Lake devoid of smaller aquatic life

[philocalist]

Philo,

 

Interesting dilemma. How about the surrounding landscape? Not sure what SHOULD be there but over here I'd be looking for lob worms, grasshoppers, various and sundry leaf eaters, mossys, etc. You say the plant life about the bank is healthy, how about back 4 or 5 meters? Do you know if algae is ever a problem? I.e. big swings in water colour. If not DO could it be photosynthetic capacity? How solid is the bottom? Can you or has anyone seen fry feeding in the margins?

 

The identified "problem" is nearly impossible - yet I believe you.

 

Phone

Surrounding landscape is healthy enough Phone - many species of birds, rats(!), grey squirrels - very occasional deer but no rabbits. Get bitten often enough by flying insects later in the day, and usual suspects are around durng the daytime. No problems at all with bankside growth to the degree it needs constant cutting back / control. Bottom varies - mostly silty though not overly so - other areas are heavier mud and even clean gravel in places. Water clarity can vary vastly and quickly, though that issue seems to be explained by the action of water on the surface (or not) - prevailing winds keep suspended sediments etc moving, but they drop out very quickly if wind stops or starts to come from a direction where the lake is largely protected from it ... and no obvious problem with algal blooms etc. Apparently there were masses of fry visible a couple of months back, identified generically as silver fish - anything from less than a half inch to maybe 3 times that size, though not obvious now.

 

One possibility I'm considering is that an overabundance of smaller fish have stripped the lake of natural food, then subsequently been bullied off anything that later re-appeared by bigger fish, perhaps causing their demise. The few anglers who fish, often on a pole, frequently report many bites that they are unable to connect with, which may be very small fish which would register on a delicate pole rig but be too small to hook.

The problem with this theory, if correct, is that the remaining fish should be climbing up the line to get at bait, and they're not ... it's not an easy lake to catch on ... we've had bream to about 5 lbs, tench a bit bigger, and stacks of 3" - 6" silvers and perch, all apparently healthy, but it's very easy to fish there and blank!

[chesters1]

Sounds just like stockbridge except we have bunnies and a cat called atticus from next door after them.

Bottoms different though its silty one end but generally hard pack sand and ironstone in the summer algy forms about half and inch thick on bottom then pops up and floats off down the outlet ,the evidence the few carp visit the swims is noticable by the lighter patches where they disturb the algy.

Lots of fry as well but you never catch (as in 1" or so) small tench or crucians only perch and occasional small roach

Pond is stream fed but several other ponds are upstream so i guess the inlet is nutriant rich but oxygen low ,i have no way of testing mere bailiffs are just number collectors in farnham there is no interaction other than that or should i say we interact but are ignored

Place has perked up this year though a recent stocking of 500 6" tench has seen catches of all fish rise a bit i guess the balance of food has gone negative so the fish are looking harder and taking baits

 

http://www.farnhamanglingsociety.com/news-articles/video-Farnham-Angling-Society-Stockbridge-Pond-General-Coarse-Fishery-Cyprypro.php

 

The weights are an exaggeration (it is an advertisement after all) in summer its very easy to blank on a bright day the place switches off from 10am to 3pm,nice place to night fish though very quiet indeed you could think it was only you on the planet and some days its only you on the pond! Come autumn your guaranteed to be the only one on the pond LOL

Edited August 23, 2016 by chesters1

[ayjay]

Get bitten often enough by flying insects later in the day, and usual suspects are around durng the daytime.

 

 

Doesn't this contradict your first post where you said it was devoid of smaller aquatic life?

 

Some of those little biters must surely have started life in water nearby.

[Steve Walker]

What's the water clarity like? Is there much submerged vegetation? What is the substrate like?

 

It's possible that most of the animal productivity is in zooplankton rather than in invertebrates living on the bottom.

[RUDD]

A few years back I posted about a big fish kill at a venue I adored.

Before the fish kill the lakes thrived with fish but apart from Lillie's and bankside plants there seemed to be hardly any insect or small aquatic life. Hardly bothered by insects when fishing.

 

The place has now made a recovery, over four tonnes of weed covered in life was removed a few months back, there are loads of fish which have been seen but not anywhere near the numbers before the kill. Catching them from that particular lake is hard work. Now loads of flying beasts of an evening causing annoyance as well.

I think before the fish kill an overstock of fish ate everything.

 

I also posted a bit about the deep clear water venue I fish.

Since the big carp all died (of old age, not SVC as many think) the smaller species have thrived,clouded up the water and seem to have killed off the zebra mussels?

There is not much aquatic life in this lake either.

I think the carp used to eat everything including spawn and fry.

Now the hundreds of small Perch and Roach eat everything.

 

To conclude, the fish in your lake eat anything before you get to see it.

20lb natural carp can hoover up plenty of natural food when in the mood!

[RUDD]

Oh forgot to mention, every natural or hardly fished venue I have fished including my two said above have been hard cookies to crack!

Un-fished for fish are ultra cautious of bait, I have found very small amounts of small baits (2mm pellets, pinkies, chopped worm, punched bread) to work best.

[philocalist]

What's the water clarity like? Is there much submerged vegetation? What is the substrate like?

 

It's possible that most of the animal productivity is in zooplankton rather than in invertebrates living on the bottom.

Water clarity varies very much according to whether or not prevailing winds are in action. If they are, surface movement appear to help agitate suspended solids and water clarity drops quite rapidly. Conversely, if wind stops, or hit the lake from a direction where the lake surface if relatively unaffected, then water clarity quickly improves again, though it's largely a bit academic, in the sense that much of the lake is around maybe 4 feet deep, with some areas dropping to maybe 6 feet - deepest bit we found was just over 7 feet and about the size of a table ... and was carefully marked as a potential holding area :-)

Apart from pygmy lilys coming up off the bottom onto the surface (giving blanket coverage where left unchecked), and well defined clusters of common pink / white lilys, there is little if any additional submerged vegetation of note, though there is good marginal growth over maybe 60% of the bank of a typical mix - bulrush, sedge etc mixed in with water mint and who knows what else?

Substrate? Lake was apparently lined upon construction (about 35 years ago), though obviously cannot vouch for integrity of the membrane after all this time ( though no obvious water loss). Bottom id substantially silt though not excessive - maybe 4 - 6 inches of the stuff, with other areas of dark clay, and some clean gravel around the margins of a central island.

We've not actually put water under a microscope, so cannot comment on zooplankton, but cutting / raking and removing lilys (including roots / corms / tubers produced nothing - an absolute ZERO - that could be seen with the naked eye. Net dipping, even with a very large fine net produced nothing but fry, i.e. no insects, beetles etc, and silt / mud off the bottom gives up nothing obvious either, even when observed against a large white try for contrast.

[Steve Walker]

It sounds to me as if all of the productivity is in the water column, and that there isn't a huge amount of it. The only plants growing are those that can get their roots into the sediment.

 

You can survey zooplankton with a net like this - just attach a long rope and drag it across the lake, or tow it behind a boat.

 

http://www.aquaticresearch.com/simple_plankton_nets.htm

 

I wouldn't go doing anything without testing the water over the course of the year (and lab tests rather than aquarium kit) and getting some professional advice, but it occurs to me that If it's isolated from groundwater and rain fed, it may be quite low in P and N. It's possible that fertilising the banks would help. Not a measure to be taken lightly though.

[philocalist]

Thanks for the input guys. In light of the communal head-scratching we're in the process of arranging a site visit from a specialist freshwater biologist, as a starting point.

I'll update this topic as and when, if anyone cares to know more about the outcome.

[Ken L]

Bet he recommends liming it....