‘DEEP DIVERS IN DIVERS DEEPS’: CUVIER’S BEAKED WHALES


Cuvier's Beaked Whale, Bahamas (BMMRO / Charlotte Dunn)

‘DEEP DIVERS IN DIVERS DEEPS’: CUVIER’S BEAKED WHALES

JOURNEY TO THE WORLD’S MIDNIGHT ZONE

Please join me in a dive down from the sparkling surface of the turquoise sea to the twilight zone at 200 meters. You’ll pass plenty of sea-life on the way: manatees grazing on seagrass just below the surface; reef fish, barracudas, reef sharks, mahi-mahi, maybe an orca at 100 meters. Other familiar creatures that are found even lower include a few reef fish, some shark species and green sea turtles. You are now running out of clear light.

Cuvier's Beaked Whale, Bahamas (BMMRO / Charlotte Dunn)

As you descend from 200 meters the waters become murky, then inky. The variety of inhabitants and their numbers are gradually decreasing. There are eels, some sharks, squid, stranger deep-water creatures. You may be surprised to see familiar bottlenose dolphins, recorded as diving nearly 300 meters. At 332 meters you will equal the deepest point any human being has ever scuba-dived (Ahmed Gabr 2014). There is little light, but you still have a long way to go to reach your goal.

Dolphin dive depth (Neal)

Descending still deeper, species and numbers continue to thin out. Around the world the limits of larger recognisable species is being reached – more shark species, tuna, chinook salmon, emperor penguins, swordfish, the few corals that can survive the depth. As the light fades to black, giant creatures and strange fish abound. Huge crabs. Sunfish. The (no-longer-extinct) Coelocanth. Massive octopuses. 

Cuvier's Beaked Whale, Bahamas (BMMRO / Charlotte Dunn)

Deeper down, nearing 1000 meters now, there are still some familiar species. Leatherback turtles; Baird’s beaked whales (nb not in the Atlantic); and at 920 meters, the deepest recorded sperm whale dive. It’s pitch dark: you have reached the level that sunlight never penetrates. You are in the Midnight Zone.

Sperm whale dive depth (Neal)

DEEP OCEAN DWELLERS

In black depths below 1000 meters, creatures have adpated to create their own light sources – so-called bioluminescence. This is the realm of the self-lit anglerfish, the blobfish and the goblin shark. It’s the Attenborough world of deep sea exploration. The geology is changing: there are hypervents, volcanic rocks, heavy metals. Below are the deep ocean-floor trenches. Yet there are still recognisable species down here, diving astonishingly deep to 1800 meters to feed – not least the narwhal which makes this trip several times a day to feed.

We need to quicken up the descent now – we have to get down nearly twice as far as this to reach our destination…

Cuvier's Beaked Whale leap (M.Rosso GIMA - IUCN)

We pass large squid and isopods, the deepest diving shark – the Greenland, the 10 meter-long 700 kilo colossal squid – yet amazingly there are marine mammals yet to be encountered: at 2400 meters we drift past a huge elephant seal. There are evil-looking creatures down here with names to match – devilfish, viperfish, black swallowers that can eat a larger fish whole, vampire squid and zombie worms. 

At 3000 feet, we finally end our quest. We have reached the depth to which the world’s deepest diving mammal has been recorded: the Cuvier’s beaked whale Ziphius cavirostris


Cuvier's Beaked Whale (NOAA Fisheries)

Cuvier’s beaked whales, or “goose-beaked whales,” are not rare. For a start, unlike many beaked whale species, they inhabit most oceans and seas in the world and have the most extensive range. Unsurprisingly therefore, they are one of the most often sighted beaked whale species and one of the best studied. 

