No abstract

The rapid, global spread of COVID-19, and the measures intended to limit or slow its propagation, are having major impacts on diverse sectors of society. Notably, these impacts are occurring in the context of other anthropogenic-driven threats including global climate change. Both anthropogenic stressors and the COVID-19 pandemic represent significant economic challenges to aquaculture systems across the globe, threatening the supply chain of one of the most important sources of animal protein, with potential disproportionate impacts on vulnerable communities. A web survey was conducted in 47 countries in the midst of the COVID-19 pandemic to assess how aquaculture activities have been affected by the pandemic, and to explore how these impacts compare to those from climate change. A positive correlation between the effects of the two categories of drivers was detected, but analysis suggests that the pandemic and the anthropogenic stressors affect different parts of the supply chain. The immediate measurable reported losses varied with aquaculture typology (land vs. marine, and intensive vs. extensive). A comparably lower impact on farmers reporting the use of integrated multitrophic aquaculture (IMTA) methods suggests that IMTA might enhance resilience to multiple stressors by providing different market options under the COVID-19 pandemic. Results emphasize the importance of assessing detrimental effects of COVID-19 under a multiple stressor lens, focusing on areas that have already locally experienced economic loss due to anthropogenic stressors in the last decade. Holistic policies that simultaneously address other ongoing anthropogenic stressors, rather than focusing solely on the acute impacts of COVID-19, are needed to maximize the long-term resilience of the aquaculture sector.

An experimental recirculating aquaculture system was constructed under ambient seawater conditions to compare microbial community diversity of nitrifying and denitrifying biofilters that were derived from a commercial inoculum used for aquarium applications. Next generation sequencing revealed distinct and diverse microbial communities in samples analyzed from the commercial inoculant and the denitrification and nitrification biofilters. In all samples, communities were represented by a few dominant operational taxonomic units (OTUs). Bacteria having the capacity to carry out ammonia and nitrite oxidation were more abundant in the nitrification biofilter. Similarly, the proportion of the bacterial taxa known to carry out heterotrophic and autotrophic denitrification and participate in sulfur cycling were found in the denitrification bioreactor, and likely originated from the ambient environmental water source. Our results indicated that environmental seawater can be a favorable enhancement to the bacterial consortium of recirculating aquaculture systems biofilters.

No abstract

The Croatian part of the Adriatic Sea covers more than 35% of the total Croatian territory, which means that monitoring changes in marine ecosystems and the conservation of biodiversity are of great importance. Following global changes, Croatia is experiencing increasing problems due to the introduction of new species that include aliens (due to aquaculture activities and shipping) and species from other Mediterranean subregions that are extending their geographic range. This work provides a checklist of introduced species in Croatian waters. A total of 113 species (15 phytoplankton, 16 zooplankton, 16 macroalgae, 44 zoobenthic and 22 fish species) have been recorded in the eastern part of the Adriatic Sea, of which 61 species are alien and 52 introduced, due to climate change.