ANCHORAGE — A necropsy has been completed on a 50-foot fin whale discovered Sunday on the bow of a cruise ship entering an Alaska port.

A cause of death for the endangered animal, however, was not immediately announced.

“It’s under investigation,” said Julie Speegle, spokeswoman for the fisheries section of the National Oceanic and Atmosphere.

The whale was spotted just after 5 a.m. Sunday on the bulbous bow of the Zaandam, a Holland America Line cruise ship, as it prepared to dock in Seward. Spokeswoman Sally Andrews in an email said an officer preparing the ship for arrival just after 4:30 a.m. had not seen the whale.

The company was not aware of whales in the area and has a program to avoid striking them if sighted. Ships can reduce speed or alter course, Andrews said.

Fin whales feed on schooling fish and invertebrates. The average adult male fin whale is 70 feet long and 45 tons. The whale carried by the Zaandam was a juvenile male.

The carcass was towed to a beach for the necropsy. A private Alaska veterinary pathologist working with NOAA Fisheries, Kathy Burek Huntington, was the lead pathologist.

“This whale was a very fresh, young fin whale, which gave us an amazing opportunity to conduct a full necropsy and obtain the full spectrum of samples,” Huntington said in a statement provided by Speegle.

Researchers took samples allowing testing for exposure to harmful algal blooms. Samples will allow a look at the whale’s current and historical diet, genetics to determine stock, contaminants and pre-existing conditions. Ear plugs will allow a determination of age.

“These necropsies don’t just find COD (cause of death), but help answer a host of questions about these endangered species,” Huntington said.

The whale was carried on the ship’s bulbous bow, an underwater extension of the main bow that is designed to avoid making waves.

NOAA Fisheries has three options for disposing of the carcass, Speegle said. It would be cost-prohibitive to tow it to open water. The agency could “let nature take its course” and leave the carcass to scavengers.

There’s also consideration, Speegle said, for burying the carcass on the beach and digging up the bones later for re-articulation and display.