This review examines the initial swimbladder inflation in cultured finfish larvae and the mechanisms controlling body buoyancy and the distribution of larvae during the critical early development stages. The literature suggests that the body buoyancy of larvae affects their distribution in the tank and fish with low buoyancy are likely to sink to the bottom leading to mortality. Initial swimbladder inflation occurs in a finite period of the postlarval stage and a number of biotic and abiotic factors have been associated with preventing inflation during the ‘window’ period. In recent times larval rearing techniques have been advanced, but it is still a challenge to increase the initial swimbladder inflation rates and maintain larval positioning in the water column to reduce mortality. This review shows that various nutritional and abiotic factors can be manipulated in the culture of many finfish species to achieve high rates of swimbladder inflation and reduce deformations and mortality during early larval rearing.

ÔØ Å ÒÙ× Ö ÔØThis is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 AbstractMortality is a major concern in larval fish rearing during exogenous feeding. An important cause of mortality of larval yellowtail kingfish (Seriola lalandi) during the rotifer -Artemia weaning period was hypothesized as being due to larval sinking response after satiated feeding prior to dusk. This paper documents the effect of larval body density change under different Artemia feeding regimes and adds to the understanding of the cause of mortality of yellowtail kingfish larvae. The change in body density was used as a tool to determine the time of last feed in a day to ensure larvae were neutrally buoyant at dusk. An adaptive Artemia feeding regime was implemented, in which the amount of feed applied to the larvae was modified based on the body density. Larvae were denser than the seawater in which they were reared when fully satiated with Artemia. The time required to return to pre-feeding density significantly decreased with larval age. At 12 days post hatch (dph), the peak in body density of larvae fed Artemia to satiation was 1.0320 g cm -3 and they did not return to a prefeeding body density (1.0260 g cm -3 , for approximately 10 h. By 19 dph, larval body density only increased to 1.0275 g cm -3 when larvae were fully satiated and they were neutrally buoyant again by 4 h. The decrease in larval body density when fully satiated at 16 dph demonstrated that overfeeding larvae with Artemia should be avoided prior to dusk before this age to maintain neutral buoyancy. The use of the adaptive regime reduced mortality by 20% compared with the control, from 13 to 17 dph, without sacrificing larval growth.Transition to Artemia feeding is a critical stage for yellowtail kingfish larvae and mortalities can be significantly reduced during this period by managing the timing of Artemia feeds throughout the day. The strategy of an adaptive feeding method may be considered a novel management tool to prevent larval sinking and associated mortality during the period of weaning from rotifers to Artemia during larval rearing.

Poor swimbladder inflation leads to low fish survival due to resulting spinal deformities and the inability to feed and develop normally. Failure of swimbladder inflation may be attributed to the inappropriate range of abiotic conditions. This study investigated the effects of temperature, light source and intensity, and oxygen conditions on initial swimbladder inflation, growth and survival of yellowtail kingfish Seriola lalandi larvae. The study consisted of four separate trials including low (21.5°C) and high (24.5°C) temperatures, natural and artificial light sources, low (1000 lux) and high (32 000 lux) light intensities, and ambient and supersaturated dissolved oxygen. Initial swimbladder inflation was only significantly affected by light source, with the highest inflation rate (97.5 ± 3.5%) under artificial light. Fish growth was improved at the higher temperature and at the higher light intensity. Survival was only significantly influenced by light intensity, with the highest survival (11.0 ± 2.3%) at the high intensity (32 000 lux). This study indicates that light source affects swimbladder inflation timing and high artificial light intensity improves larval fish growth and survival.

Bioavailability and palatability of praziquantel incorporated into solid-lipid nanoparticles fed to yellowtail kingfish Seriola lalandi.

First feeding success is critical to larval marine finfish and optimization of live feed densities is important for larval performance and the economics of commercial hatchery production. This study investigated various rotifer feeding regimes on the prey consumption, growth and survival of yellowtail kingfish Seriola lalandi larvae over the first 12 days post hatch (dph). The common practice of maintaining high densities of rotifers (10-30 ind. mL À1 ) in the rearing tank was compared to a low density feeding technique, where 5-8 ind. mL À1 of rotifers were offered. A 'hybrid' feeding regime offered rotifers at the high density treatment until 5 dph and the lower feeding densities thereafter. There was no significant difference in larval survival (hybrid: 28.9 AE 7%, low density: 17.3 AE 5% and high density: 17.2 AE 9%) or growth (hybrid: 6.12 AE 0.18 mm, low density: 6.03 AE 0.10 mm and high density: 6.11 AE 0.23 mm) between treatments. Rotifer ingestion was independent of rotifer density throughout the trial and increased with larval age, with larvae at 4 dph ingesting 22 AE 1.5 rotifers larvae À1 h À1 and by 11 dph ingesting 59 AE 1.6 rotifers larvae À1 h À1 . These data demonstrate that from first feeding, yellowtail kingfish larvae are efficient at capturing prey at the densities presented here and consequently significant savings in rotifer production costs as well as other potential benefits such as facilitation of early weaning and improved rotifer nutritional value may be obtained by utilizing lower density rotifer feeding regimes.