Analysis of the Microalgae Community in Industrial Aquaculture Ponds of Pacific White Shrimp (Litopenaeus vannamei)

Abstract:

The microalga community in 6 industrial aquaculture ponds of Pacific white shrimp (Litopenaeus vannamei) was analyzed at Baorong Aquatic Science and Technology Limited Corporation in Qingdao from June to September in 2015. The composition of species, abundance, biodiversity and characteristics of dominant species succession were investigated and discussed based on the situation of shrimp culture. A total of 49 species of microalgae were identified that belonged to 28 genera and 5 phylums (including 14 dominant species). The population density of microalgae was 5.2×105–9.4×108 cell/L, the biomass was 1.23–208.00 mg/L, and the biodiversity index was 0.42–2.44. The stability of the ecosystem was weak and the shrimps were prone to outbreaks of diseases when the biodiversity index was below 0.9. The dominant species in the early stage of cultivation were green algae, diatoms and some species of dinoflagellates. Microcystis incerta and Oscillatoria willei belonging to Cyanophyta gradually became the dominant species in the middle to late stages. The culture density of shrimp had significant effects on the succession of microalga dominant species. The shrimp grew well in a stable community of microalgae where the culture density was 300 ind/m2 (pond A1) and the dominant species were mainly green algae and diatoms. The harmful Oscillatorias tended to become the dominant species in the middle to late stages as the culture density was 400–500 ind/m2 (in pond B1, C1 and C2), which easily led to the outbreak of shrimp diseases. Our study provided important information on the tuning of the environment of industrial aquaculture ponds.