Water quality - Guidelines for the selection of sampling methods and devices for benthic macroinvertebrates in fresh waters (ISO 10870:2012)

This International Standard describes the selection of sampling devices and methods (operation and performance characteristics) used to evaluate benthic macroinvertebrate populations in fresh waters (rivers, canals lakes and reservoirs). The devices and methods considered in this standard are suitable for sampling all major components of the benthic assemblage. They are not suitable for sampling mieofauna.

Wasserbeschaffenheit - Anleitung zur Auswahl von Probenahmeverfahren und -geräten für benthische Makro-Invertebraten in Binnengewässern (ISO 10870:2012)

Diese Internationale Norm beschreibt die Auswahl der Probenahmegeräte, die für die Beurteilung von benthischen Makroinvertebraten Populationen des Süßwassers (Flüsse, Kanäle, Seen und Talsperren) verwendet werden und deren Methodik (Einsatzbereiche und Funktionseigenschaften). Die in dieser Norm betrachteten Verfahren und Geräte sind geeignet für die Probenahme aller wesentlichen Komponenten der benthischen Besiedlung. Sie sind nicht geeignet für die Probenahme der Meio Fauna.

Qualité de l'eau - Lignes directrices pour la sélection des méthodes et des dispositifs d'échantillonnage des macro-invertébrés benthiques dans les eaux douces (ISO 10870:2012)

La présente Norme internationale spécifie les critères pour la sélection des méthodes et dispositifs d'échantillonnage
(fonctionnement et caractéristiques de performance) utilisés pour évaluer les populations de macro-invertébrés
benthiques dans les eaux douces (rivières, canaux, lacs et réservoirs). Les méthodes et dispositifs examinés
dans la présente Norme internationale conviennent à l'échantillonnage de l'ensemble des principaux composants
de l'assemblage benthique. Ils ne sont pas appropriés à l'échantillonnage de la méiofaune.

Kakovost vode - Navodila za izbiro metod in opreme za vzorčenje bentoških nevretenčarjev v celinskih vodah (ISO 10870:2012)

Ta mednarodni standard opisuje izbiro opreme in metod za vzorčenje (lastnosti in karakteristike delovanja), ki se uporabljajo za oceno populacij bentoških makronevretenčarjev v celinskih vodah (rekah, kanalih, jezerih in zbiralnikih). Oprema in metode iz tega standarda so primerne za vzorčenje vseh glavnih komponent bentoških združb. Niso primerne za vzorčenje meiofavne.

General Information

Status
Published
Public Enquiry End Date
19-Aug-2010
Publication Date
27-Dec-2012
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
06-Nov-2012
Due Date
11-Jan-2013
Completion Date
28-Dec-2012

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SLOVENSKI STANDARD
SIST EN ISO 10870:2013
01-januar-2013
1DGRPHãþD
SIST EN 27828:1997
SIST EN 28265:1998
SIST EN ISO 9391:1997
.DNRYRVWYRGH1DYRGLOD]DL]ELURPHWRGLQRSUHPH]DY]RUþHQMHEHQWRãNLK
QHYUHWHQþDUMHYYFHOLQVNLKYRGDK ,62

Water quality - Guidelines for the selection of sampling methods and devices for benthic

macroinvertebrates in fresh waters (ISO 10870:2012)

Wasserbeschaffenheit - Anleitung zur Auswahl von Probenahmeverfahren und -geräten

für benthische Makro-Invertebraten in Binnengewässern (ISO 10870:2012)

Qualité de l'eau - Lignes directrices pour la sélection des méthodes et des dispositifs

d'échantillonnage des macro-invertébrés benthiques dans les eaux douces (ISO
10870:2012)
Ta slovenski standard je istoveten z: EN ISO 10870:2012
ICS:
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.70 Preiskava bioloških lastnosti Examination of biological
vode properties of water
SIST EN ISO 10870:2013 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 10870:2013
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SIST EN ISO 10870:2013
EUROPEAN STANDARD
EN ISO 10870
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2012
ICS 13.060.70 Supersedes EN 27828:1994, EN 28265:1994, EN ISO
9391:1995
English Version
Water quality - Guidelines for the selection of sampling methods
and devices for benthic macroinvertebrates in fresh waters (ISO
10870:2012)

