Fresh Water Mussels- What's eating them?

[werry]

Originally Posted by aquarian31

What would a local community officer be able to do?
Is such an officer empowered by any legislation to take appropriate action If a wildlife threatening offence was taking place?

Its well known that anglers will on various fisheries, legitimately use a rake attached to a rope for the purpose of weed raking to make fishing possible and or enhance what is a practice of groundbait enhancement...again a legitimate activity under present Fishery laws?

Is there any suggestion that the angler at this lake was raking the Mussels for any other purpose and if so, was this enquired into or any opinion held ?

And finally, does the Lake owner / fishery lessee impose any rules to prevent such actions by any person. if not, what is the reason for raising this observation !
These questions need asking to stop unfounded allegations being " raked Up"


Finally. does Ukwildlife actually contribute anything financially to any lake owners for the protection of waterways in his location ( please don't use council lakes as an example which are often badly neglected nationally by many councils )

Hear Hear. PLUS A water near to me has had working parties organised by the local angling club to clear rubbish,a supermarket trolley,bike frames,tyres etc,all willing volunteers.

[Ukwildlifeo]

Originally Posted by aquarian31

What would a local community officer be able to do?
Is such an officer empowered by any legislation to take appropriate action If a wildlife threatening offence was taking place?

Its well known that anglers will on various fisheries, legitilately use a rake attached to a rope for the purpose of weed raking to make fishing possible and or enhance what is a practice of groundbait enhancement...again a legitimate activity under present Fishery laws?

Is there any suggestion that the angler at this lake was raking the Mussels for any other purpose and if so, was this enquired into or any opinion held ?

And finally, does the Lake owner / fishery leasee impose any rules to prevent such actions by any person. if not, what is the reason for raising this observation !
These questions need asking to stop unfounded allegations being " raked Up"


Finally. does Ukwildlifeo actually contribute anything financially to any lake owners for the protection of waterways in his location ( please don't use council lakes as an example which are often badly neglected nationally by many councils )

This was a country park lake and the chap was a community officer for the local council who own the lake, and therefore the person to report this to. Since this incident they have fenced of an area from fishermen and dogs to give the wildlife somewhere to go.

The raking out of weed may not be illegal, unless of course the pond or lake is a great crested newt breeding pond, then you may be in iffy water legally.

This chap was removing weed (along with at least one mussel!) and he certainly wasn't helping with the current problem of the decline of Potomegon on the lake which has caused the population of small red eyed damselflies to fall from 1000s to 10s (they need floating weed on which to lay their eggs). Perhaps its not against the rules but even so why is OK to rip out aquatic vegetation an important habitat for wildlife in an important toad and damselfly breeding habitat just so he can get free bait or fish easier? Do fishermen have more rights that the wildlife and the people that enjoy it? If it was a lake dug specifically for fishing fair enough but I'm not sure it right in a wildlife habitat, and I haven't even mentioned the amount of fishing line left around...

I don't personally pay towards any specific lakes or rivers and not to not fishing clubs who's priority is understandably the fish. I am a member of Essex wildlife trust who preserve wetland habitat among others and other pond conservation who work to protect from threats like pollution etc. Last year I helped dig a number of ponds for wildlife and I am also a member of Essex Amphibian and Reptile group and we survey and maintain important amphibian ponds. Not sure why I have to have done the above for my points to be valid though.

[Moonrakers]

I live on the kennet and avon canal and while kayaking found that something is eating the swan mussels by the thousand and leaving small piles of shells on the non-towpath bank under trees.

At first i thought it must be a mammal. But after a few more visits I'd vote for birds, and almost certainly moorhens being the culprit here, mainly due to the location and numbers, and the fact there are moorhen roost or nest sites with inches deep of mixed up shells and droppings. It wouldn't surprise me if coots were doing the same on the attenboro pits.

How much are those fancy cameras that you can leave hidden for a week?

[Spurt]

Just back from walking along the Newmill Channel (leads into river Rother) near Rolvenden, Kent.

The EA have recently dropped the water level to aid lilly cutting so much exposed mud. 1000s of swan mussel shells on mud, banks and also up to 100yds away in fields.

No prints, either mammal or bird around the empty ones on the mud. This little mystery is driving me nuts.

