The recruitment of the North Sea herring stock has been low since the good 2000 year class. ICES classifies the stock as being at risk of having reduced reproductive capacity and harvested sustainably. The spawning stock biomass (SSB) has been below the precautionary SSB level (Bpa) since 2006, but is expected to rise above Bpa (1.3 million t) in 2010.
The stock is managed according to the EU-Norway Management agreement which was revised in 2008 to account for the recent low recruitment level. ICES has evaluated this management plan and concluded that the plan is consistent with the precautionary approach.
The ICES advice for 2011 is given in three parts. The management plan gives a catch of 188 900 tonnes in the directed North Sea fisheries (Fleet A). The catch corresponds to the 15% increase in the management plan. The corresponding fishing mortalities are F(0‑1 years) = 0.050 and F(2‑6 years) = 0.121 per year. The precautionary approach and the maximum sustainable yield (MSY) approach both advices catches less than 371 200 tonnes in the directed North Sea fisheries and a by-catch ceiling of 15 200 tonnes for the EU fleet. The corresponding F(0‑1 years) and F(2‑6 years) are 0.050 and 0.25 per year, respectively.
The 2009 year class is estimated to be within the range of recent low recruitment. Therefore ICES assumes that the recruitment will remain at the lower level. The management plan has proved to be an effective tool for maintaining exploitation and conserving the North Sea herring stock. Thus the management plan should be followed and the TAC adhered to.
The realised harvest rate was long higher than the advised rate, but the fishing mortality has been considerably reduced the two last years.
Critical level of spawning stock (Blim) = 800 000 tonnes
Precautionary level of spawning stock (Bpa) = 1 300 000 tonnes
Trigger level in current management plan = 1 500 000 tonnes
Critical level of fishing mortality (Flim) = not defined
Precautionary level of fishing mortality (Fpa) = F(2-6 years) = 0.25 and F(0-1 years) = 0.12 per year
Target Fs in the current management plan: F(2-6 years) = 0.25 and F(0-1 years) = 0.05 per year
Expected fishing mortality in 2010: F(2-6 years) = 0.12 and F(0-1 years) = 0.029 per year
Expected SSB in 2010 = 1 317 000 tonnes
Agreed TAC in the North Sea 2010 = 164 300 tonnes in the directed fishery (plus an upper limit of 13 587 tonnes of by-catch in the EU fleet)
Norwegian TAC in 2010 = 47 647 tonnes
Stock size (TSB = total stock, SSB = spawning stock, million tonnes), catches (million tonnes), fishing mortality (per year) and recruitment (billions). The recruitment is given as billions of one-year-olds (0 winter ring fish).