While its alien appearance and long, spiky tail may not draw many admirers, the horseshoe crab is a fascinating organism.

Horseshoe crabs are a vital part of the ecology of coastal communities along the Atlantic Coast. During the nesting season, their eggs become the principal food source for several migrating bird species including the federally-threatened Red Knot. In Maine, they have been observed to serve as mobile ‘apartment buildings’ for many species including bryozoans, the colonial "moss animals,” barnacles and even mussels.

A substance contained in the copper-based blood of the horseshoe crab is extremely important in the biomedical industry as an indicator of the presence of bacterial toxins. In addition, research on the compound eyes of the horseshoe crab has led to advances in our understanding of human vision.

Unfortunately, overharvesting and habitat loss pose a threat to horseshoe crabs in many areas along the Atlantic Coast. As part of the effort to understand this unique and important species, volunteers for the Damariscotta River Association (DRA) horseshoe crab monitoring program collect data on the quantity of horseshoe crabs at multiple sites in the upper Damariscotta River Estuary each spring.

DRA would like to recruit at least 15 volunteers who are able to donate at least an hour each week to the monitoring project between May 1 and June 15. Volunteers need not be DRA members, nor do they need to be available to monitor every day, as volunteers sign up for specific days depending on availability. The schedule is variable since monitoring times are tide-dependent.

Gladu is conducting a training session for interested volunteers on Saturday, April 29, from 3 to 5 p.m. The training will begin at the DRA headquarters on Belvedere Road for an overview of the process, then move to a field site to practice. Boots will be needed. Pre-registration is required.

For more information call 207-563-1393, email dra@damariscottariver.org, or visit www.damariscottariver.org.