No one said a word as the ship swung hard to the right. The wind whistled loudly, only broken by the repetitive clink of metal tapping metal. I scanned the surface of the water for a few seconds which felt like minutes. Then, the unmistakable sound of a blow. I had to push up against the railing to see it. There was the fin whale, parallel to the boat, unharmed. The light glistened against its showering blow which dissipated to reveal its huge size. I too let out a huge sigh of relief and fell back off the railings. Looking around I could see relief in the eyes of the others on board. Our boat had nearly collided with a fin whale. Ironically this problem was exactly what brought me to these waters in the first place.

Over the next 48 hours I was about to explore a stretch of water that meets the western coast of France and the North of Spain, waters known as the Bay of Biscay. If you chat to locals, they will tell you these waters have a violent reputation for swallowing boats. Captains will say it is one of the busiest bays for marine traffic. Conservationists will say it is the cetacean hotspot of the world. I was travelling this bay as part of a survey team identifying areas where dolphins and whales are vulnerable to help push for their protection.

One third of the world’s cetacean species can be found in this bay. Deep diving sperm whales, ocean giants like fin whales and super pods of dolphins call this place home. Out of the 18 species that can be found here, surely we would see a few? As we pulled away from land I began recording. First up, porpoise. Porpoise everywhere. A taste of what’s to come. An hour in and the wind was now in full force. On the starboard side, a super pod of common dolphin greeted our bow. There must have been more than 100 of them effortlessly flying through the white capped waves. Then a towering blow on the horizon, then another. Fin whales. Before I knew it we had 20 fin whales and counting. A minke whale and her calf appeared closer to the boat. Followed by another pod of dolphins, this time striped. The bay was alive with whales and dolphins, and I was thrilled by what I was seeing. However, little did I know there was significantly more to come. The richness and diversity of whales found in this bay comes from the different environments it offers. These include shallow waters, deep sided submarine canyons and extensive abyssal plains. This is where dense cold water carries lots of nutrients some 4,000m below the surface. Here you can find deep diving species like beaked whales, sperm whales and squid. As we approached the coast of Spain we headed over two canyons, known as Torrelayega and Cap Breton Canyon. I had been on deck for six hours. I waited until my camera battery was flat before dashing downstairs to change batteries and grab a sandwich. As I ran below deck my gaze stayed fixed on the windows where, to my surprise, I spotted a slate grey to rusty brown cetacean resting on the water. I couldn’t believe my eyes. My first ever Cuvier’s beaked whale, a specialist deep diver renowned for being elusive. Relative densities of Cuvier’s beaked whale in the bay are some of the highest in the world but it was still a real moment of celebration for me. 

I ran back upstairs to eagerly add the species to my now extensive list of cetaceans spotted. Unfortunately, not long after this encounter, we had the close call with that fin whale. Large ships create something called a ‘bow null effect’, where the engine noise is blocked by the bow, creating a quiet zone in front of the vessel. This leaves whales unaware of the approaching threat. There are an estimated 9,000 fin whales in the northeast Atlantic and many of these are found in Biscay, particularly in August and September as they use the waters to feed, migrate and give birth. They are found predominantly along the shelf edge, in the deeper waters and over the abyssal plain. 

Concerningly, the species has been in decline in the Bay of Biscay since 2004 and it isn’t clear why. Just as we see on land, human and wildlife overlap is real. It is thought the high level of marine traffic in the bay may be playing a role in the decline. Collisions are not uncommon. Worse still, no one knows the true extent of which we strike whales. Biscay is a large expanse of deep water and very few carcasses wash up on the shore. Scientists are reliant on ships reporting a strike or near miss. The crews on many ships are unaware that they have hit a whale, only discovering the fact when they arrive in port with a carcass draped over their vessel’s bow. 

As we edged closer to land, I was left with mixed emotions. In the 48 hours it took to cross this beautifully wild bay, I had seen more than 400 cetaceans, including the elusive Cuvier’s beaked whale, minke whale, striped dolphins and more than 50 pilot whales. But our close call was a sobering experience. I couldn’t help but wonder how often these incidents occurred and whether we truly have a grasp on how our increasingly busy marine highways around the world are putting cetacean survival at risk.