Is a change coming?

[Mole-Patrol]

Hovis, there are two small ponds on the outskirts of Barnsley that are old mine shafts. Neither pond is connected in any way to the canal or river system. The lowest pond is about 50 yards from and 10 yards higher than the old Fitzwilliam Canal and further and higher from the River Dearne. Yet when I used to fish them in the 1970's eels up to around 2lb were regularly caught.

There may be another explanation given the eel's lifespan, but I can't think of how they would come to have been stocked there except accidentally.

[Santiago]

I've read and heard about eels moving over land, to an extent that back in the day farmer's would find eels in there cow troughs. Is this make belief then. Even heard it on respected TV fishing programmes.
A man made obstacle is quite a different barrier compared to no obstacles at all, like a shallow bank.

[Hovis]

Hovis, there are two small ponds on the outskirts of Barnsley that are old mine shafts. Neither pond is connected in any way to the canal or river system. The lowest pond is about 50 yards from and 10 yards higher than the old Fitzwilliam Canal and further and higher from the River Dearne. Yet when I used to fish them in the 1970's eels up to around 2lb were regularly caught.

There may be another explanation given the eel's lifespan, but I can't think of how they would come to have been stocked there except accidentally.

Indeed Clive. The species is quite a mystery isn't it. It makes little sense that anybody would have stocked eel formally (or informally for that matter), they are neither a highly prized angling species or worth all that much (although prices now for smoked eel is eye watering). The only logical explanation is that they've simply found there on way in there which, and I agree, is perfectly reasonable. I've fished farm ponds in the past miles from any for of true river or stream and they've contained eels, no doubt as a result of the extensive network of drainage ditches offering some form of connectivity.

[Hovis]

I've read and heard about eels moving over land, to an extent that back in the day farmer's would find eels in there cow troughs. Is this make belief then. Even heard it on respected TV fishing programmes.
A man made obstacle is quite a different barrier compared to no obstacles at all, like a shallow bank.

Are there any respectable well researched TV fishing programme? anyway re: turning up in troughs. I've read similar accounts in the past but these date from the 40s. Again possible - all about context isn't? A low lying field on a floodplain seems reasonable perhaps even dropped by a passing heron? If its in uplands miles from the nearest river I'm more skeptical. Like you Santiago I'm a man that needs to use science as an evidence base. Although don't mistake this for me thinking that if it hasn't been studied it hasn't taken place.

Also, barriers. I'm well aware of the hugh variety of differences in type and form. It's a subject in its on right!

If you are really interested about eels I'd recommend the below. A word of caution and that this really is set at full eel geek level.

"Eels - Biology, Monitoring, Management, Culture and Exploitation: Proceedings of the First International Eel Science Symposium"

https://www.nhbs.com/eels-biology-monit ... ation-book

[Kev D]

I kept a pet eel in a baby's bath in the back garden when l was a lad . It was only there for a few days before it unsurprisingly disappeared. A few months later ,it ,or one like it turned up in the neighbour's garden pond when they cleaned it out.
I reckon that an animal with instincts capable of guiding itself across oceans and up and down stream according to its stage of development is probably quite capable of "sniffing" out potential habitats. Eels seem pretty good at sensing the way back to the river from the unhooking mat so l think it quite believable that if they sensed a more appealing water nearby they might move to it even if it necessitated an overland trip .

[Hovis]

On the face of it, this sounds like a good news story, and that's what I thought when I first read the original post. But now I'm not too sure, because I have a few questions.

Firstly, what's the current level of the parasite in European eels, the one that causes their swim bladder to disfunction, and sink into the abyss once they swim over the continental shelf, never to reach the Sargasso Sea and reproduce?

Secondly, how does the EA know that the returning elvers originated from eels that matured in Europe ?

Perhaps we're reaping the benefits of conservatory measures carried out in the States.

These questions need answers otherwise how do we know that the elvers do not originate from eels that matured in America. Isn't it thought that both 'American' and 'European' eels are but one species that both mate in the Sargasso Sea, so that the elvers carried by the sea currents to European waters might have parents that spent their lives in American rivers? At least that was thought a possibility a few years ago! I expect the science has changed and I'm not familiar with current views on this, I expect they now use DNA to determine the parental lineages of the incoming elvers, and perhaps they tag our mature eels all the way to the Sargasso sea!?

