We set off early to Queen Anne’s Battery marina to meet Beth from the University of Plymouth. She guided us to Take the Helm, the university’s 13.5-metre sailing yacht used since 2017 for cetacean surveys. After stowing our gear and a safety briefing from skipper Andy, Beth explained the survey protocols before leaving us in the capable hands of Dr. Simon Ingram.

As we sailed out of the harbour, we practiced estimating distances—an essential skill for recording sightings. Once in open water, we rotated survey roles every 30 minutes: two observers and one recorder at the bow, while others took breaks or steered the boat along a plotted course, which I was surprised (and nervous) to do early on! In addition to marine mammals, we recorded birds, boat traffic, jellyfish, buoys, and litter. The calm seas and sunshine made for great conditions, though glare was a challenge.

Our first day yielded sightings of many Manx shearwaters, a grey seal, and a fleeting harbour porpoise. The highlight came later with three encounters of short-beaked common dolphins, including juveniles bow-riding our boat’s wake—an unforgettable experience. We ended the day moored in Dartmouth, ready for the days ahead.

We were up and readying the boat for our departure at 7.45am. It was another calm day, meaning that we weren’t able to sail without some assistance from the engine. As we headed across Lyme Bay towards more familiar Dorset waters, a sea fog was building, reducing visibility for a time, but it soon cleared to reveal Chesil Beach and Portland in the distance.

We began noticing lots of jellyfish in the water; mainly moon jellyfish but also plenty of blue and compass jellyfish. Despite the favourable conditions, it was fairly quiet in terms of wildlife, with fewer sea birds than the day before and a notable absence of cetaceans. As we rounded Portland Bill, which had been carefully planned to avoid the turbulent tidal races, we saw a large feeding aggregation of gulls and gannets but sadly no sign of any fins amongst them. We continued along the Dorset coast to Chapman’s Pool where we spent the night.

After another long, hot and largely sunny day, we all took the opportunity to cool off with a refreshing swim off the back of the boat before dinner. As the sunlight faded, we spotted a couple of grey seals relaxing in the bay before we were treated to a spectacular sunset to round off the day.

Leaving the stunning Chapman’s Pool behind us, we sailed past St. Alban’s Head and on towards Durlston, where we started to record more auks, mainly guillemots, known to breed along this section of the Dorset coastline. The sea was mirror calm as we approached Old Harry Rocks, then headed towards the Isle of Wight.

Our passage took us south of the island, where once again we happened upon a large feeding frenzy with hundreds of gulls, plunge-diving gannets, and also a great skua getting in on the action. A bit further along, we noticed a tidal front, so decided to follow that for a while.

The day’s highlight came when a shout of “mola mola” came from the surveyors at the front. They had spotted not one but two oceanic sunfish, right next to the boat, no doubt making the most of the bounty of jellyfish.

Heading into Portsmouth, we noticed a change in the bird species again, recording more black-headed and Mediterranean gulls. With boat traffic becoming heavier, it was time to reel in the hydrophone, which we had been towing on a 100-metre cable, to avoid it becoming fouled.

We made our way into Haslar Marina, Gosport, and took advantage of the shore facilities (our first proper shower since Plymouth!) before enjoying a delicious meal cooked on the boat.

Leaving the bustle of Portsmouth behind us, we continued on our easterly heading. A lone seal was spotted bottling nearby, then a flock of 60 common scoter overtook us, flying low across the water in a long line formation. We headed into deeper water, away from the coast and had a wonderful encounter with three harbour porpoises, our smallest cetacean, which stayed in view long enough for everyone to get a good look. These seemingly shy animals have a high metabolic rate meaning they don’t waste valuable energy interacting with vessels, prioritising foraging. Did you know that harbour porpoises spend around 95% of their time foraging?!

In the distance, looming out of the haze, we could just make out an array of wind turbines forming the Rampion Wind Farm. Keeping to the north of the wind farm, we noticed a few gulls, gannets and cormorants before another (or possibly the same) group of common scoter passed again. We travelled as far east as time would permit, turning a few miles before Beachy Head, then doubling back and making our way into Brighton marina. Once safely berthed, we grabbed our swimming kit and headed to the nearby beach for a swim to cool off.

Following a report on social media of a small group of bottlenose dolphins not far from our location the evening before, we hugged the coast as we sailed west for the first time this week. Sadly, our paths didn’t cross with the dolphins, our consolation was in the form of another sunfish, its long fin flapping at the surface. The wind had picked up and was behind us, perfect for sailing, so we unfurled both sails and headed back towards Portsmouth under full sail.

With the increased wind, the sea state also changed. We had a lot more chop and whitecaps meaning detecting cetaceans would be trickier. We continued to record a variety of seabirds including quite a few terns, but marine mammals remained absent, or obscured from sight – perhaps the hydrophone would reveal something different?

Back in Portsmouth again, we noticed some ominous looking clouds which did produce a short shower. We refuelled and cleaned the boat, saddened to be leaving our floating home for the past five days although very much looking forward to a good night’s sleep in our own beds!