“Hold it, hold it!” The sharp orders came from captain Anthony Mendillo on the bridge. “Steady, steady…OK…go NOW!” I rolled off the transom of the “Keen M”, and was surrounded in a swirl of bubbles, in a blue void. They quickly cleared and I looked right into the panicked faces of a couple hundred sardines, trying to avoid a hoard of marauding sailfish that swept by with impressive speed, right behind the tight school of sardines. I got below the school shooting upward at the ball of fish and predators circling against the choppy surface, frigate birds circling above. The sardines then took refuge next to me and this pulled the sailfish in closer as they whacked at the packed school with their bills. They were so close I could see every scale in the skin, and hear as their bill impacted on the hapless sardines. They would spin around to grab the sardine knocked out of the school, before joining again in the chase, another sailfish working on the sardines, with others hanging nearby waiting their turn. I was breathless as I captured this startling predator-prey interaction on my HD video in a Gates housing.

So began the first day of a four day shoot for my TV series “Portraits from the Deep” in Isla Mujeres, Mexico, just about 400 miles west of the Cayman Islands. I had chartered Anthony Mendillo to put me on the fish, and that he did. The sailfish show up in big numbers from January to April and can be found balling schools of sardines out on the shelf. We looked for big aggregations of frigate birds, and sure enough, below would be a school of sardines being worked by anywhere from ten to fifty sailfish. Awesome!

I have encountered only one sailfish in my ten years of diving and fishing in the Cayman Islands. While sailfish migrate past the Cayman Islands, they are not common. The blue marlin is the billfish most encountered, and are found near the deep drop offs and at the 12 Mile Bank all year round. There is not enough bait here to hold the numbers of sailfish seen in Central America or off Florida. There are no rivers in the Cayman Islands, so few terrestrial nutrients reach the waters. Additionally, the insular shelf drops off very sharply, so there is only a narrow shelf for primary productivity of plankton on which the sardines feed. We are in the middle of an area of ocean with very low productivity, an oceanic desert. This why if I want dive with sailfish or fish for them the best places in the Caribbean are Florida, Mexico and Venezuela.

The sailfish is the most common of the ten billfish species, and are distributed world-wide in tropical waters. The average size of the Atlantic sailfish is 40 to 60 pounds they are one of the smaller billfish species. In the Eastern Pacific they grow twice that size reaching 200 pounds. The outstanding characteristic of the species is the enormous dorsal fin which is much higher than the greatest depth of the body. This fin is used to make the sailfish look three times the size it really is and is particularly used when corralling bait schools as I described earlier. When working in tandem with other sailfish in what I describe as cooperative feeding, the sail is raised and used to keep the bait in a tight school which is then easily managed by the predators. In addition they change colour frequently, with dark blue backs, and bronze flanks cut by vivid stripes when excited. They are marvellous animals to paint, which why diving with them is so important, to capture the anatomy, colour and movement and the thrill of the chase.

In the western Atlantic sailfish spawn in spring and summer. The tiny fertilized eggs hatch and grow very rapidly, just as all oceanic fish species do. The sailfish will reach six pounds in six months, and may be 30 pounds in their first year. Tagging has shown sailfish will live as long as 12 years and make large seasonal migrations, though some will linger in good feeding areas for long periods. They eat a variety of oceanic species, such as sardines, anchovies, puffer fish, file fish, flying fish, small tunas and bonitos, jacks and ballyhoo. In turn they have few predators, but the large sharks such as the mako, tiger and bull sharks have preyed upon sailfish, as do large blue marlin and some large toothed cetaceans, like orcas. 

There is little directed commercial fishing for sailfish in the Caribbean, but there is a lot of commercial long line activity in the eastern Pacific. This is unfortunate, particularly in Costa Rica, where the recreational use of sailfish is much more valuable to the local economy as a living fish than the fish as a protein source. Socio-economic studies in Central America have shown the sailfish to be a very valuable sustainable resource in the catch and release fishery. The use of circle hooks in this fishery ensures 99 per cent survival, and so some countries like Guatemala have banned the landing of all sailfish. There is currently an effort in Central America to have a regional approach to the management of the species, particularly as the species migrates extensively along the coasts of the member countries.

My underwater encounters with sailfish and sardines off the coast of Isla Mujeres were some of the most graphic and inspiring I have had in 15 years of diving with billfish all around the world. Underwater photography of these marvellous fish has become more exciting and educational compared to their angling value and provides a unique experience in certain locations.

It is our collective responsibility to conserve all marine creatures and maintain the biodiversity of the planet.

Good diving.

Guy Harvey PhD. www.guyharvey.com