First evidence of an important marine migration corridor between Costa Rica and Ecuador
Sanjay, a 53k (117lb) male endangered green sea turtle (Chelonia mydas agassizii), recently made history when he completed a 14-day migration from the Cocos Island Marine National Park in Costa Rica to the Galapagos Marine Reserve in Ecuador.
Sanjay is the first turtle to directly link these two protected marine areas, proving the connectivity of the Eastern Tropical Pacific, as well as highlighting the importance of protecting migration routes.
“It’s truly remarkable,” said Alex Hearn, conservation science director for the Turtle Island Restoration Network, based in California.
“Sanjay knew where he was headed, and made a beeline from one marine protected area to the next.
“These protected areas of ocean are hot spots for endangered green sea turtles, but we also need to think about their migratory corridors between protected areas.”
Sanjay was one of three green sea turtles tagged at Cocos Island in June during a joint 10-day research expedition by the Turtle Island Restoration Network and Programa Testauracion de Tiburones y Tortugas Marinas (PRETOMA) of Costa Rica.
Since 2009, the two organisations have tagged over 100 turtles and several species of sharks in a programme to understand how endangered turtles and sharks use the Cocos Island and Galapagos National Parks marine protected areas, and to see if their is biological connectivity between those new sanctuaries.
Sanjay is the first turtle to have been documented moving between these two marine protected areas and joins several hammerhead sharks, a silky shark and a Galapagos shark that have spent time at both of these reserves.
“Finally seeing a turtle move from Cocos Island directly to Galapagos is absolutely amazing,” said Maike Heidemeyer from PRETOMA. “Especially because preliminary genetic research results suggest that there is a connection between the green turtles at Cocos Island and the Galapagos.”
Green sea turtles, like Sanjay, play an important role in the Eastern Tropical Pacific ecosystem, but little is known about the geographic distribution of juveniles and males, despite the fact that nesting sites for female turtles have been identified in the Galapagos, mainland Mexico and Revillagigedo Islands, as well in the Northern Pacific of Costa Rica.
At Cocos Island, two different populations of turtles occur: the black-to gray coloured Eastern Pacific green turtles (also known as “black turtles”) and Western Pacific populations. Both populations are considered by some to be subspecies, but there is no official taxonomic division.
“These species are protected while they are in the reserves, but as soon as they swim beyond the no-fishing zone, they are being hammered by industrial fishing vessels that set millions of hooks in the region,” said Todd Steiner, executive director of Turtle Island, biologist and co-primary investigator of the Cocos research programme.
“Our goal is to collect the necessary scientific data to understand the migratory routes and advocate for ‘swimways’ to protect these endangered species throughout their migration.”
“The route that Sanjay followed is riddled with longline fishing gear,” said Randall Arauz of PRETOMA.
“Several international initiatives exist to improve marine conservation in the Eastern Tropical Pacific, and its time for these initiatives to translate into direct actions that ultimately protect these turtles from unsustainable fishing practices.”
Satellite, acoustic and genetic information is currently being analysed and will be officially published later in the year.
Sea turtle Sanjay is on the move again, the latest ping suggests that he is headed to green sea turtle nesting grounds at Isabela Island.
Sanjay’s migration track can be seen on this map.