If Fish are Healthy and Plentiful, So are Long Island Sound's Birds

Originally published in Connecticut Audubon Society's 2019 State of the Birds Report, Audubon Connecticut Executive Director Ana Paula Tavares offers her response to the essential question: "How can birds, fish, conservationists, and government adapt to a changing Long Island Sound?  Hint: Pass the Forage Fish Conservation Act.

Falkner Island sits unassumingly in central Long Island Sound.

From the Guilford shoreline, this crescent-moon-shaped land mass is a mere dot in a vast body of blue. A white lighthouse in the middle, the second oldest in the state, was  commissioned by President Thomas Jefferson in 1802. As you approach the 2.87-acre island in summer, the surrounding skies support a cloud of terns swooping, diving, and making their classic keeur or ki-rik calls.

The island is closed to the public, but a visit to the Falkner Island Tern webcam offers views of terns, American Oystercatchers, and, in the winter, harbor seals. To the Common and Roseate Terns of Connecticut, this recognized Important Bird Area is a crucial nesting ground with ideal access to a food source the terns rely on to survive and raise their young—forage fish.

Shad, river herring, and sand lance are examples of the small fish at the base of the aquatic food web known as forage fish. They are the main pathway for energy to flow from phyto- and zooplankton to higher level predators, including larger fish, seals, sharks, whales, and seabirds. Forage fish species that are anadromous (migrate up rivers to spawn) also connect marine and riverine ecosystems, serving as a food source for freshwater fish, egrets, kingfishers, and river otters. 

Fluctuations in forage fish populations can result in significant changes in marine communities and ecosystems, in turn affecting wildlife populations and local economies. In Long Island Sound, their populations can wax and wane in cycles depending on factors like water temperature, salinity levels, hypoxia, or disease. They are also susceptible to unregulated harvest, as when forage fish are caught in the nets of ocean-going fishing boats targeting other larger, regulated species. 

The terns of Falkner Island, among other common Long Island Sound-based birds such as Osprey, Northern Gannets, loons, gulls, and cormorants, depend on forage fish to survive and raise their young. Falkner Island supports over 95 percent (over 3,000 pairs) of the nesting Common Tern population in Connecticut, a state species of special concern. It also hosts a breeding population of Roseate Terns (about 50 pairs), a federally and state endangered species.

Along with Great Gull Island on the New York side of the Sound, these two nesting colonies make up 48 percent of the Atlantic Coast Roseate Tern population. Without an ample supply of small fish to eat nearby, birds will have to fly farther to find food, which results in longer periods of time between meals for chicks and, in the saddest cases, chick mortality. The delay and increased level of effort to find food ultimately reduces the nesting success of this already-endangered species. 

The scientific consensus is that shifting ocean temperatures and increasing acidification, both the result of climate change, will alter the distribution of fish species. Movement of forage fish to deeper or cooler waters outside the Sound equates to an uncertain future for our birds—terns especially.

With proper forage fish management that takes birds and other predators in the food chain into account—and research to better understand shifts in fish populations—we may be able to circumvent an irreversible food source loss for seabirds that depend on the Sound.

The annual success of seabird breeding-colonies is not always guaranteed. In the late 1800s, for example, terns were overcollected on their nesting grounds for use in the fashion industry and for market sales. Thankfully, the Endangered Species Act and the Migratory Bird Treaty Act, as well as other conservation efforts, have resulted in population recoveries in the Northeast.

Protected nesting areas are essential. Thanks to stewardship by the United States Fish and Wildlife Service, Falkner Island is a safe nesting area for terns. Great Gull has been managed effectively for decades by the American Museum of Natural History’s Great Gull Island Project. But protected nesting areas are not enough by themselves.

We must take additional steps to help protect our birds from the effects of a shifting marine ecosystem. When regional fishery councils are making management decisions, they need to consider best practices for maintaining forage fish population abundance, diversity, and distribution. But before making such decisions, fisheries managers also need to know how they will affect existing fisheries and fishing communities. Then they need to develop management plans that will ensure enough forage fish to support both a fishery and that species’ ecosystem.

We know it works. A comprehensive management plan has contributed to the renewed health of the menhaden population, which in turn has helped spur the recent boom of the Osprey population around the Sound and along the East Coast.

By putting similar fishery management plans in place for forage fish species, we may be able to help safeguard other birds that depend on the Sound’s vibrant ecosystems. State, federal, and interstate management agencies such as the Atlantic States Marine Fisheries Commission and the New England Fisheries Management Council have the opportunity to ensure that forage fish—and the terns that rely on them—have a fighting chance.

The changing climate is the number one risk to birds and people today. Both on land and in the Sound, species are shifting and relationships between predators and prey that have developed over thousands of years are strained. If we ignore these risks— ocean acidification and warming water temperatures among them—we threaten forage fish and therefore the health of seabird and other aquatic creatures.

There are economic costs as well: Forage fish are an important commodity for both commercial and recreational fisheries, which in Connecticut generated $817 million in sales and supported 6,280 jobs in 2016. Fishery management and switching to renewable energy sources are just a few of the measures we can take to protect the region’s natural resources into the future. Long Island Sound is a complex and interconnected ecosystem, from its birds and seals down to its small forage fish.

We face a vital task in protecting the Sound’s organisms, and the birds that we care so much about can serve as a starting point. Falkner Island may be home to the second oldest lighthouse in the state, but without its terns, it is an empty nest.

How you can help, right now