Predicting current and future global distributions of whale sharks

The Vulnerable (IUCN) whale shark spans warm and temperate waters around the globe. However, their present-day and possible future global distribution has never been predicted. Using 30 years (1980-2010) of whale shark observations recorded by tuna purse-seiners fishing in the Atlantic, Indian and Pacific Oceans, we applied generalized linear mixed-effects models to test the hypothesis that similar environmental covariates predict whale shark occurrence in all major ocean basins. We derived global predictors from satellite images for chlorophyll a and sea surface temperature, and bathymetric charts for depth, bottom slope and distance to shore. We randomly generated pseudo-absences within the area covered by the fisheries, and included fishing effort as an offset to account for potential sampling bias. We predicted sea surface temperatures for 2070 using an ensemble of five global circulation models under a no climate-policy reference scenario, and used these to predict changes in distribution. The full model (excluding standard deviation of sea surface temperature) had the highest relative statistical support (wAICc  = 0.99) and explained ca. 60% of the deviance. Habitat suitability was mainly driven by spatial variation in bathymetry and sea surface temperature among oceans, although these effects differed slightly among oceans. Predicted changes in sea surface temperature resulted in a slight shift of suitable habitat towards the poles in both the Atlantic and Indian Oceans (ca. 5°N and 3-8°S, respectively) accompanied by an overall range contraction (2.5-7.4% and 1.1-6.3%, respectively). Predicted changes in the Pacific Ocean were small. Assuming that whale shark environmental requirements and human disturbances (i.e. no stabilization of greenhouse gas emissions) remain similar, we show that warming sea surface temperatures might promote a net retreat from current aggregation areas and an overall redistribution of the species.

[1]  C. Mellin,et al.  Ocean‐scale prediction of whale shark distribution , 2012 .

[2]  A. Monadjem,et al.  Developing a Code of Conduct for whale shark interactions in Mozambique , 2010 .

[3]  A. Gannier,et al.  Ecological niches of three teuthophageous odontocetes in the northwestern Mediterranean Sea , 2008 .

[4]  C. Mellin,et al.  Reef size and isolation determine the temporal stability of coral reef fish populations. , 2010, Ecology.

[5]  E. Chassot,et al.  SOME PRELIMINARY RESULTS ON TUNA DISCARDS AND BYCATCH IN THE FRENCH PURSE SEINE FISHERY OF THE EASTERN ATLANTIC OCEAN , 2009 .

[6]  W. Heyman,et al.  Diver ecotourism and disturbance to reef fish spawning aggregations: it is better to be disturbed than to be dead. , 2010 .

[7]  P. Pravin.  Whale shark in the Indian coast - Need for conservation , 2000 .

[8]  Corey J. A. Bradshaw,et al.  At-sea distribution of female southern elephant seals relative to variation in ocean surface properties , 2004 .

[9]  J. Elith,et al.  Species Distribution Models: Ecological Explanation and Prediction Across Space and Time , 2009 .

[10]  Barry W. Brook,et al.  Multi‐model climate projections for biodiversity risk assessments , 2011 .

[11]  M. Edwards,et al.  Impact of climate change on marine pelagic phenology and trophic mismatch , 2004, Nature.

[12]  Anthony C. Davison,et al.  Bootstrap Methods and Their Application , 1998 .

[13]  L. Compagno,et al.  Sharks of the world :an annotated and illustrated catalogue of shark species known to date , 1984 .

[14]  R. Hueter,et al.  An Unprecedented Aggregation of Whale Sharks, Rhincodon typus, in Mexican Coastal Waters of the Caribbean Sea , 2011, PloS one.

[15]  C. Bradshaw,et al.  Biophysical correlates of relative abundances of marine megafauna at Ningaloo Reef, Western Australia , 2007 .

[16]  L. Hannah,et al.  Climate change‐integrated conservation strategies , 2002 .

[17]  M. Araújo,et al.  Validation of species–climate impact models under climate change , 2005 .

[18]  R. Enríquez-Andrade,et al.  Community-based management through ecotourism in Bahia de los Angeles, Mexico , 2007 .

[19]  F. Jiguet,et al.  Selecting pseudo‐absences for species distribution models: how, where and how many? , 2012 .

[20]  Beau B. Gregory,et al.  Rapid biogeographical plankton shifts in the North Atlantic Ocean , 2009 .

[21]  Damien A. Fordham,et al.  Strengthening forecasts of climate change impacts with multi‐model ensemble averaged projections using MAGICC/SCENGEN 5.3 , 2012 .

[22]  Jacob Cohen.  A Coefficient of Agreement for Nominal Scales , 1960 .

[23]  F. Carvalho,et al.  Ecological risk assessment of pelagic sharks caught in Atlantic pelagic longline fisheries , 2010 .

[24]  C. Parmesan.  Ecological and Evolutionary Responses to Recent Climate Change , 2006 .

[25]  David R. Anderson,et al.  Multimodel Inference , 2004 .

[26]  A. Pearce,et al.  The Seasonal Aggregation of Whale Sharks at Ningaloo Reef, Western Australia: Currents, Migrations and the El Niño/ Southern Oscillation , 2001, Environmental Biology of Fishes.

[27]  D. Rowat.  Occurrence of whale shark (Rhincodon typus) in the Indian Ocean : A case for regional conservation , 2007 .

[28]  T. Reichler,et al.  How Well Do Coupled Models Simulate Today's Climate? , 2008 .

[29]  Jennifer A McKinney,et al.  Feeding habitat of the whale shark Rhincodon typus in the northern Gulf of Mexico determined using species distribution modelling , 2012 .

[30]  C. Mellin,et al.  Spatial and temporal predictions of inter-decadal trends in Indian Ocean whale sharks , 2013 .

