Tracking Aqautic Vertebrates in Dense Tropical Forest Using VHF Telemetry
                MTS journal Vol 32, No. 1 p. 82-87 (by Anthony R. Martin et al)

Tracking :

• usually carried out both by hand (usually from a small outboard-powered alumnium boat) and using automatic, scanning, directional receiving stations situated above the forest canopy
• thirty four botos (Amazon river dolphin) and two caiman were fitted with 1mW output VHF transmitters in the frequency range 173-174 MHz
• Transmitters cold be detected by the fixed receiving stations were variable from 100 m to 6,000m, dependent on the amount of intervening vegetation and the orientation of the transmitter antenna.

• provided knowledge of the whereabouts of most tagged animals for most of the time
• Despite the warm, poor quality water in which botos live, wounds on these animals healed very quickly and with no apparent infection.
• Short term Reaction of the Dolphins: ovservations of tagged animals in the first week after release did not reveal any outwardly abnormal socail activity or other behaviour. Newly tagged animals were seen in large and small social groups, swimming and diving as normal and interacting normally with the observation boat.
• Long term Reaction of the Dolphins: No long term behavioral reactions to capture and tagging were recoreded, nor has tagging caused any obvious health risks either before or after release of the transmitter from the animal.
• All ages and reproductive status were captured, marked and released

• very dependent on manpower for monitoring and data-collection
• radio tracking of aquatic animals in low-latitude forests are very poor
• dense tropical rainforest blocked the signals and also animals were often caught in the receiving stations on top of the trees
• requires huge resources in terms of finance and manpower to service the transmitter and receiving stations and to collect tracking data

radio telemetry studies of wild animals is that the tagged individuals are representative of the population as a whole