Fish sail or sailboat: what speed does it develop, where does it live?

Wild animals
>>
Fish

The sailfish is the fastest fish in the world, reaching a speed of 100 km/h. The record was recorded at 109 km/h. The fish got its “ship” name because of its huge dorsal fin, which looks like a sail. These fish are generally considered a valuable sport fish, and their meat is often used to make sashimi and sushi in Japan. Although there is little specific information about the relationship between individuals, swallowtails can "flash" their body colors through the activity of their chromatophores and use other visual cues (such as dorsal fin movements) during reproduction.

Origin of the species and description

Photo: Sailboat

The sailfish (Istiophorus platypterus) is a large, open-ocean predator that grows in tropical and subtropical regions virtually throughout the world. Previously, two species of swallowtail were described, but both species are so similar that science increasingly recognizes only Istiophorus platypterus, and the previously recognized species Istiophorus albicans is considered a derivative of the first. Also, at the genetic level, no differences were found between the DNA that would justify division into two species.

Video: Sailboat

The sailfish belongs to the family Istiophoridae, which also includes marlin and spearfish. They are different from swordfish, which have a flattened sword with sharp edges and no pelvic fins. In Russia it is rare, mainly near the Southern Kuril Islands and in the Peter the Great Gulf. Sometimes it enters the Mediterranean Sea through the Suez Canal, and the fish travels further through the Bosphorus Strait to the Black Sea.

Marine biologists speculate that the "sail" (array of dorsal fins) may serve as part of the fish's cooling or heating system. This is due to the network of large numbers of blood vessels found in the sail, as well as the behavior of the fish, which only "raises the sail" in or near surface waters after or before high-speed swims.

Appearance and features

Photo: What a sailboat looks like

Large specimens of the sailfish reach a length of 340 cm and weigh up to 100 kg. Their spindle-shaped body is long, compressed and surprisingly streamlined. Individuals are dark blue above with a mixture of brown, light blue on the sides, and silvery white on the ventral side. This species is easily distinguished from other marine fish by the approximately 20 stripes of light blue dots along their sides. The head bears an elongated mouth and jaws filled with serrated teeth.

The massive first dorsal fin resembles a sail, with 42 to 49 rays, with a much smaller second dorsal fin, with 6-7 rays. The pectoral fins are rigid, long and irregularly shaped with 18-20 rays. Pelvic fins are up to 10 cm long. The size of the scales decreases with age. The swallowtail grows quite quickly, reaching 1.2–1.5 m in length within one year.

Interesting Fact: Sailfish were previously thought to reach a maximum swimming speed of 35 m/s (130 km/h), but studies published in 2015 and 2021 show that sailfish do not exceed speeds between 10–15 m/s.

During the predator-prey interaction, the swallowtail reached a splash speed of 7 m/s (25 km/h) and did not exceed 10 m/s (36 km/h). As a rule, sailboats do not reach a length of more than 3 m and rarely weigh more than 90 kg. The sword-like, elongated mouth, unlike the swordfish, is round in cross section. Gill rays are absent. The sailfish uses its powerful mouth to catch fish by making horizontal strikes or lightly bumping and disorienting individual fish.

Now you know what speed the sailboat develops. Let's see where this amazing fish is found.

Maximum speed

The sailfish is the fastest fish in the world, capable of accelerating up to 109 km/h. This is facilitated not only by a strong muscular body, but also by a special shape of the muzzle. The growths on the upper and lower jaws create turbulence, which reduces water resistance and allows for greater speed. The tail of a sailboat also creates turbulence due to the high frequency and small amplitude of the strokes. It is also worth noting the asymmetry of the tail part of the body relative to the horizontal plane, which also increases the effectiveness of the rear fin.

Where does the sailboat live?

Photo: Sailboat at sea

The sailfish is found in both temperate and tropical waters of the oceans. These fish usually have a tropical distribution and are especially numerous near the equatorial regions of the Atlantic, Pacific and Indian Oceans from 45° to 50° N latitude. in the western part of the North Pacific Ocean and from 35° to 40° N. latitude. in the eastern part of the North Pacific Ocean.

In the western and eastern Indian Ocean, sailfish in the Indo-Pacific range between 45°S and 35°S. respectively. This species is mainly found in coastal areas of these latitudes, but can also be found in the central regions of the oceans.

Interesting fact: Sailfish also live in the Red Sea and migrate through the Suez Canal to the Mediterranean Sea. The Atlantic and Pacific populations have contact only on the coast of South Africa, where they can mix.

