Roy L Hales/ Cortes Currents - Around 30 people trekked through the spit into Mansons Lagoon, during the July 12 ‘Gumbooting the Lagoon.’ While Jane Newman explained the site’s human history, marine biologist Deb Cowper and FOCI’s Autumn Barret Morgan introduced everyone to intertidal life forms. One of the many topics that arose was the loss of marine life.
After the tour, Cortes Currents asked Cowper further explanations.
“I haven't come and done any firsthand studies or seen any data sets that people have been monitoring over time. I can't give a definitive answer that such and such a population is in decline or what the trends are, “ she began.
Then Cowper proceeded to make some personal observations. The parts of the shortline shorelineusually covered by water looked pretty healthy, but there appeared to be less biodiversity and numbers in the more exposed upper region. This appeared to also be true in the inner lagoon.
“There's probably no one smoking gun on here. You could talk about impacts of people trampling or collecting. You could talk about shifting climate, that’s probably a really big one. You could point to a number of different things and without proper studies, it would be kind of wrong on me to try and figure out exactly what was the cause,” explained Cowper.
Tokin Wakefield has observed the lagoons crab population virtually disappear during the 40 years she has lived by the edge of the lagoon. She and Cowper discussed the species during the gumboot tour.
“They used to be everywhere And now we can hardly find them in the inner lagoon,” said Wakefield.
Cowper also noted that, while it could a coincidental, she saw a much higher proportion of sea stars with wasting disease.
“They seemed to be more on the rebound before the heat dome. This year I was surprised that probably a quarter of the individuals that we did see were impacted, which is concerning that it seems to be happening again,” she said.
While some species are recovering better than others, Cowper said she has not seen as much biodiversity in the lagoon since last year’s heat dome.
While thousands of barnacles perished in the heat dome, there is also “lots of the spat of the little babies on the rocks.” So she expects to see a full recovery providing there isn’t another heat dome.
The number of sea stars is so reduced that Cowper suggested they need imported plankton born replacements.
“I'm quite worried about the sand dollars though, I really expected to see more this year. Last year, I saw an absolutely beautiful crop of sand dollars before the heat dome. I saw the devastation immediately afterwards, but it really doesn't seem to have rebounded that I can just see from our tour today. That's a bit of a concern.”
She added, “If we've got a lot of those heat dome type episodes as climate change progresses, I think we might be in trouble and see lots of shifts in the ecosystem.”
Providing heat domes are once in a lifetime events, or not particularly frequent, she expects the Marine life to rebound.
“What we're all very concerned about, and I think what we're witnessing unfold, is that climate change is going to bring these significant changes at a far greater rate and the frequency of those is going to ultimately impact species attempts to recover,”
“Different species on the intertidal zone have a different range of tolerance. Those who are really adapted and do well, or live in a habitat like those gaper clams fairly well protected and deep where it's cool, they will continue to do reasonably well. But those species that are not as tough to do with changing temperatures in particular, salinity perhaps, and so on, they will quite likely shift in terms of their distribution. They might well lose numbers and potentially lose their foothold on this area.”
