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Chapter 11 Sea Turtles© NOAA Southwest Fisheries Science CenterIn the oceanic and neritic zones the principal impact isincidental capture by artisanal and commercial fisheries(reviewed by NMFS USFWS 2007b), primarily bypelagic longlines (Lewison et al. 2004; NMFS 2001).Localized declines in populations have coincided withincreased use of longline and gillnet fisheries (e.g., inMexico). Kaplan (2005) estimated a 5% annual mortalitydue to longline fisheries for the eastern Pacific populationwith an aggregate of 28% annual mortality due to coastalimpacts (e.g., egg/adult harvest and inshore fisheries bycatch).An estimated 50,000 individuals were taken bypelagic longline fisheries globally in 2000 (Lewison et al.2004). This level of take suggests pelagic longlines are oneof the more important human impacts. In United Stateswaters, the pelagic longline and shrimp trawl fisheries havebeen identified as the largest documented source of leatherbackmortality (NMFS 2001). Alternative methods andgear innovations (e.g., circle vs. J hooks; bait switching,TEDs) have reduced bycatch levels in recent years (NMFSUSFWS 2007b). Fixed fishing gear (e.g., gill nets, pot/trap buoy lines, pound nets) is problematic in coastal foraginggrounds (James et al. 2005) and in close proximityto nesting areas. Other documented impacts include vesselstrikes, ingestion of marine debris (e.g., plastics, hooks,nets, oil), and high contaminant levels (e.g., pesticides,heavy metals).Resource limitation in the eastern Pacific during cyclicalclimatic events (El Niño Southern Oscillation) hasbeen linked to decreased reproductive success and increasedvulnerability to anthropogenic mortality (NMFSUSFWS 2007b). This is not currently the case in thewestern Atlantic, however, anthropogenic climatic changesthat alter oceanic structure could influence prey availabilityand subsequent reproductive condition. Increasedtemperatures at nesting sites have been linked to changesin hatchling sex ratios on some beaches (NMFS USFWS2007b).Recent work with molecular markers suggests that thisspecies’ lower natal philopatry (tendency to return to theplace of an individual’s birth) and physiological ability toutilize higher latitudes and colder waters have enabled itto recolonize nesting and neritic foraging habitat (NMFSUSFWS 2007b). This characteristic may have importantramifications for recovery as detrimental human interactionsare reduced. The molecular marker studies alsorevealed low genetic diversity or division of populationsglobally, highlighting the need to exercise conservationmeasures based on larger population aggregates (e.g.,French Guiana, Suriname) that appear to be stable orincreasing (NMFS USFWS 2007b).ConservationRegulatory AuthorityAll life stages of all three turtle species are currently protectedon United States nesting beaches and in UnitedStates waters by the Endangered Species Act (ESA). Inthe United States, National Marine Fisheries Service(NMFS) and United States Fish and Wildlife Service(USFWS) jointly manage all three species; USFWS haslead jurisdiction on nesting beaches while NMFS has leadjurisdiction for marine waters.Current Conservation EffortsGlobal conservation efforts for all three species are principallycomprised of international conventions and treaties.The United States is one of 12 signatory nations on theonly international treaty dedicated solely to sea turtles:Inter-American Convention for the Protection and11-10Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report