Scientists first spotted the Blob, a patch of unusually tepid water in the Gulf of Alaska, in late 2013. It expanded until it covered an area about the size of the continental United States. While it might have been out of sight for many, marine heat waves like the Blob can have devastating effects on marine life and related industries. The Blob was the largest and longest-lasting marine heat wave on record and may signal what's to come, with fish farms, scallop operations, and snow crab pots already falling victim to oceanic overheating.

The Blob's impact extended across several species, leading to the death of 1 million seabirds and the vanishing of 100 million Pacific cod. The warming triggered toxic algal blooms and disrupted fisheries, causing havoc for industries such as the Dungeness crab business. The economic toll on fisheries and coastal economies reached up to $3.1 billion. The situation was aggravated by climate change and the El Niño weather pattern, leading to more marine heat waves.

Marine heat waves, caused by changes in air and ocean currents, can lead to an increase in ocean temperatures. The heat can have disastrous effects on fish species that prefer cold water, like cod and salmon. The warming also affects spawning habitats and food availability. Heat waves can trigger ecosystem changes such as algal blooms, and shifts in feeding grounds, which can have cascading effects on the fishing industry.

As global warming continues, marine heat waves are becoming more frequent and severe. Particular areas of concern include the Gulf of Maine and the northeastern Pacific. While there might be some temporary benefits to certain species like lobsters, the long-term impacts could be detrimental. However, there is a potential silver lining: new fisheries might open up as species migrate to new areas, providing opportunities for some winners in this situation.