How Cruise Ships are Harming Mexico’s Whale Sharks

The largest shark species is also the gentlest. These massive fish are peaceful, spending their lives gliding through the oceans calmly. They support their huge bodies by consuming copious amounts of plankton and can grow to 20 tons. They are especially well known off Mexico’s La Paz coast, where they are becoming less common due to cruise ship tourism.

La Paz has grown immensely popular in recent years, attracting tourists to its tropical beaches and beautiful waters. Commercial cruise lines have capitalized on this interest, adjusting their itineraries to include the area. Sadly, this increased activity has harmed the marine ecosystem of the Bay of La Paz, dwindling local whale shark populations.

This slideshow highlights how whale sharks contribute to the region's ecology, why they prefer La Paz as a habitat, and how the species continues to be threatened. We also cover how conservationists and researchers are taking steps to protect these huge, endangered sharks.

• Whale sharks are the largest sharks in the world, weighing up to 20 tons
• Despite their size, they are harmless filter feeders that consume plankton and small sea creatures like krill and squid
• Whale sharks are in decline due to human activities, including tourism in areas like Mexico

• La Paz, Mexico, offers a quieter tourist destination compared to nearby Los Cabos
• Its location in the Bay of Cortez supports over 900 species of fish
• Whale sharks are among the rich marine life found in the Sea of Cortez

• Tourism growth in La Paz is endangering its marine ecosystem
• Aquamayan Adventure plans to expand cruise traffic with a goal of 150,000 passengers annually
• This number is nearly half the local population and raises major environmental concerns

• In 2018, the Bay of La Paz was declared a whale shark refuge
• Scientists found that 66% of juvenile whale sharks had boat injuries
• Conservation efforts now aim to minimize tourism impact

• Whale sharks regulate plankton and algae populations, preventing ecosystem imbalances
• They provide shelter for smaller fish, creating mobile habitats
• Without whale sharks, marine environments can become oxygen-depleted

• In December 2020, cruise ships idled in La Paz, releasing scrubber washwater
• This toxic discharge can deform marine life at very low concentrations
• Whale shark sightings plummeted by April 2021

• One cruise ship emits as much toxic gas as up to 30,000 cars
• Polluted water remained trapped in La Paz Bay due to protective dunes
• The polluted water and noise likely disturbed whale shark feeding patterns

• Environmentalists are calling for the cancellation of cruise terminal plans
• They aim to prevent further harm to the whale shark habitat
• Public support is growing through awareness and advocacy

• In 2025, researchers began using drones to track whale shark movements
• Drones help monitor the impacts of tourism and pollution
• The project was funded by crowdsourcing efforts