2011 using the new framework. In February, 2012, a Regional Advisory Process (RAP) was held to examine available data to determine candidates for a limit reference point (LRP) consistent with the Precautionary Approach Policy for the SWNS/BoF Herring Fishery.

Precautionary Approach - Limit Reference Point

The February RAP determined that the 2005 to 2010 average acoustic survey value was the conservation limit reference point for SWNS/BoF herring (German Bank and Scots Bay). The limit reference point (LRP) marks the boundary between the cautious and critical zones. When a fish stock level falls below this point, there is a high probability that its productivity will be impaired and that serious harm will occur (Fishery Decision-Making Framework Incorporating the Precautionary Approach). The limit reference point was established based on the best available scientific information.

The stability at the 2005-2010 level supports its selection as the LRP and provides data from which to select a point, below which, the risk of serious harm is unacceptable. Other considerations that lead to the selection of this point relate to the objective of avoiding negative impacts to the ecosystem and long-term loss of fishing opportunities. Ecosystem considerations include herring's role as a forage fish, and long-term loss of fishing opportunities in the case of stock collapse and possible decades required for recovery to occur.

It was determined that a three year running average would be used to determine the state of the SWNS/BoF herring (German Bank and Scots Bay) in relation to the LRP because of the variability in the annual acoustic point estimates. Given the life history characteristics of herring, the three year running average is more appropriate for detecting the trend and would smooth out inter-annual variability.

Stock Assessment

A framework assessment for the SWNS/BoF herring spawning component concluded in January, 2011. As a result of difficulties using an analytical framework to provide estimates of current stock size, an assessment methodology was developed that would partly rely on the acoustic approach additive model and on a series of sign-of-change indicators chosen to provide insight on stock status and advice for the management of the fishery.

  • Acoustic survey biomass trends
  • Fishermen input
  • Numbers or proportion at age in catch
  • Trends in exploitation rates from survey
  • Mortality rate trends based on age composition, F=Z-M

The most recent assessment (DFO 2011) of the stock indicated stability at a lower level with little or no signs of improvement. Furthermore, the lack of rebuilding, despite reduced catch levels in recent years, was said to be cause for concern. It recommended a harvest strategy that exercises caution, including additional restrictions in small fish removals was appropriate.

The Role of Secondary Indicators

Secondary indicators are chosen because they provide valuable information regarding the status of the stock beyond the biomass indicator and provide insight on the productivity of the resource. Secondary indicators for SWNS/BoF were reviewed at framework and accepted in addition to the previously developed indicators for spawning grounds. It is likely that there will be conflicting signals amongst the secondary indicators and it may not always be possible to conclusively determine the overall zone the stock is in. Interpretation on the overall zone will require professional judgment.

Broad age distribution and composition

The main objective of the IFMP is the conservation of the herring resource and the preservation of its spawning components. It is desirable to have a broad age distribution and composition because it makes the population more resilient. Egg production increases with age and weight of herring therefore it is important to maintain broad age compositions in the population. When population structure has remained largely intact, rebuilding may be achieved within a relatively short time. In contrast when age and contingent structure has been damaged, substantially recovery time exceeded a decade or more (Petitgas et al, 2010).

The catch of herring in this area is extremely well sampled. The age composition of the catch is calculated from these samples annually. A broad age distribution (having all ages represented in the catch) and composition (having sufficient numbers of each age) is desirable for both the catch and the survey biomass.

Age distribution was chosen as an indicator because it is sensitive to exploitation. For example, a lack of older fish in the catch can be indicative of high total mortality. Information on age distribution and composition is readily available. This is a common metric in fisheries stock assessment.

Spawning ground spatial and temporal objectives

The persistence of the length of time for spawning, the spatial and temporal diversity and the number of spawning grounds have historically been primary objectives for the management of this fishery. The objective is to maintain the reproductive capacity of herring in each management unit.

There are four main documented spawning grounds (Scots Bay, German Bank, Trinity Ledge and Seal Island). Each of the spawning components should be evaluated individually and comprehensively as one unit.

