Photo by Jürgen Reich

Population Development of Baltic Bird Species:
Great Cormorant (Phalacrocorax carbo sinensis)

 

	Authors: Christof Herrmann, Agency for Environment, Nature Conservation, and Geology of Mecklenburg-Western Pomerania, Germany Thomas Bregnballe, Danish Centre for Environment and Energy, Aarhus University, Denmark Kjell Larsson, Dept. of Biology, Gotland University, Visby, Sweden Ivar Ojaste, Environmental Board of Estonia Kalev Rattiste, Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences

 

Key message

During the 19^th century, the Great Cormorant was exterminated as a breeding bird in several Baltic countries. The persecution continued until the mid of the 20^th century, and in the early 1960s the European breeding population of the continental subspecies sinensis had declined to 4 000 breeding pairs (bp) only, of which Germany and Poland hosted more than the half. During the following two decades, the population development apparently has also been affected by the harmful effects of DDT and PCB.

As a result of protection measures, and seemingly also due to the ban of DDT and PCB, breeding pair numbers started to increase during the second half of the 1970s. During the 1980s, the Cormorant started to expand its range towards the northern and eastern parts of the Baltic. Currently, the species is present in the whole Baltic Sea area, including the northern parts of the Gulf of Bothnia.

After a decade of exponential growth, the breeding population of the Cormorant has stabilized in the south-western Baltic (Denmark and the northern Federal States of Germany - Schleswig-Holstein and Mecklenburg-Western Pomerania) in the 1990s, but breeding populations are still growing in the central and north-eastern parts of the Baltic Sea. However, the harsh winter 2009/2010 caused considerable declines in breeding numbers in the whole Baltic, including the north-eastern parts.

The highest population densities are found around the highly eutrophic estuaries of the southern Baltic (Odra-, Vistula-, and Curonian lagoon).

Results and assessments

Relevance of the indicator for describing developments in the environment

The Great Cormorant (Phalacrocorax carbo sinensis) is a representative of species which have been nearly extinct due to persecution in the 19^th and first half of the 20^th century. Its current development shows the recovery after the establishment of effective protection measures and the ban of DDT and PCB. The recovery takes place both in population size and in breeding range.

Furthermore, the Cormorant is a species which benefits from eutrophication.

Policy relevance and policy references

The Cormorant is protected by the provisions of the EU Bird Directive (79/409/EEC), which are implemented by the Member States into national law. This means, the legal protection status of the Cormorant is similar in all Baltic Sea states except of Russia. The species was deleted from the Annex I of the Bird Directive in 1997, i.e., there is no longer obligation for the Member States to establish Special Protected Areas (SPA). It is also not listed in Annex II of the Bird Directive, which means the national states are not allowed to give the Cormorant an open hunting season, i.e. the species cannot be a game bird. However, according to Article 9 (1) of the EU Bird Directive, under certain conditions the Member States may allow derogations from the protection provisions of the Directive. Since the Cormorant is considered to cause damages to fish stocks and fisheries, several Member States make use of Article 9 (1) and allow derogations with the aim “to prevent serious damage to crops, livestock, forests, fisheries and water”. The activities permitted by the responsible authorities include destruction of nests, oiling of eggs, and shooting. Furthermore, illegal actions against Cormorants are also reported from several countries.

Despite the possibility of derogations from the protection provisions, national as well as European fishery and angler associations strongly demand a management of the Cormorant population with the aim to reduce the population size. These demands resulted in a non-legislative resolution of the European Parliament, adopted on December 4, 2008, on “the application of a European cormorant management plan to minimise the increasing impact of cormorants on fish stocks, fishing and aquaculture.”

