Smooth Cornetfish

The bluespotted cornetfish (Fistularia commersonii), also known as smooth cornetfish or smooth flutemouth, is a marine fish belonging to the family Fistulariidae. It is widely distributed in tropical and subtropical waters of the Indo-Pacific region, ranging from 🇯🇵 Japan to the west coasts of the Americas, including 🇵🇦 Panama and 🇲🇽 Mexico's Sea of Cortez, as well as the 🌊 Red Sea. In 2000, it was reported in the Mediterranean Sea off 🇮🇱 Israel. Over the past two decades, this species has experienced a population explosion in the Levantine Sea and has rapidly spread westward, reaching the westernmost parts of the Mediterranean and as far north as the Gulf of Lions by 2007. It is now recorded in all Mediterranean sub-basins and has become very common in the eastern part. Due to its rapid reproduction and negative impact on native fish populations, Fistularia commersonii is considered an invasive species in the Mediterranean Sea. Studies have shown that the Mediterranean population is descended from a small number of ancestors, likely as a result of a single invasion event, and exhibits lower genetic variability compared to its conspecifics in the 🌊 Red Sea.

The bluespotted cornetfish can grow up to 1.6 m (5.2 ft) in length, although the average size is around 1 metre (3 ft 3 in). Its distinguishing feature is its remarkably long and slender body shape. It has a tubular snout, large eyes, and a long tail filament lined with sensory pores, possibly aiding in prey detection. The body coloration ranges from blue-grey to greenish-grey, with two thin blue stripes or lines of dots along the back, becoming lighter towards the front. At night, its body pattern changes to a broad banded pattern.

Typically, the bluespotted cornetfish is a solitary predator, hunting small fishes, crustaceans, and squid. It may also feed in small groups along the seafloor, utilizing its elongated snout to efficiently capture bottom-dwelling fish. These fish excel at preying on juvenile fish residing in seagrass meadows (Posidonia oceanica), which can have detrimental effects on the survival and reproductive success of native fish populations. They can also hover or swim in small schools just below the water's surface. Reproduction occurs via egg laying, with the large eggs hatching and developing externally. The larvae hatch at a size of 6–7 mm (0.24–0.28 in).

Interestingly, the bluespotted cornetfish harbors bacteria in the mucous on its skin, which may enable smoother movement through saltwater. Research on the parasites that inhabit bluespotted cornetfish has revealed that these parasites continue to thrive even as the fish colonizes non-native habitats. This challenges the prevailing theory, known as the enemy release hypothesis, which suggests that parasites would struggle to survive in new environments. The presence of introduced parasites not only impacts Fistularia commersonii but also affects other fish and marine animals in their native habitats.

While the bluespotted cornetfish holds minor commercial significance, being primarily used for fish meal and also sold fresh or preserved, it is also sought after as an aquarium fish.

The species' specific name, commersonii, pays tribute to the French botanist Philibert Commerson (1727-1773).