NexSens CB-100 data buoys assist Lake Erie walleye research

NexSens CB-100 data buoy deployed in Lake Erie

Recent upgrades to a Lake Erie monitoring buoy and addition of a second buoy will help the Ohio Department of Natural Resources better understand what causes fluctuating walleye hatch sizes. Declining spawns of walleye in the lake have been a topic of concern for many years, as the region’s multi-billion-dollar fishing industry relies heavily on the popular fish.

Last year, the ODNR’s Division of Wildlife Sandusky Fish Research Unit began investigating how lake current influences the hatch sizes. Biologists at the research unit suspect that inshore currents can lead to larger hatch sizes, as they deliver the larvae to nearshore areas, which are warmer and more hospitable to the young fry. Conversely, offshore flow can send the larvae to cooler, less productive areas deeper into the lake.

NexSens Technology had assisted last spring in the design and deployment of a current monitoring data buoy that was positioned near the lake’s reefs where walleye spawn.

The buoy has now been replaced with the newly-released NexSens CB-100 coastal data buoy. Additionally, the on-board data logger, which was previously a standalone SDL500 submersible data logger, has now been upgraded to support real-time cellular telemetry. This allows Division of Wildlife researchers to monitor continuous information from the buoy without having to travel to the site to download data directly.

The ODNR has also added a second CB-100 data buoy for monitoring within a separate lake reef. Both buoys are equipped with NexSens T-Node temperature strings and are also connected to SonTek Argonaut-XR acoustic Doppler current profilers mounted on the lake bottom. These units are capable of measuring water velocity in 3D over a range of up to 40 meters.

The Doppler unit connected to the new second data buoy is mounted within a Sea Spider fiberglass seafloor platform, which secures the Doppler unit to the lake bottom and protects it from trawling. The Doppler that was deployed last year is instead mounted within a custom instrument sled.

Connection to each of the seafloor Doppler units is possible through the T-Node temperature strings, which utilize sensorBUS pass-through technology to allow for interfacing with additional devices anywhere along the string.