Marco polos description about asia made many Europeans curious
Answer: There is pollution in the east river
Explanation: If we think about it cant be a lack of food as it talks about having a large food source. Nor can it be climate change as that would result in a low yellow Perch population. it cant be they aren't able to catch the bird. So the only logical answer is a pollution that the birds are adapted to.
Britain wanted control over the Suez Canal because it was the shortest naval route between Europe and Asia.
They talked with other important people to get in a deal.