Non-native jellyfish wipe out salmon fishery in Northern Ireland – another warning sign?


Over the Thanksgiving holiday, a massive bloom of “mauve stinger” jellyfish, in a dense pack covering 10 square miles 35 feet deep, thousands of miles north of their preferred ocean habitat, feasted on about a half a million pounds of gourmet, organic salmon being raised in pens off the coast of northern Ireland and slated for market during the upcoming holiday season.  All indications are that climate change played a key role in the fatal intrusion.  The incident raises important questions for the US climate science programs and our overall level of climate change preparedness.

[Returning to posting after a break to deal with other pressing matters.]

The Climate Science Watch research team found a short newspaper article on this incident really striking and looked into the possible connection with impacts of anthropogenic climate change. A report:

On November 21 the Washington Post reported that an invasion of “mauve stinger” jellyfish, Pelagia nocticula, in a dense pack of about 10 square miles and 35 feet deep, killed about 120,000 salmon in a fishery off the coast of Ireland, north of Belfast. 
This particular species of jellyfish, increasingly common in the warmer waters of the Mediterranean Sea but until now rarely, if ever, found in the higher latitudes of British and Irish waters, has migrated northward and reproduced in vast numbers.  The accounts of this incident attribute this pelagic anomaly to climate change and strong ocean currents in the Atlantic that swept the jellyfish to waters near the shore.  There have also been accounts of jellyfish being transported long distances on ocean-faring vessels; once introduced, they reproduce asexually and tend to multiply rapidly. Diminishing populations of sea turtles and over-fishing resulting in decreased natural predators can also allow jellyfish populations to grow unchecked.

This anomaly of nature serves as yet another sign that global changes are continuing to occur more rapidly and in ways not entirely predicted or anticipated.  Although the IPCC’s most recent Working Group II report on climate-related impacts released earlier this year does not specifically mention jellyfish encroachment as a potential problem, it does warn that pelagic fish populations are likely to migrate north as ocean waters continue to warm. 

The jellyfish attack wiped out the entire stock of the Northern Salmon Company; more than 200 metric tons (about 440,000 pounds) of fish worth £1m or US $2 million was lost overnight, according to numerous reports in the European press.  Northern Salmon supplies high quality, organic salmon to top restaurants and hotels throughout Europe and the US.  See article here.

John Russell, who had just started as managing director three days before, was understandably taken aback.  “It was unprecedented, absolutely amazing. The sea was red with these jellyfish and there was nothing we could do about it, absolutely nothing,” he lamented.  The company’s dozen workers tried in vain to prevent disaster, but their boats were unable to penetrate the mass of jellyfish to rescue the salmon.  All were killed from a combination of stings, stress, and lack of oxygen.  Ireland’s Chief Fisheries Officer with Ireland’s Department of Agriculture said there was nothing he believed Northern Salmon or any fishery could have done or could do to prevent this or future attacks.  See article here.

The incident is another clear example of local, severe economic loss as a result of a “natural disaster”—and to the extent that the climatic changes helped to bring this about, Northern Salmon joins the global warming victim list. 

“In 30 years I’ve never seen anything like it. The sea was red with these jellyfish.  It’s a disaster for this company. We’ve taken a huge financial hit,”  Russell reported.  It will likely take a good two years for his company to recover; his employees will likely lose their jobs.  Ireland’s agriculture minister, Michelle Gildernew, indicated there was no public source of funding to compensate Northern Salmon, but that she would take the matter up with the relevant authorities See article here

It is thought that since jellyfish respond rapidly to changing environmental conditions, they can act as sentinels to identify future changes in marine ecosystems.  While the scientific body of evidence on this issue is still being developed, scientists in northern Europe and elsewhere are studying the effect of climate change on jellyfish populations and drawing some important conclusions.  For example, according to Dr. Martin Attrill, a professor at the University of Plymouth’s Marine Institute in the UK: 

“Looking ahead over the next 50 to 100 years, all climate projections expect the North Sea to become warmer, so jellyfish will become more and more common in our waters. Increasing occurrence of jellyfish has been considered a potential problem for the world’s seas for two main reasons. Firstly, jellyfish are major predators of animals in the plankton, including young larval fish of important commercial fisheries; increasing jellyfish feeding may therefore reduce recruitment to North Sea fisheries, resulting in smaller stocks to exploit.…Additionally, very few other animals eat jellyfish, so a build up of jelly will not provide food for the rest of the marine ecosystem. A combination of both of these impacts means that these findings are exceptionally important as climate-related changes in jellyfish in the North Sea could dramatically change the way the system is functioning. The North Sea ecosystem may therefore change markedly over the coming years as the climate warms and the jellies take over.”  See article here.

