Industrial fishing via dredging the ocean bottom is wiping out the ocean ecosystem, so you'll be giving up your shrimp soon.
Scavengers at the bottom of the food chain are forbidden for good reason(s).
(1) your immune system isn't the same as a vulture's.
(2) scavengers suck up the deadly toxins corporations dump into the ocean.
(3) killing off the food supply of real edible fish isn't sustainable.
We are long since satisfied that you dont know your biology / ecology / fisheries management.
Most of the shrimp on the market are farm raised, not wild caught.
They are raised in freshwater ponds as well as in salt water.
As for your 'scavengers", they are not at the bottom of the food chain.
They are closer to the top.
Your vulture analogy is worthless, as the vulture's digestive system is evolved to cope with the bacteria in decayed meat, not with PCBs, mercury, etc. And the bacteria do not contaminate the flesh of the vulture.
Too much biology for you, tho, eh?
The bottom of the food chain in the ocean is phytoplankton, followed by zooplankton, both of which are pelagic, not benthic organisms. And they are not scavengers.
The toxins that are taken up are progressively concentrated as one goes up the food chain. Large marine predators like tuna tend to have the highest concentrations.
Biblical food rules make little to no sense.