Sublethal effects of the toxic alga Heterosigma akashiwo on the southeastern oyster (Crassostrea virginica)

Keppler, Charles J.; Hoguet, Jennifer; Smith, Kristin; Ringwood, Amy H.; Lewitus, Alan J.

doi:10.1016/j.hal.2004.05.002

Cited by 55 publications

(51 citation statements)

References 34 publications

(33 reference statements)

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“…Heterosigma akashiwo was the most common and abundant potentially harmful algal species noted during this study, with the duration and intensity of its blooms being the most evident differences among sites in the phytoplankton community composition. This raphidophyte damages the digestive system in shellfish (Keppler et al 2005), and pHAB biomass was indeed positively correlated with SI oyster mortality. Diatoms were also highly correlated with instant oyster mortality at SI, although they only represented < 6% of the total biomass at this site.…”

Section: General Phytoplanktonmentioning

confidence: 88%

“…Harmful algal blooms (HABs) can cause shellfish mortalities by means of oxygen depletion and/or tox in production (Shum way et al 1990, Lands berg 2002. HABs can also re duce shellfish growth rates (Alexander et al 2006) and filtration efficiencies (Gainey & Shumway 1988, Cassis & Taylor 2006, as well as damaging their digestive systems (Keppler et al 2005, Galimany et al 2008). Oysters may succumb to opportunistic viral and bacterial infections during or after periods of heightened environmental and/ or physiological stress (Fried man et al 1991, Cheney et al 2000, Burge et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Effects of the environment and culture depth on growth and mortality in juvenile Pacific oysters in the Strait of Georgia, British Columbia

Cassis¹,

Pearce²,

Maldonado³

2011

Aquacult. Environ. Interact.

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The effects of environmental variables, culture depth, and phytoplankton abundance and composition on juvenile Pacific oyster Crassostrea gigas growth and mortality were studied between June and October of 2008 at 4 sites in the Strait of Georgia, British Columbia, Canada. In addition, the effects of temperature-triggered depth manipulation on growth and mortality of oysters were examined in order to assess potential control measures for mitigating high summer mortalities associated with high temperature, harmful algal blooms (HABs), and other environmental stressors. Control oysters were held at constant depths of 3, 10, and 15 m, while experimental oysters were kept at 3 m depth and lowered to 10 or 15 m when the surface water temperature reached 14, 16, or 18°C. Site and Depth significantly affected the growth and mortality of control oysters. At the site with the best growth, cumulative mortality was low (range: 6.4 to 19%) and negatively correlated with temperature and positively with transparency. At the high-mortality site (range: 64 to 98%), mortality was positively correlated with temperature, chlorophyll concentration, and the biomass of diatoms and potentially harmful algae. Cumulative mortality was generally higher at 3 m than at 15 m depth. Significantly larger oyster volume was obtained with the oyster controls at 3 m than with those held at 10 or 15 m at most sites. Temperature-trigger treatments did not significantly affect oyster volume or cumulative mortality, and oysters moved to 10 and 15 m had final volumes similar to the 10 and 15 m controls, independent of trigger temperature. Oyster growers could select their sites for maximal growth and minimal mortality based on temperature profile, freshwater input, and phytoplankton abundance and composition.

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Section: General Phytoplanktonmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Effects of the environment and culture depth on growth and mortality in juvenile Pacific oysters in the Strait of Georgia, British Columbia

Cassis¹,

Pearce²,

Maldonado³

2011

Aquacult. Environ. Interact.

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“…28,29) Lysosomal destabilization is therefore considered to be a well-established and sensitive biomarker of cellular stress in shellfish, 30) for example, an elevated lysosomal destabilization rate has been demonstrated in oysters exposed to the raphidophycean flagellate, Heterosigma akashiwo. 22) Figure 3 shows a gradual increase in the lysosomal destabilization rate observed in the clams exposed to the live cell suspension of H. circularisquama, together with the exposure time, whereas C. marina and H. triquetra caused no significant increase in lysosomal destabilization. The disrupted cell suspension and culture supernatant prepared from each of these flagellates had no significant effect.…”

mentioning

confidence: 98%

“…A neutral red (NR) lysosomal retention assay of the hemocytes was conducted by following the method previously described. 21,22) In brief, hemocytes were withdrawn from a clam in physiological saline. The cell suspension was mixed with a neutral red solution and then incubated in the dark at room temperature for 1 h. The stained cells were examined under an optical microscope to evaluate the NR A and B, Toxic effects on short-necked clams.…”

mentioning

confidence: 99%

Comparative Study on the Toxic Effects of Red Tide FlagellatesHeterocapsa circularisquamaandChattonella marinaon the Short-Necked Clam (Ruditapes philippinarum)

Kim

Choi

Hong

et al. 2011

Bioscience, Biotechnology, and Biochemistry

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“…These blooms can be ichthyotoxic, causing mortality in both caged and naturally occurring fish populations (Honjo 1993;Khan et al 1997). Sublethal effects, including the destabilization of cellular defense mechanisms in oysters (Keppler et al 2005) and altered respiratory activity of mammalian cells (Twiner et al 2004) have been observed upon exposure to H. akashiwo. Although there is no consensus on the mode of toxicity for H. akashiwo, possible modes include the production of reactive oxygen species (Twiner et al 2001), mucus (Nakamura et al 1998), and neurotoxins (Khan et al 1997).…”

mentioning

confidence: 99%

Avoidance, movement, and mortality: The interactions between a protistan grazer and Heterosigma akashiwo, a harmful algal bloom species

Harvey

Menden‐Deuer

2011

Limnology & Oceanography

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A reduction in predator-induced grazing pressure may be a mechanism that facilitates the formation and persistence of harmful algal blooms. Here, the hypothesis was tested that the heterotrophic ciliate Favella ehrenbergii would use avoidance behaviors to reduce encounters with the toxic bloom-forming alga, Heterosigma akashiwo. Using video and image-analysis, population distributions and three-dimensional movements of F. ehrenbergii and H. akashiwo were quantified in triplicate, hourly for 11 h, at nine horizons in a 1-liter experimental column. The salinity structure in the column was manipulated to include a halocline, resulting in layer formation by H. akashiwo. The ciliate's vertical distributions were restricted to high-salinity waters below the halocline, while H. akashiwo was broadly halo-tolerant and could occupy the whole water column. When observed together, F. ehrenbergii did not avoid layers of H. akashiwo. In the presence of H. akashiwo, F. ehrenbergii mortality rates were higher than in either no prey or beneficial prey controls. Swimming behaviors of F. ehrenbergii were erratic, in response to H. akashiwo, compared to aggregative movements in response to beneficial prey, indicating either a behavioral response or the effect of H. akashiwo toxicity on the ciliate. The inability of F. ehrenbergii to avoid H. akashiwo enhanced predator mortality and may contribute to the survival of the harmful algal bloom species, ultimately promoting the formation of H. akashiwo harmful algal blooms.

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Sublethal effects of the toxic alga Heterosigma akashiwo on the southeastern oyster (Crassostrea virginica)

Cited by 55 publications

References 34 publications

Effects of the environment and culture depth on growth and mortality in juvenile Pacific oysters in the Strait of Georgia, British Columbia

Effects of the environment and culture depth on growth and mortality in juvenile Pacific oysters in the Strait of Georgia, British Columbia

Comparative Study on the Toxic Effects of Red Tide FlagellatesHeterocapsa circularisquamaandChattonella marinaon the Short-Necked Clam (Ruditapes philippinarum)

Avoidance, movement, and mortality: The interactions between a protistan grazer and Heterosigma akashiwo, a harmful algal bloom species

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