Science briefs


Photo of Japanese Octobus ballsJapanese Octopus balls

Octopus life cycle loop closed

Fully farmed octopus are likely to be available in Japanese restaurants in the near future with Japanese company Nippon Suisan Kaisha (Nissui) announcing a key innovation to ensure survival rates of artificially incubated octopus. 

Until now, octopus incubated in this way has been plagued by low survival rates in the first 30 days after hatching. But the company says the identification of an aquatic organism that nourishes the growing octopuses makes the successful hatching of 140,000 eggs by artificial incubation significant. The octopuses were hatched earlier this year in the Oita Marine Biological Technology Center in Saeki in western Japan.

The company hopes to be able to ship fully farmed octopuses to Japanese restaurants and retailers by 2020. Full-cycle aquaculture stipulates that eggs used in the incubation process be derived from animals that were themselves conceived by artificial incubation, the Nikkei Asian Review reported.

Word wise

Each issue we will try to clarify the meaning and use of some commonly misunderstood words in fisheries science

'Targets' versus 'Limits'

School of fish illustratoin

‘Targets’ and ‘limits’ are the names for reference points used to guide fisheries management in maintaining the health of fish populations. They are signposts that let fisheries managers know whether a fish population is okay or if they need to take action.

A ‘target’ is the desirable level at which to maintain a fish population while it is being fished – fish numbers remain self-sustaining, or healthy.

On the other hand, a ‘limit’ indicates the point at which a fish population is no longer self-sustaining, given the level of fishing activity. When population limits are reached action is needed to lift the population above the limit and back towards the target.

Fisheries managers have different strategies they can use to ensure fish populations remain at healthy levels, including reducing the number of fish caught or closing an area to fishing until a population recovers.

Fish populations may fall towards their limit as a result of many factors, including overfishing, recruitment failure, loss of habitat or environmental factors such as water quality and temperature.


Documentary sets sights on clearer waters

Work has begun on Clearer Waters, a documentary web series focusing on the key questions that underpin the National Carp Control Plan (NCCP) and the researchers working to find answers.

The series will showcase the huge amount of work going into the NCCP and the key questions the research program is aiming to address.

These include estimating the number of carp in Australia’s river systems and addressing the challenges of potentially using a biocontrol.

Clearer Waters will be produced by NCCP Digital Media, published on Vimeo and embedded on the NCCP website.


New ocean forecasts

Fisheries, aquaculture operators and other marine users can take advantage of a system to avoid danger and make their operations more efficient using a new online forecasting tool. The eSA-Marine system forecasts sea surface temperature, salinity, ocean currents, wind direction and speed for the Spencer and St Vincent gulfs and the southern coast of South Australia.

The system’s maps can help fishers save vessel fuel by indicating the most efficient routes or providing the variables that indicate fish habitats. Similarly, for aquaculture operators, the forecasting system can show optimal routes for towing aquaculture pontoons.

The eSA-Marine system is also invaluable as a search-and-rescue device for its ability to predict storm surges and flooding. The website uses real-time satellite data to capture ocean forecasts ranging from Portland, Victoria, to Thevenard in South Australia’s west, and includes gulfs, shelves and deep waters of the continental slope. This is the first phase of the eSA-Marine ‘now-cast’ and forecast modelling.

The technology has been developed in South Australia by researchers from the South Australian Research and Development Institute and the Department of Primary Industries and Regions South Australia in partnership with the Bureau of Meteorology and the University of Adelaide.

Maps can be accessed online from any computer or mobile device.