Tracking ongoing transboundary marine distributional range shifts in the digital era

Abstract

The digitalization of society is providing new opportunities to track spatio-temporal redistribution of species across national boundaries in near real-time. This is particularly interesting for marine species for which dynamics are difficult to monitor. We took advantage of the ongoing northward distributional range shift of the white grouper Epinephelus aeneus in Italy, Spain and France (Mediterranean Sea) to test the performance and complementarity of 4 emerging digital methods: (1) local ecological knowledge of recreational fishers actively collected using social media; (2) passive data mining of recreational fishing on social media; (3) Wikipedia page views; and (4) Google search volumes. We compared the temporal changes in maximum latitude of occurrence of the species from local ecological knowledge, passive data mining and traditional scientific knowledge and matched it with the thermal habitat of the species. Moreover, we compared the Wikipedia page views and Google search volumes to assess whether societal interest has a relationship with the distributional range shift of the species. Local ecological knowledge and passive data mining on social media complement traditional scientific knowledge, but are more sensitive as suggested by their significant relationship with the thermal habitat of the species. Wikipedia page views and Google search volumes were higher in Italy where the species is more common, but temporal trends within countries did not agree with changes in the distribution, and likely reflect local societal interest. Digital methodologies can complement traditional scientific knowledge with limited associated costs and with the additional ability to provide social insights for species on the move.