The first fin whale I saw from my own deck was off the shelf edge west of Belle-Ile, in flat calm at six in the morning. A tall, slanted blow, then a long grey back that just kept coming. By the time the dorsal fin showed it was clearly a long way astern of the head, and that is when it sinks in how big a 20-metre animal really is when there is no railing, no tannoy and no naturalist telling you where to look. Just you, a mug of tea going cold, and the second-largest creature that has ever lived breathing fifty metres off the beam.
Most people meet Biscay whales from the deck of a Brittany Ferries ship to Santander. That is a fine way to do it, and the ORCA wildlife officers on board are excellent. But if you are crossing under your own keel, or coasting south down the Atlantic seaboard, you have a better seat than any ferry passenger, lower to the water and able to stop. This is what I have learnt about turning a passage into a wildlife watch.
Why the bay is so rich
The Bay of Biscay covers roughly 177,000 square kilometres, and it is not a uniform basin. The continental shelf runs out gently from the French coast and then drops off a cliff. Off the Basque country the Capbreton canyon, the Gouf, plunges from close inshore to around 4,000 metres, one of the deepest submarine canyons in the world and only about 300 metres off the beach at its head. Where deep cold water is forced up these canyon walls it carries nutrients to the surface, plankton blooms, small fish gather, and everything bigger follows.
The numbers are genuinely startling. Around a third of the world's roughly 90 cetacean species have been recorded in the bay. Aerial surveys put the common dolphin population of the wider European shelf and offshore waters at about 467,000 animals, with the bulk of them in Biscay and off France and Spain. In summer the abyssal plain holds an estimated 10,000-plus fin whales. You are not hoping for a rare fluke of luck out here. You are sailing through a working ecosystem.
What you are likely to see, and when
Different animals keep to different water depths, so where you are matters as much as when.
- Common dolphins, the default. Small, fast, yellow-flanked, and they love a bow wave. A pod will appear from nowhere, ride for ten minutes and vanish. You will probably meet them on the shelf in any month with reasonable visibility.
- Striped and bottlenose dolphins, common over deeper water and around the shelf edge.
- Fin whales, the headline act, most reliable from June to September when they concentrate over the deep water. The April-to-October window is the broad season, July to September the peak.
- Pilot whales, often logging at the surface in groups, over the deeper basin.
- Sperm whales and the various beaked whales (Cuvier's, the secretive ones), strictly deep-water animals tied to the canyons. You need to be over thousands of metres, and you need luck.
- Harbour porpoise close inshore, easy to miss because they are small and shy and never bow-ride.
The single best tactic is to time a passage so that you cross the shelf edge, where the depth jumps from a couple of hundred metres to over a thousand, in good daylight and a calm sea. That break is where the action concentrates. If you are planning the big jump south, my notes on crossing the Bay of Biscay in a small boat cover the passage itself; treat the wildlife as the reward for picking a settled spell.
How to actually watch from a moving boat
Watching from a 35-foot yacht doing six knots is a different skill from standing on a ferry's monkey island. A few things make the difference between a blank day and a logbook full of sightings.
Scan the horizon, not the water near the boat. A whale gives itself away by its blow, and a fin whale's blow stands several metres tall and hangs for a moment. You will see that long before you see the animal. Sweep slowly across the far distance with the naked eye, then bring the binoculars onto anything that catches your attention. Glassy patches, slicks and rafts of feeding seabirds are all worth a long look, because gannets and shearwaters working the surface usually mean fish, and fish mean predators below.
Get the sun behind you when you can. A blow is far easier to spot lit from behind your shoulder than squinting into glare. Early morning, before the wind gets up and chops the surface, is prime time both for flat water and for low light that makes blows obvious.
If something big surfaces, do not chase it. Hold your course and speed, or come off the throttle and let it come to you. Curious dolphins will close the gap themselves; a frightened whale will simply leave. Keep your distance from any animal that is clearly not interested, give mothers and calves a very wide berth, and never put yourself between the two.
Telling them apart
Half the pleasure is putting a name to what you see, and from a small boat you have to work fast before the animal is gone. A few field marks do most of the work.
The blow is your first clue with the big whales. A fin whale's blow is tall, narrow and vertical, several metres high, and it hangs in still air. A sperm whale blows forward and to the left at a low angle, a giveaway once you have seen it. If you see a blow at all, you are almost certainly looking at a baleen or sperm whale rather than a dolphin, because dolphins rarely show a visible spout.
Then the surfacing pattern. A fin whale shows a long, low grey back and the dorsal fin appears only well after the head has gone under, because the animal is so long. A minke is smaller, with the fin and the back showing together in a tighter roll. Pilot whales loiter at the surface in groups with bulbous heads and a low, swept-back fin set well forward. Sperm whales lie log-like at the surface between dives and then lift the flukes clear when they sound.
With dolphins it is mostly about size, markings and behaviour. Common dolphins are small, fast and have a yellow hourglass on the flank; they love a bow wave. Striped dolphins are similar in size with a bold dark stripe running back from the eye. Bottlenose dolphins are bigger, greyer and less inclined to play. Risso's dolphins are heavily scarred, almost white in old animals, with a tall fin and a blunt head.
You will misidentify plenty, especially at distance and in a chop. That is fine. Note what you are sure of, flag the rest as probable, and the picture builds over a season.
Birds are part of the same picture
The seabirds tell you where the food is, and Biscay is a seabird highway as much as a whale one. Gannets plunge-diving in numbers, manx and great shearwaters shearing low over the swell, storm petrels pattering in your wake at dusk: all of it points at the same productive water the cetaceans are using. If birds are the bit of Biscay wildlife that hooks you, the islands inshore are the place to dig deeper, and I have written separately about birdwatching the French Atlantic islands by boat, where you can land and get close to breeding colonies.
Keep the log, mind the rules
Note what you see, where (a lat-long and a depth), and roughly how many. Citizen-science records from sailors genuinely feed the surveys; over a ten-year stretch of such data seventeen cetacean species were logged in the bay. It costs you a line in the logbook and it is worth doing.
There is no licence needed to watch whales from your own boat, but there is a code of conduct, and the spirit of it is simple: you are a guest. Approach slowly and obliquely, never head-on. Do not corner an animal against the shore or your own hull. Keep groups together. A sensible working distance is well over 100 metres for the big whales, closing only if they choose to. For the wider picture of where you can and cannot go on the French coast, the rundown of France's marine reserves by boat is worth reading before you set off, because some of the richest water sits inside protected zones with their own restrictions.
Biscay has a reputation for ferocious weather, and it earns it in a gale. But on a calm summer crossing, with the shelf edge sliding under the keel and a blow on the horizon, it is one of the great wildlife theatres in Europe, and you have the best seat in the house. Slow down, look up, and let it come to you.
