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GLIN==> FISHERIES ADVISORY: Large Alewife Die-Off in Lake Michigan Likely



> Release:  IMMEDIATELY
> June 16, 2000
> 
> For more information, contact:
> Philip Moy, Wisconsin Sea Grant Fisheries & Nonindigenous Species
> Specialist, phone (920) 683-4697, email pmoy@uwc.edu
> 
> 
> Another Big Alewife Die-Off Likely This Year
> 
> MADISON, Wis. (6/16/00) - Coastal residents should watch out for a repeat
> of last year's unusually large alewife die-off in Lake Michigan, according
> to University of Wisconsin Sea Grant Fisheries Specialist Philip Moy.
> 
> "Much depends on the weather over the next few weeks, but two factors make
> it likely we will have another large die-off this year," Moy said. "We
> still have lots of alewives from the large 1995 year-class that are near
> the end of their normal 6- to 7-year life span, plus a large population of
> weak young alewives from the 1998 year-class that are now reaching
> spawning age."
> 
> Originally from the Atlantic Ocean, alewives are poorly adapted to life in
> fresh water and more vulnerable to fluctuations in water temperature than
> native freshwater fish, according to Moy. The stress of winter can leave
> them in a weakened condition, he said, and spawning puts additional stress
> on them. When the nearshore water temperature reaches 55-60 degrees
> Fahrenheit and the alewives move from deep water to mouths of streams and
> rivers to spawn, they are then exposed to the added stress of relatively
> rapid changes in water temperature.  A temperature change of as little as
> 10 degrees over a 24-hour period can be too much for them, he said.
> 
> "If we get a gentle warming with no sudden temperature drops, we may still
> see a die-off but not the huge numbers we saw last year," Moy said.  "But
> if we get a nice warm-up to spawning temperatures and then a change in
> weather - such as prolonged strong westerly winds that cause an upwelling
> of cold water along the coast - we'll probably see lots of dead fish on
> the beaches again."
> 
> Windrows of dead alewives piled up on Wisconsin's Lake Michigan shores in
> June 1999 after two fatally steep drops in near-shore water temperature
> caught the fish as they congregated in shallow waters to spawn and
> easterly winds washed millions of the dead fish onto Wisconsin beaches.
> 
> "I'm tracking daily nearshore water temperatures via the NOAA Great Lakes
> Environmental Research Laboratory's Coastwatch Web site
> (http://coastwatch.glerl.noaa.gov/), which provides lake surface
> temperature data from NOAA weather satellites," Moy said. "I'll be
> graphing daily water temperatures off Milwaukee, Manitowoc, Sheboygan,
> Kewaunee and Algoma on my UW Sea Grant Fisheries Advisory Services Web
> site (www.seagrant.wisc.edu/advisory/fisheries) -  I call it the 'alewife
> death watch' page
> (http://www.seagrant.wisc.edu/advisory/fisheries/alewife_death_watch_2000.
> htm)."
> 
> # # # #
> 
> Created in 1966, Sea Grant is a national network of 29 university-based
> programs of research, outreach and education dedicated to the protection
> and sustainable use of the United States' coastal, ocean and Great Lakes
> resources.  The National Sea Grant Network is a partnership of
> participating coastal states, private industry and the National Sea Grant
> College Program, National Oceanic & Atmospheric Administration, U.S.
> Department of Commerce.
> 
> 
> POSTED BY:
> Stephen Wittman
> Assistant Director for Communications
> University of Wisconsin Sea Grant Institute
> PHONE (608) 263-5371* FAX (608) 262-0591
> ****************************************************
> 
> 
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