Table 1 Commonly-used tracking devices

Radio tag (Fig. 2.1a)

Mariner Radar (early studies); Advanced Telemetry Systems MM100 Series

Very High Frequency (VHF) or Ultra High Frequency (UHF)

Acoustic telemetry: radio signal (VHF/UHF)

Early pinniped studies. Short range studies. Relocation for data logger retrieval.

6–12 months

80-200 (early studies); 30

Smaller & lighter than Argos/GPS units. No need to retrieve. Can be used to re-encounter specific individuals on a colony for recovery of archival devices (Fig. 2.1a).

Device must be in line-of-sight range of base station(s) and/or mobile receiver(s) to record locations. Signal can be interrupted by terrain.

[31, 32, 36, 37, 184]

GPS Logger (Fig. 2.1a)

Sirtrack F1G

Fastloc ® GPS

Archival

Mainly individuals with restricted ranges (e.g. lactating female otariids during pup provisioning).

3 weeks – 6 months

215

Fast and accurate location estimates. Lighter than telemetry units. Salt-water switch turns the tag off when the animal dives/hauls out to extend battery life.

Must be recovered to extract data, therefore often needs to be deployed in conjunction with VHF transmitter to facilitate re-encounter on the colony. Study limited to specific timescales (e.g. pre-moult/breeding season).

[36, 37, 185]

Argos relay tags (Fig. 2.1c)

SMRU 9000x SRDL; Wildlife Computers Mk10 SPLASH Tag; Sirtrack KiwiSat 101; Telonics ST-10 PTT

Argos

Argos

Very widely used. Long-ranging pelagic pinnipeds in remote locations.

12 months (depending on power options and duty cycle).

370

Can integrate other sensors such as wet-dry, CTD, or accelerometer. Useful in remote areas where no GSM coverage available. Complete data record can be retrieved if tag recovered. Better coverage in polar regions.

Not all locations & dives transmitted. Data often patchy due to interrupted transmissions. Location estimates can carry high spatial error. Fine-scale reconstruction of movement not possible. Argos coverage poor in areas closer to equator.

[42, 43, 106, 120, 186]

GPS relay tags

SMRU GPS SRDL; Wildlife Computers Mk10 SPLASH Tag

Fastloc ® GPS

Argos

Individuals in remote locations with no GSM coverage or prospect of device retrieval.

3-6 months (depending on power options and duty cycle).

370

As Argos relay tag (above). Solar powered option for extended battery life. Fast and accurate location estimates across most of the globe. Can integrate TDR.

Not all locations & dives transmitted. Data often patchy due to interrupted transmissions. Argos coverage poor in areas closer to equator.

[49, 187]

GPS-GSM (Fig. 2.1d)

SMRU GPS Phone Tag

Fastloc ® GPS

GSM (FTP/SMS)

Pinnipeds in non-remote locations (with GSM coverage).

1–12 months (depending on power options and duty cycle).

370

Many power options including solar panel. All dives and locations can be transmitted. Fast and accurate location estimates across most of the globe.

Individual must enter GSM range in order to transmit data (time lag in data retrieval). Not useful in remote locations. If tag detached at sea before entering GSM range data are lost.

[121, 125, 130, 188]