Longer days bring whales to our waters
Spring is certainly underway here in Scotland and the signs are everywhere. Seabirds have returned to breed after a long winter at sea, wildflowers have begun to bloom and whales have been spotted back in our waters. It is a vital time for marine life in Scotland as the sun begins to shine with increasing ferocity and our seas begin to warm.
But why does this mean that we start to see more marine life in our waters?
In spring as the days start to lengthen, and the water warms, our seas become a great environment for life to grow and bloom. In the spring, more light becomes available and stratification of the water column occurs as increasing temperatures warm the surface waters (referred to as thermal stratification). This means that vertical mixing is reduced and nutrients are concentrated in the uppermost layer of the ocean where the light can reach, known as the euphotic zone. This layer, therefore, has comparatively high light and nutrient content allowing rapid phytoplankton growth. Phytoplankton, the collective term for microscopic marine algae is the base of the food chain.
Due to the increased light, temperature, and nutrient levels in springtime phytoplankton can double at least once per day, allowing for exponential increases in phytoplankton stock size. Phytoplankton form the base of virtually every ocean food web. In short, they make most other ocean life possible, from other plankton and small fish, all the way up to larger animals such as whales. It is the abundance of these microscopic plants that draws marine megafauna like minke whales and basking sharks to Hebridean seas every spring. Check out this incredible video of sandeels below - sandeels feed on plankton and are themselves the favourite snack of some of our favourite marine species, like the harbour porpoise and puffins!
Springtime can really lift the spirits, with the sights and sounds of the natural world 'waking up' or starting afresh all around us. Over the last few weeks, we have received many exciting reports through Whale Track, with the year’s first sightings of minke whales and basking sharks, species that are known to migrate into our waters. Our Marine Biodiversity Officer Becky spotted her first minke whale of the year on the 3rd of April from the northwest tip of Mull.
“After watching for a couple of minutes we spotted an area with lots of seabird activity. It was a sunny and calm day so we could also see tide lines on the surface of the water which tend to be great areas to watch for possible cetacean sightings. Just 5 minutes later I shouted with excitement as a minke whale surfaced right in the middle of my binoculars. My first minke of the year!”
- BECKY DUDLEY, MARINE BIODIVERSITY OFFICER
Minke whales have also been reported on Whale Track from Ardnamurchan Lighthouse, the Isle of Rum, and the Isle of Barra in the Outer Isles. It is not just minke whales that have returned to our waters. We also had an exciting report of a basking shark from the Isle of Canna on the 15th of April. This species comes to our waters to feed on the high concentrations of zooplankton that can be found here. Puffins have also returned to the Isle of Lunga to breed after spending their winter out in the open ocean.
Help us get back on the water at this crucial time
We have been collecting this information on the marine life in Hebridean seas for over 18 years, but due to the pandemic, we were unable to gather vital data at this crucial time of year last spring. 2021 is set to be another challenging year for our boat-based research and we are calling on your help to get us back on the water once more. It is only through this long-term monitoring that we are able to identify trends and changes to the marine environment so it is essential that this monitoring continues!
ONE DONATION, TWICE THE IMPACT
We have been selected to take part in the first-ever Big Give Green Match Fund! Launching on Earth Day on 22 April, for one week only, we have an amazing opportunity to help HWDT get back out on the water this spring and continue our vital work to monitor and protect cetaceans on the west coast of Scotland.
There is also a Joint Warrior Exercise taking place in May and it is crucial that we are able to survey at this time to monitor the potential effects of sonar on the cetaceans in our waters.
Every pound you donate will be DOUBLED by The Big Give, providing a potential cash boost of £5,000 to protect cetaceans in areas of critical habitat here in Scottish seas.
With one donation, you can double your impact. Please help us get back out to monitor Hebridean seas this spring.