Restoration of Diadromous Fish Populations in Tributaries of Waquoit Bay, Cape Cod, Massachusetts
Stephen T. Hurley
Abstract.—Waquoit Bay is a coastal estuary located on the south side of Cape Cod. The primary rivers feeding the bay, the Quashnet and Childs rivers, are small, coldwater, groundwater-fed streams. Most of the watersheds of both rivers were originally set aside in the 1600s as a plantation for the Native American Mashpee Wampanoag tribe. The rivers were heavily modified in the late 1700s by the building of mill dams and later in the 1800s by cranberry agriculture. The anadromous Brook Trout Salvelinus fontinalis fisheries in both rivers were acclaimed in the early 1800s. Anadromous river herring Alosa spp. runs were created on both streams by connecting the streams to Johns Pond, a natural kettle hole pond. After anadromous Brook Trout populations declined due primarily to habitat loss, efforts were initiated in the 1950s to restore anadromy to Brook Trout in Cape Cod rivers by overstocking with hatchery Brook Trout. After this project, land protection along the river started with the purchase of abandoned cranberry bogs. Both rivers were heavily stocked with Brown Trout Salmo trutta in the 1970s and 1980s to create a sea-run Brown Trout fishery. In 1976, Trout Unlimited began an ongoing habitat improvement project in the Quashnet River. In the 1970s and 1980s, the rapid development of Cape Cod threatened the watershed. In 1988, the Waquoit Bay National Estuarine Research Reserve was formed and the Commonwealth of Massachusetts purchased land in the watershed to preserve it as open space. As part of the purchase agreement, a potential well site was reserved, which led to studies by the U.S. Geological Survey on the hydrology of the Quashnet River and the impact of potential wells. In the early 1990s, fisheries management shifted away from the stocking of Brown Trout to focus on the native Brook Trout fishery. The Mashpee National Wildlife Refuge, a consortium of landowners centered on Waquoit Bay, was formed in 1995. In 1997, the contaminant ethylene dibromide from the former Otis Air Force Base Superfund site was found to be entering the upper Quashnet River. This led to the creation of a system of berms and groundwater extraction systems. The failure of part of the berm system led to concerns about fisheries impacts, and a restoration plan was developed. A Brook Trout passive integrated transponder tagging project was initiated on the Quashnet River in 2007, and the Brook Trout population has been annually sampled since 2000. In 2008–2010, adult wild Brook Trout from the Quashnet River were transplanted to the Childs River and a wild Brook Trout population was reestablished. Nitrogen loading from the watershed has become a major issue for the Waquoit Bay estuary, causing algae blooms and water-quality impacts. The fisheries of the Waquoit Bay tributaries have been protected and enhanced by an ongoing combination of land protection, fisheries management and research activities, and habitat improvements involving a wide variety of partners. Watershed development and potential climate change continue to threaten both the estuarine resources of Waquoit Bay and the native freshwater and diadromous fisheries of its tributaries.