Muggiaea atlantica

About: Muggiaea atlantica is a research topic. Over the lifetime, 77 publications have been published within this topic receiving 2688 citations.

Anthropogenic causes of jellyfish blooms and their direct consequences for humans: a review

Abstract: Although recent articles state that jellyfish populations are increasing, most available evidence shows that jellyfish abundances fluctuate with climatic cycles. Reports of increasing prob- lems with jellyfish, especially in East Asia, are too recent to exclude decadal climate cycles. Jellyfish are infamous for their direct negative effects on human enterprise; specifically, they interfere with tourism by stinging swimmers, fishing by clogging nets, aquaculture by killing fish in net-pens and power plants by clogging cooling-water intake screens. They also have indirect effects on fisheries by feeding on zooplankton and ichthyoplankton, and, therefore, are predators and potential competitors of fish. Ironically, many human activities may contribute to increases in jellyfish populations in coastal waters. Increased jellyfish and ctenophore populations often are associated with warming caused by climate changes and possibly power plant thermal effluents. Jellyfish may benefit from eutrophication, which can increase small-zooplankton abundance, turbidity and hypoxia, all conditions that may favor jellyfish over fish. Fishing activities can remove predators of jellyfish and zooplanktivorous fish com- petitors as well as cause large-scale ecosystem changes that improve conditions for jellyfish. Aquacul- ture releases millions of jellyfish into Asian coastal waters yearly to enhance the jellyfish fishery. Aquaculture and other marine structures provide favorable habitat for the benthic stages of jellyfish. Changes in the hydrological regime due to dams and other construction can change the salinity to favor jellyfish. Accidental introductions of non-native gelatinous species into disturbed ecosystems have led to blooms with serious consequences. In many coastal areas, most of these environmental changes occur simultaneously. We summarize cases of problem jellyfish blooms and the evidence for anthropogenic habitat disruptions that may have caused them. Rapid development in East Asia makes that region especially vulnerable to escalating problems. We conclude that human effects on coastal environments are certain to increase, and jellyfish blooms may increase as a consequence.

Fauna of the Mediterranean Hydrozoa

Abstract: This study provides a systematic account of the hydrozoan species collected up to now in the Mediterranean Sea. All species are described, illustrated and information on morphology and distribution is given for all of them. This work is the most complete fauna of hydrozoans made in the Mediterranean. The fauna includes planktonic hydromedusae, benthic polyps stages and the siphonophores. The Hydrozoa are taken as an example of inconspicuous taxa whose knowledge has greatly progressed in the last decades due to the scientific research of some specialists in the Mediterranean area. The number of species recorded in the Mediterranean almost doubled in the last thirty years and the number of new records is still increasing. The 457 species recorded in this study represents the 12% of the world known species. The fauna is completed with classification keys and a glossary of terms with the main purpose of facilitating the identification of all Meditrranean hydrozoan species

Dietary composition and diel feeding patterns of epipelagic siphonophores

Abstract: Prey consumption patterns are described for 24 species of epipelagic siphonophores studied during 1977–1980 in the Gulf of California, off Southern California, in the Sargasso Sea, and in Friday Harbor, Washington. Of the species, 7 were studied by day and at night, 15 were studied only by day, and 2 were studied only at night. Each of the 3 suborders of siphonophores had a characteristic diet. Siphonophores in the suborder Cystonectae, which had large gastrozooids, fed primarily on fish larvae. Species in the suborder Physonectae, which generally had few, large gastrozooids, consumed some small copepods, but consumed mainly large copepods and a variety of large, noncopepod prey. Species in the suborder Calycophorae, which generally had many small gastrozooids, fed mainly on small copepods, and also on other small prey organisms. The maximum size of prey tended to be correlated with gastrozooid length for all the siphonophores studied. For a given siphonophore species, the number of ingested prey was greatest at localities where prey organisms were most abundant in the surrounding seawater. For siphonophore species collected both day and night, there was a tendency for more prey to be consumed at night. Behavioral observations in the laboratory indicated that of 7 siphonophore species tested, 2 fed only in the light, and another fed only in the dark.

