Increased ocean temps have been in the news a lot in recent weeks, so I don't grok this reply.

Edit:

Later in the Wikipedia page:

Increasing seasonal temperatures and decreasing salinity levels seem to favor a greater concentration of Vibrio within filter-feeding shellfish of the U.S. Atlantic seaboard and the Gulf of Mexico...

According to the CDC, V. vulnificus infections in the Eastern United States increased eightfold from 1988–2018 and the border of where these infections occur has migrated 48 km Northward each year.

I think what that phrase means is that the temperature in one or more of the seasons has been increasing over the years.