Russian Sturgeon Larval Rearing and Feeding Tables: A Technical Guide for Hatchery Production in RAS

Introduction

Russian sturgeon (Acipenser gueldenstaedtii) also called Ossetra, Diamond or Danube sturgeon, is an important species in hatchery production because it serves both commercial aquaculture for human use and conservation-oriented rehabilitation and stock enhancement efforts in parts of its native range (Chebanov and Galich 2013; Chebanov et al. 2011). This dual role increases the need for practical hatchery guidance that is both biologically sound and easy to use in daily operations, especially involving the sensitive early-life stages when survival and later performance can be influenced by rearing conditions and feed management (Chebanov and Galich 2013).

The tables assembled in this factsheet were developed as a comprehensive quick-reference resource for hatchery personnel, students, and aquaculture practitioners working with Russian sturgeon larvae and post-larvae under controlled recirculating aquaculture system (RAS) culture conditions (Chebanov and Galich 2013; Memiş et al. 2009; Conte et al. 1988). Their purpose is not to replace the underlying manuals and studies, but to provide the most operationally important information in a format that can be consulted quickly during routine hatchery work (Chebanov and Galich 2013; Conte et al. 1988). For users who need greater technical detail, justification, or methodological background, the original source documents cited throughout the tables are provided and should be consulted directly (Chebanov and Galich 2013; Chebanov et al. 2011; Memiş et al. 2009; Conte et al. 1988).

The scope of the tables is intentionally broad because successful Russian sturgeon larviculture depends on the interaction of multiple environmental, biological, and operational factors (Chebanov and Galich 2013; Chebanov et al. 2011). Accordingly, the tables summarize recommended larval rearing environment and system targets, including temperature, dissolved oxygen, pH, total hardness, alkalinity, mineral composition, nitrogenous waste limits, salinity, photoperiod, light intensity, tank color, water depth, and flow regime (Chebanov and Galich 2013; Chebanov et al. 2011). These are the core conditions that shape larval growth, behavior, feeding response, physiological stability, and survival during the transition from endogenous nutrition to active feeding (Chebanov and Galich 2013).

This factsheet also provides stocking-density guidance based on tank bottom surface area rather than water volume alone, which is especially meaningful for Russian sturgeon because larvae and early juveniles are strongly bottom-oriented fish whose rearing performance depends heavily on usable benthic space (Chebanov and Galich 2013; Conte et al. 1988). In addition, the feeding tables combine days post-hatch, average size, live-feed progression, microdiet introduction, and feed-transition strategy into a practical culture sequence designed for direct hatchery application (Memiş et al. 2009; Chebanov and Galich 2013). This is very important because Russian sturgeon larval success depends on the correct timing of first feeding, proper feed presentation near the tank bottom, and adjustment of ration and feed type as the fish grow and transition onto formulated diets (Memiş et al. 2009; Conte et al. 1988).

A particular strength of this document is that it integrates information from a number of successful and well researched hatchery manuals with species-relevant experimental and applied culture observations (Chebanov and Galich 2013; Chebanov et al. 2011; Memiş et al. 2009). The FAO sturgeon hatchery publications provide the larger framework for larval rearing, water management, feeding transitions, and release-oriented hatchery considerations, while the work of Memiş and colleagues contributes practical developmental, growth, and feeding benchmarks under Russian sturgeon culture conditions (Chebanov and Galich 2013; Chebanov et al. 2011; Memiş et al. 2009, Kornienko et al. 2020). Conte’s white sturgeon hatchery manual also remains valuable because many early-life-stage culture practices are transferable across multiple sturgeon species, their specific hatchery systems, and reinforce practical guidance on tank management, first feeding, and early rearing strategies for Russian sturgeon (Conte et al. 1988).