This resolution calls the Commission to “submit a cormorant population management plan in several stages, seeking to integrate cormorant populations into the environment as developed and cultivated by man in the long term without jeopardising the objectives of the Wild Birds Directive and Natura 2000 as regards fish species and marine and freshwater ecosystems. MEPs (Members of the European Parliament) urge the Commission, in the interests of greater legal certainty and uniform interpretation, to provide without delay a clear definition of the term ‘serious damage’ as used in Article 9(1)(a), third indent, of the Wild Birds Directive (The Wild Birds Directive (79/409/EEC) of 2 April 1979). The Commission should also produce more generalised guidance on the nature of the derogations allowed under Article 9 (1) of the Wild Birds Directive, including further clarification of the terminology where any ambiguity may exist.”

Furthermore, the MEPs suggest that, “by means of systematic monitoring of cormorant populations supported by the EU and the Member States, a reliable, generally recognised and annually updated database should be drawn up on the development, size and geographical distribution of cormorant populations in Europe. They call on the Commission to put out to tender, and finance, a scientific project aimed at supplying an estimation model for the size and structure of the total cormorant population on the basis of currently available data on breeding population, fertility and mortality. The Commission and the Member States are called upon to foster in an appropriate manner the creation of suitable conditions for bilateral and multilateral scientific and administrative exchanges, both within the EU and with third countries.”

(http://www.europarl.europa.eu/oeil/FindByProcnum.do?lang=en&procnum=INI/2008/2177).

In its response to the EP Resolution of 4 December 2008, the Commission recognises the need for co-ordinated action but does not consider that an EU-wide management plan would be an appropriate measure to address this problem. Under the Birds Directive there is no legally binding mechanism for an EU-wide management plan. Furthermore, there is no consensus between Member States on the type of action to take, or on the need and value of managing Cormorant populations at a pan-European scale. The Commission considers that it is not proportionate to argue for action at EU level to solve problems of a regional scale. Moreover, simply reducing the population will not necessarily reduce the numbers of Cormorants around the most attractive feeding sites or the impact on those fisheries and fish stocks. A combination of local control and mitigation measures has probably more chances of success than a general reduction of the population.

The Commission is also in favour of ensuring better scientific data and making available objective and updated information that could be widely accepted by all stakeholders regarding the populations and the biology of the Cormorants across the EU and their impact on fisheries. With this purpose in mind, the Commission establishes a platform for exchange and dissemination of technical information in particular on mitigation, non-lethal and lethal measures, social and economical issues and data on Cormorant populations. This will be an opportunity to bring together relevant experts, officials and stakeholders to identify the best way forward. It will be useful to promote regional cooperation among neighbouring countries concerned by this issue.

The following activities are currently undertaken by the Commission:

• The elaboration of a guidance document on Article 9 of the Birds Directive in relation to Cormorants, addressing issues such as “serious damage” as well as indicating what actions would be acceptable and compatible with the Directive, (draft, submitted to public discussion in September 2011);

• “Best Practice” solutions to reduce the impact of Cormorants on fisheries will be disseminated through the EU internet Cormorant Platform;

• A technical internet platform (the EU Cormorant Platform; http://ec.europa.eu/environment/nature/cormorants/home_en.htm), through which information of relevance for Member States and other users is made available, has been established; the Platform will be further developed during 2012 and 2013;

• Collaboration with the IUCN/Wetlands International Cormorant Research Group in order to organise pan European counts of breeding colonies (in 2012) and of night roost used in winter (January 2013).

Since the Baltic Sea area hosts a very large proportion of the European Cormorant population and since all Baltic Sea states except of Russia are Member States of the European Union, all activities and actions taken on EU level are directly relevant to HELCOM.

In February 2010, HELCOM HABITAT decided to establish an Expert Group on Cormorants under HELCOM HABITAT and stressed that the work of the group should focus on compiling Baltic-wide data and information and not on providing management recommendations (HELCOM HABITAT 2010).

Provisional conservation targets

Actions against the Cormorant with the aim to reduce damages caused to fisheries or impacts on threatened fish species as well as incidental killing in fishing gear should not affect the range and favourable conservation status of the species.

