Baltic Marine Environment Protection Commission
Continuation of the project on Baltic-wide assessment of
coastal fish communities in support of an ecosystem-based
management
FISH-PRO II 2-2015, 3-2
Copenhagen, Denmark, 10-12 February 2015
Document title
Code
Category
Agenda Item
Submission date
Submitted by
Updated draft Core indicator report “Abundance of coastal fish key functional groups“
3-2
CMNT
3 – Assessments and indicators
27.1.2015
Chair
Background
This document contains the draft updated Indicator Report “Abundance of coastal fish key functional
groups”. The indicator was re-named by HELCOM CORESET II 2-2014 to include “coastal” to clarify the scope
of the indicator.
The draft updated Indicator Report will be finilised as soon as possible and endorsed by the next Meeting of
the State and Conservation Group (STATE&CONSERVATION 2-2015) to be held during week 20 in May 2015.
Action required
The Meeting is invited to
 consider the general outline, content and message;
 consider specific questions raised by the Chair;
Contracting Parties are further invited to
 review the status of assessments of their respective monitoring areas.
FISH-PRO II 2-2015, 3-2
Abundance of coastal fish key functional groups
Key message
-
-
The status of functional groups of coastal fish in the Baltic Sea was derived by assessing the
status of piscivores and cyprinids.
For piscivores GES is achieved in half of the in total 36 monitoring areas assessed, and for
12 of in total 21 assessment units.
For cyprinids GES is only achieved in 11 out of in total 24 assessed areas, and for six of 16
assessment units.
As such, the environmental status for piscivores is better compared to that of cyprinids.
Generally the status of piscivores is better in more northern areas (Gulf of Bothnina)
compared to more southern and western areas. For cyprininds, the only region
characterized by GES is the Swedish coasts along the Bothnian Sea, Northern Baltic Porper
and Bornholm basin, as well as the coast in the Archipelago Sea.
The level of confidence of the assessment differs across areas, and is higher in those areas
having data dating back to the late 1990’s. Data is lacking for more southern and western
areas with respect to mesopredatory fish species, and in southern areas for piscivores.
Relevance of the core indicator
Coastal fish communities are of high socio-economic and ecological importance in the Baltic Sea, both for
ecosystem functioning in coastal areas and for the recreational and small-scale coastal commercial fishery.
FISH-PRO II 2-2015, 3-2
As such, the status of functional groups of coastal fish generally reflects the ecological state in coastal
ecosystems.
Changes in the long-term development of the abundance of functional groups coastal fish species mainly
reflect effects of increased water temperature and eutrophication in coastal areas and/or changes in the
level of anthropogenic exploitation or predation pressure.
Policy relevance of the core indicator
Primary importance
Secondary importance
BSAP
Segment and
Objective


MSFD
Descriptors and
Criteria
1.6. Habitat condition (condition of typical
species or communities, relative abundance
and/or biomass, physical, hydrological and
chemical conditions)

Natural Distribution and occurrence of
plants and animals
Thriving and balanced communities of
plants and animals
Healthy wild life
4.3 Abundance/distribution of key trophic groups and
species
Other relevant legislation: CFP?
Authors
The HELCOM FISH PRO II expert network on coastal fish: Jens Olsson (Department of Aquatic Resources,
Swedish University of Agricultural Sciences, Sweden). Lena Bergström (Department of Aquatic Resources,
Swedish University of Agricultural Sciences, Sweden). Antti Lappalainen (Finnish Game and Fisheries
Research Institute, Finland). Outi Heikinheimo (Finnish Game and Fisheries Research Institute, Finland). Kaj
Ådjers (Provincial Government of Åland Islands, Finland). Lauri Saks (Estonian Marine Institute, University
of Tartu, Estonia). Roland Svirgsden (Estonian Marine Institute, University of Tartu, Estonia). Eriks Kruze
and Laura Briekmane (BIOR Fish Resources Department, Latvia.) Linas Lozys (Nature Research Center,
Institute of Ecology, Vilnius, Lithuania). Adam Lejk (Marine Research Institute, Gdynia, Poland). Szymon
Smolinski (Marine Research Institute, Gdynia, Poland). Helmut Winkler (University of Rostock, Germany).
Norbert Schulz (Association Fish and Environment Mecklenburg-Vorpommern e.V., Germany). Josianne
Støttrup, (National Institute of Aquatic Resources, Technical University of Denmark, Denmark).
Cite this indicator
[Author’s name(s)], [2015]. [Indicator name]. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Indicator concept
Good Environmental Status
To assess Good Environmental Status (GES) for the abundance of coastal fish key functional groups in the
Baltic Sea, estimates of the relative abundance and/or biomass of coastal key functional groups as derived
from fishery independent monitoring, recreational fishermen surveys and/or commercial catch statistics
should be used. Since there are strong environmental gradients in the Baltic Sea and coastal fish communities
and stocks are typically local in their appearance and response to the area specific environmental conditions,
FISH-PRO II 2-2015, 3-2
the assessment for this indicator should be carried out on a rather local scale. Due to this small-scaled
variation in community structure, it is hence not applicable with Baltic wide reference levels and conditions
on which the boundaries for GES should be based. Coastal fish assessments should rather be based on area
specific boundaries for GES derived from time series data.
The quantitative boundaries for GES for coastal fish are either based on baseline conditions (time series
covering > 15 years) or on a trend based approach (time series covering > 15 years). The baseline period
should cover at least 10 years to extend over more than two times the generation time of the typically
species representing the indicator, to cater for natural variation in the indicator value due to for example
strong and weak year classes. For the baseline period to be comparable and relevant must be carefully
selected to reflect time periods with stable environmental conditions, as stated within the MSFD (Anon
2008). Substantial turnover in ecosystem structure in the Baltic Sea have been apparent in the late 1980s
leading to shifts in the baseline state (Möllmann et al 2009). For coastal fish communities, substantial shifts
in community structure have further been demonstrated in the late 1980s and early/mid 1990s (Olsson et
al 2012). In some areas, there have also been minor shifts in fish community structure also later
(http://helcom.fi/baltic-sea-trends/environment-fact-sheets/biodiversity/temporal-development-of-balticcoastal-fish-communities-and-key-species). The baseline period for coastal fish hence spans over a ten
years period beginning in the late 1990s. In the current assessment we have settled to include data from
1998 and onwards to cater for shifting baselines while including as much data as possible. The majority of
the available time-series of coastal fish community structure begin in the mid-1990s (HELCOM 2012). Using
the baseline-approach this suggest a baseline period of 1998 – 2008 and for the trend based approach data
should date back to the early/mid 2000s to be included in the assessment.
For the base line approach the assessment period should cover five years (2009-2013) to cater for natural
variability. GES is then assessed based on the deviation of the median value of the indicator during the
assessment period in relation to the variation of the indicator values during the base-line period. For the
trend-based approach, GES is assessed based on the direction of the trend of the indicator over the timeperiod considered in relation to the desired direction of the indicator.