I can't see much point to the EA's work if the parasitised numbers are high and all of our mature eels aren't getting to the Sargasso Sea! Though I expect its early days so they will not know for several years!

What I've read about this mysterious fish is probably out of date, hence the questions!

Notwithstanding, it's great that the EA are helping the new arrivals!

Santiago,

So many questions. so lets start at the top.

"Firstly, what's the current level of the parasite in European eels, the one that causes their swim bladder to disfunction, and sink into the abyss once they swim over the continental shelf, never to reach the Sargasso Sea and reproduce?"

Here I'm assuming you are referring to Anguillicoloides crassus the parasitic nematode worm?. Indeed, as you say, it is impacting the european eel, Anguilla anguilla, but to what extent we do not know. To date it has been impossible to track silver eel movements to their spawning grounds let alone study the impact of a relatively newly discover (in Europe) parasite. If you've got any papers on this I'd be interested to see them.
There is also Anguillid Herpesvirus (AngHV1) to contend with. First discovered by the EA following an eel mortality in 2009 (from memory) Eels infected with AngHV1 can develop a range of disease signs and symptoms. Diseased eels may appear lethargic and swim near the surface or the water's edge. They may have reddened fins and a mottled appearance to the skin. The main damage caused by this virus is to the gills, with necrosis (cell death) and loss of normal gill structure. The internal organs can also be affected with inflammation and further necrosis. These changes cause organ failure, leading to debilitation and death. What the impact in on the entire population is impossible to say but its another factor to consider in the plight of eels.

Secondly, how does the EA know that the returning elvers originated from eels that matured in Europe ?

There are many species contained within the genus:Anguilla The European Eel Anguilla anguilla is different to the American Eel Anguilla rostrata and as far as I'm aware they do not communally spawn it or successfully mate. I've found no referance to A.rostrata being reorded in Europe. When spawned the eggs metamorphose to The larvae, leptocephali, which drift towards Europe in an approx. 1 year migration largely influenced by oceanic currents. Indeed the increased numbers in recent years could be a result of a minor change to the gulf stream. Some new research has shown that eel can use the earth's magnetic field to orientate themselves in the direction of the possible estuary where their parents left. Staggering stuff really. To me this means the A.anguilla is really a true european species.


I can't see much point to the EA's work if the parasitised numbers are high and all of our mature eels aren't getting to the Sargasso Sea! Though I expect its early days so they will not know for several years!

Just because we don't know doesn't mean we should stop. What happens if the parasite isn't having an impact or only a minor one? We might well miss the chance to reverse the decline.

It should also be noted that although the EA has certain obligation to all freshwater species it isn't alone. The Eel Regs 2009 impact many from farmers to water companies and give a definitive legal basis for changes to be made, such as increased passage opportunities and screening for abstraction. We are all in this together.

The aboves a bit scrappy as I've done it on a phone but I trust it answers your questions?

[Santiago]

Excellent answers Hovis. Thanks for taking the time to answer my questions, and you have reassured me no end that the EA is doing a great job with respect to bolstering eel populations. I only ever fish for them about once or twice a year, and catch a range of sizes!

[Kev D]

20200501_144439.jpg

Their own figures indicate up to 500 kilos of evers being caught just from the Severn in one day during the elvering Season of 2013 . Had even a fraction of that lot made it to adulthood some of them would be ready for the return journey to the breeding grounds about now. At 2500 to 3000 plus elvers to the kilo that's a lot of eels the EA are going to have to replace one way or the other.

[Liphook]

That's the bit I just don't get KevD - hundreds of fisherfolk? Really? Are the licensed by the EA or local IFCAs? If so why?

[Troydog]

I attended (skype) a meeting of the Wye Local Fisheries Group yesterday where it was confirmed that huge numbers of elvers are ascending both the Wye and the Severn, although no one could explain the abundance. The EA representative acknowledged the situation but added that no restrictions are in force. It sounds like a free for all at the moment....