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Fishing nets - Handling equipment

Plankton nets

Usage:

• plankton and fish fry sampling of all species and sizes
• catching plankton for feeding fish fry of all species
• catching plankton from shore and boat

Types of plankton nets

• Plankton dip net – net is attached to a metal frame equipped with a handle
• Plankton cast net – net is attached to a metal frame and supplemented by a string bin
• Plankton tow net – net is attached to large metal frame and usually towed by a boat
• Plankton static net – without frame to support, this net is attached to outflow tubes from ponds
• Static drift net – net is attached to a frame and installed into the current
• Apstein plankton net – net is attached to a cone-shaped metal frame by tightening
  - used for vertical sampling of plankton
• Closable Apstein plankton net – similar to a cast net
  - used for plankton sampling at chosen depths

Composition:

• fabric made from PA or PES threads
• precise mesh size
• mesh size 0.01, 0.02, 0.04, 0.1, 0.14, 0.2, 0.24, 0.34, 0.5, 0.6, 2 mm
• the mesh threads are fixed tightly to prevent displacement
• the upper edge of the net is made from firm PA or PES fabric to avoid damage
• possible to attach the net to a frame, depending on its usage
• the net can be attached to a frame and reinforced with additional strands when necessary
• the nets do not decay
• disinfectants do not harm the materials used

All nets in this section are made from the following materials:

• UHELON®
• NITEX®
• TYL®

products marked by this sign are also suitable for scientific research

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Plankton dip net

Usage:

• sampling plankton
• catching plankton for feeding purposes
• catching plankton near the water surface
• catching plankton from shore or boat

Design:

• net is attached to a circular frame with a handle
• possible to use nets of various mesh sizes

U-shaped net

• the same width in upper and lower part
• The advantage of this shape is high efficiency
  - larger sampling surface of the net
  - small escape of the plankton – net does not “wash itself out”
• the disadvantage is that it is difficult to empty the net

V-shaped net

• the net narrows towards the bottom – the bottom width is 10 cm
  - the bottom has half-circle shape
• the advantage is that the shape of the net easily facilitates emptying
  - the catch at the bottom of the net is reversed into a prepared container
• The disadvantage is lower catching efficiency

Sizes:

Materials used for plankton sampling

• circular frame diameter 20 cm
• wire diameter 6 mm
• metallized coating (electroplating)
• the height of protective hem 5 cm
• the net depth 30 cm
• V-shaped net
• the length of handle 150 or 180 cm

Plankton net used for large mass plankton catch for feeding

• circular frame diameter 40 cm
• wire diameter 8 mm
• metallized coating (electroplating)
• the height of protective hem 5 cm
• the net depth 70 cm
• V- or U-shaped net
• The length of the handle 150 or 180 cm

Frame diameter in cm	Wire diameter in mm	Mesh size in mm	The net depth in cm
20	6	0.01, 0.02, 0.04, 0.1, 0.14, 0.2, 0.24, 0.34	30
40	8	0.01, 0.02, 0.04, 0.1, 0.14, 0.2, 0.24, 0.34	70

We can attach new nets onto old frames made by our company.

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Plankton cast net

Essential tool for plankton sampling

Usage:

• catching all plankton species and sizes
• sampling in vertical and horizontal direction of water column
• sampling from shore or boat

Design:

• circular frame made from steel wire
• circular frame is supplemented with 3 binding spots
• possible to attach nets of various mesh sizes to the frame
• plankton cast net is supplemented by a string bin with diameter 3 mm
• net has an outlet tap
• tap serves as a weight for casting the net or lowering down the net
• possible to equip the net with additional weight for vertical sampling

Sizes:

• circular frame diameter 20, 30 and 40 cm
• wire diameter 6, 8 mm
• the net depth 40, 50, 60 cm
• mesh size – 0.04, 0.1, 0.14, 0.20, 0.24, 0.34 mm
• the protective hem height 10 cm
• 20 m string bin with string of diameter 3 mm
• net has an outlet tap

Frame DIAMETER / net depth in cm	Mesh size in mm	Protective hem height in cm	The string bin capacity in m
20/40; 30/50; 40/ 60	0.01, 0.02, 0.04, 0.1, 0.14, 0.2, 0.24, 0.34	5	30

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Cast net bag

Is an essential supplement for the plankton cast net

Usage:

• casing and protecting the plankton cast net
• comfortable carrying of the net in the field
• carrying sampling containers and catches

Design:

• cast net bag is made from breathable PA fabric, which dries fast
• beg is equipped with arm belt
• bag is equipped with inner pocket for samples, notes etc.

