The toxic effects of three dinoflagellate species from the genusKareniaon invertebrate larvae and finfish

Differential inimical effects of Alexandrium spp. and Karenia spp. on cleavage, hatching, and two larval stages of Japanese pearl oyster Pinctada fucata martensii

“…Pacific oyster, Japanese pearl oyster, Japanese abalone, and horned turban) in the wild (Oda, 1935), showed no acute ichtyotoxicity and affected only H. iris larvae. Brevetoxin-producer K. brevis had no effects on any of the invertebrate larvae, whereas K. brevisulcata was highly toxic to larvae of P. canaliculus, H. iris, and sea urchin, toxic to larvae of C. gigas and sea slugs, but did not affect larvae of shrimp (Shi et al, 2012). Several allelochemicals and toxic compounds have been isolated from Karenia spp.…”

“…In a previous study, trochophores of Crassostrea gigas exposed to K. mikimotoi at 3 Â 10 4 cells ml À1 died at as much as 99-100% within 8-10 h (Matsuyama et al, 2001). In a recent study, Shi et al (2012) exposed juvenile larvae of Chinook salmon (Oncorhynchus tshawytscha), snapper (Pagrus auratus), sea slug, sea urchin, brine shrimp, Greenshell TM mussel (Perna canaliculus), Pacific oyster (C. gigas), and New Zealand abalone (Haliotis iris) to K. mikimotoi (negative for PbTx production), Karenia brevis (producer of PbTxs), and Karenia brevisulcata (producer of brevisulcatic acid BSXs, and K. brevisulcata toxins KBTs). Whereas K. brevis and K. brevisulcata were toxic to fish, K. mikimotoi, long-known to cause mortalities of fish-and shellfish (e.g.…”

Novel toxins produced by the dinoflagellate Karenia brevisulcata

“…Further NMR data for BSXs is being obtained at 243 K to reduce conformational exchange effects and enable complete structural elucidation of the molecules. In vivo bioassay studies of the toxicity of cultures using three species of Karenia with fish and invertebrates have confirmed field observations on the very high ecotoxic risks posed by blooms of K. brevisulcata (Shi et al, 2011). More detailed studies are required, using isolated toxins and mixtures, to better understand the mode of action of KBTs, potential synergism with BSXs, and risks to mammals from dietary or aerosol exposures.…”

“…Continuous cultures of K. brevisulcata with pH control at 8.3 gave higher proportions of BSX-4 and BSX-5 which are proposed to be the parent toxins produced by the cells (Beuzenberg et al, in press). However, the ring opened analogues still predominated which is not the case with cultures of K. brevis where the proportion of ringopened brevetoxins in young cultures generally did not exceed 30% (Abraham et al, 2006;Roth et al, 2007;Shi et al, 2011). K. brevisulcata cells may be more fragile or leaky enabling a higher proportion of parent toxins to enter the medium and undergo hydrolysis.…”

Potential impacts of blooms of the toxic dinoflagellate Karenia brevis on the growth, survival and juvenile recruitment of the non-native green mussel Perna viridis in southeastern United States

“…Previous work has shown P. viridis to exhibit reduced clearance rates when exposed to toxic dinoflagellates, including K. brevis (Li et al 2002;May et al 2010;Leverone et al 2007), which may affect growth in the long term due to a reduction in food intake and energy acquisition. During K. brevis blooms this toxic dinoflagellate often dominates the phytoplankton population, leaving a harmful food source which can cause tissue damage, especially in the gills and digestive tract, leading to increased avoidance behavior through valve closure and reduced feeding efficiency (Shumway & Cucci 1987;Shi et al 2012). Reduction in feeding leads to a disruption in energy assimilation that, in turn, may limit growth in response to increased cost of somatic maintenance as energy allocation to maintenance and tissue repair will take priority over growth (Bayne and Newell 1983).…”