Spatial and temporal variation of seasonal synchrony in the deep-sea shrimp Aristeus antennatus in the Western Mediterranean

- We analyse space-time seasonal synchrony of a harvested deep-sea red shrimp, Aristeus antennatus.
- Synchronic geographic associations are related to biogeographical patterns of productivity and geomorphologic features.
- Seasonal synchrony varies with time influenced by the climate variation and local environmental processes.
- The most patchy-aggregated population subunit is mainly dependent on local-scale processes.
- Spatial dynamics of primary producers phenology influences broadly distributed population subunits.

Resolving drivers of spatial synchrony in marine species is fundamental for the management and conservation of deep-sea ecosystems. Here we examine an 11-year data set of monthly catches per unit of effort (CPUE) of the red-shrimp Aristeus antennatus. These data comprise 16 locations of two population subunits in the Western Mediterranean, the Catalan coast and the Balearic archipelago. The analysis of their seasonal covariation and its space-time structure showed small-scale geographical segregation of locations linked with the seasonal fluctuations of CPUE. Results further revealed that seasonal synchrony dominates at short spatial scales (ca. 50 km), while asynchrony prevails are broader spatial scales (ca. 200-300 km). This spatial pattern, however, varied over the period examined, although it was specific for each population subunit suggesting contrasting drivers of seasonal synchrony. The Balearic Islands, a patchier population subunit, displayed a seasonal synchrony pattern mainly dependent on biological and oceanographic processes at local scales. By contrast, in the Catalan coast, the pattern appeared related with regional-scale climate, which triggers spatial differences in the phenology of primary producers and the timing of food advection to the seabed. These cascading processes depicted by our investigation shed light on underlying mechanisms shaping the temporal synchrony of broadly distributed deep-sea populations.