These are top-level predators. Like us, they eat anchovies, squid, salmon and mussels. They are sentinels for human health, because they share our ecosystems and prey. We may see impacts in sea lions before people - they could be an early warning.

I wouldn't eat shellfish during any sort of harmful algal bloom, especially not if I was pregnant.

I believe that these sea lions that are washing up along the coast are actually acting as important canaries in the coal mine, warning us of some ocean changes that contribute in fact to human health.

We thought at the time that it was linked to the fact that it was an El Nino year, but we've seen it every year since then. It's a big mystery.

The fact that acclaimed actors such as these continue to come and share their craft with us is a testimony to the enduring strength of this franchise. We are also proud to welcome back Tom Hanks, who appeared on the show over seven years ago. His body of work since then - on both sides of the camera - is enormous, and we anticipate this next chapter will be as entertaining as the first.

Mercury is a potent toxin that interferes with the human nervous system. Reducing this hazard will be a major public health breakthrough.