Monitoring rig fisheries in SPO 1 and SPO 8

Trophia was contracted by the New Zealand Ministry of Fisheries to continue monitoring changes in the rig fisheries and the relative abundance of rig (Mustelus lenticulatus) stocks in SPO1 and SPO8. Specific objectives for the project were:

  1. To characterise the SPO 1 and SPO 8 fisheries.

  2. To update the SPO 1 and SPO 8 standardised CPUE series to the 2009/10 fishing year.

Following the introduction of rig to the QMS in 1986, landings of both SPO 1 and SPO 8 were constrained by the new TACCs until they were increased by 20% for the 1991–92 fishing year under the Adaptive Management Programme (AMP). Catches of rig have declined steadily in SPO 1 since 1991-92 and since 1995–96 in SPO 8, and they were removed from the AMP in July 1997. The TACCs for SPO1 and SPO 8 reverted to the pre-AMP levels in the 1997–98 fishing year, but catches have remained well below TACCs since then.

Rig has previously (Blackwell et al. 2006, Manning in prep) been monitored in discreet set net fisheries in sub-stock areas for Thames, SPO 1E other, Kaipara, Manukau, SPO 1 W other, and SPO 8. The analyses were done on positive catches from targeted fishing and were last updated to the 2006-07 fishing year. CPUE indices in each sub-area have trended flat in most areas except for Manukau Harbour which declined steadily until the early 2000’s and then showed some recovery, and Thames (SPO 1E) which was increasing steeply at last assessment.