||summer, but not a dominant organism.
||most frequently observed in Maryland's Coastal Bays, occasionally in
Chesapeake Bay tributaries with moderate salinity.
||Heterosigma akashiwo was identified in Middle River of
Chesapeake Bay during June 2002. Heterosigma is a bi-flagellated,
single celled, golden brown alga in the family Raphidophyceae. In the
United States it has been found on both coasts (Hargraves and Maranda
2002) and is considered the causative organism involved in fish farm
kills in Washington State on the west coast. Net-penned fish deaths
related to Heterosigma blooms have been particularly prominent in
the northeast Pacific, notably around Japan. Predictability of blooms
has been most related to temperature (warmer season waters >15 degrees
C) and moderate salinity (approximately 15 ppt) in the coastal zone (Li
and Smayda 2000, Connell and Jacobs 1997). Blooms have been observed to
persist as long as stable water stratification persists in the warmer
months. An unidentified ichtyotoxin (i.e., fish killing toxin) has been
speculated as the causative agent in the net pen fish kills. There are
no documented effects to humans from such blooms. No fish or human
health effects have been associated with this species in Maryland
||Connell, L. and M. Jacobs 1997. Anatomy of a Bloom: Heterosigma
akashiwo in Puget Sound 1997.
Hargraves and Maranda 2002. Potentially toxic or harmful microalgae from
the northeast coast. Northeastern Naturalist. 9(1): 81-120.
Li, Y. and T.D. Smayda. 2000. Heterosigma akashiwo (Raphidophyceae): On
prediction of the week of bloom initiation and maximum during the
pulse of its bimodal bloom cycle in Narragansett Bay. Plankton Biol.