Original provider: Giuseppe Notarbartolo di Sciara, Tethys Research Institute Dataset credits: Tethys Research Institute Abstract: The giant devil ray Mobula mobular, the only Mediterranean mobulid, is subject to mortality caused by directed and accidental captures in fisheries throughout the region. Whilst the combination of human impacts, limited range and a low reproductive potential is not inconsistent with its endangered listing, there are insufficient data to enable a quantitative assessment of trends. Without this, it is difficult to assess and prioritise threats and develop effective conservation actions. Using results from aerial surveys conducted between 2009 and 2014 over the Ligurian, Corsican, Sardinian, northern and central Tyrrhenian seas (626,228 km2), this study provides the first quantitative information on giant devil ray abundance and habitat choice in the western Mediterranean. Devil rays were observed in all seasons except winter, with their estimated abundance in the study area peaking in summer. The overall uncorrected mean density in the study area during summer was estimated at 0.0257 individuals km-2 (range: 0.017–0.044), resulting in a total abundance estimate of 6,092 (12.7%CV) individuals at the surface; once corrected for availability bias, this estimate indicates a summer presence of >12,700 devil rays in the study area. Rays were mostly observed alone even if occasionally, larger aggregations up to a maximum of 18 individuals were observed. Although observed throughout the study area, spatial modelling identified their preferred habitat to be over a broad strip connecting the Tuscan Archipelago to Eastern Sardinia, over a wide range of water depths ranging from 10 to 2000m. The observed seasonal changes in giant devil ray distribution in this study, combined with similar evidence from other areas in the Mediterranean, support the hypothesis that the species undertakes latitudinal migrations across the region, taking advantage of highly productive waters in the north during summer, and warmer southern waters during winter. Supplemental information: Some records do not have time part.
The data in this occurrence resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 298 records.
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Researchers should cite this work as follows:
Notarbartolo di Sciara, G. 2016. Giant Devil Rays in the North-Western Mediterranean Sea. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/1370) on yyyy-mm-dd.
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This resource has been registered with GBIF, and assigned the following GBIF UUID: c9b33318-2033-4f94-afcf-e88ba2ddb272. OBIS-SEAMAP publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Ocean Biodiversity Information System.
Occurrence,Marine Animal Survey,Marine Biology,Visual Sighting,Aircraft; Observation; Occurrence
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|Bounding Coordinates||South West [36.266, 5.854], North East [44.301, 19.001]|
Scientific names are based on the Integrated Taxonomic Information System (ITIS).
|Species||Mobula mobular (giant devil ray)|
|Start Date / End Date||2009-07-21 / 2013-08-07|
No Description available
|Title||Giant Devil Rays in the North-Western Mediterranean Sea|
The personnel involved in the project:
Method step description:
|Parent Collection Identifier||OBIS-SEAMAP|
marine, harvested by iOBIS