The Greater Thames Shark Project

spurdog

In 2020 ZSL started a pilot project to gather data on three of the small sharks that live in the outer estuary: Tope (Galeorhinus galeus), Starry Smoothhound (Mustelus asterias) and Spurdog (Squalus acanthias).  According to the most recent IUCN assessments, tope is now a critically endangered species globally and is facing an extremely high risk of extinction in the wild. Starry smoothhound has also recently been downgraded to near threatened, meaning its population trend is decreasing and is one step away from being vulnerable to extinction. Tope and starry smoothhound both give birth to live young and both are thought to use the estuary as pupping rounds and nursery habitats for their young. It is therefore crucial to collect data on these sharks to ensure their long-term survival in the wild. 


To gather this vital information, ZSL has partnered with several skippers from charter fishing vessels to collect information about the sharks they catch and tag the larger individuals. Over time we hope to develop this project further so that we can start answering some crucial questions, such as: 

1.    What is the relative number of sharks that use the Greater Thames Estuary?
2.    What habitats are important to these sharks?
3.    Do they pup in the estuary and if so where?
4.    How long do young pups stay within the estuary to grow? 
5.    If sharks are born in the estuary, do those same sharks return to have their own young? 

This project has only recently started and there is so much more to find out about these amazing creatures, and you can help us. If while fishing you catch a shark that has a small, yellow ZSL.org tag below its dorsal fin, you can report it here

Species Information

Tope (Galeorhinus galeus)

  • The only shark in the genus Galeorhinus 
  • Also known as the School Shark, Soupfin Shark, Snapper Shark, and the Vitamin Shark.
  • Historically caught for ‘liver oil’. 
  • Critically Endangered globally on the IUCN Red List of Threatened Species.
  • Can grow up to 190 cm long and live for over 50 years. 
  • Mature between 10 to 17 years old and only give birth to pups every two to three years. It has recently been discovered that they return to the same spot every three years as part of their reporductive cycle.  
  • Highly migratory - moving towards to poles in the summer to pup and towards the equators in winter 
  • A tope that was tagged in Scotland turned up over 5 years later in Sicily in the Mediterranean.
  • Adult tope feed on cephalopods and pelagic fishes, whereas juvenile tope prefer to feed on benthic invertebrates.


Footage of tope provided by Jake Davies & Natural Resources Wales

Starry Smoothhound (Mustelus asterias)

  • Commonly referred to as ‘Hound Sharks’
  • Starry Smoothhound is listed by the IUCN red list as Near Threatened – meaning that their population trend is decreasing and one step away from being vulnerable to extinction.  
  • Smaller sharks with a maximum size of 140 cm.
  • Normally have a scattering of small, bright white spots along their back, which give them their name of ‘starry’. 
  • Through genetic studies, it has been shown that they are the only species of smoothhound in our waters 
  • Found at depths of up to 200 metres and feeds almost exclusively on crustaceans
  • Offspring from 3 different fathers have been found in a single litter
  • Understudied shark with limited data but increasing commercial interest.


Thank you to Jake Davies for this footage

Spurdog (Squalus acanthias)

  • Also known as the Spiny Dogfish, Cape Shark, or Piked Dogfish. 
  • They have sharp spines in front of their first and second dorsal fins. 
  • Lives on the continental shelf of temperate seas worldwide, including the Northeast Atlantic.
  • Can inhabit deeper waters up to 900m, but usually found in waters shallower than 200m.
  • They are a schooling shark with gestation periods of up to 24 months and a long generation time of up to 40 years, which makes it vulnerable to overfishing.

Spurdog
Spurdog

 REPORT YOUR SHARK TAG HERE 
 

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