Combined with the additional referenced materials, these tables are intended to function as a field-ready hatchery reference: broad enough in scope to cover the major components of Russian sturgeon larval and post-larval culture, yet concise enough to support rapid decision-making in day-to-day hatchery use (Chebanov and Galich 2013; Chebanov et al. 2011; Memiş et al. 2009; Conte et al. 1988). Information on later life stages and growout for aquaculture or conservation release is beyond the scope of this fact sheet, but is available in the references listed (Chebanov et al. 2011).

Tables

Table 1. Larval Rearing Expectations Based on RAS System Targets
Parameter	Recommended target / operating range	Why it matters in larval tanks	Primary resource ^a
First feeding onset	Begin exogenous feeding when yolk absorption is nearly complete; commonly about 7.5 d at 21°C, 8 d at 19°C, 9.5 d at 17°C, and about 12 d at 15°C.	Correct timing determines when live feed can begin. Must avoid overfeeding to maintain good water quality	[1], [2], [3] [8]
Temperature	Hold larval-rearing water near 17-19°C during the first-feeding period; avoid abrupt changes in temperature. Increase temperatures to 20-22°C 12-18 dph	Stable temperature supports yolk utilization, feeding onset, and reduces refusal of first feeds.	[1], [2], [3], [8]
Dissolved oxygen / aeration	Maintain oxygen >5ppm with gentle, continuous aeration; avoid dead zones along the bottom.	Larvae aggregate near the bottom, so oxygen must remain adequate at the tank floor. Tank depth 12”-18” best.	[1], [2], [7], [8]
Light regime	Use subdued lighting and a regular 16/8 light/dark photoperiod; Prelarvae- low light at 2-10 lux, increase to 80-100 lx following exogenous feeding. Can increase again < 800 lx, Avoid intense direct light over larval tanks.	Prelarvae and larvae show strong behavioral responses to light and tend to seek darker bottom/corner areas. Low light may improve bottom feeding.	[1], [5], [8]
Tank interior / hydraulics	Use smooth circular or rectangular larval tanks with calm circulation, low shear, and a clean bottom feeding zone. Prelarvae use 3 L/min, postlarvae increase to 10 L/min	Larvae are benthic; Modest waterflow is essential to stimulate feeding, excessive flow reduces bottom feeding efficiency and increases stress.	[1], [2], [3], [7]
Stocking basis	Calculate density using tank bottom surface area. Practical stocking rates vary. Stock prelarvae/ larvae at baseline density of 500/ft²; for both circular and rectangular tanks.	Bottom surface area is better measure of larval space requirements than water volume. Reduce stocking around 20 and 35 dph as needed to limit crowding and cannibalism.	[1], [2], [3], [8], [9]
Feed delivery location	Provide Artemia and other first feeds at the tank bottom or along the perimeter; feed in small, frequent portions. 4-5 times per day ad libitum. May reduce feeding intervals as needed after transition to microdiet.	Important to sample larvae to confirm feed acceptance and ingestion. Larvae orient strongly to bottom feeding and rely heavily on olfactory cues.	[1], [3], [7]
Sanitation / solids control	Remove dead larvae, debris, and uneaten feed before subsequent meals; keep the bottom visibly clean.	Clean bottoms improve feed detection and reduce water-quality deterioration.	[1], [2], [3]
Transition to microdiet	Introduce sinking microdiet during co-feeding, then reduce live feed gradually as acceptance improves.	A staged, overlapping transition reduces starvation risk and supports uniform adaptation to artificial feed.	[1], [3], [6], [7]

