Management of nauplius production in the paracalanid, Bestiolina similis (Crustacea: Copepoda): Effects of stocking densities and culture dilution

Bestiolina similis cultures were managed to increase nauplius production. Higher nauplius production was achieved by increasing the initial stocking densities of adults and sub-adults (C5–C6). However, these periods of high nauplius production were short compared to cultures stocked at lower C5–C6 densities. Female fecundity was inversely related to stocking densities and with the age of the culture. Populations of B. similis were periodically diluted by either reseeding or upscaling of the experimental cultures. Following dilution, population densities remained constant for 1 to 8 days and then increased linearly at rates ranging from 270 to over 600 ind L− 1D− 1. In these cultures, female fecundity declined from 28 to 11 eggs per female per day. Timing of the culture dilution is important. Cultures, diluted during the period of population increase, had higher rates of increase and reached higher densities than the late-diluted cultures. Enrichment of diluted cultures with copepodites (C5–C6) shortened the delay and produced higher rates of population increase and maximum densities. Management of the population through dilution of cultures and manipulation of adult stocking densities improved nauplius production in the cultures. Increasing and predicting nauplius production are two primary steps towards the use of copepod nauplii as first feeds.