The Fish Story

Marking Fish Using eDNA; Bat-Flavored Spring Mix

By JAY MANN | Apr 19, 2017

DNA DON’T LIE: T’was a Beach Haven old-timer, Chris Sprague, who would jerk the chains of us kids by sniffing a pinch of bay water and authoritatively telling us what fish were around. Oh, we kinda knew he was joshin’ us one good. Still, what if, just maybe, he really could tell what fish were a-swim with just a sniff or two? So we’d rig for whatever he said he smelled.

Though Chris has since passed – at, what, 90-plus? – and took his sniffing secrets with him, something highly akin to his water-pinching magic is now reemerging. It’s in the form of a science breakthrough of monumental fishing importance.

To understand this breakthrough, you must first loosely grasp a research development that is turning the world of nature knowledge on its esoteric ear. It’s based on something called eDNA, which stands for environmental DNA.

In its simplest measure, eDNA focuses on extracting assorted and sundry DNA samples/signatures from within environmental sources, be it water, soil, rain or even wildlife droppings. It’s a form of shot-in-the-dark researching, taking what the samples are giving, DNA-wise. From the samplings, a broad picture of both present and on-the-move fisheries can be gleaned. It is highly likely that eDNA holds the future of fishing in its palm.

For the past six months, researchers at NYC’s Rockefeller University have been taking surface-water samples from the Hudson River and the East River once a week, from specified points. They then magically – let’s just say there’s no easily explaining how they do it – sort out DNA markers from within the water sample. From those, they accurately know what fish are in the ’hood.

Through such pioneering work, it is becoming possible to follow fish presences and migrations without going through the tedious netting rigmarole. Currently, fish counts are taken using random trawling methods. This technique has long had its accuracy questioned. Netting also leaves released fish feeling gray behind the gills.

“Indeed, eDNA science is quickly granting humanity a very old wish: an easy way to estimate the abundance and distribution of diverse fish species and other forms of marine life in the dark waters of rivers, lakes, and seas,” reads an article in phys.org, titled “Naked DNA in Water Tells If Fish Have Arrived.”

“Environmental DNA strained from quart samples … revealed the presence or absence of several key fish species passing through the water on each test day,” explains the article.

What they’re deciphering, daily, through eDNA “hits” amounts to a dynamic look at fish goings-on down below. In the Rockefeller U. study, the main DNA contributors have been menhaden (most common), conger eel (rarest), herring/alewife, striped bass, American eel, mummichog, black sea bass, bluefish, Atlantic silverside, oyster toadfish, tautog and bay anchovy.

Applications of this genetic fishing technique are about to be used to monitor globally invasive fish species.

The U.S. Fish and Wildlife Service reports, “eDNA is used to monitor for the genetic presence of bighead carp and silver carp, two species of Asian carp. By sampling waters that could potentially be invaded by these species, the detection of their DNA can indicate the potential presence of the fish itself.”

The reading of eDNA would surely do wonders in Barnegat Bay. It could easily indicate the presence and comparative biomasses of our spring/summer migratory and spawning species. What’s more, eDNA-ing will likely offer a read on less fishy bay occupants, like mollusks, especially clams, bay scallops and, most critically, oysters. At the same time, it will offer leads on unwanted crustaceans, including green crabs and Chinese mitten crabs.

This whole eDNA thing is a metamorphosis of Uncle Chris’ sniff-testing a pinch of bay water. In fact, I can all but hear his gruff voice from above, “Hell, I did that  my whole life … and they’re probably charging an arm and a leg to do it!”

FINAL BIT OF BATTINESS: A while back I wrote about my kid-time freak-out when a captured bat crawled up my neck as I biked along. That write-up surely inspired a slew of folks to email me a world-viral story about a pretty disgusting bat misadventure that befell a salad-loving couple in Florida.

As I read it, the two were merrily munching on a Fresh Express bagged salad kit, a favorite brand of mine, when one of them came across a decomposing bat amid the company’s spring mix. It was not listed in the ingredients.

I have a steel stomach and highly manly temperament, but I could see even me forking up a rotting bat and loosing a girlie “Oh, gross!” – two-syllabizing it into a lengthy “gaaar-oosss!” … maybe even adding, “I’m never eating again.”

Doing what might be called decompositional damage control, Fresh Express folks darted around the country, not unlike bats at night, grabbing all its bags of spring mix off the shelves – while warning one another, “Don’t look inside! You don’t want to know.”

In newsily explaining the bizarre bat-in-bag incident, the company suggested a wayward bat had lit upon in-field lettuces and greens, the essence of spring mix. It had then been swept up by a chopping machine that harvests the tender leaves. After harvesting, the likely-dead bat had apparently been overlooked by factory inspectors, thinking it was a hairy, brownish radicchio leaf. In the bag, it decomposed. At this point, I envision sitting at a dinner, driving a fork into the salad and pulling out a … “Uh, might I be excused for a moment, please? And your bathroom is where?”

