Home > Sailfish & Brief History

One question we often get asked is, what is the purpose of the huge dorsal fin? While diving at close quarters with these bold Sailers (bold because they’re not shy to swim close to free-divers & display intimidating postures with their dorsal fins spread high & wide) we observed that the fin plays an integral part in the awesome feeding behaviour of the Sailfish.

Sails like dolphins & most other schooling pelagics co-operate when feeding. One or two Sails will act as “herders”, making a series of leaps, crashing loudly or slapping horizontally on their sides to round up a school of baitfish into a tight ball while their mates (approx 10-15) surround the bait & pack them into an even tighter ball. The high dorsal fin acts like a cape flashing neon electric blue & purple colours, encircling and mesmerizing the bait to prevent any from dispersing or escaping. This in turn causes the baitfish to panic & pack tighter together. Simultaneously, the Sails move in 1 or 2 at a time into the bait ball swiping & stunning the bait with their sword-like bill. Such good manners & etiquette! Sails would do well in a buffet line…

The teamwork is also amazing to watch and similar to other great predators like wolves and lions.

The bill also plays another function. We believe that Sails actually ‘fence’ with their bills and you can see a picture in our photo gallery above of a Sail with a broken-off bill tip embedded in its jaw. We understand that Sails exhibit aggressive behaviour during courtship/mating & may also be very territorial.

Billfish like most predators burn plenty of energy hunting for food & will eat what’s available & easiest to catch, including the occasional puffer fish or even the dreaded lizard fish you get on your Sabikis.

We believe that each Sail has its own personality and this can be see in the way it takes the bait and fights, from long exuberant tail walks on the surface, to frisky leaps & jumps, to head-jerking on the surface & fighting deep below like a Marlin or big Tuna. Even charging towards the stern or side of the boat!

They also come in different shades and colors dependent on the level of excitement or stress, and even the length, thickness or shape of the bill can vary. We have observed Sails with their bills broken off, either naturally or by souvenir hunters, although we would like to believe that they were just inexperienced anglers grabbing the bill too high up near the tip while leadering the fish in & that simple physics caused the bill to break while it was thrashing violently. We have also captured Sails without their signature high dorsal fins that have been deliberately cut-off (hope it’s not a really sick ploy from anglers trying to pass the Sail off as a Marlin in a fishing competition!). Thankfully, all seem to have survived their ordeal.