[pondsaregreat]

Hi glsammy
did you notice what state these shells were in and how old they were?
When a mussel dies the shell takes a long time - years - to decompose eventually getting paper thin before breaking up as the calcium is leached out. And of course only these shells will be visible when the water level is exceptionally low. Could be possible that some of the older ones get blown about by the wind or moved by water action?

[Aquaticus]

Originally Posted by Ukwildlifeo

Interesting post. the latest research I read showed that a lake in a natural state (ie with lots of vegetation) which has plenty of shelter, there was no decline in fish stocks despite visits by cormorants, herons and otters.

However in overstocked lakes, especially those with introduced carp eating all the vegetation, the density of fish and lack of shelter can lead to serious impacts done by the above predators. So perhaps the answer is better management of fisheries rather than using otters and cormorants.

Interesting you make the point that restoring our rivers and lakes is the answer, especially when fisheries are a cause in of their decline in some cases. The introduction of carp to lakes can have serious impacts and the introduction of fish generally to ponds where they naturally would not occur can have serious impacts to these rapidly dissappearing habitats. Anglers have also indroduced species like zander, rainbow trout and wels catfish, which has caused decline in native species and the introduction of signal crayfish has often happened as they have escaped from fisheries.
There is also the issue of outflows from fish farms and overstocked fisheries putting nutrients in the water and causing eutrophication, and introducing disease.

There seems to have been a lot of rubbish about otters reintroduction spouted by some. The fact is the numbers introduced were not large and theat it is a reintroduction to help them return to areas where various factors lead to their local extinction and not an introduction of an animal that shouldn't be there. Most otter problems can be solved with decent fencing, which fisheries can get funding for. To be honest the calls for culls of otters made by some of the members of the Angling Trust a year or so ago were pretty silly and did nothing to further the cause of anglers.

So I politely suggest the Angling Trust look at some of the impacts made by it members fisheries before calling for the cull of species that are native to the UK.





There is no debating there are many anglers work hard to restore habitat and monitor water quality.



Interesting post. Why in this case anglers may not be responsible, I have seen with my own eyes an angler (well at least someone who was fishing) with a rake head on a rope dragging mussels out of the water on a couple of occasions.

It strickes me that your posts says more about you and your attitude to Angling. One that reads to me as an anti bias against it.

So I'd like to look at some of the points you've made above.
You stated, "the latest research I read showed that a lake in a natural state (ie with lots of vegetation) which has plenty of shelter, there was no decline in fish stocks despite visits by cormorants, herons and otters."
I note this is not cited by you, so we, must, because you've read it, accept it unquestionably? References please?

Well not really, because in such a nondescript state, it fails to answer many questions. Not least, at what time of year was/were the studies carried out? An important question you’d agree, as someone who’s interests are listed as wetlands, amphibians and reptiles.
You would know that I’d have thought, as much of the aquatic vegetation both marginal and submerged dies back or off during the winter months. And in which part of the year are cormorants in greatest numbers? Yep the winter! The birds start to return from September onward reaching a crescendo of numbers from December onwards until early March. This just happens to coincide with the greatest loss of fish hiding habitat, leaving the stocks readily open to predation by them. It also coincides with the greatest clarity of water, in stillwaters.

Mark Lloyd has explained cormorants are not a native inland bird in the main, but due to over fishing the seas and coastal waters have been forced to seek food inland.
40 years ago it was rare to record seeing them on inland waters. Not today though!
The enforced inland migration for food has decimated many inland waters of their native stocks of fish.
Elton Reservoir Bury is a case in point - when it was drained and electrofished to remove the remaining stock. British Waterways recovered just under 2000lb of fish from a reservoir of 60 acres. The majority of stock were fish of over 2 lbs in weight (cormorant proof fish). Now to some that don’t know about stock levels of a naturally stocked water, which Elton was, it has never had any stocking into it since it was built back in the 1800, might seem a lot of fish. Well it isn’t the EA, Institute of Fishery Management and The Freshwater Biological Association through their many years of research, say such a water for its size and depth should contain between 350-450 lbs of fish per acre. Source - Freshwater Forum, publication of the FBA
Do the maths!
Elton until the cormorants showed up in the numbers they did 90s 00s was one of the finest fisheries in the NW. With many recorded catches of fish in many matches of a total weight for the whole match of over 1000lb.

