During the second half of last year — the hottest recorded year in U.S. history — ocean temperatures off the East Coast hit their highest temperatures in the 150 years measurements have been kept. It's not a comforting record.

Data from the National Oceanic and Atmospheric Administration shows that during 2012, ocean temperatures hit 14 degrees Celsius, or 57.2 degrees Fahrenheit, the highest ever recorded. Over the past thirty years, the temperature was typically under 12.4 degrees. "The Northeast Shelf’s warm water thermal habitat was also at a record high level during 2012," the report states, "while cold water habitat was at a record low level."

The NOAA's Kevin Friedland provided us with the temperatures since 1854.

As the chart shows, the temperature in 2012 passed the previous high, recorded in 1951.

Of the four sections of the ocean tracked by the NOAA — Mid-Atlantic Bight, Southern New England, Georges Bank, the Gulf of Maine — the northern three saw all-time highs.

There are a number of implications of this temperature rise. One of the most immediate, as the NOAA notes, is to sealife, populations of which are moving further north on the Continental Shelf — possible bad news for fishermen and lobster-lovers.

Temperature is … affecting distributions of fish and shellfish on the Northeast Shelf. The advisory provides data on changes in distribution, or shifts in the center of the population, of seven key fishery species over time. The four southern species - black sea bass, summer flounder, longfin squid and butterfish - all showed a northeastward or upshelf shift. American lobster has shifted upshelf over time but at a slower rate than the southern species. Atlantic cod and haddock have shifted downshelf.

Warmer ocean water can also disrupt energy production. Last August, a nuclear power plant in Connecticut was forced to shut down a reactor after the water used to cool it was too warm to do the trick.

Perhaps most alarming (particularly in light of our story earlier today), warmer seas are higher seas. Like every other fluid, water expands as it warms. And since water can't expand down, it expands up, raising sea levels. A report last summer indicated that levels on the East Coast were already rising three to four times faster than the rest of the world. Only part of that is due to temperature differences.

After the temperature spike in 1951, it's worth noting, temperatures eventually went back down. How much of last year's increase might be part of a cycle isn't clear. NOAA scientists seem inclined to think that it's not.

Photo: A resident of New Jersey walks through a Sandy-flooded street. (AP)