Since the multiplex transceiver was developed, researchers have confronted new challenges and developed innovative uses for instream PIT–tag monitoring systems.
By allowing up to six antennas to be operated using a single transceiver, the FS1001M transceiver has advanced the ability of instream monitoring to provide insight into fish behaviors that could not have been obtained otherwise (Roni et al. 2012). However, the FS1001M transceiver is not without limitations.
It is based on a firmware platform that is now over 15 years old and has no room for new functions, its cost is still relatively high, and its components were not specifically designed for the demands of instream use.
Ideally, a new transceiver design would include some or all of the following features:
Construction of antennas for FDX PIT–tags is still relatively costly and time–consuming, and the antennas are relatively small for many instream applications.
A major limiting feature of these antennas is the 5 cm air gap that is normally required around the wires to ensure maximal performance. To maintain this air gap, a waterproof housing must be constructed, and this increases the cost, complexity, and footprint of the antenna system.
A transceiver that could operate with little or no air gap would allow for thinner antenna housings, and this would reduce drag, simplify installation, and improve stability during high flows.
Ideally, a new transceiver would allow for larger antennas, which would enable researchers to investigate questions that cannot be addressed with the current equipment.
The cost of instream monitoring will vary, depending on the number antennas used, the transceiver, the power system, and the devices used for data–retrieval, storage, and transmission. However, many projects are constrained by cost, and cost is often the determining factor in deciding what equipment to install or the number of monitoring sites.
Thus both technological and economic improvements are important to future transceiver development if we are to sustain and increase the accessibility of stream monitoring systems to the projects and researchers who need them.