Assessment 

Cormorant Population Development in the Baltic Sea Area  

During the 19^th century, the Great Cormorant was exterminated as a breeding bird in several Baltic countries. Persecution continued during the 20^th century, though at a lower level. The European breeding population of the continental subspecies sinensis was small throughout the first half of the 20^th century. The species was successful in re-colonising Denmark in 1938 and Sweden in 1948 (Bregnballe & Gregersen 1995, Engström 2001). In the early 1960s, Germany and Poland hosted more than half of the entire European breeding population estimated at that time at c. 4 000 bp (Bregnballe 1996). During the 1960s until the mid-1970s the population was stagnant (Table 1), most likely due to harmful effects of DDT and PCB. Limited control measures may also have affected the population development at that time.

 

Table 1: Breeding pair numbers of the Cormorant in the Baltic Sea area 1959-1980.

 

	1959	1970	1975	1980
Denmark	333	250	940	2037
Sweden	100 [1]	175	337	753
Mecklenburg-Western Pomerania	900	1 035	856	705
Poland	1 800	1 100 [2]	1 300 [3]	1 400
Baltic Sea total	3 133	2 560	3 433	4 895

 

As a result of protection measures and presumably also due to the ban of DDT and PCB, breeding pair numbers began to increase during the second half of the 1970s (van Eerden & Gregersen 1994). By 1981, numbers in the Baltic Sea area had reached approximately 6 500 bp, and in 1991 the population was already about 51 000 bp. At the same time, an expansion to more eastern and northern breeding areas took place. In Estonia, the Cormorant started to breed in 1983, in Lithuania in 1985, on Gotland in 1992, and in Finland in 1996 (Žydelis et al. 2002, SYKE 2007, V. Lilleleht, pers. comm.). The range expansion even reached the northern part of the Bothnian Bay, where a colony was established in 2000. This northernmost Baltic colony of the Cormorant grew to 220 bp in 2008 (Lehikoinen 2006; SYKE 2008), but declined to 162 bp in 2011 (SYKE 2011).

In 2009, the total number of breeding pairs of Great Cormorants in the Baltic Sea riparian states was about 165 500 – 167 000 (Figure 1), which means only a slight increase compared to the numbers of 2006 (157 000 bp)^[4]. However, the harsh winter 2009/2010 caused an overall decline of the Baltic breeding population, which was as much as 21 % on the island Gotland, 20 % in Mecklenburg-Western Pomerania, 15 % in Denmark and 10 % in Finland (Figures 2-4). In 2011, a further decline was observed in the western Baltic, whereas in the central, eastern and northern Baltic remained about stable or increased slightly (Figures 2-4).

 

Figure 1:  Breeding pair numbers of the Great Cormorant in the Baltic Sea area 2006 and 2009. Data according to IUCN/Wetlands International Cormorant Research Group.

   

An annual complete Cormorant surveillance is established in some of the Baltic countries (e.g., Denmark, Germany, Estonia and Finland), but not in all (e.g., not in Sweden and Poland). However, the available data include representative samples from all parts of the Baltic Sea, giving a clear picture for the development in the different regions. In 2006, a pan-European Cormorant colony census has been performed (Wetlands International/Cormorant Research Group 2008). In 2012, this census will be repeated.

In the south-western part of the Baltic (Denmark, Schleswig-Holstein and Mecklenburg-Western Pomerania), the breeding pair numbers increased rapidly during the 1980s until the mid-1990s. From 1994-2008 the population has been fairly stable on a level of about 50 000 bp, but since then it has been strongly declining to c. 36 500 bp in 2011 (Figure 2).

 

 

Figure 2: Population development of the Cormorant in the south-western Baltic 1980-2011. 

 

The development on Gotland is an example of how numbers have developed in the central Baltic. The Cormorant began breeding at Gotland in 1992. The population has continued to increase until 2008, but decreased after 2008 (Figure 3).

 

  

Figure 3:  Number of breeding pairs of Cormorants on the island Gotland, Sweden. Data from K. Larsson, M. & B. Hjernqvist, and S. Hedgren.