Zooplankton and ichthyoplankton communities in a temperate estuary: spatial and temporal patterns

Abstract: Zooplankton and ichthyoplankton assemblages were studied from January 2003 to June 2004 in a temperate shallow estuary (Mondego estuary, Portugal). Monthly sampling was performed at five stations at high and low tides, with subsurface tows with 335 and 500 μm mesh Bongo nets. Analysis of variance (ANOVA) showed a significant effect (P < 0.05) of the mesh size of the net on the abundance of main zooplankton groups. On average, the abundance of the 500 μm taxocenosis was 67 and 102 times lower than the 335 μm taxocenosis at high and low tides respectively, especially in the south arm. More than 80 species were identified in the zooplankton samples. The upper reaches of northern arm are dominated by freshwater crustacean mesozooplankton like Acanthocyclops robustus and Diaptomus spp. and the cladocerans Daphnia, Ceriodaphnia and Bosmina, often being codominant. In the southern arm, the resident estuarine copepod Acartia tonsa was dominant, eventually being the most abundant taxon. Marine reaches of estuary are usually dominated by the marine calanoid copepods Acartia clausi and Temora longicornis and the siphonophores Muggiaea atlantica. Concerning the ichthyoplankton, this was dominated by the larvae of estuarine resident species, mainly Pomatoschistus sp., and eggs of Engraulis encrasicolus. The abundance of Pomatoschistus sp. larvae was positively correlated with water temperature. Statistical analysis (canonical correspondence analysis) used to determine the spatiotemporal structure of the zooplankton assemblages and its correlation with environmental variables showed that salinity and temperature were the main factors influencing the distribution of zooplankton. The results obtained also showed that abundance was strongly influenced by the hydrological circulation pattern and direct or indirect human impacts that occur in each arm of the estuary.

Distribution of siphonophores, chaetognaths, euphausiids and oceanographic conditions in the fjords and channels of southern Chile

Abstract: Interior waters of the fjords and channels of southern Chile (415°S–56°S) receive inputs of Subantarctic Water, Equatorial Subsuperficial Water and Western Pacific Subsurface Water from the adjacent Pacific Ocean by means of numerous connecting channels that lead inward from the ocean margin These waters become mixed in the interior zone with freshwater from precipitation, river flow, and meltwater from cordilleran glaciers A two-layered positive estuarine circulation becomes established, with a superficial layer having a net movement towards the adjacent ocean, and a deep layer with net movement towards the fjords The biomass of the interior waters is composed principally of planktonic crustaceans (copepods and euphausiids), chaetognaths, and gelatinous carnivores In a southerly direction, decreases are observed in biomass, in relative abundance, and in species diversity of siphonophores, chaetognaths, and euphausiids Only a few species have been able to adapt successfully to the extreme oceanographic conditions typical of the region, reflected in dominant monospecific populations such as Muggiaea atlantica, Sagitta tasmanica, and Euphausia vallentini The zooplankton fauna of interior waters, characterized by its low degree of specific richness, is made up of a mixture of species typical of Subantarctic Water (Sagitta tasmanica, S decipiens, Euphausia lucens, Nematoscelis megalops, Thysanoessa gregaria), antarctic water (Pyrosthephos vanhoeffeni, Dimophyes arctica, Sagitta marri, S gazellae, Eukrohnia hamata, E bathyantarctica, Euphausia vallentini), temperate and warm epipelagic waters (Eudoxoides spiralis, Lensia conoidea, Chelophyes appendiculata, Muggiaea atlantica, Sphaeronectes gracilis, S fragilis, Abylopsis tetragona, Sagitta enflata), and mesopelagic water (Physophora hydrostatica, Stylocheiron maximum, Vogtia pentacantha, V serrata)