a) Resource numbers correspond to the 8-item reference list. ↲

Table 2. Recommended environmental targets for larval production in RAS
Parameter	Recommended target / operating range	Why it matters in larval tanks	Primary resources ^a
Temperature	17-19 °C at first feeding; 18-22 °C acceptable during larval rearing	First feeding in Russian sturgeon is commonly reached around 8-10 dph at this temperature range. Keep daily swings ≤2 °C.	[1], [3]
Dissolved oxygen	5 mg/L ≥ saturation	Low oxygen tolerance is poor at first feeding; keep concentration stable	[1], [4], [9]
pH	7.0-8.0	Keep pH stable with well buffered water, especially after feeding live/inert feeds.	[4]
Total hardness	50-400 mg/L as CaCO3; target ~100-200 mg/L	Use moderately hard, buffered freshwater rather than very soft water.	[4]
Alkalinity	100-400 mg/L as CaCO3	Supports pH stability as a buffering agent	[4]
Mineral composition	Freshwater containing both calcium and magnesium; not demineralized water	No specific ideal Ca:Mg ratio; target buffered water with both Ca and Mg present.	[4]
Nitrogen limits	NH3 <0.01 mg/L as N; NH4+ ≤0.05 mg/L; nitrite <0.1 mg/L as N; nitrate <10 mg/L	Larvae are sensitive to various chronic sublethal nitrogen compounds.	[4]
Salinity	0-0.5 ppt for routine hatchery larviculture	Optional 1-2 ppt sometimes used for on-growing as advanced fingerlings. Not a standard commercial requirement.	[1], [9]
Photoperiod	Endogenous feeding stage 0-6 dph, use 12L:12D, Change to 16L:8D, when exogenous feeding begins 7dph+; best to include 15 min dawn/dusk if possible,	Russian sturgeon larvae have been cultured successfully using 16 h daylight + 4 h dim + 4 h dark; Avoiding longer light periods will improve growth	[1], [5]
Light at water surface	Endogenous feeding use 2-10 lux; increase to at exogenous feeding, 7-10dph, 80-100 lx; After 10dph keep larvae <800 lux	Russian-sturgeon prelarvae should use 450 lux day, 10 lux dim, <1 lux dark. Do not use harsh bright lighting.	[1], [5]
Tank color	At 8dph (first feeding) use green or grey interior surfaces; avoid white	This is specifically recommended for sturgeon larvae when feeding in hatchery tanks. Blue may work, but not reported as a useful option.	[1], [9]
Water depth	20 cm 0-10 dph; can increase later as fish gain swimming ability	The FAO prelarval norm is 20 cm; shallower water can help with live feeding efficiency.	[1], [3]
Water flow	8-9 L/min early; increase as biomass and feeding increases	One Russian-sturgeon study used 5 L/min in larval tanks; FAO prelarval norm is 8-9 L/min.	[1], [3]
Stocking density (after hatching)	Prelarvae 500/ft2 changes to 250 /ft² after exogenous feeding begins. About 8dph	These are FAO and U.S. tray/tank averages converted from per-m² values. Tank depths 30-40 cm	[1], [2], [9]
Best 3 Artemia enrichments	1) DHA-rich HUFA enrichment, 2) Arthrospira/Spirulina enrichment, 3) Probiotic bioencapsulation	DHA- and other PUFA/HUFA enrichment is the most established; the Arthrospira result is Russian-sturgeon-specific and recent.	[1], [6]

a) Resource numbers correspond to the 8-item reference list. ↲

Table 3. Practical Stocking Schedule for Russian Sturgeon Larvae Reared in RAS Tanks
Stage	Collated dph*	Size	Stocking density	Fish/ft²	Ref.
Prelarvae	0–8	Yolk-sac stage, before first feeding. 0.013-0.023	5,000 fish/m²	465	[1], [3]
Larvae at first feeding	8–11	≈0.03–0.04 g (estimated)	≈2,500 fish/m²*	≈232	[1], [3]
Early larvae	12–16	0.04–0.07 g	2,500 fish/m²	232	[1], [3]
Larvae / post-larvae	15–30	0.07–0.5 g	2,000 fish/m²	186	[1], [3]
Post-larvae	31–35	0.6–1.0 g	1,500 fish/m²	139	[1], [3]
Fry	36–56	1.1–3.0 g	1,000–500 fish/m²	93–46	[1], [3]
Fry	57–75	3.1–5.0 g	400 fish/m²	37	[1], [3]
Large fry / juveniles	75+	5.1–30.0 g	300–150 fish/m²	28–14	[1]