This was chosen as an indicator because when the stock is in a low abundance situation, spatial distribution for herring can be contracted to the spawning and feeding areas (Ulltang, 1980; Overholtz, 2002; Melvin and Stephenson, 2007; Dickey-Collas et al 2010). This indicator is also sensitive to exploitation and the information is readily available. If there is a long spawning time over the traditional areas, it makes the population more resilient.

3.0 Management Issues

Stock Status

The status of herring stocks in the SWNS/BoF spawning component have been of concern for a decade or more and stock status reports have indicated the need for rebuilding since at least 2001 (DFO 2011, 2012). The most recent assessment (DFO 2011) of the stock utilized the framework methodology and indicated:

..stability at a lower level with little or no signs of improvement. The lack of rebuilding, despite reduced catch levels in recent years is cause for concern. A harvest strategy that exercises caution, including additional restrictions in small fish removals is appropriate.

The position of the SWNS/BoF component in relation to the LRP was determined (DFO 2012). It is positioned lower in the cautious zone at a stable level (DFO 2012).

Account for all Mortality

The FRCC report stated that landings of herring for commercial sale are generally considered to be well documented, but there is concern about the unrecorded landings of herring used for bait. In the Maritimes Region there are close to 1200 bait licence holders and the amount of herring being landed for bait is unknown. The number of bait licences actively used in the SWNS/BoF area is unknown; however, the FRCC report cautioned that the danger of these unreported landings is greater in areas where there is a combination of poor stocks and a high number of active lobster and snow crab harvesters.

Compliance

Compliance with catch reporting is essential for proper management of the herring stock. In investigations by Fisheries Officers during the past five years, there have been instances of non-compliance in the form of reporting catches lower than the actual harvest. Both Industry and the Department agree to consider additional ways to evaluate compliance levels and take action as appropriate.

4.0 Objectives

The purpose of this document is to set out the objectives and associated strategies, tactics, reference points and management decision rules for the SWNS/BoF spawning component.

There are five overarching objectives that guide fisheries management planning in the Maritimes region. They are guided by the principle that the fishery is a common property resource to be managed for the benefit of all Canadians, consistent with conservation objectives, the constitutional protection afforded aboriginal and treaty rights, and the relative contributions that various uses of the resource make to Canadian society, including socio-economic benefits to communities.

The conservation objectives are those from the Maritimes region’s framework for an ecosystem approach to management (EAM framework). They require consideration of the impact of the fishery not only on the target species but also on non-target species and habitat.

Productivity of the herring resource is important and is a focus of this rebuilding plan.

  • Conservation Objectives
    1. Productivity: do not cause unacceptable reduction in productivity so that components can play their role in the functioning of the ecosystem.
    2. Biodiversity: do not cause unacceptable reduction in biodiversity in order to preserve the structure and natural resilience of the ecosystem.
    3. Habitat: do not cause unacceptable modification to habitat in order to safeguard both physical and chemical properties of the ecosystem.
  • Social, Cultural and Economic Objectives
    1. Culture and sustenance: respect aboriginal and treaty rights to fish.
    2. Prosperity: help create the circumstances for economically prosperous fisheries.

The social, cultural and economic objectives reflect the aboriginal right to fish for food, social and ceremonial purposes. They also recognize the economic contribution that the fishing industry makes to Canadian businesses and many coastal communities. Ultimately, the economic viability of fisheries depends on the industry itself. However, the department is committed to managing the fisheries in a manner that helps its members be economically successful while using the ocean’s resources in an environmentally sustainable manner.

  • Specific short term objectives of the rebuilding plan:
    • to rebuild the herring resource to an interim target of the 2001-2004 SSB level;
    • have a statistically significant positive trajectory in the reference point indicator;
    • limit small fish removals to increase productivity of the resource;
    • to maintain spatial and temporal objectives related to spawning grounds.
  • Specific long term objectives of the rebuilding plan:
    • rebuild the herring resource to the healthy zone;
    • improve the size & age distribution across the population; and
    • improve upon the spatial, temporal and biomass objectives related to spawning grounds in spawning locations.

5.0 Strategies and Tactics

This section presents the strategies and tactics being used in this fishery to achieve the objectives outlined above. Table 1 outlines the strategies and tactics, incorporating the limit reference point, which are applied to achieve the objectives for the stock.

