Aurita Populations Research Articles

Parasites Diversity, Abundance, Prevalence, and Richness Infecting Didelphis aurita (Didelphimorphia: Didelphidae) in the Atlantic Rainforest, Brazil.

Parasites are key players in ecosystems, influencing population sizes and food webs, yet the impact of environmental factors on their diversity is not well understood. The Atlantic rainforest in Brazil, particularly the Parque Estadual das Fontes do Ipiranga (PEFI), exemplifies a biodiversity hotspot facing significant deforestation, housing diverse animal species such as the synanthropic Brazilian common opossum (Didelphis aurita), which serves as a reservoir for multiple zoonotic pathogens. In this study, we investigated parasite diversity, abundance, prevalence, and richness in free-living D. aurita in the PEFI, São Paulo, Brazil. From January 2015 to January 2017, 101 fecal samples of D. aurita were collected in two areas of PEFI, at the Instituto de Pesquisas Ambientais (IPA) and the Parque de Ciência e Tecnologia (Cientec), and analyzed using three different parasitological methods. In total, 99% of the samples were positive for at least one parasite. The most prevalent parasite belonged to the order Strongylida (82%), followed by Cruzia sp. (77%), the latter having a significantly higher prevalence at IPA. In contrast, Acanthocephala showed greater prevalence at Cientec. Co-infections were common, with some individuals harboring up to seven different parasites. Our findings reveal significant parasite diversity in the D. aurita population at PEFI, including both helminths and protozoan trophozoites, some of which are reported for the first time in this host species. Further research is essential for accurate species identification of the observed parasites.

Effects of temperature and salinity on growth of Aurelia aurita

A three-stage (Medusa-Polyp-Ephyra) life history model of Aurelia aurita is formulated to investigate the role of ephyra and explore the ecological effects of sea surface temperature and seawater salinity on blooms. Both theoretical analyses and numerical simulations explain the mechanisms of A. aurita blooms in specific seasons. Sensitivity analyses (SAs) characterize the key factors that affect population sizes and provide a basis for feasible and effective control recommendations. In agreement with observational data, we then summarize the interannual variation patterns in the A. aurita population in Jiaozhou Bay and generalize its distribution in the Yellow Sea. This study shows that the occurrence of strobilation, ephyra development, and degree of asexual reproduction can significantly influence the steady states of A. aurita. Moreover, the population size of medusae is sensitive to medusa mortality and strobilation. The findings provide some valuable insights into revealing the mechanisms of A. aurita blooms and explain the connection between its population dynamics and environmental factors.

A Modeling Study on Population Dynamics of Jellyfish Aurelia aurita in the Bohai and Yellow Seas

Jellyfish blooms have become a marine environmental issue with detrimental effects on marine ecosystems around the world. The jellyfish Aurelia aurita is one of dominant species of blooms worldwide and also in the Bohai and Yellow Seas (BYSs) of China. To investigate population dynamics and controlling factors on population biomass, a complex population-dynamic model is developed for jellyfish of A. aurita in the BYSs that includes three components, namely, a three-dimensional coupled physical–biogeochemical model, a Lagrangian particle-tracking model, and an energy balance model for the jellyfish life cycle. By comparison, the model well reproduces the individual growth and seasonal evolution of A. aurita population. During individual growth period, the temperature is a key factor controlling growth and dry weight, characterized by a nearly linear growth rate. Longer period tends to favor larger medusa size and further to promote the biomass. The yearly peak biomass shows interannual variations that are controlled by the jellyfish magnitude, food concentration, and effective accumulative temperature of growth, with their contributions quantified through statistical analyses. Only considering the effect of temperature, the yearly peak biomass can be obtained through the durations of suitable temperature ranges for strobilization and individual growth that determines the magnitude and the averaged individual weight, respectively, with longer strobilation duration leading to higher magnitude. The simplified statistical relationships would favor to understand the temperature control on population dynamics of A. aurita.

