2nd National Abalone Convention 2003
A scoping study on the Australian abalone industry
Identification workshop of marine invasive worm species. Such worms impact on the oyster industry, and other aquaculture activities as well changing benthic habitats which can impact on wild stocks
Every year large numbers of exotic marine species are accidently introduced into Australian waters as a result of vessel fouling, ballast water release, aquarium trade, or through aquaculture associated stock movement. Although the majority of exotics do not establish viable populations, over 250 aquatic invasives have become notorious pests (www.marinepests.gov.au) that have significant direct economic impact on aquaculture and fisheries industries. Indirect impact include blocking industrial water intake and outlet pipes, fouling of commercial and recreational vessels as well as modifying natural ecosystems by competing for food and space with indigenous species. The costs to industry, government, and the environment are significant and ongoing. The best prevention of pest spread is their early recognition and eradication by field workers, as once established eradication is almost impossible. This, however, entails the correct initial identification of the species. Because many exotic species closely resemble native species, it is critical to distinguish between native and introduced species that already occur here as well as to recognise new introductions. Training of stakeholders to recognise introductions and develop working relationships with the relevant taxonomic experts is critical so that this can be ongoing, which will facilitate early detection and development of emergency management strategies. The workshop attendees will be shown how to collect and preserve worms in order to be able to identify them and which characters are critical to examine. This will involve hands on experience in identification of potential pests and plenty of opportunities for face to face contact and informal communication with established experts in the field to develop relevant skills. Each participant will receive a fully-illustrated guide to facilitate identifications in the work place. The guide will contain previously unpublished data and will continually be updated as new information becomes available, also for sale to non-workshop participants.
Final report
Testing established methods of early prediction of genetic merit in abalone broodstock
There is a need in the abalone industry to improve production animals. However, abalone are relatively slow growing animals and take several years to reach harvest size. This means that during the establishment of foundation broodstock populations it may be several years before the relative genetic merit of each of the broodstock can be determined and the first selection decisions made. During this time, the hatchery manager will have to blindly spawn broodstock to stock the farm, often with broodstock possessing poor gEBV and that produce slow growing animals. This comes at the additional cost of not being able to cull poor performing broodstock early in the establishment of the population and replacing them with new broodstock.
Through measuring the family performance (and thus broodstock gEBV) of these cellular traits in larvae and comparing broodstock gEBV with those derived from progeny at harvest, a high genetic correlation would indicate that it is possible to predict genetic merit using these cellular traits. Studies have shown that the ratio between RNA and DNA in cells has a high heritability (necessary for the traits to have predictive power) and that it can be used to accurately predict the gEBV of barramundi broodstock without the necessity of rearing progeny all the way through to harvest (genetic correlation >0.8). Therefore, using RNA/DNA as the trait to measure in barramundi larvae it is now possible to establish high performing broodstock foundation populations via mass-spawning broodstock, estimating their genetic merit based on larvae RNA/DNA, and then eliminating those broodstock with inferior gEBV from the breeding population.
Several Australian barramundi hatcheries now apply this technique to assist in the selection of broodstock. This method is as yet untested in abalone, but if successful, has great potential in helping screen broodstock. This project will test the efficacy of this early prediction method in abalone. The impact of this early detection method would be to save costs by assisting in the selection of superior broodstock individuals which would produce faster growing offspring. Currently new broodstock animals are unevaluated with regard to their genetic merit.
Final report
The implications of this study are that grow out of progeny to harvest size (or close to) is currently still required to determine the genetic merit of abalone broodstock in selective breeding programs. Furthermore, future studies following the same individuals in a cohort through time are required to better understand the result that the genetic effect is only realised at the harvest stage. This work is required to better inform current grading practices. Furthermore, a moderate heritability for growth traits was detected and so there is also potential for farmers to improve growth of stock through selection.
Testing abalone empirical harvest strategies, for setting TACs and associated LMLs, that include the use of novel spatially explicit performance measures
Recent declines in Eastern Tasmania (Tarbath & Gardner, 2012) and Tiparra Reef in South Australia (Chick & Mayfield, 2012) suggest a potential for changes in productivity. Further challenges to successfully managing abalone include periods of poor recruitment in some areas, rising Australian east coast temperatures, the Victorian virus outbreak, toxic blooms in Tasmania, and mortality events in Tasmania.
All these challenges to current management indicate the need for more detailed and rapidly reactive and defensible management of Australian abalone stocks.
The management strategy evaluation (MSE) framework from FRDC 2007/020 “Biological Performance Indicators for abalone fisheries”, focussed on the utility of classical performance measures. However, the Multi-Criterion-Decision-Analysis Harvest Strategy (MCDA-HS) being developed in Tasmania will integrate classic fishery Performance Measures (PMs) with new Spatial PMs, and include local complexity in growth (the latter are important for the TAC/LML debate). Now GPS data loggers have become compulsory within the Tasmanian fishery (2006/029 – “Using GPS technology to improve fishery-dependent data collection in abalone fisheries”), the need to test these new empirical harvest strategies, that include spatial PMs, is becoming urgent. The MSE framework, therefore needs modification to successfully simulate the new spatial performance measures and then test the performance of the novel harvest strategies. South Australia introduced a non-spatial MCDA-HS without testing and an array of unintended consequences is becoming apparent. To retain confidence in the application of formal harvest strategies with associated decision rules testing the harvest strategies as they are developed remains important.
Novel harvest Strategies need to be tested to determine by how much they improve the setting of TACs and associated LMLs. There is a recognized need to interact with FRDC 2011/201: “Implementing a spatial assessment and decision process to improve fishery management outcomes using geo-referenced diver data” so both projects can benefit from each other.
Final report
The management of abalone stocks is difficult for many reasons including their high value and the exceptional levels of spatial structuring found in their stocks. In Tasmania, for example, suggestions to change such things as a legal minimum length or introduce a formal harvest strategy to replace the current relatively informal process, always engender high levels of sometimes heated debate. An aim of this work, conducted by Malcolm Haddon and Craig Mundy of CSIRO and the University of Tasmania respectively, was to formally examine the implications of changing legal minimum lengths and the importance of such LML to the management of abalone. This was in the context of using management strategy evaluation to test alternative potential harvest strategies for use, in the first place, within the Tasmanian abalone fisheries. With the advent and growth of more public scrutiny of wild fisheries a need for a more defensible, repeatable, and publically available process for setting abalone TACs had become urgent. This project aimed to contribute to the development of such formal harvest strategies that would both successfully generate workable management advice and be defensible under anyone’s scrutiny.