How long do they live? Spur dogfish (often referred to as the Spiny dogfish) can live at least 75 years in the wild [1].

Where are they found? Spur dogfish like to hang out in quite a few oceans including the following: the Northeast and Northwest Atlantic oceans, the Southeast and Southwest Pacific oceans, and the Southeast Atlantic and Southwest Atlantic oceans [2]. This migratory species is found in both shallow and deep waters and even at depths of nearly 3,000 feet  [3]. See figure 1.

Figure 1. Range of Spur dogfish.

What do they eat? Smaller sharks and fish, octopus, and commercial fish, which makes them hated by fishermen because they’re considered a nuisance (I’m going to guess that most commercial fishermen have little to no care about the world around them and the future of said world) [3].

What do they look like? These schooling sharks can reach up to 49 inches in length. They are dotted with small, white speckles across their bodies [3]. See figure 2 and 3.

Figure 2. I wonder why it wasn’t named the Spotted dogfish? Or Spotted shark?
Figure 3. The spots are not so clear in this picture.

How do they reproduce? Spur dogfish are slow to reach maturity at between 18 and 21 years old [4]. They reproduce sexually and are considered aplacental viviparous, which is another way to say ovoviviparous. The pups develop within the parent in an egg and are born live.

How do scientists know how old they are?  Comparison and quantification of  growth completion rates and ages at maturity [2].

So what are we lacking? To figure out a way to travel back in time to the very first moment a human allowed apathy to win over empathy.

  • Although there is no information about the nuclear genome of Squalus acanthias, you can find the mitochondrial genome of this species on the NCBI website.
  • I could not find any information about reproductive senescence in this species, which could be interesting given their slow maturity rate.

Conservation status: The Spur dogfish is listed as vulnerable on the IUCN Red List website. This is mainly due to over fishing and by-catch by commercial fisheries.


  1. García, Verónica B., Luis O. Lucifora, and Ransom A. Myers. “The importance of habitat and life history to extinction risk in sharks, skates, rays and chimaeras.” Proceedings of the Royal Society of London B: Biological Sciences 275.1630 (2008): 83-89.
  2. Fordham, S., Fowler, S.L., Coelho, R.P., Goldman, K. & Francis, M.P. 2016. Squalus acanthias. The IUCN Red List of Threatened Species 2016: e.T91209505A2898271.
  3. Florida Museum of natural History. Spiny Dogfish.  Accessed 10/30/2016
  4. Animal Squalus acanthias.  Accessed 10/30/2016