Spatial Distribution, Population Structure, and Predatory Impact of Gelatinous Predators on Zooplankton Community in Inshore Waters off Crimean Coast of the Black Sea

The study reports the data on the distribution and predatory impact of the gelatinous macroplankton on mesozooplankton in the inshore waters of Crimea in April 2016. In the study areas, gelatinous macroplankton comprised Scyphomedusae Aurelia aurita (Linnaeus, 1758) and three ctenophore species (Mnemiopsis leidyi A. Agassiz, 1865, Beroe ovata Bruguire, 1789, and Pleurobrachia pileus (O. F. Müller, 1776). The biomass of A. aurita dominated everywhere and varied from ~ 62 to 330 g·m‑2 in different areas. The largest A. aurita biomass was observed in the South Coast of Crimea and the smallest in Karkinitsky Bay, where the number of jellyfish was high, suggesting the predominance of small individuals in the population. The size structure of A. aurita population differed by region: the proportion of large animals increased from the West to the East. The abundance and biomass of M. leidyi were rather low: 0.33–1.45 ind·m‑2 and 1–51.7 g·m‑2, respectively (the exception was the position in the Kerch Strait, where M. leidyi abundance reached 2 ind. m‑2 and biomass 126.3 g·m‑2); that species occurred only at 33–45 % of the stations (the exception was Karkinitsky Bay – 17 %), with the maximum values in the South Coast of Crimea. Large, 55–70-mm, adult individuals predominated. P. pileus biomass was lower than the biomass of A. aurita and M. leidyi in all areas, but its abundance was much higher. The daily rations of A. aurita varied widely both in the entire area and from one region to another. The daily ration values correlated with the carbon content in A. aurita body. The predation pressure of A. aurita on zooplankton in the inshore waters of Crimea was very low and did not result in a crucial decrease in mesozooplankton abundance. The effect of M. leidyi, even with its low abundance and biomass, was much stronger

New records for <i>Callithrix aurita</i> and <i>Callithrix </i>hybrids in the region of Viçosa, Minas Gerais, Brazil


 
 
 The genus Callithrix includes six species distributed across eastern Brazil in the Atlantic Rainforest, Caatinga, and Cerrado biomes. The buffy-tufted-ear marmoset (Callithrix aurita) is endemic to the Atlantic Rainforest and occurs in the states of Minas Gerais, Rio de Janeiro, and São Paulo. This species is considered ‘Endangered’ and listed among the world’s 25 most threatened primates. The release into the wild of marmosets kept as pets has led to numerous invasive populations in southeastern Brazil, which hybridize with native congeneric species. This, combined with habitat loss and fragmentation, has caused a dramatic decline in C. aurita populations, and threatens them with extinction. The city of Viçosa, in Minas Gerais, has an almost 50-year history of introduced Callithrix species. C. aurita, the native species, was last recorded in the region in 1995. With the aim of updating knowledge on the current situation of Callithrix in the region, we surveyed 43 fragments of the Atlantic Forest in Viçosa and nearby cities between 2017 and 2019. We recorded 22 groups of hybrid forms, three solitary individuals of hybrid marmosets, two mixed groups of C. aurita with hybrids, and a single group of C. aurita. This record of C. aurita was the first of a pure group of the species in the region in 20 years. These results highlight one of the most important threats to C. aurita, and management actions are urgently needed to control invasive and hybrid populations, to allow the endangered buffy-tufted-ear marmoset to recover
 
 

Quantifying top-down control and ecological traits of the scyphozoan Aurelia aurita through a dynamic plankton model

