A Review of Acoustic Telemetry Technology and a Perspective on its Diversification Relative to Coastal Tracking Arrays

Automated telemetry systems for tracking ultrasonically tagged marine fauna have diversified in information coding, signal reception, data handling and storage, and deployment architecture in response to niche development among equipment manufacturers. Technologies divide especially along issues of habitat type, spatial scale, and cost. Highly capable designs appropriate to spatial scales from sub-meter resolution to coast-wide migration have emerged. Due to technical constraints (e.g. coding algorithms, frequency) and proprietary interests, tags of one code scheme cannot currently communicate with listening devices from others, sometimes even among devices within a manufacturer's offering. Large-scale federally funded arrays are being designed as observatories to facilitate discovery and experiments and are committed to single-platform technology. Commitment to a single equipment design unifies such arrays but also contributes to inertia that hinders optimization or further development at the local level. Some solutions for cross-equipment communication exist at both the transmitter and receiver ends of the technology. Un-anticipated movement of tagged marine fauna through these arrays can yield important new insights but can also have negative effects on other users of the array. These possibilities should be considered and coordinated through collaborative administrations and as early as the proposal review process. This paper Outlines the needs and constraints to engage scientists with each other and with manufacturers in dialog to mitigate negative effects of diversification without the loss of its benefits. An inability to unify disparate and independent hydrophone arrays risks tremendous lost opportunity to track fish in coastal marine and estuarine settings, as seen in case studies.