Thursday, March 29, 2007

My reseach

Just wanted give a little background information on my proposed research

Estuaries in Long Island, New York, have been documented as some of the most productive in terms of both primary production and shellfish harvest (COSMA 1985). Bay scallops, Argopecten irradians, once supported a vibrant fishery that contributed to high productivity in Long Island waters. Scallop populations crashed in 1985 after the occurrence of the first brown tide, Aureococcus anophagefferens, in the Peconic Bays, and subsequent blooms pushed scallops to the brink of extinction (Tettelbach and Wenczel 1993). Reseeding efforts commenced after the blooms with relatively little success (Tettelbach and Wenczel 1993). One potential reason for the lack of recovery was the low densities of spawning adults, as numbers of adult scallops in the Peconics has rarely been over 0.5 animals/m2 over the last 10 years (Lewis and Rivara 1998). Competition and intense predation may be contributing recovery failure, but I hypothesize that the major contributing factor is loss of habitat. Low survival leads to low densities of adults, and scallop survival has been most often linked with predation (Tettelbach 1986; Prescott 1990; Tettelbach, Smith et al. 1997). Also, predation rates are much lower in vegetated habitats when compared to bare sand (Prescott 1990; Tettelbach, Smith et al. 1997). Locally, bay scallops preferred habitat is eelgrass, Zostera marina, an association that has long been recognized (Belding 1910; Gustell 1930),and examined in multiple studies (Pohle, Bricelj et al. 1991; Garcia-Esquivel and Bricelj 1993). The same brown tide blooms that caused the scallop population to crash also shaded out eelgrass (Dennison 1987). High nutrient loads from increasing development of the East End of Long Island can also lead to eutrophication, which has devastating impacts on eelgrass (Dennison, Orth et al. 1993) and leads to dense macroalgal blooms (Valiela, Foreman et al. 1992). Fishing gear directly removes eelgrass biomass (Boese 2002). The aforementioned factors have led to current Zostera beds in eastern Long Island to exist as a mosaic of patches that vary in shape, size, and degree of isolation from other patches. Habitat patch size can significantly affect recruitment (Bologna and Heck 2000) and survival (Irlandi, Ambrose et al. 1995) of marine bivalves. Furthermore, a regime shift from an eelgrass dominated system to a macroalgal dominated system can potentially be detrimental to bay scallops (Valiela et al 1992). The relative value of different juvenile scallop habitats has received little attention, and few studies have examined the role that changing eelgrass patch architecture (ie, size, shape) has in scallop recruitment, growth and survival. Understanding how changes in Peconic basin habitats may affect bay scallops is paramount for their successful restoration and recovery efforts.

I plan to build artificial seagrass units (ASU) of two different shapes and sizes, replicated in triplicate, using Vexar mesh and polypropylene ribbon. I am using ASUs to correct for confounding variables like shoot density, canopy height, etc. ASUs have been used in previous studies (Bologna and Heck 2000). I will be able to test recruitment, growth and survival of scallops within these patches. Also, in field experiments I will test survival in different habitat types, eelgrass, codium, mixed macroalgal communities, crepidula, and bare sand. Eventually I also plan to conduct a diver benthic survey throughout the Peconics for submerged aquatic vegetation using the Braun-Blanquet method to determine whether or not there are suitable habitats for restoration, and present the results to Suffolk County, Easthampton Township and Southold Township.

Belding, D. (1910). A report upon the scallop fishery of Massachusettes. Boston, The Commonwealth of Massachusettes.

Boese, B. (2002). "Effects of recreational clam harvesting on eelgrass (Zostera marina) and associated infaunal invertebrates: in situ manipulative experiments." Aquatic Botany 73: 63-74.

Bologna, P. and K. Heck (2000). "Impacts of seagrass habitat architecture on bivalve settlement." Estuaries 23: 449-457.

COSMA (1985). Suffolk County's hard clam industry: an overview and an analysis of management alternatives, MSRC SUNY Stony Brook.

Dennison, W. (1987). "Brown tide" algal blooms shade out eelgrass. National Shellfish Association, Halifax, Nova Scotia.

Dennison, W., R. Orth, et al. (1993). "Assessing water quality with submerged aquatic vegetation-Habitat requirements as barometers of Chesapeake Bay health." Bioscience 43: 86-94.

Garcia-Esquivel, Z. and V. Bricelj (1993). "Ontogenetic changes in microhabitat distribution of juvenile bay scallops, Argopecten irradians irradians (L.), in eelgrass beds, and their potential significance to early recruitment." Biological Bulletin 185: 42-55.

Gustell, J. (1930). "Natural history of the bay scallop." US Bureau of Fisheries Bulletin 46: 569-632.

Irlandi, E., W. Ambrose, et al. (1995). "Landscape ecology and the marine environment: how spatial conifguration of seagrass habitat influences growth and survival of the bay scallop." Oikos 72: 307-313.

