Bsi bs en 14962 2006 (bs 6068 5 40 2006)

untitled BRITISH STANDARD BS EN 14962 2006 BS 6068 5 40 2006 Water quality — Guidance on the scope and selection of fish sampling methods The European Standard EN 14962 2006 has the status of a Britis[.]

BS 6068-5.40: 2006

Water quality —

Guidance on the scope

and selection of fish

sampling methods

The European Standard EN 14962:2006 has the status of a

British Standard

ICS 13.060.70

This British Standard was

published under the authority

of the Standards Policy and

A list of organizations represented on this subcommittee can be obtained on request to its secretary

Cross-references

The British Standards which implement international or European

publications referred to in this document may be found in the BSI Catalogue

under the section entitled “International Standards Correspondence Index”, or

by using the “Search” facility of the BSI Electronic Catalogue or of British

— aid enquirers to understand the text;

— present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed;

— monitor related international and European developments and promulgate them in the UK

Amendments issued since publication

Amd No Date Comments

EUROPÄISCHE NORM April 2006

ICS 13.060.70

English Version

Water quality - Guidance on the scope and selection of fish

sampling methods

Qualité de l'eau - Guide sur le domaine d'application et la

sélection des méthodes d'échantillonnage de poissons

Wasserbeschaffenheit - Anleitung zur Anwendung und Auswahl von Verfahren zur Probenahme von Fischen

This European Standard was approved by CEN on 16 March 2006.

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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G

Management Centre: rue de Stassart, 36 B-1050 Brussels

Contents Page

Foreword 3

Introduction 4

1 Scope 5

2 Normative references 5

3 Terms and definitions 5

4 Principle 6

5 Categories of rivers, lakes and transitional waters 6

6 Fish sampling 7

7 Selection of sampling methods 23

Bibliography 24

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom

IMPORTANT — It is absolutely essential that tests conducted according to this document be carried out by suitably trained staff

1 Scope

This document defines methods for sampling fish and procedures for selection of methods in order to evaluate fish populations in rivers, lakes and transitional waters A selected literature with references in support of this document is given in the bibliography This document refers to the standards “Water quality - Sampling of fish with electricity” (EN 14011) and “Water quality - Sampling of fish with multi-mesh gillnets” (EN 14757)

2 Normative references

Not applicable

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply

species list from the target water which may include the relative dominance (number of fish of species A in

relation to the total number of fish of all species [100 % ⋅ NA/NTot])

3.7

fish abundance

total number of fish of species A (NA) per water area (NA /m2, NA /ha), water volume (NA /m3) or river or bank

length (NA /m, NA /100 m); the catch per unit of effort (CPUE) as an index of abundance may also be used NOTE CPUE is the catch of fish, in numbers or in weight, taken by a definite unit of fishing effort The effort can be the number of nets set during the night, the length of a stretch sampled by electrofishing etc

3.8

age structure

number (N Ai ) or relative number (100 % ⋅ N Ai /NA) of fish of species A in age group i

NOTE Age groups may be derived by age determination of fish from e.g reading scales or from length-frequency data

4 Principle

In order to evaluate the population parameters, species composition, abundance and age structure of fish populations in rivers, lakes and transitional waters, appropriate sampling methods are required The appropriate sampling method depends on the objective itself as well as on the water type and category, the target fish species and their body length

Sampling methods are selected with respect to the broad variety of inland waters and to the diversity of species and their habitats The suitability of the given methods was classified in order to achieve a valid evaluation Their applicability for routine monitoring was taken into account

5 Categories of rivers, lakes and transitional waters

For the appropriate use of fish sampling methods rivers, lakes and transitional waters have been categorized The different water categories were selected for the purpose of this standard independent of other categories used in the terminology of limnological science or other standards

Categories for rivers and transitional waters are not defined directly by water velocity, although water velocity

is partly depending on river width and depth However, sampling methods should be chosen to be appropriate for the specific water velocity in the river (see also 6.4, Table 4)

The categories are as follows:

Table 1 — Categories for rivers

Category Width max Depth

River category 1 (brook) < 5 < 1 River category 2 > 5 < 2 River category 3 < 30 > 2 River category 4 30 to 100 > 2 River category 5 > 100 > 2