Limit reference point (LRP) = 1.0

In the following table, characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.

Table 1: Strategies and Tactics for SWNS/BoF Atlantic Herring Spawning Component.
STRATEGIES TACTICS
Productivity
Keep fishing mortality of Southwest Nova Scotia / Bay of Fundy Herring moderate by using the following references and risk tolerances:

  • When the reference point is in the Healthy Zone, the TAC may be set to be tolerant of normal stock fluctuations.
  • Management actions should react to a declining trend that approaches the Health / Cautious Zone boundary. Risk tolerance for preventable decline – moderate (if low in zone) to neutral
  • When the reference point is in the Cautions Zone, The management response will vary depending on location of the stock within the Cautious Zone, whether the stock is increasing or decreasing, and indications from secondary indicators. The TAC should be set to mitigate declines and promote positive change in spawning stock biomass (SSB) over a reasonable time frame. It is required that fishing mortality will decline as the stock progresses lower into the Cautious Zone.
  • When the reference point is below the limit reference point (LRP), the harvest strategy is to be results-driven. Rebuilding to a level above the LRP should be achieved in a reasonable timeframe (6 to 8 years - 1.5 to 2 generations) with a high degree of probability. The TAC should be set with a very low risk of biomass decline.
  • Total Allowable Catch
  • Size Restrictions
  • Spatial / Temporal Closures
Maintain biomass of each spawning component.
  • Total Allowable Catch
  • Spatial / Temporal Closures
Maintain broad age composition and distribution (catch and survey).
  • Total Allowable Catch
  • Size restrictions
  • Spatial / Temporal Closures
Maintain spatial and temporal diversity of Spawning grounds (long spawning period for each component, maintain number of spawning components)
  • Total Allowable Catch
  • Size restrictions
  • Spatial / Temporal Closures
Biodiversity
Control unintended incidental mortality for all non-retained species.
  • Mandatory release
  • Avoidance
Control unintended incidental mortality for spotted wolfish, Northern wolfish and white shark.
  • Mandatory release
Habitat
Manage area disturbed of habitat.
  • N/A
Culture and Sustenance
Provide access for food, social and ceremonial purposes.
  • Issue food, social and ceremonial licences as required
Prosperity
Limit inflexibility in policy and licensing among individual enterprises/licence holders.
  • Exempted fleet licences
  • Substitute operators/ Designated operators
  • ITQs – no concentration limit
Minimize instability in access to resources and allocations.
  • ITQs,
  • Annual TAC variation
Limit inability for self-adjustment to overcapacity relative to resource availability.
  • ITQs
  • Limited entry
Support certification for sustainability.
  • Provision of data, where available

6.0 Monitoring, Evaluation and Performance Review

To ensure effective management of fisheries, regular reviews of management measures are required. There are two forums through which this takes place for the SWNS/BoF Herring fishery: the Regional Advisory Process and the Scotia-Fundy Herring Advisory Committee. This Rebuilding Plan will be reviewed at least every two years, either as part of these forums or as a separate undertaking.

7.0 Plan Enhancement

Based on the observed change in the SSB and other variables included in this plan, modifications to the plan may be necessary. These will be discussed when the plan is reviewed.

8.0 Management Measures

The status of the SWNS/BoF Atlantic Herring Spawning component was determined to be stable, albeit low in the Cautious Zone (DFO 2012). Guidance from the Precautionary Approach Policy states that management actions must encourage stock growth in the short term. Risk tolerance for preventable decline is low.

Reducing mortality to encourage stock growth is achieved via the tactics outlined in Table 1. Total Allowable Catch (TAC), size restrictions and spatial and temporal closures are the tactics available to realize this goal. Specifically, the following management measures for the seiner fleet will be put in place (or continued) for the 2011/2012 and 2012/2013 seasons. These will be in addition to the Conservation Harvesting Plan (Annex I). Also, in the event of any conflict between these measures and the Conservation Harvesting Plan (Annex I), these measures will take priority.