You make reference to carp being destructive and destroying aquatic vegetation by eating it. First and foremost they rarely eat weed, what they do is, grub plants up to get at the invertebrates in the rootstock. Where they are highly stocked over 100lb an acre, then yes they can cause problems to aquatic vegetation. Under that stocking level there is no evidence of damage. See Prof Brian Moss’s papers on the subject. Starting in the early 1970s through to the present day.

Anglers stocked Zander, Wels catfish and Rainbow Trout.
Well zander were first stocked by the then East Anglian River Board into the Fens not at the request of Anglers I’d add. But as an experiment by the biologists who worked for them. The angling clubs of that region expressed concerns at the time about it. And were reassured by the biologists they would never breed in the Fens. Yep they got it wrong didn’t they!
Wels cats originally stocked into Woburn Abbey by the owner back in the 1900s as a sports fish for himself and guests. Stock for hear transferred to other waters in the locality over the next 40 or so years. And how widespread do you really think they are? Well nowhere near as you are thinking that’s for sure!
Similar situation with rainbows stocked as sport fish in the 1800s

As for crayfish …. Nop not down to anglers that, imported originally as a commercial cropping food source, surreptitiously seed by commercial trappers into other waters up and down the land.
Some evidence that they are being transferred by pleasure boats in the ballast water in them.

And Conservation bodies haven't done things wrong?
Ruddy Ducks,
Canada geese,
Arabian Oryx captive bred here and released back into to the deserts where they belong, most broke their legs because they'd only been use to running on hard ground.
Groundwork in it early years when replanting or creating new woodlands planting them up with non-native species. Italian Alder comes to mind
It very easy to look back with today’s eyes at yesterday and say that shouldn’t have been done. Tomorrow’s eyes will look back at today’s Conservation work and say Should they have done that?

Conservation and fisheries management are not precise sciences, they are evolving sciences and will continue to evolve as knowledge and understanding advances.

As to fish farms and their emissions, angling and anglers have been in many cases the only critical voice to the authorities about what comes out of them.

In defence of the Angling Trust they have never called for a cull of otters. What they have done is highlight that in “some” areas they are causing a problem and sort to work with NE, EA, OTs and WTs to find practical solutions to allow the animals thrive nationally.

Mr White are you not being somewhat unfair to sites and their members when you say anglers would like to see otters culled to improve their fishing. Fishingmagic the largest, has a poll where currently 72 % of the respondents have said they don’t want a cull of otters. Others, Northern Monkeys whilst not having a poll, but many threads about it, much the same, if you analyse the posts.

[Ukwildlifeo]

Originally Posted by Aquaticus

It strickes me that your posts says more about you and your attitude to Angling. One that reads to me as an anti bias against it.

Funnily enough I've been known to fish and I'm not against it. As I've said before on this thread a lot of anglers do good work with rivers and water bodies in general. My issue is when a lake is managed just for the fish at the expense of the wildlife. when a lake is dug specifically for fishing, fine, but when a angling club takes over management of lake in a country park and dredges out all the vegetation, as has happen recently in a lake in the Langdon Park complex, is where I have an issue. And having seen a number of dead birds hanging from trees in fishing line and hooks in waterfowls mouth tarnishes my view somewhat I'll admit.

Originally Posted by Aquaticus

So I'd like to look at some of the points you've made above.
You stated, "the latest research I read showed that a lake in a natural state (ie with lots of vegetation) which has plenty of shelter, there was no decline in fish stocks despite visits by cormorants, herons and otters."
I note this is not cited by you, so we, must, because you've read it, accept it unquestionably? References please?

I cant find the full pdf on my hard drive. I believe this is the paper I was talking about.
Effects of fish-eating birds on freshwater fish stocks: An evaluation 10.1016/0006-3207(88)90019-5 : Biological Conservation | ScienceDirect.com

There is this one too
Long term effects of cormorant predation on fish communities and fishery in a freshwater lake - Engstr[]m - 2009 - Ecography - Wiley Online Library

Originally Posted by Aquaticus

Well not really, because in such a nondescript state, it fails to answer many questions. Not least, at what time of year was/were the studies carried out? An important question you’d agree, as someone who’s interests are listed as wetlands, amphibians and reptiles.
You would know that I’d have thought, as much of the aquatic vegetation both marginal and submerged dies back or off during the winter months. And in which part of the year are cormorants in greatest numbers? Yep the winter! The birds start to return from September onward reaching a crescendo of numbers from December onwards until early March. This just happens to coincide with the greatest loss of fish hiding habitat, leaving the stocks readily open to predation by them. It also coincides with the greatest clarity of water, in stillwaters.

