213 results
Environment
PROJECT NUMBER • 2018-120
PROJECT STATUS:
COMPLETED

NCCP: Population dynamics and Carp biomass estimates

This study was undertaken by the Arthur Rylah Institute for the Department of Environment, Land, Water and Planning. Carp (Cyprinus carpio) is Australia’s most invasive pest fish. To facilitate more effective management, the Australian Government is considering release of a Carp herpesvirus...
ORGANISATION:
Department of Environment Land Water and Planning (DELWP)
Environment
PROJECT NUMBER • 2014-019
PROJECT STATUS:
COMPLETED

Developing a fishery independent estimate of biomass for snapper

This study was undertaken by the South Australia Research and Development Institute (SARDI). Through overcoming considerable technical challenges, this study was the first to successfully develop a relatively non-destructive molecular probe that can reliably identify Snapper (Chrysophrys auratus)...
ORGANISATION:
SARDI Food Safety and Innovation
SPECIES

Cephalopod beak identification and biomass estimation techniques: tools for dietary studies of southern Australian finfishes

Project number: 1995-048
Project Status:
Completed
Budget expenditure: $56,636.00
Principal Investigator: Chung Cheng Lu
Organisation: Melbourne Museum
Project start/end date: 29 Jun 1995 - 10 Jun 2004
Contact:
FRDC

Objectives

1. To produce a diagnostic illustrated key for identification of cephalopod beaks in the diets of marine vertebrates from southern Australian waters.
2. To analyse relationships between beak morphometrics and whole animal attributes, in order to develop back-calculation formulae for estimation of prey size and biomass.

Final report

ISBN: 0-7311-7253-1
Author: Chung Cheng Lu
Final Report • 2003-12-08 • 7.76 MB
1995-048-DLD.pdf

Summary

Squid, octopus and cuttlefish (cephalopods) are known to be an important food source for many marine animals including whales, porpoise, seals, seabirds, tuna, sharks and swordfish. The hard beaks (chitinous mandibles) of these preys are frequently encountered in predator stomachs. Cephalopod beaks can be used to identify the prey species and to calculate prey size and biomass consumed. Such hard parts from fishes (i.e. otoliths and vertebrae) have long been used for these purposes. Cephalopod species in the northern hemisphere have also had such tools available, but until now little information has been available on this aspect of the cephalopod fauna of our region.
 
A key of cephalopod beaks of 75 southern Australian species is available to identify samples taken from predators in this region for the first time, along with the formulae required to calculate prey size and biomass. 
Production of this key required the analysis of 1596 specimens, involving detailed measurements of various parts of the whole animal (mantle length, animal weight) and the beaks. Statistical analysis of the data then allowed the description of the relationship between beak measurements and the size and weight of animals, providing formulae to back calculate prey size and biomass.

A table provides details of the species examined, classified to order and family, with information on the size and weight range of whole animals. Most complete beaks can be easily identified to the order level and a key is provided for this. Further keys are provided to allow identification to genus/species level within each of the four orders. Detailed descriptions of beaks are provided for each species, supplemented by further tables providing ranges, ratios and means of various beak characters.

A desk-top evaluation of the application of towed-body LIDAR to biomass assessment of demersal fish stocks

Project number: 1993-240
Project Status:
Completed
Budget expenditure: $5,700.00
Principal Investigator: Ronald E. Thresher
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 29 Jun 1994 - 30 Jun 1996
Contact:
FRDC

Objectives

1. To undertake a desk-top study to assess the potential of towed-body LIDAR for biomass determination of demersal fish stocks

Assessment of broad-scale exploitation rates and biomass estimates for the Tasmanian southern rock lobster fishery

Project number: 1997-101
Project Status:
Completed
Budget expenditure: $468,370.00
Principal Investigator: Stewart Frusher
Organisation: University of Tasmania (UTAS)
Project start/end date: 22 Jun 1997 - 29 Apr 2003
Contact:
FRDC