Cuvier's Beaked Whale Bahamas (BMMRO / Charlotte Dunn)

FIN FACT

You may be wondering about the pressure exerted on a creature at a depth of 3000 meters. The answer is, an astounding 300 atm (atmospheres), enough to crush all but the hardiest and best adapted of species. The question how these whales manage to survive at such a depth is one for the future…

The Cuvier’s is one of the 3 beaked whale species found in Bahamas waters. Like the rarer Blainville’s and Gervais’s beaked whales, the Cuvier’s is the subject of ongoing research by the BAHAMAS MARINE MAMMAL RESEARCH ORGANISATION BMMRO

Cuvier's Beaked Whale leap (BW - Getty - Times)

The research into marine mammal populations in the Bahamas and far beyond is focussed on the massive increase in single and mass strandings, including recently in a remote area of Scotland (Hebrides) where more than 40 Cuvier’s were washed ashore.

One significant area of research examines the effect on marine mammals of man-made noise. There is plenty of it in the world’s oceans caused by noise pollution in and around shipping channels that traverse marine mammal migration, feeding and breeding grounds; naval surface and submarine exercises; seismic surveys, sonar waves and undersea resource investigations. The evidence of sound / acoustic damage as an additional hazard for marine mammals is starting to look very clear.

Cuvier's Beaked Whale Bahamas (BMMRO / Charlotte Dunn)

DEEP WATER INFOGRAPHIC

Do not miss this wonderful work by Neal Agarwal. This article is based around it and includes facts and images derived from his incredibly complex structure that has resulted in a remarkably simple resource for layman and ocean-lover alike (I realise these categories may overlap). To see the entire masterpiece, double click of the box below – “it will be worth it”.

CREDITS: Neal Agarwal; BMMRO / Charlotte Dunn; M.Rosso GIMA – IUCN; NOAA Fisheries; BW – Getty – Times; Pierangelo Pirak / BBC Earth (depth infographic), general sources – BMMRO, IUCN, NOAA, WDC

As ever, the Bahamas Philatelic Bureau has produced a wonderful stamp special issue

BAHAMAS MARINE MAMMAL RESEARCH: 20/20 VISIONS


Sperm Whale Calf, Abaco Bahamas (BMMRO)

Neonate Sperm Whale Calf, Abaco Bahamas

BAHAMAS MARINE MAMMAL RESEARCH: 20/20 VISIONS

Change is in the air. And in the sea. Above, you will notice the brand new logo of the Bahamas Marine Mammal Research Organisation BMMRO based in Sandy point, Abaco. Several major Bahamas-wide projects are in progress or in preparation, and as we approach 2020, this is the perfect time for some marine mammal news, illustrated with great images from BMMRO research trips.

Bottlenose Dolphins, Abaco Bahamas (BMMRO)

Bottlenose Dolphins

BMMRO’s scientific research over many years is a prime reason why we all have the privilege of seeing the neonate sperm whale calf in the header image. It was photographed with its mother off South Abaco last Spring. Much-appreciated support of the essential research and conservation work of the organisation helps to ensure that the whales, dolphins and manatees in Bahamas waters are watched over, documented in minute detail (even their calls) and protected. The marine mammals of the Bahamas have a promising future looking ahead to 2020, and well beyond.

Blainville's Beaked Whale, Abaco Bahamas (BMMRO)

Blainville’s Beaked Whale and young calf

Humpback Whale, Bahamas (BMMRO)

Humpback Whale

ATLANTIC SPOTTED DOLPHINS

WEST INDIAN MANATEES – GINA and RANDY

West Indian Manatee, Bahamas - Gina (BMMRO)  West Indian Manatee, Bahamas - Randy (BMMRO)

All photographs and video footage: BMMRO

Sperm Whale tailing, Abaco Bahamas (BMMRO)

Sperm Whale Tailing, Bahamas

SEAL: THE REAL DEAL


Harbour Seal, Gairloch Scotland (Keith Salvesen / Rolling Harbour)

As Abaco starts to rebuild from the unimagined severity of its destruction, it’s not a great moment for discursive writing about the astonishing richness of wildlife there, both above and below the sea. So here’s a photo of a Harbour Seal that I took this afternoon. If it gives you something to smile about, I’d be very glad. RH