Fay Helidoniotis
| Contact Details |
| Telephone: +61 3 6232 5004 |
| Fax: +61 3
6232 5000 |
| Location: CMAR |
| Email: fayh@utas.edu.au |
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Modelling and describing the growth of non-moulting marine invertebrates
Supervisors: Craig Johnson (UTAS) and Geoff Tuck (CSIRO)
| The Tasmanian abalone fishery is largest single managed abalone fishery in the world. The fishery supplies 30% of the wild caught abalone production (2008). Catches have been relatively consistent throughout the 45 year history and the fishery predominantly relies on one species Haltiotis rubra (blacklip abalone). The productivity of blacklip is highly variable on small spatial scales. Knowledge of growth is fundamental to fisheries management and understanding stock productivity. My project is about finding and testing the biological and management implications of variability in growth and growth model selection. |
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Introduction
A large part of the productivity of many harvested species in fisheries relates to the growth of individuals already present in each population. Numerous options exist for modelling growth in commercial species of marine invertebrates (Day and Fleming, 1992), including the von Bertalanffy (VB) curve (von Bertalanffy, 1938) and the Gompertz (GZ) curve (Gompertz, 1825). Each predicts different things, especially for juvenile growth, and decisions about how to describe growth could have important implications for the implied dynamics of the modelled stocks.
Project Outline and Objectives
- To compare and contrast the possible mathematical and statistical descriptions used to characterize the growth of commercially important marine invertebrates in Tasmania.
- To determine the potential effects upon stock assessment, for a number of important commercial species, what biases and other distortions the use of a sub-optimal growth description would have.
- To explore the generation of growth transition matrices for use in length-based models that are not dependent upon the classical growth curves commonly used but use other relationships, possibly empirical, to describe observed growth.
- To examine the effect of climate change on stock productivity, by quantifying the relationship between temperature, growth rate and size at maturity.
- To investigate the success of Legal Minimum Length in protecting spawning stock. The selection of an appropriate growth model is fundamental to the estimate of Legal Minimum Length used in safeguarding stocks.
Match to QMS Research Area
The project falls into the QMS area of Environmental Conservation and Management. It provides the quantitative decision tools and processes to enable Australia to effectively manage marine resources. The project includes: population dynamics, the science of fisheries management and possibly management strategy evaluation.
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