Spotted...!?

A survey from Aberystwyth on September 28th revealed an unusual dolphin. Unfortunately it was not very cooperative, but in appearance it could have been taken for a juvenile bottlenose on its lonesome.

According to the crew, it had emerged quite close to the front of the boat initially, reported to bear an unusual coat of little dark speckles. The boat was called to a sudden halt, but at the speed we were going, it seemed the dolphin was more than spooked and it did not return again. We paused for several minutes, eyeing the ripples and drifts of tides, but no sign.

"It didn't look like a Tursiops," our lead watcher affirmed. I couldn't argue; there was something unusual about the one that got away, but it wasn't overly, strikingly different to a usual bottlenose. But there was another group of dolphins very similar, belonging to the Stenella genus. Its closest member, the Atlantic spotted dolphin, normally inhabits seas beyond the Mediterranean. She wasn't immediately confident that it was one, and for good reason: it was a major rarity anywhere in the north Atlantic.

Of course they then look to me. "Did you get any pictures?" they ask, for which I can't offer an optimistic reply.  No internet information exists on Atlantic spotted dolphin in the UK, or even in Franc. It was not the first possible spotted dolphin reported this year, though none of the reports had been confirmed or photographed, a fate that this one will also share. 

Considering the rare and vagrant Cetaceans known in the UK in the past, it is hardly impossible. Birds are the best example of vagrancy, we've seen "megas" that have flown thousands of kilometres from their native range from western Asia, Africa and America. The UK's sole record of ancient murrelet, a central Pacific bird that will not fly over land except in hurricanes, would have traveled all up the Pacific Coast, along the Arctic Ocean, down the Atlantic through Greenland and all the way over the North Sea to reach the UK. So then the question is why has the spotted dolphin, something which by rarity is hardly comparable to some foreign birds, has not been "officially" seen in the UK before? 

This question is far more easy to answer. The extreme similarity of the Atlantic spotted dolphin to the bottlenose dolphin by default makes it susceptible to being highly overlooked. I saw our dolphin from no more than 100 metres off, albeit silhouetted, but I never would have given it a second look. If it wasn't for the markings, I doubt anyone would have raised an eyebrow. Most dolphins are seen far out to sea, and even binoculars or telescopes might not be enough to see the details. The only truly obviously diagnostic difference are in the spotted markings, which are tricky to see unless in close proximity, and you need a boat for that, and the sacred license to approach them in the first place. 

The issue with many sightings is that well-marked bottlenose, especially if only a dorsal view is seen, could be mistaken. This is supported by the issue that markings usually increase in density as they travel up the animal, so the back could easily be as spotted as the confusion species in question (but if it were to breach, then the rest of it would be obviously unspotted; spotted dolphins should be equally spotted all over except for juveniles).  

It is also worth noting that unlike birds, their complete territory is far harder to survey, and for the most part impossible from land. A speculation was that warming seas could encourage them further north. The eBird report exists here.


*(bearing in mind this is a bit of a generalization, as many dolphin pods are in fact not tolerant of boats at all even in Wales).

**Dedicated surveys only allow a maximum of 5 minutes with each encounter before we must move on, whether it is to keep the survey going or to reduce interference with the animal's natural behaviour.

12th September

The darker morning hours meant that the later it was on the calendar, the more sleep we would all get. For instance, most boat survey departure times were now beyond 6 and 7am compared to the 5am and earlier routine earlier interns had to follow. I don't think it really meant a difference, but there did seem to be some psychological appreciation by the other interns, who seemed much more enthusiastic at getting an extra hour of sleep. It does seem true that getting up at 5am sounds much earlier than getting up at 6am.

12th September was the Aberystwyth survey. The primary benefit was that the boat here, Ma Chipe, was much faster, reaching 14+ knots, in contrast to the 5-6 knots capability of the Dunbar. This meant that it was easier to reach the outer transect survey areas. The relevant SAC areas offshore, both the Cardigan Bay and the Pen Llŷn a'r Sarnau, were split by the Sea Watch Foundation into inner and outer transect regions. The outer transect surveys were just extended versions of the inner, encompassing both the inner and outer areas.

Inner and outer transect maps, courtesy of Sea Watch Foundation.

On board Ma Chipe, there was a bit of misinformation on what area we were surveying however. Whatever the case, we ended up just randomly surveying the Pen Llŷn SAC instead, even though it wasn't strictly part of our main research focus. I don't have a map showing the route we took that day, but I could probably borrow the GPS coordinates for the day if I needed too. There were pessimistic rumours spreading that there were little or no dolphins around this area, supported by the facts that there were far fewer fish than usual. However, of all the recent surveys, I don't think we've ever recorded so many dolphins before.

I'm just going to post head shots because everyone likes those.

An odd thing to note were these random swarms of flies far out to sea. They were mixed swarms of a whole variety of flies, midges, gnats, crane flies and other oddities. We all ended up covered in them whenever we stopped in those areas.