Table 2 — Categories for lakes

Category Presence or absence of a pelagic or profundal zone Area

Lake category 1 With or without a pelagic or profundal zone < 0,5

Lake category 2 Without a pelagic or profundal zone > 0,5

Lake category 3 With a pelagic and profundal zone > 0,5

Table 3 — Categories for transitional waters

Category Width max Depth

Transitional water category 1 < 5 < 1 Transitional water category 2 > 5 < 2 Transitional water category 3 < 30 > 2 Transitional water category 4 30 to 100 > 2 Transitional water category 5 > 100 > 2

Within a river or transitional water, categories according to the Tables 1 and 3 usually change from lower to higher ones according to longitudinal changes But also within a relatively short stretch of a river or transitional water, categories can change from lower to higher ones and vice versa In this case, the area itself of a river

or transitional water, and not the whole river or transitional water, should be classified according to the given categories

6 Fish sampling

6.1 General

Sampling methods are separated into methods by capture (6.2) and data sampling without fish capture (6.3) The principles are explained and the target water types or categories and fish species are given The suitability of the methods is evaluated depending on the different water categories and their habitats as well as the target species Target species are those species which can efficiently be caught by a particular method Tables 4 to 6 provide a synopsis on sampling methods suitable or useful for the determination of the population parameters

Methods not described below may be used in order to obtain additional information They shall not be used exclusively

6.2 Fish sampling by capture

6.2.1 Principle of fish capture

Fish may be caught by active gear (6.2.2 to 6.2.4) or passive (6.2.5 to 6.2.10) For all gear seasonal aspects shall be taken into account The efficiency of active gear (electric fishing, seining, trawling) especially may vary considerably depending on the time (day/night) of use Active gear is characterized by a comparatively short-term use, whereas passive ones normally are exposed over longer time periods The fishing devices used shall be adapted to the local conditions as well as to the expected fish community If it is intended to

determine the species composition and age structure, an adaptation of fishing gear mesh size(s), day time and season of exposure is required

In order to determine species composition and fish abundance of a certain water body the analysis of professional or non-professional fishery statistics1) may be considered as suitable, providing the statistics are based on binding regulations Whether such types of statistics can be used or not, depends on the reliability and exactness of the fishermen’s records In order to estimate fish abundance from fisheries statistics, information on fishing effort has to be included The age structure shall be determined by additional sampling Professional fishermen do not necessarily fish on all species occurring

Here species composition, fish abundance and age structure of the professionally unfished species shall be determined by additional sampling

6.2.2 Electrofishing

6.2.2.1 General

Electricity is led into the water by a special apparatus and fish are caught by the anodic effect (galvanotaxis) Catching fish with electricity is restricted to relatively shallow areas and to stretches of transitional waters with

a relatively low conductivity (γ < 6 mS/cm) Electrofishing can be carried out by wading or from a boat

Electric fishing is described in the standard “Sampling of fish with electricity” (EN 14011)

6.2.2.2 Electrofishing by wading

Principle: For electrofishing by wading a backpack, other portable device or a generator placed at the bank or

in a boat is used The member(s) of staff using one or more anodes wades/wade through the water and covers/cover all relevant fish habitats

Water types and categories: Electric fishing by wading can be carried out in rivers or transitional waters, categories 1 and 2 and in the littoral zone of larger rivers, transitional waters and lakes, where wading is possible without any risk

Target species: All fish species and sizes living in the areas can be caught

Suitability: Electrofishing is highly suitable for rivers categories 1 and 2, where the whole width of a river can

be covered by one or more anodes The efficiency can be increased by using stop nets at the beginning and

at the end of the target zone and by multiple fishing runs Due to the relatively high conductivity electric fishing

is only of medium suitability for transitional waters Under the conditions described above, samples for species composition, fish abundance and age structure can be collected

6.2.2.3 Electrofishing from a boat

Principle: A generator in combination with the required equipment is placed in a boat, sometimes also on the bank, and the member(s) of staff fish from the boat

Water types and categories: Electric fishing from a boat is possible in rivers where the max depth does not exceed 2 m and at the relatively shallow sides near the banks and shorelines of deeper rivers, lakes and transitional waters with γ < 6 mS/cm With adjusted electrofishing equipment the depth range may be extended up to a water depth of 3 m beside the banks or shorelines [27]

Target species: All fish species and sizes which stay in the areas described can be sampled

