Parentage-based tagging and parentage analyses of stocked sea trout in Vistula River commercial catches

Abstract

The longest Baltic River, the Vistula, historically hosted numerous sea trout populations. However, dam construction in the twenty-first century drastically reduced the spawning migration rate. Reduced natural reproduction has resulted in a population collapse and, consequentially, a substantial reduction in catches. In response, like other Baltic countries, Poland has initiated an intensive stocking program, mainly involving smolt. Initially, stocking was conducted primarily with offspring of sea trout caught during spawning migration. Currently, due to difficulties in obtaining fish, most stocking involves fish from breeding stocks. Therefore, determining the proportion of fish derived from stocking has become an important issue. Experiments based on traditional tagging did not provide sufficient material for analysis; hence, we decided to use genetic methods based on analysis of relatedness. In this study, we performed parentage-based tagging and an analysis of the origins of parent animals used for artificial spawning in 2013, and offspring returning to the Vistula in subsequent years. We based the analysis on three different algorithms and compared the results, showing that the presented methods were effective for estimating mass stocking success. The study also indicated that a certain level of natural reproduction in the Vistula continues to occur. The proportion of sea trout from spawning in 2013 in Vistula sea trout catches from 2017 to 2018 was approximately 30%.

Microsatellites as Molecular Markers with Applications in Exploitation and Conservation of Aquatic Animal Populations

“…The parentage analysis with the close-kin mark–recapture (CKMR) method based usually on a large number of SNP loci, has recently been worked out for a few species, such as salmon, thornback ray, Raja clavate , and the Pacific white shrimp, L. vannamei , with high potential for further applications [ 457 , 458 , 459 ]. Nevertheless, microsatellites remain the most accessible marker system in the preset day kinship analyses of cultured and wild populations [ 460 , 461 , 462 ].…”