Lessons from recent telemetric studies: Oceanic movements of leatherback turtles & interaction with open-water fisheries Graeme Hays, Jonathan Houghton & Andrew Myers University of Wales Swansea

Interaction with pelagic long-line fisheries Overlap with pelagic fisheries ~ 50,000 leatherbacks taken p.a. Lewison et al (2004) Ecology Letters 7: 221-231 - Foul hooking - Effect evident at population level

Pacific leatherback turtles face extinction Nature / Vol. 45 / 1 June 2000 / 529-530 brief communications Pacific leatherback turtles face extinction Fisheries can help avert the alarming decline in population of these ancient reptiles 1600 1200 # leatherbacks nesting 800 400 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 Year (July to June) Spotila et al (2000)

Pacific decline - distinct migratory corridors Lewison et al (2004)

The Atlantic question Serious concerns following Pacific decline Existence of migratory corridors? Prompted US government action

Closure of fisheries to US long-line fleet Exclusion from prime sites in Pacific & Atlantic (e.g NED) Contentious decision 55%  in by-catch required Two areas to be addressed: Identify areas of interaction Develop new fishing methods NED USA

Identifying areas of interaction – horizontal movements NED Hays, Houghton & Myers (2004) Pan-Atlantic leatherback turtle movements Nature 429: 522 Ferraroli, Georges, Gaspar & Le Maho (2004) Where leatherback turtles meet fisheries Nature 429: 521-522

Horizontal movements – importance of frontal features? Ferraroli et al (2004) Nature 429: 521-522

Vertical movements - contribution of new technology Satellite Relay Data Loggers (SRDLs) - Horizontal & vertical (diving) movements - ‘Open-ocean’ behavioural studies: Hays et al (2004) Nature 429:522 Hays et al (2004) Anim. behav. 67:733-743

50 Mean depth of dives during 6 hour periods (N=3,304) (N=9 turtles) 50 Mean depth of dives during 6 hour periods (N=3,304) (N=9 turtles) 100 mean depth (m) 150 200 250 M J J A S O N D J F M A M J J A S O N D J 2002 2003 8000 N=16,767 Max=1230m >400m (n=55) >600m (n=15) >800m (n=6) number of dives 4000 30 70 110 150 190 230 270 310 350 depth (m)

Reducing by-catch – a ‘win-win’ scenario NED Experiment – Watson et al (2002) http://www.nmfs.noaa.gov/mediacenter/turtles/ Standard: J-hooks & squid Trial: circle-hooks & mackerel Decreased leatherback by-catch by 66%! No decrease in target species! J - hook circle - hook

Conclusions Pan-Atlantic movements Focus of specific areas insufficient Epi-pelagic diving behaviour Explains fishery interaction Solution? - Basin wide adoption of methods

Future satellite telemetry work - Major contribution to conservation of pelagic species Long-term monitoring programme - habitat utilisation in Atlantic - rapid assessment of behavioural changes 2. Estimating mortality through satellite telemetry - detecting where mortality occurs - mortality rate