Presenting Zack Tracks!
Zack Darnell. a graduate student down here is spending 3 weeks out of the next few months living alone on my boat while he monitors his equipment. Follow his twitter @zackdarnell or in the sidebar here.
Here’s a brief summary of what he’s doing:
In tidal estuaries, spawning blue crabs migrate using ebb-tide transport. They swim to the surface on ebb tides and ride the tidal currents seaward. This is driven by an endogenous circatidal rhythm in vertical swimming behavior. I’m interested in how spawning crabs migrate in non-tidal estuaries, like the Albemarle-Pamlico Estuarine System (APES). The APES is essentially non-tidal with most variation in water level and currents being driven by winds. So, how do the females migrate seaward? To help answer this question, I will be tagging ovigerous blue crabs with depth-logging tags and tethering them on stainless steel tethers about twice as long as the water depth. The tags log depth every 6 seconds, so I will be able to capture even short-duration ascents into the water column. I’ll also deploy a CTD and a current profiler in the center of the array of tethered crabs to measure water currents, salinity, temperature, and water depth. The goal is to correlate vertical swimming behavior with physical parameters of the water column to determine what cues are being used by migrating sponge crabs. I’ll be running these experiments in West Bay (southern end of Pamlico Sound) in about 8′ of water. To ensure that the instruments do not get vandalized, trawled up, or stolen, I’ll be living on a small boat nearby for 5 days to a week at a time. The boat is a 20′ Wellcraft with a homemade PVC and tarp shelter. I’m hoping to start the first deployment on Monday, June 29.
~Southern Fried Scientist