 

The development in the eastern and northern parts of the Baltic is here illustrated using Estonia and Finland as examples. The first breeding of Cormorants in Estonia was recorded in 1983, but the population remained small (< 100 bp) until the end of the 1980s. At the beginning of the 1990s, breeding numbers started to increase rapidly. After 2003, the growth rate slowed down and the finally the population stabilized at a level of 13 600-13 700 bp in recent years. In Finland, the first breeding was recorded in 1996 and the population grew to about 16 000 bp in 2009, but decreased, as a consequence of the severe winter 2009/10, to 14 390 bp in 2010. In 2011, it grew again by almost one quarter (Figure 4; SYKE 2011)

 

 

Figure 4:   

Population development of the Cormorant in the eastern and northern Baltic (Estonia and Finland). Data from SYKE (2008, 2009, 2010, 2011), V. Lilleleht (2008), and K. Rattiste (2011, pers. com).

Regional distribution of breeding sites

The vast majority of the Cormorants breeding in the Baltic are nesting in colonies located near to the coast, and almost all large colonies >1 000 bp are found in coastal areas. The breeding sites are quite often islets where the birds build their nests on the ground or on trees.

The highest concentration of Cormorants is found around the highly eutrophic estuaries of the large rivers of the southern Baltic: Vistula Lagoon (11 500 bp in 2006 in a colony on Vistula Spit, Poland; Figure 5), Odra lagoon (10 750 bp in 2006 in five colonies in Mecklenburg-Western Pomerania and Poland), and Curonian Lagoon (11 300 bp in 2006 in two colonies on the Lithuanian and the Kaliningrad side of the lagoon). The largest colonies are: Katy Rybackie (at the Vistula Spit, Poland; 11 637 bp in 2006), a colony on the south coast of the Curonian lagoon (Kaliningrad region), and Peenemünde in the Odra lagoon area, Mecklenburg-Western Pomerania (4 861 bp in 2006).

 

 

Figure 5: The development of the largest European Cormorant colony on Vistula Spit, Poland, 1986-2009. Data from Przybysz (1997), Mellin et al. (1997), Goc et al. (2005), Goc (2006) and M. Goc & P. Stępniewski (pers. com).

 

Management actions for Cormorants

Some Baltic countries have initiated management actions to control breeding numbers in areas where Great Cormorants are causing conflicts with other interests such as fishery or protection of Salmon smolts (e.g. Bregnballe et al. 2003, Bregnballe & Eskildsen 2009, Engström 2001). These actions include oiling or pricking of eggs in ground nesting colonies (e.g. up to 18 % of all nests in Denmark and many nests in Sweden) and scaring of birds attempting to found new colonies in hitherto unexploited areas. Furthermore, many countries permit shooting of Cormorants according to the regulations of Article 9 (1) of the Bird Directive). Illegal actions against breeding Great Cormorants are also reported.

Cormorants have been shot since the early- or mid-1990s in Denmark (2 400-5 100 annually), Germany (1 500-2 500 in Mecklenburg-Western Pomerania and Schleswig-Holstein), and Sweden (2 000-8 000). In Estonia, shooting of Cormorants was started in 1997, but the bag remained low in all years, reaching a maximum of 707 in 2009. In Lithuania, in 2005 the Minister for the Environment issued a legal decree which forms the legal basis for licenses for shooting of Cormorants. In Finland, the government of Åland adopted guidelines for granting permissions to shot Cormorants in order to reduce damage to fisheries. However, most birds shot in Åland do not belong to the Baltic breeding population; they are migrants of the subspecies P. carbo carbo, which breeds in Norway and at the Russian coasts of the Arctic Ocean (SYKE 2010).

The total number of Cormorants shot in the Baltic Sea area is in the range of 10 000-20 000 birds annually and should not affect significantly the population development.

Illegal destruction of breeding sites is reported from several countries, e.g. Mecklenburg-Western Pomerania (2009), Estonia (2010), and Finland (2009, 2010, SYKE 2010).

