For the past five years, our team has conducted RAS based larviculture research with Domesticated Striped Bass (DSB), Morone saxatilis, (distinct from both wild striped bass and hybrid striped bass). The principal goal was to develop tank-rearing techniques and methods to improve overall production during this early life stage through to metamorphosis (about 28 dph).
Striped Bass are physoclistous fish, requiring forcible inflation of the swim bladder (SBI) during early larval development, up to about 8 dph. Failure to successfully complete SBI results in skeletal deformities, poor growth and reduced survival (Fig 1). Feeding these larvae usually begins 4 dph-8dph after mouthparts form. A result of feeding, principally Artemia nauplii, is the release of uneaten oil that accumulates on the water surface as a thin surface-oil film. This oil film becomes a physical barrier impeding the ability of larvae to access surface air; a process required to complete SBI.
Our first efforts to assist SBI focused on published methods including: surface sprayers, fans, lipophilic pads, and absorptive clay particles, to name a few. All these methods failed. We then found a few early works on various air-driven surface skimmers and made modifications to fit our system. After much trial and error, we have developed a simple method and techniques that have resulted in 80-90% SBI success in post-larvae (Fig 2). Our experience and protocols will be discussed, the most important of which will be highlighted in this presentation.