title: Dynamic habitat suitability modelling reveals rapid poleward distribution shift in a mobile apex predator.
abstract: Many taxa are undergoing distribution shifts in response to anthropogenic climate change. However, detecting a climate signal in mobile species is difficult due to their wide-ranging, patchy distributions, often driven by natural climate variability. For example, difficulties associated with assessing pelagic fish distributions have rendered fisheries management ill-equipped to adapt to the challenges posed by climate change, leaving pelagic species and ecosystems vulnerable. Here, we demonstrate the value of citizen science data for modelling the dynamic habitat suitability of a mobile pelagic predator (black marlin, Istiompax indica) within the south-west Pacific Ocean. The extensive spatial and temporal coverage of our occurrence data set (n = 18 717), collected at high resolution (~1.85 km(2) ), enabled identification of suitable habitat at monthly time steps over a 16-year period (1998-2013). We identified considerable monthly, seasonal and interannual variability in the extent and distribution of suitable habitat, predominately driven by chlorophyll a and sea surface height. Interannual variability correlated with El Nino Southern Oscillation (ENSO) events, with suitable habitat extending up to ~300 km further south during La Nina events. Despite the strong influence of ENSO, our model revealed a rapid poleward shift in the geometric mean of black marlin habitat, occurring at 88.2 km decade(-1) . By incorporating multiple environmental factors at monthly time steps, we were able to demonstrate a rapid distribution shift in a mobile pelagic species. Our findings suggest that the rapid velocity of climate change in the south-west Pacific Ocean is likely affecting mobile pelagic species, indicating that they may be more vulnerable to climate change than previously thought.
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Townsville, Qld, 4811, Australia.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Hill
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Townsville, Qld, 4811, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tobin
authors.affiliation: Centre for Tropical Environmental and Sustainability Sciences, College of Marine and Environmental Sciences, James Cook University, Townsville, Qld, 4811, Australia.
authors.forename: April E
authors.initials: AE
authors.lastname: Reside
authors.affiliation: Pepperell Research and Consulting Pty Ltd., P.O. Box 1475, Noosaville DC, Qld, 4566, Australia.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Pepperell
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.|Australian Institute of Marine Science, PMB #3, Townsville MC, Qld, 4810, Australia.
authors.forename: Tom C L
authors.initials: TC
authors.lastname: Bridge
mesh_terms: D063147:Animal Distribution; D000818:Animals; D057231:Climate Change; D017753:Ecosystem; D020387:Food Chain; D008954:Models, Biological; D010140:Pacific Ocean; D010473:Perciformes / Q000502:physiology*
keywords: MaxEnt; apex predator; black marlin (Istiompax indica); boundary current; climate change; distribution shift; habitat suitability; species distribution modelling; tunas and billfishes