 

Table 2: Shooting of Cormorants in Denmark, Sweden, the Baltic Federal States of Germany, Estonia and Lithuania.

Year	Denmark	Sweden	Mecklenburg-Western Pomerania	Schleswig- Holstein	Estonia[5]	Lithuania[6]	Finland[7]	Total
1993	1600		232	225	0
1994	2400		191	245	0
1995	3000		321	136	0
1996	3700		675	117	0
1997	4300		748	110	4
1998	3600		1142	626	0
1999	3700		363	677	41
2000	2400		603	681	42
2001	3700		829	610	102
2002	3400		1011	699	83
2003	3800	9028	1555	777	158			15318
2004	4900	5702	586	896	127			12211
2005	3700	3729	881	684	101	2596		11691
2006	4400	2157	688	1076	290	1782		10393
2007	5100	3504	1245	929	345	761		11884
2008	3900		1385	1244	407	484	96
2009	4300		1660	820	707		568

 

Besides shooting, incidental killing of Cormorants in fishing gear is another important anthropogenic mortality factor. Local studies and analyses of ring recovery data indicate that the number of birds drowned in fishing gear maybe high, at least in some regions (Bregnballe 1999, Bregnballe & Frederiksen 2006, I.L.N. & IfAÖ 2005; IfAÖ & I.L.N. 2006).

 

Metadata

Technical information 

Data sources: 

Population data 2006 have been obtained from the European Cormorant Count organized by the Wetlands International Cormorant Research Group and the "Extended network and conflict analysis project" of COST-INTERCAFE. During this census, counts were nationally coordinated by S. Bzoma, M. Goc, I. Mirowska-Ibron & M. Kalisiński (Poland), H. Engström & R. Staav (Sweden), A.R. Gaginskaya, V. Lilleleht, M. Dagys, G. Grishanov & I. Nigmatoulline (Russia, Estonia, Lithuania), and K. Millers (Latvia).

Population data 2009 have been obtained from published annual reports and presentations given at the Baltic Cormorant Symposium in Helsinki, 26-28 January, 2010; for Russia information given by G.V. Grishanov (KAL) and V. Fedorov (PET) has been included. For Poland, data of 2010 have been submitted by S. Bzoma; data for 2009 are not available.

Annual surveys of the breeding population are organized and data are collected by the following institutions or people^[8]:

Denmark: Danish Centre for Environment and Energy, Aarhus University (published on the web site: http://www.dmu.dk/dyrplanter/dyr/skarv_-_udvikling_i_bestande/)

Germany: Staatliche Vogelschutzwarte Schleswig-Holstein; Agency for Environment, Nature Conservation, and Geology of Mecklenburg-Western Pomerania.

Finland: Finnish Environment Institute (SYKE; published on the web site http://www.environment.fi);

Estonia: Vilju Lilleleht (until 2008), K. Rattiste & L. Saks (2009, 2010)

Gotland (Sweden): K. Larsson, M. & B. Hjernqvist, and S. Hedgren

Katy Rybackie (Poland): Michal Goc and Pawel Stępniewski

Lithuania: Annual counts in of the colony Juodkrante (largest Lithuanian colony) by the Curonian Spit National Park authorities; complete surveys of all Lithuanian colonies  complete survey of all Lithuanian colonies in 2005-2009 by the Institute of Ecology of the Nature Research Centre; complete survey 2011 is planned.

The numbers of Cormorants shot are available from national hunting reports. Hunting statistics are organized by national authorities in Germany, Denmark, Lithuania, and Estonia. Swedish data have been obtained from the Swedish Association for Hunting and Wildlife Management.

Geographical coverage: The data are covering the entire area of the Baltic Sea states.

The population developments shown in Figures 2-4 are representing annual nest counts in representative regions of the Baltic Sea (south-western Baltic: Denmark, Schleswig-Holstein, Mecklenburg-Western Pomerania; central Baltic: the island Gotland/Sweden, northern and eastern Baltic: Estonia and Finland.