The typical groups that the indicator is based on are piscivorous fish species and members of cyprinid
family or mesopredatory fish species, depending on the region of the Baltic Sea (see Table 1 for a
description on which species that are used in which area). Piscivorous fish coastal fish species are typically
represented by perch (Perca fluvialilis), pike (Esox Lucius), pikeperch (Zander lucioperca) and burbot (Lota
lota) at more in the less saline eastern and northern Baltic Sea (Sweden, Finland, Estonia, Latvia and
Lithuania), and in sheltered coastal areas in Poland and Germany. In the more exposed coastal parts of the
central Baltic Sea and in its western parts piscivores are typically represented by cod (Gadhus morhua) and
turbot (Psetta maxima). A similar division could be done for members of the cyprinid family (Cyprnidae, e.g.
roach and breams) that are most abundant in the less saline eastern and northern Baltic Sea, and
mesopredatory fish (sticklebacks, wrasses and gobies) that are representative for the more exposed coastal
parts of the central Baltic Sea and in its western more saline region.
FISH-PRO II 2-2015, 3-2
Anthropogenic pressures linked to the indicator
General
MSFD
Annex III,
Table 2
Strong connection
Several pressures, both natural and
anthropogenic, acting in concert affects the
status of key functional groups of coastal fish.
These include climate, eutrophication, fishing,
exploitation of essential habitats, food-web
interactions and predation from apex predators.
To date, no analyses on the ultimate importance
of all these variables have been conducted.
Secondary connection
Physical loss
- sealing
Physical damage
abrasion
selective extraction
Inference with hydrological processes
Significant changes in thermal regime
significant changes in salinity regime
Nutrient and organic matter enrichment
Inputs of fertilisers and other nitrogen —
and phosphorus-rich substances
Biological disturbance
selective extraction of species, including
incidental non-target catches
Potentially also:
Contamination by hazardous substances
Introduction of synthetic compounds
Introduction of non-synthetic
substances and compounds
There might also be effects of hazardous
substances on the status of coastal fish key
functional groups
The status of key functional groups of coastal fish in the Baltic Sea is influenced by a plethora of pressures
including climate, eutrophication, fishing, exploitation of essential habitats, food-web interactions and
predation from apex predators. The effects of a changing climate generally have a large impact on the
groups considered here (Möllman et al 2009; Olsson et al 2012; Östman et al submitted) as have
alternations in the food-web (Eriksson et al 2009; 2011), and the impact of increased water temperature
and lowered salinity is emphasized for cyprinids (Härmä et al 2011). Stressors related to anthropogenic
activities as foremost exploitation of essential habitats (Sundblad et al 2014; Sundblad & Bergström 2014)
impact both piscivores and cyprinids, whereas the effects of fishing is generally only valid for piscivores
(Edgren 2005; Bergström et al 2007; Fenberg et al 2012; Florin et al 2013). For obligate coastal piscivorous
species as perch. Pike and pikeperch, the outtake comes mainly from the recreational fisheries sector and
less from the small-scale commercial fishery (Karlsson et al 2014), whereas cod are mainly exploited in the
offshore commercial fishery. The role of eutrophication in mitagating effects on coastal fish communities
does not appear to be of as large importance (Olsson et al 2012), but the effect might increase with
increasing latitude (Östman et al submitted) and for some cyprinid species (Härmä et al 2011).
Another manageable pressuret hat at least locally might impact the status of coastal fish communities is
the predation pressure from apex predators, foremost cormorants (Vetemaa et al 2010; Östman et al
2012). Even if the outtake of coastal fish by cormorants generally exceeds that of the commercial fishery
and in some areas is comparable to that of the recreational fishery (Östman et al 2013), the magnitude of
the impact on coastal fish communities seems to vary between coastal areas (Lehikoinen et al. 2011). The
status of groups of mesopredatory fish species as wrasses, sticklebacks and gobies, and potentially also
cyprinids, could be affected by the food-web structure in coastal areas and neighboring ecosystems
(Eriksson et al 2011; Baden et al 2012; Casini et al 2012). Especially released predation pressure from
declining stocks of piscivorous fish species might favour the increase in abundance of mesopredatory fish
species.
FISH-PRO II 2-2015, 3-2
Relevance of the indicator
Policy Relevance
Coastal fish communities are of high socio-economic and ecological importance in the Baltic Sea. Coastal
fish, especially piscivorous species, is recognized as being important components of coastal food webs and
ecosystem functioning (reviewed in Eriksson et al., 2009, Olsson et al. 2012), and despite that many of the
species are not targeted by large-scale fisheries, they are important for the small-scale coastal fishery as
well as for recreational fishing (Karlsson et al 2014). The abundance of cyprinids and mesopredatory fish
might serve as good signals of the status of the ecosystem in that elevated abundances of both groups is
indicative of global warming, eutrophication and weak top-down regulation. Moreover, since many coastal
fish species are rather local in their appearance (Saulamo and Neuman, 2005; Laikre et al 2005; Olsson et al
2011), the temporal development of coastal fish communities might reflect the general environmental
state in the monitoring area. Coastal fish communities and stocks hence comprise important segments of
international policies and directives as the MSFD, BSAP, Habitats directive and Common Fisheries Policy.
Role of key functional groups of coastal fish in the ecosystem
Piscivorous fish species in coastal ecosystems have generally a structuring role in the system. Mainly via
top-down control on lower trophic levels, and viable populations of piscivorous species is generally
reflected by few eutrophication symptoms and balanced food-webs (Eriksson et al 2011).
The abundance of piscivorous coastal fish (such as perch, pike, pikeperch and cod) is influenced by the
recruitment success and mortality rates, which in turn might be influenced by ecosystem changes,
interactions within the coastal ecosystem and abiotic perturbations. An increased abundance of piscivorous
might reflect increasing water temperatures and moderate eutrophication (perch and pike), availability of
recruitment habitats (all), low fishing pressure and predation pressure from apex predators (all), but also
high eutrophication (pikeperch) as well as colder and more saline conditions (cod, Böhling et al., 1991;
Edgren 2005; Bergström et al 2007; Linlokken et al 2008; HELCOM, 2012; Olsson et al., 2012; Östman et al
2012; Bergström et al 2013; Östman et al submitted). As for the majority of coastal piscivorous fish species,
exploitation of recruitment areas has a negative impact on the development of perch populations
(Sundblad et al 2014; Sundblad & Bergström 2014).
Cyprinds and mesopredatory fish species typically represent lower trophic levels in being planktivores and
benthivores. As such these groups of species is both impacted by bottom-up mechanisms as eutrophication
(Härmä et al 2012; Östman et al submitted), but also by top-down regulation from piscivorous fish species
(Eriksson et al 2011; Baden et al 2012; Casini et al 2012) and apex predators (Östman et al 2012). Hence,
whereas abundant and strong populations of piscivorous coastal fish species is indicative for a functioning
ecosystem in good environmental status, high abundances of cyprinids and mesopredators are often
characterising systems in an undesirable environmental state.
Assessment protocol
Coastal fish datasets must meet certain criteria in order for an evaluation of GES using the baselineapproach to be applied:
1) The baseline data set should cover a minimum number of years, which should be two times the
generation time of the species most influential to the indicator evaluation in order to account for
the influence of strong year classes. For coastal fish, this is typically about ten years, yielding that
the base-line period should span over the years 1989-2008.
FISH-PRO II 2-2015, 3-2
2) The baseline data set must not display a linear trend within itself (n>10, p>0.05), as the baseline for
evaluation should optimally reflect the community structure at stable conditions and not a
development towards a change in the environmental status.
