15 results
Adoption
PROJECT NUMBER • 1998-343
PROJECT STATUS:
COMPLETED

9th International Conference on Harmful Algal Blooms, 7-11 February 2000, Hobart

The FRDC sponsored 9th International Conference on Harmful Algal Blooms held in Hobart, Tasmania, from 7-11 February 2000, was a resounding success. It was the largest conference on this topic (526 participants from 47 countries) ever held anywhere in the world. A total of 130 talks and 308 poster...
ORGANISATION:
University of Tasmania (UTAS)
TAGS
Adoption
Industry
Industry
PROJECT NUMBER • 1996-352
PROJECT STATUS:
COMPLETED

Aspects of feeding, maturation and osmoregulation in cultured juvenile greenback flounder

Skeletal deformities have been observed in cultured flounder in recent years. At times, high percentages of fish are affected, potentially influencing growth and marketability, and affecting the reliability of the experimental data collected. Many growers taking fish for pilot scale grow-out trials...
ORGANISATION:
University of Tasmania (UTAS)
Environment
PROJECT NUMBER • 2001-044
PROJECT STATUS:
COMPLETED

Establishment of the long-spined sea urchin (Centrostephanus rodgersii) in Tasmania: a first assessment of the threat to abalone and rock lobster fisheries

The pattern of distribution of the long-spined sea urchin Centrostephanus rodgersii over ca. 40 y in the Kent group, Bass St., suggests initial establishment in the mid 1960s with subsequent expansion of populations to its current status as the dominant invertebrate on shallow subtidal rocky reef....
ORGANISATION:
University of Tasmania (UTAS)
Environment
People

Development of an algal bloom monitoring buoy for the Australian aquaculture industry: proof of concept

Project number: 1995-085
Project Status:
Completed
Budget expenditure: $20,000.00
Principal Investigator: Gustaaf Hallegraeff
Organisation: University of Tasmania (UTAS)
Project start/end date: 23 Jan 1996 - 29 Aug 1997
:

Objectives

1. To improve the sensitivity of current algal watch programmes in Tasmanian waters, designed to protect shellfish and finfish aquaculture by means of frequent microscopic plankton analyses

Final report

Author: G.M. Hallegraeff and C. Ashworth
Final Report • 1997-06-25 • 2.06 MB
1995-085-DLD.pdf

Summary

A prototype of an automatic algal monitoring buoy was developed for unattended operation in shellfish and finfish farm waters. The instrument employs novel antifouling and self-calibration strategies (subject to a provisional patent ) based on a battery-powered actuator extending into the seawater medium at 15 min intervals both a light source and a solid state sensor from a protective PVC cylinder. The optical sensor measures both ambient light and the signal from a high intensity LED light source, with separate readings being taken after travelling through an optical fibre reference path (internal standard) and after travelling through a 60 cm horizontal path of natural seawater. The optical system is suspended at 1 m depth (can be varied) from a float with the systems control and data acquisition system located above water.

Financial constraints ($20,000 FRDC budget) prevented us to also implement a radiomodem link to laboratory computer as originally planned. We are now seeking further funds to develop the instrument to a commercial stage (estimated market value per unit Aus $10,000) and extensively test its field performance under a range of environmental and algal bloom conditions.

Tactical Research Fund: managing inshore stocks of southern rock lobster for a sustainable fishery

Project number: 2009-058
Project Status:
Completed
Budget expenditure: $75,000.00
Principal Investigator: Bridget Green
Organisation: University of Tasmania (UTAS)
Project start/end date: 29 Nov 2009 - 14 May 2011
:

Need

There is clearly a concern in the Tasmanian lobster industry about the status of inshore component of the stock. Catch has declined in a number of areas, despite improvements in catch rates. In the Northeast, catch is at record lows, but CPUE has remained stable, which is a possible indicator of hyper-stability or false stability. The apparent stability in catch rates occurs because aggregations containing a major proportion of the population are fished down, as the fleet moves from one area of good catch rates to the next, resulting in a serial depletion of the aggregations, which is masked by the apparent stability in the fishing block. This can result in a very sudden decline in biomass once the entire block is depleted, posing a serious and immediate risk to the inshore component of the stock. There are two potential sources of this problem. Firstly, the scale of the current assessment model, of eight inshore areas (64m) and three offshore areas (>64m) is not be fine enough to detect localised changes in the CPUE or biomass. Secondly there are changes in fishing practices that have increased effort on inshore stocks, and it is unclear whether the extra effort in these practices is adequately recorded in estimates of CPUE. There has been a recent increase in potting effort, commonly referred to as double night fishing, whereby fishers set and haul their pots twice a night, compared to the standard practice of emptying pots once at dusk and/or once during the day. Currently we have no data on the composition of the catch in double night shots, and what proportion of captured lobsters are handled and released, and in fact what consequence this handling has on the overall health of the fishery.

Objectives

1. Determine the extent of declines in the inshore stock by changing the current stock assessment model to assess stocks at a finer scale (&lt
30m and &gt
30m).
2. Assess whether increased effort in double night shots is adequately recorded in estimates of CPUE
include the differences in catch composition, size structure and the effects of handling on growth in assessments.
3. Assess the cost-effectiveness of double night fishing and compare short and long-term benefits.
4. Develop a management strategy evaluation, presenting options based on the results of the study.
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