TLDR: A species of snake eel typically found in Peru with a maximum northern range limit of Northern California, has been found alive in Washington. This species has only been seen this far north twice prior, however both were already deceased.
Yea my first thoughts were if this behavior was indicative of climate based temperature changes within the waters off our coast. I would hope not, but let’s face it the reality is that something in the environment changed and enabled our snake-eel friend to survive that far north.
Appearances of warm-water marine species off the US and Canadian west coast are common during El Niño years (and other warm water events), and probably reflect short-term warming of coastal waters (for example, see this article) that brings rare fish, invertebrates, and birds northward, but they don’t stay/survive for long. Long-term range-shifts are happening with climate change, but these so far are over shorter distances (for example, this article). Of course, climate change is complex and is changing the frequency and magnitude of the short-term fluctuations, but it’s hard to attribute rare events like the Snake Eel sightings directly to global change.