18 results
Environment
PROJECT NUMBER • 2003-019
PROJECT STATUS:
COMPLETED

National Strategy for the Survival of Released Line Caught Fish: investigating survival of fish released in Australia’s tropical and subtropical line fisheries

Experiments were conducted in northern, central and southern Queensland to investigate the effects of hook design and size on the incidence of hooking injury, and the effects of a number of factors, including barotrauma-treatment method, on post-release survival rates of a suite of key...
ORGANISATION:
James Cook University (JCU)
TAGS
Wild Catch
Tagging
Survey
Recreational Fishing
Fishing Gear
SPECIES
Redthroat Emperor
Spangled Emperor
Saddletail Snapper
Crimson Snapper
Red Emperor
Environment
Industry
Industry
Environment
PROJECT NUMBER • 2018-034
PROJECT STATUS:
COMPLETED

Effects of climate change and habitat degradation on Coral Trout

Fishes are at considerable risk from changing environmental conditions because they are, for most part, unable to regulate their body temperature. Exposure to high temperatures may therefore compromise critical biological functions, resulting in reduced performance, fitness and ultimately survival....
ORGANISATION:
James Cook University (JCU)
TAGS
Stock Assessment
Recreational Fishing
Rac Qld
Population Dynamics
Oceanography
SPECIES
Coral Trouts
Adoption
PROJECT NUMBER • 2018-049
PROJECT STATUS:
COMPLETED

A Better Way to Fish: testing the feasibility of tunnel net ‘fish trap’ gear in North Queensland

This study found that tunnel nets are technically feasible in this location. In spite of the weather conditions, the fishing gear remained intact and successfully captured significant numbers of marketable fishes. Importantly, SOCI species were released alive and in excellent condition, as were...
ORGANISATION:
James Cook University (JCU)
TAGS
Threatened Endangered Protected Species
Sustainability
Stakeholder
Rac Qld
Policy
SPECIES
King Threadfin
Blue Threadfin
Diamondscale Mullet
Sea Mullet
Striped Perches
Industry

Testing established methods of early prediction of genetic merit in abalone broodstock

Project number: 2017-220
Project Status:
Completed
Budget expenditure: $85,422.00
Principal Investigator: Jan Strugnell
Organisation: James Cook University (JCU)
Project start/end date: 3 Jun 2018 - 30 Dec 2020
Contact:
FRDC
SPECIES
Blacklip Abalone
Greenlip Abalone

Need

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.

Objectives

1. Assess the utility of RNA/DNA ratio as a method for early prediction of high performing abalone broodstock

Final report

ISBN: 978-0-6454198-2-5
Authors: Phoebe Arbon Dean Jerry Jan M. Strugnell
Final Report • 2022-05-01 • 2.99 MB
2017-220 DLD.pdf

Summary

This report provides an assessment of the utility of RNA/DNA ratio as a method for early prediction of high performing abalone broodstock. The study was carried out on farmed Greenlip Abalone (Haliotis laevigata) whereby families were produced and resulting progeny were reared using commercial protocols. RNA/DNA ratio and shell length were measured in post larvae, and shell length, shell width and total weight were measured in juveniles and harvest sized individuals. All individuals were genotyped, parentage was assigned and heritability and genetic correlation of traits was calculated. Analyses in post-larvae and juveniles could not estimate heritability of traits including RNA:DNA and shell length indicating that the additive genetic variance component of these traits were unable to be separated from non-genetic components (e.g., environment) at early production stages (i.e. post-larvae and juveniles). This indicates that further grow out would be required to assess broodstock quality for use in breeding programs. The project was carried out between 2019-2022 by Phoebe Arbon, under the supervision of Prof. Jan Strugnell and Prof. Dean Jerry, based within the Department of Aquaculture at James Cook University, Australia.
There was no detectible heritability of post-larval traits including RNA:DNA and shell length. Therefore, the genetic potential of broodstock was not able to be predicted using progeny performance at the earlier life stages (i.e., post larvae or juveniles). This is likely to be due to a strong influence of environmental factors at early life stages. At harvest size, however, all production traits (shell length, width and animal weight) had a significant additive genetic component. Therefore, realisation of a genetic effect only occurred in the later harvest stage of production and was masked at the earlier stages of production (i.e., post-larvae and juvenile stages).
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.
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