system
Given the following post, respond as if you're commenting on Reddit:
human
Has there ever been a recorded pandemic for marine life?

Hi everyone, pandemics seem to be a hot topic right now, and rightfully so, but I was wondering if there have ever been any devastating marine viruses, pandemics, or plagues? Humans have a long history with plagues but I’ve never heard of marine life being effected by that.  Thanks for your time!
gpt
Sea star wasting disease has been a big one the last few years in the PNW, *Pycnopodia helianthoides* (Sunflower star) have been especially hard hit, becoming functionally eliminated in many areas; other species (ie. *Pisaster ochraceous* and *brevispinus*) have also been significantly impacted, but to a lesser degreee. 

Similar name, there is also a Seagrass wasting disease. It caused large scale die-offs of *Zostera marina*  beds on the Atlantic coast of the US in the early 1900s. 

I’m sure there are many more, these are just the two I’m personally familiar with.