Pond smelt Hypomesus olidus is a small-sized economic species of freshwater fish with delicious meat and high output. In this study, the complete mitochondrial genome of H. olidus sequenced to be 16,786 bp in length, including 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs and a control region. The overall base composition of H. olidus is 24.3% for A, 27.3% for T, 29.2% for C and 19.2% for G, with a slight A þ T bias. The mitogenome sequence data may provide useful information to the population genetics analysis of H. olidus and the elucidation of evolutionary mechanisms in Hypomesus fish.

The optimization of copepod feeding protocol is paramount to improve culture productivity and to maintain favorable water quality parameters overtime, as well as saving operational costs by preventing the production of unnecessary quantities of microalgae. The influence of microalgal feeding concentration on major parameters related to culture productivity of the calanoid copepod Bestiolina similis (Paracalanidae) was investigated in a series of laboratory experiments. B. similis was fed eight different concentrations (0, 150, 300, 600, 900, 1,200, 1,500 and 1,800 μgC l–1) of a mixed microalgal diet consisting of Tahitian strain of Isochrysis species, Pavalova 50 and Tetraselmis chuii at 1:1:1 carbon ratio. The results indicate that female daily and cumulative egg production over lifespan, egg hatching rate, naupliar and copepodite survival and development, adult female life expectancy, population growth and fecal pellet production rate (FPPR) were all significantly affected by microalgae feeding ration. Conversely, no significant influence could be established between microalgae food concentration and egg diameter or adult sex ratio. Feeding rations as low as 150 μgC l–1 led to lower egg hatching rates, survival and development, adult female life expectancy and population growth compared with the higher microalgae rations tested. Feeding concentration ≤ 900 μgC l–1 significantly limited female daily egg and fecal pellet production rate, as well as their cumulative egg production over lifespan, when compared to a level of 900 μgC l–1. Bestiolina similis fed with 1,200 μgC l–1 significantly improved female egg and fecal pellet production when compared to the lower treatments and was responsible for the highest female lifespan egg production and population growth observed among all treatments. Feeding rations as high as 1,500 μgC l–1 and 1,800 μgC l–1 did not lead to significant improvement in any of the parameters measured. This is likely due to a saturation effect at high food concentration which is known to decrease calanoid copepods feeding efficiency. Finally, B. similis FPPR, used as a proxy for ingestion, was found to saturate at a microalgae concentration of 783.4 μgC l–1 using a non-linear Michael-Menton (2 parameters), indicating that CVI female ingestion did not increase significantly above this concentration. Based on the above results it is recommended that B. similis cultures should be fed at a concentration of 1,200 μgC l–1, and not above, as rations > 1,200 μgC l–1 will not significantly improve any of the productivity-related parameters observed in this study. Feeding rations should never be below 783.40 μgC l–1 as this is the threshold level below which adult female ingestion rates become limiting.

The complete mitochondrial genome of Hemigrammus bleberi was obtained by the traditional polymerase chain reaction (PCR)-based sequencing approach. The mitogenome of H. bleberi was determined as 17 021bp in length, including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. Phylogenetic tree was constructed based on the complete mitogenomes of the species and closely related 21 teleost species to assess their phylogenetic relationship and evolution.

Myloplus rubripinnis and Metynnis hypsauchen are two compressed-bodied ornamental fishes of Serrasalmidae family. In this study, complete mitochondrial genome sequences of the two species were determined. The mitogenomes were 16662 bp and 16737 bp nucleotides in length, and both contained 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNA), 2 ribosomal RNAs (rRNA) and a control region. The phylogenetic tree revealed that Myloplus rubripinnis was closely related to Myleus sp. and Myleus cf. schomburgkii, while Metynnis hypsauchen was related to Pygocentrus nattereri, and then the two clades clustered into one group. Present mitogenome sequences of M. rubripinnis and M. hypsauchen will provide molecular information to the evolution and ecology studies of the two species.

The traditional polymerase chain reaction method was employed to obtain the complete mitochondrial genome of Andinoacara rivulatus from Lizigu farm, Tianjin city, China. The mitogenome was determined to be 16,585 bp in length. It contains 13 protein-coding genes, 2 rRNAs and 22 tRNAs. The sequence structure of non-coding control region was also analyzed. This is the first report on the complete mitogenome sequence of A. rivulatus.