Although submerged plants do die back there is usually a fair bit in deeper (but in the littoral) parts of lakes to provide shelter, at least in decent lakes.

Originally Posted by Aquaticus

Mark Lloyd has explained cormorants are not a native inland bird in the main, but due to over fishing the seas and coastal waters have been forced to seek food inland.
40 years ago it was rare to record seeing them on inland waters. Not today though!
The enforced inland migration for food has decimated many inland waters of their native stocks of fish.
Elton Reservoir Bury is a case in point - when it was drained and electrofished to remove the remaining stock. British Waterways recovered just under 2000lb of fish from a reservoir of 60 acres. The majority of stock were fish of over 2 lbs in weight (cormorant proof fish). Now to some that don’t know about stock levels of a naturally stocked water, which Elton was, it has never had any stocking into it since it was built back in the 1800, might seem a lot of fish. Well it isn’t the EA, Institute of Fishery Management and The Freshwater Biological Association through their many years of research, say such a water for its size and depth should contain between 350-450 lbs of fish per acre. Source - Freshwater Forum, publication of the FBA
Do the maths!
Elton until the cormorants showed up in the numbers they did 90s 00s was one of the finest fisheries in the NW. With many recorded catches of fish in many matches of a total weight for the whole match of over 1000lb.

Thats quite bad I agree, I hadn't read that one. Do you have access to the pdf? looks like an interesting read.

Originally Posted by Aquaticus

You make reference to carp being destructive and destroying aquatic vegetation by eating it. First and foremost they rarely eat weed, what they do is, grub plants up to get at the invertebrates in the rootstock. Where they are highly stocked over 100lb an acre, then yes they can cause problems to aquatic vegetation. Under that stocking level there is no evidence of damage. See Prof Brian Moss’s papers on the subject. Starting in the early 1970s through to the present day.

I was going to say I didn't say carp ate plants them but I see I did. Must check what I write!

The information about carp grubbing up the bottom was brought to my attention a few years ago by an angler none the less moaning that they are introduced by/for '-expletive- carp fishermen' at the cost of other 'real' fishermen who want to fish other species as well. On the point of the stocking I agree, the point I was making that many lakes are over stocked and therefore the carp cause the problems

Originally Posted by Aquaticus

Anglers stocked Zander, Wels catfish and Rainbow Trout.
Well zander were first stocked by the then East Anglian River Board into the Fens not at the request of Anglers I’d add. But as an experiment by the biologists who worked for them. The angling clubs of that region expressed concerns at the time about it. And were reassured by the biologists they would never breed in the Fens. Yep they got it wrong didn’t they!
Wels cats originally stocked into Woburn Abbey by the owner back in the 1900s as a sports fish for himself and guests. Stock for hear transferred to other waters in the locality over the next 40 or so years. And how widespread do you really think they are? Well nowhere near as you are thinking that’s for sure!
Similar situation with rainbows stocked as sport fish in the 1800s

I'll hold my hands up admit my comments on zander where obviously based on an inaccurate book. Or was a case of being introduced supposedly 'for' anglers against their wishes if you know what I mean and this book just wasn't very specific?

Originally Posted by Aquaticus

As for crayfish …. Nop not down to anglers that, imported originally as a commercial cropping food source, surreptitiously seed by commercial trappers into other waters up and down the land.
Some evidence that they are being transferred by pleasure boats in the ballast water in them.

They may not have originally introduced them but many recent escapes to rivers have come from fisheries. My point is they are not helping.

Originally Posted by Aquaticus

And Conservation bodies haven't done things wrong?
Ruddy Ducks,
Canada geese,
Arabian Oryx captive bred here and released back into to the deserts where they belong, most broke their legs because they'd only been use to running on hard ground.
Groundwork in it early years when replanting or creating new woodlands planting them up with non-native species. Italian Alder comes to mind
It very easy to look back with today’s eyes at yesterday and say that shouldn’t have been done. Tomorrow’s eyes will look back at today’s Conservation work and say Should they have done that?

