CanGammarus aequicauda(Amphipoda) suppress a population ofBaeotendipes noctivagus(Chironomidae) in a hypersaline lake? A case of Lake Moynaki (Crimea)

Abstract

The ecosystems of hypersaline waters are characterized by the simplified trophic webs with the ‘loss’ of predators. In the absence of predators, their role can be effectively performed by omnivorous as Gammaridae species. In Lake Moynaki, a small hypersaline lake, Gammarus aequicauda is one of the most abundant animal species along with chironomid larvae Baeotendipes noctivagus. Both these species are promising objects to use in polyaquaculture, and this adds an importance to know their trophic relations. To analyse G. aequicauda feeding on B. noctivagus, the field and experimental studies were conducted in 2018 and 2019. In two habitats (Ruppia thickets and free water), the abundance of both species significantly differed, and in the thickets of Ruppia, the Gammarus abundance was higher, and of chironomid larvae was less. Taking into account our experimental results and chironomid larvae abundance in the lake during the study period (from 460 to 3,200 ind./m2), the authors conclude that larvae abundance did not limit the rate of their consumption in the lake by G. aequicauda, and one can consume up to 4 larvae per day. Thus, G. aequicauda could receive a diet of about 45% of their weight consuming about 2% of the available larvae daily in areas without the marine grass Ruppia thickets. In Ruppia thickets, chironomid larvae are not important food of G. aequicauda because the Ruppia leaves play a more important role in gammarid diet. With sufficient plant food resources, G. aequicauda can be successfully cultivated together with chironomid larvae.

The behavior of Gammarus aequicauda (crustacea, amphipoda) during predation on chironomid larvae: Sex differences and changes in precopulatory mate‐guarding state

“…Field research was done in Lake Moynaki (45°10′37″N, 33°18′ 50″E), one of the Crimean hypersaline lakes (Shadrin et al, 2019(Shadrin et al, , 2021. It is a small shallow marine lake separated from the Black Sea by an area of 1.8 km 2 , and has a depth from 0.45 to 1.00 m.…”

“…There are patches of the seagrass Ruppia maritima Linnaeus, 1753 in the lake. The abundance of gammarids and chironomid larvae was monitored in the open water and the Ruppia thickets for 2 years, and data on this were published (Shadrin et al, 2021).…”

“…Organisms acquire energy through food resources from the environment and allocate them to the fitness processes of survival, growth, and reproduction (Alimov et al, 2013;Prato et al, 2006;Shadrin et al, 2021;Winberg, 1960). Therefore, knowledge of the mechanisms and factors (concentration and kind of food, temperature, oxygen content, etc.)…”

“…The amphipod Gammarus aequicauda (Martynov, 1931) (Gammaridae) is an abundant widespread bento-plankton omnivorous species in the Mediterranean and Black Sea regions, inhabiting a wide salinity range (Evagelopoulos et al, 2008;Greze, 1977;Prato et al, 2006;Shadrin et al, 2019). In hypersaline water bodies, it is often the only species of amphipod and plays the key role of a predator that determines the species structure and abundance of planktonic and benthic invertebrates (Anufriieva & Shadrin, 2020;Evagelopoulos et al, 2008;Shadrin et al, 2019Shadrin et al, , 2020aShadrin et al, , 2020bShadrin et al, , 2021. This is also one of the key prey species for fishes and birds (Kevrekidis & Koukouras, 1989), and may serve as a promising object for aquaculture and ecotoxicology (Prato & Biandolino, 2005;Shadrin et al, 2020b).…”

“…This is also one of the key prey species for fishes and birds (Kevrekidis & Koukouras, 1989), and may serve as a promising object for aquaculture and ecotoxicology (Prato & Biandolino, 2005;Shadrin et al, 2020b). In a previous study, it was shown that males of G. aequicauda actively eat chironomid larvae (Baeotendipes noctivagus (Kieffer, 1911)), and can negatively affect their abundance in nature (Shadrin et al, 2021).…”