3) Before assessing GES, it should also be decided whether or not the baseline period reflects a period
of GES or not. This could be done either by using data dating back earlier then the start of the
baseline period, using additional information, or by expert judgment. If there, for example, is data
preceding the baseline period of much higher values than the one in the baseline period the
baseline might represent sub-GES (in case of an indicator where higher values is indicative of a
good environmental state) or GES (in case of an indicator where higher values is indicative of an
undesirable state).
Once coastal fish community structure at the baseline period has been defined, the GES-boundaries are
defined as the value of the indicator at the Xth percentile of the median distribution of the baseline data set.
The median distribution is computed by re-sampling (with replacement) from the baseline data set. In each
repetition, the number of samples equals the number of years in the baseline data set. In order to improve
precision, a smoothing parameter may be added in each repetition. The smoothing parameter is computed
as the normal standard deviation of the re-sampled data set divided by the number of years re-sampled. To
assess GES during the assessment period the median value of the indicators during the assessment period is
compared with the specific GES-boundary in that (see also decision tree below):
1) In situations where the baseline data set represents GES for piscivores, the median of the years to
be assessed (n=5) should be above the 5th percentile of the median distribution of the baseline data
set in order to reflect GES. For cyprinds and mesopredatory fish species, the median of the years to
be assessed (n=5) should be above the 5th percentile and below the 95th percentile to reflect GES.
2) In situations where the baseline data set represents sub-GES for piscivores, the median of the years
to be assessed (n=5) should be above the 98th percentile of the median distribution of the baseline
data set in order to reflect GES. For cyprinds and mesopredatory fish species the median of the years
to be assessed (n=5) should in order to reflect GES, be above the 98th percentile if the state during
the base-line period is indicative of too low abundances, and below the 5th percentile if the state
during the base-line period is indicative of too low abundances.
3) If the requirements for defining a quantitative baseline conditions are not met (e.g. short time-series,
or a linear development during the baseline period), trend based evaluation should be used. In this
case, GES is defined based on the direction of the trend compared to the desired direction of the
indicator over time. When the first years of the time-series assessed represents GES, the trend of the
indicator over time should not be negative in order to represent GES for piscivores. For cyprinds and
mesopredatory fish the trend of the indicator over time should not exhibited any direction to reflect
GES. If the first years of the time-series assessed represent sub-GES, the trend in the indicator should
be positive in order to represent GES for piscivores, and in the desired direction to reflect GES for
cyprinds and mesopredatory fish. The significance level for these trends should be p < 0.1.
Decision tree for GES evaluation using coastal fish community structure
In this tree the indicators abundance of key fish species is abbreviated as “key species”, abundance of
piscivores as “piscivores” and abundance of cyrpinids as “cyprinids”. Baseline refers to the period
1998/1999 – 2008. Mass period refers to the median of the assessment period (2009-2013), perc = percentile,
Mdistr baseline refers to the bootstrapped median distribution of the baseline period, and K is referred to as the
slope of the linear regression line over the whole time-period.
FISH-PRO II 2-2015, 3-2
Is there a baseline? Is there a trend in the baseline?
Trend based approach
Baseline approach
Baseline not avialable (data < 15 years), and/or trend during baseline
Baseline available (data > 15 years) and no trend during baseline
Higher values are be er (key
species, piscivores)
Baseline = GES
Values within boundary
desirable (cyprinids)
Baseline = subGES
Baseline = subGES
Too low values
Mass period > 5th
perc Mdistr baseline
Mass period > 98th
perc Mdistr baseline
Higher values are be er (key
species, piscivores)
Baseline = GES
Current state =
GES
Current state =
subGES
Kwhole period ≥ 0
Kwhole period > 0
Values within boundary
desirable (cyprinids)
Current state =
GES
Current state =
subGES
Too high values
Mass period < 5th
perc Mdistr baseline
Mass period > 5th
perc Mdistr baseline
and < 95th
perc Mdistr baseline
Kwhole period = 0
Kwhole period ≠ 0
and towards GES
(> 0 or < 0)
Status assessment of coastal fish communities should be assessed at a rather fine geographical scale due to
the local appearance of typical coastal fish species. In this assessment we have settled for the HELCOM
assessment unit level 3: “Open sub-basin and coastal waters”. The indicator is not assessed for the open
sea sub-basins since the species in focus are coastal in their appearance.
In assessment units harboring several monitoring areas the summed status was calculated as the status
(GES or subGES) representing the majority of areas within the unit. If equal numbers of had GES and
subGES, the one-out-all-out procedure was applied.
Results and confidence
The current evaluation of GES using coastal fish is based on time series data dating back to 1998-2002 using
a ‘deviation from baseline approach’ or a ‘trend-based assessment’ depending on the time-series coverage.
Evaluations were carried out on the assessment unit level 3 ’Open sub-basin and coastal waters’. The status
assessment per monitoring area and assessment unit is summarized in table 1. Only piscivores and
cyprinids was assessed here, due to a lack of data and fully developed indicators for mesopredators.
Piscivores
In half of the assessed areas (18 out of in total 36 areas) GES is achieved. In a few assessment units there
are departing environmental status across areas (Table 1), likely reflecting the local appearance of coastal
fish communities in the Baltic Sea. When summarizing over assessment units, GES is achieved in 12 out 21
assessed units, indicating an overall moderate environmental status of piscivorous coastal fish species in
the Baltic Sea. There are, however, some general patterns suggesting that the status depends on the
geographic area and species assessed. In more northern and eastern areas where perch, pike and pikeperch
are representing the coastal piscivores, the status is generally good (GES is achieved in 18 out of 23 areas),
whereas in more southern and western areas where cod and turbot are the dominating piscivorous species,
status is poor (GES is not achieved in any of the 13 areas assessed).
FISH-PRO II 2-2015, 3-2
In the northern most parts (Bothnian Bay and The Quark), the status is generally good (Table 1 and Figure
1). In most areas the relative abundance of perch, pike and perch is high and stable or increasing. Only in
one area, Norrbyn, the CPUE is decreasing over time.
In the Bothnian Sea, Åland Sea and Archipelago Sea, the relative abundances of piscivores is generally high
and stable, but not increasing (Figure 1). In the only area where GES is not achieved, Gaviksfjärden, there is
no temporal trend over the relatively short time-period covered, but the average abundance of piscivores is
more than half of that in the other areas monitored with the same gear (Långvindsfjärden, Lagnö, Finbo
and Kumlinge).
In the central part of the Baltic Sea (N Baltic Proper, Gulf of Finland, Gulf of Riga and Gotland Basin) there
are differences across areas in the status, and GES is only achieved in four out of seven assessment units
(Table 1). In the N Baltic Proper and Western part of the Gotland Basin GES is achieved, whereas in one of
the Gulf of Riga monitoring stations (Hiiumaa), the Swedish areas in the Gotland Basin (Kvädöfjärden and
Vinö), and in the Gulf of Finland all areas are characterized by subGES.
Except for Torhamn in Sweden (Bornholm basin), in the remaining assessment units and monitoring areas
mainly found in Danish waters where cod and turbot are the dominating piscivorous species, GES is not
achieved (Table 1).
