Did Navy sonar kill porpoises in Puget Sound?

From ANIMAL PEOPLE,  July/August 2003:

FRIDAY HARBOR,  Washing-ton–U.S. National Marine Fisheries
Service strandings coordinator Brent Norberg on July 1 indicated that
tests to find out if Navy sonar killed porpoises in Puget Sound
nearly two months earlier would be complete within another three
weeks.
“In all,  13 dead porpoises were found beached or floating
between May 2 and May 20–eight of them on or after May 5,”  the
Seattle Post-Intelligencer reported.  NMFS recovered eight of the
porpoises,  the Whale Museum at Friday Harbor collected three,  and
two floated away.
On May 5 the destroyer USS Shoup conducted a five-hour sonar
test in the Haro Straight,  between the San Juan Islands and
Vancouver Island.

Salish Sea Charters whale-watch operator Tom McMillan said a
pod of up to 20 whales “abruptly stopped feeding,  gathered in a
tightly knit group,  and swam to shore.  The sonar ‘pings’ were loud
enough for humans to hear on shore,”  the Post-Intelligencer said.
The sonar test ended after Canad-ian officials complained to
the U.S. Navy,  wrote Seattle Times staff reporter Ian Ith.
Tired of waiting for official test results,  Center for Whale
Research founder Ken Balcomb privately obtained his own CAT scan of
the remains of one porpoise.  He reportedly found “hemorrhagic trauma
that could be due to” the sonar exercise.
Suggesting that the strandings and deaths were actually caused by
parasites,  Navy spokespersons warned against jumping to conclusions.
In 2001 Balcomb,  NMFS,  and the U.S. Navy all found
preliminary evidence that sonar caused the strandings of at least 16
whales and the deaths of six after a naval exercise in the Bahamas.
A similar incident was documented in Greece in 1986.
The Puget Sound dolphin deaths added to the controversy long
surrounding U.S. Navy use of Low Frequency Active Sonar,  an even
more powerful system,  believed to be particularly deadly to marine
mammals.  In January 2003 more than 60 representatves of the European
Parliament asked for a moratorium on LFAS use in European waters.