1. The Eastern Tropical Pacific Ocean Seascape
Cocos Island (Costa
Rica)
Malpelo Island
(Colombia)
Galapagos Islands
(Ecuador)
Also Coiba & Las Perlas (Panama)
Gorgona (Colombia)
Isla de la Plata, Machalilla (Ecuador)
2.1 million km2

2. Why sharks?
•Sharks are a key group in the marine ecosystem
•Apex predators, drive natural selection processes
•Distinct evolutionary group from bony fishes
•Slow growth, late onset of sexual maturity, low
fecundity – intrinsic characteristics which make sharks
vulnerable.
•Recent studies have shown declines in shark
populations in almost every single population studied
Internal reproduction and live young (mostly).

3. Threats to shark populations

4. Focus: Research Species
Sphyrna lewini
Carcharhinus galapagensis Rhincodon typus

5. Migramar: a regional network
www.migramar.org

6. Focus: Research Questions
Nations encouraged to develop Shark Plans of Action to manage and conserve
their shark populations
• How to delimit stocks?
• No baseline from which to follow trends
Do hammerheads display residency at particular
sites?
Do hammerheads move between sites?
Do they display synchronous behavior?
Is their connectivity between MPAs on a regional
scale?
What are the mechanisms behind site preference
and migrations?

7. Shark Tagging: ultrasonic coded tags
VEMCO V16 coded
tags. Emit train of
pulses at 69 KHz.
Tags are attached to darts and placed on pole
spears. Free divers descend onto sharks and VEMCO VR2 listening stations
insert tag behind the dorsal fin, at a distance (and temp logger), deployed
not greater than 50 cm from the shark. on subsurface moorings

8. Shark tagging: Manual tracking

9. Shark tagging: Satellite tags

11. Shark tagging: Visual Census

12. Ultrasonic listening array in Galapagos
Darwin
Wolf
Roca Redonda
Marshall Point
Cousins
Gordon Leon Dormido
Nameless
Academy Bay
Seamount 90

13. Overall animals tagged in Darwin & Wolf
Species Ultrasonic SPOT/SPLASH PAT Tracking
Hammerhead 149 14 - 7
Galapagos 23 4 12 1
Whale Shark 5 24 1 0
Silky 7 5
Blacktips 7 6

14. What have we learned so far?
•Hotspots and site fidelity
•Seasonal changes in abundance
•Nocturnal foraging behavior
•Movements between islands
•Long distance migrations

15. Hotspots and site fidelity
Tagging data showed the same
preference for east coast
Census data showed greatest abundance in January, and
always on eastern side of Wolf

16. Hotspots and site fidelity
Steel pompano
Crevelle and green
jacks
Galapagos shark
Scalloped
hammerhead shark
Bottlenose dolphin
Snappers
Yellowfin tuna
The largest abundances of species were along the eastern
coast of the island.

17. Manual Tracking
The Galapagos shark patrols the entire island each
day, never more than 200 m offshore, but it
prefers the area between Shark Point and Rockfall
The hammerhead hangs around Shark Point
during the day, but heads out to sea at
night, making deep dives (foraging?)… similar
pathways each night… how does it navigate?

18. Hotspots and site fidelity
N
The Arch “hotspot”
Proposed predominant
Female hammerhead left current direction
Darwin Island 4 and Spent next three
arrived at Wolf 7 Dec weeks between
2008. Rockfall, Shark Point,
and East Bay
Detected at Elephant Rock (ER) at 1312
hrs and stayed within range of monitor for
only 24 min

22. Inter-island movements Loss of Darwin
Arch Monitors
109
107
105
103
101
99 Wolf
97
95
93 Cocos
91
89
87 Darwin
85
83
81 Roca Redonda
79
77
75
73 Malpelo
71
69
67
65
Shark Number
63
61
59
57
55
53
51
49
47
45
43
41
39
37
35
33
31
29
27
25
23
21
19
17
15
13
11
9
7
5
3
1
02-Jul-06 10-Oct-06 18-Jan-07 28-Apr-07 06-Aug-07 14-Nov-07 22-Feb-08 01-Jun-08 09-Sep-08 18-Dec-08 28-Mar-09
Date

23. Regional Connectivity
•Three sharks from Galapagos migrated to Cocos (one also returned)
•Three sharks from Malpelo migrated to Cocos (one continued to Galapagos)
•No apparent connection Galapagos north vs. Galapagos centre
•Connectivity with coastal areas?

24. The next step – ontogenetic migration?
Cocos ?
Ecuador ?
Mangrove bays?