The sailfish is an epipelagic marine fish that spends most of its adult life from the surface to depths of up to 200 meters. Although they spend most of their time near the ocean's surface, they sometimes dive into deeper waters where temperatures can reach as low as 8°C, although the fish's preferred water temperature ranges from 25° to 30°C. The swallowtail migrates annually to higher latitudes, and in the fall to the equator. Older individuals usually live in the easternmost regions of the Atlantic and Pacific oceans.

Marlin diet

All species of marlin are classic predators whose diet includes other types of fish, squid and crustaceans. Within the territorial waters of Malaysia, the main diet of marlins consists of anchovies, various types of horse mackerel, flying fish, and squid.

The main diet of sailfish is small fish that live in the upper layers of water, including sardines, anchovies, mackerel and mackerel, as well as crustaceans and cephalopods. Atlantic blue marlin fry prefer to feed on zooplankton, as well as eggs and larvae of various fish species. Adults eat fish and squid. Within coral reefs, blue marlin prey on small coastal fish.

Western Atlantic spearfish hunt in the upper layers of water for fish and cephalopods, while their diet is much more varied. In the southern waters of the Caribbean Sea, their diet includes herring and Mediterranean tarsier. In the western waters of the Atlantic Ocean, the basis of the diet is Atlantic sea bream, snake mackerel and various species of cephalopods.

Representing the northern subtropics and tropics of the Atlantic, spearfish feed primarily on fish and cephalopods. Up to 12 different species of fish were found in the stomachs of caught marlins.

Marlins on the hunt (Marlin)

What does a sailfish eat?

Photo: Sailfish

The sailfish develops great speed, its dorsal fins folded halfway in pursuit of prey. When sailfish attack a school of fish, they completely fold their fins, reaching an attack speed of 110 km/h. As they move closer to their prey, they quickly turn their sharp snout and strike the prey, stunning or killing it. The swallowtail either hunts alone or in small groups. The specific species of sailfish eaten by sailfish depend on the spatiotemporal distribution of their prey populations. Remains of cephalopods and fish jaws found in their stomachs suggest rapid digestion of soft muscle.

Typical products for sailboats are:

mackerel;
sardine;
small pelagic fish;
anchovies;
squid;
rooster fish;
crustaceans;
mackerel;
half-snout;
sea bream;
saberfish;
giant trevally;
cephalopods.

Underwater observations show sailfish flying at full speed into schools of fish, then braking with a sharp bend and killing the fish within range with quick sword strikes, and then devouring them. Often several individuals exhibit team behavior and work together to hunt. They also form feeding communities with other marine predators such as dolphins, sharks, tuna and mackerel.

Interesting fact: Small fanfish larvae feed mainly on copepods, but as they increase in size, the diet very quickly switches to larvae and very small fish only a few millimeters long.

Damage caused by sailfish to prey reduces their swimming speed, with injured fish more likely to be found at the rear of the school than uninjured ones. When a sailfish approaches a school of sardines, the sardines usually turn around and swim in the opposite direction. As a result, the sailfish attack the school of sardines from behind, putting those fish in the rear at risk.

Food and method of hunting

Sailfish hunt small fish like sardines. Typically, their prey gathers in schools and moves as a unit. Thus, small fish try to confuse the predator and not become an easy meal. Hunter fish watch the schools, trying to scare them and get their prey. Sailfish are one of the strongest hunters, they destroy their prey in a matter of seconds. Thanks to their speed and maneuverability, they instantly disappear into the water.

Features of character and lifestyle

Photo: Fast sailfish

Spending most of their time in the upper 10 m of the water column, sailfish very rarely dive to depths of up to 350 m in search of food. They are opportunistic eaters and eat whenever possible. As migratory animals, fish prefer to follow ocean currents with surface seawater whose temperature fluctuates above 28°C.

Interesting fact: Sailfish from the Indo-Pacific region, tagged with pop-up satellite archival tags, have been tracked traveling more than 3,600 km to spawn or forage. Individuals swim in dense schools, structured by size as juveniles, and form small groups as adults. Sometimes sailboats sail alone. This suggests that Indo-Pacific swallowtails feed in groups according to their size.

Sailfish swim away both for long walks and often stay near the coast or near islands. They hunt in groups of up to 70 animals. Only every fifth attack results in successful production. Over time, more and more fish become injured, making them easier to catch.

The fin-sail is usually kept folded while swimming and is raised only when the fish attacks its prey. The raised sail reduces the lateral movement of the head, which probably makes the elongated mouth less noticeable to fish. This strategy allows sailfish to place their mouths close to or even into schools of fish without being seen by prey before striking them.

