# Growth and Development Dynamic of the Lena Population Siberian Sturgeon (Acipenser baerii Brandt, 1869) Bred in a Recirculating Aquaculture System

## TL;DR

This study tracks the growth of Siberian sturgeon in a controlled aquaculture system to improve breeding practices and sustainability.

## Contribution

The study identifies key morphological predictors for body weight and optimal breeding selection timing in Siberian sturgeon.

## Key findings

- Growth rates decline with maturity, shifting focus to reproductive readiness.
- Body weight can be reliably predicted using morphological measurements like body height and thickness.
- Optimal breeding selection occurs at 2 years and 2 months or older.

## Abstract

Siberian sturgeon is a highly promising fish for commercial farming due to its quick weight gain and strong ability to survive in controlled environments. We explored how these fish grow and develop over time in a closed-loop water system to refine breeding strategies. The results showed that growth rates decreased as the fish matured, shifting focus from rapid expansion to reproductive readiness. Body weight varied more widely than other physical traits, but the fish’s size and shape were strongly linked to weight, allowing reliable predictions through simple formulas. Certain traits, like body height and thickness, show promise as predictors for future development of contactless weight assessment systems using technologies such as computer vision. The findings also suggest the timing for selecting the healthiest individuals for breeding. Overall, this information can help optimize farming practices, making sturgeon production more efficient and sustainable for food industries.

Siberian sturgeon (Acipenser baerii Brandt, 1869), characterized by its rapid mass accumulation and high survival rate under industrial breeding conditions, is one of the most promising aquacultural species. This research aimed to study the growth and development of farmed Siberian sturgeon (Acipenser baerii Brandt, 1869) to improve breeding programs. This research was conducted at the Federal Research Center for Animal Husbandry named after Academy Member L.K. Ernst and focused on the Lena population broodstock of Siberian sturgeon of the April 2022 generation (n = 98), grown in a recirculating aquaculture system (RAS). The experiment took into account body weight (W, g) and eleven morphological measurements: L—absolute length (cm); LR—fish body length increase (cm/day); l—commercial length (cm); L2—fork length (cm); HL—head length (cm); PV—pectoventral distance (cm); VA—ventroanal distance (cm); pl1—peduncle length (cm); H—body height (cm); h—peduncle height (cm); SC—body thickness (cm); GC—body circumference (cm); and Cc—peduncle circumference (cm). These measurements were taken from the same sample of fish at five different time points, all belonging to the same generation and approximately the same age. Measurements were taken every 3 to 9 months: 1 y (group G1), 1 y. 5 m. (group G2), 2 y. 2 m. (group G3), 2 y. 5 m. (group G4), 3 y. 2 m. (group G5), and 3 y. 5 m. (group G6). To evaluate the rate of growth and development, relative speed of growth (SGR) and relative speed of lengthening (SLR) during the observation period were determined. To characterize the fish’s exterior, we evaluated Fulton’s condition factor (KF) and the leanness index (Q). With increasing age, there was a significant (p < 0.01) decline in both SGR (from 0.454 to 0.065 g%/day) and SLR (from 0.132 to 0.028 cm%/day), which reflects changes in the fish’s physiological processes tied to the transition from the growth phase to the puberty phase. Relatively large variability was observed in body weight (Cv = 19.7–30.4%) compared to morphological measurements (Cv = 5.7–14.9%). Correlations between morphological measurements and the body weight of the fish varied from low to high (r = 0.22–0.97). Equations that allow for very precise (coefficient of determination R2 = 0.800–0.933) estimation of the fish’s body weight based on morphological measurements were developed. The most preferable predictors were measurements of H (R2 = 0.931), SC (R2 = 0.933), and L2 (R2 = 0.930). These morphological measurements are promising candidates for future development of contactless live weight detection using computer vision and machine learning algorithms. The study of live weight conjugacy at different ages showed that the best time to use this measurement to select fish for reproduction is at the age of 2 y. 2 m. or older. Acquired data can be used for the development and improvement of programs for the selection and breeding of Siberian sturgeon grown in a recirculating aquaculture system.