Amigo you seem to be suggesting that the sole reason for the existence of animals is for humans to eat. I don't agree with this, and IMO it reflects the sickening arrogance that sone members of the human race have, especially towards animals.
Yes we live in a developed and complex Eco system, engineered somewhat by humans, but it is my view that this evolved, there was no intelligent design or creation, therefore the existence of animals is for life itself, the same reason why humans exist. So they don't exist purely for our consumption. We happen to be at the top of the food chain (for want of a better expression), that's just the way it happened.
Animals have a right to life the same as us, as said just because they aren't as intelligent doesn't mean they should be treated any worse. It is their planet and their home aswell. When a surfer gets chewed by a shark, it's a shame. I don't want it to happen, but that's the nature of the beast, and if you venture into its territory, that's what you expect. It shouldn't be hunted down and killed just because humans want to surf. The same goes for man eating big cats etc, when humans encroach on their area.
I have a pet dog. Even the word pet implies it is only their for our benefit, for us to gain satisfaction in petting it. I regard her as a member of the family, and would risk my life without question to protect her. I have a better bond with her than most people, just because she is a dog and not human doesn't lessen her worth.