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Chapter 11 Sea Turtles1992). Calculating sightings per unit effort (SPUE)allowed for comparing data spatially and temporallywithin a study area (Shoop and Kenney 1992). SPUE iscalculated as:SPUE = 1000*(number of animals sighted)/effortData obtained from the Navy included point shapefilesof valid sightings for all turtle species and pre-calculatedeffort grids for each season. The original sightings datawere taken from National Marine Fisheries Service andNortheast Fisheries Science Center (NMFS-NEFSC)aerial surveys, NMFS-NEFSC shipboard surveys, and theNorth Atlantic Right Whale Consortium database. Thedata were carefully screened and verified by Navy contractorsbefore inclusion in the model. Invalid records werenot included in the analysis. The data set constitution(multiple efforts, geographic scope over several decades)precludes the ability to assess trends. Sightings were spatiallyand temporally oriented towards marine mammalswith opportunistic recording of sea turtles. Using theformula above, SPUE was calculated for each species, foreach season, and for each ten minute square.Nesting data, compiled from state sources, were mappedand incorporated into the analysis to identify importantcoastal areas. For Virginia and North Carolina, nestinglocations were obtained from state experts. For theother states in the region, the National Oceanic andAtmospheric Administration (NOAA) EnvironmentalSensitivity Index (ESI) data were used to represent thenesting and distribution areas.Maps, Analysis, and Areas of ImportanceLeatherback TurtleThe assessment results suggest that the distribution ofleatherbacks within the region varies by season (Figure11-1). Observations (n = 187; years = 1979 to 2003) wereprimarily in the summer months. The sightings duringthe spring and fall were limited and widely distributed.No observations were available during the winter months.Observations during the summer months were concentratedalong the inner Continental Shelf and adjoiningcoastal areas from Maryland to southern Long Island,New York. In addition, a relatively large number of sightingswere concentrated along the shelf break off Virginiato the northern portions of the region. The leatherbackhad a more northern distribution than the loggerheadturtle, with multiple sightings in the Gulf of Maine, theSouthern New England shelf, and off the coast of NovaScotia. Documented nesting initiated during the monthsof April, May, and June occurred in North Carolina(n=4). According to the ESI data, areas of concentrationwere more northern in extent than the other two species:northern New Jersey, Connecticut, and Rhode IslandCoasts.The seasonality of the sightings, with the majority of thesightings in the summer, follow the general pattern ofincreased turtle sightings as waters warm in the summermonths (Braun-McNeil and Epperly 2002). The relativelyhigh concentrations of sightings in the south central portionof inner shelf and coastal areas suggests that thoseareas are potentially of greater importance for the leatherback.The data set precludes an assessment by life stage(adult, juvenile) as well as use of larger coastal estuariessuch as Chesapeake Bay, Delaware Bay, and Long IslandSound.Green Sea TurtleGreen sea turtle observations in the region included in thedataset were limited to five sightings during the summerand fall months in the south central portions of the shelf(Figure 11-2). A limited number of nests initiated duringthe months of June, July, and August were documentedin northern North Carolina (n=15) and the ocean coastof Virginia (n=1). Areas of concentration, as per the ESIdata, were more widespread than the loggerhead turtles:around Long Island, the Maryland and Virginia Shore,and the majority of the Chesapeake Bay. Because of thelimited amount of data currently available for this species,interpretations of potentially important areas in theregion are unwarranted.Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report 11-