Science Advisory Report 2015/040
2015 Assessment of 4VWX Herring
SW Nova Scotia/Bay of Fundy
- Landings for the 2012/2013 and 2013/2014 quota years were 46,554t and 50,250t against a Total Allowable Catch (TAC) of 50,000t each year for the SW Nova Scotia/Bay of Fundy (SWNS/BoF) component.
- Landings have tracked the TAC since 2002, with most of the quota (and on occasion slightly above) being taken each year since 2002.
- Although there is uncertainty associated with the biomass estimates, longer term trends in biomass appear to be evident for the SWNS/BoF spawning component: a decreasing trend in the German Bank area from 1999 to present, and an increasing trend in the Scots Bay area since 2005.
- In 2012, a conservation limit reference point (LRP) for the SWNS/BoF herring spawning component (German Bank and Scots Bay) was identified as the 2005-2010 average acoustic survey biomass (371,067t), below which, the risk of serious harm is unacceptable (Clark et al. 2012).
- The three-year moving average increased above the LRP in 2011 and changed very little in 2012. Since 2012, the three-year moving biomass average has been increasing slightly each year. Biomass estimates have fluctuated about the LRP since 2010. Confidence intervals include the LRP in three of the last four years, the exception being 2012 when the confidence interval was above the LRP.
- The biomass of spawning fish estimated to be on Trinity Ledge from 2012 to 2014 is low relative to values observed in the early 2000s. Fishing during the spawning season on Trinity Ledge has the potential to jeopardize the persistence of this spawning unit.
- The broad range of ages observed in the commercial landings indicates that the conservation objective to maintain a broad range of ages is generally being met.
- There has been a trend of declining mean weight at age. Declining trends in commercial mean weight at age since the 1970s have reduced productivity of the stock.
- A harvest strategy, which continues to exercise caution, is appropriate.
Offshore Scotian Shelf Banks
- Since 1996, a fishery has occurred on feeding aggregations on the offshore banks, primarily in May and June, with landings ranging from 20,261t in 1997 to 58t in 2014. Landings from 2012 to 2014 were amongst the lowest in the time series.
- No industry surveys were conducted on the offshore Scotian Shelf in 2013 or 2014. In the fall of 2014, industry conducted searches in the offshore but failed to find any spawning aggregations.
- In the absence of recent information about stock status there is no basis for evaluating the current 12,000t catch allocation. The industry is again encouraged to explore and undertake structured surveys of the offshore area.
Coastal (South Shore, Eastern Shore and Cape Breton) Nova Scotia
- From 2009 to 2014, landings in the Little Hope/Port Mouton area have ranged between 2,150t and 3,731t, and have been near or above the allocation.
- From 2009 to 2014, landings in the Eastern Shore area have ranged between 771t and 6,045t, and are generally below the allocation.
- Landings were minimal for Glace Bay with 2t in 2013 and 1t in 2014.
- The Bras d’Or Lakes area remained closed to herring fishing. It has been noted since 1997 that the status of herring in the Bras d’Or Lakes is cause for concern. In the absence of current abundance information the Bras d’Or Lakes should remain closed.
- Individual spawning groups within the coastal component are considered vulnerable to fishing because of their relatively small size (biomass) and proximity to shore. For this reason, a large effort increase in new areas has a potential to markedly reduce abundance in the absence of information about the status of the specific spawning group.
- With the exception of the four main areas, the size of various additional spawning groups and landings from these groups are poorly documented. In addition to the traditional bait and personal-use fisheries, directed roe fisheries have occurred on several spawning grounds since 1996.
Southwest 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.
- Fish caught in the New Brunswick weir and shutoff fishery were mostly juveniles (93% and 96% at either age 1 or age 2 in 2013 and 2014, respectively).
- For the time series presented, current landings are at or near the lowest observed. In 2012, the number of weirs with landings was at a historical low, but subsequently increased to 49 in 2013. In 2014, the number of weirs with landings again decreased to 26.
- Abundance of herring available to the weirs is unknown.
- The primary sources of information for assessing this component are the landings, which have declined markedly from the 1980s to present. The landings time series for this fishery may not be indicative of abundance because catches are extremely susceptible to many factors in addition to abundance, including effort.
This Science Advisory Report is from the March 25-26, 2015, 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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