MARAM_TRISTAN_2014_MAR_06.pdf (7.8 MB)
Download file

Updated 2014 Nightingale island rock lobster assessment

Download (7.8 MB)
posted on 09.05.2022, 11:42 authored by Susan HollowaySusan Holloway, Doug ButterworthDoug Butterworth

This paper provides an updated assessment of the rock lobster resource at Nightingale island. This assessment includes updated data from both the commercial fishery and biomass surveys. The 2014 assessment updates take into account both adult and juvenile mortality due to the OLIVA incident in 2011. The recent (2013) high nominal CPUE value at the island is unexpected, and suggests that the impact of the OLIVA may have been overestimated. A number of robustness trials are therefore run where alternate levels of both juvenile and adult mortality in 2011 due to the OLIVA incident are assumed. The implications of these assumptions for the future management of this resource are discussed. The recent high CPUE probably indicates that the adult mortality in 2011 due to the OLIVA incident was minimal. However, the effect of any juvenile mortality due to the OLIVA will only become evident from CPUE trends over the next few years; such mortality could result in a large drop in abundance over this period. In these circumstances it is recommended that the TAC for Nightingale for the 2014/15 season remain unchanged at 65 MT, and that modifications to this in subsequent seasons be based on future CPUE trends.



Department of Mathematics and Applied Mathematics, University of Cape Town