Table 4. Bottom-area examples from cited sources
Tank example	Bottom dimensions only	Bottom area (m²)	Bottom area (ft²)	Ref.
Prelarval tank / tray	2–4 m² reported directly	2–4	21.5–43.1	[1]
Rectangular larval tank	2.9 m × 0.6 m	1.74	18.7	[3]
Incubation plate	0.65 m × 0.40 m	0.26	2.80	[3]

Planning note: Russian sturgeon larvae begin shifting to benthic feeding at about 8 dph, when exogenous feeding begins. At that point, tank bottom surface area becomes important for determining stocking density because the larvae increasingly occupy and feed along the tank bottom. The table below provides a practical range of stocking densities expressed as larvae/ft² and m² bottom area calculated using length × width only. These ranges were derived from multiple references that used different methods, including volumetric stocking rates, mean larval weights at different dph, and different water depths and tank shapes. Tanks used only for egg incubation or later juvenile grow-out were excluded.

Reference Notes

Larvae dph ranges are based on growth stages originating from multiple references; the 0.07–0.5 g, 0.6–1.0 g, 1.1–3.0 g, and 3.1–5.0 g rows were refined using interpolated growth points from FAO Table 37 and Memiş et al. (2009).
The “larvae at first feeding” row uses an interpolated weight of about 0.03–0.04 g from Memiş et al. (2009), based on 7 dph = 0.023 g and 14 dph = 0.055 g.
For the fry rows, interpolation from FAO Table 37 and Memiş et al. (2009) adjusts to about 36–56 dph for 1.1–3.0 g and about 57–75 dph for 3.1–5.0 g; reported other anchor points include 35 d = 1.0 g, 41 d = 1.18 g, 45 d = 2.5 g, and 75 d = 5.25 g.

Table 5. Practical Feeding Schedule for Russian Sturgeon Larvae Reared in RAS Tanks
Stage	Days post-hatch	Avg. length	Avg. weight	Main feed phase	Artemia /mL/feed	Feeds /day	Live-feed rate (% BW/day)	Microdiet rate (% BW/day)	Key notes
Yolk-sac (Prelarvae)	0–8	10 mm (day 1)	18 mg (day 1)	Endogenous / yolk-sac	0	0	0	0	No external feed; monitor for onset of exogenous feeding.
First feeding (Postlarvae)	8–11	18–23 mm	40–46 mg	Artemia nauplii	2–4	10	~60	0	Bottom/perimeter feeding; first practical live-feed stage.
Early transition	12–16	15 mm (day 14)	55 mg (day 14)	Artemia + minced tubifex	2–4	8	Artemia ~60; Tubifex ~30	0	Small, frequent portions; remove uneaten feed promptly.
Co-feeding	17–18	15–20 mm	55–95 mg	Live feed + microdiet	2–4	5	Live feeds continue	15	Bridge stage; artificial feed introduced while live feeds continue.
Weaning	19–32	20 mm (day 22)	95 mg (day 22)	Tubifex + microdiet	0	5	Tubifex ~30	10	Main transition period; digestion about 5–6 h in larvae.
Late weaning	33–41	55 mm (day 41)	1.18 g (day 41)	Commercial microdiet only	0	4	0	5	Metamorphosis complete; use sinking starter feed; grade if size diverges to avoid cannibalism.
On-growing	42–75	120 mm (day 75)	5.25 g (day 75)	Starter / sinking commercial diet	0	4	0	5	Increase pellet size gradually; maintain feed on tank bottom.

Abbreviations: BW = body weight. Length and weight benchmarks are anchor points from the source tables; intermediate values are practical stage markers for hatchery use.

Sources: Nathanailides et al., Hatching time and post-hatch growth in Russian sturgeon; Memiş et al. 2009, Turkish Journal of Fisheries and Aquatic Sciences 9:47–52.

