Science Advisory Report  2008/019

Assessment of Herring in the Southern Gulf of St. Lawrence (NAFO Div. 4T)

Summary

Spring Spawner Component

1. Reported 2007 landings of the spring spawner component in both the spring and the fall fisheries were 3,789 t against the spring spawner TAC of 5,000 t.
2. Mean inshore gillnet catch rate in 2007 remains one of the lowest in the series that starts in 1990.
3. The 2007 acoustic survey index of abundance was the lowest in the series that starts in 1994.
4. The 2007 index from the opinions of harvesters contacted in the telephone survey on the abundance of spring herring was the lowest in the time series that starts in 1987.
5. The abundances of year-classes after 1991 were average or below average.
6. Age 4-10 spawning biomass is estimated at 20,500 t for the beginning of 2008.
7. The estimated exploitation rate in 2006 and 2007 was below the reference level.
8. Overall spawning stock biomass has declined since 1995 and remains at a low level since 2004.
9. The current estimate of age 4-10 biomass (20,500 t) is below the limit reference point (LRP). At this level of biomass, the precautionary approach requires that removals from the stock should be kept to the lowest level possible.
10. Even in the absence of any removals of the spring spawning component, there is a 50% probability that the biomass in 2009 will be below the limit reference level of 22,000 t. Catch options less than 1,500 t would provide a low probability (<25%) of further decline in biomass.

Fall Spawner Component

1. Reported 2007 landings of the fall spawner component in both the spring and the fall fisheries were 47,621 t against the fall spawner TAC of 68,800 t.
2. Mean inshore gillnet catch rates in 2007 were lower than 2006 but remain among the highest in the time series that starts in 1978.
3. The 2007 index from the opinions of harvesters contacted in the telephone survey on the abundance of fall herring has been increasing since 1987.
4. The 1998 and 2000 year-classes are above average.
5. Overall, the stock remains at a high level of abundance relative to the late 1970’s and early 1980’s.
6. The 2008 beginning-of-year spawning stock biomass is estimated to be about 302,000 t, well above the upper stock reference (USR) biomass level of 172,000 t.
7. The exploitation rate in 2007 was below the F_0.1 reference level.
8. For 2008, a catch option of 69,000 t corresponds to a 50% chance that F would be above the F_0.1 removal rate. On the other hand, there is a low probability (< 25%) of a decline in biomass for catch options less than 50,000 t.

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