Welcome to the Dashboard, !

Close dashboard icon
LibreOrganize 0.6.0 - Documentation

Protecting Fish of the Mexican Caribbean

from the June 26, 2024 Bulletin

You’ve focused your research on the Caribbean Sea. What’s the diversity of marine life there? 


I’ve been fortunate to spend a lot of my life underwater on the East Coast of the Yucatán Peninsula in the beautiful Caribbean Sea. I used to dive up to 100 feet deep, but in my current project, we’re only going down about 45 feet. And not far from shore. The coral reef crest occurs about half a mile from the beach, and our team dives in the fore-reef area.


The Mexican Caribbean is home to about 600 or 700 species of fishes; the whole Caribbean Sea is home to maybe ten times that.


Over recent decades, have you witnessed a decline in biodiversity? 


Not so much a loss in terms of extinctions, but a loss of abundance, in frequency of rare species, of body size and of carnivorous creatures at the top of the food chain.

Goliath grouper    Photo: Humberto Bahena. 

Take the Nassau grouper. We used to have thousands. They mated in specific areas, and during the mating season, it was an orgy —  a wall of fish from the sea floor to the surface! But overfishing — not by industrial fishing but small fishermen — has decimated them. Those reproduction areas are empty. The Goliath grouper  — which can grow up to 8 feet long and 800 pounds — is even rarer, I’ve seen only two or three in 30 years of diving.

Fishing isn’t allowed in particular areas and seasons, but the rules are ignored. Unfortunately, our enforcement tools are poor — park rangers are underfunded, understaffed, and underequipped. Because they have no authority to arrest, the laws are toothless. It’s an example of how AMLO’s austerity has undercut good policies.


Climate change is also a problem. Warming kills the coral because the symbiotic algae leave the coral polyps. That weakens them, and they eventually die. The dead coral tends to erode with storms, and the reefs flatten out and degrade over time. The small plants and animals at the bottom of the food chain become scarce, and that contributes to the diminishing populations of larger creatures at the top of the food chain.


Critics of the Mayan Train have said it’s a threat to the region’s biodiversity. As a scientist living and working near the construction, do you also oppose the project?

I do not oppose it. In fact, compared to cars and highways, the electric train can be beneficial — less pollution and roadkill. Inland lakes and waterways contain about 150 species, and some are endemic, meaning they are unique to that areaAbout a dozen are endangered species, including the two blind cavefishes. None are threatened by the train itself.

Mexican Blind Cave Fish 

Cave divers in a cenote near Tulum 

Some divers oppose the Train. They like to dive in the caves found in cenotes — deep sinkholes that have become tourist attractions in the Yucatán — and allege that these could be damaged. In fact, they are a bigger threat because predatory fish from the open area of the cenotes follow them into the dark tunnels and prey on the endemics.

Its been said that AMLO has a poor record on the environment. What do you think of his performance? 


It’s said that AMLO favors oil because he built a new oil refinery. Well, we need oil for an energy transition. AMLO built a refinery — but also the largest solar plants in Latin America. He’s also increased the number of areas protected from development projects.


A new science law got passed calling for ethnobotanical gardens in every state. It emphasizes that traditional knowledge has a place in science, or rather, sciences in plural, because it speaks about a "dialog between knowledges" (diálogo de saberes) and about the human right to science — science for the people.


This is important because “environment” is often defined as nature minus people. But this law recognizes that people who have traditionally lived in harmony with nature should be listened to.


Water shortages have been in the news. Does the new science law help solve that problem?

Water is scarce in the Yucatán and always has been. Much of the soil is limestone, and water dissolves it and passes through it. The Mayans built chultuns, artificial underground reservoirs made waterproof with sascab, a paste made out of the limestone itself.

An ancient Mayan chultun at the Uxmal ruins, Yucatán

More "modern" devices to capture rainwater include the curvatos, perhaps used for over a century. These wooden and, more recently, cement tanks receive rainwater from the roof via pipes and conduits. I have one at home, we use curvato water for the garden.

Mérida, the largest city in the Yucatán, extracts too much water from the aquifer. The water gets salty because seawater flows in as the freshwater layer gets thinner.

What to do? Limit urban development, and establish green belts within the urban areas. Manage rainwater as the Mayans did with their chultuns. Combat pollution from hotels and pig farms.


What has amazed you about marine life? 


Until recently, I didn’t pay enough attention to fish cleaning stations, these places on the coral reef where large fish go to get groomed by a small fish or shrimp. The small cleaners eat the parasites on the big fish — which allows them to swim right inside their mouths and gills! We also found that, contrary to intuition, this amazing interaction occurs more often in impacted reefs than in the more protected areas, perhaps because of a bigger parasite load.

Sea Robin 

My favorite sea creature is the sea robin. It has an armored head and “fingers,” which are free and mobile rays on the pectoral fins. These rays have taste buds, used to search for food in the bottom sand or mud. The fins can spread out like wings. Their purpose is not to glide like flying fish, but to put on a colorful display that distracts predators or attracts mates.

Most of what goes on under the sea is still unexplored — it has so much more to teach us and to amaze us — if we protect it now.