This summer, I have been fortunate to work with the wonderful Celtic Deep team in Pembrokeshire, Wales. We have spent many days offshore searching for the iconic blue shark; however, this year has required more perseverance than usual. A delay in the arrival of the blue sharks, patchy sightings, and weather cancellations added additional challenges to the fieldwork portion of our studies. My work focuses on the use of non-capture methods to study the genetics of blue sharks.
Although I cannot confidently say the exact cause of this irregular season, as there are so many interacting components, it could be the result of a cold spring. However, I am somewhat comforted in knowing that it has been an unusual year for wildlife in general, not just for sharks. Species of birds and crustaceans have also shown delayed arrivals and irregular sightings this summer. There has also been a large algal bloom in the southwest region which could be affecting the blue shark's local distribution and use of different depths.
The unpredictability of fieldwork, which I have certainly experienced this year, has meant that I have not collected as many samples as I had hoped. But, we have had some fantastic days out on the ocean. The sharks we have been able to interact with have been very inquisitive, allowing me to collect numerous samples from several individuals. The samples will form the basis for a study looking to contribute evidence for using non-capture methods to collect DNA samples from free-swimming sharks and other marine taxa.
Our second project involves trialling a novel method for filtering water samples for eDNA (environmental DNA) studies. Due to the nature of developing novel methods, there has been some trial and error to get this off the ground, and we are continuing to improve our methodology. Still, our eDNA sampling is underway and hopefully we will have some interesting results to share soon.
Despite the patchy season, I have had an incredible time and seen some remarkable wildlife, including a breaching basking shark, sunbathing mola mola, and a cruising porbeagle shark. We have also seen countless baitballs, which can include many species such as common dolphins, fin whales, bluefin tuna and gannets, all feeding on schooling fish such as mackerel and herring.
The fieldwork section of my projects is almost complete. The next step is returning to Newcastle University, where I will conduct the labwork component of the studies. Hopefully, we will highlight pros and cons of our developed methods.
Stay tuned for more updates.