Cetacean sanctuary

Mexico’s Baja peninsula is a hotspot for whales and dolphins. Here, scientists have devoted their lives to studying the large number and diversity of cetaceans that visit the region.

Words and photographs by Henley Spiers

Testosterone courses through the air as three-tonne leviathans rise from the depths of the ocean. We are tracking a competitive group of male humpback whales in Mexico’s Sea of Cortez. They are vying for the opportunity to mate with a lone female and the selection process is a brutal test of physical stamina. The whales race in pursuit of the female, swimming at speed whilst battling each other with bruising body blows and swipes of barnacle-encrusted pectoral fins. The effort can be heard in their breathing, transformed from peaceful blows to an intense chugging. The colossal power and size of these 14-metre-long animals sends my heart-rate racing. A dozen males are fighting for supremacy and there can be only one victor. When an individual falls out of the race, he pounds the water in fury, oversized pectoral fins and robust peduncle used to whip up a bath of foamy water. All around us we spot the tell-tale blows of whales. They are here in huge numbers, brought together to raise their calves and procreate the next generation. These ocean giants can lift their entire bodies out of the water. It’s a behaviour taught from the earliest ages, and we watch mothers demonstrate it to their young before the calf attempts to replicate the skill with the clumsiness of a toddler. The breaches are believed to be primarily social behaviour, a form of communication between whales, but it also gets rid of parasites and dead skin.

I am here with Dr. Esther Jiménez López and Dr. Hiram Rosales Nanduca, Mexican professors at the Autonomous University of Baja California Sur, and the scientists behind the Marine Megafauna & Fisheries programme (MMAPE). They have devoted their lives to the study and conservation of cetaceans, working in one of the richest regions in the world for marine mammals. Of the 90 recognised species of cetacean, 38 can be found in Mexico, and of those 32 can be found in the Gulf of California. By operating from the Baja California peninsula, Esther and Hiram have the extraordinary possibility of accessing 35% of all the world’s cetacean species. The reality, however, is more nuanced. As ever when dealing with ocean giants, finding and studying them is a very challenging proposition.

Aimed at unveiling the mysteries of the humpback whales, this is a team expedition. The Oceanographic & Arksen storytelling grant will directly fund the mission logistics, while Dr. Olaf Meynecke, manager of the whales and climate program at Griffith University, has come all the way from Australia, equipped with two Customised Animal Trackings Solutions (CATS) tags. We are united during high season for the migratory humpback whales, most of which have travelled thousands of miles from Alaska and Canada. The competitive group of humpback whales is too preoccupied to be concerned when our panga – the fibreglass style of boat commonly used by Mexican fishermen – joins the race. Hiram manoeuvres with the expertise gained from 20 years of cetacean fieldwork, anticipating the animals’ movements with uncanny skill. Olaf and Esther stay ready at the bow, while a telescopic pole hangs over the ledge with the CATS tag ready for deployment. These tags are non-invasive and use suction cups to attach to the whale for a short period of time before releasing through a galvanic reaction to seawater.

The signature humped back lifts out of the ocean directly alongside us; our boat is dwarfed in comparison. The blowhole opens and a rainbow forms as we are christened with a fine spray of water. It is only with this level of intimacy that Olaf can reach over and drop the tag onto the whale before it disappears back underwater. After numerous failed attempts, the team erupts in joyful relief as we bag our first tagged animal. Esther then aims a crossbow at the whale and fires a specialised arrow to collect a small but highly informative biopsy sample. It is no more than a mosquito bite for the humpback, but this small sample will reveal a catalogue of information, including the whale’s molecular ecology, paternity analysis, trophic level, testosterone and reproductive hormones, stress hormones, the presence of microplastics and heavy metals, and even its estimated age. Meanwhile, the CATS tag will precisely map the whale’s movements in three dimensions, as well as capture its sounds. The addition of a camera will yield even more insight into the hidden life of whales. This marks the first time these special tags have been deployed on humpback whales in the Gulf of California.

‘Great whales’ is the moniker accorded to the largest of the whales, and around the Baja peninsula 6 out of the 12 global species of oceanic behemoths can be found. Grey whales are one of these and, just like humpbacks, they visit Mexico to give birth and raise their calves. Grey whales feed on crustaceans in the seabed and are able to venture safely into far shallower water than most other whales. Travelling 12,000 miles down the Pacific Coast from Alaska, grey whales had long found a safe haven in the shallow lagoons of Baja California Sur’s western coastline. These sheltered bays offer the perfect environment for the animals to give birth and raise their offspring, away from the predators who mar their migration. This was a perfect evolutionary strategy until whalers discovered the lagoons and the easy pickings within. The Eastern Pacific’s grey whale population was almost rendered extinct by the whaling industry. It is important to remember that not so long ago whales were predominantly seen as a commodity.

We lit our streets and homes thanks to their blubber and the demand for their oil was insatiable. It was not until 1986 that a moratorium on whaling was agreed by a majority of the international community. Mexico had already recognised the importance of protecting cetaceans when, in 1972, it created the world’s first Marine Protected Area specifically for whales. With a nascent tourism industry beginning in the area, this legislation was aimed at safeguarding the lagoons and grey whales on the Pacific seaboard. Today, the grey whale population has recovered, and the most recent count estimates their numbers between 17,400 and 21,300.

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Issue 37
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This feature appears in ISSUE 37: WILD ALASKA of Oceanographic Magazine

Issue 37
Supported by WEBSITE_sponsorlogos_arksen
Supported by WEBSITE_sponsorlogos_arksen

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