How many fish are out there

[Philip]

Watched an interesting documentary about Great white Shark. One point that really stuck with me was that it said rather than consider all the GW shark around the world as separate groups there was evidence to suggest it was in fact just one Global population that travelled around.

This was backed up by the fact they tracked one female Shark that swam from South Africa to Southern Australia and then back again…they are not sure why but they think breeding may have been the driver. I heard a similar story of another tagged fish (cant remember the species) that crossed the entire Pacific and then swam all the way back again.

It made me wonder how much this is happening on a smaller more “local” scale with our own fish ?

In the case of the GW shark it certainly made me consider just how fragile ecosystems could be if you start taking individuals out of it.

 

[steve2]

Repeat captures on rivers give a false impression of stocks. I have caught the same fish upto a mile apart on a small stream. A Pike on the Suffolk Stour I recognised as being over 2 miles from where I first caught it. Carp these days are always being recaught which give a false impression of big fish.

 

[mikench]

This is interesting.

Scientists say they've cracked the mystery of why whales migrate—and it's all about healthy skin

Whales travel to the tropics to molt

www.sciencemag.org

 

[theartist]

One of the stretches of canal I fish is shallow and this year due to lockdown has been pretty clear As a result you can see the fish. There's resident shoals that winter under the bridges etc but what is noticeable is there's is a large shoal of bigger roach, bream and hybrids that travel up and down this section, some times you get a fish and the rest are gone and often you see them ghosting through disinterested. I once tracked them(not fishing) all the way to the next lock before they went the other way heading back. When they are spread out in summer it makes for even fishing where it would seem the canal is full but in winter you could miss them completely

Similar on the Severn, I was roving and had a couple of barbel on the float when the feeding bubbles appeared beyond casting range, they seemed to go upstream and sure enough by tracking them I picked off another couple before it got to a busy section where the swims were taken, I sat down having already had a good day and heard buzzers and clutches screaming a few minutes later as this shoal was passing through, it would have been their witching hour where the fish had 'switched on' but in truth they were passing though. It was broad daylight and these fish had already gone a mile before I stopped and left them to it.

Often you can see fish feeding and it only takes a small shoal of fish to give a bite a chuck, and where the water is coloured you would think they were everywhere and other times you feel that they really are everywhere, especially fish like gudgeon and bleak, sometimes you can see the shoals and they can be colossal. Good thread Philip I've been wondering just how many fish are in the confines of a narrow canal and still can't gauge it so good luck to those who want to be specific in the pacific.

 

[Philip]

I have seen similar Rob, in clear water with shoals moving up and down and you watch as they pass an angler who suddenly gets a flurry of bites and then it goes dead again as the shoal move on.

I guess what makes a shoal stop is important to us anglers. To my mind its one of three things…Shelter so a holding spot, breeding urge or food. Predation is possibly a forth one.

The one we can influence the most as anglers is obviously food. If those anglers remembered to feed as the shoal passed them they would probably catch more than they do.

Some Thames Carp have been seen to move long distances one known fish moving through 16 locks to be caught in 2 different places. Of course anglers shift them around as well but fish are great travelers in their own right. I think its Dace that were also shown to move silly distances up and down rivers.

Like allot of us I imagine, I occasionally catch the same fish. Obviously, I prefer to avoid recaptures but I also look at it when it happens and think – well at least that proves I put it back ok last time.

 

[theartist]

We can only suss the repeats if they have unique markings, I imagine those of us that don't use keepnets are catching more repeats than we realize. Like you say they seem happy to feed again, I sometimes think they know the score at times and if returned quickly and carefully can perceive the risk of being caught again outweighed by the opportunity to feed when times are tough, be it through lack of food due to the weather or competition from other fish.

 

[dorsetsteve]

I met two chaps the other week pike fishing, 50-100 yards apart. Both had caught long skinny 14lbers, so they told me. I wondered if they’d both caught the same 14lber, probably.
If you can work out when fish move into an area, they often follow that like clockwork.

 

[mikench]

I'm an Orca fan having seen them in their natural environment in many places. Different pods will specialise in catching fish, others mammals like seals and other dolphins and others sharks , penguins and sea lions. A healthy adult will eat 385lb of salmon a day in the Pacific off the coast of Oregon and Vancouver. That's a lot of salmon .

 

[john step]

Great Whites. I saw a documentary once that showed the jaws of GWs hung on the wall of cafes in Greece of all places. Apparently they were common there feeding on harp seals. Once the harp seals were hunted to extinction the GWs disappeared too.
I seem to recall it was before the boom in tourism and the language difference hid them from the outside world.
I suppose there would be plenty of food nowadays for the GWs when tourism starts again.

Repeat captures. Does anyone else remember Fred J. and the other Taylor brothers with large catches of tench. ( It may have been Blenheim )
Frd J related that they didnt use keep nets until one day they use them to show the numbers of tench for some article or programme.
He related that they failed miserable once they started putting the tench in a keepnet hung over the side of the boat and it dawned on them that the previous large numbers of tench caught in a single session were in fact repeat captures.