“Data obtained since 1958 from the continuous plankton recorder show an increasing occurrence of jellyfish in the central North Sea that is positively related to the North Atlantic Oscillation (NAO) and Atlantic inflow to the northern North Sea. Since 1970, jellyfish frequency has been also significantly negatively correlated with mean annual pH, independent of NAO trends. Jellyfish frequency increased in the mid-1980s, coincident with the reported regime shift in the North Sea and tracking trends in phytoplankton color. As models produced under all climate-change scenarios indicate a move toward a positive NAO, and pH of the oceans is predicted to decrease with rising CO2, we suggest that jellyfish frequency will increase over the next 100 yr.”  (Source: Attrill, M. and Wright, J. and Edwards, M. (2007) Climate-related increases in jellyfish frequency suggest a more gelatinous future for the North Sea. Limnology and Oceanography, 52 (1). pp. 480-485. ISSN 0024-3590)

Another study:
“Jellyfish abundance is increasing in numerous marine ecosystems worldwide, perhaps as a consequence of ‘‘regime shifts’’ associated with climatic change, increasing fishing pressure, or both…..The NAO [North Atlantic Oscillation] is significantly related to sea level pressure, surface winds, wave heights, sea surface temperature, and current influx to the North Sea (Beaugrand 2003) and has the potential to influence profoundly the pelagic environment.  Jellyfish are able to respond rapidly to favorable environmental conditions, and blooms in their abundance could provide a biological indication of interannual variation in hydroclimatic conditions. Thus, it is expected that, if influential, NAO-related effects on the ecosystem could rapidly become evident in jellyfish populations. Using data on the abundance of medusae of Aurelia aurita, Cyanea lamarckii, and Cyanea capillata from the North Sea, we explore here the possibility that jellyfish populations respond to climatic variation as quantified by the NAOI [North Atlantic Oscillation Index].  (Source:  Lynam, C.P.; S.J. Jay, A.S. Brierley.  2004.  Interannual variability in abundance of North Sea jellyfish and links to the North Atlantic Oscillation; Limnol. Oceanogr.,  49(3), 637–643.

And another:
“Jellyfish medusae prey on zooplankton and may impact fish recruitment both directly (top-down control) and indirectly (through competition). Abundances of Aurelia aurita, Cyanea lamarckii and Cyanea capillata medusae (Scyphozoa) in the North Sea appear to be linked to large-scale inter-annual climatic change, as quantified by the North Atlantic Oscillation Index (NAOI), the Barents Sea-Ice Index (BSII) and changes in the latitude of the Gulf Stream North Wall (GSNW). Hydroclimatic forcing may thus be an important factor influencing the abundance of gelatinous zooplankton and may modulate the scale of any ecosystem impact of jellyfish. The population responses are probably also affected by local variability in the environment manifested in intra-annual changes in temperature, salinity, current strength/direction and prey abundance.”  Source:  CP Lynam, SJ Hay, AS Brierley.  2005.  “Jellyfish abundance and climatic variation: contrasting responses in oceanographically distinct regions of the North Sea, and possible implications for fisheries.” (Journal of the Marine Biological Association of the United Kingdom; 85: 435-450)

Other fisheries are thought to be at risk.  The billions of “mauve stingers” are still on the move and other blooms are being reported.  The UK’s Marine Conservation Society (MCS) has recruited volunteers to survey the waters, and is reported to have received reports of millions of baby mauve stinger and compass jellyfish in the region, washed in by Atlantic currents. See article here

Earlier this year there were reports of a species of a giant spotted jellyfish native to Australia, Phyllorhiza punctata, invading the waters of the Gulf of Mexico and up the eastern coast of Florida and as far north as North Carolina.  See articles here and here.

On Saturday, November 17, just a couple of days after the salmon kill, UN Secretary-General Ban Ki-moon spoke at a press conference in Valencia, Spain to release the IPCC Synthesis Report.  He spoke of rapidly melting Arctic sea ice, the decimation of the Brazilian rainforest, and the ozone hole over Chile.  He said, “These scenes are as frightening as a science fiction movie. But they are even more terrifying, because they are real.”  The massive bloom of invasive “killer” jellyfish on the loose in Irish waters is a scene that could arguably be added to the sci-fi list. 

This seemingly freakish event raises some important questions: 

—-  Are jellyfish indeed good sentinels to study for improving our understanding of climate impacts on ocean ecology?  If so, should the US climate science program begin to focus more intensely on jellyfish population dynamics?
—- How are the interests of US fisheries compromised by sudden fluctuations in jellyfish populations? 
——What do we know about how other marine species will behave in a warmer climate? 
—-  What sorts of early warning systems do we have in place for such threats? 
—-  What sorts of preventive and/or protective measures are available? 
—-  How prepared is our federal government, in particular the NOAA National Marine Fisheries Service (NMFS)— should such incidents begin to occur within US waters? 
—-  How much better prepared might we be now had the National Assessment of Climate Change Impacts process – and in particular the assessment for coastal areas— been allowed to continue as mandated by the Global Change Research Act? 


And – we must ask – even in the wake of the unequivocal conclusions stated in the IPCC’s recently released Synthesis Report, how many more warning signs such as this one are needed before US leadership is willing to take decisive action to address climate change, both in terms of mitigation through CO2 and other GHG reductions and equally as important, in terms of national preparedness to deal with harmful climate change impacts and adopt needed adaptation measures? 

We wonder, how would John Russell answer that question?

This entry was posted in Assessments of Climate Impacts and Adaptation, Global Climate Disruption and Impacts. Bookmark the permalink.