BOSTON — A member of a species of critically endangered whale that is struggling with poor reproduction has been found dead off of Massachusetts.

North Atlantic right whales are among the most endangered marine mammals, numbering no more than 450. The National Oceanic and Atmospheric Administration says the second right whale mortality of 2018 has been reported off of Martha's Vineyard.

The NOAA says the whale was reported dead on Sunday. The agency says the whale was too decomposed to bring to land, but tissue samples were taken to try to learn more about it.

There were 17 right whale deaths last year. Scientists say they are alarmed that no new calves were spotted this year in the whale's calving grounds off of Florida.