Need

Traditionally, catch per unit of effort (CPUE) is used to monitor the health of the fishery and indicate the success or otherwise of management practices. Under current input controls CPUE is based on fishers maximising their total catch. In contrast, under output controls where catch is predetermined fishers will alter their catching scenarios to maximise the return (dollars per kilogram) from their catch. In southern rock lobster fisheries there is significant potential to alter fishing patterns to maximise economic return, especially through seasonal shifts in effort. As this change occurs, the value of using CPUE data to continue monitoring the fishery will be eroded. As such, both fisheries independant means of monitoring the fishery and new monitoring methods will become increasing important.
Both exploitation rates and biomass estimates are important stock assessment parameters and biological reference points in sustainable management of fisheries resources.
This project will evaluate fishery independant means of deriving these estimates and by determining the precision of derived estimates, demonstrate their suitability as biological reference points.
In a report to the Department of Industry, Technology and Commerce titled "Oceans of Wealth?", the Review Committee on Marine Industries, Science and Technology stated in their conclusion, 'The knowledge gained from scientific research into fish stocks and the impacts of the environmental and harvesting factors is a necessary but not sufficient element in the conservation of productive fish stocks. A vital element in both scientific assessments is the availability of reliable information about exploitation levels'. This project is aimed at addressing this need for southern rock lobster.

Objectives

1. To assess the precision of exploitation rates and biomass estimates derived from broad scale sampling using fisheries independant and fishery dependant sampling.
2. To evaluate both the precision and cost effectiveness of biomass estimation from fisheries dependant and fisheries independent derived exploitation rates and recommend future monitoring methodology for the rock lobster fishery.

Final report

ISBN: 1-86295-079-2
Author: Stewart Frusher
Final Report • 2003-03-25 • 2.06 MB
1997-101-DLD.pdf

Summary

Exploitation rate is an important fishery assessment parameter linking catch to legal-sized biomass, the portion of the stock available for harvest.  Relative change in legal-sized biomass is a crucial performance indicator for the fishery as it measures the success of management outcomes.  Under the recently introduced Individual Transferable Quota Management System (ITQMS) in the Tasmanian rock lobster fishery, rebuilding of legal-sized biomass is a key management objective.  The assessment model that produces biomass estimates for this fishery is primarily dependent on commercial catch and effort data. 

The use of commercial catch and effort data for stock assessment relies on its de facto relationship with stock abundance.  However, the relationship between catch and effort data and abundance is not always constant or linear.  Improvements in fishing gear and technology can result in greater catch for a given amount of effort, unrelated to changes in the biomass.  Management changes and fishers’ behaviour can also affect the relationship between catch rates and biomass.  Under the new ITQMS introduced in 1998, catch is fixed and improved profits can be made by improving the return per unit of fish caught rather than by increasing the amount of catch through increased effort.  Thus fishing during periods when catch rates are low but price is high can change the catch effort relationship independent of biomass change.

Fishery independent surveys, using established sampling protocols and standardised fishing gear are a way in which catch rates can be standardised irrespective of gear efficiencies or fisher’s behaviour.  If these surveys can also produce accurate estimates of exploitation rate then accurate estimates of biomass can be achieved, provided the exploitation rate estimates are representative of the fishing grounds.  Fishery independent estimates of exploitation rate are thus a valuable way of validating model biomass estimates especially with the introduction of an ITQMS where the relationship between catch rates and legal-sized biomass was likely to change pre- and post-quota.

This project aimed to trial change-in-ratio (CIR) and index-removal (IR) techniques to obtain estimates of exploitation rate and biomass from broad scale regions in the fishery.

Keywords: southern rock lobster, change-in-ratio, index-removal, exploitation rates, tagging.

Environment
PROJECT NUMBER • 2020-065
PROJECT STATUS:
CURRENT

Indicators for density and biomass of exploitable abalone – developing and applying a new approach

The objectives of this project are to use the Victorian Western Zone (WZ) abalone fishery to develop and evaluate a new approach to calculating abalone density and biomass indicators from the combination of three information sources. The three information sources are: i. ...
ORGANISATION:
Western Abalone Divers Association (WADA)

Evaluation of egg production as a method of estimating spawning biomass of redbait off the east coast of Tasmania

Project number: 2004-039
Project Status:
Completed
Budget expenditure: $398,417.47
Principal Investigator: Jeremy Lyle
Organisation: University of Tasmania (UTAS)
Project start/end date: 30 Aug 2004 - 24 Apr 2008
Contact:
FRDC
SPECIES

Need

Redbait are an important component of the pelagic ecosystem, being a major consumer of zooplankton and a prey species for predators such as tunas, birds and mammals. The introduction of large-scale mid-water trawl operations (2001) to target small pelagics in Zone A of the Small Pelagic Fishery has produced catches of redbait that have no precedent locally and there is real potential for further rapid expansion. Little information is available on the biology or population dynamics of redbait, and there are no assessments of stock size on which to base TACs, currently set at 34,000t (combined species, including management triggers).

