Newsletter // Issue 7 // October 2010 // 

Acoustic training of fish

In traditional fisheries there is great energy consumption required to catch fish with trawls and high risk of bycatch when using longline fishing gear. The question arises whether it might be feasible to use knowledge about fish behaviour, social learning and acoustic training to aggregate fish and entrap with minimal energy requirement and with the possibility of sorting out and releasing all unwanted bycatch without mortalities?

Fish are most sensitive to low frequency sounds and can detect sounds coming from several km distance. However, the fish do not come to the sound source unless being rewarded, for example, with food. A study was carried out by Bjorn Bjornsson at the Marine Research Institute of Iceland with the aim of finding out how long time it would take to train cod to come to a specific feeding location as a response to a sound signal. Furthermore, to find out how much this training time could be reduced in the presence of "teachers“. The experiments were carried out in a sea cage in Northwest Iceland.

Two feeding platforms were placed inside the cage, one on each side. Pipes were used to deliver the feed from shore to each platform with a seawater pump. Online underwater video camera and sound source were placed at each of the feeding platforms. As a sound source a special buoy was developed by Star-Oddi, a product named FishCall.

The results showed that it took one week to acoustically train 20 naive cod, but less than two days to train 19 naive cod accompanied with one trained cod. It is hypothesized that acoustically trained fish released in the open sea will swim between two feeding stations equipped with FishCall, leading a school of wild fish into a trap and thereby facilitating capture or ranching of wild fish. Read the full scientific article here.

FishCall - new product release!

FishCall is a submersible acoustic transmitter (sounder) developed for sending low frequency sound to attract fish to the sound source. It is made of watertight plastic cylinder containing transducer, two 12V batteries and electronics required to start and program the sound signals. The user can define transmitting range to be from 200 Hz to 250 Hz. It is also possible to define intervals of sound transmissions. The main objective with the FishCall was to develop a new and environmentally friendly fishing technique where sound signal is used to attract fish to a trap, or the sound source platform

With the unique technology of a powerful low frequency sounder it also opens up doors for various other applications that marine biologists may have. See technical specifications.

PatternFinder data analysis software -     now available!

Star-Oddi has launched PatternFinder, a new advanced graphics data analysis software.

With help from our customers we built in the core features in PatternFinder as desired by scientists. Our main goal with PatternFinder is to save your time and money by making data analysis faster, more efficient and easy.

In PatternFinder you can analyse data from one or several loggers, just one sequence or several sequences at a time, combined in one graph. PatternFinder is the perfect tool for analysing large amounts of data that otherwise would take a long time to process. 

PatternFinder works seamlessly with our data loggers and supporting softwares. You can also import text format data from other loggers and systems and export result data to other softwares. Please  look up PatternFinder on our website and contact us for more information. We have also just added the PatternFinder tutorials

Swimming in Iceland

One of the most popular activities in Iceland is taking a dip in the numerous swimming pools that can be found in every part of the country. For centuries, Icelanders have enjoyed bathing and swimming in the geothermal water which originates from Iceland’s rich source of hot springs. Swimming is an important part of Icelandic culture and has been a part of the school curriculum for several decades.

Despite the cold climate, most of Iceland’s swimming pools are outdoors, but are kept at a comfortable temperature, around 29°c. In addition to providing a relaxing effect, bathing in the hot water while breathing fresh air is also believed to have a good effect on people suffering from various health conditions such as asthma and heart diseases.

The picture above is of Laugardalslaug, the first concrete pool in Iceland. It was built in Reykjavik in 1908.

Data Storage Tags-DSTs

Star-Oddi has been manufacturing and developing DSTs since 1993. The data loggers are used for various studies, such as fish tagging, fishing gear studies and oceanography. You can find our whole product range here. The following sensors are available:

Star-Oddi | Vatnagardar 14 | 104 Reykjavik | Iceland | Tel: +354 533 6060 | Fax: +354 533 6069 | Contact  | www.star-oddi.com