1. Scientific name: Carassius auratus gibelio (Bloch, 1783) (Cyprinidae, Pisces)
Common names: Gibel carp, German carp, Prussian carp, silver crucian carp

Photo by Johnny Jensen (http://www.jjphoto.dk/fish_archive/carassius_gibelio.htm)

2. Identification
Body laterally compressed, covered with large cycloid scales, body length/height ratio 2.1-2.7. Colour: back greenish-grey, sides and belly silver, seldom blackish. Black dot on C base absent. Mouth relatively small, barbells absent. D relatively long. D and C dark grey, other fins light coloured (or transparent). D III-IV (14) 15-19, A II-III 5-6. Lateral line scales 29-37, vertebrae 29-31. Pharyngial teeth in one row: 4-4. Characteristically dark or almost black peritoneum and very long intestinal tract (Berg 1932, Miklesaar 1984).

3. Natural distribution
The gibel carp is native to Asia, amongst others incl. China, Taiwan, southern Manchuria, Korea, Japan, Hainan, Kolyma River, Sakhalin and the Amur Basin (Berg 1932).

4. First introduced to Estonia
In 1948, the fish was introduced deliberately to artificial fish ponds and later released into natural waterbodies (Mikelsaar 1984).

5. Invasion history in the Baltic Sea
Distribution of the species in the Baltic Sea is not documented.

6. Distribution and population dynamics in Estonian waters
During the routine coastal fish monitoring performed in the last decade, the fish has been found in the very nearshore areas (< 2m depth) in some localities in Väinameri Archipelago (Matsalu Bay) and the northern part of the Gulf of Riga (Häädemeeste, Võiste, Pärnu Bay). In the coastal strip of Häädemeeste and Võiste the species is dominating in experimental gillnet catches with a few hundreds caught per night. In Matsalu and Pärnu bays, the fish is rather common with 1-2 specimen caught per standard experimental gillnets per night.
The fish is of certain commercial interest in the NE part of the Gulf of Riga, incl. Pärnu Bay. Commercial catch of the species is unknown.

Finding locations of the gibel carp in Estonian marine waters.

7. Ecological and economical impact
The species is of commercial interest. In general, the ecological impact should be considered as negligible, probably except in a few locations in the NE part of the Gulf of Riga with high abundance of the species.

8. More information
Markus Vetemaa, e-mail: mvetemaa@ut.ee

9. References
Berg, L.S. 1932. Freshwater fishes of SSSR and neighbouring countries. Part I. Leningrad (In Russian).
Mikelsaar, N. 1984. Fishes of the Estonian SSR. Tallinn, Valgus, 432 pp (in Estonian).

1. Scientific name: Cyprinus carpio Linnaeus, 1758 (Cyprinidae, Pisces)
Common names: common carp (German carp, European carp, mirror carp, leather carp).


Photo by Leonardo Lovshin (http://nas.er.usgs.gov/fishes/accounts/cyprinid/cy_carpi.html).

2. Identification
Body laterally compressed and high, covered with large cycloid scales. D long, A short. Snout blunt, mouth large, inferior. Two pairs of barbels. Color: dark grey-blue or black-brown on back, golden yellow-brown on sides, belly yellow-grey (white or pink). Pharyngeal teeth in three rows: 1.1.3-3.1.1. Lateral line scales (32)33-40, vertebrae 36-38. D III-IV (15)16-21(22), its origin anterior to pelvic origin. A III 5(6), V I 8, P I16-18 (Mikelsaar 1984).

3. Natural distribution
Black, Caspian, Aral Sea basins, rivers from Amur to Birma in the Pacific Ocean region.

4. First introduced to Estonia
Introduction to Europe is believed to originate from Danube River. Known introduction to Estonian lakes in 1893, but perhaps the species was introduced already earlier (Mikelsaar 1984).

5. Invasion history in the Baltic Sea
Poorly known.

6. Distribution and population dynamics in Estonian waters
Last known introduction to Väinameri Archipelago (Rohuküla) in the mid 1980's. Recaptures of this release in the NE Gulf of Riga (Häädemeeste) and northern coast of the western Gulf of Finland (Hanko).
Finding records from several locations in the northeastern Gulf of Riga and Väinameri Archipelago since the end of the 1950s. Estimated commercial catch in the range of 10 individuals annually from Pärnu Bay. Experimental gillnet fishing has resulted in catch of over 10 individuals in the years of 2001 and 2002. The recent very warm summers have probably facilitated favourable conditions for successful reproduction in the shallow and relatively enclosed NE part of the Gulf of Riga.

