On Thursday, authorities said that a dead whale that was discovered washed ashore this week along a southern Alameda County wildlife area is the second deceased whale found in 2015 in bay waters.

US Fish & Wildlife Service spokesman Doug Cordell said that the whale was at first spotted floating near the San Mateo Bridge during the weekend and ultimately was seen at the Don Edwards San Francisco Bay National Wildlife Refuge, on Wednesday. The whale was around 25 feet long.

Cordell said when the whale was found on the shore just west of Coyote Hills Regional Park near the Dumbarton Bridge, it was much decomposed and presently, there are no plans of moving it.

Cordell added that the species and reason of death is not known yet, but on Thursday afternoon, biologists from Marine Mammal Center were there to collect tissue samples for conducting a necropsy.

Previously, the carcass of an immature fin whale around 52 feet long was discovered lodged under an Alameda pier in the Oakland Estuary in August. As per the Marine Mammal Center and the California Academy of Sciences in San Francisco, scientists found that the cause of its death was blunt force trauma caused by a ship strike.

Besides this year, the Marine Mammal Center responded to a whale in San Francisco Bay earlier in September 2010, when they found a male fin whale on the bow of a ship docked at the Port of Oakland.

In 2015, the center has responded to six stranded whales off Northern California coasts, out of which two were found to be consistent with ship-strike injuries, two were unknown, one was a mess and another case is waiting for the results of the test.