The pelagic stingray Pteroplatytrygon violacea is known to be a frequent by-catch in longline fisheries worldwide. This study analysed the eco-geographic, technical and temporal parameters that affect pelagic stingray by-catch by the Spanish surface drifting longline fleet that operates in the Mediterranean Sea. Between 2000 and 2013, 3007 longline fishing operations were monitored. Over this period, we recorded 57 574 pelagic stingray by-catches by this fleet. Two gear types were involved in 96.05% of the pelagic stingray by-catch observed: traditional surface longliners targeting swordfish (LLHB) and surface drifting longliners targeting albacore (LLALB). We obtained two statistically significant explanatory models for the two types of gear. In both cases, two of the most important variables were fisheries being sited over the continental shelf and fishing during the summer season. The LLHB explanatory model included the following variables: number of hooks, latitude where setting started, distance between the ends of the longline, and the spring season. Regarding the LLHB, we found an association between the Capture per Unit Effort of pelagic stingray from favourable sets per year and the North Atlantic Oscillation in the previous year.

The feeding habits of the pelagic stingray (Pteroplatytrygon violacea) were studied using 84 stomachs of specimens caught in the northern Adriatic Sea in the period from April 2004 to October 2005. Percentage of empty stomachs found was overall very low, being a bit bigger in smaller specimens. The diet consisted of two main taxonomic groups such as teleost fish and cephalopods, but few specimens of crustaceans were recorded as well. The main food item was represented by anchovy, while cuttlefish and red band fish represented the alternative preys. Prey size was positively correlated with the size of predator. The proportion of anchovies in the diet grew with size of predator, while the one for red band fish decreased. The stingray was confirmed to be a top predator of pelagic fish species, although the presence of benthic prey shows that it feeds also at the bottom.

The present study analyses the spatial and temporal distribution of the pelagic stingray (Pteroplatytrygon violacea) in the south-western Atlantic Ocean, based on data collected between April 1998 and March 2006 by the National Observers Program of the Uruguayan Tuna Fleet. During this period, data were recorded on 51 commercial fishing trips, in which a total of 2 306 851 hooks were set and 2740 stingrays captured. Of these, the sex was determined for 1329 individuals and the size for 944. The average disc width was 47 ± 8 cm (range: 24–82 cm) for females and 44 ± 5 cm (range: 28–84 cm) for males. The results indicate that the species seems to prefer warm temperate and tropical waters. There were no capture records in waters at <15.3 °C. The data collected suggest a mating season in late spring with a gestation period of 2 to 4 months and births occurring during late summer and early autumn. The increasing bycatch of this ovoviviparous species in pelagic longline fisheries, with an unknown survival rate after discard, coupled to its low reproductive potential, call for better monitoring in order to accurately determine its current conservation status.