Comparisons of alternative single-area sardine TAC Management procedures

The Small Pelagic Scientific Working Group has requested further testing of Candidate Management Procedures allocating a single-area sardine Total Allowable Catch (TAC) for possible update of Interim OMP-13 v2 for use in setting the 2014 initial sardine and anchovy TACs and Total Allowable Bycatches (TABs). This is planned as a temporary measure, while further testing continues in comparing Candidate MPs which allocate a single-area sardine TAC to those which allocate a two-area sardine TAC

A list of the TACs and TABs required as output from OMP-12

A revision of the TACs and TABs output from the joint sardine and anchovy OMP is required. This is firstly to account for a change in the specification of bycatch in the landings from 2011 (de Goede 2011) and secondly to make allowance for some landings which have historically been ignored as they have not been landed under a permit. This document lists the TACs and TABs that were recommended by OMP-08 and those to be recommended by OMP-12 and makes some suggestions for how the new TAC/Bs to be recommended by OMP-12 will be calculated

Were the survey observations of anchovy during 2011 outside the range simulated during OMP-08 development

At the Small Pelagic Scientific Working Group Meeting on 29th February 2012, some queried whether the below average survey observations of anchovy during 2011 warranted a change to the TAC constraints used in OMP-08. This was considered under the general protocol for OMPs for South African fisheries which cater for unanticipated events and can lead to the initiation of a review of an OMP ahead of the schedule (see Appendix 2 of Rademeyer et al. 2008). In this document, a simple check is performed to evaluate whether the 2011 survey estimates of anchovy abundance were outside the major part of the range (typically to 90% or 95% PI would be the norm) simulated during the testing of OMP-08

Model projections from November 2003

The simulation testing framework used during the development of recent Interim OMPs is based on assessments that have been conditioned on data up to and including November 2011 (de Moor and Butterworth 2013). Projections thus begin from November 2011. In this document, the initial starting conditions for projections are changed to match those of November 2003, and the model is run for eight years to compare with observations between November 2004 and 2011

The projected range of total sardine biomass

Figure 1 shows the histogram of the projected range of future hydroacoustic survey estimates of sardine 1+ biomass that were simulated during the testing of OMP-08 (de Moor and Butterworth 2008) and Interim OMP-13 v2 (de Moor and Butterworth 2013). Assuming a single sardine stock hypothesis, the cumulative simulated probability of obtaining a survey estimate of sardine 1+ biomass of less than 750 thousand tons was simulated to be 21% under OMP-08 and 29% under Interim OMP-13 v2. Assuming a two sardine stock hypothesis, the cumulative probability of obtaining a survey estimate of sardine 1+ biomass of less than 750 thousand tons was simulated to be 86-87% under “MoveE1 ” and “MoveB2 ” and 24% under “NoMove3 ”

An alternative two mixing stock hypothesis for South African sardine

The results of the two mixing stock hypothesis for South African sardine presented in de Moor and Butterworth (2016) assumed recruitment to each coastal management unit was dependent only on the spawner biomass (SSB) of that coastal management unit. In this document some contribution from the south coast SSB to the effective west coast SSB is considered as an alternative two mixing stock hypothesis

OMP-14: Alternative initial directed sardine TAC Rules

The latest Candidate Management Procedure (CMP) proposed to be used as the next Operational Management Procedure (OMP) for the South African sardine and anchovy fishery, OMP-14, is detailed in the Appendix. The Small Pelagic Scientific Working Group has previously agreed the form of the rule governing the increase in the directed sardine TAC in cases where the November survey estimate of 1+ biomass is between 300 and 600 000t, and only a portion of the original TAC is recommended at the start of the year. The OMP Task Team agreed in September 2014 that the increase would continue to be dependent on the historical observed 1985-2011 average of 13.74 billion, with a critical value of Rcrit = 2.1 × Avg rec = 48.16 billion. This document shows the results of assuming different alternatives to the rule governing the portion of the directed sardine TAC recommended at the start of the year in cases where the November survey estimate of 1+ biomass is between 300 and 600 000t. In addition, the maximum possible increase is now smoothed from 110% of the original TAC at 300 000t, to 100% of the original TAC at 600 000t. All results in this document are based on a single sardine stock operating model

Further work on a risk analysis of the impact of harvesting sardine on the west coast of South Africa

de Moor and Butterworth (2016a) undertook an initial risk analysis to consider the risk to the sardine resource for the 2016 season, in terms of the west coast harvest proportion. This analysis was to assist in discussions regarding the implementation of the "Gentleman’s agreement" that the South African pelagic industry self-regulate fishing pressure west of Cape Agulhas to ensure the spread of fishing west compared to east of Cape Agulhas is similar to that observed during recent November surveys (further details provided in de Moor and Butterworth (2016a))