Aurelia aurita (Linneaus, 1758) is a cosmopolitan scyphozoan, probably the most investigated jellyfish in temperate and highly productive coastal ecosystems. Despite a prominent top-down control in plankton food webs, a mechanistic understanding of A. aurita population dynamics and trophic interactions has been barely addressed. Here we develop a food web dynamic model to assess A. aurita role in the seasonal plankton dynamics of the Kiel Fjord, southwestern Baltic Sea. The model couples low trophic level dynamics, based on a classical Nutrient Phytoplankton Zooplankton Detritus (NPZD) model, to a stage-resolved copepod model (referencing Pseudocalanus sp.) and a jellyfish model (A. aurita ephyra and medusa) as consumers and predators, respectively. Simulations showed the relevance of high abundances of A. aurita, which appear related with warm winter temperatures, promoting a shift from a copepod-dominated food web to a ciliate and medusa dominated one. The model captured the intraspecific competition triggered by the medusae abundance and characterized by a negative relationship between population density and individual size/weight. Our results provide a mechanistic understanding of an emergent trait such as size shaping the food web functioning, driving predation rates and population dynamics of A. aurita, driving its sexual reproductive strategy at the end of the pelagic phase.

<i>Callithrix aurita</i>: a marmoset species on its way to extinction in the Brazilian Atlantic Forest


 
 
 The buffy-tufted-ear marmoset (Callithrix aurita) is a small primate endemic to the montane regions of the southeastern Atlantic Forest in Brazil. The species was formerly listed as “Vulnerable” (VU) on the Brazilian Official National List of Threatened Fauna Species, but in December 2014 it was re-classified as “Endangered” (EN) as a result of habitat loss, forest fragmentation and, especially, competition and hybridization with invasive marmosets (Callithrix spp.). This article gives an overview of the current conservation status of and field research on C. aurita that includes the objectives set forth by the C. aurita Conservation Project (spearheaded in December 2014 by a group of C. aurita researchers), and the related set of integrated conservation actions. These actions include expanded geographical surveys of C. aurita populations, improvements to a captive C. aurita breeding program, and the establishment of new protected areas as part of a C. aurita metapopulation management program. Despite these current efforts, however, the strengthening and consolidation of urgent conservation actions to protect the buffy-tufted-ear marmoset still depend on a variety of factors, including increased institutional collaboration and augmented financial support. Enhancing institutional and financial backing for C. aurita conservation will improve our understanding of the various challenges involved and, facilitate the rapid development of alternative strategies to mitigate ongoing threats to the species.
 
 

Amiad Filtration Systems Ltd, Israel

This study assessed the impact of secondary hard substrate, as being introduced into marine ecosystems by the establishment of wind farm pillars, on the occurrence and distribution of the moon jelly Aurelia aurita in the southwestern Baltic Sea. A two-year data sampling was conducted with removable settlement plates to assess the distribution and population development of the scyphozoan polyps. The data collected from these samples were used to set up a model with Lagrangian particle technique. The results confirm that anthropogenic created hard substrate (e.g. offshore wind farms) has the potential to increase the abundance of the A. aurita population. The distribution of wind farm borne jellyfish along Danish, German and Polish coasts indicates conflicts with further sectors, mainly energy and tourism.

Outotec Oyj, Finland

This study assessed the impact of secondary hard substrate, as being introduced into marine ecosystems by the establishment of wind farm pillars, on the occurrence and distribution of the moon jelly Aurelia aurita in the southwestern Baltic Sea. A two-year data sampling was conducted with removable settlement plates to assess the distribution and population development of the scyphozoan polyps. The data collected from these samples were used to set up a model with Lagrangian particle technique. The results confirm that anthropogenic created hard substrate (e.g. offshore wind farms) has the potential to increase the abundance of the A. aurita population. The distribution of wind farm borne jellyfish along Danish, German and Polish coasts indicates conflicts with further sectors, mainly energy and tourism.

Ahlstrom-Munksjö Oyj, Finland

This study assessed the impact of secondary hard substrate, as being introduced into marine ecosystems by the establishment of wind farm pillars, on the occurrence and distribution of the moon jelly Aurelia aurita in the southwestern Baltic Sea. A two-year data sampling was conducted with removable settlement plates to assess the distribution and population development of the scyphozoan polyps. The data collected from these samples were used to set up a model with Lagrangian particle technique. The results confirm that anthropogenic created hard substrate (e.g. offshore wind farms) has the potential to increase the abundance of the A. aurita population. The distribution of wind farm borne jellyfish along Danish, German and Polish coasts indicates conflicts with further sectors, mainly energy and tourism.

