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Sea lion problem solved in Seattle

Sea lions
For years, hungry sea lions would hang out at the locks and feast on steelhead returning to Lake Washington to spawn  
April 8, 1998
Web posted at: 6:18 p.m. EDT (2218 GMT)

By Environmental News Network staff

(ENN) -- Steelhead trout headed for the fish ladder at Seattle's Ballard Locks have had it easy this spring thanks to the absence of California sea lions, according to the National Marine Fisheries Service.

For years, dozens of hungry sea lions would hang out at the locks from January through April and feast on steelhead returning to Lake Washington to spawn. The feeding frenzy became so intense that the returning steelhead population dwindled to just 70 in 1994.

Fortunately for the steelhead, for the past two seasons sea lions have hardly made an appearance at the locks. They were present for just over two hours during the first 2 1/2 months of 1997. This year, their time at the locks is even shorter: less than an hour from January through March 15.

In fact, only one steelhead has been killed to date by a sea lion this year, by a lone, unmarked animal March 30.

The primary reason for this turn of events, according to Joe Scordino, a marine biologist and marine mammal specialists with NMFS, "is that we permanently removed the three most troublesome sea lions in 1996, one of which had been returning to the locks every year since 1989 to eat steelhead."

The permanent removal came after years of unsuccessful attempts to drive the problem sea lions away. The use of firecrackers, barrier nets, rubber-tipped arrows, foul-tasting fish and even trucking some of the sea lions back to California never panned out for the NMFS.

Locks
Changes to federal law allowed killing problem animals, but the three sea lions removed in 1996 were shipped to Sea World  

A change in the Marine Mammal Protection Act in 1994 allowed sea lions known to be harming steelhead to be targeted for "permanent removal."

The changes to the federal law provided for killing problem animals, but the three sea lions removed in 1996 were shipped to Sea World following the aquarium's offer to house the animals in its facility in Orlando, Florida.

"Although we have observed many sea lions near the Ballard Locks in Shillshole Bay, very few -- perhaps no more than a dozen all told -- ever came up to the dam and ate steelhead," said Scordino.

"The problem was never sea lions in general," he added. "The problem has always been a few sea lions in particular."

With the removal of the sea lions, the number of returning steelhead is up. To date, 95 of the sport fish have been counted passing through the fish ladder.

In 1996, before the "problem" animals were removed, sea lion presence was high -- 95 hours of observed sea lion presence -- and only 38 steelhead were counted at the ladder.

To further discourage any new sea lions from meeting a similar, or worse, fate than their predecessors, the NMFS operates underwater noisemakers that deter sea lions from exploring the locks area in search of food.

Copyright 1998, Environmental News Network, All Rights Reserved


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