FISH-PRO II 2-2015, 3-2
Table 1. Status assessment per monitoring area and assessment unit for piscivores. For the species column P = perch, Pi = Pike, B = Burbot……
Subbasin
Bothnian Bay
Bothnian Bay
Bothnian Bay
The Quark
The Quark
The Quark
Bothnian Sea
Bothnian Sea
Bothnian Sea
Bothnian Sea
Åland Sea
Archipelago Sea
Archipelago Sea
Archipelago Sea
Northern Baltic Proper
Gulf of Finland
Gulf of Riga
Gulf of Riga
Gotland basin
Gotland basin
Gotland basin
Gotland basin
Gotland basin
Bornholm basin
Arkona basin
Arkona basin
Belt sea
Belt sea
Belt sea
Belt sea
The sound
Kattegat
Kattegat
Kattegat
Kattegat
Kattegat
Country
Finland
Sweden
Sweden
Finland
Sweden
Sweden
Finland
Sweden
Sweden
Sweden
Sweden
Finland
Finland
Finland
Sweden
Finland
Estonia
Latvia
Sweden
Sweden
Latvia
Lithuania
Lithuania
Sweden
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Denmark
Monitoirng area
ICES SD 31
Råneå
Kinnbäcksfjärden
Rectangle 23 & 28
Holmön
Norrbyn
ICES SD 30
Gaviksfjärden
Långvindsfjärden
Forsmark
Lagnö
ICES SD 29
Finbo
Kumlinge
Askö
ICES SD 32
Hiiumaa
Daugagriva
Kvädöfjärden
Vinö
Jurkalne
Monciskes/Butinge
Curonian Lagoon
Torhamn
Præstø Fiord
Area south of Zealand (Smålandsfarvandet)
Sejerø Bay
Southern Little Belt and the archipelago
Århus Bay
Fiords of Eastern Jutland
The Sound
Isefjord and Roskilde Fjord
Northern Kattegat
Northern Limfjord
Hjarbæk Fjord
Venø Bay and Nissum Broad
Period
1998-2013
2002-2013
2004-2013
1998-2013
1998-2013
2002-2013
1998-2013
2004-2013
2002-2013
1998-2013
2002-2013
1998-2013
2002-2013
2003-2013
2005-2013
1998-2013
1998-2013
1998-2007
1998-2013
1998-2013
1999-2007
1998-2011
1998-2011
2002-2013
2005-2012
2008-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
2005-2013
Coastal water type
Species
Bothnian Bay Finnish Coastal waters
P, Pi, B
Bothnian Bay Swedish Coastal waters
Bothnian Bay Swedish Coastal waters
The Quark Finnish Coastal waters
The Quark Swedish Coastal waters
The Quark Swedish Coastal waters
Bothnian Sea Finnish Coastal waters
Bothnian Sea Swedish Coastal waters
Bothnian Sea Swedish Coastal waters
Bothnian Sea Swedish Coastal waters
Åland Sea Swedish Coastal waters
Archipelago Sea Coastal waters
Archipelago Sea Coastal waters
Archipelago Sea Coastal waters
Northern Baltic Proper Swedish Coastal waters
Gulf of Finland Finnish Coastal waters
Gulf of Riga Estonian Coastal waters
Gulf of Riga Latvian Coastal waters
Western Gotland Basin Swedish Coastal waters
Western Gotland Basin Swedish Coastal waters
Eastern Gotland Basin Latvian Coastal waters
Eastern Gotland Basin Lithuanian Coastal waters
Eastern Gotland Basin Lithuanian Coastal waters
Bornholm Basin Swedish Coastal waters
Arkona Basin Danish Coastal waters
Mecklenburg Bight Danish Coastal waters
Belts Danish Coastal waters
Belts Danish Coastal waters
Belts Danish Coastal waters
Belts Danish Coastal waters
The Sound Danish Coastal waters
Kattegat Danish Coastal waters, including Limfjorden
Kattegat Danish Coastal waters, including Limfjorden
Kattegat Danish Coastal waters, including Limfjorden
Kattegat Danish Coastal waters, including Limfjorden
Kattegat Danish Coastal waters, including Limfjorden
Assessment method
Baseline
Trend
Trend
Baseline
Baseline
Trend
Baseline
Trend
Trend
Baseline
Trend
Baseline
Trend
Trend
Trend
Baseline
Baseline
Trend
Baseline
Baseline
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Trend
Status
GES
GES
GES
GES
GES
subGES
GES
subGES
GES
GES
GES
GES
GES
GES
GES
subGES
subGES
GES
subGES
subGES
GES
GES
GES
GES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
subGES
FISH-PRO II 2-2015, 3-2
Bothnian Bay
Kinnbäcks ärden, Bothnian Bay, SE
Råneå, Bothnian Bay, SE
40
CPUE
CPUE
35
30
25
20
15
10
5
0
1998
2000
2002
2004
2006
2008
2010
20
18
16
14
12
10
8
6
4
2
0
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
1998
2012
ICES SD 31, Bothnian Bay, FI
0.4
CPUE
45
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
The Quark
Holmön, The Quark, SE
Norrbyn, The Quark, SE
180
160
0.45
0.4
25
CPUE
120
100
0.35
20
CPUE
140
CPUE
Rectangle 23, The Quark, FI
30
15
80
60
0.2
10
40
0.15
0.1
5
20
0
0.3
0.25
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Rectangle 28, The Quark, FI
0.4
0.35
CPUE
0.3
0.25
0.2
0.15
0.1
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
Bothnian Sea
35
120
12
30
10
CPUE
14
25
8
20
6
15
4
10
2
5
2000
2002
2004
2006
2008
2010
2012
ICES SD 30, Bothnian Sea, FI
0.6
0.5
0.4
0.3
0.2
0.1
0
1998
2000
2002
2004
2006
2008
2010
2012
2010
2012
Åland Sea
Lagnö, Åland Sea, SE
35
30
25
20
15
10
5
0
1998
2000
2002
2004
2006
2008
100
80
60
40
20
0
1998
CPUE
Forsmark, Bothnian Sea, SE
140
0
CPUE
Långvinds ärden, Bothnian Sea, SE
40
CPUE
CPUE
Gaviks ärden, Bothnian Sea, SE
16
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
FISH-PRO II 2-2015, 3-2
Archipelago Sea
ICES SD 29, Archipelago Sea, FI
Finbo, Archipelago Sea, FI
0.9
35
0.8
30
0.5
0.4
25
CPUE
CPUE
CPUE
0.7
0.6
Kumlinge, Archipelago Sea, FI
20
15
0.3
10
0.2
5
0.1
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
50
45
40
35
30
25
20
15
10
5
0
2012
1998
2000
2002
2004
2006
2008
2010
2012
Northern Baltic Proper
Askö, N Bal c Proper, SE
40
35
CPUE
30
25
20
15
10
5
0
1998
2000
2002
2004
2006
2008
2010
2012
Gulf of Finland
ICES SD 32, Gulf of Finland, FI
0.6
CPUE
0.5
0.4
0.3
0.2
0.1
0
1998
2000
2002
2004
2006
2008
2010
2012
Gulf of Riga
Daugagriva, Gulf of Riga, LAT
80
70
70
60
60
CPUE
CPUE
Hiiumaa, Gulf of Riga, EST
80
50
50
40
40
30
30
20
20
10
10
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Gotland Basin
Kvädö ärden, Gotland Basin, SE
Vinö, Gotland Basin, SE
60
Jurkalne, Gotland Basin, LAT
80
25
70
50
20
30
CPUE
CPUE
CPUE
60
40
50
10
30
20
20
10
5
10
0
0
1998
2000
2002
2004
2006
2008
2010
2012
70
160
60
140
CPUE
180
40
2000
2002
2004
2006
2008
2010
2012
Curonian Lagoon, Gotland Basin, LIT
80
50
0
1998
Monciskes/Bu nge, Gotland Basin, LIT
CPUE
15
40
120
