Tech

Marine ecology has dark fish

It started with a tweet:

Imagine if ornithology was like physics where we had some sort of "dark birds" that represent 95% of all birds but we just had no way to detect them besides the effect they have on other birds.

And a follow up from Dr Andrew Thaler, deep-sea ecologist and population geneticist:

There's a globe-spanning layer of mesopelagic fish that is so dense it distorts SONAR. For decades we had no idea what created the Deep Scattering Layer or why it moved. We still know almost nothing about it.  It contains 65% of all fish biomass.  Marine Ecology has Dark Fish.

Now, I’ve written about a different kind of dark fish known as “vantafish” but these dark fish are extra special. According to Dr Thaler and this post from Phys.org, 65%–95% of all fish biomass may hide in a mesopelagic zone, an area between 100–1000m below the surface.

Professor Carlos Duarte, a marine biologist and Distinguished Professor at the King Abdullah University of Science and Technology, led a seven-month team circumnavigation of the globe collecting echo-soundings of mesopelagic fish where he found that they were able to detect nets from at least five metres making catches for biomass calculations difficult, hence the wide estimates.

(h/t @PublicStilli)

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