The ocean provides food for billions of people. But even those who don’t touch seafood and never set foot on a beach are connected to the ocean. The ocean is so integral to our climate that declining ocean health will fuck with every single person on this planet in some way.
Most of the ocean is already affected by multiple human-made stressors. The big fuck-ups humanity is throwing at the ocean are overfishing, habitat destruction, warming sea temperatures, ocean acidification, oxygen and nutrient depletion, sea level rise, intensifying storms, shifting ranges and species abundance patterns, but also timeline mismatches between prey and predators.
We’re putting the ocean through a lot. And most of us don’t give a fuck at all.
The industries connected to the ocean add 150-450 billion USD annually to people’s pockets. I’m not saying it’s going to the right pockets but it sure does matter.
Both science and anecdotal evidence have shown the effectiveness of MPA as a conservation tool but also, probably at least as importantly, as a buffer for more traditional fisheries management and climate change.
The climate doesn’t care where emissions come from. Humans all over the world feel the effects–especially those who don’t have private jets and air-conditioned top-floor offices. Even if all the countries acted now to lower emissions as per the 1.5-degree target of the Paris Agreement that they all agreed to, we will continue to feel the impacts for at least 50 fucking years.
So, right now, and I mean right now, right now, we need to work on two things: immediate reductions in emissions but also mitigating measures to buffer against what will definitely come. Unfortunately, underinvesting in environmental protection is still the norm.
Let’s have a look at the different stress-factors the ocean has to deal with:
Overexploitation of marine stocks
I’ve talked about this one time and again but it bears repeating:
A vast portion of fish stocks globally is overexploited. Some regions are doing especially bad: at least 40% of North-East Atlantic stocks and 87% of Mediterranean and Black Sea stocks are fished unsustainably.
As I said before in a video on fisheries management, the EU’s Common Fisheries Policy (CFP) that came into effect in January of 2014 should’ve put an end to this. In 2018, 69% of European stocks were still being overfished. More than half were even outside of safe biological limits. Oh, and only 12% were in accordance with that great goals they all signed when they signed the CFP. The deadlines set out by the CFP to end overfishing and stop harmful subsidies were 2020, as so many other unmet targets.
So, let’s just move the goal post to 2030, another nice-sounding round number? Or should we go for 2050, because it’s an even nicer-looking number?
In 2018, an estimated 4.6 million fishing vessels were registered to fish the ocean. And that’s just the registered ones. In addition, there’s illegal, unreported, and unregulated (IUU) fishing. A study by Welch et al. from 2022 found that we lose about 10-25 billion USD per year to IUU fishing. Every fifth wild-caught fish is likely harvested illegally.
You’d think the tracking system of fishing vessels would help but AIS (Automatic Identification System) is not required for all vessels and sometimes you actually have good reasons to turn that thing off like avoiding pirates or keeping that perfect fishing ground from the big guys looking to harvest it all.
This, of course, makes it hard to figure out how much is being fished, how much is left, and how much can be assigned as quotas for the coming season, making fisheries management even less effective than it already is. And keep in mind that politics often trump the scientific advice. And then, assuming all that goes right, the fishers have to follow, not trick with things like fishmeal and throwing catch overboard illegally (which takes it out of the calculation while many fish still die).
And then there are the indirect impacts like using up fuel (the fisheries sector is responsible for 1% of global emissions, not including all the carbon stored in the fish they take out) and fucking with the seabed.
Especially high-sea fishing is fucking unsustainable and uneconomic but we keep throwing money at the problem instead of the solution. Large sums still subsidize fisheries while funds are low for marine conservation.
Warming oceans, oxygen depletion, and shifting ranges
Organisms, no matter if on land, in the ocean, or in the air, fit into a thermal niche, so they have a temperature where they do best and in both directions from there, performance declines. Just think about trying to focus on work in an office at 30 degrees or while shivering through a snow storm.
From genes to ecosystems and across the globe, warming oceans affect marine life. Some organism adapt better, others are fucked.
Most of the world is currently sweating through a heat wave–while I am putting on a sweater in the morning because the Baltic region near Rügen is somehow skipped by all the heat. Well, heat waves also exist over the ocean. As I said, the climate is all connected.
Marine heat waves have become more frequent and extreme over the last century with more than a 50% increase between 1925 and 2016. So, we’ve got climate-change-driven chronic warming and then we’re adding short-term heat waves with more warming.
To deal, organisms are changing their behavior: some migrate vertically into deeper waters with less sunlight, while others migrate toward the poles. These large-scale shifts have been well-documented. If it’s warmer, organisms need more energy which means eating more. If you are hunting, you can’t hide in a refuge from the heat (and might get eaten). And then temperatures fuck with reproductive cycles. It’s really bad all around.
