Could researching Vibrio bacterial infections in pet seahorses help further understanding of tropical coral reef bleaching events linked to global warming? It might be a stretch, but the recent findings of researchers at the Hollings Marine Laboratory in Charleston, South Carolina reported by CORAL magazine (Jan/Feb 2010) were eerily familiar to many seahorse keepers. Seahorses and stony corals have something terrible in common – deadly bacterial infections with surprising similarities.

For years seahorse keepers have noticed a correlation between high temperatures and Vibrio bacterial infections in their pets. In the book Working Notes – A Guide to Seahorse Diseases pathologist Martin Belli M.D. notes that up to 70% of seahorses test positive for Vibrio, but only about 30% actually die from it. Healthy seahorses testing positive for Vibrio are likely to be asymptomatic carriers. He also writes that strains of Vibrio found to affect seahorses did not grow well in a lab at temperatures lower than 64°F. Seahorse.org members have long advocated seahorse aquarium temperatures below 75°F because Vibrio becomes more aggressive and virulent at higher temperatures.

Researchers at the Hollings Marine Laboratory have discovered a temperature dependent trait in the bacteria Vibrio coralliilyticus, which may be responsible for coral bleaching events. Similar to the Vibrio bacterium found in seahorses, Vibrio coralliilyticus does not normally cause disease in healthy, lab raised Pocillopora damicornis coral specimens at a temperature of 75°F, but becomes pathogenic at higher temperatures. Temperatures above 80°F increase the acceleration and severity of the infection.

by Felicia McCaulley

Felicia has been keeping aquariums since the early 90s and has a keen interest in taxonomy, aquaculture, and seahorses. she is the former Liveaquaria Diver's Den photographer and now works for Philadelphia area's largest aquarium specialty store The Hidden Reef.