  1. Minimum fish length of 18 cm (tip to tip); there will be a 25% tolerance by count.
  2. October 15 to November 30 quota of 2,000mt
  3. No fishing in December
  4. January quota of 500mt
  5. No fishing in February, March or April
  6. May quota of 1,500mt
  7. Summer juvenile fish (fish less than 23 cm in length) quota of 14,000mt. Of this quota, 12,000mt will be available from June 1 to September 15 and 2000mt from September 16 to October 14, with rollover of uncaught quota from the first to second time period.
  8. Scots Bay quota of 5,000mt.
  9. 5 day fishing week in Scots Bay, and a 5 day fishing week in the German Survey Box from August 15 to September 30. Closure in both areas to be from noon Friday to noon Sunday. With respect to the German Survey Box, fishing Friday will be allowed if there has been no fishing during two nights of the that week, and fishing on Friday and Saturday will be allowed if there has been no fishing during three nights of the that week.
  10. Chedabucto Bay will follow the measures in Annex 1 and not be affected by any of these additional measures. Also, Chebucto Head (off Halifax) will not be affected by any of these additional measures.

Together with the TAC, these measures will address the short and long term objectives set out in this Plan. Specifically, the sub-allocations and closures represent controls on the catch, which will enhance the rebuilding of the SSB. The minimum fish length together with the juvenile allocations will limit the removals of small fish, an important Tactic related to maintaining productivity of the stock. The 18 cm minimum fish length was implemented in 2011 (increased from a 15 cm minimum fish length for 2010), and resulted in an estimated 40% reduction in the total number of fish removed in 2011 compared to 2010. Rebuilding the SSB and limiting the removals of small fish will maintain the spatial and temporal objectives with respect to the spawning grounds and improve catch at age. They will also increase the chances for recruitment success.

The TAC has been 50000-55000 mt since 2005. An improvement in the stock status has so far not been realized with these lower level harvests. Following the guidance from the PA Policy, management actions must encourage stock growth in in the short term, and the risk tolerance for decline is low. As the recent harvest levels have not resulted in a rebuilding of the stock, further reduction of fishing mortality using a lower TAC may be necessary should the above management measures not lead to a rebuilding of the stock in the short term.

An increase in the TAC may be considered if evidence of an upward trend (at least two consecutive years) of the lower confidence interval of the biomass indicators are observed, accompanied by improvements in the secondary indicators. If further decline is observed management action compliant with the PA Policy will be taken. Further decline would be a declining trend in biomass indicators (at least two consecutive years) and/or deterioration in secondary indicators.

References

DFO. 2011. 2011 Assessment of 4VWX Herring. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2011/046.

DFO. 2012. Reference points consistent with the precautionary approach for a variety of stocks DFO in the Maritimes Region. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2012/035.

Dickey-Collas, M., Nash, R. D. M., Brunel, T., van Damme, C. J. G., Marshall, C. T., Payne, M. R., Corten, A., Geffen, A. J., Peck, M. A., Hatfield, E. M. C., Hintzen, N. T., Enberg, K., Kell, L. T., and Simmonds, E. J. 2010. Lessons learned from stock collapse and recovery of North Sea herring: a review. – ICES Journal of Marine Science, 67: 1875–1886.

Melvin, G. D., and Stephenson, R. L. 2007. The dynamics of a recovering fish stock: Georges Bank herring – ICES Journal of Marine Science, 64, 69–82.

Overholtz, W. J., 2002. The Gulf of Maine-Georges Bank Atlantic herring (Clupea harengus): spatial pattern analysis of the collapse and recovery of a large marine fish complex, Fisheries Research, Volume 57, Issue 3, September 2002, Pages 237-254.

Petitgas, P., Secor, D. H., McQuinn, I., Huse, G., and Lo, N. 2010. Stock collapses and their recovery: mechanisms that establish and maintain life-cycle closure in space and time. – ICES Journal of Marine Science, 67: 1841–1848.

Ulltang. O. 1980. Factors Affecting the Reaction of Pelagic Fish Stocks to Exploitation and Requiring a New Approach to Assessment and Management. Rapp. P.-v. Reun. Cons. Int. Explor. Mer, 177: 49-504.