Sizes:

• 25 x 25 cm
• 35 x 35 cm
• 45 x 45 cm

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Plankton tow net

the net is usually towed by a boat

Usage:

• catching large plankton masses
• sampling of fish fry

Design:

• circular frame is made from steel wire
• circular frame is supplemented with 3 binding spots
• possible to attach various mesh sizes to a frame
• possible to divide the net in several mesh sizes to provide better water permeability
• larger mesh at the beginning and smaller at the end of the net
• net is made with outlet end
• possible to attach a collecting vessel at the end of net (it is not component of the net)

Sizes:

• circular frame diameter 90 cm
• wire diameter 8 mm
• mesh sizes: 0.04, 0.1, 0.14, 0.20, 0.24, 0.34, 0.5, 2 mm
• protective hem height 10 cm
• recommended depth 2 or 3 m
• 3 binding rings with tow harness of diameter 6 mm
• Outlet end – length 30 cm

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Plankton static net

• catching large plankton masses

Usage:

• installed into places with large current and large amount of plankton
• installed into outlet piping overflows etc.
• possible to draw water containing plankton into the net

Design:

• net has elongated cylindrical shape
• inlet has a firm protective hem
• draw tape is used for attaching net
• the inlet edge supplemented with tightening rings for net attachment
• the net has an outlet end

Instructions for use:

• net is installed into the water current, which carries plankton
• installation into outlet pipes, pumps, overflows etc.
• water flows through the net and plankton is caught
• mesh size determines the size of plankton caught
• it is recommended to have a net 2m or longer
• the advantages of a long net: will not clog; plankton stays alive and will not washed out

Sizes:

• net diameter 30 cm
• length 2, 3 or 4 m
• mesh sizes: 0.04, 0.1, 0.14, 0.20, 0.24, 0.34, 0.5 and 2 mm
• protective hem height 20 cm + tightening rings with diameter 8 mm
• protective hem height 20 cm + full hem with firm edge + draw metallic tape
• outlet end with length 40 cm

Diameter and length of the net is adjusted to the customer’s needs.

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Static drift net

Usage:

• sampling of benthic organisms in lotic waters
• sampling of drifting fish

Instructions for use:

• net is installed tilted against the water current
• disturbance of the bottom in front of the static drift net lift organism into the current
• drifting organisms are caught in the net
• the catch is removed from the outlet end

Net design:

• Net is usually rectangular in shape
• Inlet edge has a firm protective hem
• Dismountable frame is put into the hem
• The edge has tightening rings for attaching net to a frame
• Net has an outlet end

Frame design:

• dismountable frame is usually made from square tubes 20 x 20 mm
• frame has tightening rings or struts

Sizes:

• width 0.5 m, height 1 m
• mesh sizes: 0.34, 0.5, 2.0 mm
• protective hem height 10 cm
• depth usually 1.5 m
• outlet end 40 cm long

Diameter, length and size of the net are adjusted to the customer’s needs.

