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In an aquaponic system, fish and plants are cultivated together in a symbiotic environment where they mutually benefit, using significantly less water than traditional farming methods. The main aim of this study was to investigate the occurrence of antimicrobial resistance in two aquaponic systems implemented in two Chilean high schools using rainbow trout and lettuce cultures. When water samples (fish tank, biofilter, and plant raft) were analyzed over a three-month period, no resistance to oxytetracycline was detected, whereas the occurrence of resistance to florfenicol was rather small, ranging from 0.01% to 3.1% of bacterial culturable counts. Eighteen isolates were recovered from various sources as representatives of the florfenicol-resistant population, and all of them belonged to the Pseudomonas genus, showing a multi-drug-resistance phenotype and exhibiting simultaneous resistance to 7–13 antimicrobials. All isolates exhibited resistance to amoxicillin, chloramphenicol, florfenicol, and furazolidone and susceptibility to meropenem, oxytetracycline, oxolinic acid, flumequine, ciprofloxacin, and enrofloxacin. Five and two isolates carried the amphenicol-resistance-encoding genes floR and cmlA, respectively, whereas no carriage of integrons or the fexA, fexB, pexA, optrA, and cfr genes encoding for florfenicol resistance was detected. Eleven isolates carried plasmids, but only two of them were able to transfer their plasmid content by conjugation. The knowledge of the microbiome associated with aquaponic systems is still scarce, and their role as potential reservoirs of antimicrobial-resistant bacteria and related genes of these systems must be elucidated. [ABSTRACT FROM AUTHOR]

In contrast to freshwater aquaculture and the culture of anadromous species such as salmon, marine fish culture is in its infancy. The small larval size of many marine species presents significant challenges to culture, however, these highly valuable fish offer considerable promise for aquaculture. A particularly attractive group for marine aquaculture is the flatfish. The California halibut, Paralichthys californicus, with a range in nature from Washington State south to Baja California Sur, Mexico is one such species. With the goal of enhancing the fishery for this species, a hatchery program was developed over a decade ago. The hatchery at Redondo Beach, California, maintains a group of adults that routinely spawn throughout most of each year. Further development of routine culture and juvenile growout techniques ultimately aimed at commercial aquaculture was initiated last year with support from the California Sea Grant College Program. Profitable commercial ventures culturing various flatfish species already exist in other parts of the world, but development of a flatfish culture industry in California confronts unique challenges. Two challenges in particular are the relatively high cost of energy and stringent environmental regulations. To meet these challenges, a culture system built around recirculation technology is being developed that would allow for an energy- efficient industrial-like approach to the culture of California halibut while minimizing environmental impacts. [ABSTRACT FROM PUBLISHER]