Between July 2009 and September 2011, we conducted the first monitoring and research project on coastal river otters (Lontra canadensis) inhabiting Martha’s Vineyard (MV). With sponsorship from Sheriff’s Meadow Foundation, a grant from the Edey Foundation, and private donor funding, we surveyed ponds, wetlands, and shoreline for otter tracks, scat, and trails to gather baseline data on the distribution of this top predator in our watersheds.
We are grateful to many private landowners as well as to The Martha’s Vineyard Land Bank, Mass Audubon at Felix Neck, The Nature Conservancy, Sheriff’s Meadow Foundation, The Trustees of Reservations, Vineyard Conservation Society, and Vineyard Open Land Foundation for opening their properties for otter mapping and monitoring.
Our wildlife cameras sometimes capture beautiful photos of otters such as this one!
Coastal River Otter at Edgartown Great Pond
Monitoring and Mapping
We monitored sites once per month to document the amount of otter activity (scat, tracks, scent mounds) at each site and to collect scat for diet analysis. We mapped 150 sites with otter activity on the Island, and visited those sites once per month to document the amount of otter scat and activity at each site. Based on activity patterns, we selected 20 latrine sites as baseline sites for future monitoring. Between October 2010 and December 2012, Liz Baldwin monitored these sites to study Vineyard coastal river activity patterns using motion sensing wildlife cameras for her RiverOtterActivityPatterns M.S. Thesis. Mapping of overland trails is ongoing each winter, when the leaves are off the trees and shrubs. For coastal otter biology/behavior information, click here.
Otter latrine site on Edgartown Great Pond
Edgartown Great Pond otter with pups
– photo by Anne Mazar
Otter Diet Analysis
We collected over 300 otter scat samples and used a sub-set of these to create a guide to otter diet analysis for the region that was distributed to several Island science teachers. Identification of prey in the remaining samples will be complete in fall of 2012. Otters in southeastern Massachusetts eat a variety of fish and crustaceans. Most surprising to us, was the relative abundance of small fish species in otter scat. Some of these species include Mummichog and Golden Shiner:
Mummichog
Golden Shiner scale
Otter with Mummichog
– photo by Jeff Bernier