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L'identità di un pesce luna di notevoli dimensioni, spiaggiato nel 1999 su un litorale del mar Adriatico nord-occidentale, è stata corretta da Mola mola (Linnaeus, 1758) a Mola alexandrini (Ranzani, 1839), tenendo in considerazione le recenti revisioni tassonomiche della famiglia Molidae. Il modello in fibra di vetro che riproduce fedelmente l'esemplare è esposto al Museo Civico di Storia Naturale di Comiso, Ragusa, Italia. La segnalazione della specie è la seconda accertata nell'Adriatico e una delle poche documentate finora nel Mediterraneo.

The ocean is a soup of its resident species' genetic material, cast off in the forms of metabolic waste, shed skin cells, or damaged tissue. Sampling this environmental DNA (eDNA) is a potentially powerful means of assessing whole biological communities, a significant advance over the manual methods of environmental sampling that have historically dominated marine ecology and related fields. Here, we estimate the vertebrate fauna in a 4.5-million-liter mesocosm aquarium tank at the Monterey Bay Aquarium of known species composition by sequencing the eDNA from its constituent seawater. We find that it is generally possible to detect mitochondrial DNA of bony fishes sufficient to identify organisms to taxonomic family- or genus-level using a 106 bp fragment of the 12S ribosomal gene. Within bony fishes, we observe a low false-negative detection rate, although we did not detect the cartilaginous fishes or sea turtles present with this fragment. We find that the rank abundance of recovered eDNA sequences correlates with the abundance of corresponding species' biomass in the mesocosm, but the data in hand do not allow us to develop a quantitative relationship between biomass and eDNA abundance. Finally, we find a low false-positive rate for detection of exogenous eDNA, and we were able to diagnose non-native species' tissue in the food used to maintain the mesocosm, underscoring the sensitivity of eDNA as a technique for community-level ecological surveys. We conclude that eDNA has substantial potential to become a core tool for environmental monitoring, but that a variety of challenges remain before reliable quantitative assessments of ecological communities in the field become possible.

Ocean sunfish (Mola spp.) have largely been considered as obligate gelativores, but recent research has suggested that they undergo an unusual life history shift. In this study, analyses of bulk and amino acid nitrogen (δ 15N) and carbon (δ 13C) stable isotope ratios were employed to provide detailed insight into ontogenetic variation in sunfish trophic ecology and habitat use and to assess whether any observed patterns were common to populations around the world. Through this combined approach, a clear ontogenetic shift was identified in both trophic ecology and habitat use of ocean sunfish, indicating a complex trophic role that changes from more benthic to pelagic prey on a continuous scale as fish grow larger. The data also revealed strong population structuring with potential to assess connectivity between distinct groupings using isotopic analysis. When combined, these new insights into sunfish ecology may be of value to conservation management teams, indicating a broad ecological role, distinct population clustering and possible trans-Atlantic movements. These results suggest that the current mass bycatch of ocean sunfish may have far-reaching ecological implications and further highlights the growing need for conservation management of this vulnerable genus.

Il 3 giugno 2017, un gruppo di subacquei che ha mappato gli habitat bentonici in una località a sud di Dubrovnik, in Croazia, ha avvistato e fotografato un esemplare gigante di pesce luna accompagnato da un banco di centrolofo viola (Schedophilus ovalis) a una profondità di 40 m. L'esemplare è stato identificato come pesce luna meridionale Mola alexandrini (Ranzani, 1839). Si tratta di una delle poche segnalazioni di questa specie poco conosciuta e trascurata nel mare Adriatico e uno dei pochi casi nell'intero Mediterraneo.

Aim: Conservation management of vulnerable species requires detailed knowledge of their spatial and temporal distribution patterns. Within this context, species distribution modelling (SDM) can provide insights into the spatial ecology of rarely encountered species and is used here to explore the distribution pattern of ocean sunfishes (Mola mola and M. ramsayi). Both species are prone to high levels of bycatch and are classified respectively as Globally Vulnerable and Not Assessed by the IUCN; although their overall range and drivers of distribution remain poorly defined. Here, we constructed suitable habitat models for Mola spp. on a global scale and considered how these change seasonally to provide a much needed baseline for future management. Location: Global. Methods: Sighting records collected between 2000 and 2015 were used to build SDMs and provided the first global overview of sunfish seasonal distribution. Post hoc analyses provided a quantitative assessment of seasonal changes in total range extent and latitudinal shifts in suitable habitat. Results: Mola is a widely distributed genus; however, sightings exhibited significant spatial clustering most notably in coastal regions. SDMs suggested that Mola presence was strongly dependent on sea surface temperatures with highest probability of presence between 16 and 23°C. The models identified significant variation in seasonal range extent with latitudinal shifts throughout the year; although large areas of suitable year-round habitat exist globally. Main conclusions: We provided the first assessment of Mola distribution on a global scale, with evidence of a wide latitudinal range and significant clustering in localized \"hotspots\" (notably between 40–50°N). By assessing the results of SDMs alongside evidence from published satellite tagging studies, we suggest that the species within the genus Mola are highly mobile, acting as facultative seasonal migrants. By identifying key suitable habitat alongside potential movement paths, this study provides a baseline that can be used in active conservation management of the genus.

