New Zealand Journal of Marine and Freshwater Research abstracts
Can additional abundance indices improve harvest control rules for New
Zealand rock lobster (Jasus edwardsii) fisheries?
Nokome Bentley
Trophia
P.O. Box 60
Kaikoura, New Zealand
email: nbentley@trophia.com
Paul A. Breen
Susan W. Kim
National Institute of Water and Atmospheric
Research Limited
P.O. Box 14 901
Wellington, New Zealand
email: p.breen@niwa.co.nz
email: s.kim@niwa.co.nz
Paul J. Starr
61A Rhine St
Island Bay
Wellington, New Zealand
email: paul@starrfish.net
Abstract Although New Zealand rock lobster (Jasus
edwardsii) fisheries can be assessed with a sophisticated Bayesian length-based
model, these assessments are expensive and time consuming; they cannot be
conducted for each area every year. Harvest control rules are increasingly
important management tools in New Zealand rock lobster fisheries. Recent
work has developed and evaluated procedures for rebuilding or maintaining
lobster stocks based on criteria agreed by stakeholders. Most management
procedures depend on a single abundance index, often catch per unit of effort
(CPUE). When management procedures react slowly to changes in vulnerable
biomass, allowable catches get out of phase with the stock, causing large
oscillations in both catches and CPUE. Lags between data and management actions
and “latent years” are features of rules that reduce responsiveness. This
study explores ways to improve the responsiveness of harvest control rules
by using additional data to predict changes in vulnerable biomass. Four data
sets are examined: CPUE trends, pre-recruit indices, puerulus settlement
indices, and size frequencies. Only pre-recruit indices, which were explored
with a simple delay-difference model based on parameter estimates from recent
assessments, appeared to have immediate potential for use in improving management
procedures.
Keywords decision rules; management procedures; abundance
indices; pre-recruit indices
M04028; Online publication date 8 June 2005 Received 9 February 2004;
accepted 17 August 2004
New Zealand Journal of Marine and Freshwater Research, 2005, Vol. 39:
629-644
0028-8330/05/3903-0629 © The Royal Society of New Zealand 2005
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