1) For the use of angling statistics see 6.2.10

Suitability: The efficiency is high in category 2 rivers It may be increased by using stop nets This method is also highly suitable for the littoral habitats of deeper rivers and lakes up to a maximum depth of 2 m Electric fishing in other regions of deeper waters may be useful only to obtain additional information on species composition Trammel nets set parallel to the bank of the target study stretch can be used to catch fish trying

to escape into deeper zones Generally, electric fishing cannot be carried out successfully in the middle of rivers or lakes, maybe with the exception of category 3 rivers Such fishing may be useful only to complete samples on species composition obtained by other methods

6.2.3 Seines

6.2.3.1 General

An area is surrounded with a net and pulled through The enclosed fish are forced to flee towards the end2) or a net bag from where they can be removed Several types of seines may be used for sampling fish in lakes, rivers or transitional waters

cod-6.2.3.2 Beach seine

Principle: Seining in the littoral, non vegetated zone using nets mostly < 50 m in length, < 3 m in height and mesh size preferably < 10 mm The whole water column from bottom to surface can be sampled The seine is pulled towards the bank by hand

Water types and categories: Generally, beach seines can be used in littoral habitats of deeper rivers or transitional waters cat 3 to 5 as well as lakes A beach seine may also be used in transitional waters categories 1 and 2 in order to complete samples obtained by electrofishing

Target species: Many species, especially their juveniles, are recorded

Suitability: Beach seines are especially useful in order to determine natural reproduction and in waters where electric fishing is difficult or impossible

6.2.3.3 Normal (bottom) seine

Principle: Seining in deeper areas using nets mostly > 50 m in length, > 3 m in height and mesh size > 10 mm

in the cod-end or the central panel The mesh sizes of the net walls of a seine are normally larger than those

in the cod-end The whole water column can be sampled The seine is pulled with ropes towards a bank, but can also be pulled into a boat Normal seines are moved by manpower or by engine power

Water types and categories: Normal seines can be used in lakes, rivers (cat 3 to 5) or transitional waters (cat

3 to 5) with a relatively even bottom without underwater obstacles The height of the seine shall be adapted to the depth of the target water or zone

Target species: The mesh size of the cod-end or the central panel of the seine affects the species and size distribution of the catch Therefore it may be difficult to catch juveniles and small species

Suitability: The length of a seine can be up to a few hundred meters, and accordingly a relatively large area can be surrounded Fish abundance or at least a CPUE can often be estimated Depending on the mesh size

of the cod-end only fish exceeding a certain size can be caught The samples on species composition and age structure from the respective area should be completed by samples collected with other methods

6.2.3.4 Pelagic seine (Purse seine)

Principle: Pelagic seines are mostly used in deeper lakes and samples are taken from the upper water layers Purse seines can be hundreds of metres in length and several metres in height

2) The cod-end is a long-stretched net bag at the end of a seine or a trawl

Water types and categories: Pelagic seines are useful in large and deeper lakes (category 3) Sometimes, pelagic seines may be used in small lakes (category 1) for special purposes

Target species: All species and stages which occur regularly in the pelagic habitat can be sampled

Suitability: Pelagic seines are highly suitable for estimating fish abundance or at least CPUE and the determination of species composition If the age structure shall be determined additionally, mesh sizes shall

be adapted or the pelagic seine shall be combined with other methods Pelagic seines are also suitable in combination with other methods where species identification is necessary

6.2.4 Trawls and push net

6.2.4.1 General

Trawling is carried out by pulling a funnel-shaped trawl net with either one or two boats (vessels) The size of

a trawl can vary from small experimental trawls to larger commercial trawls The speed during trawling affects catching efficiency Species composition and size distribution depend on the mesh size of the cod-end of the trawl

For special purposes, e.g the capture of larvae and juveniles, funnel-shaped nets are pushed beside or in front of a boat (push net)

6.2.4.2 Bottom trawl

Principle: Bottom trawls are pulled on the bottom by one or two vessels over a definite distance The riverbed

or the lake bottom should be relatively even In rivers with moderate or relatively high current, the trawl is pulled upstream, seldom downstream

Water types and categories: Appropriate water types and categories are rivers (cat 3 to 5), lakes (cat 2 to 3) and transitional waters (cat 3 to 5)

Target species: All fish species and sizes occurring in the habitat can be sampled

Suitability: Bottom trawls are highly suitable in larger rivers and transitional waters cat 4 to 5 as well as lakes (cat 2 to 3) where species composition, abundance and age structure can be determined In smaller rivers (cat 3) other sampling methods seem to be more efficient

