| dc.contributor.author | Lawrence, Janice Elaine. | en_US |
| dc.date.accessioned | 2014-10-21T12:34:12Z | |
| dc.date.available | 1999 | |
| dc.date.issued | 1999 | en_US |
| dc.identifier.other | AAINQ49273 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55653 | |
| dc.description | Diarrhetic shellfish poisoning (DSP) is commonly associated with the occurrence of planktonic dinoflagellates from the genus Dinophysis . In some regions shellfish toxicity and the abundance of Dinophysis are not well correlated, and it is suspected that dinoflagellates from the genus Prorocentrum may also be responsible for the accumulation of toxins. These organisms however, are epibenthic/epiphytic and are not normally found in the water column where shellfish in suspension culture could ingest them. The goal of my thesis was to examine the role of these dinoflagellates in the accumulation of DSP toxins in shellfish. This research was primarily conducted at an aquaculture lease in Mahone Bay, where mussels are sporadically found to contain DSP toxins. | en_US |
| dc.description | I surveyed the aquaculture lease for two summers and regularly observed populations of Dinophysis in the water column. Prorocentrum lima was also found living epiphytically on filamentous macroalgae that regularly foul mussels grown in the region. While P. lima was not seen in significant numbers in the water column, it was consistently found on the macroalgae and remnants of P. lima cells were regularly observed within the digestive system of the mussels. I developed a technique for detecting DSP toxins within individual dinoflagellate cells, and showed that Dinophysis spp. cells collected from Mahone Bay did not contain toxins, while P. lima cells did. I have shown that the detection antibody used in this method effectively identifies all compounds associated with DSP, and thus provides a robust method for detecting toxicity. | en_US |
| dc.description | I examined the role of active mussel culture on the colonization and growth of the toxic dinoflagellate and the host, by deploying mussel culture socks containing either live mussels or shells. After nine weeks, the biomass of macroalgae was significantly higher on the live mussels, while the total number of P. lima cells in either treatment was the same. This demonstrates that although the microenvironment created by mussel culture enhances the growth of some algae, it does not stimulate the colonization or growth of P. lima. I then used a recirculating seawater flume to examine the hydrodynamics required to erode P. lima from its host substrate. I observed a significant increase in the proportion of eroded cells with increased current speeds. This suggests that P. lima will be found in the water column following turbulent events such as storms, which cause increased wave oscillations and wind-induced current speeds. | en_US |
| dc.description | The general conclusion of my thesis is that P. lima is likely to be responsible for the accumulation of DSP toxins in Mahone Bay, NS. This information has provided significant insight into the cause of DSP in other regions, and will aid the shellfish aquaculture industry to assess the potential for DSP at aquaculture leases, and monitor, predict, and manage this shellfish poisoning. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1999. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Health Sciences, Toxicology. | en_US |
| dc.subject | Biology, Microbiology. | en_US |
| dc.subject | Biology, Oceanography. | en_US |
| dc.title | Population dynamics and toxicity of the epiphytic dinoflagellate Prorocentrum lima in a shallow coastal embayment: Implications for shellfish aquaculture. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