Finding sites of carp in Estonian marine waters.

7. Ecological and economical impact
Ecological impact of this commercial species in Estonian waters is unknown, but due to low population size likely not substantial.

8. More information
Markus Vetemaa, e-mail: mvetemaa@ut.ee

9. References.
Mikelsaar, N. 1984. Fishes of the Estonian SSR. Tallinn, Valgus, 432 pp (in Estonian).

1. Scientific name: Hypophthalmichthys nobilis (Richardson, 1845) (Cyprinidae, Pisces).
Common name: The bighead carp

Photo by Thierry Dubrail (http://www.jjphoto.dk/fish_archive/aristichthys_nobilis.htm).

2. Identification
Body laterally compressed and deep with numerous scattered small black blotches. Head large. Barbels absent. Eye small, on ventral side of head. Scales small. Keels extend from pelvic base to anus. The fins of small specimens lack spines. Large specimens have a heavy, stiff, non-serrate spine at the origin of the dorsal fin and a slightly stiffened spine at the anal fin origin D II-III 7-10, A II-III 11-17, P I 15-17, V I-II 7-8. Lateral line with 92-122 scales. The pharyngeal teeth count is 4-4. Tip of P reaches to V base. The species is a filter feeder that strains planktonic organisms with long comblike gill rakers (Plikshs and Aleksejevs 1998, Robison and Buchanan, 1988, Kottelat et al. 1993).

3. Natural distribution
Native to lowland rivers of the north China plain and south China

4. First finding in Estonia
Pärnu Bay (Gulf of Riga) in 2002

5. Invasion history in the Baltic Sea
Imported to Latvia in the 1960's or later. Two records on findings from the Gulf of Riga in the early 1990s near river mouths of Salaca and Daugava (Plikshs and Aleksejevs 1998).

6. Distribution and population dynamics in Estonian waters
Single finding in 2002 only (Tl 63 cm, Tw 3.7 kg).

Finding site of the bighead carp in Estonian waters.

7. Ecological and economical impact
Unknown, but due to low abundance probably insignificant.

8. More information
Heli Shpilev, e-mail: heli@solo.delfi.ee

9. References
Plikshs, M. and Aleksejevs, E. 1998. Zivis Latvijas daba. Gandrs. Riga.
Robison, H.W., and T.M. Buchanan. 1988. Fishes of Arkansas. The University of Arkansas Press. Fayetteville. 535 pp.
Kottelat, M., A.J. Whitten, S.N. Kartikasari and S. Wirjoatmodjo, 1993. Freshwater fishes of Western Indonesia and Sulawesi = Ikan air tawar Indonesia Bagian Barat dan Sulawesi.. Periplus Editions, Hong Kong. 293 p.

1. Scientific name: Neogobius melanostomus Pallas 1811 (Gobiidae, Pisces).
Common name: Round goby, black spotted goby

Photo by G. Lashbrook and K. Johnson (http://ww2.mcgill.ca/Redpath/ricciardi/goby.html).

2. Identification.
Nape scaled completely, scales cycloid on middle and anterior nape. Head depth 0.9 - 1.2 width. Inter orbit four - fifths to almost equalling eye diameter. Angle of jaws below anterior quarter of eye. Upper lip narrowing slightly to rear, with about half lateral preorbital area. Pelvic disc 0.6 - 0.8 abdomen length, anterior membrane width very shallow, rounded, lateral lobes, if evident at all. Caudal peduncle depth about two - thirds own length. D1 VI (VVII); D2 I + 1416 (1316): A I + 1113 (1114); P 1819 (1720). Scales in lateral series 49-55 (45-57). Vertebrae 32-33 (31-34). Colour: yellowish-grey, with lateral blotches; first dorsal fin with large black spot in posterior part; breeding males are black, with median fins white-edged. (Miller 1986).

3. Natural distribution
Throughout Azov Sea and in nearshore areas of the Caspian Sea, Black Sea and Sea of Marmara. Gobies ascend tributaries of the Black and Caspian seas, incl. Dniester, Bug, Dniepr and Don rivers (Berg 1949, Miller 1986).

