TECHNOLOGY AREAS: Materials/Processes, Electronics

ACQUISITION PROGRAM: N45, SPAWAR

OBJECTIVE: To develop a radio-activated, remotely triggered device that would release a tag package (archival and/or satellite-linked tags) attached to a marine mammal (or other large marine animal). The remote release device (RRD) would release the tag and enable it to be recovered without the need to recapture the tagged animal.

DESCRIPTION: Small, sensor-equipped and microcomputer-driven tags that may be attached directly to large marine animals have led to a wealth of information on the behavior and distribution of marine mammals, and investing in tag development, testing and evaluation is an important Navy S&T focus area. The Navy is required to comply with environmental legislation that protects marine mammals. Information on marine mammal distribution and behavior directly informs required environmental compliance documentation and mitigation measures for Naval training and operations. Archival tags that record behavioral and environmental variables have been the backbone of marine mammal tagging efforts since the mid-1980's. They provide detailed time series data often sampled every few seconds; however, recapture of the animal is typically necessary to recover the tag and retrieve data. Recapture of some marine mammals is not possible, only possible at certain times of year, for others it is always very difficult, all of which limits the number of animals and species that can be tagged. Further, the stress of recapture is probably better avoided. Recently, satellite-linked tags have been developed that record information on an animal's location, dive behavior and environment, summarize the data and transmit it back to researcher in near-real-time via the Argos or Iridium satellite systems without the need for recapturing the animal. However, these tags are expensive and the slow data transmission rates for satellite communication necessitate the transmission of summarized data which limit the type of questions that can be addressed. There is a need in the field for a cost-effective device that enables investigators to retrieve archival and/or satellite-linked electronic tags, which will significantly increase the numbers of animals and species that can be investigated and greatly enhance our understanding of this group of animals.

To improve the amount and quality of data recovered from marine mammal electronic tags , the U.S. Navy is interested in developing a remotely triggered self-detaching recoverable unit. Corrosive links attached to tags that are glued to animals have been used previously, but not knowing the exact time of the release is inconvenient and decreases the probability of tag recovery. A radio triggered device could be released by investigators when animals are sighted. The tag package (archival or satellite-linked tag attached to the animal by a RRD) could be released without necessitating the animal's recapture. Each recoverable tag and RRD attached to the animal should have a unique and specific radio frequency and should be activated by a small handheld transmitter with a FCC approved coded radio signal and a transmission range of 2 � 3.5 km line of sight to the tagged animal. The RRD requires a receiver with a rechargeable or replaceable battery and antennae. To survive extreme pressures and hydrodynamic drag experienced by diving animals, the RRD receiver should be a small and lightweight electronic package capable of accepting tag packages up to 370g, good to a depth of 1500-2000m, battery life good up to 1 year, and adaptable to secure to various mechanisms of attachment to the animal (glue to pelage, suction cups, more invasive).

PHASE I: Provide an initial design and development effort that demonstrates scientific merit and capabilities of the proposed components (transmitter, receiver, release platform) and manufacturing processes for making integrated radio-triggered receiver and release platform or RRD.

PHASE II: Fabricate and field test prototype RRD system including small handheld transmitter (up to 7 inches in length, 3 inches wide, 1 � inches thick with 7 to 10 inch antenna) powered by rechargeable battery, receiver (maximum 0.625 inches thick, 1.75 inches wide and 2.00 inches long) with antennae attached to adaptable size plate (starting size - 4 inches long, 3 inches wide) to carry tag package, and base plate (starting size - 4 inches long, 3 inches wide) that attaches to animal. Specific properties of interest include dimensions, weight, and materials that are conducive to use with marine epoxies and other current marine mammal tag attachments. Prototype unit should be field tested (leading to remotely triggered release and tag recovery) on any marine mammal with any commercially available recorder that includes at minimum time and depth, operating for a minimum of one day.

PHASE III: Based on Phase II experience modify and produce fully integrated Remote Release Device with handheld transmitter, receiver device to carry a tag package (archival and/or satellite-linked tags) that is a self-detaching recoverable unit.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Successful development of the RRD will enable investigators to apply a RRD and tag package to animals that otherwise would not be tagged due to an inability to recapture, greatly increasing the amount of data recovered from tags. The product will significantly decrease the loss of expensive satellite-linked dive recorders, and significantly increase possible numbers and species that can be tagged.

REFERENCES:
1. Fedak, M.A., Lovell, P., & Grant, S.M. (2001) Two approaches to compressing and interpreting time-depth information as collected by time-depth recorders and satellite-linked data recorders. Marine Mammal Science, 17, 94-110.

2. Fedak, M., Lovell, P., McConnell, B., & Hunter, C. (2002) Overcoming the constraints of long range radio telemetry from animals: Getting more useful data from smaller packages. Integrative and Comparative Biology, 42, 3-10.

3. Myers, A.E., Lovell, P., & Hays, G.C. (2006) Tools for studying animal behaviour: validation of dive profiles relayed via the Argos, satellite system. Animal Behaviour, 71, 989-993.

KEYWORDS: tag, transmitter, receiver, bio-friendly materials, remotely detaching