Omnivorous Carp (Carassius gibelio) Increase Eutrophication in Part by Preventing Development of Large-Bodied Zooplankton and Submerged Macrophytes

Abstract

Fish, being an important consumer in aquatic ecosystems, plays a significant role by affecting the key processes of aquatic ecosystems. Omnivorous fish consume a variety of food both from pelagic and benthic habitats and may directly or indirectly affect the plankton community as well as the lake trophic state. We conducted a 72-day outdoor experiment in mesocosms with and without Prussian carp (Carassius auratus) to evaluate the effect of this often-stocked omnivorous fish on the plankton community and water quality. We found that the presence of fish increased the biomass of planktonic algae, total and inorganic suspended solids, leading to decreased light intensity in the water and a lower biomass of benthic algae. Fish also prevented development of submerged macrophytes and the establishment of large-bodied zooplankton. However, the fish did not increase nitrogen concentrations and even was lowered total phosphorus levels, in part due to nutrient storage in the fish. We conclude that stocking of Prussian carp should be avoided, or removed where stocked and abundant, to obtain good ecological quality of shallow lakes, characterized by clear water and high abundance of macrophytes.

Effects of Nile Tilapia (Oreochromis niloticus) on phytoplankton community structure and water quality: a short-term mesocosm study

“…Our study also showed that tilapia increased the concentration of TSS and decreased periphyton biomass. The increased concentration of TSS also contributes to deteriorating water quality (Hansson, 1992b;Vadeboncoeur and Carpenter, 2001;Zhang et al, 2015;Razlutskij et al, 2021). The decreased abundance of periphytic algae may further benefit phytoplankton growth, lowering the competition for sediment-associated nutrients (Hansson, 1990).…”

Comparison of the impact of native (Scardinius erythrophthalmus) and invasive (Carassius auratus gibelio) omnivorous fish on plankton and bethic algae communities, water quality and submerged macrophytes

“…In a study of Prussian carp (C. gibelio), Razlutskij et al (2021) found no increase in nutrient concentrations in the fish presence. In fact, TP was lower in the fish treatment than in the fish-free control.…”

“…Omnivorous fish tend to increase nutrient levels in water column, phytoplankton development and water turbidity and to decrease light intensity, which results in deteriorated conditions for submerged macrophytes and benthic algae, thereby intensifying the eutrophication (Tátrai et al 1997;Jeppesen et al 2003;Schallenberg and Sorrell 2009;Mei et al 2021;Pacheco et al 2021;Razlutskij et al 2021). For example, Prussian carp (Carassius gibelio) has been found to increase planktonic algal biomass, total suspended solids (TSS) and inorganic suspended solids (ISS) and to decrease light intensity (Richardson et al 1995;Mei et al 2021;Razlutskij et al 2021), while Crucian carp (Carassius auratus) has been found to increase turbidity, decrease benthic algae biomass and enhance release of nutrients from sediment to the water column, consequently promoting phytoplankton growth (Huang et al 2020).…”

Distribution and Expansion of Alien Fish Species in the Karun River Basin, Iran

“…The spread of tilapia can be controlled using biological methods, i.e., by supporting other organisms, ideally endemic and other native fish species. For example, predatory fishes such as the native Silurus triostegus and Leuciscus vorax have contributed to reductions in tilapia populations (especially juvenile tilapia) in the Khuzestan Province [97,106,107]. Management practices supporting their presence in the system would help address the issue.…”