A new study illustrates that increasing temperatures are resulting in a “growing diversity” of Vibrio bacteria in the sea around the United Kingdom (UK).
Native oysters at Chichester Harbor. Image Credit: Dr Luke Helmer.
The study headed by the University of Exeter discovered two Vibrio species — Vibrio jasicida and Vibrio rotiferianus — that have never previously been recorded in the UK waters before.
These species have the potential to harm sea creatures like shellfish, but the rising range of Vibrio species also increases problems for human health.
Few Vibrio bacteria can result in gastroenteritis while eating raw or undercooked shellfish and can also cause skin infections.
The scientists state that the spread of Vibrio species has led to a “worldwide surge” of Vibriosis infections in aquatic animals and humans.
Vibrio species can often be found in UK waters in summer, when temperatures are more favorable for them. With sea-surface temperatures rising due to climate change, Vibrio activity in the waters is more common, and the diversity of Vibrio species is now increasing.
Dr. Sariqa Wagley, University of Exeter
The study utilized Met Office data to determine locations where summer sea-surface temperatures were favorable for Vibrio bacteria (depending on the average number of days annually warmer compared to 18 °C).
Furthermore, scientists examined shellfish samples from four sites utilized by the shellfish industry — Osea Island, Chichester Harbor, Lyme Bay and Whitstable Bay.
We found Vibrio parahaemolyticus — the leading cause of seafood-borne gastroenteritis worldwide — at Chichester Harbor. Vibrio alginolyticus, which can also cause illness in humans, was identified at three of the sites that had sea-surface temperatures above 18 °C (Chichester Harbor, Osea Island and Whitstable Bay).
Dr. Sariqa Wagley, University of Exeter
Wagley continued, “It is important to note that thorough cooking kills harmful Vibrio bacteria in seafood. However, increasing abundance and diversity of Vibrio bacteria creates health risks not only for people eating seafood, but for those using the sea for recreation purposes — either due to swallowing infected seawater or from the bacteria entering exposed wounds or cuts.”
Wagley added, “Vibrio bacteria are also a threat to a variety of marine species including shellfish themselves. Disease costs the global aquaculture industry £6 billion a year, and this burden of disease can be devastating.”
“We have not seen mass mortality of shellfish due to Vibrio bacteria here in the UK yet, but this has occurred elsewhere — including in France and Australia. Our findings support the hypothesis that Vibrio-associated diseases are increasing and are influenced by the rise in l sea-surface temperature. We need to monitor this situation closely, to protect human health, marine biodiversity, and the seafood industry,” stated Wagley.
It is important to monitor the impact of increasing sea surface temperature on potential shellfish pathogens, not just for human health and safety, but also to understand the resilience of our coastal species and habitats to climate change.
Dr. Joanne Preston, University of Portsmouth
Dr. Luke Helmer, from the Blue Marine Foundation and the University of Portsmouth, added: “The impacts of climate change on the marine environment are likely to be widespread. Understanding how these changes will affect ecologically and commercially important species and the people that rely on them will be crucial moving forward, in order to mitigate against them.”
The study was financially supported by Biotechnology and Biological Sciences Research Council (BBSRC) and was assisted by Chichester and Havant Council and Sussex Inshore Fisheries and Conservation Authority.
Journal Reference:
Harrison, J., et al. (2021) The increased prevalence of Vibrio species and the first reporting of Vibrio jasicida and Vibrio rotiferianus at UK shellfish sites. Water Research. doi.org/10.1016/j.watres.2021.117942.