University of St Andrews SMRU Instrumentation
SMRU Instrumentation
Sea Mammal Research Unit

Fluorometer/CTD Oceanography SRDL (Argos)

Explore further how marine mammal behaviour relates to their oceanic environment.
Obtain oceanographic quality CTD casts and fluorescence profiles. CTD/Fluorometer Oceanography Tag displayed on beach rock


  • Oceanographic quality temperature & salinity profiles
  • Combined Valeport CTD and Fluorometer head
  • Near real-time data relay
  • Up to 50,000 full length Argos data transmissions
Our FluoroCTD Satellite Relay Data Logger (F/CTD) incorporates most of the features of the original SMRU SRDL tag. Data relay & location is via the global Argos satellite system, with SMRU's embedded software providing an unbiased sample of detailed individual dive records. Sensors available on this model include depth, temperature, conductivity, fluorometry, light, and accelerometry.

TDR capability

  • As well as transmitting data via Argos, the F/CTD tag also retains a continuous record of depth readings (4 sec sample rate), retrievable by Bluetooth connection should the tag be recovered.
  • The F/CDT also records all individual temperature, salinity and fluorescence measurements (1 Hz) made during profiling.

Technical Specifications:

CTD/Fluorometer Oceanography Tag displayed on beach rock
  • Pressure (Depth):
    • Range: 0 to 2000 dBar
    • Accuracy: 2 dBar ±(0.3 + 0.035%*reading)/°K
    • Resolution: 0.05 dBar
  • Temperature:
    • Range: -5° to 35°C
    • Accuracy: ±0.005°C
    • Resolution: 0.001°C
  • Conductivity:
    • Range: 0 to 80mS/cm
    • Accuracy: ±0.01mS/cm
    • Resolution: 0.002mS/cm
  • Chlorophyll-α (µg/L):
    • Range: 0 - 125
    • Min. Detectable Limit: 0.066
  • Light (mol/m²):
    • Min. Detectable Signal: 1x10-9
    • Max. Detectable Signal: 2000
  • Acceleration (3-axis):
    • Range: ±8g
    • Sensitivity: 64 LSB/g

Dimensions etc:

  • Longevity: up to one year with standard Li-SoCl2 D-cell configuration
  • Size: 11.5 x 10 x 4 cm (excluding antenna)
  • Weight: ~680 g
  • Volume: ~400 cm³

For further technical details, please email

For details of pricing and how to order, please see our Contact & Sales section.
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