Final Anchovy and Sardine TACs and TABs for 2016, Using OMP-14

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1 FIHERIE//JUL/WG-PEL/26 Final nchovy and ardine TCs and TBs for Using OMP-4 Carryn L de Moor Correspondence carryn.demoor@uct.ac.za Following the recent recruit survey the revised outh frican anchovy and sardine TCs and TBs are to be recommended. The following data have been used: ) November 205 survey estimate of sardine biomass: tonnes. 2) November 205 survey estimate of anchovy biomass: tonnes. 3) May survey estimate of anchovy recruitment: billion. 4) May survey estimate of sardine recruitment: 0.8 billion. 5) Time after May that the survey commenced:.233 months (survey commenced on 8 th June) 6) nchovy recruit catch from st November to 7 th June using monthly cut-off lengths from de Moor et al. 202 and assuming recruit cut-off lengths of 9.5cm for pril 0.5cm for May and cm for June: billion 7) nchovy adult catch from st November to 7 th June using monthly cut-off lengths from de Moor et al. 202 and assuming cut-off lengths of 9.5cm for pril 0.5cm for May and cm for June:.507 billion 8) Juvenile sardine : anchovy ratio (by mass) observed in the May recruitment survey: ) Juvenile sardine : anchovy ratio (by mass) observed in the May commercial catches: ) Directed >4cm sardine TC for 205: tonnes. ) Directed anchovy TC for 205: tonnes. Using the above data the final TC and TB recommendatio are calculated by OMP-4 (de Moor and Butterworth 204) to be: Final directed >4cm sardine TC: tonnes Final 4cm sardine TB with directed >4cm sardine fishing: tonnes Final anchovy TC: tonnes Final 4cm sardine TB with directed anchovy fishing: tonnes >4cm sardine TB with directed round herring and anchovy fishing: tonnes 4cm sardine TB with directed round herring fishing: 000 tonnes nchovy TB for sardine only right holders: 500 tonnes The equatio used to calculate these TC/Bs are given in the ppendix. MRM (Marine Resource ssessment and Management Group) Department of Mathematics and pplied Mathematics University of Cape Town Rondebosch 770 outh frica.

2 FIHERIE//JUL/WG-PEL/26 Comments on the TCs s the November survey estimate of sardine abundance was less than t the buffer rule was implemented resulting in an initial directed >4cm sardine TC being recommended at the beginning of the year. The final directed >4cm sardine TC is dependent on the May survey estimate of 0.8 billion sardine recruits which was far below the historical average of 3.74 billion. This historical average is the threshold at which the final directed >4cm sardine TC would equal the original TC of t. The final directed >4cm sardine TC is thus calculated as t. The proportion of the directed >4cm sardine TC to be caught west of Cape gulhas in is unchanged from that recommended at the beginning of the year i.e. to be between and The 4cm sardine TB associated with this directed sardine TC is also revised given its dependence on the directed >4cm sardine TC. The final anchovy TC was not subject to any cotraints. Exceptional Circumstances do not apply. cknowledgements Janet Coetzee and Jan van der Westhuizen are thanked for providing the input data for these computatio. References de Moor CL Coetzee J Durholtz D Merkle D van der Westhuizen JJ and Butterworth D record of the generation of data used in the 202 sardine and anchovy assessments. Department of griculture Forestry and Fisheries: Branch Fisheries Report No FIHERIE/202/UG/WG-PEL/4. 29pp. vailable at de Moor CL and Butterworth D OMP-4. Department of griculture Forestry and Fisheries: Branch Fisheries Report No FIHERIE/204/DEC/WG-PEL/60. 27pp. vailable at 2

3 FIHERIE//JUL/WG-PEL/26 ppendix: ummary of final anchovy and sardine TC and TB equatio of OMP-4 (from de Moor and Butterworth 204). The revised sardine TC is initially calculated as: This results in TC.5 N r final TC init + R avg ( TC TC ) TC final t. The cotraint: B 205 N B ec TC final TC init does not alter the revised sardine TC. In the above equatio we have: obs N. y r - the estimate of recruitment of sardine from the hydroacoustic recruit survey in May of year y. R the level of sardine recruitment required in order to achieve the original HCR calculated avg obs B y Nov ec sardine TC. - the estimate of sardine + abundance (in thousands of tonnes) from the hydroacoustic survey in November of year y. B the biomass threshold (in thousands of tonnes) below which Exceptional Circumstances apply for sardine. The revised 4cm sardine bycatch with directed sardine fishing is calculated as follows: TB small ωtc where ϖ an estimate of the maximum percentage of 4cm sardine bycatch in the >4cm sardine catch The revised anchovy TC is initially calculated as: TC N 205 rec0 B α q p + N rec N ( p) B Nov 2 This results in TC t. s the anchovy TC in 205 was above the 2-tier threshold of t this TC is subject to the following cotraints: max 2 { TC ;( c ) c } TC c mxdn tier mxtac 3

4 which results in TC 2 FIHERIE//JUL/WG-PEL/ t. The anchovy biomass projected for November is above the Exceptional Circumstances threshold and thus no Exceptional Circumstances provisio were invoked. In addition the projected November biomass is above t and thus no smoothing is applied. In the above equatio we have: B 205 Nov - the estimate of anchovy abundance (in thousands of to) from the hydroacoustic spawner biomass survey in November 205. B Nov - the historical average index of anchovy abundance from the spawner biomass surveys from November 984 to November 999 of thousand to. N 205 rec0 ( N r e t.2 / / 2 + C0bs ) e the simulated estimate of anchovy recruitment from the recruitment survey in obs N r back-calculated to November 205 by taking natural and fishing mortality into account. N rec the average 985 to 999 observed anchovy recruitment (in billio) in May backcalculated to November of the previous year. α a control parameter which scales the anchovy TC to meet target risk levels for sardine and anchovy. p the weight given to the recruit survey component compared to the spawner biomass survey component in setting the anchovy TC. q reflects the average annual TC expected under OMP99 under average conditio if mxdn α. c the maximum proportional amount by which the normal season directed anchovy TC mxtac can be reduced from one year to the next. c the maximum directed TC that may be set for anchovy (in thousands to). tier c tier threshold for directed anchovy TC C the observed juvenile anchovy landed by number (in billio) from the st of 0bs November 204 to the day before the recruit survey commenced in. t the timing of the anchovy recruit survey in (number of months) relative to the st of May. The revised <4cm sardine TB with anchovy is calculated using: TB 2 anch λ TC + r ( TC 2 TC 2 This gives TB 3463t where λ γ r } In the above equatio we have: max{ ) 4

5 FIHERIE//JUL/WG-PEL/26 γ a coervative allowance for the ratio of juvenile sardine to juvenile anchovy in subsequent catches. r ( r + r ) sur com - the ratio of juvenile sardine to anchovy in the sea during May calculated from the recruit survey and the sardine bycatch to anchovy ratio in the commercial catches during May. Only commercial catches comprising at least 50% anchovy with sardine bycatch are coidered. 5