Science Advisory Report  2013/045

2013 Assessment of 4VWX Herring

Summary

SW Nova Scotia / Bay of Fundy

• Landings for the 2010/2011 and 2011/2012 quota years were 50,010t and 47,614t against a Total Allowable Catch (TAC) of 50,000t each year for the SW Nova Scotia/Bay of Fundy component. Landings have tracked the TAC since 2002, with most of the quota being taken each year since 2002.  In 2010, as a result of an industry decision late in the season 9,466t of quota was left in the water. Since 2010 there have been self imposed measures by industry to monitor and regulate catches of fish less than 18cm.
• Acoustic survey catch at age had a broad age distribution of spawning fish from ages 3-11. There was a broader distribution of age-classes in the commercial catch at age than the acoustic survey catch at age. The proportion of fish at age 6 and older was 19% (2011) and 30% (2012) in the acoustic survey catch at age compared with 9% (2011) and 14% (2012) in the fishery.
• The overall acoustic biomass estimates (Scots Bay, Trinity Ledge and German Bank) increased in 2011 to 448,771t (44% over 2010) and further increased in 2012 to 476,026t (6% over 2011). This moves the overall acoustic biomass estimate to above the long term average (1999-2012).
• There has been a trend of declining mean weight at age. Declining trends in mean weight at age since the 1970s have reduced productivity of the stock.
• The three-year moving average for the acoustic survey estimate (Scots Bay and German Bank combined) in 2009 was calculated to be below the limit reference point by 5%. The three-year moving average increased to above the limit reference point in 2010 by 10%, in 2011 by 9% and in 2012 by 19%. The 2011 acoustic survey estimate increased to reach the long term average while the 2012 acoustic survey estimate increased to 7% above the long term average. The three-year moving average increased above the limit reference point in 2010 and changed very little in 2011 but then increased again in 2012.
• A harvest strategy which continues to exercise caution is appropriate.

Offshore Scotian Shelf Banks

• Since 1996, a fishery has taken place on feeding aggregations on the offshore banks of the Scotian Shelf, primarily in May and June, with catches ranging from 1,000 to 20,000t. In 2011, total landings were above average at 10,455t, down from 11,862t in 2010. In 2012, only 1,210t were landed from the offshore.
• No industry surveys were conducted on the offshore Scotian Shelf in 2011 or 2012.
• The industry is again encouraged to explore and undertake structured surveys of the offshore area.
• There was no new information and no reason to change the recommendation that the initial catch allocation for 2013 should not exceed 12,000t as described in the DFO management plan.

Coastal (South Shore, Eastern Shore and Cape Breton) Nova Scotia

• Landings and allocations in the Little Hope/Port Mouton area have decreased since 2009. In 2011, 2,564t were landed against an allocation of 2,094t and in 2012, 2,150t were landed against an allocation of 2,188t. Landings decreased from 6,045t in 2009 to 799t in 2012 in the Eastern Shore area while the allocation also decreased from 3,857t to 2,920t during the same time period.
• The survey biomass in the Halifax/Eastern shore area saw a large decrease in 2010 declining to 27.7kt. This trend continued into 2011 (5.5kt) and 2012 (3.7kt) to the lowest since surveys started and well below the recent five year average of 24.3kt.
• Collaborative surveys with industry have improved our knowledge of two areas (Little Hope/Port Mouton, Halifax/Eastern Shore), but there has been no increase in information from other areas. Surveying in the Glace Bay area concluded in 2011. It is again recommended that no coastal spawning group experience a large effort increase in new areas until enough information is available to evaluate the state of that spawning group. 
• It has been noted since 1997 that the status of herring in the Bras d’Or Lakes is cause for concern, but there has been no research or surveying in recent years. It is; therefore, appropriate to reiterate that no fishing should take place on this spawning component.
• Harvest levels from these areas use a five year average of recent catches and/or surveyed acoustic biomass to set initial targets.

SW New Brunswick Migrant Juvenile

• The southwest New Brunswick weir and shutoff fisheries have relied, for over a century, on the aggregation of juvenile herring (ages 1-3) near shore at the mouth of the Bay of Fundy. These fish are considered to be a mixture of juveniles, dominated by those originating from Northwest Atlantic Fisheries Organization (NAFO) Subarea 5 spawning components, and have, therefore, been excluded from the SW Nova Scotia/Bay of Fundy quota.
• Landings in New Brunswick weir and shut-off fishery were down dramatically from 10,958t in 2010, to 3,711t in 2011 and 504t in 2012. The 2012 catch is the lowest in the history of the fishery. It is notable that as recently as 2007 landings were 30,944t, the highest in nearly 20 years and higher than the long term average of 23,560t.
• Fish caught in the New Brunswick weir and shutoff fishery were mostly juveniles (54% at age 2 in 2011 and 80% at age 1 in 2012).
• The number of weirs with catches decreased in 2011 and 2012, with only 37 weirs reporting catches in 2011 and four weirs in 2012.
• The success of this passive fishery is historically unpredictable, and catches are extremely susceptible to many natural variables in addition to abundance.

This Science Advisory Report is from the March 26-27, 2013 Assessment of 4VWX Herring.  Additional publications from this process will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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