The marlin run in Mexico’s Baja California Sur is an extraordinary marine migration event that attracts marine enthusiasts, photographers, snorkellers and divers every year. Silke Schimpf has the story.
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The marlin run in Mexico’s Baja California is an extraordinary marine migration event that attracts marine enthusiasts, photographers, snorkellers and divers every year. Silke Schimpf has the story.
Between October and January, the waters off the southern Baja California peninsula teem with vast schools of sardines and mackerel, which are actively hunted by migrating marlin, in some years dorado (mahi-mahi), and other apex predators such as blue and mako sharks. Bryde’s whales also join the feast, while sea lions playfully dive, creating one of the ocean’s most impressive spectacles. This is an awe-inspiring experience for wildlife watchers. Sea conditions permitting, it offers potential encounters with dynamic marine ecosystems, from shimmering bait balls to intense predator-prey interactions.
This guide aims to provide insight for those planning to photograph, snorkel or freedive the marlin run in Mexico, along with scientific details about the species and specific guidelines for safe, responsible interaction with the marine environment.
After a 3.5-hour bus ride from La Paz through the desert and morning mist, visitors arrive at Puerto San Carlos in Magdalena Bay. A grey whale skeleton and a brightly coloured sign greet them at the entrance to the village. Puerto San Carlos is the best and only place for the marlin run. The key to success is the time of year you go (between October and January is best) and the operator and the vessel you choose. It all depends on how well the crew reads the sea, the different phases of the moon and the fish activity on the specific day.
Our choice was an operation of passenger-friendly, converted, single-engine fishing boats run by a pair of brothers who bravely and fearlessly go up to 60km offshore. In search of marlin, bait balls and the right water and temperature conditions, we travelled up to 200km a day on these boats.
Do not get seasick
Blue water temperatures of 19 to 23°C and frigate birds are good indicators of finding possible wildlife action. But even on the journey through Magdalena Bay, there are surprises. During the two-hour ride across the shallow waters of the bay, from the launch site to the edge of the Pacific, lots of birds can be seen, including pelicans, cormorants, terns, shearwaters and frigates. Along the way, there are many pleasant things to see and photograph, including bottlenose dolphins and, in season, grey whales and sometimes even humpback whales. Outside the bay, everything from pilot whales to sperm whales and sea lions is possible, and it never gets boring—ever!
On our seven-day trip, we were lucky enough to encounter mola-mola (the very patient and playful sunfish), common dolphins and Bryde’s whales. We also saw green sea turtles almost everywhere. At this time of year, the sand was still warm and the perfect habitat for laying clusters of eggs in deep holes dug by the turtles on the nearby beaches.
The diving pelicans we saw seemed like powerful, mechanical birds with a strong will to feed. Fearlessly, with open jaws, they plunged into the water from the air. Though hampered by physics and their open throats, they were still successful hunters of sardines and mackerel.
Bait balls in sight
Here is another tip: There are two types of bait balls that can develop in opposite ways—the static bait ball and the dynamic bait ball.
Static bait ball. The static bait ball is a defensive formation observed in certain species of fish, such as sardines, characterised by a dense, spherical aggregation of individual fish. This phenomenon occurs in response to predation, where fish instinctively cluster together to reduce individual risk, confuse predators and enhance collective survival.
When predators such as dolphins or larger fish such as marlin approach a bait ball, they induce a dynamic shift in the formation. The shape of the bait ball becomes less spherical as fish attempt to evade capture. This leads to a loss of spatial dimension for the school, effectively reducing its manoeuvrability. The fish cannot escape the constraints of the aquatic environment, which limits their ability to disperse in three-dimensional space. As predators close in, some fish may be forced into a tighter cluster, further compromising their escape routes.
This interaction highlights the delicate balance between the benefits of collective defence and the vulnerabilities inherent in such formations. While bait balls can deter predators by creating confusion and density, increasing predator pressure forces fish into a more constrained and less effective defensive posture, ultimately increasing the vulnerability of individuals within the school.
Dynamic bait ball
A dynamic bait ball refers to a more fluid and adaptable formation of fish (such as sardines) that continually changes shape and density in response to predator movements. Unlike a static bait ball, which maintains a consistent structure, a dynamic bait ball can rapidly shift its orientation and compress or expand depending on the threat level.
This adaptability allows fish to optimise their escape routes and reduce the risk of being targeted. As predators attack, the fish can quickly reorganise, creating temporary gaps and then filling them as needed, increasing their chances of survival in an ever-changing environment.
Now, if you have a static bait ball, you may just win an opportunity to see action, as each predator and the constraint of the water surface pushes against the bait ball of fish trying to avoid being eaten. Dolphins, whales and the king of them all, the striped marlin, will move in and take their share of the prey right in front of your eyes. This is when the skipper must drop you off in the right direction of the sun. Otherwise, all you will see is glare.
The dynamic bait ball is much more difficult to find and observe but a thousand times more exciting! You need to know the game, get ready on the boat and jump off while the boat is still moving (avoid the propellor!). Once the whitewater has cleared, you need to get your bearings and hustle with fast finning! You will never beat the fastest fish, but you might just catch a glimpse of them. Marlins can reach speeds of up to 50mph (80kph) in the water, chasing the fish until they are exhausted, and then the feast begins.
