richiekelly
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So would i..........
cracking bag of barbel!
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So would i..........
chub_on_the_block
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Apart from anglers bait, i struggle to think what they would eat -bloodworms?. In a clean fast flowing river theres a massive range of caddis and small molluscs to grub around for, often at incredible densities.
A point made earlier in the thread was that if you introduce barbel to a river they will leave less food for other fish (eg roach) so a lot of barbel would cause a knock-on reduction in something else. Strictly speaking this effect would only happen if resources are limiting. If resources (food,space, oxygen) were not limited then there need not be an effect.
A point made earlier in the thread was that if you introduce barbel to a river they will leave less food for other fish (eg roach) so a lot of barbel would cause a knock-on reduction in something else. Strictly speaking this effect would only happen if resources are limiting. If resources (food,space, oxygen) were not limited then there need not be an effect.
cg74
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Yes Fred, they are my opinions (assumptions as you put it) but unlike yours, mine are derived via science and reasoned logic, can you show me evidence to the contary then; that barbel do not have a negative impact on any indigenous species of fish already present.
Its not like an ailing river can have its ills rectified by the inclusion of barbel to its resident fish, or am I wrong?
The reason for stocking any fish into an alien environment is simple (whether or not the environment is suitable is an irrelevance), its to suit the selfish needs of those responsible for the stocking.
Fred, with the greatest respect, I suggest you do some reading-up on the impacts of introducing alien species into ecosystems where they're likely to 'thrive.'
---------- Post added at 03:27 ---------- Previous post was at 03:23 ----------
Seems some see only what they want to see......
chub_on_the_block
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Proving a negative or null hypothesis is always hard work. Better to prove the positive - that they have they had an effect on pre-existing fish stocks to disprove the null hypothesis..
sam vimes
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It bemuses me that so few can see the hypocrisy involved in thinking that stocking into rivers where fish aren't indigenous is somehow OK yet stocking into stillwaters is the work of Baelzebub. It's quite fascinating how people go about justifying this inconsistency of thinking. It's either wrong to stock in such a manner or it's not, there's no grey area as far as I'm concerned. I'm afraid that there's absolutely nothing that anyone can say that will convince me, I simply don't buy it. However, I'm not on a high horse over the stocking of either stillwaters or previously non-barbel rivers.
chub_on_the_block
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I see it like this: Stillwaters are unsuitable for the species. They are barely within range of conditions that the species can survive in and outside the range in which it can sustain populations naturally. Barbel are poor swimmers with small swim bladders and high oxygen demands and might be physiologically stressed by life in a stillwater.
As for rivers, this is more of a river management debate rather than fish welfare. The two issues are separate in my head at least.
Yes i would like to see rivers support naturally balanced fish populations and i do think there is an issue if they are all being stocked with barbel, rainbow trout or whatever. In the case of the Severn and Ribble Barbel though, which are suitable, i dont see an issue. I have long given up hoping for lakes with naturally balanced fish populations as these may be privately owned or created solely to provide recreational fisheries - that would be like dictating what people do with their garden ponds.
Judas Priest
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I'd agree wholeheartedly with your post Sam.
Bit like the hypocrisy of those who so vermently and loudly support the retention of the Close season on moving water, citing the effects on spawning fish and the environment, yet are quite happy to tell the world how they target spawnbound fish on stillwaters during March to June.
To use the excuse that it's ok because the waters are open and they can't change that situation is pathetic as in the main a lot of those same anglers are against the stocking of stillwater barbel yet both situations arise because of anglers "needs", not any ethical or conservational considerations.
---------- Post added at 11:20 ---------- Previous post was at 11:15 ----------
sam vimes
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I've seen your arguments before and while I can see the thinking I just don't accept it. Stillwaters being barely suitable for barbel is highly debatable. They can't breed in stillwater is trotted out as a fact. What about the stillwaters where there's some (undoubtedly highly debatable) evidence to the contrary? Why if stillwaters are so unsuitable are people remotely concerned that a future "record" barbel will come from one? Surely if they are so unsuitable then there's nothing to be worried about? If stillwaters are so unsuitable then why are the commercials continuing to stock barbel? You'd think that them going belly up every five minutes would put them off somewhat. What about the fact that the barbel commercial stillwaters are stocking are farmed fish, farmed in still, albeit aerated, water?
If fish not successfully breeding was a bar to future stocking why is the EA restocking barbel into rivers where they aren't indigenous and they don't self sustain? The sad fact is that there seem to be fewer and fewer waters, still or flowing, that do actually self sustain these days.
I don't dispute that the likes of the Ribble and Severn have proven to be eminently suitable for barbel and are definitely more so than any stillwater. However, even if it was a geological accident, that's not a valid argument for interfering with what has occurred naturally. It wasn't a man made pollution incident that lead to there being no barbel in such rivers. It isn't a re-introduction. Evolution and the distribution of a multitude of species is full of geographical accidents. I fail to see how it is more correct to interfere with such accidents.