Qualité de l'eau - Lignes directrices pour la sélection des Wasserbeschaffenheit - Anleitung zur Auswahl von

méthodes et des dispositifs d'échantillonnage des macro- Probenahmeverfahren und -geräten für benthische Makro-

invertébrés benthiques dans les eaux douces (ISO Invertebraten in Binnengewässern (ISO 10870:2012)

10870:2012)
This European Standard was approved by CEN on 30 June 2012.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national

standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same

status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10870:2012: E

worldwide for CEN national Members.
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SIST EN ISO 10870:2013
EN ISO 10870:2012 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST EN ISO 10870:2013
EN ISO 10870:2012 (E)
Foreword

This document (EN ISO 10870:2012) has been prepared by Technical Committee ISO/TC 147 "Water quality"

in collaboration with Technical Committee CEN/TC 230 “Water analysis”, the secretariat of which is held by

DIN.

This European Standard shall be given the status of a national standard, either by publication of an identical

text or by endorsement, at the latest by January 2013, and conflicting national standards shall be withdrawn at

the latest by January 2013.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 27828:1994, EN 28265:1994, EN ISO 9391:1995.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech

Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,

Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,

Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

Endorsement notice

The text of ISO 10870:2012 has been approved by CEN as a EN ISO 10870:2012 without any modification.

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SIST EN ISO 10870:2013
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SIST EN ISO 10870:2013
INTERNATIONAL ISO
STANDARD 10870
First edition
2012-07-01
Water quality — Guidelines for the
selection of sampling methods and
devices for benthic macroinvertebrates
in fresh waters
Qualité de l’eau — Lignes directrices pour la sélection des méthodes
et des dispositifs d’échantillonnage des macro-invertébrés benthiques
dans les eaux douces
Reference number
ISO 10870:2012(E)
ISO 2012
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s

member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
Contents Page

Foreword ............................................................................................................................................................................iv

Introduction ........................................................................................................................................................................ v

1 Scope ...................................................................................................................................................................... 1

2 Terms and definitions ......................................................................................................................................... 1

3 Principle ................................................................................................................................................................. 2

3.1 General ................................................................................................................................................................... 2

3.2 Objectives .............................................................................................................................................................. 2

3.3 Sampling programmes ....................................................................................................................................... 3

3.4 Device and method selection ........................................................................................................................... 3

4 Benthic macroinvertebrates sampling methods and devices ................................................................. 3

4.1 General ................................................................................................................................................................... 3

4.2 Handnet .................................................................................................................................................................. 3

4.3 Surber sampler ..................................................................................................................................................... 7

4.4 Box sampler .......................................................................................................................................................... 9

4.5 Cylinder sampler ............................................................................................................................................... 11

4.6 Naturalist’s dredge ............................................................................................................................................12

4.7 Ekman-Birge grab .............................................................................................................................................14

4.8 Ponar grab ...........................................................................................................................................................15

4.9 Van Veen grab .....................................................................................................................................................16

4.10 Polyp grab (orange peel grab) .......................................................................................................................18

4.11 Air-lift sampler ....................................................................................................................................................19

4.12 Core and tube samplers ..................................................................................................................................22

4.13 Colonization samplers .....................................................................................................................................23

Bibliography .....................................................................................................................................................................26

© ISO 2012 – All rights reserved iii
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International

Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 10870 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 5,

Biological methods.

This first edition of ISO 10870 cancels and replaces ISO 7828:1985, ISO 8265:1988, and ISO 9391:1993, which

have been technically revised.
iv © ISO 2012 – All rights reserved
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
Introduction

Macroinvertebrates are an important component of fresh-water ecosystems and are the most widely used biological

group to monitor aquatic ecological status (Reference [6]). A wide range of sampling and survey methodologies

has been developed for a variety of specific applications as well as ecological assessment including: conservation

status, biodiversity assessment, pollution control, and habitat enhancement (Reference [7]).

This International Standard gives guidelines on the selection, design, operation, and performance characteristics

of sampling devices for the evaluation of benthic macroinvertebrate taxonomic composition, abundance, and

diversity in fresh waters, which can all be components of the applications given in the first parargraph.

© ISO 2012 – All rights reserved v
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SIST EN ISO 10870:2013
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SIST EN ISO 10870:2013
INTERNATIONAL STANDARD ISO 10870:2012(E)
Water quality — Guidelines for the selection of sampling methods
and devices for benthic macroinvertebrates in fresh waters

WARNING — Working in or around water is inherently dangerous. This International Standard does

not purport to address the safety problems associated with its use. It is the responsibility of the

user to establish appropriate health and safety practices and to ensure compliance with any national

regulatory conditions.
1 Scope

This International Standard specifies criteria for the selection of sampling methods and devices (operation and

performance characteristics) used to evaluate benthic macroinvertebrate populations in fresh waters (rivers,

canals, lakes, and reservoirs). The methods and devices considered in this International Standard are suitable

for sampling all major components of the benthic assemblage. They are not suitable for sampling meiofauna.

