SoundHAB: Incipient Harmful Bloom(s)

[Jack Rensel]

Conditions and timing are ideal for a Heterosigma akashiwo bloom in Puget
Sound.  

 

Some discrete areas of Heterosigma concentrations and other species have
been noticed in the past few days in North Puget Sound and possibly other
areas too.   Fish culturists are on alert and gathering more information at
this time.    

 

Presently tidal exchange is large which in the past has limited bloom
initiation.  However, next week smaller-range tides may coincide high
volumes of snow pack riverine runoff and calm-warm weather in this late June
and early July time period.   Over the past 19 years, these conditions have
often led to a fish-killing bloom of H. akashiwo.   It is impossible to
predict with great accuracy, but our conceptual model of bloom development
indicates that bloom conditions seem to be aligning.   Large-scale blooms of
this species have been known to cover entire basins of Puget Sound and cause
the death of both farmed and wild fish and probably other organisms too. 

 

Please report your observations of blooms, cell counts or other related
information to the more than 90 scientists and managers who subscribe to
this list serve.   

 

This year we ask that you also observe closely for the occurrence of large
numbers of Alexandrium catenella dinoflagellates (that cause paralytic
shellfish poisoning).   In 2006 a major Heterosigma bloom was preceded by a
large bloom of A. catenella and subsequently toxin levels reach very high
proportions.  This information may assist the Washington State Dept. of
Health in their efforts to manage the safety of wild or cultured shellfish
stocks.  Some concentrations of these cells have already been noted in the
past few days. 

 

Thank  you for your participation,

 

Jack Rensel

 

J.E. Jack Rensel Ph.D.

Rensel Associates Aquatic Sciences

4209 234th Street N.E. 

Arlington WA 98223 USA

360-435-3285

cell: 360-631-6538

jackrensel at att.net

www.AquaModel.org

 

 

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