Marine collagen is made from the skins/scales of fish, while bovine collagen (sometimes referred to as "grass-fed" collagen) is made from cowhides.
Marine collagen peptides have a lower molecular weight than bovine peptides (smaller particle size) making them more bioavailable and effective.
Wild-caught marine collagen like Landish's is also guaranteed to be free of hormones and antibiotics, which is almost never the case for bovine collagen.
Finally, Landish's marine collagen is made in North America (in Canada), whereas the vast majority of it is imported from Asia.