Editorial Introduction Refocusing on Leatherbacks: Conservation Challenges and Signs of Success

The leatherback sea turtle (Dermochelys coriacea)has been called Mercury’s turtle since the Middle Ages(Rondelet 1554), because its teardrop body plan and ridgesresemble the shape and strings of Mercury’s instrument,the lyre (leut, luc, or luth in French, lau´d in Spanish). And,because Mercury was the winged Roman messenger god,leatherbacks should perhaps be considered winged mes-sengers themselves. Certainly, their graceful underwaterﬂight, as illustrated on our cover, makes them appearwinged as they glide through their blue watery oceanicrealm, but they are also messengers—the harbingers ofpelagic environmental change and threats occurring withintheir habitat. We would do well to heed their silentmessage, and this journal issue addresses many of theconcerns relating to their survival.Over a decade has passed since Chelonian Conser-vation and Biology published the initial special focus issueon the leatherback turtle (Vol. 2, No. 2, October 1996). This was the inaugural contribution in a series of 5 specialissues or sections that have focused on hawksbills, Kemp’sridleys, Blanding’s turtles, and gopherine tortoises. As theﬁrst journal to dedicate its pages exclusively to leather-backs, that issue contained 18 contributions that focusedon the biology and conservation of leatherbacks around theworld. Those papers provided a broad perspective for aspecies that was fast becoming the symbol for theimperiled state of sea turtles. Collectively, the journaladdressed many issues, but 2 papers that sounded thealarm on regional extinctions captured much of theattention. Chan and Liew (1996) chronicled the disap-pearance of leatherbacks at the once-remarkable Tereng-ganu rookery in Malaysia, and Spotila et al. (1996)presented the grim potential of extinction for the entirePaciﬁc Ocean. In addition to these sobering accounts,encouraging papers were presented on skeletochronology(Zug and Parham 1996) and chondro-osseous development(Rhodin et al. 1996, building on previous work by Rhodin1985) that demonstrated rapid growth and relatively earlymaturation by leatherbacks. Thus, despite the real threat ofextinction in the Paciﬁc, data also suggested thatleatherbacks, because of their relatively shorter generationtimes, could potentially respond to conservation effortsmore quickly than many of the hard-shelled cheloniid seaturtles.Since the ﬁrst special focus issue, the leatherback’sstatus in the IUCN Red List has been upgraded fromendangered to critically endangered because of a globaldecline in nesting frequency (Sarti-Marti´nez 2000). Yet, ascaptured in the pages of the ﬁrst special focus issue, therewere largely different nesting trends in the Atlantic andPaciﬁc. Whereas most, if not all, known Paciﬁc nestingpopulations had experienced precipitous declines duringthe previous decades (Chan and Liew 1996, Spotila et al.1996), many rookeries in or near the Atlantic had beenstable or increasing (e.g., Boulon et al. 1996; Girondot andFretey 1996; Hughes 1996). Since then, it has becomeapparent that this trend continues (Spotila et al. 2000;Reina et al. 2002; Eckert and Kerr Bjorkland 2004; Duttonet al. 2005), and, based on the 2006 state of the world’sturtles report (Mast et al. 2006), annual leatherback nestingnumbers are substantially greater in the Atlantic than in thePaciﬁc. The burning question is: why are the 2 ocean basinpopulations behaving so differently? Perhaps this disparityresults from marked differences in ﬁsheries by-catchmortality and/or harvest rates between the 2 ocean basins.We know that marine ﬁsheries have had major impacts onleatherbacks (Eckert and Sarti 1997; Lewison et al. 2004;James et al. 2005; Carranza et al. 2006), but it is debatablewhether by-catch rates are sufﬁciently different to result inthe observed regional trends. Egg and female harvest mayalso contribute to differences; like ﬁsheries, these areubiquitous threats (Sarti 2000; Kaplan 2005), but again,are they so different in the Atlantic vs. the Paciﬁc? Othershave suggested that the responsible factors may be lowerreproductive output and hatching success and longer adultfemale remigration intervals in the Paciﬁc vs. the Atlantic(Bell et al. 2003; Wallace et al. 2006; Saba et al. 2007). Indeed, the ocean basin dichotomy has been the focus of atleast 2 sea turtle expert working groups (NOAA TurtleExpert Working Group; Paciﬁc-Atlantic Sea TurtleAssessment Workshop-PASTA, Lutcavage et al. 2006). The reality, however, is that we still do not have a smokinggun fully explaining the regional patterns, and it is clear