100
80
30
60
20
40
10
20
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
FISH-PRO II 2-2015, 3-2
Bornholm Basin
Torhamn, Bornholm Basin, SE
60
CPUE
50
40
30
20
10
0
1998
2000
2002
2004
2006
2008
2010
2012
Arkona Basin
Area south of Zealand, Arkona Basin, DEN
Præstø Fiord, Arkona Basin, DEN
1.4
0.25
1.2
CPUE
CPUE
0.2
0.15
1
0.8
0.6
0.1
0.4
0.05
0.2
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Belt Sea
Sejerø Bay, Belt Sea, DEN
Southern Li le Belt and the archipelago, Belt Sea, DEN
1
3
2
0.8
CPUE
2.5
CPUE
CPUE
Århus Bay, Belt Sea, DEN
1.2
3.5
0.6
1.5
0.4
1
0.2
0.5
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
10
9
8
7
6
5
4
3
2
1
0
2012
1998
2000
2002
2004
2006
2008
2010
2012
Fiords of Eastern Jutland, Belt Sea, DEN
0.6
CPUE
0.5
0.4
0.3
0.2
0.1
0
1998
2000
2002
2004
2006
2008
2010
2012
The Sound
The Sound, The Sound, DEN
1.2
CPUE
1
0.8
0.6
0.4
0.2
0
1998
2000
2002
2004
2006
2008
2010
2012
Kattegat
Ise ord and Roskilde Fjord, Ka egat, DEN
Northern Ka egat, Ka egat, DEN
1.8
4
1.6
3.5
0.25
1
CPUE
3
1.2
CPUE
CPUE
1.4
Northern Lim ord, Ka egat, DEN
0.3
2.5
2
0.8
1.5
0.6
0.4
1
0.2
0.5
0
0.1
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
0.2
0.15
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
FISH-PRO II 2-2015, 3-2
Venø Bay and Nissum Broad, Ka egat, DEN
Hjarbæk Fjord, Ka egat, DEN
0.8
0.35
0.7
0.3
0.6
CPUE
CPUE
0.4
0.25
0.2
0.5
0.4
0.15
0.3
0.1
0.2
0.05
0.1
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Figure 1. Temporal development of piscivorous coastal fish species per subbasin in the different monitoring
areas assessed. A green line denotes GES in areas with a trend-based assessment, and a red line denotes
subGES. For some areas a baseline approach is applied. Here the red field represents subGES conditions,
the green field GES conditions, and the black line the median of the assessment period.
Cyprinids
The environmental status of cyprinids in the Baltic Sea is generally poor. In more than half of the assessed
areas (13 out of in total 24 areas) GES is not achieved, and only in ten out of 16 assessment units GES is
achieved. In the majority of the areas classified as subGES (nine out of 13), the abundance of cyprinids was
at too high levels, but in four Swedish areas (in the Bothnian Bay and Gotland basin), and in the only
Estonian area (Hiiumaa) the abundances appears to be too low. Since we lack monitoring and/or fully
developed indicators for mesopredatory fish, and assessment was only carried for cyprinids in the central
and northern parts of the Baltic Sea. Here it appears that subGES is characterizing almost the whole Finnish
coast except for the Archipelago Sea area, and large parts of the coastline of Latvia and Lithuania. Along the
Swedish coast GES is only achieved in the Bothnian Sea, Northern Baltic Proper and Bornholm basin.
In the northern most parts (Bothnian Bay and The Quark), the status is generally poor (Table 2 and Figure
2). In all but two Swedish areas (Råneå and Kinnbäcksfjärden), the abundance if cyprinids is too high to
achieve GES. In some of these areas, the abundance of cyprinids appears to increase over time.
In the Bothnian Sea, Åland Sea and Archipelago Sea, the relative abundances of cyprinids is generally stable
along the Swedish coast and Archipelago Sea (indicating GES), whereas along the Finnish Bothnian Sea
coast the abundance is too high (Figure 2).
In the central part of the Baltic Sea (N Baltic Proper, Gulf of Finland, Gulf of Riga and Gotland Basin) there is
an overall poor status of the assessed fish communities with respect to cyprinids. All but two of the in total
eight areas (Jurkalne, Latvia and Monciskes/Butinge, Lithuania) is characterized by subGES (Table 2). In the
southern most area assessed (Torhamn, Bornholm basin) the environmental status of cyprinids is good.
FISH-PRO II 2-2015, 3-2
Table 2. Status assessment per monitoring area and assessment unit for cyprinids.
Subbasin
Bothnian Bay
Bothnian Bay
Bothnian Bay
The Quark
The Quark
The Quark
Bothnian Sea
Bothnian Sea
Bothnian Sea
Bothnian Sea
Åland Sea
Archipelago Sea
Archipelago Sea
Archipelago Sea
Northern Baltic Proper
Gulf of Finland
Gulf of Riga
Gulf of Riga
Gotland basin
Gotland basin
Gotland basin
Gotland basin
Gotland basin
Bornholm basin
Country
Finland
Sweden
Sweden
Finland
Sweden
Sweden
Finland
Sweden
Sweden
Sweden
Sweden
Finland
Finland
Finland
Sweden
Finland
Estonia
Latvia
Sweden
Sweden
Latvia
Lithuania
Lithuania
Sweden
Monitoirng area
ICES SD 31
Råneå
Kinnbäcksfjärden
Rectangle 23 & 28
Holmön
Norrbyn
ICES SD 30
Gaviksfjärden
Långvindsfjärden
Forsmark
Lagnö
ICES SD 29
Finbo
Kumlinge
Askö
ICES SD 32
Hiiumaa
Daugagriva
Kvädöfjärden
Vinö
Jurkalne
Monciskes/Butinge
Curonian Lagoon
Torhamn
Period
1998-2013
2002-2013
2004-2013
1998-2013
1998-2013
2002-2013
1998-2013
2004-2013
2002-2013
1998-2013
2002-2013
1998-2013
2002-2013
2003-2013
2005-2013
1998-2013
1998-2013
1998-2007
1998-2013
1998-2013
1999-2007
1998-2011
1998-2011
2002-2013
Coastal water type
Bothnian Bay Finnish Coastal waters
Bothnian Bay Swedish Coastal waters
Bothnian Bay Swedish Coastal waters
The Quark Finnish Coastal waters
The Quark Swedish Coastal waters
The Quark Swedish Coastal waters
Bothnian Sea Finnish Coastal waters
Bothnian Sea Swedish Coastal waters
Bothnian Sea Swedish Coastal waters
Bothnian Sea Swedish Coastal waters
Åland Sea Swedish Coastal waters
Archipelago Sea Coastal waters
Archipelago Sea Coastal waters
Archipelago Sea Coastal waters
Northern Baltic Proper Swedish Coastal waters
Gulf of Finland Finnish Coastal waters
Gulf of Riga Estonian Coastal waters
Gulf of Riga Latvian Coastal waters
Western Gotland Basin Swedish Coastal waters
Western Gotland Basin Swedish Coastal waters
Eastern Gotland Basin Latvian Coastal waters
Eastern Gotland Basin Lithuanian Coastal waters
Eastern Gotland Basin Lithuanian Coastal waters