Many species shift their ranges (which then fucks with fisheries management because that giant swarm of sardines might now be in another country). But other species can’t just flee. There are quite a few loyal-as-fuck species out there that return to their traditional breeding grounds. Especially sea birds and sea mammals, but also fish like eel, often return where they were born. These species–among them many humans actually give a crap about–are especially vulnerable to climate change.
And some organisms can’t deal at all. Coral reefs belong to both the most biodiverse and threatened ecosystems. Coral, which are sessile organisms once adults, don’t exactly have the option to just walk away. They aren’t anemones, after all. We’ve all heard about coral bleaching before. If you haven’t, I highly recommend Netflix’s “Chasing Coral” which documented that effect very, very well (and is now available on Youtube.)
Often overlooked, seawater warming also leads to mismatches between predator and prey. A spring plankton bloom might happen too early for the fish babies relying on it.
The warmer water is also less able to keep gases in solution, so we get lovely oxygen-minimum zones which are also called ocean deserts because little life survives in them.
My favorite ecosystem, kelp forests, are suffering too. Kelp forest dieback is one of the most common pervasive warming responses. Kelp is responsible for vast amounts of carbon sequestration, so getting carbon dioxide out of the atmosphere into the ocean.
A lovely downward spiral of fucked-up mess.
Speaking of carbon dioxide… the ocean is alsogetting more acidic. The ocean is our largest reservoir of organic carbon and likely the only net sink of anthropogenic carbon dioxide emissions. With tree-planting spread widely as the tool against climate change, I think we should probably talk more about the ocean, especially as scientists are questioning the validity of mass-tree-planting solutions globally.
The ocean gobbling up the carbon we throw into the atmosphere has slowed warming. But this buffering comes at a cost: the ocean is already 26% more acidic on average than it was in preindustrial times. Roberts et al. (2017) expect that to increase by 100% or more by 2100 if we don’t get our collective shit together.
The ocean is pretty resilient. She can balance her pH pretty well with mangrove forests, fish that migrate down into the depth, and some other buffering mechanisms. But there are limits.
Fish and other ocean organisms are already losing habitat to warming oceans, as we just saw, but there are two more major drivers of habitat destruction: land-use change to make room for humans instead of nature and destructive extraction methods.
We are hardening shores left, right, and center, until little natural shoreline is left. In the US, for example, 14% of shorelines are already hardened, and we are losing essential tidal wetlands, especially in the South Atlantic and Gulf of Mexico. It’s a global trend, though. We’ve lost more than half of our wetlands–another place where shittons of carbon dioxide are stored with biodiverse ecosystems…
Inland dams, deforestation, and agriculture change the composition of river run-off, depleting necessary nutrients while increasing salinity and blocking sunlight in shallow waters. Container ships and tankers can lead to further issues for coastal and open-ocean systems by damaging ecosystems with hulls and anchors or releasing oil.
A great time to live in the ocean…. but I’m not done.
In addition to habitat loss due to humans needing more room for whatever, destructive fishing methods like bomb fishing, bottom trawling, dredges, an poisoning are wreaking havoc to marine ecosystems. In the deep sea, first explorations for deep-sea mining are performed and while, to date, deep-sea mining isn’t profitable yet, desperation might lead companies to explore this option more in the future.
One of those studies that I can’t forget about was written by Sala et al. in 2021. They explored the effects of bottom-trawling and dredging and found that only 1.3% of the ocean was trawled between 2016 and 2019. But even that low percentage likely released 1.47 Pg of carbon dioxide.
Even more destructive methods like fishing with explosives are illegal in large parts of the world but still done frequently. As you can probably imagine, throwing bombs into the water isn’t exactly a selective fishing method. The practice can destroy entire ecosystems. Poisoning is just as non-selective and destructive.
But even the less destructive fishing methods are often pretty detrimental to marine life–and not just the ones that are caught. Longline fishing dominates much of high-sea fishing has high bycatch rates for marine mammals, seabirds, sharks, and sea turtles. The same species also often get stuck in plastic debris in the ocean which The Ocean Cleanup Project has shown to largely consist of fishing-related trash.
Marine protected areas can’t stop heat or acidity from getting in, but they have shown to make ecosystems so much more resilient. When hit, the protected ecosystems recover more quickly and damage is often less in the first place.
We need the ocean. We need the ocean so fucking much. It’s high time we stop looking the other way and demand change. Let’s protect the ocean to save all of us.