The development of a method for estimating redbait biomass is urgently required to support the setting of scientifically defensible TACs. Fishery-dependent methods of assessing fish stocks are generally unsuitable for small pelagic species due to their schooling behaviour and targeted nature of the fishing operations. Furthermore, due to the very recent development of mid-water trawling targeting redbait, no time series of data are available to detect changes in redbait stocks off Tasmania. The daily egg production method (DEPM) has been applied successfully for biomass estimation of a variety of small pelagic species, and is deemed suitable for estimating redbait biomass. There are advantages in generating biomass estimates as early as possible in the development of this fishery, if fishery impacts are to be detected and managed.

FRDC has supported the evaluation of DEPM for blue mackerel (Project 2002/061), a species that co-occurs with redbait. There are considerable efficiencies in establishing linkages with this project in terms of research focus, expertise and resources. However, as redbait have a different spawning season to blue mackerel, the timing of blue mackerel egg surveys are not appropriate and therefore additional research is required to evaluate the feasibility of using DEPM for redbait.

Objectives

1. To estimate the critical reproductive parameters for redbait along the east coast of Tasmania, particularly spawning fraction and batch fecundity.
2. To develop and validate methods for identifying and staging the eggs and larvae of redbait.
3. To estimate the location and extent of spawning areas of redbait on the east coast of Tasmania, including a quantification of the levels of egg production of this species.
4. To evaluate the use of the daily egg production method for estimating the spawning biomass of redbait on the east coast of Tasmania.
5. To produce a minimum biomass estimate of redbait in the ZASPF.

Final report

ISBN: 978-1-86295-462-5
Author: Jeremy Lyle
Environment
PROJECT NUMBER • 2019-016
PROJECT STATUS:
CURRENT

Estimating the biomass of fish stocks using novel and efficient genetic techniques

This project represents the first detailed study exploring the relationship between eDNA concentrations and the biomass and/or abundance of some economically and ecologically important (primarily freshwater) fish species in Australia. The work was conducted over four-and-a-half-years as part of a...
ORGANISATION:
Department of Primary Industries and Regional Development (NSW)

Development of software for use in multi-frequency acoustic biomass assessments and ecological studies

Project number: 1993-237
Project Status:
Completed
Budget expenditure: $251,081.00
Principal Investigator: Tony Koslow
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 29 Jun 1994 - 29 Apr 1999
Contact:
FRDC

Objectives

1. To develop multifrequency-based methods of analysis for an expanding and diverse range of applications in Australian fisheries and associated ecosystems

Final report

ISBN: 0 643 06192 4
Author: Rudy Kloser
Final Report • 2017-09-29 • 11.07 MB
1993-237-DLD.pdf

Summary

The development of the ECHO software has enabled the collection and analysis of large multifrequency acoustic data sets. The data can now be processed in a timely manner (via overlays) to quality assure and interpret underlying acoustic characteristics in the signals. From these analyses we can perform seabed and biomass processing on the individual frequencies. Alternatively the three frequencies can be mixed in a visual display that highlight distinct species groupings.

In the deep water orange roughy fishery the multi-frequency analysis clearly identified the dominant species groupings that occur. These combined echograms show that the community composition around the spawning aggregation is complex and not truly represented in commercial trawling operations. This will have a significant impact on the interpretation of acoustic biomass estimates. The ability to remotely sense the acoustical dominant species composition using multi-frequencies is a major advance in fisheries acoustic research.

The ECHO software has enabled us to develop methods to remotely sense fisheries habitat as well as ensuring high data quality. The software developed in this study was used to process acoustic seabed data obtained from the FRDC South East Fishery research project, Bax and Williams (1998) using simple classification methods. This project and associated software development was used to provide data to the acoustic benthic habitat FRDC project 93/058, Pitcher et al (1998). This enabled the development of enhanced bottom classification methods. We have further developed the processing techniques in this report and demonstrated that the use of multiple frequencies can improve seabed misclassification rates from 27% at a single frequency to 8% at multiple frequencies. This could lead to a major advance in our ability to correctly classify different fisheries habitats and to monitor the long term stability of these habitats.

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