Click-Fest

50, 25' N, 40,11' W. Wind F4-F5, swell c.4m. Ship speed 9 knots. Occasional rain/hail/sleet/snow/frozen-mist showers. Sea temp 12C (but plummeting to 7C occasionally), air temp, 5C.

It was a lot 'milder' today than previous days - thankfully the crow's nest windows are no longer fogging up, and I was able to wash the salt off them without the window cleaner freezing. It was a productive day for cetacean detections, thanks to the wonders of PAM (Passive Acoustic Monitoring). With a following sea and a clean sound, Alessandro recorded pilot whales, unidentified dolphins and sperm whales frequently throughout the day. The sperm whale clicks were coming in at such a high rate that they crashed the computer at one point. These detections were not matched with sightings despite 7 hours of effort, given that conditions were tricky and we are dealing with deep-diving species. I did spot an unidentified large whale only 300m from the ship - it was most likely a fin whale given the powerful blow, large fin and brown hue to its back.

Pilot Whale whistles visualised on the spectrogram from the hydrophone (Alessandro Pierini)

Pilot whale burst pulse sound (function not really known, but VERY loud!) on the left and sperm whale clicks (used for searching for prey - echolocation) on the right (Alessandro Pierini).

There are groups of sperm whales clicking away in a mad frenzy at the moment - it sounds like a load of people breaking stones with little hammers, with the occasional dolphin whistle thrown in (most these are at a frequency too high for me to hear, but everyone else can hear them fine!). It is surprising that we have so many detections of cetaceans out here over the abyssal plain, given it has a reputation for being a 'desert'.

Profile of the water column and benthos from the EK60 - an active acoustic device which is used to record fish / plankton during the transit. Biomass can be estimated from the 'marks'. No clear marks on this screen-grab, but there are some fish near the surface. The abyssal plain is about 4200m deep here with the odd rocky feature.

Birdyology: Emily recorded kittiwakes (groups of >40 doing sudden climbs and dives), little auk, Brunnich's guillemot, great skua, lesser black-backed gull and fulmar.