This trip aboard the sailing ship PangeiaThe first stage of the Recife-Ilhabela expedition, between Ilhabela, on the north coast of São Paulo, and Florianópolis, on the north coast of Santa Catarina, was planned to complete the largest effort to collect sun coral larvae ever undertaken in Brazilian waters, which took place between Recife, in Pernambuco, and Ilhabela, in São Paulo (link to Recife-Ilhabela expedition).
This time, however, in addition to the coastal sampling points, we had the challenge of navigating ocean waters 70 nautical miles from the coast (about 130 kilometers), right on the break of the Continental Shelf, where the sea depth reaches 200 meters. Our objective at this distant stop was to collect water samples next to the oil extraction platform called Mexilhão.
Studying the waters adjacent to platforms is very important in understanding the dispersal dynamics of coral larvae that may originate from individuals attached to the submerged structures of these offshore production units.
The sailing ship PangeiaThe boat, commanded by Captain Beto Fabiano, left the shelter of Santa Teresa cove at around 11am with a moderate wind blowing from the east quadrant and only arrived at the first collection station, the tip of Pirabura, at the end of the day, with the sea already rougher due to the constant wind and skies heavy with rain.
These weather conditions have added even more symbolic elements to this place famous for having been the scene of one of the greatest disasters in the history of navigation. Well, there near the point of bare rocks battered by the waves about 15 meters below the keel of our sailboat was the wreckage of the Spanish ship Príncipe de Asturias .
The boat sank when it collided with the shores that we could clearly see 50 meters from the Pangeia while we were making the first of a series of 15 plankton trawls planned for the six-day trip.
In the early hours of March 5, 1916, adverse weather conditions, with low visibility due to fog, led to some navigational errors that resulted in the 150-meter-long steam liner crashing into the rocks off the coast of Ilhabela and subsequently sinking. Unfortunately, the accident claimed the lives of more than 400 people and is the largest shipwreck in the South Atlantic.
Our motivation for collecting water samples over the wreck of the Príncipe de Asturias in an area of delicate navigation in rough seas comes from the evidence that submerged artificial structures, especially shipwrecks, form very suitable substrates for the recruitment of larvae and the establishment of new sun coral colonies. These substrates act as stepping stones for the invasion of the species.
It was a relief to finish trawling and start moving the sailboat away from the coast. We were sailing under full sail and making good speed. It was almost dark when we set off straight for our furthest objective, the Mexilhão platform. However, the increasing intensity of the easterly wind and the waves created by it were coming right at our bow, a condition in which the boat suffers a lot from the waves and doesn't develop good speed.
At around 7 p.m., when the waves started breaking over the deck, we decided to return to Ilhabela to spend the night in a shelter until the sea conditions improved. It was a tense ride, a moonless night and a lot of rain, but we managed to get safely into Saco do Sombrio.
The next day we continued our journey and that same night we collected more distant waters, near the Mexilhão platform. It's very interesting to pass the plankton net in the middle of the vast ocean, in the darkness of night and with the myriad strong lights of the platform as a reference.
That same night we headed back towards the coast, passing Laje de Santos, from where we started a series of coastal stations, the last one being on the coast of the Arvoredo Biological Reserve, just north of Florianópolis.
In their on-board routine, researchers Yann and Henrique carried out the tasks of passing the net, collecting water samples for filtering the plankton and packing and cataloguing all the material collected with precision, under any sea conditions.
We entered the north channel of Santa Catarina Island at night. A tense navigation due to the intense traffic of fishing boats and the presence of shallows. When we finally arrived at the shelter, in the quiet town of Santo Antônio de Lisboa, we had the good feeling of completing an unprecedented scientific mission: collecting water samples for the study of sun coral larvae, from Recife, in Pernambuco, to Arvoredo Island, in Santa Catarina. An important step in improving models of invasive coral dispersal.
Luciano Candisani
