Big Animals and Where to Find Them: Striped Marlin Encounters in Baja California

The striped marlin (Tetrapturus audax) is a formidable predator that sits near the top of the marine food chain. Don Silcock explains how, as a member of the billfish family, it is distinguished by its spear-like upper jaw, which serves as both a hunting tool and its most-prominent feature

What Is a Striped Marlin?

Easily recognised by their striking appearance, their bodies are dark blue-black on top, which fades to a silvery white underside and are adorned with vertical blue stripes that give them their common name. Fully mature individuals can reach up to four metres in length and weigh as much as 200kg. Those impressive dimensions, combined with their intense resistance when hooked and their acrobatic leaps, make them highly sought after by sport fishers.

They are epipelagic and inhabit the upper 100m of the tropical and subtropical waters in both the Pacific and Indian Oceans, but spend most of their time near the surface, where they hunt schools of sardines, mackerel, and anchovies.

Although they are capable of long-distance travel and can reach speeds of up to 80 km/h, they are not the fastest among marlins. That title belongs to the blue marlin, which can hit speeds of 130 km/h, followed by the sailfish at 110 km/h. The marlin’s speed and agility are attributed to its streamlined, torpedo-shaped body and elongated tail lobes, which extend into undisturbed water beyond the turbulence generated by its movement.

Striped marlins can live up to ten years and reach sexual maturity between one and two years of age. During their summer spawning season, females release batches of eggs every few days, producing an estimated 120 million eggs over the season in a process known as serial spawning.

Where Striped Marlins Are Found

Baja California, Mexico, is widely considered the top destination to observe striped marlins in the wild, with the waters offshore from Magdalena Bay – on the Pacific side of the peninsula – offering some of the very best encounters.

The Baja Peninsula is situated at the convergence of the cold, nutrient-rich California Current and the warmer waters of the Pacific Ocean. This mixing of those water masses creates nutrient upwellings along the continental shelf, producing massive plankton blooms that attract large schools of sardines and mackerel – the striped marlin’s food of choice. Sport fishers have known about all this for many years and have made that area and, to a lesser extent, the waters around Cabo San Lucas, very popular locations for striped marlin game fishing. But in recent years, that phenomenon has become known as the ‘Mexican sardine run’, and each year it attracts many underwater photographers.

The Mexican Sardine Run Explained

The catalyst for the sardine run is the annual spawning of Pacific sardines, which occurs in the deep offshore waters out from Magdalena Bay from mid-October through to late-December. Incredibly prolific breeders, one female sardine can spawn 65,000 eggs at once and up to 200,000 eggs per season.

Little is known what happens to newly hatched sardines except that they don’t stay with their mothers. But as they get older and bigger, they aggregate in large, dense schools near the ocean surface and migrate up the Pacific coast. Those schools are like super-magnets to both birdlife and Californian sea lions, striped marlin and mahi mahi, which treat them like an all-you-can-eat buffet – attacking and eating the sardines till they are all gone!

It’s hard to adequately describe the sheer intensity of those ‘bait balls’ – but nature at its most raw will probably give you a degree of insight! The sardines are in almost constant and synchronised high-speed motion as they dodge and weave to try and avoid the never-ending attacks.

The sea lions tend to hunt as a pack to isolate and restrict the bait ball, or parts of it, before attacking, while the large numbers of mahi mahi charge into the bait ball in an uncoordinated, random, but very aggressive manner.

The striped marlin also seem to coordinate with each other as they closely circle the bait ball and then attack at incredible speed. Compared to the blunt tool of the mahi mahi or the more strategic and energetic sea lions, the marlin are like rapier swords used with amazing precision.

In-Water Encounters with Pelagic Predators

With so much going on at the same time it’s easy to get in between the hunters and the hunters… Those hunters are intently focused on their prey, so getting in the way of a charging mahi mahi will get you whacked as they seem unable or incapable of dodging round you.

The sealions, although much bigger, are more agile and spatially aware and able to avoid you quite easily, albeit at the very last moment…

The striped marlin are in a class of their own and are so fast that you have to rely on them avoiding you, because you are too slow to avoid them. Their long and sharp bill is a lethal weapon in itself, but they seem very protective of it – which saved me on one very close encounter!

Frequently Asked Questions