Stock dynamics assessment of major baitfish species in the lower reaches
of the Songhua River
Abstract
The stability of the ecosystem directly affects water quality and
safety, fishery production, and people’s quality of life along the
route. Therefore, a large amount of biological information on five
dominant species of baitfish, including Hemiculter leucisculus,
Acheilognathus macropterus, Rhodeus sericeus, Pseudorasbora parva, and
Squalidus argentatus, was collected in the lower reaches of the Songhua
River. The population parameters and variation rules of these fish were
evaluated. The results showed that current exploitation of fish
resources in the lower reaches of the Songhua River is excessive. The
growth rate of baitfish is accelerating, but their growth potential is
decreasing; the fish community structure is homogeneous, and the
excessively small size of fish at a low age is obvious. In addition, the
growth length coefficients of the five baitfish species were all greater
than 0.2, which indicates fast growth; the growth performance indices
were from 3.49 to 4.37. The exploitation rate of the Hemiculter
leucisculus and Squalidus argentatus minnows was greater than 0.5, and
the exploitation rates of all species except Pseudorasbora parva were
higher than Emax. To ensure the size of the main baitfish populations in
the lower reaches of the Songhua River, the mesh size of all nets should
be controlled above 45 mm. In summary, these results provide a
scientific basis for understanding the trend and growth of baitfish
resources, identifying the distribution of major commercial or
endangered fish feeding grounds in the region, and balancing ecosystem
health integrity in the lower reaches of the Songhua River.