Bornholm Basin Swedish Coastal waters
Assessment method
Baseline
Trend
Trend
Baseline
Baseline
Trend
Baseline
Trend
Trend
Baseline
Trend
Baseline
Trend
Trend
Trend
Baseline
Baseline
Trend
Baseline
Baseline
Trend
Trend
Trend
Trend
Status
subGES
subGES
subGES
subGES
subGES
GES
subGES
GES
GES
GES
GES
subGES
GES
GES
GES
subGES
subGES
subGES
subGES
subGES
GES
GES
subGES
GES
Baltic Marine Environment Protection Commission
Continuation of the project on Baltic-wide assessment of
coastal fish communities in support of an ecosystem-based
management
FISH-PRO II 2-2015, 3-2
Copenhagen, Denmark, 10-12 February 2015
Bothnian Bay
Kinnbäcks ärden, Bothnian Bay, SE
Råneå, Bothnian Bay, SE
ICES SD 31, Bothnian Bay, FI
0.3
45
40
0.25
0.25
0.2
30
25
0.2
CPUE
CPUE
CPUE
35
0.15
0.15
20
15
0.1
10
0.05
0.1
0.05
5
0
0
1998
2000
2002
2004
2006
2008
2010
0
1998
2012
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
The Quark
Norrbyn, The Quark, SE
Rectangle 23, The Quark, FI
14
0.16
12
0.14
0.12
10
CPUE
CPUE
CPUE
Holmön, The Quark, SE
100
90
80
70
60
50
40
30
20
10
0
8
0.1
0.08
6
0.06
4
0.04
2
0.02
0
1998
2000
2002
2004
2006
2008
2010
2012
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Rectangle 28, The Quark, FI
0.25
CPUE
0.2
0.15
0.1
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
Bothnian Sea
Långvinds ärden, Bothnian Sea, SE
Forsmark, Bothnian Sea, SE
60
20
20
50
15
CPUE
25
CPUE
CPUE
Gaviks ärden, Bothnian Sea, SE
25
15
40
30
10
10
5
5
0
0
1998
2000
2002
2004
2006
2008
2010
2012
20
10
0
1998
2000
2002
2004
2006
2008
2010
2012
ICES SD 30, Bothnian Sea, FI
0.3
CPUE
0.25
0.2
0.15
0.1
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
2010
2012
Åland Sea
Lagnö, Åland Sea, SE
14
CPUE
12
10
8
6
4
2
0
1998
2000
2002
2004
2006
2008
Page 16 of 24
1998
2000
2002
2004
2006
2008
2010
2012
FISH-PRO II 2-2015, 3-2
Archipelago Sea
Finbo, Archipelago Sea, FI
0.2
20
0.15
Kumlinge, Archipelago Sea, FI
14
12
CPUE
25
CPUE
CPUE
ICES SD 29, Archipelago Sea, FI
0.25
15
0.1
10
0.05
5
0
0
10
8
6
4
1998
2000
2002
2004
2006
2008
2010
2012
2
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Northern Baltic Proper
Askö, N Bal c Proper, SE
45
40
CPUE
35
30
25
20
15
10
5
0
1998
2000
2002
2004
2006
2008
2010
2012
Gulf of Finland
ICES SD 32, Gulf of Finland, FI
0.45
0.4
CPUE
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
1998
2000
2002
2004
2006
2008
2010
2012
Gulf of Riga
Daugagriva, Gulf of Riga, LAT
120
30
100
25
CPUE
CPUE
Hiiumaa, Gulf of Riga, EST
35
20
80
60
15
40
10
20
5
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
2012
Gotland Basin
Kvädö ärden, Gotland Basin, SE
Vinö, Gotland Basin, SE
140
12
80
120
10
50
100
CPUE
60
CPUE
CPUE
70
80
8
6
40
60
30
4
40
20
2
20
10
0
0
1998
2000
2002
2004
2006
2008
2010
2012
400
40
350
35
300
CPUE
25
2000
2002
2004
2006
2008
2010
2012
Curonian Lagoon, Gotland Basin, LIT
45
30
0
1998
Monciskes/Bu nge, Gotland Basin, LIT
CPUE
Jurkalne, Gotland Basin, LAT
90
250
200
20
150
15
10
100
5
50
0
0
1998
2000
2002
2004
2006
2008
2010
2012
1998
2000
2002
2004
2006
2008
2010
Page 17 of 24
2012
1998
2000
2002
2004
2006
2008
2010
2012
FISH-PRO II 2-2015, 3-2
Bornholm Basin
Torhamn, Bornholm Basin, SE
30
CPUE
25
20
15
10
5
0
1998
2000
2002
2004
2006
2008
2010
2012
Confidence of indicator status
In the areas where monitoring started before 1999, the confidence of the evaluation is good, for the areas
with a shorter time-perspective the confidence is a bit lower. Also, coastal fish communities are typically
more local in their appearance than the scale of assessment applied here, and in some assessment areas
there are departing assessments across monitoring areas yielding a lower confidence of environmental
status. For especially the abundance of cyprinids data and assessments are limited to areas in the central
and northern parts of the Baltic Sea.
To improve confidence of the assessment longer time-series is obviously needed in some assessment areas,
and in some additional monitoring data. Data to support the development of indicators related to the
abundance and status of mesopredatory fish is also needed. Also work is needed on to further improve
confidence as well as on aggregation principles across areas and indicators.
Monitoring requirements
Monitoring methodology
Data source
Coastal fish monitoring using gill-nets is performed annually in all Baltic Sea countries, coordinated within
the HELCOM Fish PRO II expert network. The network includes data from fisheries independent monitoring
in Finland, Estonia, Latvia, Lithuania, Poland, Germany, Denmark and Sweden. Coastal fish communities in
the Baltic Sea areas of Russia are to some extent monitored as well. In Poland, a fishery independent
coastal fish monitoring program was established in 2014 (see Figure 2) and since no time-series data exist,
data from Poland was hence not included in the current assessment. In Germany, data are dervied from
coastal fish monitoring within national projects as the artificial reef program outside Rostock/
Warnemünde off the summer resort Nienhagen (since 2002), the eel monitoring progam along the
coastline of Mecklenburg-Western Pomerania (since 2008), and the coastal trawl survey in the Pomeranian
Bay by the University of Rostock (since 2003). None of these three projects have a long-term secured
funding. In Denmark, there is a coastal fish monitoring program without a long-term secured funding, via
the ”recreational fishermen survey” (initiated in 2005). Due to lack of geographical coverage, the status of
coastal fish communities in Finland are monitored using estimates of catch per unit effort from the smallscaled coastal commercial fishery. Additional areas are monitored than currently assessed (HELCOM 2015),
due to lack of national funding for carrying out status assessments (see figures below). This is especially
true for Estonia, Latvia and Lithuania.
