Abstract

In the present study, the most appropriate feeding regimes for the prevalent sole (Solea solea) larvae during the early larval rearing staged (first month) were investigated. Two experiments were conducted to improve the growth performance [the ultimate Body Weight (FBW), Specific Growth Rate (SGR), and Weight Gain (WG)] and survival rate of S. solea larvae. For each experiment, larvae were fed with alive rotifers and Artemia from the third and fifth Day After Hatching (DAH), respectively till the 30th DAH. In the first experiment, three feeding trials (10, 20, and 30 rotifers ml⁻¹) were conducted (in triplicate for each treatment) to set the best rotifer densities as the first feed for S. solea larvae. In the second experiment, larvae were fed with Artemia at the 5th (group Ӏ), 10th (group ӀӀ), or 15th (group ӀӀӀ) DAH (in triplicate for each treatment) to optimize the suitable timing for Artemia introduction to larval rearing tanks. The first experiment indicated that growth performance was enhanced by increasing the density of rotifers in the larval trials; larvae fed with 30 rotifers ml⁻¹ showed the highest values for FBW (9.89±1.07mg), WG (8.89±1.07mg), and SGR% day⁻¹ (8.44%±0.39%). Furthermore, standard length and survival rate increased significantly (p < 0.05) as rotifer density was increased to 30 rotifers ml⁻¹, reaching 9.05 ±0.30mm and 85.99%±3.62%, respectively. The second experiment revealed that early introduction of Artemia at the 5th DAH in larval tanks led to a significant (p<0.05) rise in FBW, WG, and SGR% day⁻¹ in S. solea larvae (10.18±0.88mg, 9.18±0.87mg, and 8.57%±0.33%, respectively). Additionally, the survival rate of larvae was improved slightly in group Ӏ compared with the survival rates in groups ӀӀ and ӀӀӀ. Findings of this work concluded that feeding a high density of rotifers to S. solea larvae significantly increased the survival rate, standard length, and width of the larvae. Additionally, introducing Artemia in the early stage after hatching rather than later significantly increased S. solea larval growth rate, survival, stander length, and width.

Keywords: Rotifer; Artemia; Solea solea; Live food; Fish larvae

Abbreviations: SGR: Specific Growth Rate; WG: Weight Gain; DAH: Day After Hatching; FBW: Final Body Weight; SL: Standard Length; NIOF: National Institute of Oceanography and Fisheries; DO: Dissolved Oxygen