Conservation and fisheries management are not precise sciences, they are evolving sciences and will continue to evolve as knowledge and understanding advances.

Conservation bodies are not perfect agreed. Some of the stuff done recently by a certain big conservation body locally I would certainly question!

Originally Posted by Aquaticus

As to fish farms and their emissions, angling and anglers have been in many cases the only critical voice to the authorities about what comes out of them.

No argument from me, often the first to report sewage release by water companies too
(The ridiculous fines that don't deter them from doing it, now there is some definite common ground!)

Originally Posted by Aquaticus

In defence of the Angling Trust they have never called for a cull of otters. What they have done is highlight that in “some” areas they are causing a problem and sort to work with NE, EA, OTs and WTs to find practical solutions to allow the animals thrive nationally.

Mr White are you not being somewhat unfair to sites and their members when you say anglers would like to see otters culled to improve their fishing. Fishingmagic the largest, has a poll where currently 72 % of the respondents have said they don’t want a cull of otters. Others, Northern Monkeys whilst not having a poll, but many threads about it, much the same, if you analyse the posts.

In my defence i did say 'some of the Angling Trusts members.' Just had a look on the Fishingmagic forum and its heartening to see most don't support the cull, but some ignorant comments on that thread too from pro cullers (red kites eating songbirds!?). I remember being surprised by the outcry against otters at the time and googled some forums and the attitude of some anglers towards anything that eats fish is shocking.

Too some up my point was while anglers do a lot of good work, they do cause problems for wildlife, which is what I object too. I am certainly not against fishing

[Aquaticus]

Originally Posted by Ukwildlifeo

Funnily enough I've been known to fish and I'm not against it. As I've said before on this thread a lot of anglers do good work with rivers and water bodies in general. My issue is when a lake is managed just for the fish at the expense of the wildlife. when a lake is dug specifically for fishing, fine, but when a angling club takes over management of lake in a country park and dredges out all the vegetation, as has happen recently in a lake in the Langdon Park complex, is where I have an issue. And having seen a number of dead birds hanging from trees in fishing line and hooks in waterfowls mouth tarnishes my view somewhat I'll admit.



I cant find the full pdf on my hard drive. I believe this is the paper I was talking about.
Effects of fish-eating birds on freshwater fish stocks: An evaluation 10.1016/0006-3207(88)90019-5 : Biological Conservation | ScienceDirect.com

There is this one too
Long term effects of cormorant predation on fish communities and fishery in a freshwater lake - Engstr[]m - 2009 - Ecography - Wiley Online Library



Although submerged plants do die back there is usually a fair bit in deeper (but in the littoral) parts of lakes to provide shelter, at least in decent lakes.



Thats quite bad I agree, I hadn't read that one. Do you have access to the pdf? looks like an interesting read.



I was going to say I didn't say carp ate plants them but I see I did. Must check what I write!

The information about carp grubbing up the bottom was brought to my attention a few years ago by an angler none the less moaning that they are introduced by/for '-expletive- carp fishermen' at the cost of other 'real' fishermen who want to fish other species as well. On the point of the stocking I agree, the point I was making that many lakes are over stocked and therefore the carp cause the problems




I'll hold my hands up admit my comments on zander where obviously based on an inaccurate book. Or was a case of being introduced supposedly 'for' anglers against their wishes if you know what I mean and this book just wasn't very specific?



They may not have originally introduced them but many recent escapes to rivers have come from fisheries. My point is they are not helping.



Conservation bodies are not perfect agreed. Some of the stuff done recently by a certain big conservation body locally I would certainly question!



No argument from me, often the first to report sewage release by water companies too
(The ridiculous fines that don't deter them from doing it, now there is some definite common ground!)



In my defence i did say 'some of the Angling Trusts members.' Just had a look on the Fishingmagic forum and its heartening to see most don't support the cull, but some ignorant comments on that thread too from pro cullers (red kites eating songbirds!?). I remember being surprised by the outcry against otters at the time and googled some forums and the attitude of some anglers towards anything that eats fish is shocking.

