Youth Education Report - JCAA News (November 2003)

An Introduction To The Rutgers University StriperTracker Program

by Thomas Grothues, Assistant Research Professor

(from Jersey Coast Anglers Association November 2003 Newsletter)

Estuarine water is often so murky that neither the habitat nor its inhabitants are readily visible, and estuarine fish habitat can be easily dismissed as unimportant by those not educated to its value. Anglers learn of estuarine value from hours spent fishing and educate themselves on habitat function through their own observations. Scientists do likewise by standardizing catches to effort. There are, however, practical limits to what even dedicated recreational and commercial anglers, managers, and scientist can learn from the capture of fish. The Rutgers University StriperTracker program seeks to tackle simultaneously the issues of education on habitat, value to the community, and fundamental research by providing a view into estuarine use by striped bass. This beautiful fish invokes an emotional following and provides substantially to New Jersey’s economy; it is, therefore, an appropriate ambassador of the estuaries and helps bring community attention to other aspects of marine research in New Jersey. The program makes the movement of fish “visible” to the public in an engaging way by allowing them a vested interest in the scientific exploration of the estuary. To that end, the StriperTracker program couples research and outreach by displaying movements in near real-time of transmitter-monitored fish that have been “adopted” by classrooms, businesses, and individuals.

StriperTracker was hatched from a challenge by the Sloan Foundation to move monitoring of marine life into the 21^st century, on par with the advanced techniques used to study physical oceanography and weather. In 2000, the Sloan Foundation established the Census of Marine Life program (COML), meant to provide a push towards tallying all marine fish and such animals as squid and marine mammals. Like putting a man on the moon, the challenge was meant as much to spur development in marine biology, including the development of technological and statistical tools, as it was to meet the worthwhile goal of counting animals. Initial grants from the Sloan Foundation provided for several high-risk, short-term projects to act as feasibility studies for the technologies that could be used for questions that demanded synoptic (wide-scale all at the same time) sampling. While these projects proved to be highly successful, they exhausted that foundations available funding. The job of doing further high-tech monitoring now relies on funding from other sources. Dr. Fred Grasslee, Director of the Rutgers University Institute of Marine and Coastal Sciences, envisioned stepping up to the plate through the monitoring of fish as a compliment to the Institute’s physical ocean monitoring program, a portion of which occurrs at the Marine Field Research Station (RUMFS) in Tuckerton, NJ. Funded by a grant from NOAA, RUMFS director Dr. Kenneth Able and myself implemented the idea in 2002 with a twist, public interaction. By working in conjunction with Dr. Mike Deluca and Janice McDonnell of the Jacques Cousteau National Estuarine Research Reserve (JCNERR), we established an array to monitor striped bass in the Mullica River/Great Bay estuary with near real-time internet posting for use as a distance learning tool. The program, StriperTracker, is now a model program for applied science with public interaction and has generated considerable interest. It has also generated a great deal of data useful for understanding striped bass and their dependence on the Mullica River/Great Bay Estuary and other estuaries.

StriperTracker functions through several steps. The first, fishing, is the best part. Striped bass are taken in the study area by hook and line, which provides suitably-sized fish in better condition than gillnetting or trawling. The second stage is the surgical implantation of acoustic transmitters (tags) through a small incision near the fish’s vent, accomplished under general anesthesia and closed with degradable stitches. The tags are about the size of a lipstick case, and contain a tiny speaker and a battery to power them for two years. Each tag produces a unique code burst every 5 seconds. The sound is ultrasonic, meaning that it is not detectable to people or most species of fish, but loud enough to be heard by tuned underwater microphones (hydrophones) from a distance of a quarter mile or more. In the third stage, the fish swim free but the tag is detected by a series of hydrophones anchored throughout the Mullica/Great Bay system. Upon hearing a tag, the hydrophones radio the individual code to a logging receiver, which records the fish’s identity, date, time, and which hydrophone sent the code. In the final stage, data from the recording receivers are downloaded to a computer, processed, and posted to the internet at http://www.stripertracker.org. A running history of an individual fish’s visits to listening stations can be accessed through interactive graphics. Likewise, the history of a particular listening station in terms of all tagged fishes that visited it is accessed through an interactive map. These histories will soon be joined with those of physical parameters (temperature, salinity, pH) provided by the JCNERR’s physical monitors. The accessibility of these real data is integrated with lesson plans on hypothetical scenarios for classroom use.

Interaction and education in the StriperTracker program goes beyond browsing of the web page; it is distinctly two-way. Resource managers, recreational anglers, schools, and others can benefit from the program’s information; the program, in turn benefits from the knowledge base, financial support, and fish capture by recreational anglers, their support industry, and schools. Anglers donated many of the striped bass caught so far during the spring run at Graveling Point, and the local knowledge of Dave Messerschmitt and Bruce Bertino has helped put us on more fish. Several of the fish have been “adopted” by clubs and organizations, helping in the purchase of additional acoustic transmitters at $267 each. Sponsors are acknowledged on the website with their name and a web link that is posted with the profile and picture of the fish that they adopted. Sponsors thus show that they care, and encourage business from others who do. Adoption by science classes helps students develop a tangible interest in science. Adoptions increase the number of tagged fish, and thereby the measures of confidence in observed patterns and replaces tags lost when fish naturally die, are caught, or leave the system. That point usually spurs the inevitable questions: when do they leave the system, how many leave, and what then? These are among our questions as well, and we are beginning to answer them.

As with other technology-dependent projects, it is prudent to start small, at the local scale, and then build on successes and learn from mistakes when going to a larger scale. A question that we can ask on the small scale is, “How long and where do individual striped bass use the Mullica/Great Bay?”. Next we ask, “How often do they return?” and when we move to the largest scale we expand the equipment placement to include other estuaries and ask, “Where else do they go and how often?” and “Are they all part of the same population, with environmental impacts spread throughout?”. The first short term questions help place a value on different specific aspects of the estuary, such as its characteristic salinity, seasonal temperature cycle, depth, proximity to the coastal ocean, and perhaps helps in determining the size of a local population. In this, even the rate of loss of tags from the system is potentially valuable information. An immediate application to this kind of data is voiced in the concern of anglers who ask about the safety of eating striped bass despite government warnings on PCB levels: “Are fish from this clean system likely to be tainted?” If it turns out that they are resident, one might answer “No”. If, however, they use different estuaries, this will be more difficult to answer. We’ll see what the data shows in the next few years.

We have been surprised by the extent of movement displayed by stripers in the program thus far, and have detected no permanent residents. All five of the fish tagged in fall of 2002, at the beginning of the tagging phase, left the estuary by November 27^th, heralding a brutal winter. Since then, two returned. Both were detected in the vicinity of Little Egg Inlet and within two days were detected at Chestnut Neck, but they didn’t linger. Fish tagged in Spring moved within a day or two from Graveling Point to as far as Lower Bank; some tarried there for weeks taking up almost permanent station while others quickly turned back to the ocean after an initial trip up the river. Tracking from a boat also revealed use of the Bass and Wading Rivers. All of the spring-tagged fish left the estuary by June, but some are occasionally detected near the inlet. We continue to monitor for their return in summer and fall, and we will continue to tag fish while we can.

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