Exocoetus sp.

INTRODUCTION

Exocoetus volitans, commonly known as the Tropical Two-Wing Flying Fish, is a species of flying fish found primarily in tropical and subtropical ocean waters. This species is well-known for its unique ability to leap out of the water and glide over its surface for considerable distances, a behavior thought to be an adaptation to escape predators. Like other flying fish species, Exocoetus volitans has developed specialized morphological features, particularly in its fins, that allow for this extraordinary ability.

MORPHOLOGICAL FEATURES

Exocoetus volitans has a streamlined, elongated body adapted for both swimming and gliding. Its most distinctive feature is its enlarged, wing-like pectoral fins, which enable it to glide above the water surface.

• Body Shape: The body is elongate and slender, adapted for speed and agility in water. It has a slightly compressed body, which aids in efficient swimming and gliding.

• Size: The species typically grows to a maximum length of around 30 cm (12 inches), though individuals in different regions can vary slightly in size.

• Fins:

• • Pectoral Fins: The pectoral fins are significantly enlarged and resemble wings, facilitating gliding. They extend far beyond the base of the pelvic fins and give the fish its characteristic “flying” capability.

• • Pelvic Fins: These are moderately large but smaller than the pectorals, and they assist in stability during gliding.

• • Dorsal Fin: The dorsal fin is located toward the rear of the body and is smaller in size.

• • Caudal Fin: The caudal (tail) fin is deeply forked, with a larger lower lobe, aiding propulsion when the fish is launching out of the water.

• Coloration: The body is typically bluish or silver on the sides and white on the belly, providing some camouflage against predators when viewed from above or below in the water.

• Scales: The scales are small, smooth, and cycloid, reducing water resistance during rapid swimming.

HABITAT AND DISTRIBUTION

Exocoetus volitans is primarily found in tropical and subtropical waters around the world. It inhabits the surface layers of open oceans, generally preferring the epipelagic zone where sunlight penetrates, and temperatures are warmer. This species is distributed in the Atlantic, Pacific, and Indian Oceans and is especially common in regions with warmer surface waters.

• Geographic Range: It is found in warm seas worldwide, especially in the Atlantic Ocean, Mediterranean Sea, and parts of the Indo-Pacific region.

• Preferred Habitat: Exocoetus volitans prefers the open ocean (pelagic) and stays near the water surface, usually at depths of 0-20 meters. It is often found in areas far from shore, although occasionally it may be observed near coastlines, especially in regions where currents concentrate plankton and other food sources.

ECOLOGY

The ecology of Exocoetus volitans is shaped by its unique adaptation to flying or gliding over water, which helps it evade marine predators. It has evolved behaviors and physical traits that allow it to survive in the challenging open-ocean environment.

• Diet: Exocoetus volitans is primarily omnivorous, feeding on plankton, small crustaceans, and a variety of other tiny marine organisms. It often takes advantage of areas rich in plankton, such as upwellings or regions where ocean currents concentrate food sources.

• Predators: The flying fish is preyed upon by a wide range of larger pelagic predators, including dolphins, larger fish like tunas, marlins, and swordfish, as well as seabirds. Its ability to leap out of the water and glide is a primary defense mechanism to escape such predators.

• Behavior: This species is typically found in schools and displays the characteristic behavior of gliding above the water’s surface. When threatened, Exocoetus volitans accelerates to gain enough speed before leaping out of the water and extending its pectoral fins to "fly" above the surface, sometimes covering distances of up to 200 meters.

REPRODUCTION AND LIFE CYCLE

Exocoetus volitans follows a typical reproductive strategy for flying fish, involving external fertilization and laying eggs in open water.

• Spawning: Reproduction generally occurs in warmer months when water temperatures are optimal. Spawning is believed to occur near the surface of the open ocean, though exact timing may vary by location and environmental conditions.

• Eggs: After external fertilization, females lay spherical, sticky eggs that often adhere to floating debris or vegetation in the water, such as seaweed. The adhesive quality of the eggs helps them avoid drifting away and keeps them in favorable conditions for hatching.

• Larvae: Once hatched, the larvae are planktonic, meaning they drift with ocean currents and feed on microscopic organisms. The larvae bear little resemblance to adults, with larger heads and proportionally smaller bodies.

• Juvenile Development: Juveniles begin to resemble adult flying fish as they grow, developing the large pectoral fins necessary for gliding. They feed primarily on zooplankton until they are large enough to transition to a more varied diet.

• Life Span: The typical life span of Exocoetus volitans is thought to be around 2 to 5 years, although detailed studies on lifespan are limited.