A Lower Thames Fish Survey

Environment Agency Fisheries Officers have been carrying out surveys along the river Thames and the TAC were invited to help on the processing boat. We have built up a strong relationship with the EA over sometime now and were obviously delighted to accept the invitation and report back from the day adding some great fishy pictures.

The fish survey is carried by out using a specially designed boat which has two arms extending from the front passing an electric current through the water. The current runs from an anode to a cathode which attracts the fish and momentarily stuns them. Once the fish are stunned, two of the fisheries officers net and place the fish in a holding tank.

The electro fishing is done over a timed period, on average today it was around 30 minutes. The time coupled with the number and size of fish caught will give an eventual result of the survey.

The processing boat has the job of measuring each and every fish caught, recording them by species and taking scale samples with specific ranges. The scale samples are taken to scientifically calculate the year class and growth rate of the fish. Knowing this information gives the EA a clear picture about specific reaches and can assess why there maybe fluctuations. Issues such as abstraction, flow rates, pollution can all make a difference so the surveys are vitally important to the future health of the river. In addition the surveys will influence restocking, questions about habitat restoration, spawning areas and much more.

We set off in the processing boat around 6.45am, a little while after the boom boat giving them time to catch the first batch of fish. At an agreed point the processing boat was tied up and the boom boat came along side and we moved the fish into the holding tank.

Most river species were present with Roach making up a very high percentage of everything caught. The density of other species varied from reach to reach. First batch for example only a handful of Gudgeon, then the second huge amounts. The expected Dace were there but not in large numbers compared to the masses of Roach, same with Bleak. The Roach ranged from around 30mm up to around 200mm, nothing very big but by far the dominant species.

Perch were present in all sizes and also Pike from stunning juveniles to some much bigger specimens. With the Pike they all seemed to have solid bellies and looked like being hard on the feed at present, this was also borne out by silvers that were been caught with slices out of them.

Juvenile Chub seemed low in number but were delighted to see a few bigger fish in superb condition. Barbel were netted in a reasonable numbers, this included some young fish which was great to see. Having caught 'stockies' before, none of them were dye marked so Thames bred.

At each point Eels came out from bootlaces to dark bigger fish around 1-2lb. One very special Silver Eel was netted around 3-4lb mark, Silver in colour meaning it was on a long journey to the Sargaso Sea.

Huge thanks goes to Dan Horsley and the team for inviting us along. Be under no illusions just how hard these guys work as spending the day measuring and recording each fish takes time and effort as I found out.

So the day in pictures, Dan with most of the fish

Boom boat in action



The electrodes



First big fish of the day, 23lb 5oz



And something a bit smaller



Juvenile Barbel



Bigger Barbel





An Eel being measured



Chub being measured and a scale taken



The scale to be sent for analysis



The Chub, 5lb 8 oz



Measuring the vast numbers of fish caught



Perch just shy of 3lb



Another nice Chub




Thanks again to Dan for the invite and all involved at the EA.

some stunning pics, thanks for putting these up

after that mini pike and barbel!

Great post David!

Can you tell us about the distribution of where the fish were caught? For example what did you find in the margins as opposed to in the middle of the river? Did you catch the barbel and pike in the weir pool etc?

Regards,
Stephen

Matt Johnson wrote:

after that mini pike and barbel!

Yeah they're the best of the bunch, very encouraging.

And all those mini roach means pred fishing should be good for years.

As has been said, great photos and good to see small Thames bred Barbel amongst the 'captures'

Was great to see so many juvenile fish, out of all there must have been 20+ baby Pike, very healthy.

Stephen the Barbel mainly came from oxygenated water but everything else was widely distributed. The boom boat zig zags across the river so covering areas that maybe deep pilings to shallow gravels. Bigger Perch certainly from the deeper area and Chub on clean gravel. So not any great surprise in the type of habitat, just showed that if you are targeting a specific species, look at where they should be, think thats what I learnt.