Too some up my point was while anglers do a lot of good work, they do cause problems for wildlife, which is what I object too. I am certainly not against fishing

Thanks for the refs unfortunately I don't have access to the full text, so can only read the abstracts. Accepting this, the Swedish report I would assume is referring to Inland cormorants Carbo sensis as it refers to a breeding population. Not Carbo carbo the coastal birds, which is the majority of British birds that come inland to over winter.

The second seems to relate to a Heron study done in the 80s.
There may be a relevance issue with these studies to what's happening in the UK, and a more relevant study to the UK are the 4 volumes of study carried out for MAFF and DETR by Feltham M J et al 1999. Hughes B et al 1999. Wernham C V et al 1999. Makay H et al 1999. Sorry can't give you a web ref for them as mine are in hard copy.

I'd have to disagree with your comment about some vegetation being left as a meaningful hiding refuge for fish. Having studied many 10s of water up and down the country from farm pond with no fish, to large natural meres with native populations of fish, and all those in between -Canals, gravel pits, reservoirs large and small and rivers. Even waters that have species such as canadian pond weed which is prolific in the summer, only have marginal growth during the winter to a height of no more than 3-4 inches. That is not enough for roach, rudd, perch, small tench to hide in. Also such water go crystal clear at this time as I referred to earlier during the highest predation period.

As to Elton Reservoir, it was a pers com. I was tipped off about it from a friend who lives very close to it, who knows I have a particular interest in the water and was concerned about what would happen to the stock that was being taken out. I made contact with BW officers by phone to establish what would happen to the stock. In the conversation I asked about the poundage they'd taken out.
The Bury Times carried the story about the removal of fish, but didn't give the poundage recovered. That was some time in 2009 during the winter.
The same friend also spent all day watching the recovery and said he was totally shocked at the lack of small fish under 8 inches and the actual number of bigger fish they captured.

As to overstocking with carp that does happen on some waters. In the main, those water are what are known as commercials built usually by the owners for making profit. No fisheries consultant worth their salt would recommend to any club with a natural or semi natural water to stock at the levels a commercial water is stocked at. All the colleagues I know would recommend a stocking level of 100-150 lbs per acre and that would be dependant on the size of the fish to be stocked.

Re the Country park lake where you live, that frankly is bad management all round. Its bad management on the part of the Local Authority/CP for not writing into the lease agreement what the controlling club can and can not do.
It's bad management on the part of the club for not seeking professional advice on weed control and management for the whole water environment.

I can tell you now, the two clubs I'm a member of, both of which are very large clubs, many thousands of members, would never allow that to happen. They would always seek advice from a professional. I know because it's usually me who get the phone call and the conversation about any plans regarding these matters.

There's really no excuses in this area as the EA give free advice to clubs on all aspects of fishery/water management.

Just a thought, does the CP lake have a lot of Canada geese on it?

Angling is broad church of people and yes there are those in it with as you say are entrenched and shocking views. It's up to those within angling with, let say, more enlightened views to educated them.

The same goes for discarded tackle and litter. No excuses, if they're caught ban them from the club, water, preferably the planet!
But as that broad church, it does reflect the current view in wider society and that is a dirty one!

[Cakey]

well off topic now but I have fished for 50 odd years ,Im now 61 so Ive seen life as they say ,I fish and have always fished at least twice a week ,being self employed allows this .
I have never ever see birds tethered to trees with fishing line but dont doubt it happens.
I suggest youngsters fishing park lakes probably dont help as there are lack of teaching facilities and those that are around want paying ,I think clubs and water owners have a responsibility to teach .
litter is another big problem the clubs I belong to have litter bailiffs ,one of the clubs has rules of that I have to take litter home out of my swim even if it isnt mine.
the same club does not allow me to take cans or glass bottles on to the bank with me.
I also fish a place called The North Met which is owned and run by Lee Valley Parks this has a real big litter problems but its used by anglers ,joggers ,cyclist ,dog walkers , bird watchers, walkers and duck feeders and by the rubbish I have picked up they are all capable of leaving rubbish ,I would love to meet the dog walkers that pick their dogs poo up but then tie the bag to the nearest tree !
right im off now to walk the dog and do a litter pick

[Burko]

Whilst doing an otter survey last year I found several mussel shells, with fresh otter tracks leading right to them and fresh spraint nearby. Very simple to decipher.