aquaculture

Marron (Cherax tenuimanus) is a very large freshwater crayfish native to the main permanent rivers in the forested, high rainfall areas in the south west of Western Australia. They can be farmed in other areas of Australia, but they prefer cooler waters. Marron can grow up to 2 kg (4.4 lbs). Market prices them at about $A 30 – 40 kg. Marron are similar, but larger than the yabby. Marron is a luxury product highly prized by chefs which attracts much higher prices than yabbies or redclaw crayfish.

Health testing of yabbys has revealed very few diseases in farmed and wild yabby populations. These include microsporidiosis which was probably introduced with illegal imports of yabbys from the eastern states; and a small undescribed virus. Testing for crayfish plague fungus (Aphanomyces astaci) since 1989 has supported the claim that this devastating and internationally reported disease is not present in Australia

Marron are increasingly being farmed and husbandry techniques are developing rapidly. Informal information is being shared at the Crayfish Information Network.

The Department of Fisheries, Government of Western Australia, has published information about farming marron. They even advise on how to keep Marron in backyard pools.

Because of poor planning, improper construction, or lack of proper management, many Mississippi lakes and ponds are relatively unproductive. A pond that consistently produces good catches of fish is a result of proper planning, construction, and management. The purpose of this publication is to encourage Mississippi landowners to plan, construct, and manage their ponds and lakes properly for recreational fishing.

The information contained in this document is applicable to other locations – both within the US and beyond.

A good pond depends on location, design, construction, stocking, and management. After the pond is completed, success or failure depends on the landowner’s using necessary practices to establish and maintain good fish populations. Proper stocking of the right species and number, a balanced harvest of mature fish, proper fertilization, water quality management, and aquatic weed control are basics the pond owner should understand. Many unmanaged ponds could produce many more pounds of fish than they now produce if good management practices were followed. The annual harvest of fish can provide hours of recreation, pounds of nutritious food, and supplemental income.

Siamensis Group was formed by a group of people who met online. Their love of freshwater fish and aquatic plants brought them together to make their dream come true – a website about Thai fish and their husbandry. Siamensis Group is an independent non-profit group working to save Thai freshwater fish, aquatic plants, and their habitat.

They note there seems to be fewer and fewer clean bodies of fresh water for fish to live. Illegal deforestation, damming, and polluted water from factories represent a direct impact to the rivers and ponds the fish and plants called home. Some fish species are now declining at a very fast pace; some are feared already extinct.

The Siamensis Group’s ultimate goal is to make sure the continuous existence of Thai fish and plants. They believe that if people are aware of what aquatic life is in the water around them, they would like to protect it. The main part of their website is dedicated to reports from their survey trips. In the survey reports they note what species of fish and plants were found. If possible, they re-visit the location to collect more data and to update the current situation. Most of the reports are written in Thai, some English translations can be found at the bottom of the page. There are beautiful photographs on all pages, so even if you can’t read in Thai, the pages are well worth a look.

The strength of Australian aquaculture lies in its disease-free status and reputation for providing clean, green products. Many serious infectious diseases, which limit aquaculture production overseas, remain exotic (foreign) to Australia. However, experience overseas shows that as fish production intensifies, the incidence of diseases also increases.

Exotic disease outbreaks are a significant threat to Australian aquaculture. In a suspected outbreak, disease control is the responsibility of State fish health authorities, who are supported by the CSIRO Australian Animal Health Laboratory (AAHL) Fish Diseases Laboratory (AFDL). This facility is managed by CSIRO Livestock Industries.

Finfish diseases, especially salmonid diseases, have been studied for many years and most can be tested for at AFDL. However, as Australians begin culturing different species, new diseases are likely to occur.

Fast and accurate disease identification is crucial in containment of a disease outbreak. Many fish diseases are manifest by similar disease signs such as skin lesions, sluggishness and loss of balance, condition and appetite. Laboratory tests often provide the only means to diagnose a disease with certainty to ensure that appropriate disease controls are implemented.

The AFDL is an integral part of CSIRO’s Australian Animal Health Laboratory (AAHL), a national facility specialising in research and diagnosis of animal and fish diseases, especially exotic diseases. This means AFDL scientists are ideally placed to diagnose both exotic diseases and newly emerging diseases.

As a diagnostic and research laboratory, AFDL has four major roles:

* disease diagnosis and identification of infectious agents (pathogens)
* development of diagnostic tests for exotic diseases
* training and technology transfer
* export certification testing and health surveillance.

In CSIRO AAHL’s microbiologically secure research facility, exotic disease agents can be studied without risking accidental release to the external environment. The CSIRO has released a list of diseases of concern to aquaculture.

The crucial roles women play in aquaculture production have been explored at the Institute of Aquaculture, University of Stirling, Scotland.

For example in Cambodia, higher yields are obtained from fish ponds managed mainly by women. In Thailand and China, they often bear the sole responsibility of farm and aquaculture production because of male migration to cities. However, women’s contribution to aquaculture is often unrecognised and the real benefits from their involvement in the activity are not objectively assessed. This is surprising given that small-scale aquaculture development is increasingly considered as a means by which the livelihoods of the poor, including women, could be improved.

The results contained in a final project report by: Brugere, C., Kusakabe, K., Kelkar, G., Felsing, M. and Muir, J.F. (2001) Women in Aquaculture. Project FWG 03/99, Asia Pacific Economic Cooperation, Singapore; is fascinating reading.