Temporal coverage: see figures and table

Methodology and frequency of data collection: annual nest counts in all colonies in the sample areas (Denmark, Schleswig-Holstein, Mecklenburg-Western Pomerania, Gotland, Estonia, Finland); annual nest counts in the Katy Rybackie colony/Poland; Baltic-wide Cormorant count in 2006.

Quality of information

The reliability and quality of data is high.

 

References

Bregnballe, T. (1996): Udviklingen i bestanden af Mellemskarv i Nord- og Mellemeuropa 1960-1995 (English summary). Dansk Ornitologisk Forenings Tidsskrift 90: 15-20.

Bregnballe, T. (1999): Seasonal and geographical variation in net-entrapment of Danish Great Cormorants Phalacrocorax carbo sinensis. Dansk Ornitologisk Forenings Tidsskrift 93: 247-254.

Bregnballe, T., H. Engström, W. Knief, M.R. van Eerden, S. van Rijn & J. Eskildsen (2003): Development of the breeding population of great cormorants in The Netherlands, Germany, Denmark and Sweden during the 1990s. Die Vogelwelt 124: 15-26.

Bregnballe, T. & J. Eskildsen (2008): Danmarks ynglebestand af skarver i 2008. DMU Report, http://www.dmu.dk

Bregnballe, T. & J. Eskildsen (2009): Forvaltende indgreb i danske skarvkolonier i Danmark 1994-2008. – Omfang og effekter af oliering af æg, bortskræmning og beskydning. Danmarks Miljøundersøgelser, Aarhus University. Arbejdsrapport fra DMU nr. 249. http://www.dmu.dk/Pub/AR249.pdf

Bregnballe, T. & M. Frederiksen. (2006): Net-entrapment of great cormorants Phalacrocorax carbo sinensis in relation to individual age and population size. Wildlife Biology 12: 143-150.

Bregnballe, T. & J. Gregersen (1995): Udviklingen i ynglebestanden af Skarv Phalacrocorax carbo sinensis  i Danmark 1938-1994 (English summary). Dansk Ornitologisk Forenings Tidsskrift 89: 119-134.

Engström, H. (2001): The occurrence of the Great cormorant Phalacrocorax carbo in Sweden, with special emphasise on the recent population growth. Ornis Svecica 11: 155-170.

Goc, M.; L. Iliszko & L. Stempniewicz (2005): The largest European colony of the Great Cormorant on the Vistula Spit (N Poland) - an impact on the forest ecosystem. Ecol. Questions 6: 111-122.

Goc, M. (2006): Kormoran w Europie i Polsce: stan populacji, status prawny, regulacja liczebności. In: Wołos A., Niedoszytko B. (eds.) Jeziora Raduńskie: Przemiany i kierunki ochrony. Olszyn. Pages 73-85.

HELCOM HABITAT (2010): Minutes of the twelfth meeting of the Nature Protection and Biodiversity Group (HELCOM HABITAT); Tallin, 17-19 February 2010.

Herrmann, C. (2007): Bestandsentwicklung und Kormoranmanagement in Mecklenburg-Vorpommern. BfN-Skripten 204, 48-71.

IfAÖ & I.L.N. (2006): Räumliches und zeitliches Muster der Verluste von See- und Wasservögeln durch die Küstenfischerei in Mecklenburg-Vorpommen und Möglichkeiten zu deren Minderung. Research Report on behalf of the Agency for Environment, Nature Conservation, and Geology MV.

I.L.N. & IfAÖ 2005. Verluste von See- und Wasservögeln durch die Fischerei unter besonderer Berücksichtigung der international bedeutsamen Rast-, Mauser- und Überwinterungsgebiete in den Küstengewässern Mecklenburg-Vorpommerns. Research Report on behalf of the Agency for Environment, Nature Conservation, and Geology MV.

