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Fish larvae suffer high starvation mortality during the transition from yolk absorption to exogenous feeding, and the size of the developing buccal structures limits the food they can consume. Determining the suitable timing and size of live or inert foods could decrease this mortality. We described mouth development and determined the yolk absorption rate and point-of-no-return (PNR) of Dormitator latifrons larvae. One male and one female specimen were induced to spawn using salmon GnRHa implants, and 45 of their larvae were sedated and observed under a microscope every 24 h to measure total length, standard length, yolk sac length, yolk sac width, oil globule length, oil globule width, width of the oesophagus, and length of the upper and lower jaw longitudinal. The growth model, maximum mouth opening, daily survival, and starvation period were determined. The larval growth was fastest during the first 24 h post−hatching (HPH) at 28 ± 1 °C with an average increase of 625.42 µm in total length and 573.51 µm in standard length. The highest percentage of yolk absorption (52%) occurred within 24 HPH and at 96 HPH the yolk sac was completely reabsorbed. The PNR was reached at 156.41 HPH (p < 0.05). At 96 HPH, the upper and lower jaw were distinguishable by mouth movements. Our results suggest that the larvae of D. latifrons should be fed at 96 HPH with prey measuring 50–65 µm. [ABSTRACT FROM AUTHOR]

Objective. To evidence of the presence of two species of monogeneans of the genus Cichlidogyrus that cause damage to gill tissue, in tilapia Oreochromis spp. grown in Ecuador. Materials and methods. The gills were placed in a Petri dish with boiling water so that the parasites relax, and later they were fixed in 4% formalin. The samples were checked under a stereoscope microscope. The parasites were counted and preserved in 70% ethanol for their taxonomic identification according to their morphological characteristics. The infection parameters (prevalence, mean abundance and mean intensity) were calculated for each species of parasite. For the description of histological damages, fragments of parasitized gills were fixed in 10% neutral formalin and processed by the histological paraffin embedding technique. Results. Cichlidogyrus sclerosus showed highest infection parameters, prevalence of 65%, mean abundance of 24.24 ± 68.62 and mean intensity of 37.62 ± 82.93. Cychlidogyrus dossoui was observed in a prevalence of 4.5%, mean abundance of 0.13 ± 0.66 and mean intensity of 3 ± 1.41. Both species caused hyperplasia in lamellae. Conclusions. This study constitutes the first report of infestation by Cichlidogyrus sclerosus and C. dossoui in tilapia culture systems of Ecuador. [ABSTRACT FROM AUTHOR]