A collaborative study between several institutions aims to monitor young specimens of two shark species whose breeding area is located in the Galapagos Islands in order to know their habitat and if they live together.
Twelve acoustic receivers in the waters that bathe Puerto Grande, on the Ecuadorian island of San Cristóbal, will be in charge of receiving information on how the marine reserve protects them during their first months of life and during their migrations.
To that end, dozens of hammerhead sharks (in “danger”, according to the International Union for the Conservation of Nature) and blacktip reef shark were “marked” with electronic devices.
“We can know if the sharks are going to other countries, because this system can be registered in other points. The interesting thing is that we are now studying newborns, because before we did it only with adults, “Eduardo Espinosa, who is in charge of the marine ecosystem monitoring program at the Directorate of the National Park of Galapagos (PNG), told Efe.
Located 1,000 kilometers west of the Ecuadorian coast, the Galápagos are a living laboratory in terms of biodiversity, with a multitude of endemic species of fauna and flora due to their privileged climatic and geographical conditions.
The study, carried out by the San Francisco University of Quito (USFQ) and the Galápagos Science Center in collaboration with the PNG, seeks, in turn, to answer the question of how both species coexist.
In declarations to Efe, the researcher of the USFQ and the Galapagos Science Center, Alex Hearn, explained that many sharks approach the shore to give birth and then “the babies are raised between mangroves and coastal lagoons until they reach a certain size”.
This is the case of Puerto Grande, whose marine lagoons favor the presence of offspring that hide in their bottoms from predators.
Through the acoustic signals collected by the receivers, you can locate the position in which the specimens are found and study their movements inside the bay during the period when there is more presence of young sharks in the archipelago.
“We want to know why they are there concentrating and if the place has certain special characteristics that favor reproduction and its development in the first months,” Espinosa said.
Although this research has been carried out for several years, this 2019 account, for the first time, with a team based in San Cristobal Island, which began to study migration movements when there were few copies and has reported an increase in the number of offspring since last February.
Among the members of this team there is an American, Sal Jorgensen, of the Research Institute of the Bay of Monterrey, in California, as well as another Ecuadorian scientist, who are accompanied by a group of postgraduate and undergraduate volunteers.
“This year, the study has hit a quantitative leap. In the last three, four years what we have done is to monitor four or five areas where we thought there was breeding, but now what we are doing is expanding that, we have eight sites in addition to those that we monitor with drone, which go up to 24 “, Hearn insisted.
All with the intention of predicting where more breeding areas could be found in other islands of the archipelago.
They also seek to identify if the same females are returning to the Galapagos year after year to have their offspring, as well as the way in which the two species share space and “their levels of stress, growth and mortality”.
The research, which starts from the hypothesis that sharks compete with each other for space, will elucidate about “what spatial division is like, if it exists”.
The study, Hearn added, tries to discover “some behavior of thermoregulation” among young sharks, since most of these animals are cold-blooded and, therefore, are not able to regulate their temperature internally, but rather to search cooler or warmer waters.
In this way, they have placed in all sharks “marked” small sensors to measure not only the general temperature of the bay but also the areas they occupy.
Another objective is to estimate the population of specimens of both species found in Puerto Grande.
“In any case, for the blacktip reef shark we are talking about hundreds and hundreds of individuals. The hammer no, they are less where we are, “Hearn emphasized. (I)