Rare sharks with stripes
The Striped smoothhound (Mustelus fasciatus) is a shark belonging to the family Triakidae, found on the continental shelves of the subtropical southwest Atlantic from southern Brazil to northern Argentina. They have a unique and unmistakable look but are rare to see. Like other members of its family, they have flat, pavement-like teeth great for crushing prey.
Family: Triakidae – Houndsharks
Common Name– Ground Sharks
Common Name– Houndsharks
Status: IUCN Red List CRITICALLY ENDANGERED
Average Size and Length: They are born around 39 cm/1.2 feet. Mature males have been measured over 62 cm/2 feet. The maximum recorded is 155 cm/5 feet.
Teeth and Jaw: The teeth are mostly flat arranged a pavement like fashion, ideal for crushing prey. There are no cusps, and the crowns are broadly rounded.
Head: The head is long and angular, and the snout is acutely pointed. The nostrils are widely spaced. The eyes are very small with a yellow spot in front of each orbit. It has a much more angular and longer head than the Speckled smoothhound.
Tail: There is a short caudal peduncle.
Demographic, Distribution, Habitat, Environment and Range: The Striped smoothhound can be found on the southwest Atlantic in southern Brazil, Uruguay and northern Argentina (30° S and 47° S). They are found in temperate seas on the continental shelf and uppermost slope on the bottom inshore and offshore possibly from the intertidal zone to 230 feet. They are rarely seen at 33-1,640 feet off of southern Brazil. They are considered subtropical, demersal.
Young sharks are found on beaches of depths between 1-16 feet, juveniles occupy inshore waters at between 49-164 feet. Adults are found at deeper depths.
Diet: More than likely they feed on crustaceans.
Aesthetic Identification: The Striped smoothhound has vertical dark bars (black brown in color) and narrow transverse bands, on an unspotted body. This is observed in the young sharks. They are somewhat stalky in shape. There are broadly triangular unfringed dorsal fins with narrow edges. Its look is very distinctive, and it is closest related to the Speckled smoothhound.
Biology and Reproduction: They are viviparous with a yolk sac placenta. Pregnant females migrate into shallow waters (less than 66 feet deep) along the Rio Grande do Sul coast of Brazil to give birth from October to December after a gestation period that lasts between 11 and 12 months. Striped smoothhounds have 4 to 14 pups per litter, with an average of 8 pups. The longest reported lifespan was 24 years.
Behavioral Traits, Sensing and Intelligence: Unknown.
Striped Smoothhound Future and Conservation: They are critically endangered. They are rarely seen, very uncommon to rare. Between the 80’s and 2000’s, populations drastically decreased due to heavy fishing by gillnets off of beaches. In Brazil, trawl fishing at depths of less than 10 m/33 feet is illegal, but enforcement is almost nonexistent.
Striped Smoothhound Recorded Attacks on Humans: Not a threat to humans.