There are two meanings of the word spine: 1. The backbone of a creature that extends from the bottom of their head/skull all the way down their back. And 2. a stiff, pointed, part that sticks out from a creature. E.g. the pointy spines of a fish or kina.
Kina, or sea urchins, are a small sea creature the lives in shallow water. They have a round shell which is covered in sharp needle-like spines. Kina are eaten by crayfish, as well as humans, and they like to eat seaweed or kelp.
Crayfish, or kōura in Māori, are also called Spiny Rock Lobster. They are a creature with long antennae, no claws, and a hard 'exoskeleton' or shell which they need to cast off in order to grow bigger. In some areas it is customary for Māori to make sure that the kōura has all of it's limbs when taken. Why? If a kōura loses a leg or antenna when it is taken, other kōura might see that as a reason to leave the area!