Weighting of catch at age data in stock assessment models

Trophia is contracted by the New Zealand Ministry of Fisheries (MFish) to develop techniques to improve the stock assessment of harvested fish stocks. Specific objectives include: To determine the appropriate weighting of catch at age data in stock assessment models Stock assessment models often use data inputs from a variety of sources, including catch sampling and abundance surveys. The biomass indices obtained from abundance surveys (or CPUE analysis) are assumed to follow… Read More

Characterisation of the New Zealand tuna fisheries

Trophia has been contracted by the New Zealand Ministry of Fisheries (MFish) to To characterise the New Zealand tuna fisheries, including catches of important associated tuna like species. The specific objectives for this project include: 1. To characterise the New Zealand tuna fisheries for albacore (Thunnus alalunga), bigeye tuna (T. obesus), Pacific bluefin tuna (T. orientalis), skipjack tuna (Katsuwonus pelamis), southern bluefin tuna (Thunnus maccoyii), yellowfin tuna (T. albacares), and swordfish (Xiphias… Read More

Investigation of potential improvements to the TRE 7 stock assessment

The Ministry of Fisheries research project “TRE 2001/02 Stock assessment of trevally in TRE 7″ was completed by Trophia and included an analysis of CPUE and stock assessment modelling. The results were presented to the Pelagic Fisheries Assessment Working Group in February 2003. In reviewing the results of the project, the WG identified two areas where additional work was needed: The high inter-annual variability in CPUE The potential for age-specific mortality The… Read More

Characterisation of white and blue warehou fisheries

Trophia has been contracted by the New Zealand Ministry of Fisheries (MFish) to review the status of the major blue warehou (Seriolella brama) and white warehou (Seriolella caerulea) fishstocks. The specific objectives for this project include: 1. To characterise the blue warehou fisheries by analysis of existing commercial catch and effort data up to 2002/03, and review the data from research trawl surveys and Observer logbooks to determine any trends in size… Read More

Adaptive Management Programme proposals and monitoring

Trophia is contracted for a second year by the New Zealand Seafood Industry Council (SeaFIC) to assist with analyses required under the the adaptive Management Programme. The adaptive Management Programme (AMP) was introduced in 1991 by the NZ Ministry of Fisheries (MFish) as a basis for varying the levels of Total Allowable Commercial Catch (TACC) of fishstocks for which there is limited information on stock size. New proposals include a descriptive analysis… Read More