References and Supporting Notes

Use note: Only sources relevant to Russian Sturgeon larvae were used for hatchery staging, larval tank design, or bottom-feeding strategies.

References
Resource Resource	Why it was included
[1] Chebanov, M.S., and E.V. Galich. 2013. Sturgeon Hatchery Manual. FAO Fisheries and Aquaculture Technical Paper 558.	Primary FAO hatchery reference: Timing first-feeding timing, bottom-feeding behavior, Russian sturgeon larval density baseline and other criteria
[2] Chebanov, M.; Rosenthal, H.; Gessner, J.; Van Anrooy, R.; Doukakis, P.; Pourkazemi, M.; Williot, P. 2011 Sturgeon hatchery practices and management for release-Guidelines. FAO Fisheries and Aquaculture Technical Paper No 570. FAO.	Supporting FAO production guidance paper 558 for hatchery management and release-oriented larval/fry handling. Used for Artemia feeding density of 2–4 Artemia/mL culture water and guidance to enrich live feeds.
[3] Memis, D., Ercan, M.S. Ceklikkale, M. Timur, and Z. Zarkua. 2009. Growth and Survival Rate of Russian Sturgeon Larvae from Fertilized Eggs to Artificial Feeding. Turkish Journal of Fisheries and Aquatic Sciences 9:47-52.	Core Russian sturgeon larval feeding schedule, tank dimensions, and stage-specific stocking rates.
[4] Nathanailides, C., M. Tsoumani, A. Papazoglou, and I. Paschos. 2002. Hatching Time and Post-hatch Growth in Russian Sturgeon Acipenser gueldenstaedtii. Journal of Applied Ichthyology 18:651-654.	Anchor source for early post-hatch growth timing. Cited widely in later Russian sturgeon hatchery studies.
[5] Kim, E.-J., et al. 2019. Behavioral Modifications in Response to Light Intensity in Russian Sturgeon Prelarvae. Fisheries and Aquatic Sciences 22:4.	Useful example of early prelarval behavior, phototaxis, and bottom/corner accumulation in hatchery tanks.
[6] Ak, K. 2023. Effects of Size Grading on Growth Performance, Survival Rate and Cannibalism in Russian Sturgeon Larvae. Aquatic Sciences and Engineering 38(1):47-52.	Recent Russian sturgeon larval culture paper used for current hatchery context and microdiet management protocol.
[7] Kamaszewski, M., T. et al. 2014. Effects of Artemia sp. enrichment with essential fatty acids on functional and morphological aspects of the digestive system in Acipenser gueldenstaedtii larvae. Turkish Journal of Fisheries and Aquatic Sciences 14:929–938. DOI: 10.4194/1303-2712-v14_4_12.	Discussion on impact feeding enriched Artemia to Russian sturgeon larvae. Feeding EFA-enriched Artemia had a beneficial effect on both the physiology and morphology of the digestive system.
[8] Conte, Fred S., et al. Hatchery Manual for the White Sturgeon (Acipenser transmontanus Richardson): With Application to Other North American Acipenseridae. University of California, Division of Agriculture and Natural Resources, Cooperative Extension, 1988. Publication 3322.	Excellent overall resource on numerous sturgeon species. Includes clear descriptions of larval development, need for live feeds and discussion on hatchery set-up.
[9] Kornienko V. O. and V. V. Olirfrenko, 2020. Dynamics of growing of Russian sturgeon (Acipenser gueldenstaedtii) larvae for different durations of cultivation. Regulatory Mechanisms in Biosystems 11(3), 438-443. Doi: 10.15421/022067	After 20 dph, larval size becomes more variable. Larger larvae begin to outcompete smaller individuals for feed. Cannibalism results, reducing survival. At this time, grading to separate larger from smaller larvae, and stocking each into different tanks, will improve survival and promote more uniform growth.

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