Fisheries

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Fisheries Modelling

The Fisheries Modelling subprogram conceives, develops and maintains stock assessment models of South Australian fisheries, and provides quantitative scientific and statistical advice to PIRSA Fisheries. Click here to download the Fisheries Modelling subprogram capability statement (.pdf).Dr Rick McGarvey, Fisheries Modelling subprogram leader, (closely) examines graphs illustrating the slice partition method they developed to enumerate fish populations, in stock assessment models, by both the lengths of the fish, as well as by their ages.

Overview

The Fisheries Modelling subprogram provides modelling, data analysis and statistical support for the Wild Fisheries Program.  Three main areas of application are;

  1. using catch and effort data, and samples by age and length, to estimate management indicators, such as yearly biomass, recruitment, and harvest fraction, which characterise the health of South Australian fish stocks,
  2. fishery survey design, data analysis and GIS mapping, and
  3. developing new statistical methods to estimate fishery and food web change over time (dynamics) using commonly available data sets.

Models developed by this subprogram include;

  1. stock assessment models for rock lobster, King George whiting, garfish, and snapper,
  2. Windows management simulation software with GUI’s and user manuals for rock lobster, giant crab, and King George whiting,
  3. movement rate estimation models,
  4. growth models for rock lobster, giant crab, King George whiting, snapper, and garfish,
  5. fishery-dependent survey designs for rock lobster and blue crab, and
  6. fishery-independent diver survey design and analysis for rock lobster and abalone.

Statistical outcomes of the subprogram include;

  1. accurate estimates of lobster biomass and yearly recruitment using only catch and effort data (qR model),
  2. estimates of fish movement rates which require fewer assumed inputs such as the rate of fisher non-reporting of recaptured tags,
  3. a statistical method for estimating the time between moulting for crustaceans,
  4. a new method to model both the age and length of fish stocks (slice-partition),
  5. for egg survey, a method to estimate spawning biomass without staging the sampled eggs,
  6. flexibly estimated growth transition rates that quantify the change in female lobster growth at maturity,
  7. a new abalone diver survey design, by leaded-line transects, which yields estimates of the legal abalone biomass available for harvesting rather than a relative measure of abundance,
  8. GIS mapping of surveyed population density and mean size,
  9. time-at-large estimates of mortality from tag recoveries.

Future goals include expanding the current suite of fishery models to incorporate food web, by-catch and other ecosystem processes.

Recent Publications

McGarvey, R., Mayfield, S., K. Byth, T. Saunders, R. Chick, B. Foureur, J.E. Feenstra, P. Preece, and A. Jones. 2008. A diver survey design to estimate absolute density, biomass and spatial distribution of abalone. Canadian Journal of Fisheries and Aquatic Sciences: 65(9): 1931-1944.

McGarvey, R., Feenstra, J.E., Ye, Q. 2007. Modeling fish numbers dynamically by age and length: partitioning cohorts into ‘slices’. Canadian Journal of Fisheries and Aquatic Sciences 64: 1157-1173.

McGarvey, R., A.E. Punt and J.M. Matthews. 2005. Assessing the information content of catch-in-numbers:  a simulation comparison of stock assessment methods based on catch and effort totals. pp. 635-653, In: G.H. Kruse [ed.], Fisheries Assessment and Management in Data-Limited Situations.

McGarvey, R., K. Byth, C.D. Dixon, R.W. Day, and J.E. Feenstra. 2005. Field trials and simulations of point-nearest-neighbour distance methods for estimating abalone density. Journal of Shellfish Research 24: 393-399.

McGarvey, R. 2004. Estimating the emigration rate from marine reserves using tag-recovery data. Fishery Bulletin 102: 464-472.

McGarvey, R. 2003. Demand-side fishery management:  integrating two forms of input control. Marine Policy 27: 207-218.

McGarvey, R., and J.E. Feenstra. 2002. Estimating rates of fish movement from tag-recoveries: conditioning by recapture. Canadian Journal of Fisheries and Aquatic Sciences 59: 1054-1064.

Contacts

Dr. Richard McGarvey
Subprogram Leader
Tel: 08 8207 5400   Fax: 08 8207 5481
PO Box 120, Henley Beach, SA, 5022
E-mail: richard.mcgarvey@sa.gov.au