GPS archival tag for fish geolocation analysis

DST GPS

GPS geolocation fish archival tag

Overview

Dimensions (diameter x length): 15mm x 46mm
Sensors: acoustic receiver, temperature, pressure (depth)
Standard temperature range: -1°C to +40°C
Temperature accuracy: +/-0.1°C
Depth ranges: 0.1 m to 30 m, 0.1 m to 50 m, 0.1 m to 100 m, 1 m to 270 m, 5 m to 800 m, 5 m to 1500 m, 10 m to 2000 m, 10 m to 3000 m
Depth accuracy: +/-0.4% of selected range for 30 m to 270 m range
+/-0.6% of selected range for 800 m to 3000 m range
GPS receiving radius: From Star-Oddi Fish Positioning Sounder (FPS): ~300 m
From Simrad SP60/SP70/SP90 sonars:  ~4 km distance radius 
GPS accuracy: +/- 370 m optimally
Memory size: 261,741 bytes (GPS code 1-58 bytes, temp-pressure 3 bytes)
Battery life: 3 years
Housing material: Alumina (implantable, biocompatible ceramic material)

Description

The DST GPS is an archival tag for geolocation analysis of fish. The archival tag listens to acoustic signals from specific sounder transmitters that transmit their position. Received GPS codes (longitude and latitude) are stored in the tag‘s internal memory with date and time reference for each measurement. Depth and temperature is also recorded. Upon recapture of the tag the data can be downloaded into a PC computer. For recapture purposes each tag is marked with a custom defined text that informs fishermen how to return the tag.

The DST GPS is supported by the SeaStar software and the Communication Box which serves as an interface between the logger and a PC. The tag connects wirelessly when sitting in the communication box.

The DST GPS is equipped with unique user specified features for optimising the tag's performance when receiving a GPS position:

• With the use of the communication box and the SeaStar software, the user programs the DST GPS with start date/time and sampling interval
• Programming option of up to 7 sampling intervals and number of samplings within each interval
• Option for defining a special interval, making the tag shift to a different sampling interval after each received GPS position
• The DST GPS can be programmed to perform a series of measurements at a detection of a position
• It's possible to choose different intervals for temp-depth and acoustic listening. That way memory partitioning can be customzied according to individual preferences.

After recovering the DST the recorded data is uploaded to SeaStar where results are displayed both in graphic and tabular form. After retrieving the data, the DST can be re-programmed and reused as long as the battery lasts. A set of Communication Box and SeaStar software needs to be purchased with the first order.

When applied on fish and marine animals, the DST GPS can be attached externally or implanted. If applied internally, Star-Oddi can deliver the tag with a plastic tube attached for external identification.  For external tagging, Star-Oddi can provide a tag holder kit. 

Internal tagging of cod and external tagging of Greenland halibut

For more information about accessories please click here.

The Fish Positioning System was developed in co-operation with Simrad (Norway), Marine Research Institute (Iceland) and Institute of Marine Research (Norway).

How the Positioning System works

The DST GPS is an acoustic signal receiving device that can receive underwater acoustic signals containing GPS codes. In order for the tag to recognize the signals they need to come from a sounder transmitting at 26.5 kHz frequency. Star-Oddi offers a portable Fish Positioning Sounder (FPS) for this purpose. FPS sounder can be operated from boats or stationary at fixed location. The Star-Oddi FPS has a transmitting range of ca. 300 m. When used on a boat the resolution of the GPS can optimally be set to 70 m. The accuracy of the GPS code is resolution plus transmitting range, or 370 m optimally. 

Certain types of Simrad sonars operated from vessels can be programmed to transmit acoustic signals to DST GPS tags. The Simrad sonars have a transmitting signal radius of 4 km.

DST GPS records the position of the sound source where the GPS code is received and transmitted, usually from a boat. GPS position is received from a satellite and the signal is sent via an acoustic transmitter underwater. If a tagged fish or animal passes the area within the transmitting range and the DST GPS is listening (according to set interval) for the signal, it records the geographical position of the sounder in its internal memory. Recorded positions along with temperature and depth values can be retrieved after the tag has been recaptured and the data analyzed in the SeaStar graphic supporting software.

Examples of Application

Fish migratory pattern 
General knowledge about migratory route of fish is limited. Information on geographical distribution of commercially interesting fish resources are available, but until present it has not been possible to follow single fish or schools of fish in time and space over great distances. The aims of the GPS Fish Positioning System is to increase knowledge on fish migratory routes, and provide contribution to sustainable management of fish resources.

• Data for improving stock assessment and management
• Data for stock models, accessibility and availability of fish resources
• Behaviour analysis, migration and distribution
• Salmon and anadromous trout and charr, coastal migration

Related links:
View a short animation (mpeg) of the GPS system (5 Mb)
Fish Positioning Sounder (FPS)
Case studies - research objectives
Uknown migration of cod - Results from GPS tags
DST GPS Fish Positioning Article