Early Detection of Invasive Species – Zebra Mussel Veliger Analysis

Many freshwater lakes and rivers are being assaulted by invasive species of plankton and other organisms. These invaders are brought into water bodies by ballast water from ships and on the hulls of boats (both commercial and recreational). Introduction of invasive species can cause serious issues to an ecosystem.

Of particular concern are invasive mussels, especially in North America, and their rapid spread to other bodies of water. Because these mussels are so prolific, early detection is critical. Monitoring for larval stage mussels, or mussel veligers, is preferred. Detection of veligers shows the initial presence of the species, when it is possible to take certain steps to slow down their spread.

Zebra Mussel Veligers imaged by the FlowCAM XP

Unfortunately, the veligers are so small (50-250 µm) that they can only be seen through a microscope. Adding to this problem is the fact that in early stages, the veligers will be present in very sparse amounts, meaning that a large volume of water needs to be analyzed through a microscope in order to spot them early.

Using a FlowCAM you can process a significantly larger amount of sample than you can with microscopes. Plus, the FlowCAM images and analyzes a moving stream of sample. This means you’ll be able to detect very sparse populations in a very short amount of time.

The FlowCAM can also be equipped with a cross-polarized illumination option to help you easily distinguish mussel veligers from other organisms. Because their skeletons are calcareous, they will exhibit birefringence under cross-polarized light.

Schematic of the FlowCAM with cross-polarized illumination option

The image below shows all particles found in a lake sample when imaged using cross polarization, sorted in VisualSpreadsheet by aspect ratio. You can clearly pick out the veligers based upon gray scale intensity from similar shaped particles (detritus, Coscinodiscus, etc.).

Zebra Mussels Imaged with Cross-Polarized Illumination

Download the Application Note >>


National Park Service Quagga Mussel Blitz

Lake Powell is the second largest man-made reservoir in the United States. Located on the Colardo River between the boarder of Utah and Arizona, the lake is a popular vacation spot - with around 2 million people vising each year.

Scientists predicted that Lake Powell would be one of the first lakes in the western U.S. to get invasive mussels, so the National Park Service began a mussel monitoring program there in 2000. The FlowCAM is one of four early detection methods used by the NPS.

Learn more about the 2013 NPS Quagga Mussel Blitz here >>

Green Crab Larvae Threaten Maine's Clamming Industry

Work on assessing the damage green crabs have done to Maine's coastal and marine resources, began in the spring of 2014. Researchers are currently learning about different approaches for green crab control, and one of the instruments they are using is the FlowCAM dynamic imaging particle analysis system, which they’ve gained access to through a grant from Maine Technology Institute (MTI).

Read the full story on the FIT blog >>

Green Crab Larve Imaged by FlowCAM