A “cautioned assessment” is based on recruitment data, Catch per Unit Effort (CPUE) indices and data on spawning escapement; no formal stock assessment is conducted. Biomass estimates are not available for any of the stocks; reliable relative abundance is only based on CPUE data (MPI, 2012). A population dynamics stock assessment model is being developed (MoF, 2009).
The Eel Fishery Assessment Group (EFAG), under the Ministry for Primary Industries (MPI), evaluate the state of the fisheries and stocks and analyze management scenarios, not being responsible by management recommendations or decisions which are taken by the MPI. A final decision is discussed in a multi-stakeholder meeting (MPI, 2012). The TACC is based on former catches trends in lack of biological data and analysis. Considering the distribution and exploitation of shortfin eel, Jellyman (2007) recommends the shared management of the stock by New Zealand and Australia cooperatively; efforts are in place (DEPI, 2010).
The catch composition that mainly comprises immature females, justifies the closely monitoring and management of the stock. The effect of the migration of juveniles and contribution to spawning escapement of the stock of shortfin eels is not known (Jellyman, 2007). Research activities were considered by the MPI to improve the knowledge, status and consequently the management of the stock (MoF, 2009).
Reference points are not defined.
Current biomass estimates are not available. Reported landings are at 27,070 tons for the 2012/2013 fishing season. Captures is mainly composed of immature females of shortfin eels since males migrate with <220g (MPI, 2012).
The relative abundance estimate for the South Island, based on CPUE indices, demonstrates an increase from 2001/2002 to 2005/2006. Reported catches oscillated between 63,600 tons in 2001/2002 and 95,400 tons in 2002/2003 to around 120,000 tons during 2003/2004-2007/2008. A decrease occurred in 2010/2011 at 89,300 tons but catches increased again 2011/2012 to 117,960 tons (MPI, 2012).