Insights on stock structure of round sardinella Sardinella aurita off north‐west Africa based on otolith shape analysis

This study examines the geographic variability in otolith shape of round sardinella Sardinella aurita as a tool for stock discrimination. Fish were analysed from six sampling locations from Senegal to the Mediterranean coast of Morocco. A combination of otolith shape indices and elliptic Fourier descriptors was investigated by multivariate statistical procedures. Within the studied area, three distinct groups were identified with an overall correct classification of 78%. Group A: Nador (Alboran Sea), group B: Casablanca (northern Morocco) and group C: Senegalese-Mauritanian. The results of this study confirm the absence of an Atlantic Ocean-Mediterranean Sea transition for this species, the Gibraltar Strait acting as an efficient barrier for S. aurita population separation. Off north-west Africa, fish from northern Morocco form a single group which is clearly isolated from Senegalese-Mauritanian waters, confirming the existence of a distinct stock in this area. Among group C, some discontinuity exists and suggests the existence of a sedentary fraction of S. aurita in northern Mauritania (Arguin Bank). The results are discussed in relation to oceanographic features and physical barriers to dispersal and fish management strategy in the study area.

Population dynamics and factors controlling somatic degrowth of the common jellyfish, Aurelia aurita, in a temperate semi-enclosed cove (Kertinge Nor, Denmark)

Life expectancy of the scyphomedusa Aurelia aurita seems closely linked to seasonal shrinkage, or somatic degrowth, which occurs synchronously with sexual reproduction in temperate regions. In the present study, the mechanisms controlling body mass losses and subsequent disappearance of medusae were examined by following seasonal dynamics in population density, individual size, and sexual reproduction of A. aurita during 2013 and 2014 in the shallow, semi-enclosed Kertinge Nor, and the adjacent Great Belt, Denmark. After sexual maturation in early summer, medusae were characterized by a distinct phase of somatic degrowth, expressed by weight-specific individual growth rates of −0.5 to −1.4 % day−1, which was followed by the absence of A. aurita populations in both ecosystems during winter. The number of planula larvae per female (N L , ind.) was positively correlated with medusa diameter (d, mm), following the exponential relationship N L = 160.8 × e 0.029d . The percentage of body mass made up by planulae ranged from 6 to 11 % in Kertinge Nor and 10 to 33 % in Great Belt. ≤15 % of total size-specific body mass losses were due to the release of planulae in Kertinge Nor, suggesting shortage of zooplankton prey during autumn as main factor causing degrowth in A. aurita. Starving medusae produced significantly fewer oocytes and revealed increased mortality compared to well-fed individuals in supplementary laboratory experiments, indicating that degrowth controls the energetic investment into sexual reproduction. Seasonal variability in food supply, rather than energy allocation to reproduction, appears to shorten life spans of A. aurita medusae in temperate Danish waters.

Impact of secondary hard substrate on the distribution and abundance of Aurelia aurita in the western Baltic Sea

This study assessed the impact of secondary hard substrate, as being introduced into marine ecosystems by the establishment of wind farm pillars, on the occurrence and distribution of the moon jelly Aurelia aurita in the southwestern Baltic Sea. A two-year data sampling was conducted with removable settlement plates to assess the distribution and population development of the scyphozoan polyps. The data collected from these samples were used to set up a model with Lagrangian particle technique. The results confirm that anthropogenic created hard substrate (e.g. offshore wind farms) has the potential to increase the abundance of the A. aurita population. The distribution of wind farm borne jellyfish along Danish, German and Polish coasts indicates conflicts with further sectors, mainly energy and tourism.

