Hemimysis anomala - Bloody-red shrimp

The bloody-red shrimp Hemimysis anomala occurs naturally in the Caspian Sea, the Black Sea and in the Don River (Russia). This shrimp-like crustacean prefers a habitat with lots of loose stones or clayey banks with cavities ^[2].

Later, the species was introduced as fish food in a couple of waters in the former Soviet Union (including Lithuania). However, populations expanded and soon reached the Baltic Sea ^[2].

First observation in Belgium

On the 12th of October 1999, the bloody-red shrimp was observed for the first time in the brackish water pond 'Galgenweel', close to the Port of Antwerp [3]. This pond is connected to the Sea Scheldt via a sluice, so the water can drain off when the level gets too high.

Spreading in Belgium

Besides the observations in the ‘Galgenweel’ pond, the species was found in several other places. In 2004, a specimen was found in a cooling water tank of the chemical company BASF, located in the Port of Antwerp [4], and two years later – in 2006 – two more sightings came from the Scheldt river near the Belgian-Dutch border [5]. This species is rarely detected in the Zeeschelde, which may indicate that the prevailing environmental conditions are not considered optimal for this species [6].

The species has also been spotted in a ditch near the port of Ostend [7, 8]. Other (limited) observations were made in Lake Gavermeer (Kortrijk), Lake Donkmeer (Overmere), the Scheldt at Dendermonde and the Damme Canal in Hoeke and Damme [9].

Spreading in neighbouring countries

Hemimysis anomala spreads surprisingly quickly despite its limited dispersal capacity. It cannot be dispersed by birds and can barely swim upstream. Until the 1960s, it could only be found in the mouths of rivers flowing into the Black Sea and the Sea of Azov. In 1960, the species was deliberately introduced into lakes in Lithuania. From there, the bloody-red shrimp could move downstream to the Baltic Sea. In 1992, there was the first observation in Finland. Sweden (1995) and Poland (2002) followed. The species was also found in Germany (1998) and was reported in the Czech Republic five years later (2003). In the other direction, the species spread to the Danube-Rhine system which connects the Black Sea with the North Sea [10].

The bloody-red shrimp was first observed in the Netherlands in June 1997, near Amsterdam [11]. Scientists found the species in fish stomachs from the Rhine (near Nijmegen) and the Haringvliet (Rotterdam) [12]. Individuals of this species were also observed in the Biesbosch National Park (located between the Maas and Rhine rivers) and in the Maas and Waal rivers [13]. Except for the Haringvliet, the sites are all freshwater environments.

In 2005, the bloody-red shrimp was observed in the United Kingdom [14]. In the UK, it has long been a mystery how the species has colonised the closed areas of Nottinghamshire. Two possible options are considered: (1) the annual international rowing competition, with the rowing boats bringing in stowaways, or (2) the species was deliberately introduced as live bait by anglers [14]. In April 2008, this crustacean was found for the first time in the heart of Ireland, in the Shannon River Basin District, where it is now considered to be well established [15].

It is expected that new populations will become established in other brackish water basins along the European coast [3, 11, 12]. In 2004 and 2005, high numbers of the species were observed near Gdansk (Poland, Baltic Sea) [2]. The bloody-red shrimp is also on the rise in the Great Lakes region of the USA. In addition to the Great Lakes, where the species has been present for some time, the bloody-red shrimp was also found in August 2009 in Lake Oneida, near Lake Ontario, which was the first discovery in the USA outside of the Great Lakes [16

The bloody-red shrimp arrived in our region from the Netherlands. In the Netherlands, it may have arrived in two different ways: via area expansion from the Danube or Rhine, or via ballast water from ships coming from the Black Sea or Baltic region ^[13].

Thanks to several characteristics, the bloody-red shrimp can colonise new areas quickly. The species tolerates salinity levels between 0.5 and 18 PSU ^[17]. By comparison, the seawater in the North Sea has a salinity of about 35 PSU. This species will therefore not be able to survive in seawater. Furthermore, the bloody-red shrimp is an efficient omnivore and can thrive in both still and flowing water ^{[3, 13]}.

The bloody-red shrimp performs vertical diurnal migration. This means that during the day, these animals stay near the bottom (up to 30 metres deep), seeking the safety of crevices and cavities. At night, they rise in large numbers in the water column, even up to the surface ^[13]. The bloody-red shrimp, therefore, needs during the daytime some form of shelter, like crevices or cavities ^[2]. Hence, this type of habitat must be present for the survival of this species. However, this is not usually a problem, as most ponds have such shelters.