As said on the other thread I helped on the processing boat which measures each and very fish that is netted, and believe me there were very very many samples.

spent the morning with the EA at Hamton court bridge, some nice chub were caught, 6Lb +, a nice carp, mybe 20Lb, lots of pike, up to 12Lb, 3 eels up to 3Lb!, and 3 flounders, only 6" long, no trout were got, but I saw two just swimimg by 30mins after they had finisted, 10" + long, one barbal was got, around 10Lb

















got me location wrong

Flounders at Walton

Furthest we'd ever heard them get upstream is Hampton Court. Amazing really.

EDIT TO SAY Keith changed the details...it was done at Hampton Court and not Walton so the flounders haven't set a new record after all

the more i see, the more i want!

bit of a 'ghostie' sheen on the small common

the thames is a truely magical place and long may it be so

what an enjoyable thread, some of tose fish are fin perfect

that is a lovely perch, anybody got his address?

you swash bucklers and your boarding skills
good on ya keith for getting down there and offering to help, if I'd known there was a space I'd have grabbed it myself

Interesting that there didn't appear to be any bream.

Maybe all that slime insulates them from the electric !

Dave/Keith - question for you...

When barbel, chub and perch popped up to the surface, did they come up in shoals or as single fish?

I'm wondering at those sizes we see in the pics, some being very mature fish, what size shoals they were in?

Also, did they mention at what depth does the electro stop having an effect?

The mature fish were the exception and mainly single fish. At each stop I estimate around 300 fish were netted and the vast majority were small, that is of all species bar Gudgeon which were a more or less the same size.

So yes shoals, but not of big fish.

Perch were seen in different sizes, so from tiny through to a few ounces, a pound then up to 3lb+

Barbel (as you will find out) tend to be nomadic and seldom have found them in shoals bar when its flooded.

Incidentally, asked the question about tidal electro fishing and the reason why they are not done is salt water does not conduct electricity as well, so a much higher and potentially harmful would have to be used.

sorry keith, had to edit m8, to much info for poachers



the electro machinery has a range of around 3', outwoods and down, they do all/most of the fish finding in shallow water,

apologies keith, but had to edit your picture

the information available in this pic is available by pm only
the reason is the risk of poaching/netting
I apologise to everyone for my knee jerk reaction, but better to be safe than sorry

please engage in some discussion as to whether this is the right course of action, and admin will follow your instructions

Electro fishing results, they've gotta be in the public domain, the locations of the survey and catch photo's are already abvailable anyhow. So fair enough, thanks for publishing Cap'n, this kind of detail is invaluable for us beginners!

Sadly the results are seldom available mate, locations I dont believe are ever given?

Have to think about how much poaching and illegal methods are rife on the Thames, could give an open invite.

Just my personal opinion

There is another aprt of the survey process which I get posted up when time is available

David Harvey wrote:

Have to think about how much poaching and illegal methods are rife on the Thames, could give an open invite.

Exactly what I thought mate. Even the level of detail in Keith's last post could be too much. Dave's call but maybe make it available to people known to admin, thru being at litter picks, events etc?

There's a lot of people on this forum we don't know, who come on once or twice and then that's it. We need to at least consider if we want having them that detail of info.

Was only last year we heard that stretch was being netted at night...

admin has info from last year, and some topography and fish density info that could make anyone a superstar
as such it is available to no-one, admin has agreed to not look at it or make use of it, hence admin dont catch much
thats whats fair for all, so alls fair


I edited keiths posts, and wanna know your opinions please chaps

if i ask the EA regarding the river roding they always supply me with the results of electro fishing stating when and where it was done. keith made a point about shallow water, the last time passingford bridge was surveyed in 2007 in was in 5ft to 9ft. hope the thames survey was less sole destroying as ours are in sx

Me personly and for wot I stand for, Magna Carta 1215, and all that, freedom of speech and information, any info I get, unless told other wise, by the person/s I got it from will allways be made freely available, I am not into any secrete meetings or secrete clubs, locations, the River Thames up to Staines is free fishing, if any information gets into the wrong hands, that is the chance I will take, but this is not my web page, so the owner has the right to edit things out, if he fills it is apopoate,

if things start being put into the not for public domain file, people will start wondering what we stand for

that is just my opinion,

James Page wrote:

I edited keiths posts, and wanna know your opinions please chaps

You did the right thing Jim. You and Dave get to hear from the EA about poaching/netting.

Keith your info is still freely available to those who want it - they just need to PM admin.