The ocean sunfish (Mola mola) is typically considered to feed on gelatinous zooplankton, but reports in the literature describe various benthic organisms being found in their stomachs. This might reflect ontogenetic dietary shift, as little was known about the foraging habit of this species. We examined their foraging habits using dietary analyses in combination with a behavioral study in Iwate, Japan (39°22′N, 141°58′E) from 2009 to 2010. Our stomach content analyses (n = 17, 31–250 cm total length) suggested that small sunfish (<50 cm) feed on benthic crustaceans, but large sunfish (>200 cm) feed on jellyfish. Larger sunfish showed higher values of both carbon and nitrogen stable isotope ratios. Deployment of accelerometers and animal-borne cameras on small sunfish in July (49–58 cm, n = 5) suggested their possibility of feeding, while they stayed near the seabed. This indicates that small sunfish might feed on benthic preys. Deployment of accelero-magnetometers on large sunfish in July (84–164 cm, n = 4) clarified that the large sunfish in July swam back and forth between the surface and deep water (>100 m). Temporary decelerations, which were considered to be associated with feeding of planktonic prey, were observed in deep water. Whereas deployment of accelero-magnetometers on large sunfish in November (105 cm, n = 3) showed several bursts, they swam within the mixed layer (0–100 m), which might be associated with chasing of rapid prey. These results suggest that ocean sunfish have heterogeneous diets depending on their body size and possibly season.

Mars is known to host large quantities of water in solid or gaseous form, and surface rocks show clear evidence that there was liquid water on the planet in the distant past. Whether any liquid water remains on Mars today has long been debated. Orosei et al. used radar measurements from the Mars Express spacecraft to search for liquid water in Mars' southern ice cap (see the Perspective by Diez). They detected a 20-km-wide lake of liquid water underneath solid ice in the Planum Australe region. The water is probably kept from freezing by dissolved salts and the pressure of the ice above. The presence of liquid water on Mars has implications for astrobiology and future human exploration. Science , this issue p. 490 ; see also p. 448 Radar data from Mars Express show that there is a lake of liquid water underneath the solid ice of Mars’ southern ice cap. The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

1. Ocean sunfish (Mola mola) were believed to be inactive jellyfish feeders because they are often observed lying motionless at the sea surface. Recent tracking studies revealed that they are actually deep divers, but there has been no evidence of foraging in deep water. Furthermore, the surfacing behaviour of ocean sunfish was thought to be related to behavioural thermoregulation, but there was no record of sunfish body temperature. 2. Evidence of ocean sunfish feeding in deep water was obtained using a combination of an animal-borne accelerometer and camera with a light source. Siphonophores were the most abundant prey items captured by ocean sunfish and were typically located at a depth of 50–200 m where the water temperature was <12 °C. Ocean sunfish were diurnally active, made frequently deep excursions and foraged mainly at 100–200 m depths during the day. 3. Ocean sunfish body temperatures were measured under natural conditions. The body temperatures decreased during deep excursions and recovered during subsequent surfacing periods. Heat-budget models indicated that the whole-body heat-transfer coefficient between sunfish and the surrounding water during warming was 3–7 times greater than that during cooling. These results suggest that the main function of surfacing is the recovery of body temperature, and the fish might be able to increase heat gain from the warm surface water by physiological regulation. 4. The thermal environment of ocean sunfish foraging depths was lower than their thermal preference (c. 16–17 °C). The behavioural and physiological thermoregulation enables the fish to increase foraging time in deep, cold water. 5. Feeding rate during deep excursions was not related to duration or depth of the deep excursions. Cycles of deep foraging and surface warming were explained by a foraging strategy, to maximize foraging time with maintaining body temperature by vertical temperature environment.

Large pelagic fishes often dive and surface repeatedly as if they were airbreathers, raising a question about the functions of these movements. Some species (e.g., bigeye tuna, ocean sunfish) apparently alternate foraging in deep cold waters and rewarming in shallow warm waters. However, it is unclear how prevalent this pattern is among species. Blue sharks are the widest-ranging pelagic shark with expanded vertical niches, providing a model for studying foraging–thermoregulation associations. We used electronic tags, including video cameras, to record the diving behaviour, muscle temperature, and foraging events of two blue sharks. During repeated deep dives (max. 422 m), muscle temperature changed more slowly than ambient water temperature. Sharks shifted between descents and ascents before muscle temperature reached ambient temperature, leading to a narrower range (8 °C) of muscle temperature than ambient temperature (20 °C). 2.5-h video footage showed a shark catching a squid, during which a burst swimming event was recorded. Similar swimming events, detected from the entire tag data (20 − 22 h), occurred over a wide depth range (5 − 293 m). We conclude that, instead of alternating foraging and rewarming, blue sharks at our study site forage and thermoregulate continuously in the water column. Furthermore, our comparative analyses showed that the heat exchange rates of blue sharks during the warming and cooling process were not exceptional among fishes for their body size. Thus, behavioural thermoregulation linked to foraging, rather than enhanced abilities to control heat exchange rates, is likely key to the expanded thermal niches of this ectothermic species.

The genus Mola of ocean sunfishes (family Molidae) is currently composed of three species: Mola mola (Linnaeus 1758), Mola ramsayi (Giglioli 1883), and Mola tecta Nyegaard et al. 2017. For a comprehensive revision of the genus, both literature survey and morphological investigations of Molidae were conducted. We found Mola alexandrini (Ranzani 1839) to be synonymous with M. ramsayi and we herein redescribe M. alexandrini based on the rediscovered dried holotype and 21 other fresh and preserved specimens. Mola alexandrini can be distinguished from other species of Mola by the following combination of characters in adults: head profile with bump; chin with bump; body scales rectangular; clavus rounded, supported by 14–24 (mode 17) clavus fin rays and 8–15 (12) ossicles on the rear margin. A neotype of M. mola is designated for comparison with M. alexandrini, as these two species have long been confused.