Selection of suitable aquaponics system for empurau (Tor tambroides) fries nursery in polyculture method

Long-term use of the recirculated water for fish and crop production in the aquaponics system that is the major concern in sustainable aquaculture for reduction of the water quality led to explore the alternative way of short-time use of recirculated water in the aquaponics system that can be in nursery management. Three individual aquaponics (nutrient film “NFT,” deep water “DWC,” media bed “MBD”) along with a new combined aquaponics system (CAS) were used to explore the most suitable aquaponics system for empurau fries nursery. It was done by determining the comparison of growth performance and survivability of fish fries and plants along with the cost–benefit analysis among 4 aquaponics systems. The study was conducted in two phases. Phase 1 comprised of determining the effectiveness test of filters in newly designed CAS and the selection of suitable plant for the second phase. The suitability test for the selection of an aquaponics system for empurau fries nursery was done in the second phase. The polyculture method was adopted in both phases. The newly designed CAS with filter and the leafy vegetables (Apium graveolens var. secalinum) were selected from the first phase for further study in phase 2. The suitability results in the second phase exhibited that the NFT aquaponics system was significantly (P DWC ≥ CAS > MDB. Therefore, the study suggests using the NFT aquaponics system for empurau (Tor tambroides) fries’ nursery in short term

Master recyclers: features and functions of bacteria associated with phytoplankton blooms

Marine phytoplankton blooms are annual spring events that sustain active and diverse bloom-associated bacterial populations. Blooms vary considerably in terms of eukaryotic species composition and environmental conditions, but a limited number of heterotrophic bacterial lineages — primarily members of the Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria — dominate these communities. In this Review, we discuss the central role that these bacteria have in transforming phytoplankton-derived organic matter and thus in biogeochemical nutrient cycling. On the basis of selected field and laboratory-based studies of flavobacteria and roseobacters, distinct metabolic strategies are emerging for these archetypal phytoplankton-associated taxa, which provide insights into the underlying mechanisms that dictate their behaviours during blooms

Recent advances of marine ornamental fish larviculture: broodstock reproduction, live prey and feeding regimes, and comparison between demersal and pelagic spawners

Marine ornamental fish are a key component of the multimillion‐dollar marine aquarium trade industry, a controversial industry due to current heavy reliance on wild‐collected specimens. Aquaculture of marine ornamental fish is considered as a sustainable alternative, but it is still in the early stage of development. This review focuses on the current state of marine ornamental fish aquaculture, by covering topics on reef fish reproductive biology in captivity, traditional and novel live feeds, feeding regimes and visual environment in larviculture. Where possible, major differences between demersal and pelagic spawners are compared and discussed. Overall, for many ornamental fish species, natural spawning can be achieved in a captive environment without the use of hormone induction; however, sex identification and successful pairing for reef fish species could be a challenge. With the use of both traditional (rotifers and Artemia) and novel live feeds (e.g. marine copepods and ciliates), a range of breakthroughs in larval rearing of both demersal and pelagic spawning ornamental fish species have been achieved in recent years, although larval survival varies. To further improve the larval rearing success of marine ornamental fish, this review suggests that future research should focus on optimizing the use of live feed in terms of both quality and quantity, and establishment of well‐defined species‐specific larval feeding regime, as well as providing appropriate rearing condition through improved manipulation of light conditions and the 'greenwater' techniques in larval rearing