Influence of Composition and Quantity of the Fish Age Structure Data in Catches to Determining the Relative Abundance of Generation under Incomplete Initial Information Conditions

The influence of the age structure data amount and composition on the error estimating the relative abundance of fish generation by the biostatistical method (loss from fishing) under incomplete initial information is analyzed. Using the example of the analysis of test net catches (fixed nets with mesh 35–90 mm, 31525 fish specimens) of bream Abramis brama (L.) from the Kulbyshev Reservoir (2000–2018), it is shown that to estimate the relative abundance of a generation with a given average error of 10–15%, data on its share in catches for 3–4 years (not necessarily adjacent) are sufficient. With such information available for 5–6 years, the average error in the estimate was <10%. Error is the smallest using data on the share in catches the modal age groups (for bream from the Kulbyshev Reservoir – 2⁺–6⁺). The average error in determining the relative abundance of a generation (using data for 4–5 years) did not exceed 5% in this case. The relative number underestimation of generation is more likely than its overestimation compared with calculations based on complete source data.

water reservoir, fish, generation, number, information gaps, error estimation, biostatistics