You can't complain about it being unnatural to stock barbel into stillwaters while turning a blind eye to equally unnatural stockings in rivers such as the Ribble.
chub_on_the_block
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I assume they are responding to local demands from anglers or clubs which believe that populations have been depleted, perhaps by pollution incidents or by otters or maybe by fish migration out of their reach. I would not be rushing to re-stock if it was up to me. If the barbel cant sustain populations in the face of natural factors than they should not be there. If they should be there but cant, then i would look to find out why - perhaps the river needs habitat restoration work due to previous flood defence works or whatever. If the river is naturally unsuitable they should not be there!
---------- Post added at 04:47 ---------- Previous post was at 04:39 ----------
Sam i think you talk a lot of sense and i am generally in agreement with what you post - infact you have put me right on more than one occasion. However, I still have trouble with putting a riverine fish into stillwaters. I guess i do not trust the research that apparently suggests they thrive there. Maybe there are local factors - these were northern waterbodies that may be cooler year round than a southern commercial. At what size were the fish stocked?. Etc. I dont feel as strongly about all this as my postings may suggest. If i did I would have topped myself years ago. Theres a lot about the modern angling scene that i find to be completely at odds with my traditional and rather old fashioned outlook. Not surprising as my views are perhaps like a time capsule from about 25 years ago when i last fished as i do now.
jasonbean1
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"But as is evident on the middle reaches of the Severn; barbel certainly rule the roost. Which to me is wrong!"
Love it!.....Colin whats your favourite barbel river at the moment
Love it!.....Colin whats your favourite barbel river at the moment
At the end of the day the only reason to stock barbel in any river is if they have been resident for many years and diminished through pollution or some other man made failure of the riverine environment.
Most if not all of the stockings in rivers where they weren't before are probably in excess of 40 years ago. so why some are still making a point of this puzzles me.
Can't be arsed to dig to deeply Colin, the fact is that individual rivers such as the Wye in their entirety still have good stocks of all fish, so to tar an entire river with the same brush is not got anything to do with science,it's here say much like any excuse an angler may use for not catching fish!
Most if not all of the stockings in rivers where they weren't before are probably in excess of 40 years ago. so why some are still making a point of this puzzles me.
Can't be arsed to dig to deeply Colin, the fact is that individual rivers such as the Wye in their entirety still have good stocks of all fish, so to tar an entire river with the same brush is not got anything to do with science,it's here say much like any excuse an angler may use for not catching fish!
sam vimes
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No doubt this is true. However, is a crime any less of a crime whether it happened forty years ago or yesterday? If stillwater stocking is worth denouncing then why are those that are so concerned not denouncing the stockings into non-indigenous rivers? In forty years time will stocking barbel into stillwaters have become acceptable to those that denounce it now?
I'm sure if people were aware of it going on they may well do Sam.
As for stocking of stillwaters, my guess is that it will not be condoned for the very reasons discussed, as it stands though I would suggest that perhaps it will be a fact of life so whilst not accepted a fait accommpli!
What you have to remember is that the original out cry related to barbel being "stolen" from rivers and stocked into fisheries!
As for stocking of stillwaters, my guess is that it will not be condoned for the very reasons discussed, as it stands though I would suggest that perhaps it will be a fact of life so whilst not accepted a fait accommpli!
What you have to remember is that the original out cry related to barbel being "stolen" from rivers and stocked into fisheries!
sam vimes
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That was certainly worth a hue and cry.
cg74
Well-known member
"But as is evident on the middle reaches of the Severn; barbel certainly rule the roost. Which to me is wrong!"
Love it!.....Colin whats your favourite barbel river at the moment
Hmmmm, let me think, seeing as I've no interest what so ever in chasing the Cherwell's few remaining barbel and I live 80 miles from the Wey, what with fuel prices etc, its not forgotten but is a little less favoured..............
...... Yep, its got to be the Windrush. [insert moony smilies here]
Now had you asked where I've been doing most of my barbel fishing this season, then the answer would have to be; the Severn.
Now that could be construed as hypocrisy and in fairness it is but I'd rather fish for a displaced fish than no fish at all.
I posted a thought on hypocrisy here: http://www.fishingmagic.com/forums/fm-news-feature-comments/258223-barbel-stocked-don-4.html
Fred, the fact still remains; by introducing another (alien) species to an environment, if said environment is running well, so too its full capacity of bio-mass, the new inclusion must edge out to degree one of the pre-existing species and due to the dietary similarities barbel primarily push out roach.
This may leave what you deem a good head of indigenous species BUT that is only opinion based, the fact is there would be more indigenous fish present if it wasn't for the artificial stockings by selfish men!
Just out of curiosity would you be happy if your favourite river was full of alien species; Signal crayfish, Asian carp, a few fan tails for colour?
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Still not sure about your definition of fact, not seen them anywhere.
Certainly not Colin, but they are truly alien species to the English rivers.
Certainly not Colin, but they are truly alien species to the English rivers.
