Shark’s blood contains urea, which breaks down to ammonia after it dies. For this reason it is essential to bleed sharks you intend to eat immediately after capture. Spiny dogfish is very good to eat. I have eaten plenty of them over the years. Most of us will have eaten dogfish unwittingly as it is often sold as fish and chips.
It is a dense meat and is little affected by freezing. I always freeze it even if I am going to eat it the next day as this firms the flesh.
A good way to cook it is in a casserole dish in the oven. Buy a few hundred grams of frozen smoked hoki or cod from the supermarket. Cut it up in pieces about 2 inches long and place in the dish. Do the same with 3 or 4 times the amount of spiny dogfish fillets. Add knobs of butter, pepper, parsley, and a bottle of cream. Bake in the oven until done. When all cooked together the mild smoked flavour goes through the dogfish and you can’t tell which fish is which. You can add mullet, kahawai, blue cod and so on if you wish.
You can also batter dogfish or cover in bread crumbs. Either way it is best to freeze it first.