Spawning Rafts

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Just a quick question

What species are the spawning mats/boards aimed at?

Here's a useful link for habitat improvements in general. To start with.
http://www.therrc.co.uk/

Species such as Roach will spawn on Fontinalis moss on vertical pilings, Elodea beds, Willow roots, they prefer a flow of >20cm/s. Bream may spawn on stones in lakes but in rivers prefers areas with very little flow and a macrophyte substrate. Tench, Rudd and Carp lay eggs on submerged plants only and a great variety can be used.
Recruitment in any population depends on the suitability of spawning substrate. Most Cyprinids are known to migrate considerable distances during the spawning season and it is vital that any major obstacles do not hinder the migration.

It is also important to note that suitable habitat is available for the subsequent progeny of any spawning fish. For example Roach fry hatch after 12-12 days at 12.9 degrees C, are 4.6 - 6.5 mm long. For the first few days will remain attached to vegetation. The ideal habitat for fry is 1.5m depth with 0.5 - 1cm sandy/silt and gravel substrate. At 8-13mm shoaling occurrs, sensitivity to current decreases and a habitat of woody debris and vegetation is preferred.

Bream hatch at an average of 7-8 days at a temp of 18 degrees C, are 4-6mm. They have a gland on the head attched to vegetation. They are free swimming when yolk sac is absorbed. Heavy predation by invertebrates and fish up to this stage.

Improvements to Spawning Habitat

Natural materials like tree branches or bundles of willow fronds are ideal, man made inert items can also be utilised, polythen/plastic materials such as mesh, nylon fibrous mats and vegetable bags have all been used succesfully. These artificial substrates can be submerged or floating depending on the target species. Aquatic marshland vegetation that grows on artificial or natural floating material may provide spawning substrate. These surfaces are especially succesful when natural surfaces are absent. - Cyprinids.

Shallow bays planted with reeds can be constructed alongside existing channels, these act as a refuge in strong flows for fry as well as creating a spawning area. A floating spaning habitat can be formed by planks with floats and a plastic mesh floor covered with vegetation. Dimension 2m square.
Another alternative can be formed by dry vegetation or cut branches tied between light poles and mounted on the stream/pond/river bed - 2mx3m.
A bankside spawning habitat can also be formed by light pole and wire fence filled with vegetation and cut branches - 2mx3m.


I will post more info as i find it, hope this helps

Artificial Reefs and Overhangs

Reefs are suitable for enhancing lakes and slow areas that lack underwater features. They create sanctuaries of cover and shelter, spawning sites and areas of improved fish food production. Brushwood reefs can be made by tying bushes together and weighting them so they sink. Old tyres can also be used and are readily available, they will not contaminate the water. Each tyre will require several 2cm holes drilled in the upper tread to allow air to escape and sufficient bricks wedged on the lower side to sink it. It is suggested that artificial reefs occupy no more that 0.5% of the total area of the lake and that they be split into several seperate units. Their position must be clearly marked and accurately recorded so to avoid any conflicts, By attaching them together a variety of structures can be built, stacked multiple tyres forming pyramids or double units/triple units. Eventually macrophyte growth will provide lots of habitat for not only fish but invertebrates etc.

Artificial overhangs can be used to protect the banks of lakes and slow flowing rivers whilst producing additional cover for fish. They are designed to provide the same function as overhanging banks, hedges or bankside vegetation. The device consists of platforms constructed above the water surface and held in position by piles driven into the river bed, floating overhanging platforms are an alternative solution.

This is really related to Aquaculture of Carp but might give you some ideas...

There are a variety of substrates used in Carp farming, mats made up of fibres are used in asia, Half to one metre long fibres made of indjuk ( Arenga spp.) are arranged to form a 40 -70cm mat, pressed longitudinally between two bamboo lathes. They are placed on bamboo poles held in place between two pairs of shorter poles driven into the bottom. The mat remains slightly submerged but floats with the bamboo pole and adjusts itself to changes in water level. Native water weeds kept in place within a bamboo frame are also used. Israeli farmers use branches of Pine.
Artificial spawning mats made of synthetic material can be used. The mat area needed for a substrate is about 10m square for every 2-3 Kg of females. Spawning mats are easy to handle.

Don't know if this is of use but i am sure all these ideas can be modified to suit.

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what the hickety heck chris, do you know youre onions or what, nice one cass, lets hope the manager is ameniable, top posts fellas

have we any updates chaps, I know we have got the surrey butterfly club in there, concerning new habitat creation