First record of North African catfish (Clarias gariepinus) in Croatian inland waters
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1
Faculty of Agriculture, University of Zagreb, Croatia
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2
Faculty of Agrobiotechnical Sciences, Josip Juraj Strossmayer University of Osijek, Croatia
The North African catfish Clarias gariepinus (Burchell 1822) is native to South Africa, Israel, Syria and south of Turkey. It was widely introduced to other parts of Africa, Europe and Asia (Froese and Pauly, 2019). For the first time in Europe it has been introduced in Netherlands 1977 because of aquaculture purposes (Povž, 2007). Until 1990, several European countries started with North African catfish farming: Belgium, Germany, Hungary, Poland, Slovakia, Czechia and Russia (Froese and Pauly, 2019). In the same period the first occurrences of this species in inland waters have been reported, for example in 1985 in Czechia (Lusk et al., 2004). Furthermore, North African catfish have occurred in Slovenia since 1997 in gravel pits near the Hungarian border, likely as a consequence of sport fishing activities (Povž, 2007), and in 2007 was recorded in the Ovcharitza Reservoir in Bulgaria (Uzunova and Zlatanova, 2007). The status of those introductions is unknown. In Croatia, North African catfish was introduced in 2010 at the Draganići fish farm for aquaculture purposes, but, so far, there have been no records of this species in inland waters.
One specimen of North African catfish was caught on 29 September 2016 by gillnet in the Danube River (1418 rkm, near Zmajevački dunavac) by commercial fisherman during the regular fishing activity (Fig. 1.). Immediately after being caught, an undetermined specimen was frozen at -10°C and sent to laboratory of Faculty of Agrobiotechnical Sciences. In laboratory the specimen was measured for total length (TL, in cm) and weight (W, in g). Stomach content was removed, measured and prey items determined to the lowest possible systematic category. Assessment of the fish diet was based on the frequency of occurrence (F%) and numerical frequency (N%). Condition factor (CF), was calculated as W TL -3100 (Ricker, 1975).
Captured specimen was male, TL=67 cm and W= 2184 g. The stomach of this specimen was full; the dominant portion consisted of Macrophyta (F%=25), Gastropoda (N%=33, F%=25), Crustacea (N%=67, F%=25) and detritus (F%=25). Its condition factor (CF) was 0.73.
This caught specimen could be escapee from fish farms placed in the Danube River basin of Croatia or from other surrounding countries (Hungary or Czechia). For example, in Hungary this species is farmed in open ponds for the last 30 years. In Draganići fish farm in Croatia, which also belongs to the Danube River Basin, North African catfish also are placed in open ponds. North African Catfish is omnivorous fish species and its presence in inland waters may cause several negative impacts on native fish species, aquatic biodiversity and environment. Nevertheless, it is supposed that species can’t survive low winter temperatures under the European climate conditions, thus in most of European countries North African Catfish probably extinct from inland waters.
However, this record highlight needs for better regulation of farming of alien species and to setup closed recirculation systems (RAS) for new introduction of alien fish species, which is only way how to prevent such escapes in our inland waters.
Fig. 1. Captured specimen of North African catfish in the Danube River in Croatia
Acknowledgements
We would like to thank to commercial fisherman Milić Miro who provide this specimen to Faculty of Agrobiotechnical Sciences Osijek. This research was supported by EIFAAC project "Management / Threat of Aquatic Invasive Species in Europe".
References
Froese, R. and D. Pauly. Editors. 2019. FishBase. World Wide Web electronic publication. www.fishbase.org, version (02/2019).
Lusk, S., L. Hanel and V. Lusková, 2004. Red list of the ichthyofauna of the Czech Republic: Development and present status. Folia Zool. 53(2):215-226.
Povž, M. (2007). North African catfish Clarias gariepinus (Burchell, 1822). Ribič, 5, 120–121.
Ricker WE (1975) Computation and interpretation of biological statistics of fish populations. Bulletin of the Fisheries Research Board of Canada 191: 382
Uzunova, E., & Zlatanova, S. (2007). A review of the fish introductions in Bulgarian freshwaters. Acta Ichthyologica et Piscatoria, 37, 55–61.
Keywords:
Non-native fish,
Inland water,
Danube River,
North African catfish,
Stomach content
Conference:
XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019.
Presentation Type:
Poster
Topic:
THREATS AND CONSERVATION
Citation:
Piria
M,
Jelkić
D,
Gavrilović
A,
Špelić
I,
Opačak
A and
Ozimec
S
(2019). First record of North African catfish (Clarias gariepinus) in Croatian inland waters.
Front. Mar. Sci.
Conference Abstract:
XVI European Congress of Ichthyology.
doi: 10.3389/conf.fmars.2019.07.00142
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Received:
22 May 2019;
Published Online:
14 Aug 2019.
*
Correspondence:
Mx. Dinko Jelkić, Faculty of Agrobiotechnical Sciences, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia, djelkic@fazos.hr