By the by, it wouldn’t seem you can get rabies from eating a dead rabid bat – or a closely-related salad, in this case. That said, there are scant few precedent-setting rabid-bat-eating cases. However, I’d be sorely remiss by not bringing up heavy-rock ultra-legend Ozzie Osbourne, who delightfully disgusted millions – and himself – by biting off the head of a bat during a concert. Come on, even you of a classic-music ilk want to hear the sordid details.

In a Times interview, Ozzie admitted that he fully believed it was a rubber bat that some Black Sabbather had thrown up on stage. It was a thematically appropriate prop to throw at a frontman once dubbed “the mumbling vampire.”

“Immediately, though, something felt wrong. Very wrong,” Ozzie recalled. "For a start, my mouth was instantly full of this warm, gloopy liquid, with the worst aftertaste you could ever imagine. I could feel it staining my teeth and running down my chin … Then the head in my mouth twitched." Gaaar-oosss!

Despite Ozzie’s apparent survival, both the Fresh Express dead-bat diners are going through something called a rabies post-exposure prophylaxis regimen, chock full of needles. It’s a good thing the couple have each other since dating after being recognized as a confirmed dead-bat eater limits one to only the weirdest courting opportunities.

While Fresh Express sales have temporarily dropped faster than a diving bat, I remain a dedicated customer. Hell, I’ve never been all that wild about spring mix anyway. I relish their green greens. Of course, the first decomposing green mamba I find in my Fresh Express Caesar salad …

RUNDOWN: Big-ass blues are back in town. Slammer takes last weekend ran from a mere one/two to over a dozen.

I got word of blues being taken mainly by bunker-chunk casters, though jig/plastic tossers were also feeling the bluefish wrath – feeling it more than hooking into it. Even larger blues are habitual tail-gunners, ripping off the tails, then being put off by the tastelessness of it. It remains astounding how even attack-anything blues lose all interest in plastics once the tail is bitten off.

A few bass were pulled from the surf, a nicer going for a plug, just north of mid-Island. Overall, though, beach bassing was low in intensity, as might be expected when hordes of blues are recklessly blasting about.

Bayside bassing is still quite hot in spots, though keepers are keeping their distance. Ask for hot-spot exactness at local tackle shops. Sure, you can also ask in Walmart’s sporting goods. Tell me how that works out.

“Do you know if there are any bluefish around?”

“Our pet department is up front and to your right, sir.”

Blackfishing has been red hot … seas allowing. Spring is always a wind machine, making it tough to get hulls to hang over or near the structures where the tog roam.

White perching is hitting its pre-spawn stride. I don’t go overly informational on their exact whereabouts. Perch holes are often in confined areas and can get crowdedly testy. Local tackle shops will sometimes offer directions.

Should you home in on a hole, the best bite time is late-day. Best bait is shrimp. Best gear is light to ultralight. Bobbers and split shot shine.

I will hint that there are perch hot spots along the Road-to-Nowhere, Manahawkin. I once fished a creek-ish spot there that was no wider than a couple side-by-side Chevy trucks. For over a week, I had big perch on every cast, using tiny pickerel spinners. Then, I rushed back one a.m. with a slew of new spinners to try, and the pond had turned pale white on the surface. Yep, the perch had spawned out … overnight! Not a touch.

I have a couple more reports of smaller (male) black drum, in the 10-pound range. That migration is well within our range. Big fish likely any day now. Clams, up to three deep, stacked on larger circle hooks work well for cows. LBI has seen them up to 100 pounds.

BLUEFISH BELOW: Let it begin. Once again, the vernal bluefish arrival is heralded by choppers, as opposed to the smaller, more traditional cocktail blues. Seeing slammers being taken ocean, inlet and bay, it is becoming more likely that big blues will rule the spring roost again this year. Last year was one for the record books, with an avalanche of mega-blues, most popularly being taken off the Barnegat Inlet South Jetty.

During last year’s slammer insanity, I was more inclined to get photographs of the action. I'm not going to slight myself this go-round. I hope to put up a big supply of dried/smoked/jerky bluefish this year, using two driers with a total of 12 layers. I’m also going with a newer, hotter flavoring ... more Cajun.

By the by, I have a dang decent palate for fish, and I’ll assure that spring blues are the sweetest, based on their fattening up on crustaceans more than bunker. In fact, bayside blues are tops due to the massive amount of grass shrimp they can down. Many a stomach-content look proves how shrimpy and crabby spring blues can be.

If filleting blues for drying, smoking or making jerky, pay special attention to removing darker lateral line meat, along with any batches of darker meat just under the skin. That darker meat can really fish-ify dried products, meaning it can offer a tad too fishy of a flavor.

Also, even the best handled dried/smoked/jerky bluefish is best kept refrigerated after it’s made. Admittedly the jerky can last at room temp, though why risk it when it’s just as tasty at fridge temps?

jaymann@thesandpaper.net

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