Effect of size grading on growth of yellow Pacific shortfin eel (Anguilla bicolor pacifica)

Abstract

Heterogeneous growth, which is common among farmed fish, can be remedied by size grading. This study focused on whether the size grading process, which is commonly practiced in aquaculture, improves the subsequent growth performance of the Pacific shortfin eel Anguilla bicolor pacifica. Eels [338.70 ± 4.70 mm total length (TL) and 84.93 ± 1.87 g body weight (BW)] were initially reared for 60 days (pre-size grading period) and manually divided into three size groups: small (≤115 g), large (>150 g) and mixed (>115 g but <170 g), all maintained at a density of 5 kg m À3 and reared until day 150 (size grading period). After size grading, mean BW and TL at harvest significantly differed in all eel groups, suggesting growth was size specific. Nonetheless, at day 150, except for biomass, size grading had no significant effect on growth and survival, coefficient of variation of length and weight, and Fulton's condition factor. Large eels had a significantly higher feed intake than mixed or small eels, whereas feed efficiency did not differ among eel groups. Results suggest that size grading promotes size-specific growth but did not improve the overall growth performance of yellow stage of A. bicolor pacifica.

Alternate Day Feeding as a Cost-effective Strategy for Tank Culture of the Pacific Shortfin Eel Anguilla bicolor pacifica

“…This study examined the effects of daily (DF) and alternate day feeding (ADF) strategies on growth performance, feed utilization, body composition, blood chemistry, liver and intestinal morphology, and economic viability of Pacific shortfin eel (A. bicolor pacifica). Information from this study is relevant to the efforts of Aya and Garcia (2022) and Aya et al (2023) to develop an appropriate feed management strategy leading to compensatory growth for efficient culture of this tropical eel species.…”