We land-based creatures live in the midst of a massive extinction crisis, just the sixth one over the past half billion years. What about the oceans?… Now, as tricky as it will be to cut back on overfishing by convincing fish farmers to mend their ways and consumers to change their habits, the even bigger challenge will be to stop trashing the place all of these critters call home. Habitat degradation, according to the Science authors, is the main trigger for the extinction wave we’re now seeing on land, and is probably the biggest threat to cause a similar catastrophe at sea. “If you cranked up the aquarium heater and dumped some acid in the water, your fish would not be very happy,” Malin L. Pinsky, a marine biologist at Rutgers University and an author of the report, told The Times’ Zimmer.