They had to fear upon drought. because it was too hot & there was no water to evaporate for it to rain.
This information is important to let the public know what is happening. And it gives people knowledge about what happens. It is also important because, people who read this, would find it rather unpleasant and would have the urge to speak up and try to put it to an end or reduce the rate at which it happens in their society.
I'm thinking that the shellfish could be affected by human activity in the harbor such as pollution.