Humpback whale field research diary - Part 2

Our Storyteller in Residence, wildlife photographer, writer, and expedition leader Henley Spiers, is currently in Mexico to research his next SiR story on the whale sanctuary of Baja California Sur. Here, he shares part two of his personal field diary entry he wrote while tagging humpback whales.

Words and photographs by Henley Spiers

Below you can read an hour-by-hour field diary entry Henley wrote about his humpback whale tagging mission in the Sea of Cortez off Baja California Sur in Mexico. “The SiR grant funds were instrumental in ensuring this research took place as we were able to facilitate logistics of boats and captains and fuel in a way which their own research budget could not meet,” says Henley.

Day 3

5:00 Wake and find batteries haven’t fully charged due to a power-cut and weak electrical current – this is problematic especially for the drone where I was already feeling squeezed for time with only 3 batteries. Eat breakfast in the dark as a purring cat sits on my lap and tries to steal it.

6:00 Drive to the bay and our boat.

6:20 We are on the water before sunrise but it’s overcast so magic hour light isn’t as spectacular as hoped. We find whales within minutes.

7:20 Find humpback whale mother and calf close to the coastline. These waters are a haven for calving, a time when the young humpback whale will guzzle up to 200l of milk a day.

8:30 For the last hour we have tried to slowly habituate the mother and calf to the presence of our boat to an allow an intimate approach necessary to place a tag. We make one last attempt and nearly pull it off, but not quite. We decide to move on as the circumstances are not quite right.

9:30 We listen to whale calls on the hydrophone and eat fruits.

9:50 We find a competitive group of males in pursuit of a single female. This is both very exciting to witness and offers the best opportunity for tagging as they will allow for a close approach.

10:40 Bag my first breaching shot! Breaching is primarily a social behaviour but it also aids in the removal of parasites and old skin. Seabirds quickly fly to the flattened water after a a breach and peck up morsels of food.

11:00 We get a tag on a male! This is the first time a CATs (customised animal tracking solutions) tag has been deployed in this area and the boat is buzzing with excitement. 

The next step is retrieving the tag, worth several thousands of dollars… it will release in about 2 hours but it could be more or less… once turned, the tag will provide a massive dataset including salinity levels, depth, gyroscope, hydrophone, compass direction. Olaf has also fitted a GoPro as additional bonus.

11:20 Start trying to take tissue sample from the tagged male with a crossbow and floating arrow system.

11:35 Successfully deploy arrow onto whale with tag. The sample is a couple of centimetres deep and a few millimetres wide, the impact will be barely perceptible for the animal. This biopsy sample will be analysed to provide information on molecular ecology, paternity, trophic level (feeding habits), testosterone and reproductive hormones, stress hormones, micro plastics, heavy metals, and there is even a technique to age the animal.

12:35 Super slow for the last hour and no sign of the tag releasing. We discover Esther only needs 2-3 hours sleep a night.

14:13 The tag is up at the surface, we know as we can hear clicking from the tag on a vhf radar. Now we follow the clicks in order to find it. The sea is glassy and overcast – perfect conditions for searching.

14:20 Good news as we find tag! Bad news: One of the four suction cups has been lost. Nothing is easy when it comes to operating with technology in the ocean, something I know well from photography and now realise also applies to marine research.

16:00 Start heading home only to see breaching humpback and go investigate – there are so many whales here at this time, it is clear evidence of the importance of this area to them and the need to protect it.

17:30 Back on shore.

17:45 Eat at fishing camp.

18:05 Leave beach.

18:30 Download data, photos, videos. Review and charge up batteries.

21:30 Sleep.

Day 4

5:00 Snooze alarm.

5:10 Wake up. Realise there was a problem with the tag data downloading, and drone batteries not charging well. This limits our capabilities before the day has even begun.

6:00 Leave cabin.

6:30 On water, overcast, no magic hour light.

7:20 Spot three grey whale juveniles – an unusual sighting here.

7:30 Rain starts – this makes drone flying a problem.

7:45 Spot Munk’s devil rays jumping – they are starting to migrate en masse into the Sea of Cortez.

8:30 Find the competitive group of males. Get restless and fly my drone in the rain…

9:38 Get tag on! Everyone feels good… Although the tags are the highlight, the team has a lengthy list of tasks to complete. They need photos from the boat of fins for their ID database, drone photos from a set height to measure length, and biopsy samples. These come on top of finding the animals and skilfully driving the boat in their vicinity. It’s a full-on job and everyone mucks in.

10:00 Still buzzing from close proximity to the competitive males, and with the overconfidence of several successful drone flights from the panga… I swiftly crash my drone on take-off as it hits the vhf antenna… miraculously, it falls back into the boat. Aside from replacing two propellers, it seems to have survived the experience… I was very lucky, but it will take a while for my heart rate to drop.

10:30: Spot a Cuvier’s beaked whale, a very rare animal. The dictionary definition of excitement should be changed to: three cetacean scientists see a beaked whale.

13:10 We get another tag on! The team is on a roll today.

13:20 Rain finally stops and wind drops too. The sea is oily and flat. We are riding with 15 humpback whales, life is good.

13:45 We have lost the whales and good vibes are replaced by concern as to the whereabouts of the tag and how long it will remain before detaching.

15:00 The beeps of the antenna vhf receiver sound like life support – a reassuring sign of life for the tag which is now somewhere on the sea surface.

15:20 Find the tag.

15:30 Debate whether the redeploy the tag… decide it would not be wise as the collection would likely have to take place in the dark or the next day (by which time it could have drifted a great distance).

17:30 Back on the beach and time for dinner.

18:30 Recharge, review, sleep and repeat.

Day 5

5:00 Snooze alarm.

5:10 Five more minutes…

5:15 Wake. Fumble in darkness as we discover there has been another power cut. The unreliability of electricity has proven to be a serious and unexpected challenge.

6:30 On the water. Weather is overcast and after a few calmer days the wind is set to blow harder.

6:55 Find a mum and calf. Calf is maybe 3 weeks old. They darken with age and develop a less floppy dorsal fin.

8:00 See whales but we are looking for the ‘right’ whales – those we can safely approach closely to tag. If only we could locate that group of competitive males… but today the waves are up and the sun is out, difficult conditions to spot life on the ocean. After a really great day at sea, a strange psychology takes hold where my brain thinks: “That was good, it will be good to do it again tomorrow.” But nature and weather operate on a different rhythm, and yesterday is no guarantee of tomorrow.

8:30 Things are slow, time for a breakfast burrito. Esther and Hiram’s consumption of habanero sauce is prodigious. We are already onto our second bottle in just five days… back home the same bottle would probably last me a few years.

8:50 See whales but not a big group… attempt to photograph them underwater by hanging my camera over the side of the boat. Results are middling. It is forbidden to enter the water with baleen whales in Mexico but under the scientific permit I could have done so. Nevertheless, achieving our scientific targets has superseded my barely restrained desire to get an underwater perspective.

9:30 Find three males and track them… but never get a good opening to approach and tag.

12:30 It’s not been our day… encounters and the sea state weren’t favourable. As the wind continues to pick up, we head back for shore. Mission over… for now at least, I will return in spring to continue documenting the work of these Mexican cetacean scientists.


For more Despatches, images and more, follow our 2023 Storyteller in Residence’s journey here or over on Instagram

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