Monitoring the Mexican Forests of the Sea along the Baja California Peninsula

by: Carolina Olguin Jacobson

Photo credit Eduardo Sorensen

Monitoring divers: Anahí Bermudez, Carolina Jacobson, Elba López, Esmeralda Albañez, Jeremie Bauer, Jessica García, Mohamed Sedarat, Nur Arafeh.

eDNA divers: Adrián Munguía and Rosie Poirier.

Underwater professional photographers: Eduardo Sorensen and Jennifer Adler.

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On August 13th, 2023, I was at La Paz port ready to embark on an incredible adventure to monitor the kelp forests along the Mexican Pacific along with other 7 scientists, 2 women community divers from Isla Natividad and 2 underwater professional photographers. Mexico’s kelp forests are distributed for over 1000 kms of coastline and islands along the Baja California Peninsula, and we were going to visit most of them! This was going to be the trip of the year. Everyone was excited, eager to get on the boat, pick a bunk bed and prepare their dive gear.

MasKelp expedition team 2023. Left to right, top to bottom. Eduardo Sorensen, Adrián Muguia, Rosie Poirier, Jeremie Bauer, Mo Sedarat, Esmeralda Albañez, Jenny Adler, Nur Arafeh, Anahi Bermudez, Jess García, Elba López, Adam Hussain, Carolina Jacobson.

We sailed all night, around the tip of Baja California Sur arriving at Cabo San Lucas early in the morning to fill the boat’s fuel tank. We had two more days of sailing before reaching our first site In Isla Asuncion, the southernmost kelp forests. During these two days, our emotions to dive and explore Mexico’s kelp forests grew day by day, we prepared all our equipment, assigned specific tasks to each member of the monitoring team and reviewed the dive plan. We had two teams (North and South team), with 4 members on each team. Each person was responsible for either counting fish, invertebrates, algae or commercially important species, such as abalone or red sea urchins. Along with the monitoring teams, two scientists were sampling environmental DNA (eDNA) from the water which can improve our capacity to detect species. We would be monitoring 39 sites, doing 6 transects on each site, spanning from Bahia Asuncion, in the south to Ensenada, in the north. The photographers were also preparing their lights, cameras and lenses.

On the morning of August 17th, we finally did our first dive. The dive site was beautiful, with lots of sea lions on the surface, spectacular visibility (10m), and calm water although unusually hot (~22°C). The kelp forests in this site used to be dominated by giant kelp (Macrocystis pyrifera) before the 2014-2016 marine heatwave, but now it has transitioned into a southern sea palm (Eisenia arborea) forest. Giant kelp forests can form underwater forests that are over 30 meteres tall, while palm kelp only grows a couple of meters.  We deployed our three transects and started the monitoring. Once we were back on the boat full of excitement from the dive, the captain broke the bad news, hurricane Hilary had changed direction and it was moving in our direction, which meant we needed to leave the area and sail to a safe port (the closest one was Ensenada, ~800km) until the storm passed. Ironically, we were studying the effects of climate change on kelp forests, and now we were threatened by climate change ourselves! Extreme events like Hilary are becoming more common in Baja California and other parts of the world due to climate change!

Hurricane Hilary was not a normal hurricane, it intensified very quickly reaching category 4 with winds of 230km/h. It brought a lot of rain to the Baja California peninsula and the southwestern USA. A storm like this hasn’t occurred in the area in 80 years.

Satellite image of hurricane Hilary in the Mexican Pacific, Saturday August 19, 2023. WindyApp.

After 5 long days of waiting, the storm was not a threat anymore, so we embarked again and re-started our monitoring. We had to re-schedule the sites and dives since we lost many days due to the hurricane. Even with the delay, the whole team was still very enthusiastic, and we managed to successfully monitor 15 sites in Baja California, with the help and support of the fishing cooperative Ensenada, and the photographers captured incredible shots. We finished the North part of the expedition on August 29th. We saw devastated kelp forests by sea urchins, but also signs of recovery with some thriving kelp forests!

Then, one month later a smaller team of three brave divers committed to the task of finishing the South part of the expedition, only this time by land. We packed our diving gear, 13 tanks, and an air compressor in a truck and drove all the way to Bahia Asuncion where we continued the monitoring where Hilary forced us to stop. We had the support of many fishing cooperatives: California de San Ignacio, Emancipación, Bahía Tortugas, Buzos y Pescadores, La Purísima and Pescadores Nacionales de Abulón. This part of the expedition had the most beautiful giant kelp forest I have ever seen, tall and healthy even after the hurricane, and in some places with over 20 meters visibility! The ecosystems in this part of the Peninsula are very well managed and are thriving. We dove 14 sites, normally doing 3-4 dives every day, followed by filling up the tanks, meal preparation, and entering the collected data of the day. It was a lot of work but the reward of seeing those kelp forests was totally worth it. After 15 days, we officially finished the 2023 MasKelp expedition.

Thank you all who made this expedition an amazing experience and an adventure I will remember for the rest of my life. Thank you to all our partners that made it possible: Stanford, UABC, COBI, FEDECOOP, and everyone who was involved!