2 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
2.1
abundance

total number of individuals in a taxon, per sampling unit or estimated per unit area

2.2
benthic
dwelling at the bottom of an aquatic environment
2.3
canal

artificial watercourse constructed, usually, to join rivers, lakes or seas, and often of a size suitable for navigation

[2]
[SOURCE: ISO 6107-2:2006, 15]
2.4
deep water

water from 1 m below the water surface to the limiting depth for efficient sampling

2.5
diversity

species richness of a community and the distribution of individuals across those species

2.6
habitat

area of the environment in which a particular organism or population lives, including its characteristic

assemblages of plants and animals
2.7
lake
inland body of water of considerable area
[2]
[SOURCE: ISO 6107-2:2006, 57]
2.8
macroinvertebrate
invertebrate that is easily visible without magnification (>0,5 mm)
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
2.9
meio-fauna
small benthic invertebrates that pass unharmed through a 0,5 mm mesh
2.10
qualitative observation
observation that does not involve measurement or numbers
2.11
quantitative observation
observation that involves measurement or numbers
2.12
reservoir

construction, partially or wholly man-made, for storage and/or regulation and control of water

[2]
[SOURCE: ISO 6107-2:2006, 107]
2.13
river

natural body of water flowing continuously or intermittently along a well-defined course into an ocean, sea,

lake, inland depression, marsh or other watercourse
[2]
[SOURCE: ISO 6107-2:2006, 109]
2.14
semi-quantitative observation

observation on a sample where the relative abundance of taxa can be estimated, but not numerically related to

a specific area or volume of habitat
2.15
species/taxa composition

species/taxa list from the sampled habitat which can include the relative dominance (number of benthic

macroinvertebrates of a species/taxon divided by the total number of benthic macroinvertebrates of all

species/taxa, expressed as a percentage)
3 Principle
3.1 General

In order to evaluate benthic macroinvertebrate population parameters such as taxonomic composition,

abundance, and diversity in fresh waters, appropriate sampling devices are required. The choice of the

appropriate sampling device depends on the objective of the study itself as well as on the water type and the

benthic macroinvertebrate population being studied (Reference [6]).

Sampling methods are described in this International Standard to cover the broad variety of fresh waters and the

diversity of macroinvertebrate taxa and these habitats. The performance characteristics of the devices should

be taken into account in order to achieve the best evaluation in the context of the objectives of the survey.

3.2 Objectives

The methods given in this International Standard are suitable for a wide variety of objectives. These objectives

include: assessment of ecological status, detection of change in surveillance, operational and investigational

monitoring programmes, diagnosis of environmental stress, and the assessment of both acute and chronic

stressors (pollution control). The methods are also suitable for conservation and biodiversity assessments with

measurement of both community parameters and appraisal of rare species status. Many of the methods are

used both routinely and in research studies (References [6][11]–[14]). Guidance on the analysis of results from

[3] [4]
benthic macroinvertebrate surveys is given in ISO 8689-1 and ISO 8689-2.
2 © ISO 2012 – All rights reserved
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SIST EN ISO 10870:2013
ISO 10870:2012(E)
3.3 Sampling programmes

The design of a sampling programme depends on the aims of the survey and the required power of discrimination

of the data. The programme should be developed with regard to the local topographical and hydrological

conditions in the survey area, information on local environmental stressors, and knowledge from previous

surveys (if any). The number of sampling stations, their positions, season or seasons of sampling, and the

numbers of replicate samples to be taken at each station should be established prior to the initiation of the

survey, or through a pilot survey (Reference [6]). The design of the programme determines the options for data

treatment and statistical analyses that can be performed; therefore, prior consideration should be accorded

to the reporting requirements. Quality assurance of sampling and analysis should also be considered at this

[1]
stage. Further general guidance on survey design is given in ISO 5667-1.

During the design of the sampling programme, consideration should be given to the possibility of transferring

diseases (e.g. crayfish plague) and the dispersal of non-native invasive species. Appropriate precautionary

measures should be included in the operation of any of the devices to prevent such transfers.

