Alligator Pipefish

The alligator pipefish, also known as double-ended pipefish (Syngnathoides biaculeatus), is a distinguished species within the family Syngnathidae. It stands as the sole representative of the genus Syngnathoides. This species inhabits the shallow waters of the tropical and subtropical Indo-Pacific regions, with its distribution spanning from East Africa to Northern 🇦🇺 Australia. The alligator pipefish predominantly resides in seagrass and seaweed habitats, employing a vertical orientation amidst similarly colored vegetation to camouflage effectively. Its elongated, well-camouflaged body can grow up to 29 cm (11 in), though it typically measures around 20 cm (8 in). This species feeds by suction, drawing in its prey.

The alligator pipefish features a distinctive narrow head with a snout adorned with short tentacles. Its body is elongated and tetrahedral, and it possesses a dorsal fin comprising 38 to 48 soft rays alongside anal fins with four soft rays. The tail is notably long, tapering, and prehensile, devoid of a tail fin, which the fish employs to secure itself to vegetation. The coloration of the alligator pipefish generally aligns with its surrounding environment, exhibiting shades of green, brown, or grey, with females sometimes displaying blotches or a white zigzag line along the abdomen.

Geographically, the alligator pipefish is distributed throughout the tropical and subtropical 🇮🇳 Indian and 🌊 Pacific Oceans, with its presence recorded from 🇿🇦 South Africa and the East Coast of Africa, extending through the 🌊 Red Sea, 🇮🇳 India, 🇯🇵 Japan, 🇮🇩 Indonesia, the 🇵🇭 Philippines, 🇵🇬 New Guinea, and various Pacific Islands. In 🇦🇺 Australia, its range extends from Geraldton in Western Australia across the coastlines of the Northern Territory and Queensland to Batemans Bay in New South Wales. The species thrives in varied aquatic environments, including lagoons, reef flats, bays, estuaries, seagrass meadows, and floating algae masses, typically at depths under 5 meters (16 ft).

Characterized by inefficient swimming, the alligator pipefish navigates through an undulating movement of its pectoral and dorsal fins. Its diet comprises zooplankton and small aquatic organisms, including amphipods, mysids, shrimps, other benthic invertebrates, and small fish. Exhibiting sexual dimorphism, males are larger and reach maturity at approximately 180 mm (7 in). Breeding occurs during the summer months in Moreton Bay, Queensland, although it can take place year-round in Papua 🇵🇬 New Guinea. Females produce between 60 and 200 eggs, which the male then incubates in a brood pouch on his abdomen until they hatch. The species displays monogamous tendencies, with all developing eggs at the same stage, presumably originating from a single female.

The dried alligator pipefish holds significance in traditional Chinese medicine under the name "hailong." The species is also a commodity in the pet trade for aquarium enthusiasts and is maintained in public aquariums for educational and research purposes. Currently, no comprehensive studies have been conducted on the population trends of this species, leaving the International Union for Conservation of Nature with limited information regarding the sources of traded specimens. Consequently, it remains unclear whether these individuals are wild-captured, originate from dedicated fisheries, are bycatch, or are captive-reared. Due to these uncertainties, the IUCN has classified the alligator pipefish as "data deficient" concerning its conservation status. In 🇦🇺 Australia, it is recognized as a listed marine species under the Environment Protection and Biodiversity Conservation Act 1999.