6.2.4.4 Push net

Principle: Funnel-shaped nets are fixed beside or in front of a boat and pushed through the water

Water types and categories: Push nets may be used near the surface of lakes as well as rivers and transitional waters cat 4 to 5

Target species: Larvae and early juveniles are sampled by push nets

Suitability: Push nets are useful in order to sample near-surface water layers to obtain additional information

on the age structure

6.2.5 Gill nets and trammel net

pelagic multi-mesh gill nets is described in the standard “Sampling of fish with multi-mesh gillnets” (EN 14757)

Trammel nets are bottom nets which are used for special purposes or under certain circumstances

6.2.5.2 Bottom gill net

Principle: Bottom gill nets are set on the lake bottom or riverbed They may be fixed or anchored

Water types and categories: Bottom gill nets are mainly used in the lentic zone of rivers and transitional waters cat 3 to 5 and in all parts of lakes

Target species: Most of the species using the littoral or profundal zone can be sampled Species with eel-like morphology and some bottom dwelling species are regularly underrepresented, whereas some species may

be overrepresented due to morphological characteristics

Suitability: Bottom gill nets are highly suitable for the determination of species composition and age structure

as well as for estimating fish abundance In rivers and transitional waters, sampling with bottom gill nets may complete the samples on the population parameters gathered by other sampling methods

6.2.5.3 Pelagic gill net

Principle: Pelagic gill nets are floating on the surface or in a definite depth of the water column They may be anchored or not

Water types and categories: Pelagic gill nets can be used in deeper lakes in order to sample the pelagic habitat

Target species: All species and sizes living in the pelagic habitat can be sampled

Suitability: Gill nets with different mesh sizes are highly suitable for determining species composition and age structure and for estimating fish abundance

6.2.5.4 Vertical gill net

Principle: Vertical gill nets can sample the complete water depth (usually from 1 m to 80 m) The devices are

2 m wide and rolled tightly on PVC tubes which also act as floats They usually consist of multi-mesh sets and can be used as pelagic or bottom nets

Water types and categories: Vertical gill nets can be used in the pelagic or littoral parts of lakes and in rivers with low or no current

Target species: All species and sizes living in the pelagic or littoral habitat can be caught

Suitability: Vertical gill nets are highly suitable for determining species composition and age structure and for estimating fish abundance In rivers and transitional waters, sampling with vertical gill nets may complete the samples on the population parameters gathered by other sampling methods

6.2.5.5 Drift net

Principle: Gill nets drift and are carried along by the current

Water types and categories: Drift nets can be used in deeper areas in the middle of rivers or transitional waters, but also in shallow stretches where the nets can drift close to the bottom

Target species: Specimens which inhabit the upper water layers of larger rivers can be caught with drift nets Suitability: Drift nets can be used as an additional method to complete the samples for species composition and age structure in certain areas

6.2.5.6 Trammel net

Principle: Trammel nets consist of one small mesh sized net panel in the middle and two larger mesh sized

net panels outside

Water types and categories: Trammel nets may be used in littoral habitats of rivers or transitional waters with low current as well as in most parts of lakes

Target species: Most species can be sampled with trammel nets depending on the mesh sizes of the net walls Especially larger sizes are caught

Suitability: Trammel nets are useful for determining species composition and estimating abundance

6.2.6 Anchor nets

6.2.6.1 General

Anchor nets (gape nets, stow nets) are entrapment equipment which are set in larger rivers towards the current and anchored The mouth of the net is kept open by a frame, by two beams or by otter boards Migrating fish or those moving with the current are captured The mesh size of the cod-end affects the species composition and the size distribution

6.2.6.2 Anchor net fixed at a bank

Principle: One wing of the anchor net is fixed at a bank, while the other one is connected to an otter board which keeps the mouth open

Water types and categories: Anchor nets operated from a bank are useful in larger rivers or transitional waters cat 4 to 5

Target species: All species living in the habitat can be sampled, but especially migrating or moving species can be caught

Suitability: Anchor nets are highly suitable for larger rivers or transitional waters cat 4 to 5 The use of such anchor nets seems to be appropriate only when operated by professional fishermen

6.2.6.3 Anchor net used from a vessel

Principle: An anchor net (stow net) is operated from a vessel which is anchored in the river The mouth of the net is kept open by a frame or an upper and an under beam