Ecologia populacional da medusa exótica Cassiopea andromeda Forskâl, 1775 (Cnidaria: Scyphozoa) em uma fazenda de camarão e em um ambiente de manguezal no Nordeste do Brasil

Abstract

The phenomena of jellyfish blooms are increasing and these have been explained by environmental drivers such as eutrophication, climate change, overfishing, the spread of artificial marine substrates and the introduction of invasive species. Currently five jellyfish species are considered invasive , and one of them is from the genus Cassiopea, known as "the upside-down jellyfish". A unique feature of this jellyfish is their symbiosis with the dinoflagellate Symbiodinium spp; a coral-like nutritional strategy. This dissertation is divided in 2 chapters, in which the general objective of this dissertation will be to analyze the population ecology of the Cassiopea jellyfish in mangroves and shrimp farms . The work was carried out in the months of July/18, October/18, January/19 and April/19 in two environments: shrimp farm (municipality of Acaraú) and mangroves (municipality of Itarema) in the Equatorial Atlantic (Ceará, Brazil). In chapter one, Cassiopea sp. was identified by molecular analysis. The exotic species identified was C. andromeda which is native to the Red Sea. Furthermore, we showed the first record of C. andromeda in aquaculture activities worldwide and discussed the effects of this invasion since the species presents only females in the population that must be reproducing asexually with low genetic variability. Chapter two focused on population structure and environmental parameters (temperature, pH, salinity, chlorophyll a, nitrogen and total phosphorus) that may be interfering with the success of the jellyfish invasion in both environments. The environmental factors had differences from one environment to the other, in which a major component analysis (PCA) and cluster analysis was applied for the understanding of spatial and temporal patterns. In shrimp farms, exotic jellyfish were present during all months of study and were larger compared to the population in the mangrove swamp, which had more limitations to its survival and biomass. In carciniculture, the exotic jellyfish presented the largest sizes ever recorded worldwide, which indicates that anthropic activity helps in the success of the invasion. Thus, this dissertation provides unpublished information of ecological and economic importance for the management of this invasion phenomenon.