title: Spatiotemporal patterns of paralytic shellfish toxins and their relationships with environmental variables in British Columbia, Canada from 2002 to 2012.
abstract: Harmful algal blooms produce paralytic shellfish toxins that accumulate in the tissues of filter feeding shellfish. Ingestion of these toxic shellfish can cause a serious and potentially fatal condition known as paralytic shellfish poisoning (PSP). The coast of British Columbia is routinely monitored for shellfish toxicity, and this study uses data from the monitoring program to identify spatiotemporal patterns in shellfish toxicity events and their relationships with environmental variables.
  
  
  
  The dinoflagellate genus Alexandrium produces the most potent paralytic shellfish toxin, saxitoxin (STX). Data on all STX measurements were obtained from 49 different shellfish monitoring sites along the coast of British Columbia for 2002-2012, and monthly toxicity events were identified. We performed hierarchical cluster analysis to group sites that had events in similar areas with similar timing. Machine learning techniques were used to model the complex relationships between toxicity events and environmental variables in each group.
  
  
  
  The Strait of Georgia and the west coast of Vancouver Island had unique toxicity regimes. Out of the seven environmental variables used, toxicity in each cluster could be described by multivariable models including monthly sea surface temperature, air temperature, sea surface salinity, freshwater discharge, upwelling, and photosynthetically active radiation. The sea surface salinity and freshwater discharge variables produced the strongest univariate models for both geographic areas.
  
  
  
  Applying these methods in coastal regions could allow for the prediction of shellfish toxicity events by environmental conditions. This has the potential to optimize biotoxin monitoring, improve public health surveillance, and engage the shellfish industry in helping to reduce the risk of PSP.
authors.affiliation: Spatial Pattern Analysis & Research Lab, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2. Electronic address: s_finnis@hotmail.com.
authors.forename: Stephen
authors.initials: S
authors.lastname: Finnis
authors.affiliation: Environmental Health Services, British Columbia Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4. Electronic address: nikolas.krstic@bccdc.ca.
authors.forename: Nikolas
authors.initials: N
authors.lastname: Krstic
authors.affiliation: Environmental Health Services, British Columbia Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4. Electronic address: lorraine.mcintyre@bccdc.ca.
authors.forename: Lorraine
authors.initials: L
authors.lastname: McIntyre
authors.affiliation: Spatial Pattern Analysis & Research Lab, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2. Electronic address: trisalyn@uvic.ca.
authors.forename: Trisalyn A
authors.initials: TA
authors.lastname: Nelson
authors.affiliation: Environmental Health Services, British Columbia Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4; School of Population and Public Health, University of British Columbia, 2206 East Mall, 3rd Floor, Vancouver, BC, Canada V6T 1Z3. Electronic address: sarah.henderson@bccdc.ca.
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Henderson
mesh_terms: D000818:Animals; D001955:British Columbia; D016000:Cluster Analysis; D004141:Dinoflagellida / Q000502:physiology*; D004777:Environment; D057097:Harmful Algal Bloom; D000069550:Machine Learning; D012530:Saxitoxin / Q000032:analysis*; D012623:Seawater / Q000032:analysis*; D012758:Shellfish
chemical_list: D012530:Saxitoxin
keywords: Biotoxin monitoring; Machine learning; Paralytic shellfish poisoning; Public health; Spatiotemporal pattern analysis