How long do they live? Shortspine Thornyheads are some of the slowest growing fish in the world and they can live over 100 years [1] and maybe even over 115 years [2]. I need to take a moment to thank the authors of the book in the first reference, The Rockfishes of the Northeast Pacific, the information and images in this book are amazing.

Where are they found? The cold depths of the Sea of Japan, the northern Pacific Ocean, and all the way to the deep waters off the coast of central California. They can be found anywhere in waters from 66 to 3,300 feet deep, but like the rockfishes, adults prefer very deep waters [1].

What do they eat? Smaller fish, shrimp, and other invertebrates [3].

What do they look like? Shortspine Thornyheads can reach 32 inches in length. They have 15 or more dorsal spines, which you probably couldn’t care less about, but that’s one way to tell them apart from other rockfishes, which usually have only 13 dorsal spines [1]. They are usually red or a pink-red color and I’m really starting to feel like a fish nerd and I kind of like it. See figures 1 and 2.

sebastolobus_alascanus
Figure 1. Okay, this fish looks fake it is so pretty.
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Figure 2. Red light is not visible at the depths that  Shortspine Thornyheads generally live at. They look black and not much different than the sea floor to a would be predator, unless you shine a giant flashlight on one…Next to said predator.

How do they reproduce? Shortspine Thornyheads are oviparous, which means fertilization is internal and they release their larvae into the water. Although I found a few papers mentioning the length the fish is at sexual maturity, I couldn’t track down the age of maturity or the age at which this fish stops reproducing. They may not stop reproducing for all we know.

How do scientists know how old they are? Otolith growth patterns and radiometric age validation [2].

So what are we lacking? There’s no information regarding the nuclear genome of Sebastolobus alascanus on NCBI (National Center for Biotechnology Information). Like many of the long-lived fish, we just don’t know much about these species, especially in regards to their reproductive and molecular biology.

Conservation status: They are listed on the IUCN website as endangered. Over-fishing is a massive problem for most fish species.

 

  1. Love, Milton S., Mary Yoklavich, and Lyman K. Thorsteinson. The rockfishes of the northeast Pacific. Pages 114-116. Univ of California Press, 2002.
  2. Cailliet, G. M., et al. “Age determination and validation studies of marine fishes: do deep-dwellers live longer?.” Experimental gerontology 36.4 (2001): 739-764.
  3. NOAA. Alaskan Fisheries Science Center. Shortspine Thornyhead.  http://www.afsc.noaa.gov/Rockfish-Game/description/shortspine.htm. Accessed 9/17/2016.