With hundreds of shark species, few are as iconic as the Thresher with that whiplike tail! Truly fascinating and still, sadly, so much left to be discovered of this vanishing shark.
SCIENTIFIC NAME: Alopiidae
COMMON NAME: Thresher shark (3 known species)
*Also commonly known as: common thresher, fox shark, sea fox,
swiveltail, whip-tailed sharks, slashers, swingletails, or thrasher sharks
pelagic or fine-tooth threshers (Alopias pelagicus)
bigeye thresher sharks (Alopias superciliosus)
common threshers (Alopias vulpinus)
TYPE: Fish
AVERAGE LIFE SPAN: Suggested to live up to 50 years; these sharks are slow to reach sexual maturity and give birth to few young which makes them especially vulnerable to overfishing and oceanic threats.
IUCN status: Endangered
SIZE:
Threshers can grow 9 - 20 feet and weigh up to 1,000 pounds; Their whip-like tail constitutes nearly 50% of shark's total length!
DISTRIBUTION:
Threshers are an oceanic and coastal species that inhabits tropical and colder, temperate waters worldwide.
DIET:
Thought to stun prey using their powerful tails, Threshers' diet include: squid, octopus, crustaceans although they primarily hunt small schooling fish like herring or sardines.
Threshers are known for their impressive speed (upwards of 30 mph) and breaching ability. Makes sense, since these sharks eat mostly bony schooling fish, like bluefish or mackerel, which require great speed and maneuverability to catch. Thresher sharks hunt opportunistically by day and night, which makes them vulnerable to fishing operations.
Check out the Thresher in action! In this quick clip, we see how these sharks use their tails to grab an easy meal:
Subscribe to Discovery Channel's YouTube Channel
CONSERVATION:
The lack of data from other locations make it difficult to access population fluctuations internationally, although it is know the populations are in decline worldwide.
The IUCN notes to prevent further overfishing, it is recommended that Common Thresher be subject to regional and national catch limits based on scientific advice and/or the precautionary approach, as well as improved reporting of catch and discard data and full implementation of all commitments agreed through international treaties.
In 2016, all three thresher sharks were added to Appendix II of the Convention on International Trade in Endangered Species (CITES), which requires exports from CITES Parties to be accompanied by permits based on findings that parts are sourced from legal and sustainable fisheries.
Tail of Trouble
Like most larger shark species, Threshers reproduce very slowly and give birth to few pups at a time, making them very vulnerable to overfishing. To make matters worse that tail of theirs often means trouble as recreational fisheries catch them in nets or longlines, often hooking these sharks by the tail ("foul hooked" or "snagging").
'Foul hooking' is when a shark is hooked somewhere that isn’t the mouth, such as the fins or the head.. Thresher sharks see the bait, use their tail to try to stun it then getting snagged on the hook. This leads to fishermen reeling these sharks in by the tail. When a shark gets pulled backwards, they can’t get water over their gills and have a hard time breathing.
Threshers are commonly hunted for their meat, liver oil, skin, and fins (for such uses like shark-fin soup). Threshers have been widely caught in offshore longlines by the former USSR, Japan, Taiwan, Spain, Brazil, Uruguay, USA and other countries. The northwestern Indian ocean and eastern Pacific are especially important fishing areas. Additionally, since the thresher is classed as a big game fish, anglers in the USA and South Africa fish them for sport.
How can we save the Thresher?
With each of the three thresher species endangered and threatened with the very real possibility of extinction in the coming decades, more needs to be done to safeguard sharks outright.
Becoming an informed consumer is vital to the survival of not only sharks but the planet as a whole. Knowing where your everyday products come from, reading ingredients and asking questions are all very important tactics if we are to make positive strides in conserving our oceans.
Continue learning about the plight of these sharks as well as the processes that are putting them in danger. Still so much about sharks and their habits are unknown and non-profits are underfunded to access these animals fully. You can make your voice heard by signing petitions to end the fin trade and not buying any seafood that isn't sourced responsibly and sustainably. We need your help more than ever to help conserve, protect, and save the seas!
Post Sources:
Check out our sources for this shark profile and read more in-depth
details on the Thresher Shark.
(UFL)FloridaMuseum
Commentaires