3.4 Device and method selection

The methods and devices given in this International Standard have been chosen to achieve a good evaluation

for the broad variety of inland waters and the diversity of macroinvertebrate taxa. The methods and devices

are suitable for routine monitoring and for some research purposes. Methods and devices suitable only for

research purposes have been excluded. Detailed guidance on the design of sampling equipment, the mode of

operation and the scope of characteristics can be found in Clause 4. Three main selection criteria have been

evaluated in recommending suitable methods/devices for sampling different habitats. The three criteria are:

— suitability for operation in flowing or standing fresh waters;
— suitability for operation in shallow or deep fresh waters;

— the ability to provide results that are qualitative, quantitative or semi-quantitative.

Table 1 indicates which devices are appropriate for each habitat and in which section each device can be found.

4 Benthic macroinvertebrates sampling methods and devices
4.1 General

Benthic macroinvertebrates may be caught by active sampling or passive sampling (colonization samplers).

For all sampling methods, seasonal aspects of macroinvertebrate life cycles should be considered and taken

into account. The efficiency of active and passive sampling may also vary depending on the time (day/night)

of use; therefore the details of these aspects of use should be recorded. For those sampling devices that use

nets, it is important to consider mesh size in relation to the objectives of the survey. General comments about

mesh sizes applicable to all devices using nets are given in Table 2. The performance characteristics of each

sampling device can be found at the end of each section.
4.2 Handnet
4.2.1 General

No sampling technique is appropriate to all types of water and it is necessary to specify a number of sampling

procedures to meet different requirements. Sampling effort should be appropriate to the objectives of the study

and consideration of the physical characteristics of the site, and hence be based on suitable distance, area or

time (Reference [15]).

Sampling during and immediately after spates should be avoided (unless investigating the impacts of floods).

Samples collected at these times are not comparable with samples collected during periods of normal flow and

it is possible that they do not reflect the underlying environmental quality of the site accurately.

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SIST EN ISO 10870:2013
ISO 10870:2012(E)
Table 1 — Selection of devices for specific environments
Water Sample type
Equipment Clause
Still Flowing Deep Shallow Qualitative Semi-quantitative Quantitative
Handnet 4.2 P P P P P P —
Surber 4.3 — P — P P P P
Box 4.4 — P — P P P P
Cylinder 4.5 — P — P P P P
Naturalist’s
4.6 P P P — P P —
dredge
Eckman–Birge 4.7 P P P P P P P
Ponar grab 4.8 —
P P P P P P
Van Veen grab 4.9 P P P — P P P
Polyp grab 4.10 P P P — P P P
Air lift sampler 4.11 P P P — P P P
Core and tube
4.12 P P P — P P P
samplers
Colonization
4.13 P P P P P P —
samplers
P ≡ suitable — ≡ not suitable Maximum 4 m.
4.2.2 Frame design

A handnet consists of a handle and a frame, which holds a net in which organisms are collected. The handles are

usually made of metal, wood or reinforced plastic and the frames are usually constructed in metal. A rectangular

frame (see Figure 1) is preferred so the flat edge can be placed in close contact with the bed during use. The

vertical sides permit a larger cross-sectional area of water to enter the net than a triangular shape does.

The handnet frame should be large enough to allow a reasonable sample to be taken, but not so large that the

net offers too much resistance to the flow of water, which could make sampling difficult in fast flows. The length

of the net can be varied depending on the objective of the study. Suitable rectangular handnets currently in use

have evolved in the light of experience and have frame dimensions in the ranges listed in Table 2.

Table 2 — Handnet frame dimensions
Dimension mm
Width, b 200 to 400
Depth, d 400 to 500
Shoulder, d 100 to 200
Height, h 200 to 300
4.2.3 Net design

In choosing an appropriate net, two interrelated factors have to be considered; the dimensions and shape of

the net; and the mesh size of the net material. Finer mesh sizes increase the risk of clogging with organisms

and debris. This reduces net efficiency as it increases the tendency of water and organisms to flow around

the net rather than into it. This effect can be minimized by increasing the depth of the net (see Figure 1, depth

d), or by frequently emptying it. For guidance, Table 3 gives examples of the most suitable depths of nets as

a function of their size of openings. The shape of the net is not particularly important from a sampling point

of view but can be determined by practical considerations in manufacture. The net material is normally sewn

to strong canvas, which is attached to an inner frame. This material is more resistant to abrasion. Methods

of joining the inner and main frames, which facilitate replacement in the field, are clearly advantageous. Net