4. First finding in Estonia
Pärnu Bay (Gulf of Riga), 2002.

5. Invasion history in the Baltic Sea
First found in Puck Bay (Gulf of Gdansk) in 1990. If the vector for primary invasion was shipping, then this invasion should occurred already in 1987, into the harbours or shipyard basins of Gdynia because the first individual was of age 3 or 4 years (Skopra 1997). During the 1990s, the species has increased in abundance and expanded its distribution area in the primary invasion basin - Gulf of Gdansk (Sapota 2002). The species has also colonised new areas. For instance, the round goby has been found in the second half of the 1990s in the Vistula lagoon (Sapota 2002), near the Rügen island (K. Skora, pers. comm.) and found recently also in Lithuanian waters (S. Olenin, pers.comm.).

Finding site of the round goby in Estonian waters.

6. Distribution and population dynamics in Estonian waters
Single finding in April, 2002 (male, Tw 85 g, Tl 18 cm).

7. Ecological and economical impact
Being relatively large and very aggressive fish for demersal fish communities in the Baltic Sea, substantial changes may be expected in Estonian coastal waters after invasion of the round goby. Below the most important known impacts of the invasion of Neogobius in other areas are summarised.
In the Gulf of Gdansk, competition for food and displacement of several native demersal fishes (e.g., flatfishes, eelpout Zoarces viviparus, and black goby Gobius niger) by invading N. melanostomus has been suggested to take place (Skora and Stolarski 1993, K.E. Skora pers. comm.). In addition, the same authors claimed that high abundances of the round goby may cause relaxation of predation pressure on several native fish (e.g., sandeel Ammodytes tobianus and sprat Sprattus sprattus) by being more favourable food for most abundant piscivores than the above-named species. Partly as a confirmation to that, cormorants, Phalacrocorax carbo, whose population is rapidly increasing in the NE Baltic, seem to prefer round gobies in Puck Bay (Bzoma 1998).
In another invaded systems, the North American Great Lakes, populations of native benthic fishes, mottled sculpins Cottus bairdi and longperch Percina caprodes, declined sharply after the arrival of Neogobius, apparently due to competition for food and space (Jude et al. 1995). Round gobies can penetrate interstitial spaces in coarse sediments to obtain food, and therefore may become predators of lake trout eggs; they have been shown to prey on lake trout eggs in the laboratory (Chotkowski & Marsden 1999).
In case the fish stock achieves high abundance the round-goby may be commercially exploited. However, the fish hasn't received high market demands as yet (B. Draganik, pers. comm.).

8. More information
Henn Ojaveer, e-mail: henn@sea.ee

9. References
Berg, L.S. 1949.Freshwater fish of the USSR and adjacent countries. Acad. Sci. Zool Inst.
Bzoma, Sz. 1998. Te contribution of round goby (Neogobius melanostomus Pallas, 1811) to the food supply of cormorants (Phalacrocorax carbo Linnaeus, 1758) feeding in the Puck bay (Poland). Bull. Sea Fish. Inst. Gdynia 144: 39-47.
Chotkowski, M.A. and Marsden, J.E. 1999. Round goby and mottled sculpin predation on lake trout eggs and fry: field predictions from laboratory experiments. Journal of Great Lakes Research 25: 26-35.
Jude, D.J., Janssen, J. and Crawford, G. 1995. Ecology, distribution, and impact of the newly introduced round and tubenose gobies on the biota of the St. Clair and Detroit Rivers. In: Munawar M, Edsall T & Leach J (eds) The Lake Huron Ecosystem: Ecology, Fisheries and Management, pp 447-460. SPB Academic Publishing, The Hague, The Netherlands
Miller, P.J. 1986. Gobiidae. In: P.J.P. Whitehead, M.L. Bauchot, J.C. Hureau, J. Nielsen and E. Tortonese (eds). Fishes of the northeastern Atlantic and the Mediterranen: 1019-1086.
Sapota, M. 2002. Invasion of round goby (Neogobius melanostomus) from te Ponto-Caspian to te Baltic. Biomare Newsletter No. 2. pp 7.
Skora, K.E. 1997. Neogobius melanostomus. In: Baltic Research Network on Ecology of Marine Invasions and Introductions. S. Olenin and D. Daunys (eds.). INTERNET: http://www.ku.lt/nemo/mainnemo.htm
Skora, K.E. and Stolarski, J. 1993. New fish species in the Gulf of Gdansk, Neogobius sp. [cf. Neogobius melanostomus (Pallas 1811)]. Bulletin Sea Fisheries Institute Gdynia 1: 83.