[31]  Bai-lian Li,et al.  Temperature-associated upper limits to body size in terrestrial poikilotherms , 2005 .

[32]  J. Reynolds,et al.  Climate Change and Distribution Shifts in Marine Fishes , 2005, Science.

[33]  J. O’Hanley,et al.  Adapting landscapes to climate change: examples of climate-proof ecosystem networks and priority adaptation zones , 2008 .

[34]  Stephen D. Turnbull,et al.  Rare Occurrence of a Rhincodon typus (Whale Shark) in the Bay of Fundy, Canada , 2006 .

[35]  J. Birrien,et al.  Seasonal changes of dissolved organic matter (C, N, P) in permanently well mixed temperate waters , 1984 .

[36]  A. Richardson,et al.  Under-Resourced, Under Threat , 2008, Science.

[37]  Mark G. Meekan,et al.  Movements of whale sharks (Rhincodon typus) tagged at Ningaloo Reef, Western Australia , 2006 .

[38]  J. Correia,et al.  First record of a whale shark Rhincodon typus in continental Europe. , 2012, Journal of fish biology.

[39]  Rafael Bravo de la Parra,et al.  Feeding anatomy, filter-feeding rate, and diet of whale sharks Rhincodon typus during surface ram filter feeding off the Yucatan Peninsula, Mexico. , 2010, Zoology.

[40]  D. Rowat,et al.  A review of the biology, fisheries and conservation of the whale shark Rhincodon typus. , 2012, Journal of fish biology.

[41]  Damien A. Fordham,et al.  Tools for integrating range change, extinction risk and climate change information into conservation management , 2013 .

[42]  A. Gallagher,et al.  Ecological risk assessment and its application to elasmobranch conservation and management. , 2012, Journal of fish biology.

[43]  Stuart I. Rogers,et al.  Climate change and deepening of the North Sea fish assemblage: a biotic indicator of warming seas , 2008 .

[44]  R. Rees,et al.  Evidence of continued hunting of whale sharks Rhincodon typus in the Maldives , 2009, Environmental Biology of Fishes.

[45]  Steven J. Phillips,et al.  Sample selection bias and presence-only distribution models: implications for background and pseudo-absence data. , 2009, Ecological applications : a publication of the Ecological Society of America.

[46]  B. Kjerfve,et al.  Whale sharks Rhincodon typus aggregate to feed on fish spawn in Belize , 2001 .

[47]  L. Fang,et al.  Embryos of the Whale Shark, Rhincodon typus: Early Growth and Size Distribution , 1997 .

[48]  A. Peterson,et al.  The crucial role of the accessible area in ecological niche modeling and species distribution modeling , 2011 .

[49]  Á. Quirós.  Tourist compliance to a Code of Conduct and the resulting effects on whale shark (Rhincodon typus) behavior in Donsol, Philippines , 2007 .

[50]  R. Betts,et al.  Climate Change, Deforestation, and the Fate of the Amazon , 2008, Science.

[51]  P. Psomadakis,et al.  Mediterranean fish biodiversity: an updated inventory with focus on the Ligurian and Tyrrhenian seas , 2012 .

[52]  M. Thums,et al.  Evidence for behavioural thermoregulation by the world's largest fish , 2013, Journal of The Royal Society Interface.

[53]  D. Jessup.  Opportunistic research and sampling combined with fisheries and wildlife management actions or crisis response. , 2003, ILAR journal.

[54]  Antoine Guisan,et al.  Predictive habitat distribution models in ecology , 2000 .

[55]  O. Phillips,et al.  Extinction risk from climate change , 2004, Nature.

[56]  A. Gutierrez,et al.  Climate change effects on poikilotherm tritrophic interactions , 2008 .

[57]  C. Bradshaw,et al.  Inferred global connectivity of whale shark Rhincodon typus populations. , 2013, Journal of fish biology.

[58]  Damien A. Fordham,et al.  Conservation management and sustainable harvest quotas are sensitive to choice of climate modelling approach for two marine gastropods , 2013 .

[59]  J. Edmonds,et al.  Scenarios of Greenhouse Gas Emissions and Atmospheric Concentrations , 2007 .

[60]  L. Fahrig.  Effects of Habitat Fragmentation on Biodiversity , 2003 .

[61]  W. Thuiller.  BIOMOD – optimizing predictions of species distributions and projecting potential future shifts under global change , 2003 .

[62]  C. Bradshaw,et al.  Decline in whale shark size and abundance at Ningaloo Reef over the past decade: The world's largest fish is getting smaller , 2008 .

[63]  Mark New,et al.  Ensemble forecasting of species distributions. , 2007, Trends in ecology & evolution.

[64]  K. Taylor.  Summarizing multiple aspects of model performance in a single diagram , 2001 .

[65]  J. Smart,et al.  Diving behaviour of whale sharks in relation to a predictable food pulse , 2006, Journal of The Royal Society Interface.

[66]  M. Kearney,et al.  Mechanistic niche modelling: combining physiological and spatial data to predict species' ranges. , 2009, Ecology letters.

[67]  Walter Jetz,et al.  Global patterns and predictors of marine biodiversity across taxa , 2010, Nature.

[68]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[69]  Oar,et al.  Climate Change Effects , 2016 .

[70]  C. Bradshaw,et al.  Seaweed Communities in Retreat from Ocean Warming , 2011, Current Biology.

[71]  Miguel B. Araújo,et al.  Life on a tropical planet: niche conservatism and the global diversity gradient , 2013 .

[72]  C. Bradshaw,et al.  Scarring patterns and relative mortality rates of Indian Ocean whale sharks , 2008 .