OBSERVATION:
Every summer for 21 years, I have the pleasure of visiting family right on Melmerby (Merb.)Beach, Nova Scotia, on the Northumberland strait (south part of the Gulf of St. Lawrence). It used to be that in early July there was no way we could go swimming in the ocean for about 2 weeks at the Merb., due to the amount of jellyfish. I remember one particular summer 7 years ago, thousands washed up on the beach, and thousands more in the water. In the last 5 years and in particular the last 2 summers we have not encountered many jellies at all. One day last July on my 2 hour walk up and down the beach I came across a jellyfish, right off the bat, I thought to myself, “it’s too bad, the kids will be disappointed to not be able to go in the water”, but to my surprise after walking for 2 hours I could count on 2 hands the amount of jellies spotted, it concerned me and I started to wonder why so few jellies have made it into shore compared to the past.
SIGNIFICANCE:
Jellyfish are a category of gelatinous zooplankton, with soft transparent bodies and they spend much of their lives drifting in water. Zooplankton float and live in the upper ocean so to have enough sunlight to support phytoplankton. Jellyfish eat phytoplankton (WHO, 2015). Jellyfish are weak swimmers, swim with the currents and are an important part of marine food chain as well as a major source of oxygen for the planet. “Zooplankton are a crucial link between phytoplankton and larger open-ocean animals”, (WHO, 2015) like fish and whales.
The unusual low number of jellyfish being washed ashore on Melmerby beach is attributed to slow currents, which jellyfish ride in on, from warmer water (CBC, 2012). Maybe the jellyfish wash up earlier in the year? Warming water is suspected to cause swarms of jellies in the ocean which has additional impacts on sea life. Climate change and warm water trends in the Northumberland strait may lead to more tropical fish species, and an increase in lobster mortality seen in the long term (CBC, 2012), not to mention how warmer water will affect seasonal timing of phytoplankton and zooplankton growth in turn impacting the fish and whale population (WHO, 2015).
CONSULT:
Marlon Lewis: marlon.lewis@dal.ca (Phytoplankton, bio-optical oceanography, upper ocean physics
Marlon indicated that "many have observed and commented on this." He to referenced the article that I found: See http://www.cbc.ca/beta/news/canada/nova-scotia/missing-jellyfish-unusual-says-marine-scientist-1.1273324
He mentioned that he "still sees comb jellies ( coelenterates) but not the moon jellies or lion's manes that used to be so dominant."
Marlon noted that, "The ocean is measurably warmer, more acidic, and increasingly dropping oxygen levels. There are fewer phytoplankton and fewer large fish. Climate change is ocean change."
RESOURCES:
Woods Hole Oceanographic Institution. (2015). Jellyfish & Other Zooplankton
CBC NEWS. (Aug., 2012). Missing jellyfish unusual says marine scientist
Images
Melmerby beach image
