Gammarus aequicauda (Аmphipoda) as a promising target for hypersaline aquaculture: New data and potential to serve as an aquafeed

Abstract

Gammarus aequicauda (Amphpoda) is one of the most promising gammarid species for hypersaline aquaculture. Its population was studied in a hypersaline lake located in Crimea with field sampling from 2019 to 2023, as well as in different laboratory experiments. Here, the COI fragments was sequenced in two color morphs (gray and pink), and two unique COI haplotypes independent of the morph were found. They belong to MOTU3 according to the classification of Hupalo et al., 2019, which is entirely consistent with this genetic group being distributed along the coasts of the Black and Azov Seas. The distribution of G. aequicauda in the lake has never been uniform; significantly higher concentrations were observed in the thickets of seagrass Ruppia, in the spring on average more than 5 times. The highest recorded abundance of this species in the lake was 89,200 m−3, and its total biomass then was 558 g m−3. In spring and summer, their numerical abundance in the Ruppia thickets was proportional to the density of Ruppia shoots and increased exponentially from March to July. The abundance of G. aequicauda observed in the lake even exceeded the values found in brackish and marine conditions. This species has three generations in Lake Moynaki during the growing season. It can be cultured at different salinities, including very successfully in 45 to 65 g L−1. It would be possible to obtain 5000 kg of its wet weight (approximately 710 kg of dry weight), per year from a hypersaline pond of 1 ha (0.01 km2).