With a few hours to spare before catching my return flight, we did one last survey of the Islas Paridas, but only sighted one group of bottlenose dolphins. Once inside the estuary we observed two more groups.
This wraps up our expedition. In all, we surveyed for 12 days, covered 1034 km, had 1 visual sighting of humpback whales and had 4 acoustic encounters with singers. It has been 15 years since we first surveyed these waters in the boreal season in 2001-2003, with similarly low encounter rates, suggesting there hasn't been an appreciable increase of the population using the Gulf of Chiriqui (unlike the population using this area during the austral season, which is increasing in leaps and bounds). We will prepare a report for presentation at the next Scientific Committee meeting of the International Whaling Commission, as part of the ongoing assessment of North Pacific humpback whale populations.
Our research in Panama is conducted under MiAmbiente permit SE/A-79-17. Islas Secas Resort provided logistical support.
Day Twelve, March 5, Bonus day two — a trip to Islas Contreras, Montijano wind, two elusive whales, and bottlenose dolphins
Our last full day of the expedition was spent surveying the small island group to the east of Islas Secas known as Islas Contreras. On our way there (under a head wind locally known as “Montijano”) we spotted two whales traveling together, keeping a low profile. We slowly approached them as we observed them for a surfacing interval. However, we were unable to relocate them, and because we didn’t get good looks we had to record them as “species unidentified”. Nearly simultaneously, we spotted a small group of bottlenose dolphins in the area that appeared to be of the “oceanic ecotype”. These dolphins were quite large and darker in color than the coastal group.
We had planned for 10 days of survey to account for bad weather days. But conditions have been so good that we’re hoping to continue surveying until the last possible minute (11 am on Tuesday).
In the absence of whales today, and to keep ourselves motivated, we decided to capture a couple of video clips of abundant gelatinous zooplankton that we encountered during our hydrophone dipping stations. We’re curious to receive species identifications from among our expert colleagues.
Day Ten, March 3, The land-sea breeze, a loud male singer in rough seas, and a trip to Islas Paridas
We are fortunate that the Gulf of Chiriquí is situated in a wind shadow while the Gulf of Panama to the east and the gulfs of Papagayo and Tehuantepec to the west endure sustained strong winds this time of the year.
Chiriquí is located in a shadow of relative calm, while the gulfs of Panama to the east and Papagayo to the west endure sustained “gap winds” crossing from the Caribbean through mountain gaps this time of the year. Image from https://earth.nullschool.net/#current/wind/surface/level/orthographic=-82.62,6.44,2242/loc=-82.312,8.192
However, the high pressure that dominates over Central America this time of year means that a local land-sea breeze develops twice a day very predictably. Like clockwork every morning around 7:30 am we get a breeze from land and around 3:00 pm we get an ocean breeze. This morning the breeze got a little intense while we were on transit to the the Islas Paridas for a survey there so we thought we were going to have to abandon that plan and return to the Secas. But not before doing an acoustic station with our hydrophone. As luck would have it, the song of a male humpback whale came very loudly through our earphones (it probably was within a few hundred meters from us). With a mix of excitement and disappointment (as we knew we would not be able to do much work with this whale in rough seas) we sat still, waiting for it to come to the surface so that we could at least catch a glimpse. But it stopped singing and we were unable to locate it visually at the surface among the white caps, so after about 45 min we decided to move on.
But by then the breeze had quieted down and Chanin, our captain, decided we could resume our original plan to survey the Paridas. We plied these waters in excellent weather conditions but without sign of humpback whales.