Hemimysis anomala does not tolerate salt levels above 18 PSU. Thus, this crustacean will only be able to spread in fresh and brackish environments. Given that Western Europe has a highly interconnected network of streams, rivers and canals, the species can still greatly expand its habitat in this area. Also, the areas of origin of this species – the Caspian and Black Seas – have a lower salt concentration (2-20 PSU) than the North Sea (34-35 PSU) ^[17].

The bloody-red shrimp is an omnivore with a preference for water fleas (Cladocera) ^{[3, 12, 13]}. Scientists have noted, among other things, a sharp decline in water fleas, seed shrimp (Ostracoda), wheel animals or rotifers (Rotifera) and invertebrate predators in waters where the bloody-red shrimp is found ^[13]. As a result, the introduction of this exotic species could affect the species composition of the zooplankton (animal organisms living freely in the water column) ^{[3, 12, 13]}.

In general, zooplankton numbers and their diversity decrease after an invasion by bloody-red shrimp, as has already been observed in several areas in the Netherlands ^[13]. Since zooplankton, and especially water fleas, are the main grazers of algae, this can cause large algal blooms, which can lead to a sharp decline in water quality. On the other hand, this can be counteracted by the larvae of the bloody-red shrimp themselves, as they are very efficient grazers. However, water quality may still be compromised as the larvae can change the chemical composition of the water. The bloody-red shrimp is a potential food source for many species of fish. This type of predation could limit the number of bloody-red shrimp. However, it is never certain whether a predator will switch to a new food source, which may lead to a decrease in the fish population due to the reduced concentration of indigenous zooplankton (their current prey). In this way, the entire food chain is disrupted and such tendencies may impact the higher trophic levels (predatory fish and birds that feed on these fish) ^{[18, 19]}

Adults typically measure between 5.5 and 12.5 mm in length and are thus, on average, somewhat smaller than two other freshwater species, namely the native Neomysis integer and the non-native Limnomysis benedeni. There are often strong spots of red pigmentation on the body, which gave this species its nickname, the ‘bloody-red shrimp’. For a correct determination, an overview of the detailed characteristics can be found in the literature ^[11].

These crustaceans reproduce sexually and display active brood care. As is the case for all mysid shrimps, the females keep the few eggs (maximum 30) with her in a brood pouch or marsupium ^[14]. Furthermore, these shrimp-like crustaceans are omnivorous and live in deep to sublittoral water ^{[20, 21]}. In the Black Sea, shrimps usually live at depths of 6 to 10 metres, with maxima of 20 metres, and avoid direct light ^[21].

[1]          World Register of Marine Species (WoRMS) (2020). Hemimysis anomala G.O. Sars, 1907. [http://www.marinespecies.org/aphia.php?p=taxdetails&id=120025] (2020-11-17).

[2]          Janas, U.; Wysocki, P. (2005). Hemimysis anomala G.O. Sars, 1907 (Crustacea, Mysidacea): first record in the Gulf of Gdansk. Oceanologia 47(3): 405-408. [http://www.vliz.be/en/imis?module=ref&refid=77258]

[3]          Verslyke, T.; Janssen, C.; Lock, K.; Mees, J. (2000). First occurrence of the Pontocaspian invader Hemimysis anomala (Sars, 1907) in Belgium (Crustacea: Mysidacea). Belg. J. Zool. 130(2): 157-158. [http://www.vliz.be/en/imis?module=ref&refid=2678]

[4]          Fockedey, N. (2008). Persoonlijke mededeling

[5]          Fockedey, N.; Mees, J. (2003). Marine Biology Section - Ugent. Mysid shrimp populations in the Scheldt estuary. [http://www.vliz.be/en/imis?module=dataset&dasid=46]

[6]          Soors, J. (2019). Persoonlijke mededeling

[7]          Boets, P.; Lock, K.; Goethals, P.L.M. (2012). Assessing the importance of alien macro-Crustacea (Malacostraca) within macroinvertebrate assemblages in Belgian coastal harbours. Helgol. Mar. Res. 66(2): 175-187. [http://www.vliz.be/en/imis?module=ref&refid=206987]

[8]          Boets, P.; Lock, K.; Goethals, P.L.M. (2011). Shifts in the gammarid (Amhipoda) fauna of brackish polder waters in Flanders (Belgium). J. Crust. Biol. 31(2): 270-277. [http://www.vliz.be/en/imis?module=ref&refid=211034]

[9]          Waarnemingen afkomstig van Waarnemingen.be, e.i.v.N.S.v.e.d.S.N. (2019). Kaspische aasgarnaal - Hemimysis anomala G.O. Sars, 1907. [https://waarnemingen.be/species/21076/] (2019-07-09).