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Benthic dip net

Usage:

• sampling benthic organisms in lotic waters – streams and rivers
• sampling benthic organism living in muddy substrate of lentic waters – ponds, pools and lakes

Instructions for use:

• net is towed on the bottom and benthic organisms are sampled
• net is held perpendicularly to the bottom and disturbance of the bottom in front of benthic dip net lift the organism into the current
• net is burrowed into the soft bottom and organisms are sampled by horizontal haul

Sizes:

• mesh size 0.34, 0.4, 0.5, 0.6
• net width 30 cm, height 40 m, depth 60 cm + 5 cm helm
• protective bottom cover from PVC 30 x 45 cm
• the edge of the net has a firm protective hem made from PVC
• the bottom is protected against damage by bottom cover made from PVC
• frame is sewn into PVC protective hem
• the hem height is 5 cm

Frame

• wire diameter 10 cm
• frame width 30 cm, height 40 cm
• handle diameter 28 mm, length 1.5 or 1.8 m

Diameter, length and size of the net are adjusted to the customer’s needs.

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Apstein plankton net

• cone-shaped metal frame reduces turbulence in front of the net
• net surface is larger than the plankton cast net

Usage:

• used for plankton abundance assessment in water column
• used only for vertical sampling

RNDr. Jiří Macháček, CSc.

• senior scientist of Institute of Hydrobiology, BC AS CR, v.v.i., České Budějovice
• zooplankton research
• zooplankton sampling in the Rímov Reservoir
  machacek@hbu.cas.cz

Design of standard Apstein plankton net

• net is attached on a firm metal cone-shaped frame
• the entrance edge of the net has a doubled fabric hem
• the hem includes string to attach the net to the frame
• the outlet has an outlet tap
• combining nets into sets possible
• outlet tap serves as the weight for lowering the net
• providing tap with additional weight possible

Standard sizes:

• metal frame:
• upper diameter 20.5 cm
• lower diameter 39 cm
• height 40 cm
• net:
• net height 73 cm
• hem height 4.5 cm
• mesh size 0.04, 0.1, 0.14, 0.2, 0.24, 0.34, 0.5

MESH SIZES (in mm)	HEIGHT (in cm)	NET DIAMETER (in cm)	NET DEPTH (in cm)
0.04, 0.1, 0.14, 0.2, 0.24, 0.34, 0.5	113	39	73

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Usage of Apstein plankton net

Difference between standard and closable (Seda's modifi cation)

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Closable Apstein plankton net – new fi eld design (Seďa's modifi cation)

Advantages of closable Apstein plankton net

• easy to transport and store
• easy sampling manipulation
• sampling in targeted depth water column only
• closable sampling entrance in targeted depth able to close the mouth of the net at the targeted depth

Design

• the upper edge of the cone-shaped net has a circular frame with 3 binding rings
• cone-shaped inlet piece is made from fabric
• cone-shaped inlet can be closed at the targeted depth
• binding rings making net closable at the targeted depth are available at request
• this design is suitable for sampling several depth layers separately
• possible to keep the cone-shaped inlet open
• the net is made from polyamide - PA fabric of precise mesh size
• the outlet has an outlet tap
• outlet tap serves as the weight for lowering the net
• providing tap with additional weight for vertical sampling possible

Instructions for use:

• used for vertical sampling only
• net is lowered into targeted depth
• net is evenly pulled from depth
• the haul is performed with string attached to circular frame
• net includes 3 tightening rings to close net at targeted depth
• net is closed by pulling the colored string passed through rings
• the net is then hauled to the boat with colored string
• white strings stays loosened

WIRE THICKNESS (in mm)	CIRCULAR FRAME DIAMETER (in cm)	MESH SIZES	HEIGHT OF CONE-SHAPED EDGE (in mm)	NET DIAMETER (in cm)	NET DEPTH (in cm)	CLOSABLE
12	30	0.04, 0.1, 0.14, 0.2, 0.24, 0.34, 0.5	55	50	105	yes
12	40		55	70	105	yes
12	20		38	30	62	no
12	25		42	38	62	no
12	33		40	55	85	no

Profile

RNDr. Jaromír Seďa Ph.D.

• zoologist, ecologist, hydrobiologist; senior scientist of Institute of Hydrobiology, BC AS CR, v.v.i.
• zooplankton research specialist
• i am specialized in study of hybrids of gender Daphnia, their distribution and conditions determining their presence. These hybrids are distinguished only by biochemical tests. seda@hbu.cas.cz