Since 1991, several outbreaks of
toxic Euglena (Fig. 3) have occurred
in North Carolina hybrid striped
bass (Morone saxatilis x M. chrysops)
production ponds, causing the loss
of more than 20,000 pounds of fish
Relatively recent research has confirmed
that Euglena species produce
an ichthyotoxin in freshwater aquaculture
(Zimba et al., 2004). The hybrid
striped bass mortalities in North
Carolina were caused by E. sanguinea,
a widely distributed species
in many shallow, relatively calm,
eutrophic freshwater systems. This
species also killed laboratory-reared
channel catfish, tilapia (Oreochromis
niloticus) and striped bass. In confirmatory
studies, Zimba et al. (2004)
noted that cultures of Euglena granulata
(UTEX LB2345) caused similar
mortalities and symptoms in channel
catfish and sheepshead minnows
(Cyprinodon variegatus).