And in a place like Galapagos, when the fish died, the sea lions that eat the fish also died. Well, oceanically it's mainly a Pacific Ocean phenomenon. But when you move that much warm water, that far across the globe, it changes weather everywhere. To grow plants you need water, you need sunlight and you need nutrients, like fertilizer. In the ocean of course water is not a problem.
Light only penetrates the upper hundred, sometimes even only the upper ten meters of the water.
And nutrients are in the cold rich deep water. So to grow phytoplankton you need the rich cold water to meet with the light zone, which is on top. This usually happens in coastal zones and around the equator. On SeaWiFS data you can see when the nutrients are shut off, there's no life. And then when the warm water recedes and the nutrient rich water is able to get back into the light zone, there's a giant, giant bloom.