4 © ISO 2012 – All rights reserved
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SIST EN ISO 10870:2013
ISO 10870:2012(E)

material may be of a monofilament weave or knitted. However, monofilament is preferred due to its increased

strength. Synthetic fibre is preferable since it is stronger and less liable to decompose, but should be selected

to ensure sufficient flexibility. The mesh size should be appropriate for the objectives of the study. Increasing

the net mesh size decreases estimates of abundance and taxa richness. The maximum recommended mesh

opening sizes are given in Table 3.
Key
b width
d depth
d shoulder
h height
Figure 1 — A rectangular handnet
4.2.4 Handnet operation
4.2.4.1 General comments

When it is intended to collect as many taxa as possible, take a sample by a combination of the methods. It

is customary to explore thoroughly all the types of substratum by this method to assess ecological status,

including sweeps through weed patches and between the roots of overhanging trees.

Examine and wash the collecting net before and after samples are taken. Take care to ensure that the net is

not damaged or contaminated with animals from previous samples.
4.2.4.2 Kick sampling

The net should be held vertically on the riverbed downstream of the operator’s feet with the lower edge held

against the substrate. The substratum should be disturbed forcefully with the toe or heel of the boot and the

released material should be caught in the net. By working across the river, different habitats can be sampled.

This method is somewhat selective, because it is possible that fewer of the attached animals are taken than

unattached fauna, therefore some of the stones should be lifted and examined by hand where practical. To

allow semi-quantitative results to be calculated, the kick sample needs to be based on an agreed time or

an agreed area. Recommended times are between 2 min and 5 min to achieve a reasonable sample for

[5] [5]

routine ecological status assessment (EN 16150 ). EN 16150 gives guidance on replicate sampling with

© ISO 2012 – All rights reserved 5
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SIST EN ISO 10870:2013
ISO 10870:2012(E)

the handnet. Conservation and biodiversity studies designed to catch maximum numbers of taxa can require

longer sampling times.

The removal of the catch can be facilitated by using the flowing water to wash it into a corner of the net and

then shaking the net gently while removing it from the water. The net can then be turned inside out to aid the

transfer of the sample to a container of water. Animals which cling to the net can be removed by hand and then

added to the sample. It is recommended that the net be thoroughly washed between taking samples. Further

sample treatment, such as the decanting of surplus water (to minimize predation by carnivores), the reduction

of sample bulk by removing sticks, stones, leaves, and other debris as well as the addition of preservatives,

depend upon operator preference and the objective of the sampling programme. A sieve, of the same mesh

size as the net, can be used to reduce sample bulk.
Table 3 — Recommended handnet mesh sizes and nets depths
Maximum size of Recommended
Comments
mesh opening minimum depth
Survey objective
mm mm
General/routine
Danger that small stages of most
Biological monitoring: data for
0,5 to 1,0 400
benthos are not captured
surveys using biotic scores or
indices
For surveillance with more
Danger that early instar stages of many
complete records of taxa present, 0,5 450
insects are not captured
diversity indices
Ensures capture of first instar stages
For special surveys requiring
and very small organisms which
complete taxa lists including rare 0,25 550
may prove of value in water quality
taxa for conservation evaluation
determination
4.2.4.3 Sampling in very shallow flowing water by hand

Hold the lower edge of the handnet against the streambed while turning over the stones immediately upstream

by hand in the flowing water. Dislodged animals are carried into the net by the current. Examine the stones,

remove any attached or clinging species and add them to the sample. Disturb the finer lower deposits to

dislodge any further organisms.
4.2.4.4 Sampling in slow-flowing or still waters

In still water, it is possible that the handnet is not the most appropriate method for sampling because of the

requirement for flow to sweep the macroinvertebrates into the net. Consideration should be given to the use of

other methods and devices (Table 1). Some habitats, such as stony lake shores, can be sampled by the hand-

picking method, but this can cause collecting efficiency to be lower. The best procedure is to remove stones

carefully and agitate them vigorously in the net, after which any remaining animals can be picked off by hand

and added to the sample. When sampling other slow-flowing or still-water habitats, the absence or reduction of

water movement necessitates a different procedure from that used in flowing water where the current is used in

order to sweep dislodged animals into the net. In still water, it is necessary for the operator to supply the relative

motion of the fauna and net. The substratum should be disturbed with the feet and the dislodged fauna caug

...

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