RESUMO
Onychostoma ovale (Pellegrin & Chevey, 1936) is an endemic cyprinid fish that is widely inhabited in southern China, Vietnam, and Laos. In the present study, we first reported the complete mitochondrial genome of O. ovale. The mitogenome contained 16,600 bp with AT content of 56.2% and comprised of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region (D-loop). Phylogenetic analyses suggested that Onychostoma species formed two major clades and the subspecies of O. ovale had close relationship with O. rarum. The mitochondrial genome of O. ovale provided a key aid for population genetics and phylogenetic inferences of Onychostoma in future research.
RESUMO
The sharpbelly, Hemiculter leucisculus (Basilewsky, 1855) is a small cyprinid fish that has a wide distribution in East Asia. In this study, we characterized the complete mitochondrial genome of H. leucisculus in Hainan Island using Illumina MiSeq platform. The mitogenome contained 16,621 bp with AT content of 56.2%. The mitogenome of H. leucisculus comprised 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and one control region (D-loop). Phylogenetic analyses indicated that H. leucisculus in the Hainan Island formed independent lineage and the species of H. leucisculus might be a paraphyletic taxon.
RESUMO
Sarotherodon galilaeus (Linnaeus, 1758), a cichlid species that is naturally distributed in African and Eurasian waters, was introduced in many Asian countries for aquaculture. To date, rare genetic studies focused on this species have hindered our understanding of this species. Here, we reported the complete mitochondrial genome of S. galilaeus that was sequenced using next-generation sequencing technology. The resulting mitogenome of S. galilaeus was 16,630 in length and comprised 13 protein-coding genes (PCG), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA genes (rRNA), and one control region (D-loop). Phylogenetic analysis indicated that Oreochromini species contained two lineages (I and II) and S. galilaeus clustered with Oreochromis aureus rather than other Sarotherodon species.
RESUMO
Paranemachilus genilepis (Zhu 1983) is a small and benthic loach species that mainly distributes in the Guangxi Province, China. To date, little was known about the genetic information of this species as no molecular sequence has been published. In this study, the complete mitochondrial genome of P. genilepis was reported using the Illumina MiSeq platform. The genome was 16,563 base pairs (bp) in length and its structure was identical to most genomes of bony fishes. Phylogenetic analyses supported two clades (I and II) among Nemacheilidae species and P. genilepis was sister to Oreonectes furcocaudalis.
RESUMO
Low underwater light availability and benthivorous fish-mediated disturbance are two important factors that influence the growth of submersed macrophytes. However, the combined effects of these factors remain unclear. To determine the combined effects of low light and fish-mediated disturbance on the growth of two submersed macrophytes with contrasting growth forms, i.e., Vallisneria natans and Hydrilla verticillata, we conducted an outdoor mesocosm experiment with a two-by-two factorial design. The experiment involved two fish-mediated disturbance levels (0 and 1 Misgurnus anguillicaudatus) crossed with two levels of light intensity (ambient light and a low-light environment created by culturing the macrophytes under a shelter). The results showed that the chlorophyll a (chl a) concentration in the overlying water showed no difference among treatments for each macrophyte species. The fish-mediated disturbance significantly decreased the relative growth rate (RGR) of both species in the low-light environment but showed no effects in the ambient light environment. Low light availability and/or fish-mediated disturbance led to increased plant heights of both species compared with the heights under the ambient light regime. Low light availability combined with fish-mediated disturbance significantly reduced the ramet number and soluble carbohydrate (SC) content of both species; however, the free amino acid (FAA) content was not affected. Compared to V. natans, H. verticillata exhibited a high RGR and high ramet numbers in a low-light environment combined with fish-mediated disturbance. Our results indicated that the adaptability of H. verticillata is better than that of V. natans in turbid, shallow and hydrostatic water. Fish-mediated disturbance can negatively influence submersed macrophyte recovery in lakes when light is not abundant.
Assuntos
Clorofila A/análise , Peixes/fisiologia , Hydrocharitaceae/fisiologia , Animais , Lagos , Nitrogênio , Fósforo , Luz SolarRESUMO
In order to control cyanobacteria blooms with silver carp in Lake Taihu, an in situ experiment was carried out by stocking silver carp at a biomass of 35, 70, and 150 g m-3 and no carp control in waterproof enclosures. Physicochemical water parameters and biomass of plankton were measured in enclosures to evaluate the suitable stocking density of silver carp for relieving internal nutrients and constraining cyanobacteria growth in Lake Taihu. It is found that the 35 g m-3 silver carp group and 70 g m-3 silver carp group presented lower total phosphorus, lower chlorophyll-a, and higher water transparency. Increased nitrogen to phosphorus ratio, which indicated the result of algae decline in fish presence enclosures, was attributed to decline of phosphorus. Phosphorus decline also exerted limitation on reestablish of cyanobacteria bloom. Crustacean zooplankton biomass and Microcystis biomass decreased significantly in fish presence enclosures. Silver carp could be more effective to regulate algae bloom in enclosures with dense cyanobacteria. Therefore, nonclassic manipulation is supposed to be appropriate method to get rid of cyanobacteria blooms in Lake Taihu by stocking 35 to 70 g m-3 silver carp in application.
