1. 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

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

3. Pacific leatherback turtles face extinction
Nature / Vol. 45 / 1 June 2000 /
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)

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

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

6. 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

7. 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:

8. Horizontal movements – importance of frontal features?
Ferraroli et al (2004) Nature 429:

9. 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:

10. 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)

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

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

13. 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