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Current status of feeding stocks of the kaluga sturgeon H uso dauricus G eorgi, 1775, and A mur sturgeon A cipenser schrenckii B randt, 1889, in R ussian waters
Author(s) -
Koshelev V.,
Shmigirilov A.,
Ruban G.
Publication year - 2014
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12606
Subject(s) - sturgeon , fishery , estuary , biology , juvenile , huso , ecology , fish <actinopterygii>
Summary Biological parameters of the kaluga H uso dauricus and A mur A cipenser schrenckii sturgeons have been analyzed in their foraging areas in R ussian waters. Results show that both species are now sufficiently abundant only in catches from the lower A mur R iver, its mouth, and the A mur E stuary. The largest A mur sturgeon individuals occur in the estuary, while the largest kaluga sturgeon reside in the estuary as well as in the S ea of O khotsk. Catches made in the river consist mainly of juvenile fish. The average body sizes of kaluga and A mur sturgeons in catches from the lower A mur R iver and the A mur E stuary have decreased significantly compared to records from 1929 to 1930. Between 2006 and 2011, the proportions of mature kaluga and A mur sturgeons in the river catches averaged 2.9 and 5.1%, respectively, and at its mouth and in the estuary by 42.6 and 32.8%, respectively. Abundance of kaluga sturgeon (age >1 year) in the lower A mur and the estuary in 2011 reached 345 000 individuals at a biomass of 7110 tonnes (t). Abundance of A mur sturgeon (age >1 year) in the same area and time reached 289 000 individuals at a biomass of 1946 t. The main stocks of the respective species (324 300 individuals or 94% in K aluga, 263 570 individuals or 91.2% in A mur sturgeon) are concentrated in the A mur E stuary. To restore their populations in the A mur, a ban on all types of commercial fishing at the spawning grounds and juvenile foraging grounds should be implemented. It is also necessary to increase the number of hatchery‐reared juveniles and allow them to grow to a greater body size before release into the A mur.