Hudson River Echosounder Surveys

Project Overview

This project uses the SV Clearwater (a educational  and historically-accurate-replica sailing vessel) as a ship of opportunity to collect acoustic data from the waters of the Hudson River (ranging from the NYC area all the way up to Albany).

A scientific echosounder is mounted on the hull of the vessel with the electronics inside the ship.  This instrument measures the backscattered acoustic energy at two frequencies (38 kHz and 200 kHz) from fish and zooplankton (small marine animals) (and other scatterers) which are in the water.  The physics of this system are identical to a depth-finder or fish-finder that other boats have; however we can calibrate this instrument to collect very precise information as to where animals are and how many of them there are! We use other methods (video cameras, fishing catch reports, historical information) to determine what specific species of fish and zooplankton are in the different areas of the river. These data will be used to study the distribution and abundance of fish and zooplankton in the Hudson River and the changes that occur in these populations as you move up and down the river and through time.

The Research Team

SoMAS Associate Professor Joe Warren and graduate student Maija Niemisto are the research team for this project and we’re working with the Captain, crew, volunteers, and staff of the Clearwater organization. Additional support has been provided by the Hudson River Foundation. Joe is a bioacoustician who is interested in improving our ability to convert acoustic backscatter data into biologically meaningful information. Maija’s thesis project will be based on the data collected during this cruise. Other scientists or anybody else who is interested in assisting with this project should feel free to contact Joe for more information.

As you can see in the picture to the right, video methods for finding fish would be very difficult in this region due to the high levels of turbidity (suspended sediments).

 

Fish and zooplankton

One of the largest challenges in this project will be accurately determining what animals we are measuring with our echosounder. We can use the different levels of scattering at the two frequencies on our instrument to determine the broad category that the organisms belong to: small plankton, small fish, or large fish.  But there are many objects in the water column that will scatter sound and don’t fit into those categories so we’ll be using additional methods (fishing, net tows, information from local residents and scientists) to supplement our data.  In fact, if you have caught any fish in the Hudson River, please feel free to send that information (date/time, location, and  number and length of species caught to us.

Data Availability

Data are collected anytime the ship leaves port, but due to the size of the files involved (100s of MB every day), they are transmitted to shore ittermitently. These files are contributed to an online repository (part of the National Geospatial Data Center) where they are available to any interested parties. If you have any questions regarding the data, feel free to contact us.