Photography tips
Remember that a strobe may not be the perfect buddy when swimming fast. In addition, as the fish are being eaten and killed, there will be lots of particles in the water, so a strobe will highlight the backscatter in your images. Also, as the action will be at the surface, there will be enough ambient light to get good shots.
One more thing: Try to avoid becoming part of the bait ball! You might end up with a totally different picture. This is easier said than done. Sardines have small brains, yet they will quickly understand that you are not a threat but possibly a safe haven. So, stay close but never too close for comfort.
There may be several marlins striking a bait ball. To communicate with each other, they will approach with their sails down. When they raise their sails and change colour from pale to blue stripes, an attack is imminent. This is done to avoid injury to one another, but it is important to understand this signal to avoid being speared by the “panga”, as the Mexicans call the marlin’s sword.
Not only are the marlins fierce predators, but dorados (mahi-mahi) take no prisoners either. They move fast and change colour when they are in attack mode. There were a few snorkellers last year who “lost their teeth” when encountering feeding mahi-mahi.
It is indeed an adrenaline rush. If you are lucky, the action can last a good few minutes, and if you are extra lucky, half an hour. But often, the dynamic bait balls last only seconds. So, you need to be fit enough to get back on the boat for another chance to drop in again—many, many times per day.
It is usually around 2 or 3 p.m. when it is time to head back to port. It is a three-hour journey against the pounding waves—and in a hard fibreglass boat, it is not very pleasant. Once back, guests shower, eat, download images and then retire (in most cases). Good thing the food in Mexico is excellent, and the beer is great! It is a tough business, this adventure, for equipment, people and fish alike.
A seasonal spectacle
Fed by seasonal currents, the nutrient-rich waters of the Baja California peninsula create an ideal feeding ground that attracts migrating marine life. Water temperatures between 18 and 22°C increase the chances of encountering sardines. Visibility averages 10 to 15m.
From late fall to early winter, cooler water temperatures and changes in ocean currents signal the sardines to begin their migration, triggering the arrival of a rich array of predators. The convergence of species transforms these waters into a spectacular underwater arena, often marked by bait balls—dense, spherical shoals of sardines swarmed by many marlins and, in some years, dorados, sea lions and even whales (mainly Bryde’s whales, but humpbacks may also be seen).
Scientific highlight: Bait ball formation is a defence mechanism used by sardines that tightly school together when threatened, minimising the risk of individual predation. However, this behaviour inadvertently attracts larger predators.
Preparing for the adventure
The marlin run offers thrilling photographic opportunities, from marlins and dorados diving into bait balls to the synchronised motion of sardines and sea lions. However, respect for the environment is crucial. The goal is to observe without disrupting natural behaviour.
What to expect and how to act
Marine encounters. Expect intense, close-range interactions with various predators. Sardine bait balls draw multiple species, providing unique photo opportunities and mesmerising scenes of cooperative hunting.
Movement in the water. For the best experience and minimal impact, avoid splashing or making sudden movements that can disrupt the predators and prey. Gentle swimming helps you to blend in with the surroundings, allowing you to observe without disturbing marine life.
Photographic moments. Some of the most sought-after shots include:
- Bait ball formations: Capture the dense, swirling formation of sardines.
- Marlins on the hunt: Look for marlins darting through bait balls, often using their bills to spear prey.
- Sea lion interactions: Playful sea lions weave in and out of bait balls, presenting opportunities for dynamic close-up shots.
- Whale sightings: Occasionally, Bryde’s and humpback whales make an appearance, potentially adding a dramatic scale to your photos.
Ethical snorkelling and diving. Keep a respectful distance from all wildlife, especially larger species such as marlins and whales. Avoid chasing or cornering animals, as this can disrupt natural feeding behaviours and cause stress. Observers should limit their interactions and avoid touching or trying to “herd” the sardines into specific formations.
Scientific highlight. Research on marlin and other pelagic fish during the marlin run emphasises the importance of non-intrusive observation methods to prevent disrupting essential feeding and migratory behaviours.
Capturing the magic
The marlin run is a rare and stunning natural phenomenon that allows participants to witness the intricate dynamics of a marine ecosystem in action. Snorkellers and photographers should prepare with a deep respect for the marine environment and aim to capture the event responsibly. With each dive, they will be privileged to observe some of nature’s most impressive creatures and the complex interactions that sustain them.
The marlin run with the experts
For interested freedivers or snorkellers, Expert-Tours offers an exclusive 10-day package combining mako and blue sharks, whale sharks and orcas, as well as sea lions and marlins at: expert-tours.de.
Or you can request just the hardcore marlin run as a 10-day package in Magdalena Bay. For this special package, one must contact Rainer Schimpf directly at: info@expert-tours.com.
Silke and Rainer Schimpf have extensive experience as guides, skippers and citizen scientists and can read the sea and connect the dots out in the ocean to guarantee you the best possible experience and sightings. ■
Expedition leaders and guides Silke and Rainer Schimpf run Expert-Tours in South Africa. For more information, please visit: expert-tours.de.