But a small selection of flies present, including the late-flying cranefly Tipula confusa on the far right minus one leg.
Other than that, and the assumption that the top left is some relative of a St Mark's fly, I have no clue what any of these
are.

A shallow reef halted our progress on one of the transects, so we had to take a different route. The clouds started pouring in but some unique sky on offer.

The reef is visible as the calm section between two slightly rougher tides.

Same copyright as other images, just forgot to add watermark.

 A dunlin flying out to sea towards Ireland seemed to serve as an omen to the coming fall migration in the area, and common scoter was relatively common. The weather is starting to drop and it's getting colder by the day. Better get that winter coat out...

4th September

I never found the decently early time of 5am to be either a nuisance or a surprise. I had been up earlier before for pelagic trips, or mere walks, well into the 4am realm. Today was the spontaneously planned Dedicated Search survey, my first real trip with the Sea Watch Foundation. Dedicated Search was a noun that as I learned has become synonymous with "erratic", "irregular" and "impromptu" at the same time. Such a survey erased everything on the schedule for that entire day, summoned all volunteers regardless of what they were doing or where they were, and combined all resources into a (dedicated) search for marine mammal activity. The primary goal was to cover a random line transect point, which offered its own data in terms of spatial use and population density in the local 3 mammal species.

The early start was intended to get all of us on the boat by 6:20am--as it happened it was running a bit late and did not really come until about 6:40, but at least the sky was nice this morning.

Dawn over New Quay harbour.

The sea was thankfully quite flat this morning, with few ripples and remaining mirror-clear for a great portion of the initial few hours. The first 2 bottlenose dolphin sightings preceded the boat boarding and therefore did not make it onto the official sightings forms as more than a notation at the top of the sightings sheet.

A pair harbour porpoises around 7:10am were the first officially recorded cetacean sightings, though 2 grey seals, one hauled on the rocks and a second in the water were seen before hand. Perhaps my only fear was finally seeing a harbour porpoise and not having a camera on hand, which happened in the first 30 minutes! I could, however, be content that at least there was little that could have been "worse" from that point on. A cliff pass added a few land birds to the daily "list" including 2 chough, 3 ravens, jackdaws and 2 red kites, though the Sea Watch Foundation does not keep records of anything avian, and neither does the Marine Wildlife Centre for that matter.

An initial bottlenose dolphin sighting was had at 7:40am along the coastline of Llangrannog of 2 individuals, though we were just over 2km out at sea but Dr. Dussán-Duque judged them to be too far. Yet 10 minutes later the next pair, just over 600m, was selected for photo-ID and behaviour recording purposes. The initial pair revealed other pairs, and then others, totaling 7 adults and 3 calves, perhaps including the 2 individuals that we did not approach earlier. The 4 subgroups merged and split as the encounter came and went, and both feeding behaviour, as well as one adult that was, in all decent terms, punting a jellyfish out of the water. The jellyfish itself was most likely Cyanea lamarckii, a regular species in Wales. There was plenty of photo opportunity if you were lucky to catch them fast enough.

Waving hello?

Does anyone remember the game Ecco the Dolphin where you headbutt blue jellyfish?

With that aside, there was little of interest for the rest of the 7 hours! A 1cy Mediterranean gull was the only notable bird in this first hour, the only of its species recorded throughout. A fairly recent traveler to the south coast, this gull is still relatively uncommon this far north but it is spreading quite rapidly and can't really be called rare any more.

The only other two events of interest was a dead seal, and a "sunfish" which revealed itself to be a quite lost and deflated balloon about 2km out to sea. The balloon, whose design featured Elsa from the near-viral Disney film Frozen, was perhaps owned by a child who quite literally "Let it go". The balloon was, naturally, rescued to save any environmental harm it may have caused.

In other notes, the usual birds were present in small numbers, including kittiwake, guillemot, fulmar, manx shearwater and great black-backed gull. A few swallows, a crane fly, small tortoiseshells, and some other miscellaneous insects seemed to be oddities this far out to sea. It is possible to see migrating birds fly towards shore from over the sea, as these swallows did, but the species only flies towards the UK in the spring when they fly up from continental Europe. I can only guess that they flew over from Ireland, intercepting Wales as they headed towards France.

Great black-backed gull exhibiting the reasoning behind its name.

All in all it turned to be not a bad trip. Those on photo-ID, behaviour and observer duties were left without anything to do beyond those first encounters, save the necessity of having to remember to write down boat data every 15 minutes (this task is done by both primary observer, independent observer, and effort collector to ensure that measurements are consistent and, most importantly, correct).

And, just because I thought it was cool, here is a variant of the common field grasshopper from the Cwmtydu segment of the coastal path above New Quay. This is a hugely variable species, that can be coloured anywhere from green, brown, orange, beige, grey and...apparently pink! I once heard the probability of such a erythristic individual is estimated at 1 in 500. Either way, they are quite uncommon.

Pink variant common field grasshopper.