Chatham is more than sharks when it comes to science. At Wellfleet Bay Mass Audubon’s 22nd annual Cape Cod Natural History Conference at Cape Cod Community College last weekend, a number of projects relevant to the area were discussed.
Mark Borelli of the Center for Coastal Studies discussed the use of cutting edge mapping from two small craft with shallow drafts, each equipped with two methods of using sonar, bathymetry and side-scan radar, in discovering the geologic changes in the substrate of the Outer Cape.
“Bathymetry is like emptying water out of the ocean and seeing the bottom," Borelli said. Side-scan radar visualizes elevations, creating a virtual trip through the peaks and canyons of an area, even very shallow ones like Pleasant Bay, one of three places surveyed.
Data from Pleasant Bay shows eelgrass diminished from 100 acres to 15 over the course of a few years. Mapping showed “it was natural processes” which choked off eelgrass “even as they also open up the bay for new growth,” Borelli said.
Thirty-nine macro-invertebrates showed up in 33 bottom samples of Pleasant Bay. The team also tested water quality, sediment size and salinity. Chatham fisherman Captain Ted Lucas piloted boats for these excursions whose data create a “baseline snapshot” to compare to future mapping by the same techniques, Borelli said.
Another partnership between scientist and fishermen, involving Harwich lobsterman Mark Leach, was Kara Dodge’s tagging of captured endangered leatherback turtles in Nantucket Sound. The tags' camcorders let researchers see from the turtle’s point of view. Transponders allowed Remus AUV’s (developed by the Woods Hole Oceanographic Institution to spy on great white sharks) to follow the leatherbacks. Data gathered showed that the huge turtles travel most often in ferry lanes, eat jellyfish (sometimes up to 123 in two hours), swim on the surface, dive a large percent of the time, and linger above the sea bottom. Data might improve human-turtle interactions and help prevent entanglement in fishing gear.
Bradford Bower of the Massachusetts Coastal Waterbird Program sampled invertebrates at three Cape beaches including Chatham's Forest Beach. The idea was to begin to quantify what endangered piping plovers eat and how dredging, beach raking, over-sand vehicles and beach nourishment could affect plover numbers, especially the juveniles that feed in the wrack line while adults forage the beach.
Though numbers of the Atlantic plover population have risen since 1986 to about 2,000 to 3,000, according to Coastal Waterbird Coordinator Cris Luttazi, productivity of chicks is declining slightly. She stressed that every egg-laying adult was important, citing one, Beulah, who successfully fledged 11 chicks in five years. Scientists tracked Beulah via her bands which reveal so much information about individual birds and their behaviors and status that the program has restored bird banding, with programs for schools and the public alike.
Wild Care officials spoke of receiving seabirds (storm-wounded, tangled in monofilament, from the Outer Cape including Chatham) which were placed in state-of-the-art warming pools to revive them.
Along with 13 onstage presenters, 10 presenters with posters in the lobby explained their work. Master’s degree candidate Katherine Johnson’s research shows genetic differences in horseshoe crab populations on the north and south side of the Cape. If population levels remain low, differentiation may increase. Localized isolated populations adapted to a specific area may be more vulnerable to depletion, Johnson said.
“Chatham is a big spot for harvesting horseshoe crabs. We have to tread carefully and watch the numbers, That’s best for the crab and best for the fishing industry,” she said. Regulations should be tailored to consider genetically distinct populations, she suggested.
Other posters looked at seals. Northwest Atlantic Seal Research Consortium’s Chris Reeves said the question is not how many seals there are but what are they doing.
“Fishermen blame seals for taking fish but we don’t really know. Large populations may benefit the ecosystem by contributing poop which nourishes plankton,” Reeves said. A coalition of scientists and fishermen, coordinated by WHOI’s Andrea Bogomolni, aim to find the seals’ true “ecological role,” while the Center for Coastal Studies' Lisa Sette is charted 2014 arrival and departure times, numbers and distribution patterns of both harbor and gray seals from haul-outs to breeding sites. ("The maximum area-wide gray seal count was 21,117," on May 13. Eighty percent are on South Monomoy.)
A.P. Nauset High school students’ poster detailed a study of Wellfleet oysters. Senior Sonja Berquist of Harwich said students found that “ph and salinity levels could affect oyster growth in both positive and negative ways.”
Also of interest were marine biologist Rodney Rountree’s groundbreaking discoveries of calls specific to individual freshwater fish species. Fish cricket, cough, tick, drum, using their air bladders, or rubbing fins, bones or teeth together for communication about mating, defense and turf. Dr. Erik Zettler said plastic debris in oceans aren’t floating rafts of discarded implements and bottles, but bits and pieces on which diatoms gather producing mouth-watering scent for feeding creatures to send up through the ocean food web. And results of intensive collaborative collection of 15,000 specimens of pollinators from Dukes county initiated by National Museum of Natural History's Paul Goldstein showed, in spite of some individual species declines, high diversity in pollinators with which the introduced honeybee may compete to the natives’ detriment.