Science Advisory Report  2010/038

2010 Assessment of 4VWX Herring

Summary

SW Nova Scotia Bay of Fundy

• Landings in 2008/09 were 54,113t against a Total Allowable Catch (TAC) of 55,000t for the Southwest (SW) Nova Scotia/Bay of Fundy component. Landings have tracked the TAC in recent years, with most of the quota being taken each year since 2002.
• In 2009, the fishery catch at age composition was comprised of 45% fish at 2 years of age, 20% at age 3, 24% age 4, and 11% at older ages. The proportion of the catch older than age 5 decreased from 17% in 2008 to 7% in 2009. This decrease of older/larger fish in the catch was due to the high proportion of 2 year olds (potentially indicating a strong 2007 year class).
• Acoustic biomass estimates increased for each of the major survey areas (from 221,001t in 2008 to 377,000t in 2009). Taking into consideration confidence intervals, overall spawning stock biomass (SSB) for the past 5 years has been steady, at a lower level than in the 1999-2004 period. SSB for Trinity is extremely low.
• Fishing mortality could not be determined. Relative exploitation rates based on acoustic SSB estimates with catch decreased in 2009.
• This assessment indicates improvements from the low level of the resource noted in the previous assessment, e.g., SSB estimated from the acoustic surveys is approaching the series average (1999-2008).
• A harvest strategy that exercises continued caution to facilitate further rebuilding is recommended. Catch levels that remain near the current status quo would help to reduce risks related to uncertainties in estimating SSB, recruitment, and the exploitation rate for this stock.

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 1,000t to 20,000t. Total landings were above average at 9,088t in 2009, up from 920t in 2008,
• There is little new information to add and no reason to change the previous recommendation that the initial catch allocation for 2010 should not exceed the 12,000t as described in the DFO management plan.
• The industry has been encouraged to explore and undertake structured surveys of the offshore area.

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

• The landings in the roe gillnet fisheries along the coast of Nova Scotia increased from 3,500t in 2008 to 9,800t in 2009.
• In 2009 there was a large increase in the surveyed biomass in the Little Hope/Port Mouton area from 14,500t to 36,600t and is now well above the recent 5 year average of 24,500t. The surveyed biomass in the Halifax/Eastern shore area saw a slight increase in 2008 and a large increase in 2009 from 30,300t to 54,200t, which is above the recent 5 year average SSB of 43,700t observed for this area.
• Collaborative research with industry has improved knowledge of three areas (Little Hope/Port Mouton, Halifax/Eastern Shore and Glace Bay), but there has been no increase in knowledge of other areas. It is again recommended that no coastal spawning groups experience a large effort increase in new areas until enough information is available to evaluate the state of that spawning group. 
• Harvest levels from these areas use a five year average of recent catches and/or surveyed acoustic biomass with the Calibration Integration Factor (CIF) to set initial targets. It is recommended that the “survey, assess, then fish” protocol should continue to be applied.

SW New Brunswick Migrant Juvenile

• SW New Brunswick migrant juveniles have been 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 the 2009 New Brunswick weir and shut-off fishery were 4,000t, the lowest catch since 1963 and well below the long term average. Two years previous, this fishery landed 30,900t, which was higher than the long term average of 23,560t.
• The age distribution of fish caught in the 2009 New Brunswick weir and shutoff fishery indicated mostly juveniles, with 86% at age 2.
• The number of weirs with catches decreased in the 2009 season, but effort remained similar.
• The success of this passive fishery is historically unpredictable, and catches are inherently susceptible to many natural variables in addition to abundance.

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