The rearing environment is important for a stable production of good quality lobster juveniles. By providing an environment excluding pathogens and dominated by mutualistic bacteria, the probability of developing healthy host-microbe relationships and produce healthy juveniles is increased. Disinfection of water and sudden increase in the supply of organic matter in culture tanks are processes that open for uncontrolled microbial regrowth in the rearing water. This increase the variability in the development of the microbiota between replicate rearing tanks and promotes selection for potentially harmful opportunistic bacteria. In two start feeding experiments with European lobster (Homarus gammarus) we compared the bacterial environment in three types of rearing systems: a recirculating aquaculture system (RAS) with UV treatment directly in front of the rearing raceways, a RAS without disinfection, and a conventional flow through system (FTS). The RAS with no disinfection was hypothesised to stabilise the microbiota of the rearing water, select against opportunistic bacteria, and reduce variability in production outcome between replicate tanks compared to the other systems. As predicted, the three different systems developed significantly different compositions of the microbiota in the rearing water and the larvae. On average, the survival of larvae in RAS without disinfection increased with 43 and 275 %, in the first experiment, and 64 and 18 % in the second experiment, compared to RAS with UV and FTS, respectively. Also, the RAS without disinfection showed less variability in the survival of larvae between replicate tanks and batches compared to the other treatments. The results are promising for controlling the microbiota of the rearing water to improve, increase and stabilise the production of marine larvae by competent use of water treatment and selection regimes. Based on the presented and previous work, RAS is recommended over FTS, and in RAS it is recommended to avoid point-disinfection of the recirculating water, to provide a stable and beneficial microbial environment in the cultivation of marine larvae.

养殖环境对于稳定生产优质龙虾幼仔很重要。通过提供一个排除病原体并以共生细菌为主的环境，增加了发展健康的宿主-微生物关系并产生健康幼体的可能性。水的消毒和养殖池中有机物供应的突然增加是导致养殖水中不受控制的微生物再生长的过程。这增加了重复饲养池之间微生物群发展的可变性，并促进了对潜在有害机会性细菌的选择。在两次开始饲喂欧洲龙虾的实验中（Homarus gammarus) 我们比较了三种养殖系统中的细菌环境：在养殖水道前直接进行紫外线处理的循环水产养殖系统 (RAS)、未消毒的 RAS 和传统流通系统 (FTS)。假设没有消毒的 RAS 可以稳定养殖水的微生物群，选择对抗机会性细菌，并与其他系统相比减少重复池之间生产结果的变异性。正如预测的那样，三种不同的系统在养殖水中和幼虫中形成了显着不同的微生物群组成。平均而言，与使用紫外线和 FTS 的 RAS 相比，未经消毒的 RAS 中幼虫的存活率在第一个实验中分别增加了 43% 和 275%，在第二个实验中分别增加了 64% 和 18%。还，与其他处理相比，未经消毒的 RAS 在重复池和批次之间显示出幼虫存活率的较小变异性。结果有望通过适当使用水处理和选择制度来控制养殖水中的微生物群，以改善、增加和稳定海洋幼虫的产量。基于目前和以前的工作，RAS 被推荐而不是 FTS，在 RAS 中，建议避免循环水的点消毒，为海洋幼虫的培养提供稳定和有益的微生物环境。通过适当使用水处理和选择制度来增加和稳定海洋幼虫的产量。基于目前和以前的工作，RAS 被推荐而不是 FTS，在 RAS 中，建议避免循环水的点消毒，为海洋幼虫的培养提供稳定和有益的微生物环境。通过适当使用水处理和选择制度来增加和稳定海洋幼虫的产量。基于目前和以前的工作，RAS 被推荐而不是 FTS，在 RAS 中，建议避免循环水的点消毒，为海洋幼虫的培养提供稳定和有益的微生物环境。