New England fisherman are struggling because of climate change catching fewer fish due to the rise in ocean temperatures . Why don't fish do well in warm waters?

Maybe swordfish and other warmer-water species will migrate farther north to make up for the lost cod and halibut? On the plus side it will mean another bumper crop of lobsters like happened back in 2012 when water temperatures peaked then too.

The fish population (and ocean temperatures) run in cycles just like everything else. I remember years ago when the New England fishermen were "carping" about fewer fish due to over-fishing off the continental shelf by Soviet Russian fishing vessels. Guess they have to have something to blame for a bad year or two.

probably for the same reason we dont do good in hot weather

Did you know that fish make it just fine in all waters depending on the fish?  They are very sensitive creatures.  You don't take an animal used to 110 degrees and put him in the Arctic.   You don't put a fish in a different climate of even one degree because they are attuned to responding to temperature, light, sound and smell in a completely different manner  than we as humans respond.

Any miniscule change can wreak havoc.   This is why aquariums are best left to experts.  I was fortunate enough to have friends who owned a pet store and they always had the best aquariums in their house because they knew what the heck they were doing.  I couldn't even begin to take the time to make those expensive fish thrive. It is a full-time hobby because fish are very delicate creatures.

Aquarium Water Temperature 

• To make temperature reading easy, consider purchasing an adhesive temperature strip that can be applied to the outside of your aquarium glass. They are inexpensive and available at your local fish retailer.
• Monitor the sun – Too much sunlight can cause algae growth. If you are installing a new aquarium, place it away from a window. If your existing aquarium is near a window, use a shade to reduce the amount of ambient light.
• Avoid heat — never place an aquarium above or near a heat source or air conditioner. You want to keep the area’s temperature as stable as possible.
• For all species of fish, there is a middle ground in which they are happiest, and they must be kept within that range for optimum health. Examples: Tropical fish – 72º - 80º F (optimal is 78º), Common Goldfish – 65º - 68º F, Fancy Tail Goldfish – 65º - 72º F
• Submersible heaters are the most popular. Some are adjustable and others are pre-set at 78º for your convenience.
• Be sure to purchase a heater that is properly rated wattage-wise for your tank.
• Never remove a heater from the water if it is still turned on. Unplug it first, let it cool, and then remove it.

I'm no marine biologist so my opinion here doesn't count.

Based on what I've seen of nature documentaries, this is my best guess.

Some fish do very well in warm waters but each species is adapted to fit in its natural habitat within the normal variations. Each returns by instinct to its place of origin to breed. If the water temperature is warmer, the fish does not have the behavioural adaptability to move further north to find new breeding grounds.

Eggs are particularly sensitive to changes in temperature. They won't grow into hatchlings unless the temperature is just right. In addition, for some species, a one-degree rise in temperature produces all males. If too many are born male, there are fewer females, hence less offspring the next generation.

Another problem is that marine environments are typically much richer in algae and food sources where the waters are cold. If there is less food at the start of the food chain, there will be fewer fish throughout all species.

There are other problems affecting fishermen everywhere. Estuaries and river mouths are the favouring spawning grounds of many fish because they shelter the sprats. Deltas and tidal backwaters near coastal cities are being dredged and developed for housing. Agricultural pesticides and weedicides end up downstream and in the breeding zones of fish. The licensed take allowed by governments is typically behind the scientist's estimations of sustainable catch rates.

Thank you for your thoughtful, helpful and informative reply hartfire. I appreciate it! :)

Some folks LOVE hot weather pearl. Jim's oldest son and daughter-in-law used to live in Oregon.  They've lived in Buckeye, Arizona the last few years. She LOVES it. Her husband? Not so  much. You know it gets very hot in southern Arizona. Thank you for your reply! :)

Thank you for your informative reply Sharonna and Happy July 4th Monday! :)