Association of an unusual marine mammal mortality event with pseudo-nitzschia SPP. blooms ALONG the southern California coastline

Gretel Torres De La Riva, Christine K Johnson, Frances M D Gulland, Gregg W. Langlois, John E. Heyning, Teri K. Rowles, Jonna A Mazet

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


During 2002, 2,239 marine mammals stranded in southern California. This unusual marine mammal stranding event was clustered from April to June and consisted primarily of California sea lions (Zalophus californianus) and long-beaked common dolphins {Delphinus capensis) with severe neurologic signs. Intoxication with domoic acid (DA), a marine neurotoxin produced during seasonal blooms of Pseudo-nitzschia spp., was suspected. Definitively linking harmful algal blooms to large-scale marine mammal mortalities presents a substantial challenge, as does determining the geographic extent, species composition, and potential population impacts of marine mammal die-offs. For this reason, time series cross-correlation analysis was performed to test the temporal correlations of Pseudo-nitzschia blooms with standings occurring along the southern California coastline. Temporal correlations were identified between strandings and blooms for California sea lions, long-beaked common dolphins, and short-beaked common dolphins (Delphinus delphis). Similar correlations were identified for bottlenose dolphins (Tursiops truncatus) and gray whales (Eschrichtius robustus), but small sample sizes for these species made associations more speculative. The timing of the blooms and strandings of marine mammals suggested that both inshore and offshore foraging species were affected and that marine biotoxin programs should include offshore monitoring sites. In addition, California sea lionstrandings appear to be a very sensitive indicator of DA in the marine environment, and their monitoring should be included in public health surveillance plans.

Original languageEnglish (US)
Pages (from-to)109-121
Number of pages13
JournalJournal of Wildlife Diseases
Issue number1
StatePublished - Jan 2009


  • California sea lion
  • Common dolphin
  • Domoic acid toxicity
  • Harmful algal blooms
  • Marine mammal strandings
  • Pseudo-nitzschia spp

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology


Dive into the research topics of 'Association of an unusual marine mammal mortality event with pseudo-nitzschia SPP. blooms ALONG the southern California coastline'. Together they form a unique fingerprint.

Cite this