Responsible institutes for sampling are Finnish Game and Fisheries Research Institute (Finland), Estonian
Marine Institute, University of Tartu (Estonia), BIOR Fish Resources Department (Latvia), Nature Research
Center, Institute of Ecology (Lithuania), National Marine Fisheries Research Institute (Poland), Association
Fish and Environment Mecklenburg-Vorpommern e.V. (Germany), University of Rostock (Germany),
National Institute of Aquatic Resources, Technical University of Denmark, Denmark (Denmark), Department
of Aquatic Resources, Swedish University of Agricultural Sciences (Sweden).
Page 18 of 24
FISH-PRO II 2-2015, 3-2
Description of data
Fishery independent monitoring
The calculations are based on catch per unit effort data (CPUE) from annual averages of all sampling
stations in each monitoring area. The coastal fish monitoring typically takes place in August and reflects
trends in species that occur in coastal areas during the warm season of the year. As such mainly demersal
and benthopelagic species with a temperature preference above 20˚C with a freshwater origin such as
perch, roach (Rutilus rutilus), breams (Abramis sp.), bleak (Alburnus alburnus) and ruffe (Gymnocephalus
cernuus) are targeted (Thoresson, 1996; Neuman, 1974). The sampling programs do to some extent also
catch marine species as cod (Gadus morhua), Baltic herring (Clupea harengus) and flounder, and those
species of a freshwater origin with lower a lower temperature preference such as whitefish (Coregonus
maraena) and smelt (Osmerus eperlanus).
In all countries except for Denmark fishing is performed using either survey nets, fyke nets or bottom trawl
or a combination of all three gear types, see HELCOM (2015) and Figure 2 for details. In Denmark, data on
coastal fish is collated by contracting recreational fishermen for catch registration (“Key-fishermen
project”). There is voluntary registration of all fish caught using commercial gillnets and fyke nets on fixed
monitoring stations monitored all year around (three times/month). The “Key-fishermen project” was
initiated in 2005, and is currently covering 18 areas along the Danish coast (Figure 3).
Commercial catch data
All commercial fishermen – including also “small-scale fishermen” using vessels under 10 meter long – are
nowadays obliged to report their fishing activities in EU countries on daily or monthly basis. The catch by
species and gear, as well as efforts and fishing areas as ICES statistical rectangles (55*55 km grids) are via a
log-book reported to national or regional fisheries administration. In the Finnish coast, for example, the
catch data has been collected in this form since 1980, and in 2010 over 1300 fishermen reported their
catches. Among the several gear-types used in the Finnish log-book for small scale fishery, the gillnet (36-60
mm bar length) is likely the most suitable to provide data for fish abundance indexes. Since Finland lacks
fisheries independent monitoring of coastal fish in many areas along the coastline, alternative data based
on commercial gillnet catches (36-60 mm bar length) was used for ICES statistical rectangles along the
Finnish coast. The data is effort-based in the form of kg/gillnet day.
Page 19 of 24
FISH-PRO II 2-2015, 3-2
Figure 3. Areas of fisheries independent monitoring for coastal fish in the Baltic Sea.
Geographical coverage
For the longest time-series (Net series and Coastal survey nets) data are available for Sweden, Finland,
Estonia, Latvia and Lithuania covering the Gulf of Bothnia and the northern and eastern parts of the Baltic
Proper (Figure 3). In Sweden, Finland and Estonia the coasts are extensive and rather heterogeneous, and
sampling programs only covers a part of the total stretch of coast. Particularly in the northern parts of
Finland (Gulf of Bothnia) and the southern parts of the Baltic Proper (Sweden), very little data from gill-net
monitoring is available. In Sweden, Finland and Poland, the spatial coverage is increasing when considering
the monitoring programs using Nordic coastal multi-mesh nets HELCOM (2012, 2015). These monitoring
programs were initiated in the early – mid 2000s and are as such too short to be included in this
assessment report. In Finland, effort based commercial catch statistics (CPUE) from the gillnet fishery are
available along the whole coastline, and might in some areas act as a complement to the gillnet monitoring
programs.
To summarize, the geographical coverage of the monitoring of coastal fish in the Baltic Sea covers the
northern parts rather well, but in some areas there are substantial gaps. Given that coastal fish
communities are typically local in their appearance and response to environmental and anthropogenic
Page 20 of 24
FISH-PRO II 2-2015, 3-2
perturbations (Saulamo and Neuman, 2002; Olsson et al., 2011, 2012a), additional monitoring programs
should be established and/or alternative data sources used in order to fully capture the current status of
coastal fish communities along all parts of the Baltic coast. With this in mind, however, a recent study
suggested that the temporal development of coastal fish communities in the Baltic during the last four
decades to some extent have followed a similar development across basins (Olsson et al., 2012b).
Moreover, during the last 15 years, where additional monitoring station can be considered, there has been
an overall similar development of coastal fish communities in the existing gillnet monitoring programs in
the Gulf of Bothnia (HELCOM, 2012). Coastal fish communities in gillnet monitoring programs in the Baltic
Proper has followed a different development trajectory compared to those in the Gulf of Bothnia, but
similar patterns are seen within the basin (HELCOM, 2012). In all, these studies together suggest that the
general and basin specific development trajectories of fish community structure in coastal gillnet
monitoring programs might be general also for areas currently not monitored, but that local and/or
regional exceptions might exist (HELCOM, 2012). Worth considering, however, is that the current
monitoring procedures of coastal fish in the Baltic Sea do not incorporate all features of the sampled
communities. Despite that the general development trajectories of coastal fish communities might overlap
between regions, the absolute abundances and production of the communities likely differs across areas.
As such, targets and levels for sustainable long-term management of coastal fish communities and the
levels for which reference states are defined for these , must be set within a relatively small geographical
scale, as for example within the HELCOM assessment unit 3 as used in this assessment.
Temporal coverage
The longest gillnet monitoring time-series included in this assessment covers the last 24 years and were
initiated in 1987. Many of the monitoring programs were, however, started later during the 1990s. Since
the late 1990s and early/mid 2000s data are available for the majority of areas, and the current assessment
hence cover this period in time. In Finland, effort based commercial catch statistics (CPUE) from the gillnet
fishery are available since 1980, but to enable comparisons of the assessments across areas, Finnish data
were only included from 1998.
Since financial support for monitoring and assessments in Latvia ceased in 2007, no further indicator
updates and status assessments can be undertaken. Also, in Lithuania monitoring is only undertaken every
third year, so no further update since 2011 is available. In Estonia, coatsla fish monitoirng is undertaken at
several locations (Figure 3), but funding is only aviablable for carrying out an assessment in one area
(Hiiumaa).
Methodology and frequency of data collection
Data are typically collected annually in August by national and regional monitoring programs. Commercial
catch statistics in Finland represent total annual catches.
See HELCOM (2015) for details. For future updates of this assessment, data should be collected on an
annual basis.
Methodology of data analyses
Fishery independent monitoring
The analyses were based on catch per unit effort data (CPUE) from annual averages of all sampling stations
in each area. To only include species and size-groups suited for quantitative sampling by the method,
individuals smaller than 12 cm (Nordic Coastal multimesh nets) or 14 cm (other net types), and all smallbodied species (gobies, sticklebacks, butterfish), and species with eel-like body forms (taeniform,
anguilliform or filiform shapes) were excluded from the analyses. Abundance was calculated as the number
of individuals of the key species per unit effort (CPUE).
