Sammendrag
Rapporten oppsummerer anbefalingene fra fagråd for klassifisering
av ferskvannsfisk ble nedsatt for a gi forvaltningen rad om
egnede miljokvalitetsnormer (klassegrenser) for fisk som indikator
pa sentrale pavirkningsfaktorer i vassdrag. Vurderingene av
fiskebestandens tilstand anbefales gjennomfort ved hjelp av
et ”klassifiseringstre”, som er en strukturert dokumentasjon
av ekspertvurderinger av dagens tilstand i vannforekomsten
sammenlignet med en forventet referansetilstand. Dette er en
generell vurdering av tilstand uavhengig av pavirkningstype.
Vurderingene blir sikrere jo bedre datagrunnlaget er, men uansett
er det viktig at alle vurderinger dokumenteres og kvalitetssikres.
Referansetilstanden for fisk må i stor grad antas a vare lokalitetsspesifikk,
det vil si at fiskebestandens naturlige tilstand i stor grad
ma defineres for hver enkelt vannforekomst. Vi har imidlertid begynt
utvikling av mer typespesifikke referanseverdier for laksefisk i små
elver og bekker og pelagisk fisk i innsjoer.
The report summarizes work to develop methods for using data
on the fish stocks as an ecological quality element for classification
of water bodies (lakes and rivers) under EU’s Water Framework
Directive in Norway. The aim of the work in the “Advisory Committee
on Fish in the Water Directive” established by the Directorate for
Nature Management (presently the Norwegian Environment Agency)
in 2011was to:
Develop systems for characterizing the extent of impact by selected
human activities by recording certain parameters on fish populations.
Identify those parameters which may be applied in the definition of
ecological status class limits, and recommend how these parameters
should be treated.
Describe criteria to identify situations when the ecological status
of the fish populations is in in a less than Good status, i.e. when
mitigating actions are required concerning the water body, or
alternatively, the water body has to be classifies as Heavily Modified.
Fish is considered the most sensitive quality element in relation to:
1) hydromorphological changes (i.a., migration barriers and habitat
fragmentation), 2) acidification, and 3) introduction of alien species.
The reference condition for fish stocks in Norwegian lakes and rivers
must to a large extent be locality specific, due to the immigration
history of freshwater fishes and the topography of the country.
The assessment of the status of fish populations should be guided
by a system of expert judgement, which even when good data are
available, should be applied in the final classification of the water
body.
Water management, ecological status, freshwater fish, pressures, Vannforvaltning, økologisk tilstand, ferskvannsfisk, påvirkninger
av ferskvannsfisk ble nedsatt for a gi forvaltningen rad om
egnede miljokvalitetsnormer (klassegrenser) for fisk som indikator
pa sentrale pavirkningsfaktorer i vassdrag. Vurderingene av
fiskebestandens tilstand anbefales gjennomfort ved hjelp av
et ”klassifiseringstre”, som er en strukturert dokumentasjon
av ekspertvurderinger av dagens tilstand i vannforekomsten
sammenlignet med en forventet referansetilstand. Dette er en
generell vurdering av tilstand uavhengig av pavirkningstype.
Vurderingene blir sikrere jo bedre datagrunnlaget er, men uansett
er det viktig at alle vurderinger dokumenteres og kvalitetssikres.
Referansetilstanden for fisk må i stor grad antas a vare lokalitetsspesifikk,
det vil si at fiskebestandens naturlige tilstand i stor grad
ma defineres for hver enkelt vannforekomst. Vi har imidlertid begynt
utvikling av mer typespesifikke referanseverdier for laksefisk i små
elver og bekker og pelagisk fisk i innsjoer.
The report summarizes work to develop methods for using data
on the fish stocks as an ecological quality element for classification
of water bodies (lakes and rivers) under EU’s Water Framework
Directive in Norway. The aim of the work in the “Advisory Committee
on Fish in the Water Directive” established by the Directorate for
Nature Management (presently the Norwegian Environment Agency)
in 2011was to:
Develop systems for characterizing the extent of impact by selected
human activities by recording certain parameters on fish populations.
Identify those parameters which may be applied in the definition of
ecological status class limits, and recommend how these parameters
should be treated.
Describe criteria to identify situations when the ecological status
of the fish populations is in in a less than Good status, i.e. when
mitigating actions are required concerning the water body, or
alternatively, the water body has to be classifies as Heavily Modified.
Fish is considered the most sensitive quality element in relation to:
1) hydromorphological changes (i.a., migration barriers and habitat
fragmentation), 2) acidification, and 3) introduction of alien species.
The reference condition for fish stocks in Norwegian lakes and rivers
must to a large extent be locality specific, due to the immigration
history of freshwater fishes and the topography of the country.
The assessment of the status of fish populations should be guided
by a system of expert judgement, which even when good data are
available, should be applied in the final classification of the water
body.
Water management, ecological status, freshwater fish, pressures, Vannforvaltning, økologisk tilstand, ferskvannsfisk, påvirkninger