Koop, B. & J.J. Kieckbusch (2010): Kormoran. In: Jagd und Artenschutz 2010. Ministry for Agriculture, Environment and Rural Areas Schleswig-Holstein:113-115.

Lehikoinen, A. (2006): Cormorants in the Finnish archipelago. Ornis Fennica 83: 34-46.

Lilleleht, V. (2008): Kormorani levik ja arvukus 2007. http://keskkonnainfo.ee/failid/200807_kormorani_levik_arvukus_Eestis_2007.pdf

Männil, P. & R. Veeroja (2010): Status of Game populations in Estonia and proposal for hunting 2010. Estonian Environment Information Centre. http://www.keskkonnainfo.ee/failid/ULUKITE_SEIREARUANNE_2010.pdf

Mellin, M.; I. Mirowska-Ibron; J. Gromadzka & R. Krupa (1997): Recent development of the Cormorant breeding population in north-eastern Poland. Suppl. Ric. Biol. Selvaggina 26: 89-95.

Przybysz, J. (1997): Kormoran [Cormorant]. Lubuski Klub Przyrodników. Świebodzin. 108 pp.

Rattiste, K. & L. Saks (2010): Kormorani levik ja arvukus Eestis 2009. http://www.keskkonnainfo.ee/failid/Kormorani_levik_ja_arvukus%20Eestis.pdf

Staav, R. 2007. Storskarven i Sverige. In: SOF 2007. Fågelåret 2006. Stockholm.

SYKE (Finnish Environment Institute, 2007): Cormorant population grew by more than fifty percent from last year. Press release, 08/15/2007, http://www.environment.fi

SYKE (Finnish Environment Institute, 2008): Breeding population of cormorants now more than 10 000 pairs. Press release, 08/27/2008, http://www.environment.fi

SYKE (Finnish Environment Institute, 2009): Nesting cormorant population grew by one quarter since last year. Press release, 08/03/2009, http://www.environment.fi

SYKE (Finnish Environment Institute, 2010): Number of breeding Cormorants declined due to harsh winter conditions, 08/16/2010, http://www.environment.fi

SYKE (Finnish Environment Institute, 2011): Finland’s cormorant population grew by almost one quarter, 08/09/2011, http://www.environment.fi

Wetlands International/Cormorant Research Group (2008): Cormorants in the western Palearctic. Distribution and numbers on a wider European scale. Leaflet CRG count: http://ec.europa.eu/environment/nature/cormorants/files/Leaflet_CRG_Count_2003-2006.pdf

Žydelis, R., G. Gražulevičius, J. Zarankaitė, R. Mečionis & M. Mačiulis (2002): Expansion of the Cormorant (Phalacrocorax carbo sinensis) population in western Lithuania. Acta Zoologica Lituanica 12: 283-287.

Van Eerden, M. R. & J. Gregersen (1995): Long-term changes in the northwest European population of Cormorants Phalacrocorax carbo sinensis. Ardea 83: 61-79.

 

Footnotes 

[1] Numbers for 1957, for 1959 no data available.

[2] Numbers for 1972

[3] Numbers for 1973

[4] Numbers include inland colonies; for Germany, only to the Baltic Federal States Mecklenburg-Western Pomerania and Schleswig Holstein are considered, for Russia St Petersburg and Kaliningrad regions.

[5] Numbers 2002-2009 according to Männil & Veeroja (2010)

[6] Numbers shot on the basis of the Ministerial Decree on Cormorant Regulation from 2005; shooting permissions are given on annual basis, especially for fish ponds.

[7] Shooting permits only on Åland Islands.

[8] Population data from Gotland/Sweden and Katy Rybackie are not obtained from official sources.

For reference purposes, please cite this Baltic Sea Environment Fact Sheet as follows:
[Author’s name(s)], [Year]. [Baltic Sea Environment Fact Sheets title]. HELCOM Baltic Sea Environment Fact Sheets 2012. Online. [Date Viewed], http://www.helcom.fi/environment2/ifs/en_GB/cover/.

 

Last updated: 8 May 2012