Commercial catch data
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FISH-PRO II 2-2015, 3-2
Analyses were based on catch per unit effort data (CPUE) in the form of kg/gillnet day, and each data point
represents total annual catches per area. The gillnets used have mesh sizes between 36-60 mm (bar length)
and hence target a somewhat different aspect of the fish community in the area. In addition, fishing is not
performed at fixed stations and with a constant effort across years. As a result, the estimates from the
gillnet monitoring programs and commercial catch data is not directly comparable, and only relative
changes should be addressed across data sources.
Subregional specificities of the indicator
Due to the inherent difference in environmental settings of the Baltic Sea with pronounced gradients in for
example salinity and temperatures (Viopio 1981), the indicator might be based on different species groups
in different areas. In general, the piscivore indicator should be based on the abundance of perch, pike,
pikeperch and burbot in the northern parts and more in shore areas of the Baltic. In more exposed and
southern areas the abundance of cod and turbot and other piscivores should be included. Cyprinids
represent species from the carp family (Cyprinidae), and mesopredatory fish includes sticklebacks, wrasses
and gobies. Whereas Cyprinids are relevant for coastal areas the northern parts and more in shore areas of
the Baltic, mesopredators shoudl be assessed in more southern and western areas with higher salinities as
well as those areas that are more exposed to the offshore Baltic.
Description of optimal monitoring
The current coastal fish monitoring is covering the needs for assessments given the resources available. The
assessment would, however, have a higher confidence if all contracting parties ensured engagement of
national experts in updating and assessing status for the CORE indicators for all monitoring programs
running.
There are spatial and temporal gaps in the current monitoring. Due to the inherent environmental
gradients in the Baltic Sea (Voipio, 1981), and the rather local appearance of coastal fish communities in
their structure and response to environmental change, there are poor spatial and temporal coverage in
some areas (Figure 3). Therefore, assessments in some of these areas have to be based on alternative data
sources such as analyses of CPUE data from commercial fisheries, for which the use needs further
studiesFurthermore, the levels of direct anthropogenic impact in the existing monitoring areas are low, and
future venues should also assess the status in more impacted areas (Östman et al submitted).
It is crucial to stress that the current monitoring of coastal fish in the Baltic Sea represents a minimum level
of efforts, and serves as a very important first step for assessing the status of coastal fish communities. The
current monitoring is likely yielding insights into the major and large-scale changes in coastal fish
communities in the Baltic Sea, but unique responses in some areas could nevertheless be anticipated. For
future holistic assessments it is hence absolutely pivotal that the current extent of coastal fish monitoring
in the Baltic Sea is safe-guarded and fully financed. The monitoring in Latvia should, for example, receive
future financial support, monitoring in Lithuania and the other countries should be implemented on an
annual basis to meet minimum criteria for statistical consistency of the data, and long-term monitoring
should be secured in Poland, Germany and Denmark.
Moreover, the current monitoring is designed to target coastal fish species preferring higher water
temperatures and that dominates coastal areas in the warmer parts of the year, typically those with a
freshwater origin (see above). Monitoring of species like whitefish, herring and cod that dominates coastal
fish communities in the more exposed parts of the coast and during the colder parts of the year is,
however, rather poorly represented. In order to fulfil the requirements of international directives as the
Baltic Sea Action Plan and Marine Strategy Framework Directive, future monitoring of these species and
components should hence be established.
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Finally, in order to implement an ecosystem-based management and get a more holistic view of the
processes impacting Baltic Sea ecosystems, monitoring programs should ideally be coordinated in that
monitoring of as many trophic levels and abiotic variables (including contaminants, toxins and physiology)
as possible are performed in the very same region. For coastal fish, for example, information is
accumulating that apex predators as birds and seals might have substantial impacts on fish communities
and stocks in a severely disturbed ecosystem as the Baltic. At present, however, we have limited data on
the development and impact on coastal fish communities from foremost local cormorant and other
piscivorous bird populations. Moreover, there are data on seals, but we need additional information on
their diets and expected effects on Baltic fish communities. In addition to this, the catches of coastal fish
species are in many areas substantially higher in recreational fishing compared to that of the small-scale
commercial coastal fishery. Data on catches in recreational fishing is, however, typically poor in spatial and
temporal resolution, often also in the exact quantities. In order to fully understand the impact on coastal
fish community development as exerted by fisheries, data on catches from recreational fishing is needed. If
this kind of data could be effort-based, it might also serve as a compliment in estimating the abundance of
coastal fish species that are target species in recreational fishing and underrepresented in gill-net
monitoring programs.
Current monitoring
Coastal fish monitoring is rather wide-spread in the Baltic Sea (Figure 3), and does at present in some form
cover 33 of in total 42 assessment units for the HELCOM assessment unit level 3 (Figure 4). For a more
detailed description of the monitoring see above paragraphs and HELCOM (2015). The current assessment
will use data updated until 2013, but will only cover half of the assessment units (Figure 4) for piscivores,
due to either lack of monitoring and temporal coverage, lack of financial support to conduct the
assessments, lack of operational indicators to assess the status (typically on the west coast of Sweden, units
39 and 41). In three areas assessments will not be updated due to lack of national financial support (Latvia
and Lithuania). For Cyprinids a status assessment are only performed in 24 areas representing 16
assessment units (Table 2). Currently no assessment for mesopredatory fish is conducted due to lack of
data and indicators.
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Figure 4. Coverage of HELCOM assessment unit level 3 for current coastal fish monitoring (left) and status
assessment for piscivores (right).
Description of data and up-dating
Metadata
Some time-series of coastal fish begins in the 1970s (Olsson et al. 2012), whereas other was started in the
1980s (HELCOM 2012). The majority of the available time-series of coastal fish community structure was,
however, initiated in the mid 1990s (HELCOM 2012). In Finland and Sweden a new coastal fish monitoring
program with a higher spatial resolution was established in the early 2000s (HELCOM 2012).
No common data storage system currently exists for coastal fish, and data are stored in national data bases
and extracted for assessments. Different options for developing a regional database for coastal fish are
currently being investigated. The aim is to clarify options for data-arrangements for the purposes of the
core indicator during 2015.
No regionally common quality assurance routines exist for coastal fish. Quality is assured on a national
level.
Arrangements for up-dating the indicator
This core indicator on changes in abundance in the coastal fish community relies on national monitoring
data. Monitoring is carried out annually in most areas in order to accurately identify changes in the
community structure (but see above for exceptions).
The core indicator and future assessments is to be updated bi-annually based on the national data
coordinated via the HELCOM FISH-PRO II group that are lead by Sweden. Updating of the indicator and
assessments of its status could be carried out during the annual meetings of the HELCOM FISH-PRO II group
during early spring. Following this up-dated indicator reports could be uploaded to the HELCOM workspace
later that very spring. The up-dated indicator report will be reviewed by the upcoming HELCOM
State&Conservation meeting that very year after which the indicator will be published on-line.
Publications and archive
(Archive)

pdf:s of this and older versions of the indicator
Publications used in the indicator

can be references related to the concept/parameter etc.
MSFD (Anon 2008)
(Möllmann et al 2009)
(Olsson et al 2012)
(HELCOM 2012)
Additional relevant publications

can be general publications related to the parameter etc.
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