ANNEX I

SOUTHWEST NOVA SCOTIA / BAY OF FUNDY (4WX) SPAWNING COMPONENT HARVESTING PLAN

4WX herring fisheries are predominantly based on fish from the major spawning areas off Southwest Nova Scotia (SWNS), which comprises the Bay of Fundy spawning component (4WX and a portion of 5Y) stock complex. This area also contains migrants from the Gulf of Maine and discrete localized herring spawning groups along the Atlantic coast of Nova Scotia.

The largest portion of the catch is taken by the 12 vessel active mobile purse seine fleet fishing 40 licences. In recent years, there has been increased interest in other herring stocks including the Outer Banks of the Scotian Shelf and Georges Bank.

  1. Within SWNS / Bay of Fundy spawning component framework of the SFHAC, an industry co-chaired, DFO/Industry Monitoring Working Group will address in-season issues including the fishing of spawning aggregations and new/or developing herring fisheries.

    The Purse Seine Industry Monitoring Working Group (MWG) is composed of representatives of both sectors of the mobile gear industry (mobile gear, and processors). This committee operates in accordance with the Terms of Reference as agreed by DFO.
     
  2. The fishing seasons are as follows:
    1. SWNS/Bay of Fundy spawning component (HFAs 20 West of Baccaro Point line, 21, and 22) – October 15 to October 14
    2. Chedabucto Bay (HFA 19 and HFA 18 north to Scaterie Island line) – November 1 to March 1
      • November 1 to December 31 outside the Green Island line
      • January 1 to March 1 inside the Green Island line
         
  3. All mobile and fixed gear operate with Conditions of Licence requiring reporting and monitoring of landings in accordance with the provisions of an industry-funded Dockside Monitoring Program.
     
  4. Prior to departing to fish all mobile gear herring fishing vessels must register and receive confirmation from a DFO designated or Certified Dockside Monitoring Company as a condition of licence.
     
  5. The 80/20 sharing formula of the SWNS / Bay of Fundy spawning component removal level between seiners and fixed gear remains in effect for this Plan except as modified. The one midwater trawl license HER 00012 quota is 1% of the TAC. The 1% is deducted prior to the 80/20 sharing of the balance between the mobile and fixed gear sectors. In the event that the quota associated with the mid water trawl licence is transferred, as provided for in Transfer System noted below, not more than 80% may be transferred to the mobile sector while 20% will be added to the fixed gear quota.
     
  6. The fixed gear quota will be reviewed on September 1, September 15 and October 1 each year to maximize the economic benefit from the resource. Depending upon fixed gear performance, adjustments to the purse seine allocation levels can occur.

    If, following an allocation adjustment to the mobile fleet on October 1, the fixed gear fleet starts having significant removal levels of herring, the mobile fleet will cease fishing the reallocation portion until removal levels are adjusted against the overall quota.
     
  7. Purse seiners are allocated a specific vessel percentage allocation of the mobile gear share of the SWNS / Bay of Fundy spawning component quota as detailed in the Mobile Gear Shares SWNS / Bay of Fundy Spawning Component Table.
     
  8. The quota of 4WX herring to be fished during the winter (i.e., Chedabucto Bay November 1 – March 1) fishery on over wintering SWNS / Bay of Fundy spawning component stock will be limited to 20% of the previous year’s purse seine SWNS / Bay of Fundy spawning component quota.
     
  9. The purse seine fleet is authorized to participate in a Transfer System (internal to the purse seine fleet) in accordance with the following conditions:
    • transfers may be temporary or permanent;
    • the unit of transfer is tonnes;
    • there will be no cap on transfers;
    • transfers will be permitted to occur at any time subject to receipt of the appropriate authorizing signatures from both parties;
    • no requirement to retire the licence if quota reduced to zero (licence fees for licences with zero quota will be minimal);
    • temporary transfers will be permitted to occur up to four weeks after the close (October 14) of the SWNS / Bay of Fundy spawning component season.
       
  10. The winter (January 1 - February 28) Bay of Fundy (HFA 20 west of Baccaro and 21) purse seine reference figure of 6,000t is an estimated catch from the area and may be increased by transfer from the summer fishery. Similarly, any unused maybe transferred to the summer quota.
     
