The fish older than the dam

The catch was already low before the dam

The official Romanian catch of all sturgeon species was about 1,144 tonnes in the 1939/40 season. It averaged about 650 tonnes a year in 1920–39 and about 210 in 1941–50, and stayed between about 110 and 390 tonnes a year from 1941 to 1973. In 1995 it was under 8 tonnes (Navodaru et al. 1999, compiled by Reinartz 2002).

Official catch of all sturgeon species, Romania, metric tons a year, 1920–1997. Bars read from the printed graph, one per year; the graph prints two-year labels on three bars (1929/30, 1934/35, 1939/40), and its bar for 1953 is missing.

In 1972, the year the wall closed, the catch was 222 tonnes, close to the decade before (average 213 tonnes, 1962–71). The decade after averaged 111 tonnes (1973–82). It fell under 100 tonnes in 1978.

The series has one break the source does not explain: from about 1,144 tonnes in the 1939/40 season to 339 and then 126 in the next two years. A change in what was counted, such as territory or reporting, cannot be excluded. After that, it shows no abrupt fall in 1972. By 1972 the official catch was already about a third of its 1920–39 level, and belugas had been vanishing from the upper river for centuries. A second fall began in the mid-1970s. The dam, fishing pressure and everything else that changed in those years move together in this series; it cannot separate them.

What it does not say: no beluga-only annual series was found open. For the Lower Danube as a whole, annual beluga catch between 1958 and 1981 ranged from 19.7 to 240.4 tonnes, averaging 105.6 (Joint Commission figures, quoted by Reinartz 2002). In 2002 Reinartz reported that illegal and unreported fishing could, regionally, make up about half of all fish caught and up to 90 per cent of the sturgeon catch, so official figures understate it.

Spawning reaches, then and now

Below the walls, 13 spawning sites between km 755 and km 840 were listed in the Bulgarian stretch in May 2002, on gravel 9 to 22 m deep (Vassilev 2003). Kynard and colleagues placed five more potential sites between km 150 and km 600 (quoted second-hand by Vassilev; not opened).

Above the walls, the old main reach lay between km 1,766 and km 1,866. A beluga from the Romanian Danube met the first wall about 820 km short of it. By then the last beluga recorded there, a female near Štúrovo, was 47 years in the past (1925).

Caviar and the 2006 ban

CITES gave Romania yearly export quotas for beluga caviar: 1,750 kg for 1999, 3,200 kg for 2000 and 3,100 kg for 2001 (table in Reinartz 2002).

From April 2006 a joint order of Romania’s agriculture and environment ministers banned, for ten years, commercial fishing of wild sturgeon and trade in products from wild sturgeon caught in Romania. Accidental catches must be released, and live breeding fish may be taken for hatcheries with authorisation. Reports say the ban was later extended and, in 2021, made indefinite (Emerging Europe).

What changed after the ban cannot be shown here: the official series above ends in 1997, and no later series was found. The order’s number was not printed in the text read.

What the picture draws, and what it does not

• The river bed is drawn, not surveyed. No open depth profile along the Danube was found. The only published depth used is 24 m in the Cerna Gulf, km 953–955 (Nistor et al. 2021). Water level behind each wall is drawn as a step; its height is not measured here.
• The growth curve is from the Caspian. It was fitted to 5,202 aged fish of the southern Caspian (Fazli et al. 2020). No open length-at-age table for the Danube was found. Other published Caspian fits give much smaller maximum lengths: 265 cm for males and 276 cm for females, against 440 cm (Bakhshalizadeh et al. 2021).
• Distances are along the river, in the Romanian kilometre numbering with zero at Sulina. Sources differ by 1 km on the walls’ positions.
• The fish at the start is drawn just under the surface beside you, for size. Its depth in the river is not drawn from data.
• Records are few. GBIF holds only 57 records of Huso huso from Romania: 49 are tissue samples from one set in 2019, and the rest are museum specimens (1935–2007) or undated. They show who records, not where the fish are.