Social structure and reproduction

Photo: Sailboat in the water

Swallowtails breed all year round. Females extend their dorsal fin to attract potential mates. Males engage in competitive races, competing over females, which end in spawning for the winning male. During the spawning season in the western Pacific, the sailfish, which are over 162 cm in length, migrate from the East China Sea towards southern Australia to spawn. Sailfish off the coast of Mexico appear to be following the 28°C isotherm south.

In the Indian Ocean, there is a high correlation with the distribution of these fish and the months of the northeast monsoon, when the waters reach an ideal temperature above 27° C. Sailfish spawn throughout the year in tropical and subtropical regions of the oceans, while their main spawning season is in the summer at higher latitudes. During this time, these fish can spawn several times. The fertility of females is estimated from 0.8 million to 1.6 million eggs.

Fun Fact: The maximum lifespan of a sailfish is 13 to 15 years, but the average age of specimens caught is 4 to 5 years.

Mature eggs are translucent and have a diameter of about 0.85 mm. Eggs contain a small globule of oil that provides nutrition to the developing embryo. Although the growth rate of larvae is influenced by season, water conditions and food availability, the size of newly hatched larvae usually averages 1.96 mm chord length, increasing to 2.8 mm after 3 days and to 15.2 mm after 18 days. days. The young grow exponentially during the first year, with females tending to grow faster than males and reach sexual maturity more quickly. After the first year, the growth rate decreases.

Unusual body structure and other characteristics

First of all, this is a special gutter, which is located on the back. The sailboat retracts its large main fin into it when moving quickly, and instantly straightens it during sharp turns and other maneuvers. At the same time, the visual size of the individual increases 3 times.

Sometimes you can observe the unfolded fin of a sailfish at rest above the surface of the water.

The jaws also have a unique structure, reminiscent of the jaws of a pipefish. Externally imitating a pike, they have an impressive length and create turbulent flows when moving. Moving even at low speed, the predator easily overcomes the resistance of water.

To accelerate in the water column, the fish mainly uses the tail muscles, while the amplitude of the tail movement has a small range, but a significant frequency. The caudal fin is represented by two narrow stripes that have a steep, almost perpendicular slope in relation to the body. With this principle of tail movement and fin structure, maximum speed is achieved.

The sailfish does not have a swim bladder. This means that the fish has negative buoyancy, meaning it does not have to overcome additional resistance.

So, the factors that allow the sailboat to take first place in speed among fish:

unique body structure;
peculiarity of the jaws and turbulence;
notch for closed dorsal fin;
absence of a swim bladder.

There is an interesting opinion from scientists about the large fin on the back of this fast-moving vessel. It contains a significant number of tiny blood vessels, and swimming at high speeds warms up the fish's blood. Therefore, in order to cool it down, the giant jumps to the surface at full speed, straightening its fin.

The lifespan of fish is short - about 13 years. Breeding takes place in warm waters in August and September. The eggs are small; in just one spawning period, the female is capable of laying up to 100 million eggs, but the young die en masse. Parents do not pay attention to their offspring, so the fry often become food for other predators.

Natural enemies of sailfish

Photo: What a sailboat looks like

The swallowtail is the pinnacle of predation, so predation on free-swimming individuals of the species is very rare. They significantly influence prey populations in the open ocean ecosystem. In addition, fish serve as hosts for various parasites.

Mostly sailboats are attacked:

sharks (Selachii);
killer whales (Orcinus orca);
white shark (C. Charcharias);
people (Homo Sapiens).

It is a commercial fish and is also caught as bycatch in the global tuna fishery. The fish are caught incidentally by commercial fishermen using drift nets, trolling, harpooning and netting. The sailfish are most important as a sport fish. The flesh is dark red and not as good as blue marlin. Sport fishing may pose a potential threat locally, especially since the species is found close to shore and around islands.

The world's highest catch rates of sailfish are found in the eastern Pacific Ocean off Central America, where the species supports multimillion-dollar catch-and-release sport fisheries. In Costa Rica's national longline fishery, many fish species are discarded because the fishery is only allowed to bring in 15% of its catch as sailfish, so the catch is likely underestimated. Recent catch per unit effort (CPUE) data from Central American fisheries has raised concerns.

In the Atlantic Ocean, the species is captured primarily in longline fisheries, as well as some artisanal gear, which are the only fisheries targeting marlin, and various sport fisheries located on both sides of the Atlantic Ocean. The increasing use of anchor aggregation devices (FADs) for various artisanal and sport fisheries increases the vulnerability of these stocks. Results from many assessment models indicate overfishing, particularly in the eastern rather than western Atlantic Ocean.