[10]        Audzijonyte, A.; Wittmann, K.J.; Väinölä, R. (2007). Tracing recent invasions of the Ponto-Caspian mysid shrimp Hemimysis anomala across Europe and to North America with mitochondrial DNA. Divers. Distrib. 14(2): 179-186. [http://www.vliz.be/nl/catalogus?module=ref&refid=300960]

[11]        Faasse, M. (1998). The Pontocaspian mysid Hemimysis anomala Sars, 1907, new to the fauna of The Netherlands. Bull. Zool. Mus. Univ. Amsterdam 16(10): 73-76. [http://www.vliz.be/en/imis?module=ref&refid=7362]

[12]        Kelleher, B.; Van der Velde, G.; Wittmann, K.J.; Faasse, M.A.; Bij de Vaate, A. (1999). Current status of the freshwater Mysidae in the Netherlands, with records of Limnomysis benedeni Czerniavsky, 1882, a Pontocaspian species in Dutch Rhine branches. Bull. Zool. Mus. Amsterdam 16(13): 89-98. [http://www.vliz.be/en/imis?module=ref&refid=5642]

[13]        Ketelaars, H.A.M.; Lambregts-Van de Clundert, F.E.; Carpentiear, C.J.; Wagenvoort, J.; Hoogenboezem, W. (1999). Ecological effects of the mass occurence of the Pontocaspian invader, Hemimysis anomala G.O. Sars, 1907 (Crustacea: Mysidacea), in a freshwater storage reservoir in the Netherlands, with notes on its autecology and new records. Hydrobiologia 394: 233-248. [http://www.vliz.be/en/imis?module=ref&refid=7360]

[14]        Holdich, D.; Gallacher, S.; Rippon, L.; Harding, P.; Stubbington, R. (2006). The invasive Ponto-Caspian mysid, Hemimysis anomala, reaches the UK. Aquat. Invasions 1(1): 4-6. [http://www.vliz.be/en/imis?module=ref&refid=97409]

[15]        Minchin, D.; Boelens, R. (2010). Hemimysis anomala is established in the Shannon River Basin District in Ireland. Aquat. Invasions 5(Suppl. 1): 71-78. [http://www.vliz.be/nl/catalogus?module=ref&refid=300965]

[16]        Brooking, T.E.; Rudstam, L.G.; Krueger, S.D.; Jackson, J.R.; Welsh, A.B.; Fetzer, W.W. (2010). First occurrence of the mysid Hemimysis anomala in an inland lake in North America, Oneida Lake, NY. J. Great Lakes Res. 36(3): 577-581. [http://www.vliz.be/nl/catalogus?module=ref&refid=300964]

[17]        Bacescu, M. (1969). Otryad mizidy - Mysidacea Boas (Mysidacea Boas in the Black Sea), Opredelitel fauny Chernogo I Azovskogo morey, volume 2 (A key to Black Sea and Azov Sea fauna). 2. Naukova Dumka Publishing: Kiev, Ukraine: pp. 363-381. [http://www.vliz.be/nl/catalogus?module=ref&refid=300962]

[18]        Ricciardi, A.; Avlijas, S.; Marty, J. (2012). Forecasting the ecological impacts of the Hemimysis anomala invasion in North America: Lessons from other freshwater mysid introductions. J. Great Lakes Res. 38: 7-13. [http://www.vliz.be/nl/catalogus?module=ref&refid=297377]

[19]        Pérez-Fuentetaja, A.; Wuerstle, J. (2014). Prey size selection and feeding ecology of an omnivorous invader: Hemimysis anomala. J. Great Lakes Res. 40(2): 257-264. [http://www.vliz.be/nl/catalogus?module=ref&refid=300968]

[20]        Mauchline, J. (1980). Part II: The Biology of Mysids, in: Blaxter, J.H.S. et al. Advances in Marine Biology., 18. Academic Press: New York, USA: pp. 369. [http://www.vliz.be/en/imis?module=ref&refid=121150]

[21]        Salemaa, H.; Hietalahti, V. (1993). Hemimysis Anomala G.O. Sars (Crustacea, Mysidacea) - Immigration of a Pontocaspian Mysid into the Baltic Sea. Ann. Zool. Fenn. 30(4): 271-276. [http://www.vliz.be/nl/catalogus?module=ref&refid=300970]

VLIZ Alien Species Consortium (2020). Hemimysis anomala – Bloody-red shrimp. Non-native species of the Belgian part of the North Sea and bordering estuaries anno 2020. Flemish Institute for the Sea (VLIZ). 6 pp.