That is not the opening line of a joke. This is very serious. Answer: Detritus.

You might think of the flying squid as a strange and unusual form of squid, but actually, the term refers to an entire family of squids, the Ommastrephidae, which, in turn, includes the squids we eat. There are over 20 species of the Ommastrephidae, including the jumbo flying squid, the luminous flying squid, the neon flying squid, and of course, the lesser flying squid.

If you go to a resturant and get calamari, you will be eating a flying squid.

Squid is one of those animals we are not too picky about, when it comes to nomenclature. Even though there are may species of squid that are trapped and cooked up by humans, nobody seems to differentiate among the different species, or at least, not very often. This is a bit like being served a steak, and when you ask what it is, the answer is, “Mammal.” Or perhaps, “It is a member of the Ungulata. Would you like a side of fries with that?”

(Shrimp is similar, but maybe more so. The things we call shrimp, without too much differentiation other than size, come from multiple suborders).

Here’s the thing, and the reason that the new research I’m telling you about here is interesting. Squid forms some or a large part of the diet of many human groups around the world. But beyond that, squid (Ommastrephidae) forms the basis for the diet of many many species of other things that we eat. They are at the top of their own little food chain, as carnivores, up until they get eaten by a human, fish, or something. Ultimately, a huge part of human diet and economy, and more importantly, of the ecology of the entire oceanic fauna, relies critically on squid.

Yet, until recently, we did not know what the larval squid ate!

From the abstract:

While the diets of adult flying squids have been extensively studied, the first feeding diet of early paralarvae remains a mystery. The morphology of this ontogenetic stage notably differs from other cephalopod paralarvae, suggesting a different feeding strategy. Here, a combination of Laser Capture Microdissection (LCM) and DNA metabarcoding of wild-collected paralarvae gut contents … was applied, covering almost every life domain. The gut contents were mainly composed by fungus, plants, algae and animals of marine and terrestrial origin, as well as eukaryotic and prokaryotic microorganisms commonly found in fecal pellets and particulate organic matter. This assemblage of gut contents is consistent with a diet based on detritus. The ontogenetic shift of diet from detritivore suspension feeding to active predation represents a unique life strategy among cephalopods and allows ommastrephid squids to take advantage of an almost ubiquitous and accessible food resource during their early stages.

Here’s a picture:

Fernández-Álvarez, Fernando, Annie Machordom, Ricardo García-Jiménez, César A. Salinas-Zavala & Roger Villanueva. 2018. Predatory flying squids are detritivores during their early planktonic life. Scientific Reports volume 8, Article number: 3440 (2018) doi:10.1038/s41598-018-21501-y

A No-Wake Rule means the oversized fishing boats and smallish cabin cruisers that normally ply this large exurban lake need to all go at 5 m.p.h. or less, and forget about wake boarding, water skiing, and all those other fast, wake churning activities. The result? A lot of butt hurt, a near First World depression setting in in the Twin Cities wester suburbs. Somebody took away our boy toys!

But then, somebody went fishing. It isn’t a great fishing lake. It is mainly a go-fast lake. In fact, it is on this particular lake, I believe (with no evidence I quickly add) the method of fast-trolling for muskies was invented. This is a way to “go fishing” and go fast at the same time. You drag the lure behind you as fast as your boat will go. It is said you can catch muskies this way. To my knowledge it has never happened. Just more boy toy.

Anyway, somebody went fishing on the No Wake Lake, and guess what happened? They caught a boat load of fish! Literally! Then their friends went out fishing, and they caught a boat load of fish too! Pretty soon all the fisherpersons who had access discovered that when you don’t drive giant boats back and froth across the lake at high speed all day, the fish feed. When you do, they hunker down, feed infrequently, and grow slowly.

Now, I’m not going to vouch for this relationship just yet, but it makes intuitive sense. In my own experience, quiet places are where you catch fish. If I’m fishing up at the lake, once the boats start driving around skiing (say on a fourth of july weekend) I might as well reel it in and go get a beer, because that’s the end of the fishing. I’m pretty sure my best fishing has been on Wednesday and Thursday, before the startup of the loud and noisy weekend. And that’s on a quietish part of a relatively quiet lake.

The only reason I’m mentioning this now is because I came across this story from my Science News Roundup:

The blare of human noise causes birds to pipe down and frogs to breed less frequently. Now, scientists have found a humanmade sound that has a far more colorful effect: The boom of a ship’s engine makes common cuttlefish (Sepia officinalis) change the complex swirls of skin hues, stripes, and spots that they use for camouflage and communication. …when researchers placed a loudspeaker near cuttlefish tanks and played the sound of an underwater engine, the animals swam more and changed colors more often. They also raised their first pair of arms, which are used to sense water movements, more frequently…The sounds of crashing surf had no effect, providing the first evidence that engine noise may stress the animals out.

The original story is here, in American Naturalist.

I would love to see a large number of large lakes shut down for boating. No motors. Eventually, of course, there will be no gas powered motors, with the shut down of fossil fuels. I promise you, when we start using quiet electric boats for fishing, the fishing will get better.