Lewis, D. and G. Rivara (1998). An assessment of shellfish resources in the tributatires and embayments of the Peconic Estuary, Cornell Cooperative Extension. Peconic Estuary Program.

Pohle, D., V. Bricelj, et al. (1991). "The eelgrass canopy: an above-bottom refuge from benthic predators for juveinle bay scallops Argopecten irradians." Marine Ecology Progress Series 74: 47-59.

Prescott, R. (1990). "Sources of predatory mortality in the bay scallop Argopecten irradians (Lamark): Interactions with seagrass and epibiotic coverage." Journal of Experimental Marine Biology and Ecology 144: 63-83.

Tettelbach, S. (1986). Dynamics of crustacean predation on the northern bay scallop, Argopecten irradians, University of Connecticut.

Tettelbach, S., C. Smith, et al. (1997). "Bay scallop stock restoration efforts in Long Island, New York: approaches and recommendations." Journal of Shellfish Research 16: 276.

Tettelbach, S. and P. Wenczel (1993). "Reseeding efforts and the status of the bay scallop Argopecten irradians (Lamark 1819) populations in New York following the occurence of "brown tide" algal blooms." Journal of Shellfish Research 18: 423-431.

Valiela, I., K. Foreman, et al. (1992). "Couplings of watersheds and coastal waters: Sources and consequences of nutirent enrichment in Waquoit Bay, Massachusettes." Estuaries 15(4): 443-457.

Shellfisherman to search new spot for oysters, clams

Some local Long Island issues, courtest the Greenwich Time

Staff Writer

Published March 27 2007

After more than 200 years of sifting Long Island Sound's sandy floor from canoes, skipjacks, steam engines and trawlers, shellfishermen say they've figured out which areas yield the meatiest, most abundant oyster and clam crops.

The prized underwater beds are privately owned or leased from the state Department of Agriculture, and are sold from generation to generation of shellfisherman.

So its rare for a shellfisherman to do what Greenwich's Jardar Nygaard is proposing--seek to farm unclaimed and unproven acreage.

"There's a risk. There is absolutely a risk involved, but you're making an informed decision when you do this," said Nygaard, owner of Fjord Fisheries seafood shop in Cos Cob. "You're going to be right to some extent and you really just risk what you feel it's worth."

Nygaard is seeking to lease two plots in the Sound, totaling about 183 acres and located a few thousand feet southeast of Greenwich Point. To farm the plots, Nygaard checked with the agriculture department's Milford-based Aquaculture Bureau to make sure the sites are available. The bureau then advertised Nygaard's intentions and called for bids to lease the property.

Bids must be at least $4 per acre per year and are due Monday. If he wins the leases, Nygaard said, he intends to start farming the plots right away, with a goal of selling clams.

What he's doing is highly unusual in the world of shellfishing, said David Carey, the bureau's director.

"The leases are automatically renewed at the choice of the lessee, if he meets the terms and conditions. That's why we only get about 10 new applications a year," Carey said."You'd think that shellfishermen, between (the year) 1800 and last year, have pretty much picked out the best areas."

But the Sound has a way of surprising shellfishermen who think they've mastered the practice, said Ed Stilwagen, who works about 3,000 acres in the Sound as owner of Byram River-based Atlantic Clam Farms.

"If you're around a while you find out where the good spots are, but it changes based on the current and other conditions. It's not a totally consistent thing at all," Stilwagen said. "There's a lot of luck involved. Sometimes it's better to be in some areas than others, for reasons we don't even know about."

Even so, state officials give potential shellfishermen some time to survey the shellfishing beds they intend to lease. Under a one-day permit issued by the state Department of Environmental Protection, Ny gaard spent several hours on his hydraulic dredge last week, surveying about four of the acres he's interested in.

Nygaard, who already leases 50 acres in Greenwich and 220 in Westport, believes that eddying at high and low tides could help seeds take hold in the beds and yield shellfish in the proposed sites.

"Also, during storms, it could create large amounts of shell deposit, which is also a good environment," Nygaard said.

Still, the proposed beds --–one of which lies entirely in Greenwich, while the other straddles the Greenwich-Stamford line --–could be difficult to manage, Nygaard said. Depths vary widely from place to place and waters can be choppy most days, which makes it difficult to do the sensitive work of trawling the bottom of the Sound for clams, Nygaard said.

For Leslie Miklovich, co-owner of Hillard Bloom Shellfish in Norwalk, the only true gauge for how fertile an area is for shellfishing is history itself.

"Historically we know which grounds are the best," said Miklovich, whose business farms about 10,000 acres in the Sound and whose family has been in shellfishing since 1875. "Just history from the old-timers, that's what it's about. Over the years, everything has been tried. All these grounds have been tried before."

For Nygaard, who has long been interested in aquaculture and whose family went into salmon farming years ago, trying to find a good shellfishing crop where no one has before may offer its own rewards.

"I just think that cultivation of shellfish is a good business to be in," Nygaard said. "For one thing, it's sustainable, and basically eco-friendly."