An estuarine observatory for real‐time telemetry of migrant macrofauna: Design, performance, and constraints

Abstract

In 2002, we began tagging macrofauna and established an array of hydrophones in the Mullica River and Great Bay estuary in southern New Jersey, USA, as part of an observatory for the study of migration. The hydrophone array differs from other model telemetry programs in several aspects. The wireless radio‐linked design provides the capability to couple observation in real time with reactive sampling schemes (including mobile tracking), provides for public interaction via frequent updates to a Worldwide Web‐based distance learning program, and saves ship time. However, the wireless design is more amenable to a turnstile‐like acoustic gate than to positioning, and strategic positioning of hydrophones at bottlenecks is favored over continuous contact of transmitters within the large study area. The hydrophone array is supplemented by infrastructure from two existing marine observatory programs focused on physical processes. These are the Long‐term Ecosystem Observatory (LEO‐15) outside the estuarine inlet and the System‐Wide Monitoring Program of the Jacques Cousteau National Estuarine Research Reserve (JCNERR) within the river and estuary. This article outlines considerations in the design and implementation of the array from infrastructure, predeployment survey, and biological considerations through hydrophone placement, maintenance, calibration, and data collection. Further, it presents a comprehensive description of the observatory and study area for reference in works on the biology of those organisms under study. The hydrophone array serves as a unit intended for stepwise extension into other estuaries to assist in our understanding of habitat use and of those species that use estuarine habitat during coastal migration.

Habitat dynamics of summer flounder Paralichthys dentatus within a shallow USA estuary, based on multiple approaches using acoustic telemetry

“…The Mullica River-Great Bay portion of the Jacques Cousteau National Estuarine Research Reserve (JCNERR) (Fig. 1), in southern New Jersey, USA, was chosen for this research because: (1) the estuary is relatively unaltered (Kennish & O'Donnell 2002), (2) the JCNERR provides continuous measures of environmental variables using dataloggers (Kennish et al 2004), (3) the infrastructure for passive ultrasonic telemetry is in place (Grothues et al 2005), and (4) Paralichthys dentatus are seasonally abundant and many aspects of their life history are relatively well known (Able et al 1990, Szedlmayer & Able 1993, Able & Kaiser 1994. This estuarine system includes more than 27 000 ha of open water consisting of Great Bay, Little Egg Harbor, the Mullica River, a few back bays and 2 smaller rivers (Bass River, Wading River).…”

“…In 2003, 30 fish were externally tagged, following Szedlmayer & Able (1993) Tagged Paralichthys dentatus were tracked from 2003 to 2005 using both passive and active telemetry. We defined the passive telemetry approach as an array of wireless, stationary, automated hydrophones (Model WHS_1100, Lotek Wireless) set as 'gates' in the estuary to record the presence of tagged fish within an approximately 500 m radius of each hydrophone (Grothues et al 2005, Sackett et al 2007 (Fig. 1).…”

Sex Differences in Residency of Adult Spotted Seatrout in a Louisiana Estuary

“…later expanded to 60 total receivers in spring 2008 (Figure 1). At the two exit points, receivers were deployed in a gate configuration (Grothues et al 2005;Heupel et al 2006) to monitor emigration and immigration of fish. Specifically, two receiver lines (with two receivers in each line) were deployed in the lower ship channel (hereafter referred to as the "inlet gate") and two single receivers were deployed in the western portion of the GIWW (hereafter referred to as the "GIWW gate") ( Figure 1).…”

An Evaluation of Passive Acoustic Monitoring Using Satellite Communication Technology for Near Real-Time Detection of Tagged Animals in a Marine Setting

“…Using the Iridium satellite network to transmit data has overcome the range limitations imposed by radio (VHF) communications [26] as well as the bandwidth limitations of the ARGOS satellite array. Through the provision of two-way remote communication the user is now able to maintain a closer watch on the status of their acoustic monitoring hardware, analyse data on a more frequent basis, and, if required, obtain real time notification of tag detections.…”