Each project is designed to answer specific questions which, when brought together, provide us with a good overview of the situation of sharks in the region. This information is then used in discussions with stakeholders and authorities in order to design management strategies which will help maintain populations whose status is healthy, and to recover those populations which are declining.

Preferred sites and connectivity

Our ultrasonic tagging shows that all shark species studied so far display some degree of site fidelity. These sites tend to be very specific, so that ultrasonic receivers deployed only a few hundred meters apart can often show very different patterns of presence-absence. Hammerheads and Galapagos sharks both seem to prefer these sites during daytime hours, displaying only sporadic presence at night.

There also seems to be a high degree of connectivity between sites, but within each Marine Protected Area. In the Galapagos islands for example, we found that after 12 monthds, 16 from 18 tagged hammerheads displayed movements between a site in Wolf island and another site at Darwin island, some 30 miles distant. Several individuals moved back and forth between islands throughout the year.

April and May seem to be months where less hammerheads are recorded in Galapagos, but where the greatest numbers are recorded in Cocos islands. Are the Galapagos hammerheads migrating to Cocos. Preliminary evidence suggests that they travel there directly, spending as little time as possible in the open ocean. But do males behave in the same fashion?

Diving behavior of hammerheads tagged in both Galapagos and Malpelo suggest that these sharks spend most of their time in the first 50 meters of the water column, but that are capable of carrying out relatively short dives to depths of several hundred meters.

Continuous tracking

Several sharks have been tracked continuously over a 48 hour period. We expected hammerheads to show similar patterns as those studied in the Espiritu Santo seamount of Baja California in the 1970s, where they swam for up to 20 miles in a straight line out to sea every night to feed, and returned at dawn along the same line. However, in Galapagos, they seem to simply circle around the coast continually, and occasionally make short forages (2 miles) into the open ocean at night. In Malpelo thhey seem to move further offshore. Is this related to local food abundance? A Galapagos shark tracked in Wolf, appeared to patrol the entire island during the day, but rested at particular spots at night, never straying more than a few hundred meters from the coastline.

Galapagos sharks migrated large distances in many directions from Darwin island in Galapagos, one individual travelled over 1500 km in a northwesterly direction out to sea, while another travelled from island to island, southwards into the centre of the Archipelago.

Overall, both hammerheads and Galapagos sharks seem to display two distinct behaviour patterns strong site fidelity with absences at night, and migration between sites. But do they only display site fidelity, or can we identify biological hotspots where they aggregate preferentially? And if so, is it only sharks or does the entire pelagic assemblage display similar preferences? And what triggers movements from one site to another? All these questions form part of our ongoing research.

Next steps

• The inclusion of researchers on the genetics of sharks into our team, who will be studying the connectivity of shark populations throughout the region.

• Some of our partners are in the process of developing observer programs and landings inspections, to understand the impact of artisanal and industrial fishing on shark populations in unprotected areas.

• Our array of receivers will be expanded to include areas on the continent.

• New studies on the giant manta and the ocean sunfish.

• Studies on juvenile habitat for key shark species.