The Big Apple has become the new sea-life hot spot.

Warm-water fish from southern regions are making the Big Apple their new home — as rising temperatures are attracting marine creatures used to balmy conditions, according to a new study.

Fish like the massive Cobia — similar to the tropical mahi-mahi — have been spotted gentrifying aquatic neighborhoods like Jamaica Bay, where the flounder and mackerel that have long lived there are leaving to find cooler regions.

“Eventually we’re going to have a fish community that resembles what’s in Chesapeake Bay right now,” biology professor and study co-author John Waldman told The Post.

“I can’t believe the changes in my lifetime.”

The first-of-its-kind study is considered the largest effort to date to understand how the fish of Jamaica Bay have responded to rising water temperatures and other climate changes.

Waldman, along with former biology professor José D. Anadó, evaluated the change in fish species between 1989 and 2017 in the Brooklyn-Queens bay, where rising temperatures have outpaced other parts of the globe.

The summer water temperatures in New York have increased by more than 2°F in just over two decades — a difference that is five times greater than the 0.2°F per decade increase in global upper ocean temperatures, Waldman said.

That means that Jamaica Bay has transformed into a warmer hotspot that attracts the likes of the massive Cobia, a Gulf of Mexico species that had never been found in the Big Apple until recently.

Populations have surged so significantly that fishing expeditions have turned their sights on the Cobia, which is renown for being as delicious as its more famous cousin, the mahi-mahi.

Redfish, Black Drum and tiny skilletfish have also invaded Jamaica Bay in recent years.

“All of a sudden, they’re all over the place,” Waldman said.

The same warm conditions that are enticing the newbies into Big Apple waters are kicking the old fish out, however.

White perch, Whiting and mackerel are just some of the species that have become hard to find in the outer borough bay, as well as as well as various types of flounder, which Waldman said was considered a “primary fishing species” before it seemingly vanished.

“Fishermen would fish intensively in spring and fall for these delicious flounder. Now they’re hardly ever seen anymore,” the expert on human impacts on fish populations explained.

The Big Apple-based study highlights a larger, worldwide trend of fish moving north and into deeper waters as their homes slowly transform into a warmer climate.

Two massive spikes in water temperatures in 1999 and 2012 — and another expected for this year — have only exacerbated the migration.

Queens College researchers discovered the alarming change by capitalizing on nearly one million specimens collected over the last 28 years.

During the same time period every fall, scientists skim the shallow waters of Jamaica Bay to evaluate fish populations and compare how they are changing.

The data confirms the alarm bells that fishermen have been sounding for years — and scientists warn there’s no hope of reversing the northward migration trend unless the globe gets climate change under control.

“There’s no doubt that within all of our lifetimes, we’re not going to see a turnaround where the water suddenly get cooler and cooler,” Waldman said.

“That’s not necessarily tragic. It’s just one of the outcomes of this planetary change that we’re imposing.”