Morphological parameters of Siberian shrimp larvae Exopalaemon modestus (Heller) in warm- water aquaculture

Freshwater shrimp species with a shortened larva development period are suitable for acclimatization into cooling ponds of energy facilities, both to enrich their food base and for cultivation. Siberian shrimp Exopalaemon modestus (Heller) are characterized by a wide range of ecological plasticity and a high survival rate of larvae with two zoea stages, making them a promising object for this purpose. In this regard, the anatomo-morphological indices, body structure, size characterization of zoea stages 1 and 2, as well as the postlarvae stage, when reared on discharged heated water of a thermal power plant, are described in detail. The larvae were reared in production conditions of the hatchery in aquaria equipped with drainage devices, where water was continuously supplied from the warm channel of Berezovskaya Thermal Power Station (TPS) (Brest region, Belarus) at a temperature of 20–22 ℃ and an initial planting density of 10 eggs/liter. In these conditions, the mean duration of larval development was 7 days, which is 1 day longer than during rearing in laboratory conditions in brackish water (3.12–4.03 ‰) and at temperatures of 26–28 ℃. In this regard, anatomo-morphological parameters, body structure, and size characteristics of the 1 st and 2 nd stages of zoea and postlarvae stages during rearing on the discharge heated water of the thermal power plant are described in detail. The average length of larvae of the first zoea stage was 4.08 ± 0.12 mm, of the second stage was 4.47 ± 0.23 mm, and of the postlarvae stage was 4.70 ± 0.26 mm. On average, the inter-larval period for the 1 st and 2 nd zoea stages lasted two days, while the postlarvae stage, it averaged at three days. The general identifying characteristics for these stages of ontogenesis were: the structure of the eyes, antennules, pereopods, pleopods, rostrum, and carapax. The original drawings and lengths of rostrum, eyes, carapax, antennae, antennules, mandibles, maxillae, maxillapedes, pereopods, pleopods, and telson are provided.