Oʻahu line transect surveys - that's a wrap!
Written by Claire Lacey
There have been some big milestones over the last month or so, here at "spinner dolphin HQ"!
Spinner dolphin, photographed by Claire Lacey under NOAA Research permit 21476
For the past year or so, we've been conducting line transect surveys around the entire coastline of Oʻahu, collecting data that will be used to estimate how many spinner dolphins use these waters (see our project pages, and previous blogs: Counting dolphins and spinner dolphins on tour )
Work on island-associated spinner dolphins, such as those found in Hawaii, often focusses on the more sheltered, leeward side of the islands - the side which is protected from the prevailing winds. There are good reasons for this - not least that it is it easier to work here, as the waters are generally much calmer. For this project, however, which was being conducted in conjunction with NOAA / PIFSC, we are interested in looking at the full coastline. For any readers familiar with the prevailing wind and sea conditions on Oʻahu - you'll know that this means surveys of the North Shore and windward side of the island need to be timed very carefully!
It had taken many months before the combination of boat logistics, personnel availability, COVID restrictions and appropriate seasonal conditions have all coincided in such a way that our North Shore surveys have been possible, but finally in May 2022 things all came together. Research teams from both MMRP and NOAA / PIFSC collaborated to maximise the beautiful conditions we had for a few weeks allowing us to complete our survey work.
Surveys were fruitful, with plenty of sightings, including some of the largest group sizes we've seen on this project so far.
Spinner dolphins in a shallow sandy bay, the type typically used for resting by island associated animals. Footage taken by a GoPro, deployed from the research vessel, under NOAA research permit 21476.
Whilst this is the end of the Oʻahu fieldwork phase of this project, work continues! Keep an eye out for future blogs detailing surveys which will be happening on Hawaiʻi Island later during the summer; the spinner dolphin Facebook page for more regular field updates, and, of course, hold out for the results of this work which will become available soon!
Map showing all of our boat routes since starting this project - more than 6000km all in!
(I would very much like to thank collaborators at NOAA / PIFSC , colleagues from MMRP and elsewhere at HIMB, and all of the field volunteers and interns who have helped out on this project. I literally couldn't have done it without you!)