Underwater Tagging Equipment UTE - For tagging fish in deep water

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Underwater Tagging Equipment - UTE


The Underwater Tagging Equipment gives the following advantages:

  • The UTE is specially designed for remotely tagging deepwater fish that cannot survive changes in pressure when brought to the surface for traditional tagging and release.
  • It prevents the need for hauling the fish to the surface for tagging and release
  • Less time is spent in handling the fish, which leads to increased tagging efficiency
  • Fish is tagged in its natural environment, avoiding stress factors as pressure and temperature changes and therefore decreases tagging mortality


Star-Oddi has developed Underwater Tagging Equipment (UTE) for tagging fish down in the oceans. Being the first company to offer equipment for this purpose makes Star-Oddi a pioneer in the technology of tagging fish underwater. The equipment has revolutionized methods for fish tagging and fisheries research. The equipment is inserted in the ship's fishing trawl net to perform the operation underwater. 

The UTE opens new fields in fish research, enabling researchers to tag deepwater species that have not been previously tagged, and can not survive being brought to the surface. The UTE can tag fish at depths down to 1000 meters. Recapture of tags released from the UTE is dependent on fisheries. The tags will help scientists to learn more about the behavior of various fish species, and provide information on fish migration, distribution, feeding behavior, vertical and horizontal movements and stock assessment. Data from the tags will further provide valuable information for the management of the fishery resources and help with decision making. Both electronic tags (measuring temperature and depth), and dummy tags, can be used in the UTE.

In order to use the UTE, a vessel equipped with a fishing trawl with cable wire is required. The control unit in the UTE is attached to the cable wire. The UTE is placed at the end of a fishing trawl and launched into the ocean. Fish in the trawl are diverted into the UTE, where they are tagged and released. The researcher controls all tagging from a PC computer onboard that is linked via the cable wire to the UTE. The UTE is equipped with four underwater cameras, enabling the user to view (from different angles) on-line video images from the UTE.

The UTE is developed in co-operation with the Marine Institute of Iceland, Grandi (a large fishery company in Iceland) and the Research Council of Iceland.

The tagging process

1. As a fish is inside the trawl and approaches the equipment at the cod-end of the trawl, it is enclosed by a grid which diverts the fish into tagging place. The fish is viewed through the onboard video camera, and the tagging gun is moved into position. All functions are controlled using the application software.
2. A knife makes a small incision into the skin of the fish for the DST tag to be pressed into its body cavity. Although the tag is inside the fish a small hose hangs outside to allow its identification.
3. After tagging the fish it is released through a channel in the device and out into open water. Each fish can be tagged in just a few seconds, much quicker than existing methods. The operation is controlled by the scientist sitting at a computer onboard the vessel.

Tagging cruises

In the development process, a few experimental cruises were conducted where redfish (Sebastes mentella) was surfaced after the tagging procedure by UTE. The purpose was to analyse the success of the tagging.

In October 2003 there was a successful tagging cruise, when 200 redfish were tagged at 500m depth in the Irminger Sea. Read more about the cruise.

In June 2004, the Marine Research Institute (MRI) in Iceland, along with a team of experts from Star-Oddi, tagged 552 redfish at depths from 500m to 800m, using the Underwater Tagging Equipment (UTE) made by Star-Oddi.

In June 2005 MRI were able to tag 1024 redfish in a successful cruise. Thereof, 49 fish were tagged with electronic tags DST micro, measuring depth and temperature. Tagging depth was 500-800 m.

In August 2006 MRI tagged 646 redfish, thereof 38 with electronic tags DST micro.

In July 2008 MRI tagged 336 redfish, thereof 15 with electronic tags DST micro.

Total of 2758 redfish have been tagged. 62 tagged redfish have been recaptured since the first cruise in October 2003. One fish was recaptured 7 years after tagging. Below is a map with locations of release and recapture sites.  

Technical Specifications

Size (dimensions) H x W x L100 cm x 140 cm x 300 cm
Weight (in air/in water)in air: 650 kg
Pressure tolerance100 bar/1000m
CommunicationsStandard cable wire transfers signals between ship and UTE. This includes measurements, video from four underwater cameras, and the control of all tagging functions.
Pressure range0 to100 bar
Base materialStainless steel, low corrosion
Video cameras4 video cameras (black and white)
LightHelical bulb. Light filter optionally attached, allowing only red light through in order to protect the eyes of the fish.
Operational pressure/depthUp to 100 bar/1000 meters
Hydraulic pressure0 to 250 bar
UTE control unitPPC (Programmable Process Controller) Communication unit.
Light and video switching actuators
PC control unitStandard PC
UTE tagging software with video card
Communication unit, composite video output for VCR
Power supply for charging the battery container
Tagging gunRemotely controlled, can be moved in two directions
Capacity for tags59 tags
Tags appliedDST micro dummy tags
DST micro electronic tags, measuring temperature and depth
Size of tags (diameter x length)8.3 mm x 25.4 mm (plus the plastic tube/spaghetti tag)
Measured parametersTemperature
Inclination (pitch and roll)
Battery container lifetime4 hours (rechargeable)

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