Search

Biological invasions of jellyfish may critically affect ecosystems and ecosystem services, yet their complex life cycle makes tracking their origins and dispersal vectors a challenging task. Here we combine citizen science observations, oceanographic modeling, and population genetics to track swarms of the invasive nomad jellyfish,Rhopilema nomadica, across the Eastern Mediterranean Sea. Jellyfish observations were recorded by citizens from two Israeli beaches in two consecutive years. A Lagrangian model coupled with a high-resolution 3D hydrodynamic model (SINMOD) was then used to simulate drift of ephyrae from probable polyp bed locations. Finally, mitochondrial DNA (mtDNA) sequence was constructed to examine swarm connectivity. Temporal (both seasonal and interannual) variation in observed swarms generally exceeded spatial differences between the two surveyed beaches. Early detection of swarms by citizens in offshore waters and the higher offshore particle distribution shown by the drift model, point to considerable offshore transport of the swarms. However, a higher probability was found for a nearshore location of the polyp beds, as nearshore origins were more closely correlated to hits on target beaches.R. nomadicareleased as ephyrae in early spring were likely to reach target beaches 200-300 km down current within two to three months as swarms of young adults in the early summer bathing season.R. nomadicapopulations exhibited little temporal or spatial genetic differentiation, a typical feature of a species that has recently undergone rapid population expansion. The offshore transport, the lack of genetic structure, and the interannual differences in both hydrodynamics and citizen scientist observations, all indicate decentralized swarm origins. This type of interdisciplinary approach can thus provide viable tools to track bloom formations. Understanding the complexity of jellyfish swarm dynamics supports future management strategies such as forecasting, preparedness and public education.

Aquaponics, the combined rearing of fish and hydroponic horticulture, has great potential for sustainable food production. Despite increasing research and investments in commercial scale systems, aquaponics is not yet a successful industry and most businesses report negative returns. Aquaponic produce is thought to contain added value to the consumer, and the environment. As most consumers are unaware of aquaponics and their benefits, little is known of its potential market. The present study addresses this gap by analysing willingness to consume aquaponic produce at different price levels in Israel and Australia. We used econometric tools to study the effects of pricing and other factors on revenues in each country. Cluster analysis was used to define groups of potential consumers. The results indicate that 17-30% of the population in both Israel and Australia would prefer to consume aquaponic produce once informed of their added value. Revenues at a given premium would be higher in Israel than in Australia, and higher for a leafy green, than for fish. Different segments of the population differed in their willingness to consume aquaponic produce, as well as in their stated motivations when purchasing food. Conclusions highlight the importance of case-specific research on consumer preferences and economic considerations preceding commercial investment in aquaponics.

Jellyfish (JF) swarms impact human wellbeing and marine ecosystems. Their global proliferation is a matter of concern and scientific debate, and the multitude of factors affecting (and affected by) their density and distribution merit long term monitoring of their populations. Here we present an eight-year time series for Rhopilema nomadica Galil 1990, the most prominent JF species swarming the Eastern Mediterranean Sea. Reports were submitted by the public and within it a group of trained participants via an internet website between June 2011 and June 2019. Data collected included species, size, location, ranked amount and stinging. Swarms of R. nomadica prevailed in July and ended in August but were also prominent in winter from January to March. Both observations deviate from past swarming patterns described in the late 1980s, when summer swarms persevered until October and winter swarms were not documented. Climate change (increasing water temperature) and the westwards up-current spread of R. nomadica are discussed as possible explanations for this phenological shift. We further demonstrate how data obtained by Citizen Science is used to develop a swarming indicator and monitor jellyfish in time and space, and propose a forecast based on these observations.

Microplastic distributions in a domestic wastewater treatmentplant: removal efficiency, seasonal variation and influence of sampling technique

Aquaponics, the combined rearing of fish and hydroponic horticulture, has great potential for sustainable food production. Despite increasing research and investments in commercial scale systems, aquaponics is not yet a successful industry and most businesses report negative returns. Aquaponic produce is thought to contain added value to the consumer, and the environment. As most consumers are unaware of aquaponics and their benefits, little is known of its potential market. The present study addressed this gap by analysing willingness to consume aquaponic produce at different price levels in Israel and Australia. We used econometric tools to study the effects of pricing and other factors on revenues in each country. Cluster analysis was used to define groups of potential consumers. The results indicate that 17-30% of the population would prefer to consume aquaponic produce once informed of their added value. Revenues at given premiums would be higher in Israel than in Australia, and higher for a leafy green, than for fish. Different segments of the population differed in their willingness to consume aquaponic produce, as well as in their stated motivations when purchasing food. Conclusions highlight the importance of case-specific research on consumer preferences and economic considerations preceding commercial investment in aquaponics.