  11. The Chedabucto Bay fishery will be managed in accordance with Decision Rules for Managing Overwintering Fisheries.
     
  12. Target catch levels for individual SWNS / Bay of Fundy spawning component areas are premised on the in-season review process involving industry-funded surveying and assessment by DFO Science personnel, followed by fishing of up to 20% of the observed spawning aggregation. This process has become known as the “survey, assess, and then fish protocol”. The fishery may also be monitored through the use of observers.
     
  13. The Trinity Ledge area will remain closed to all herring fishing throughout the spawning season (approx. August 15 -September 15). This closure may be adjusted to protect spawning on Trinity Ledge. DFO may permit a limited fishery following application of the survey, assess, and then fish protocol.
     
  14. Waters west of a line from Gannet Rock Light to Split Rock (as outlined in Schedule VIII of the Atlantic Fishery Regulations, 1985) are closed to herring fishing with mobile gear from March 1 to October 1.

    Opening may be delayed via variation order for up to two (2) weeks if weirs are still operational and are retaining/catching herring. This would be decided in consultation with DFO, Connors Bros., and weir and mobile industry representatives.
     
  15. A five-day-per-week fishery for mobile gear fishing SWNS / Bay of Fundy spawning component will be put into effect if consensus is achieved among the MWG Committee. If implemented, the weekend closure would be in effect each Friday at 12:00 hours through to 12:00 hours each Sunday between August 15 and October 1.
     
  16. Requests for over-the-side sales (OSS) allocations can only be considered with industry agreement and in the context of the provisions of the Direct Sales Policy. Requests will be dealt with in a timely fashion.
SWNS / Bay of Fundy Spawning Component Quotas and Shares
  Share
Total Allowable Catch
October 15 to October 14
TAC
Mobile Gear:  
Mid water Trawl (HFA 20, 21)
January 1 to April 15
1% of TAC
  Balance
Total Purse seine (HFA 18, 19, 20, 21, 22) 80% of Balance
Winter Quota (HFA 20 & 21)
January 1 to February 28
Note: Winter reference figure
Not more than 500t of the winter quota may be taken from a line drawn due east from Bliss Island Light, Charlotte County, N.B. Currently under review3/09/03)
6,000t  
Chedabucto Bay
(HFA 19 & HFA 18 to Scaterie Island line)
November 1 to December 31 outside the Green Island line
January 1 to March 1 inside the Green Island line
20% of previous year Purse seine quota  
Fixed Gear:  
Gillnets, Traps and Weirs adjacent to Nova Scotia and West of Baccaro Point in HFA 20 20% of Balance
  1. For conservation reasons, purse seine licences that exceed their ITQ four weeks after the close of the 4WX season will be subject to quota reconciliation on a one for one basis up to 100t. This will be deducted from the individual licence holder’s quota in the following year. Exceeding 100 mt may be subject to further action.
     
  2. All purse seine licence holders will purchase and install a Vessel Monitoring System (VMS or “black box”) by May 2004.
     
  3. Any proposed vessel replacement greater than 125 ft. LOA or greater than 1500 BHP is required to be presented to the Herring Purse Seine Monitoring Committee for review and recommendation.

ANNEX II

ADDITIONAL CONSERVATION OBJECTIVES

Specific conservation objectives were reviewed and developed by the Scotia-Fundy Herring Advisory Committee in 1997. Three objectives and a number of targets within those objectives were defined:

  1. To maintain the reproductive capacity of herring in each management unit:
    • persistence of all spawning components in the management unit;
    • maintain biomass of each spawning component above a minimum threshold;
    • maintain a broad age composition for each spawning component; and
    • maintain a long spawning period for each spawning component.
  2. To prevent growth overfishing:
    • continue to strive for fishing mortality at or below F0.1.
  3. To maintain ecosystem integrity/ecological relationships (“ecosystem balance”): Herring is prominent in the diet of many fish, birds and marine mammals and should be managed with these interactions in mind. Specific targets include:
    • maintain spatial and temporal diversity of spawning
    • maintain herring biomass at moderate to high levels