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cg74
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Fred, just google search the effects of invasive species, read on, and you may learn?
So its fine for a species from one English river to be stocked into another where it is not indigenous too?
So what of good ol' Barbus barbus; proliferated from the Rhine into many of our eastern flowing rivers when Britain was apart of mainland Europe but seeing as Europe is part of the land mass that is Eurasia, why not Asian carp and fan tail kois etc?
Or even ide and wels catfish from Europe?
I suggest its selfish men with their own agendas, meddling with nature, for their own gains and tarting it up under the premiss of; nothing wrong with English fish being moved into other English rivers.
An awful lot of bowlocks being spouted on this thread, but this is by far the most important sentence so far.
Thank you for this injection of fact and wisdom Fred. I didn't want to be the one who said it.
chub_on_the_block
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I would have thought that roach feed heavily on drifting invertebrates, intercepting these as they pass (infact there is nice film of them in the Hants Avon somewhere doing just that). In areas of slacker water they may well be picking at weed or silt. Barbel will be hoovering and digging about, lifting quite large pebbles or stones for attached caddis etc. Whilst there may be dietary overlap, they probably exploit different areas and different types of prey. Barbel activity may infact make it easier for roach downstream of them to intercept dislodged invertebrates.
The biomass argument is simplistic. To out-compete other species for a resource (eg invertebrates) that resource would need to be the limiting factor. I really doubt that this would be the case. Invertebrate biomass can vary enormously over time (temporally) or from one patch to another (spatially). Only after a major spate where populations may be decimated is it likely to ever be in short supply in terms of biomass.
If a new fish species came along that ate a different food resource, that wasnt an existing part of the diet of the fish already present (for example a species which ate dead leaves, to think of something that is not part of the present food chain for fish in the UK) then the biomass of this new species would be independent of everything else (but could increase the biomass of predators upon it). This illustration just makes the point that biomass limits are not necessarily fixed. But as I said, if the supply of invertebrate prey is not a limiting resource, then this is irrelevant in any case.
The biggest threat to invertebrate biomass is probably signal crayfish. In waters where these are highly abundant there can be fundamental changes to the invertebrate community - massive loss of soft bodied caddis and sedentary animals such as molluscs.
The biomass argument is simplistic. To out-compete other species for a resource (eg invertebrates) that resource would need to be the limiting factor. I really doubt that this would be the case. Invertebrate biomass can vary enormously over time (temporally) or from one patch to another (spatially). Only after a major spate where populations may be decimated is it likely to ever be in short supply in terms of biomass.
If a new fish species came along that ate a different food resource, that wasnt an existing part of the diet of the fish already present (for example a species which ate dead leaves, to think of something that is not part of the present food chain for fish in the UK) then the biomass of this new species would be independent of everything else (but could increase the biomass of predators upon it). This illustration just makes the point that biomass limits are not necessarily fixed. But as I said, if the supply of invertebrate prey is not a limiting resource, then this is irrelevant in any case.
The biggest threat to invertebrate biomass is probably signal crayfish. In waters where these are highly abundant there can be fundamental changes to the invertebrate community - massive loss of soft bodied caddis and sedentary animals such as molluscs.
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Damian Kimmins
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Whoa there..................how do you explain a Lyre Bird's tail as a survival trait? It's the survival of the gene, not the individual.
Or a Bower Bird's bower?
Male Birds of Paradise?
Or any of a host of other amplified male adornments brought on through female sexual preference through evolution?
How do these traits enable survival of the individual animal? It's the genes.
If a higher dorsal fin enables male barbel to gain greater access to females at spawning, those genes will pass on and become progressively amplified, much as females can show active preference for particular traits that have no positive correlation to the animals general survival prospects.
A higher dorsal fin might enable greater manoeuvrability and then get selected purely on the strength of the act of spawning, not survival. As any number of species show, the adornment (the gene for it) can eventually outweigh it's physical usefulness.
Why else would male Narwhal have those "unicorn"-like horns? They have no practical survival function.
I thought you'd read The Blind Watchmaker et al?
An interesting riposte, Simon, but it's not the case. Species that express a preference for the more elaborate mating rituals or any adornments (sexual selection), number much much less than those that express a preference for the most physiologically advantaged for their environments. It tells the story animals that consider rituals important can do so through having filled a niche that allows them the time to evolve these rituals, when ordinarily it's the precursor to that, that of best adapting to their environments, that their time will be taken with.
Consequently, it wouldn't happen with barbel as I would imagine their environments (stillwaters or flowing) to be too fish species rich.
Like I said, a higher dorsal fin would have to enable greater manoeuvrability to be selected, certainly in the freshwater environment in the UK, and let's face it, their manoeurability is not going to be tested in some puddle is it?
I managed to get hold of a copy of the Angling Times today and to say that this is a study is completely misleading. From what I can make out it's the study of the results of a questionaire that has been sent to fisheries that have stocked barbel, not a study in barbel in stillwaters.
Damian