HomeOpinionPlaying Poseidon in the Gulf of St. Lawrence

Playing Poseidon in the Gulf of St. Lawrence

Humans tend to try to play God with things we barely understand.

At times, some more specifically like to play Poseidon.

We, as a species, are solutions oriented. If we see a problem or a challenge, oftentimes we can put our heads together and come up with a solution. Collectively, we have effectively eliminated diseases like polio and smallpox. We’re also on track to close the Antarctic ozone hole by the mid-century. In less than a century, humans went from the first powered flight to walking on the moon.

In short, we’re collectively capable of incredible things. One thing humans have trouble with, however, is keeping our ecosystems in check. One need look no further than the Gulf of St. Lawrence for proof of this.

In the Southern Gulf, cod have been put on the back foot since the 1990s, mostly from overfishing. The spawning stock biomass of cod has dwindled from a 1950s high of 320,000 tonnes to a measly 12,000 tonnes by 2023. According to Daniel Ricard, a biologist with the Department of Fisheries and Oceans (DFO), cod in the region are now facing “commercial extinction,” which applies when any stock’s biomass falls below 1,000 tonnes.

“Even if it exists at low levels, there will always be some cod in the Gulf of St. Lawrence. They may not be at the level they were historically, but chances are there will be some,” said Ricard. “So, that completely subjective threshold of 1,000 tonnes is what was formulated at the last assessment as something that would represent a level beyond which, basically, the population would not be able to sustain any kind of exploitation.”

While human activity has put cod at a disadvantage, severely reduced fishing activity in recent years means we’re no longer their number one enemy. This title, according to DFO scientists, goes to grey seals. As fishing mortality has plummeted for cod in the region, indices of natural mortality have skyrocketed.

“These seals live in a fish market, essentially, and they have a number of prey they can consume, and one of these prey is cod. That’s the most plausible cause for these increases in natural mortality,” said Ricard.

At around 420,000-strong, with an ability to eat between three to six kilos of fish every day, grey seals have become a noticeable hurdle to the recovery of the once-abundant cod stocks. In the face of such opposition, the human instinct to take matters into our own hands and “play god” for the benefit of cod calls to us.

The answer seems cut and dry, right? Kill off a large portion of the seals to give cod a fighting chance.

This simplistic answer, however, is exactly how we got here in the first place. By trying to manipulate nature to our whims, we risk throwing the ecosystem into a more drastic tailspin than it’s already in. The risk, according to scientists, is that seals are opportunistic feeders. They’ll eat just about anything, including species that may prey on juvenile cod.

According to Ricard, it’s not the abundant seal population that’s presenting a problem, it’s what we’ve done to one of their most plentiful food sources. Supposedly, there has likely always been this many seals living amongst us.

“If you were able to get in a time machine and come back 300 years ago, chances are there were just as many seals as there are now. I think the seal herd has reestablished itself, because they were also hunted quite heavily for the last century or so,” said Ricard. “The cod population was able to sustain that level of predation by the grey seal, but in the southern Gulf, there was quite evident overfishing…”

Compounding with this, the ecosystem in the Gulf has changed and is still changing. Again, this can be chalked up to human activity.

There was once a time where seals directly competed with walruses for pupping grounds, effectively putting both species’ population in check. Since walruses in the Gulf were hunted to extinction, yet another check and balance in the region’s ecosystem has been eliminated.

There’s also the looming threat of climate change — yet another problem created by humanity. With a warming world comes warming waters. With warming waters comes creatures that call warmer waters home, such as the great white shark. With more sharks setting up camp in the Gulf, they will undoubtedly be preying on these problematic grey seals. The problem is that these sharks will be preying on everything else, as well — including cod.

Our actions have obviously had unintended consequences. By overfishing cod, we’ve thrown off the balance between them and seals. By extirpating walruses from the Gulf, these same seals have run amok. By letting climate change go unchecked, we’ve opened shop for an increased presence of opportunistic apex predators.

Intentionally or not, we created this domino effect. As much as the very nature of humanity may make us want to step in and “solve” the problems facing cod and the Gulf at large, there may be something to be said about taking a step back and not playing God with delicate ecosystems.

 

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