• Salinity, Temperature and Depth Archival Tag

Salinity, Temperature and Depth Archival Tag

  • Salinity
  • Temperature
  • Depth

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High performing and long life salinity logging tag for fish and marine animals

For long term fish tagging studies, the CTD tag is one of a kind archival tag due its small size and a salinity sensor in addition to temperature and depth measurements.

Key features

  • Smallest CTD data storage tag on the market
  • Selection of ranges for conductivity and depth sensors
  • Tag holder kit for external fish tagging
  • User defined text on the housing
  • On/off saltwater switch for saving memory

Smallest CTD on the market

The DST CTD Data Storage Tag measures and records salinity, temperature and depth. Size is only 50 mm x 15 mm. It is a self-contained CTD data logger that is user programmable to log the data in the memory at certain sampling interval. The collected data is displayed in a graph and table with a time stamp for each measurement.


DST CTD is designed as a fish archival tag for migration studies of fish and marine animals. It enables scientists to gain valuable information on migration routes and behavioural patterns over a long period of time. The tag needs to be externally attached to the animal, due to the salinity sensor which consists of two conductivity cells. Also available for using the CTD on a mooring or subsea gear.

Depth sensors from shallow water to deep ocean

The tag can be calibrated to 2,400 meters, with tolerance up to 2,500 meters. More shallow water is also available, with a wide variety of ranges: 1m-100m, 5m-500m, 5m-1200m, 10m-2400m

Tag holder kit ensures easier and safer attachment

Due to the salinity sensor, it needs to be external on the animal. A tag holder kit is available for the tags, to make the tagging process easier. It also increases the safety for the fish.

Customer defined text on housing for recapture purposes

For tag and release of animals into the wild the tags can have a customized text on the housing, for recapture purposes. It is important to have the return information when the tags are used on commercially fished species, so that fishermen can return a tag with valuable data to the scientist. Normally there is a reward for return.

Conductivity Sensor

Conductivity cells are part of the logger housing

The conductivity sensor electrodes are located inside a small cup at the end of the logger housing. The pressure sensor for the depth measurements is located at the membrane and temperature sensor close to the membrane.

Custom calibration

For fish and marine animal tagging projects three conductivity ranges are available:

  • 13-63 mS/cm
  • 13-50 mS/cm
  • 3-37 mS/cm

When ordering CTD tags the suitable range is selected.

Saltwater switch

It is possible to purchase the logger with an on/off saltwater switch. This optional configuration saves memory size by only recording data when animal is submerged. This is useful when the logger is used on animals that spend their time both in and out of water.

Don’t know your applicable conductivity range?

The suitable range depends on what the expected minimum and maximum salinity and temperature is in the area where the CTD loggers will be used. Star-Oddi can recommend a range if you provide those information.

SensorsConductivity (salinity),temperature, pressure
Size (Diameter x Length)15 mm x 50 mm
Housing MaterialAlumina (Ceramic)
Weight (in Air/in Water)21g/13g
Data Resolution12 bits
Conductivity RangesChoose between: 13-63 mS/cm, 13-50 mS/cm, 3-37 mS/cm or 0.3 to 5 mS/cm
Conductivity ResolutionRange 13-63 mS/cm: 0.02 mS/cm, Range 13-50 mS/cm: 0.01 mS/cm, Range 3-37 mS/cm: 0.01 mS/cm, Range 0.3-5 mS/cm: 0.002 mS/cm
Conductivity AccuracyRange 13-63 mS/cm: +/-2 mS/cm, Range 13-50 mS/cm: +/-1.5 mS/cm, Range 3-37 mS/cm: +/-1.5 mS/cm, Range 0.3-5 mS/cm: +/-0.3 mS/cm
Salinity RangeDepends on conductivity and temp. range (consult with Star-Oddi)
Salinity Resolution*Range 13-63 mS/cm: 0.01 PSU, Range 13-50 mS/cm: 0.01 PSU, Range 3-37 mS/cm: 0.01 PSU, Range 0.3-5 mS/cm: 0.0005 PSU
Salinity Accuracy*Range 13-63 mS/cm: +/-1.5 PSU, Range 13-50 mS/cm: +/-1 PSU, Range 3-37 mS/cm: +/-1 PSU, Range 0.3-5 mS/cm: +/-0.1 PSU
Saltwater SwitchAvailable upon customer request (DST CTD logic)
Temperature Range-1°C to +40°C (30°F to 104°F)
Temperature Resolution0.032°C (0.058°F)
Temperature Accuracy+/-0.1°C (0.18°F)
Temperature Response TimeTime constant (63%) reached in 20 sec.
Standard Depth Ranges1m-100m, 5m-500m, 5m-1200m, 10m-2400m
Depth Resolution0.03% of selected range
Depth Accuracy+/-0.6% of selected range
Depth Response TimeImmediate
Memory TypeNon-volatile EEPROM
Memory Capacity87,217 measurements per sensor
Memory MangementCustom programming
Sampling IntervalUser specified in second(s) minute(s),or hour(s)
Minimum Measuring Interval1 second
Multiple Intervals OptionUp to 7 different intervals
Data Retention25 years
ClockReal time clock. Accuracy +/-1 min/month.
CommunicationsCommunication Box, wirelss transmission when DST sits in the box. Connection to PC: USB cable.
Attachment Hole0.9 mm (diameter)
Battery Life4 years**
Replaceable BatteryNo

*Based on conductivity full scale accuracy at 24°C.
** For sampling interval of 10 minutes.
Warranty: 12 months.
Specifications may change without notice.