High genetic homogeneity of the moon jelly Aurelia aurita (Scyphozoa, Semaeostomeae) along the Mediterranean coast of Tunisia

The moon jelly Aurelia aurita is one of the most common and widespread species of scyphomedusa in the Mediterranean Sea. In all, 18 allozyme loci were studied to investigate the genetic variation and population structure of 11 A. aurita populations from the Tunisian coast. Polymorphism was detected at 14 loci across the sampling localities. Gene frequency differences rather than alternative fixation of alleles characterised the collecting sites. The mean number of alleles per locus ranged from 1.89 to 2.17 (average 2.02), and the mean values of observed (H o) and expected (H e) heterozygosities ranged from 0.20 to 0.36 and from 0.32 to 0.37 respectively. Five out of 14 polymorphic loci were out of Hardy-Weinberg equilibrium (H-WE). Likewise, the multilocus tests showed deviation from H-WE in six populations. These populations apparently showed heterozygote deficiency, whereas the average heterozygosity for the remaining ones is quite similar to the expected values. Despite extensive sampling across a microgeographical scale and genotyping efforts, the populations of A. aurita under study showed an absence of genetic differentiation under the background of high gene flow (mean F ST = 0.01, p < 0.05) and higher value of N e m, suggesting that A. aurita is genetically homogeneous throughout the study area. The absence of population genetic structuring may be associated with environmental conditions and life-history parameters.

Population biomass, feeding, respiration and growth rates, and carbon budget of the scyphomedusa Aurelia aurita in the Inland Sea of Japan

We investigated the seasonal occurrence, wet : dry : carbon : nitrogen weight ratios, population biomass, gastric pouch contents, and rates of feeding, growth and respiration of the scyphomedusa Aurelia aurita in the central part of the Inland Sea of Japan. Aurelia aurita medusae began to appear in January/ February as ephyrae, reached annual maximum body size in July/August, and disappeared, presumably due to death, by November. Initial slow growth in early spring was followed by a period of exponentialgrowth(meangrowthrate:0.069d � 1 )betweenAprilandJuly.IntheOndoStrait,whichis characterized by strong tidal mixing, the A. aurita population (mean carbon biomass: 66.0 mg C m � 3 ) overwhelmingly dominated the zooplankton-community biomass (mean biomass of micro- and mesozooplankton: 23.7 mg C m � 3 ) between May and early August The gastric content analysis revealed that A. aurita ate almost all micro- and mesozooplankters, of which small copepods were most important. On the basis of digestion time for small copepods (60 min) and their abundance in the gastric pouch of field-collected A. aurita, we determined the weight specific feeding rates and clearance rates. The former increases linearly with increasing copepod abundance, but the latter was relatively constant irrespective of the food supply. We also measured the respiration rates of A. aurita and expressed them as functions of body weight and temperature. These physio-ecological parameters enabled us to construct the carbon budget of the A. aurita population typical of early summer in the Ondo Strait. Predicted population-feeding rate (6.07 mg C m � 3 d � 1 ) was higher than the population-food requirement for both metabolism and growth (4.55 mg C m � 3 d � 1 ), indicating that food supply was sufficient to sustain the observed growth rate. This feeding rate was equivalent to 26% of microand mesozooplankton biomass, a significant impact on zooplankton.

Reproduction and life history strategies of the common jellyfish, Aurelia aurita, in relation to its ambient environment

The scyphozoan Aurelia aurita (Linnaeus) is a cosmopolitan species, having been reported from a variety of coastal and shelf sea environments around the world. It has been extensively studied over the last 100 years or so, and examination of the literature reveals three striking features: (1) the presence of populations in a wide range of environmental conditions; (2) large inter-population differences in abundance and life history patterns over large and small spatial scales; and (3) inter-annual variability in various aspects of its population dynamics. A. aurita is clearly a highly flexible species that can adapt to a wide range of environmental conditions. While various physiological and behavioural characteristics explain how A. aurita populations can take advantage of their surrounding environment, they do not explain what governs the observed temporal and spatial patterns of abundance, and the longevity or lifespan of populations. Understanding these features is necessary to predict how bloom populations might form. In a given habitat, the distribution and abundance of benthic marine invertebrates have been found to be maintained by four factors: larval recruitment (sexual reproduction), migration, mortality and asexual reproduction. The aims of this review are to determine the role of reproduction and life history strategies of the benthic and pelagic phases of A. aurita in governing populations of medusae, with special attention given to the dynamic interaction between A. aurita and its surrounding physical and biological environment.

