Aquarium Fish Blog

Is Global Warming Shrinking Your Fish?

Is Global Warming Shrinking Your Fish?

Aquarium Fish Blog

That’s what some scientists think. In a paper published online for the journal Nature, scientists used a statistical model and computer simulation to conclude that global warming could actually cause fish to shrink in size over the next 30 years.

The paper states that as the temperature of the ocean rises, the amount of dissolved oxygen in the water decreases. That reduced availability of oxygen is then thought to have a profound effect on the size and growth rate of fish. The model looked at 600 species of fish, in oceans around the world, and projected that fishes from the Indian Ocean stand to shrink the most.

In the study, the scientists state that this is the first-ever attempt to use scientific models to examine these effects on a marine ecosystem.

I never thought of this before now, but perhaps the rampant popularity of nano tanks in the saltwater aquarium hobby is a side-effect of global warming. Who knows, maybe by 2050, as the scientists speculate, we’ll have Nano Nemos.

I encourage you to check out the original publication for yourself, titled:

 Shrinking of fishes exacerbates impacts of global ocean changes on marine ecosystems by Cheung et al.

I personally found it to be a bit preachy (on the topic of global warming) for a publication purporting to be scientific—but their theoretical model is certainly intriguing. I did some additional digging, and found a publication that demonstrated (with scientific evidence, rather than a computer model) that oxygen concentration did have a direct positive effect on the growth of halibut in aquaculture—so by subtraction, the Nature scientits’ model seems to make some sense and passed my own personal ‘sniff-test’.

That paper on the effect of dissolved oxygen in aquaculture is titled:


What I’m thankful for, here, is that this release gave me a moment to pause and reflect about being a little more green in what I do every day, as well as a reminder of how delicate the balance of nature can be—and to take a moment to appreciate the fish and invertebrates we keep in our aquariums.

But I also wonder if, as hobbyists, we should take a very direct message here to be mindful of the temperature and oxygen levels of our fish and reef tanks.

I’m going to measure my dissolved oxygen and make sure I’m set up to produce optimal growth.  I wonder how much impact oxygen level could have on the growth of aquaculture fish like the ever-popular clownfish species—and whether or not Nano Nemos are on the horizon. I guess only time will tell. Then again, if we slip into an ice age, I may have to write an opposing piece about Giant Nemos.

What do you think? Will ocean temperature affect the size of the fish we see in the aquarium trade?

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