Photo courtesy of George Fire Island, a team of scientific experts Proios was asked to identify the biological resources most likely to be impacted. The team also assessed what steps could be taken to better define and quantify these impacts from a management perspective. The experts’ initial findings were pre- In the sented and reviewed at a workshop for other scientists and federal, state, and local managers and agency representa- Breach tives. Final results appear in a NYSG publication, Impacts of Barrier Island Breaches on Selected Biological Re- Each year, millions of people flock to Long sources of Great South Bay, New York. Island’s popular south shore beaches. A Breach at Barrier islands, such as Fire Island, act as The hydrodynamic model developed by buffers that protect the mainland from Moriches Inlet Daniel Conley (formerly of MSRC) simu- storm surges and wave action. Separating lated the potential impacts that a new inlet This aerial view shows the mainland from its barriers is a system would have if it occurred either at Barrett the Moriches Inlet area of estuaries of great environmental, Beach or at Old Inlet on Fire Island. The during a 1980 breach ecological, and economic importance to modeled breaches had flow characteristics event. Moriches Inlet Long Island. (in foreground lined with comparable to the Little Pike’s Inlet breach a jetty) connects that formed in 1992 at Westhampton (see Moriches Bay (on the As has happened in the past when storms left) with the Atlantic have opened a breach through the island or Ocean (on right). formed a new inlet, people take notice. The Currents scouring the first concern is for safety and protection of shoreline along the bay weakened the barrier people and property. However, coastal which then breached planners, managers, decision-makers and during a storm. Rising the public are also greatly interested in the bay waters eventually impacts these changes can have on the broke through the bay’s natural resources. Studies indicate barrier and flowed into the ocean. that there is a strong probability that breaches or new inlets may occur in the The breach reached a future. These bays are home to many width of 2,900 feet in environmentally and economically impor- less than a year. It was tant plants and animals. People need to closed artificially soon thereafter. Moriches know how new breaches might affect the living resources found there. Inlet itself was created May 3, 1993: Above, an aerial view of Pike’s by a breach in 1931. Inlet shows a breach in the Westhampton As would be expected, Towards this end, New York Sea Grant barrier island on Long Island’s south shore. the breach allowed more worked with the Marine Sciences Research The top of the photo shows the fan-like pattern salt water into the bay, of sand deposition in the bay. which in turn had a Center at Stony Brook University to identify profound effect on the and assess the types of information bay’s living resources. required to properly evaluate the potential Predators entered the impacts of breaches on Great South Bay, bay, too, destroying the largest of Long Island’s south shore the oyster sets and undoubtedly impacting bays. Jay Tanski, NYSG’s coastal pro- the local economy. cesses specialist, Henry Bokuniewicz, professor of physical oceanography at MSRC and Cornelia Schlenk, Assistant Director of NYSG led the effort with support from the National Park Service. Using the results of a computer model that simulated what would happen if new inlets were created at two likely locations along

October 5, 1993: The breach at Pike’s Inlet was closed artificially. 10 Photos courtesy of NYSDEC photos). The model predicted that the new tautog and Atlantic herring (in winter).” Changes inlet would affect Great South Bay in two Conover adds that changes in the Bay’s Above, basic ways: by increasing the average salinity vegetation would change the habitat for Changes and reducing the amount of time water stays certain fish species. “Since recreational Below in the Bay (residence time). In essence, fishing tends to be concentrated in inlets, an almost certain effect of a new inlet will be to conditions in Great South Bay would become Team member Robert more like those found in Moriches and redistribute fishing effort in the Bay, perhaps Cerrato of MSRC Shinnecock Bays. drawing anglers away from Fire Island and evaluated how breaches Moriches Inlets.” on Great South Bay could To assess how affect shellfish and other Eelgrass is a common submerged vegetation benthic (bottom-dwelling) these physical invertebrates. Reports changes would in the Great South Bay. How much of it grows Cerrato, “Breaches affect the Bay’s and where is a question of light availability. remaining open a year or living community, According to aquatic plant expert Stuart less would probably have Elizabeth Cosper of Coastal Findlay of the Institute of Ecosystem Studies, minimal long-term “If a new breach caused the water clarity in impacts. However, and Environmental Studies Inc., longer lasting led off with what would happen to water Great South Bay to approach that of Moriches inlets could column productivity in the Bay. The plankton Bay, there would be an increase in the cause and nutrients in the water make up the maximum depth of eelgrass beds.” With substantial foundation of the Bay’s ecosystem. She clearer water, eelgrass is likely to expand its changes.” range at greater depth. Regarding intertidal, Species in reports “While increasing salinity might favor eastern Great smaller phytoplankton species, such as brown marsh vegetation Findlay reports, “The model South Bay would tide, the lower residence times and increased predicted relatively small changes in the probably shift more flushing would cause a decrease in nutri- average tidal range. However, even small toward those of the ents.” If a new inlet makes Great South Bay changes in water level elevations may affect western Bay. Populations intertidal vegetation if the new inlet persists of lady crab, razor clam, more similar to Moriches or Shinnecock Bay, and the bivalve Tellina Great South Bay should become a less for more than one or two years.” agilis would be altered as favorable environment for nuisance algal a result of a new inlet. blooms like brown tide. She predicted a The team of experts was in agreement that possible shift to larger algae that might comparative studies should be conducted A new breach would have between Great South Bay and the two neigh- both negative and positive decrease overall phytoplankton productivity in impacts on the hard clam, the Bay. The shift might adversely affect the boring bays, Moriches Bay and Shinnecock an economically important small animals in the water column but benefit Bay. The neighboring bays are reflective of the species of the Bay. shellfish on the bottom. Cosper also sug- higher salinities and greater oceanic mixing of Salinity and temperature gested that residence times might not waters that may be expected with a new inlet changes would slow the in Great South Bay. development of their necessarily be reduced evenly across the bay. fertilized eggs and larvae Thus, brown tides would tend to keep occur- so fewer clams would ring in areas with poor flushing. Says Tanski, “The information provided here survive. Their predators— should help in identifying the biota most likely channeled whelks and “The changes associated with a new inlet to be affected by new inlets and the general moon snails— would nature of the impacts. Just as importantly, it probably increase, indicated by the model would probably not reducing clam survival have major impacts on the finfish in Great provides guidance on the types of information even more. On the other South Bay,” says finfish expert David Conover and data needed to fill in our knowledge gaps hand, larger oceanic of MSRC. Many of the Bay’s existing fish and on measures that can be taken to obtain plankton species could populations are adapted to higher salinities, this information. In addition to providing improve food quality for managers with information they can use clams and more moderate so a predicted increase in salinity is not likely winter water tempera- to have a major influence on the overall immediately, it is hoped that suggestions and tures could decrease their species composition. “At most, we might recommendations presented in this report will over-winter mortality. expect a slight increase in the abundance of be of use in the development and design of marine species that are more commonly research, monitoring and other data gathering found on the continental shelf: dogfish and programs.” skates, northern kingfish, black sea bass, —Barbara Branca, Jay Tanski and material taken directly from Impacts of Barrier Island Breaches on Selected Biological Resources of Great South Bay, New York. See page 23 to order. 11