Sexual reproduction of the scyphomedusa Aurelia aurita in relation to temperature and variable food supply

The effects of food availability and temperature on sexual maturation and female reproductive output of the scyphomedusa Aurelia aurita was examined in two populations from the contrasting environments of Southampton Water and Horsea Lake, England. Trends in oogenesis and subsequent reproductive output differed markedly between the two populations. In Southampton Water, the onset of sexual maturation occurred earliest in the larger medusae, but eventually all females became ripe, the smallest being 45 mm bell diameter (BD). The decrease in minimum size at maturity was correlated with increasing temperature. In A. aurita from Horsea Lake, size at maturity varied on a seasonal basis, with the smallest ripe female being only 19 to 20 mm BD. There were spring and autumn periods of sexual maturation in this population. During the autumn period, it is likely that food limitation was playing a more critical role in determining medusa size, with decreasing temperature indirectly affecting A. aurita by limiting primary and secondary production. In similar-sized ripe medusae, fecundity was greater in Southampton Water, but the planula larvae produced were significantly smaller than those in Horsea Lake. It is suggested that in Horsea Lake, the quality of the larvae are greater in terms of biochemical content to ensure survival of the few gametes produced (i.e. K-strategy). Comparison of the reproductive effort of the two A. aurita populations revealed that medusae from Southampton Water, which experience greater food availability, are able to direct more energy to reproduction than Horsea Lake medusae. In the latter, A. aurita medusae appear to partition the available food resources into either somatic growth (and therefore increased future fecundity) when food is abundant, or reproductive growth when food is scarce.

Biological structure in a shallow cove (Kertinge Nor, Denmark) — Control by benthic nutrient fluxes and suspension-feeding ascidians and jellyfish

Abstract In 1991 Kertinge Nor was characterized by a high benthic autotrophic biomass dominated by the filamentous macroalga Chaetomorpha linum which reduced the flux of inorganic nitrogen and phosphorus from the sediment to the water column. A dense population of filter-feeding ascidians Ciona intestinalis (up to 270 individuals m-2) had a significant controlling impact on the phytoplankton biomass. Also, small jellyfish Aurelia aurita were present in extremely high densities (up to 300 individuals m-3) controlling the zooplankton population. During a long period of calm and warm weather in the summer of 1992 the filamentous algal mat rose from the sediment surface. High amounts of nutrients were then released to the water column causing a phytoplankton bloom (up to 120 µg chlorophyll a l-1), but the zooplankton biomass remained low due to intense predation by theA. Aurita population. It is concluded that Kertinge Nor is an unstable eutrophic ecosystem in which interactions between suspension-feeding org...

Estimation of food demands ofAurelia auritamedusae populations in the Kiel Bight/Western Baltic

Abstract Using previously published data on respiration, body growth and reproduction, the food demands of the Kiel Bight Aurelia aurita populations in 1982 and 1983 were estimated according to the carbon budget approach. In 1982, medusae abundance and biomass were high and food demands accounted for 37 g C 100 m-3 season-1, whereas in 1983 a low Aurelia stock was associated with a food demand of only 7 g C 100 m-3 season-1. On average, medusae consumption made up roughly 40% and 8% of summer secondary production in 1982 and 1983, respectively. A comparison of Aurelia biomass values determined during six years revealed that the conditions in 1983 are typical for Kiel Bight, whereas in 1982 exceptionally high biomass and feeding rates were observed. It is therefore concluded that grazing impact of medusae is of comparatively low importance in most years.