Octopus is another source of marine collagen which was researched since 1980s.
There are numerous types of collagen and the five most common types are:
Type I: Skin, tendon, ligament, vascular ligature, organs, bone
Type II: Cartilage
Type III: Reticulate (main constituent of reticular fibers)
Type IV: Forms the epithelium-secreted layer of the
basement membrane and the basal lamina
Type V: Hair, placenta and cell surfaces
According to some publication, the main collagen component in the muscle and skin of marine fish, lobster and octopus is Type I collagen followed by smaller amount of Type III.