Classification of Scoliodon : Dogfish

• Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
• Group :- Craniata (Cranium with brain present.)
• Sub phylum :- Vertebrata (Vertebral column present.)
• Division :- Gnathostomata (Jaws and paired appendages present.)
• Super Class :- Pisces (Paired fins, gills and skin with scales.)
• Class :- Chondrichthyes (=Elasmobranchii)
• Order :- Pleurotremata(=squali)
• Family :- Scyllidae
• Genus :- Scoliodon (Dogfish)

Geographical distribution of Scoliodon : Dogfish

Scoliodon has wide distribution. About 4 species are found all along the Indian sea coast. Its presence has been reported from Zanzibar, Srilanka to Malay Archipelago, East Indies, Philippine Islands, Mexico to Panama, Cuba, West Indies and South America. Lower Carboniferous to Recent.

Habit and habitat of Scoliodon : Dogfish

Scoliodon is predominantly found in tropical and subtropical coastal waters, especially in the Indo-West Pacific region.Common habitats include shallow estuaries, bays, and coastal waters, often near the seabed.Its range includes the waters around India, Southeast Asia, and the eastern coasts of Africa.

Behavior:

• Scoliodon is a relatively docile shark and is not considered dangerous to humans.
• It exhibits nocturnal behavior, becoming more active during the night for hunting.

Diet:

• Its diet primarily consists of small fish, crustaceans, and other benthic organisms.
• As an opportunistic feeder, it plays an essential role in controlling prey populations in its ecosystem.

General Characteristics of Scoliodon : Dogfish

• Commonly called dogfish or dogshark.
• Spindle-shaped body, about 60 cm long, is regionated into head, trunk and tail.
• Dorsal and lateral sides of body are pigmented dark grey or slaty grey, while the ventral side is white.
• Head is dorso-ventrally compressed and flattened into snout. It contains ventrally situated slit-like mouth, obliquely situated nostrils and laterally situated protuberant eyes. A little behind eyes there are five pairs of lateral gill-clefts.
• Trunk bears paired fins. A pair of anterior pectoral tins and a pair of posterior pelvic tins.
• Heterocercal tail turned upwards and caudal tin.
• A pair of pigmented lateral lines extends from head to tail.
• Scoliodon exhibits sexual dimorphism. Males are easily recognized by having a pair of intromittent organs, called as claspers. Cloaca is found between 2 pelvic fins.

Reproductive Biology

• Scoliodon is a viviparous species, meaning it gives birth to live young rather than laying eggs.
• Females have a unique reproductive system with a yolk sac placenta that nourishes embryos during development.
• The gestation period is relatively short, and females typically give birth to 4–8 pups per litter.

Economic importance

• Scoliodon has great educational and experimental value because of its availability and size and is a favourite dissection fish for undergraduate students.
• Scoliodon is often caught as bycatch in commercial fisheries and is sometimes used for fishmeal and oil extraction.
• In certain regions, it is consumed as a source of protein, though its small size limits its commercial fishing value.
• Its simple structure and small size make it a model organism for studying cartilaginous fish anatomy and physiology.
• Research on its reproductive system has provided insights into the evolution of viviparity in sharks.

Special features

Sharks are used as human food in many countries. Shark’s fins are dried and then boiled to yield a gelatinous substance favoured for soups. The tanned shark skin shagreen is used to case fine books, jewel boxes and sword handles, etc. Sharks are nuisance to fishermen, because they tear nets, steal captured fishes and take out bait or fish from hooks.

Identification :

Since the animal has raised tail, pointed snout, and above features, hence it is Scoliodon

Conservation Status

• The International Union for Conservation of Nature (IUCN) currently lists Scoliodon as “Least Concern.”
• Despite its stable population, threats such as overfishing, habitat destruction, and pollution in coastal waters could impact its numbers in the future.