Seine River Demersal Habitat
This taxon is one of a number of demersal species in the Seine River system of Western Europe. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton
The Marne and Yonne exhibit the greatest torrential flows, due to the percentage of their courses underlain by impermeable strata, in combination with the river gradients. Although the Loing manifests the highest percentage of impermeable strata of all the tributaries, its low gradient mitigates against torrential velocities. Thus the majority of the Seine and its tributaries exhibit a relaxed generally even flow rate.
Seine water pollutant loads of heavy metals, nutrients, sediment and bacteria are relatively high, especially influnced by wastewater and surface runoff from Paris and its suburbs. Parisian pollutant loadings are noted to be particularly high during periods of high rainfall, not only due to high runoff, but also from the inadequate sewage treatment facilities in periods of high combined wastewater/stormwater flow.
Heavy metal concentrations at Poses weir reveal the following levels: copper, 1.9 milligrams per liter; cadmium, 32 mg/l; and lead, 456 mg/l. Concentrations of zinc are also quite high, making the Seine Estuary one of the most highly contaminated estuaries in the world with respect especially to lead and cadmium. Significant amounts of toxic pollutants are also attached to sediments deposited in the Seine during the last two centuries, including mercury, nickel, chromium, toluene, DDT and a variety of herbicides and pesticides. Downriver from Paris, significant quantites of ammonium are discharged into the Seine from effluent of the Achères wastewater treatment plant.
There are a total of 37 fish species inhabiting the Seine, and another two taxa that are known to have been extirpated in modern times. Two of the largest aquatic fauna known to have lived in the Seine are now locally extinct: the 500 centimeter (cm) long sturgeon (Acipenser sturio) and the 83 cm long allis shad (Alosa alosa).
The largest extant native demersal (species living on or near the river bottom) taxa in the Seine are:
the 133 cm European eel (Anguilla anguilla);
the 150 cm northern pike (Esox lucius);
the 120 cm sea lamprey (Petromyzon marinus); and,
the 152 cm Burbot (Lota lota).
Habitat and Ecology
Males reproduce for the first time at 10-12 years, females at 14-18. There are indications for a reproduction at two year intervals for males and 3-4 years for females in April-July. Adults do not eat during migration and spawning. The distance of the spawning migration seems to be positively correlated with water level, and a distance of 1000 km or more may be covered during years of high water. Spent fishes immediately return to the sea (FAO 2009).
Potential spawning grounds have been mapped. Juveniles migrate downstream and are present in upper estuary at one year old. They continue a slow downstream migration and penetrate the sea at 2-3 years. For the next 4-6 years, they leave the sea to enter the lower estuary at summer time where movements and feeding were determined. At sea, this species feeds on a variety of molluscs, crustaceans and small fish. Atlantic population feed benthically.
Water temperature and chemistry ranges based on 1 sample.
Depth range (m): 89 - 89
Temperature range (°C): 7.020 - 7.020
Nitrate (umol/L): 8.857 - 8.857
Salinity (PPS): 35.129 - 35.129
Oxygen (ml/l): 6.192 - 6.192
Phosphate (umol/l): 0.765 - 0.765
Silicate (umol/l): 4.624 - 4.624
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From 5 to 60 meters.
Habitat: demersal. Amphihaline and potamodromous fish frequenting litoral zones. Juveniles found both in estuaries and in the sea (Ref. 2163). This species is usually solitary. Becoming rare (Ref. 4537). Feeds on crustaceans, molluscs, polychaete worms and small fishes. Eggs deposited on sand or gravel. A long-lived and slow-growing species (Ref. 9988). Utilized fresh and frozen, and also for caviar; eaten steamed, pan-fried, broiled, boiled, microwaved and baked (Ref. 9988).
Life History and Behavior
Molecular Biology and Genetics
Statistics of barcoding coverage: Acipenser sturio
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
This species now remains in just one location, where 27 spawning grounds (less than 10 km²) remain potentially accessible (the major threat to this species is bycatch). As this species continues to be caught as bycatch, the population is still decreasing.
- 1996Critically Endangered
- 1994Endangered(Groombridge 1994)
- 1990Endangered(IUCN 1990)
- 1988Endangered(IUCN Conservation Monitoring Centre 1988)
The size of the population today is much smaller (approximately 20-750 native wild adult fish, based on an assessment of the size the cohort before they leave the estuary). There are more individuals from stocking (7,000 in 2007; 80,000 in 2008; and 46,000 in 2009) (Rouault et al. 2008; Rochard 2010). These have not yet bred in the wild and first breeding (from the releases of 1995) is expected by 2014, F1 generation of 2007 and later releases around 2021. The limiting factor is the availability of females which won't reproduce until ~2016 (Rochard, pers. comm).
Restocking was initiated in 1995 and later in 2007 until 2009. Survival rate for the 1995 stocking is 3-5%; the survival rate for recent releases is unknown. For the first time in 2007, progenies were obtained from farmed specimen (Williot et al. 2009).
There is a fisheries awareness programme co-ordinated between National Fishermen Associations in Atlantic North Sea and WWF.
This species was listed on CITES Appendix II in 1975, and moved to Appendix I in 1983.
Relevance to Humans and Ecosystems
European sea sturgeon
The European sea sturgeon (Acipenser sturio), also known as the Atlantic sturgeon, Baltic sturgeon or common sturgeon, is a species of sturgeon found on most coasts of Europe. It is andromous and breeds in rivers. It is currently a critically endangered species.
The wedge-shaped head of this sturgeon ends in a long point. There are many sensitive barbels on the facial area. The dorsal fins are located very far back on the body. Five longitudinal lines of large osseous plates are found on the body of the fish. The stomach is yellow and the back is a brownish grey.
This sturgeon can reach 6 m (20 ft) and 400 kg (880 lb) in weight, but a more common length is 1.25 m (4 ft 1 in). They can reach an age of 100 years, and have a late sexual maturity (12 to 14 years for the males and 16 to 18 years for the females).
They are found on the coasts of Europe, except in the northernmost regions, and have rarely even been known to cross the Atlantic Ocean to the coasts of North America. Like many other sturgeons, they spawn in the rivers inland from the coast. Despite their estimated range of distribution, they have become so rare that they only breed in the Garonne river basin in France. Conservation projects involving this species include reintroductions based on specimens from aquaculture with the first releases in 1995. For example, some 50 sturgeons were reintroduced in the Rhine near Nijmegen in 2012.
At the beginning of the 19th century, these fish were used extensively to produce caviar, but have been a protected species in Europe since 1982.
- Gesner, J., Williot, P., Rochard, E., Freyhof, J. & Kottelat, M. (2010). "Acipenser sturio". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature. Retrieved 24 February 2013.
- Froese, Rainer and Pauly, Daniel, eds. (2005). "Acipenser sturio" in FishBase. 10 2005 version.
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