By Victoria O’Neil and Mark A. Tedesco
The winter of 2014 has been a cold and snowy season, but spring is almost upon us. Soon the temperatures will begin to rise, and the northeastern United States will awaken: the snow will melt away, the ground will begin to thaw, and the early spring blooming plants such as Forsythia and Amelanchier will emerge from hibernation to produce their showy blooms. As much a signpost of spring is the annual migration of the alewife (Alosa pseudoharengus) to local rivers and creeks.
The alewife is a member of the herring family whose species range from the Canadian Maritimes to the Carolinas. Alewives, also known as river herring, are anadromous fish that, like salmon, spend the majority of their lives out at sea and only enter freshwater systems to spawn. A relatively diminutive fish (adults average 12 inches in length), these silvery, iridescent creatures are built for speed, with a sleek and slender frame allowing them to move quickly through the water.
Over the next few weeks, from mid-March through May, thousands of these tiny fish will begin their journey from the open ocean to our Long Island Sound estuaries, rivers, and creeks. Their journey from ocean to estuary to freshwater river will take several weeks and they will cover hundreds of miles. Along the way, they will serve as an important high energy food source for tuna, whales, cod, dolphins, harbor seals, ospreys, eagles, river otters, herons, raccoons, and egrets. Upon reaching the same rivers and creeks from which they hatched, the alewife adults will spawn millions of golden-green eggs. While the adults leave the rivers soon after spawning to return to the ocean, the eggs will hatch into juveniles that will stay and grow in the freshwater systems throughout the spring and summer. As the temperatures begin to cool in the early fall, the young alewives too will leave and migrate to the open ocean. In three to five years, this cohort will mature and return to their natal river to spawn.
Over the last hundred years, alewife populations have decreased throughout their range, including New York. Spawning runs in Long Island Sound tributaries have been lost or severely diminished due to overfishing, habitat degradation, poor water quality, and, most importantly, the installation of impassable structures, such as dams, weirs, and culverts, that prevent fish from reaching their spawning grounds.
Alewife runs were probably once a common phenomenon along the north shore of Long Island. Without a comprehensive survey in recent decades the current extent of the spawning run on Long Island is uncertain. The Long Island Sound Volunteer Alewife Survey aims to fill this knowledge gap by providing biologists, managers, and researchers with basic information on the alewife runs. The survey helps determine if and where a run exists, the timing and length of the run, and how many fish are making the run.
The Volunteer Alewife Survey effort on Long Island began in 2006 through the Environmental Defense Fund and the South Shore Estuary Reserve. The effort was initiated to support a major multi-stakeholder effort to restore diadromous fish (i.e., fish that spend their lives in fresh and saltwater) to Long Island’s south shore. Today, the effort is headed up by Seatuck Environmental Association and NYS Department of Environmental Conservation, and monitoring has expanded to sites in the Peconic estuary and Long Island Sound. Data collected by citizen scientists in this program has assisted with the installation of fish passage projects around the island.
To become an alewife citizen scientist, volunteers with no prior alewife monitoring experience, attend a one-hour training session to learn about alewife life cycle, ecological importance, identification, and survey protocol. At the session, volunteers can choose or be assigned to a creek to monitor near their home. These citizen scientists are then encouraged to make observations from set vantage points downstream of the first significant impediment to migration along the waterbody. From mid-March through late-May, volunteers will visit their designated waterbody at least once a week for a minimum of 15 minutes at a time. During their visit, they will record the date, weather conditions, water temperature, if fish are present or not, an estimate of how many fish are present, duration of their visit, and any notable evidence of alewives (i.e., scales or carcasses left on the creek bank by a predator). Citizen scientists are encouraged to bring a camera or phone with them to take photos and videos of any alewife they may see. All of this information is then uploaded to an online database that is later accessed by biologists and researchers. For more information visit: http://seatuck.org/index.php/feature-1/174-2014-alewife-survey
About the Authors: Victoria O’Neil is the New York Habitat Restoration Coordinator for the Long Island Sound Study. She works for the New England Interstate Water Pollution Control Commission and is housed in the New York State Department of Environmental Conservation’s Bureau of Habitat Protection in East Setauket, NY.
Mark Tedesco is director of the U.S. Environmental Protection Agency’s Long Island Sound Office. The office coordinates the Long Island Sound Study, administered by the EPA as part of the National Estuary Program under the Clean Water Act. Mr. Tedesco is responsible for supporting implementation of a Comprehensive Conservation and Management Plan for Long Island Sound, approved in 1994 by the Governors of New York and Connecticut and the EPA Administrator, in cooperation with federal, state, and local government, private organizations, and the public. Mr. Tedesco has worked for the EPA for 25 years. He received his M.S. in marine environmental science in 1986 and a B.S in biology in 1982 from Stony Brook University.