Light Trappers Dazzling Discoveries:  #1

April 16 – Day One   Hello False Creek Light Trappers!  We have now recorded our first day of this eye-opening Hakai Institute-supported project to capture the larva of the Dungeness Crab, called megalopae.

So far, 24 hours into the adventure, zero megalopae. Project leader Dr. Matt Whalen explained that this early in the Spring season, evidence of baby crabs might be scant . (That’s Matt, below, showing False Creek Light Trapper a demonstration “catch”, on April 5.)

Matt Whalen with volunteers
Matt Whalen with FCFS volunteers Ap 13, 2022

We’re one of 24 community partner organizations scattered along the coast of the Salish Sea (click here for a map of all of us, Canadian and American).  We’re still  learning how the light trap works and how to make sure it does its job – luring sea critters into it during the night when extremely bright LED lights turn on and become an irresistible attractant.  

Every other day, during daylight hours, volunteers “arm” the trap by setting a timer that will turn on the LEDs at the approximate time of sunset, and turning it off at sunrise. Once the timer  is set, thetrap is lowered in the water and “fishes” during the night, attracting an amazing number of skittering animals. 

Then, the next day, we do our jobs, retrieve everything the trap has caught (including some pretty weird wormy things, click here if you dare). But with a laser focus on identifying the Dungeness Crab toddlers, the megalopa, the “bycatch” is discarded without comment, and the Metacarcinus magister  progeny are counted, photographed,  (and weekly, measured), and the data entered into a very special smartphone app.  Then all the captives are released, unharmed.  Sometimes, Matt told us, we may find hundreds if not thousands of megalopa needing to be processed. The light trap season lasts from April 15 to Sept 1 but many years of data collection may be needed to address the biggest questions that motivate the Sentinels of Change project: Namely, does the quantity of new crab recruits each year give us an indication of how strong the fishery will be once the crabs get big enough to eat (~4 years)?

Extremely labor-intensive. Needing dedicated volunteers, all up and down the Salish Sea.  Adults and kids from big cities (like Vancouver) to  residents of small Indigenous villages (like the Swinomish Indian Tribe in Washington state, which has been instrumental in advancing scientific and Indigenous knowledge of marine ecology) .  Hauling the traps out of the water, evaluating, measuring, and entering an enormous amount of that information into a database –  it’s way too much effort for the scientists to do on their own –  and so, we “citizen scientists” get to help. It literally could not be done without all of the 24 community groups that have committed to do the work.

But why?  What is it about these young crab critters that deserves such attention?
The most obvious answer is that the Dungeness Crab is a very, very important seafood – in fact, this fishery is among the most valuable of all seafoods along the west coast of the US. .

In BC, it represents about 15% of the total value of all – ALL – fish landings. According to the BC government, the catch of salmon, halibut, cod, herring, etc. etc., was $400 million in 2018. So, getting out the calculator, 15% percent –  that’s something like $60 million.

Along the US coast, it’s a $250 million industry. A big deal.

And, another big reason for this very large, labor-intensive project is that the Dungeness has been and is an important resource for Indigenous Peoples all up and down the Salish Sea.. It’s no wonder that Indigenous Tribes such as the Swinomish in Washington state have been instrumental in promoting deep community involvement in doing the science – protecting what they say is Washington’s most important seafood resource. 

And in BC, First Nations communities have been in the forefront of expressing their concern about declining crab catches, and have negotiated with the Government of Canada a collaborative pilot program to make decisions about crab fisheries with the nations as part of its commitment to a fisheries reconciliation agreement.

And this gets us to the real issue of why so much effort is going into this intensive study of the Dungeness Crab. And the clue is encoded into the very name of Hakai’s project: “Sentinels of Change.”

So: what’s a “sentinel”? In common language, it usually refers to some person whose only job is to keep watch, like a solitary soldier or sentry posted on the front lines, watching for enemy movement.  In the scientific sense,  sentinel species are those organisms that reflect sometimes minute but potentially harmful changes in the environment.

The Dungeness Crab is such a sentinel species. It is out there, standing guard, and registering the impact of impending drastic changes to the ocean environment.  And so far, the science has revealed quite ominous changes.  And guess who is responsible. Yes, that’s right:  All of us who are .  Burning fossil fuels that release carbon dioxide.

It turns out that the oceans, upon which all life on Planet Earth depends, is a fabulously effective sponge that sucks carbon dioxide out of the atmosphere like a cosmic vacuum cleaner. You might be thinking: “Well, isn’t CO2  the cause of the climate catastrophe??? So…all good!”

Er, no. All that carbon being sucked into the ocean gets turned into acid. So the planet is now experiencing Ocean Acidification. That’s bad – very bad. Especially for our friends, the Dungeness megalopa. And for us. How bad? 

Here goes, courtesy the US Government: 

Bleached corals from acidification courtesy IUCN

“Researchers determined that the current rate of ocean acidification is faster than at any time in the past 300 million years…This shift, which is already being observed around the world, lowers the concentration and availability of ocean chemicals that many marine organisms need to build their skeletons and shells.”

Hey, what was going on, 300 million years ago?  You may want to sit down, before reading the answer.

It was called “The Great Dying”, the Earth’s most severe known extinction event, with the extinction of 57% of biological families, 83% of genera, 81% of marine species, and 70% of terrestrial vertebrate species.[11] 

And the US Government says we’re heading for The Next Great Dying, unless we kick our fossil fuel habit.

Ocean acidification doesn’t really communicate the horror of what it does: eating into the shells of oysters, rotting the coral reefs, dissolving the crabs’ exoskeletons: really,  more of an oceanic leprosy. 

Imagine for a moment a new Covid variant. You brush against the door jamb of the bathroom door and your skin peels back to the bone. You scrub a bit too hard and the toothbrush takes a divot out of your tongue. Pulling on a tight sock might take off a toe.  That’s what’s happening to life in the ocean.

That’s why we’re helping Hakai. By counting the crab critter babies and adolescents, we’re standing guard. We’re sentries, on the frontier of the climate crisis,  guarding the Sentinels, by helping scientists like Matt Whalen build their knowledge base, and doing our job to let our fellow citizens know that it is not too late to care. 

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