Collecting pycnogonids in Puget Sound (Washington, USA)

In the US Pacific Northwest, pycnogonids typically grow to maximum diameters of only a few centimeters. They feed on soft-bodied, sessile organisms, such as hydroids, anemones, and sponges. We collect pycnogonids on SCUBA (see video on right).  

It's hard to see and collect small pycnogonids, which usually are well camouflaged (Fig 1). We therefore collect hydroids and other potential foods, bring them back to the lab, and look for pycnogonids using a dissecting microscope (Fig 2).

Fig 1. Cryptic Pycnogonid covered with algae and other organisms

Fig 2. Pycnogonid clinging to hydroid under a microscope. Blue tick marks equal 1 millimeter