 

[theartist]

Keepnets is another slant, on some waters you feel the keepnet can hinder big catches, whilst you don't get the repeats you also don't get fish returning to the shoal maintaining that safety in numbers, plus if they return to feed other fish will compete with them. It may work the other way on occasion so that's not set in stone just a theory.

Ps. Don't put a Great White in one

 

[steve2]

Repeat captures. Does anyone else remember Fred J. and the other Taylor brothers with large catches of tench. ( It may have been Blenheim )
Frd J related that they didnt use keep nets until one day they use them to show the numbers of tench for some article or programme.
He related that they failed miserable once they started putting the tench in a keepnet hung over the side of the boat and it dawned on them that the previous large numbers of tench caught in a single session were in fact repeat captures.

I would say that there is not a fish in the popular waters in this country be they day ticket,club or syndicate that have not been caught many times over. The angling news is full of repeat captures of large carp, barbel, pike, chub etc.
There are those that return to the same swims and catch the same fish just to boost their big fish numbers.

 

[Philip]

I told a story a while back about losing a couple of fish one evening in a river due to the line breaking. The next evening (which was June 15th) I sat it out till midnight to see the 16th in. I was holding my phone watching the seconds tick down to midnight and literally on the stroke of midnight (-and I do mean literally to the second-) I had a bite & hooked & landed a Barbel which had 3 hooks in its mouth..the one I caught it on and my 2 hooks from the previous evening.

Unbelivable odds of that happening aside, the point being that I had assumed 3 different fish were responsible for the bites and losses but in fact it was just the one.

 

[The bad one]

I think its Dace that were also shown to move silly distances up and down rivers.

Indeed they do and it was Dr Stuart Clough that found it out on the R. Frome. He radio tracked a dace and it moved every night around 6 miles up river, returning to the same spot it started from come the following morning.

 

[seth49]

Usually after I catch a carp, I take a quick photo of it, if it’s around eight pound or over, I’ve noticed I’ve caught them before, and often from the same peg, although they do seem to move from the shallow end of the pond in winter, one mirror carp I caught five times from the same few pegs last summer.

Even with the commons there’s some distinguishing mark which identifies them as a rule, most have lost a scale when spawning which grows back different to the rest.

 

[peterjg]

I think that there are more fish out there than we realise but it does seem that the same fish keep getting caught. Different presentation, bait and fishing time does (eventually) catch unknown fish. This especially applies to mirror carp which are so easily recognised. On a lake that I carp fished a great deal for many years I thought (guessed) that a third of the carp were easy, a third just ate natural food and that the last third were too sneaky and were uncatchable. This was on a 50 acre lake with around 200 big carp to 55lbs+. It would be great if the same applied to big roach - still trying!

 

[silvers]

I think that there are more fish out there than we realise but it does seem that the same fish keep getting caught. Different presentation, bait and fishing time does (eventually) catch unknown fish. This especially applies to mirror carp which are so easily recognised. On a lake that I carp fished a great deal for many years I thought (guessed) that a third of the carp were easy, a third just ate natural food and that the last third were too sneaky and were uncatchable. This was on a 50 acre lake with around 200 big carp to 55lbs+. It would be great if the same applied to big roach - still trying!

I’m more inclined to this POV, especially when it comes to rivers and canals that are more lightly fished. I’ve witnessed several occasions when the river suddenly “fished its brains out” when suddenly all species went on a feeding spree ... especially with roach ... which would suddenly appear in great numbers throughout a length.
This would be different to the annual migrations that happen with roach and dace.

 

[mjkobe]

that is out of my knowledge

 

[John Aston]

I helped the EA with some electro fishing on my local small beck a year or so ago . Even in a pool I know very well . I was gobsmacked at how many fish appeared , including a bloody great eel . Years since I've even seen one in the beck .

But I can think of some stretches of my local river where, compared to twenty years ago, electro fishing would probably be very slim pickings indeed. But that is just my guess - anglers tend to assume they know far more about fish population and behaviour than they actually do , judging by some of the crackpot theories I hear .

 

[sam vimes]

I'm absolutely convinced that repeat captures are far more common than most anglers would ever believe. I'm not just talking about longer time periods such as weeks and years. I've had repeat captures of carp, trout, grayling and chub in the same sessions. I've also witnessed the same carp and pike be caught twice in a day by different anglers. The most extreme I've had was the same trout caught three times in less than five hours. I promptly packed up and went home after that one.

The biggest snag in noticing these repeat captures is in finding something distinctive enough about an individual fish to recognize it. Many species of fish don't have features as obvious as distinctive scale patterns like a mirror carp. Sadly, most instances of me recognizing repeat captures have been with river fish bearing distinctive scarring or damage from predators.

 

[steve2]

If you read big fish lists of carp, pike, barbel, you will see many repeat captures. In some books by well known anglers their big fish list contain repeat captures caught 2 or 3 times they seem to count these repeats and add them to their list of big fish. Instead of one 30lb pike or carp it becomes three 30lb fish.
A bit misleading when counting the number of big fish in a water.