Hotspots in the heat: Bayesian spatial modeling of Southern Bluefin Tuna larvae in a warming Argo Basin

M.Granzia Pennino; Barbara A. Muhling; Estrella Malca; Raúl Laiz-Carrión; José M. Quintanilla; Ricardo Borrego-Santos; Manuel Vargas-Yanez; Francisco J Abascal; Lynnath Beckley; Michael R. Landry

doi:10.1016/j.dsr2.2026.105605

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Hotspots in the heat: Bayesian spatial modeling of Southern Bluefin Tuna larvae in a warming Argo Basin

Journal article

Open access

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Hotspots in the heat: Bayesian spatial modeling of Southern Bluefin Tuna larvae in a warming Argo Basin

M.Granzia Pennino, Barbara A. Muhling, Estrella Malca, Raúl Laiz-Carrión, José M. Quintanilla, Ricardo Borrego-Santos, Manuel Vargas-Yanez, Francisco J Abascal, Lynnath Beckley and Michael R. Landry

Deep Sea Research Part II: Topical Studies in Oceanography, Vol.226, 105605

2026

DOI: https://doi.org/10.1016/j.dsr2.2026.105605

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Abstract

Southern bluefin tuna

Larvae

Spatial modeling

INLA

Spawning habitat

Climate change

Indian ocean

The Argo Basin, located in the eastern Indian Ocean off northwestern Australia, is the primary spawning ground for Southern Bluefin Tuna (Thunnus maccoyii). Understanding the environmental drivers of larval distribution in this region is essential to anticipate potential climate impacts. Using data from the BLOOFINZ cruise, we applied spatially explicit Bayesian models with Tweedie likelihoods to evaluate the influence of sea surface temperature, sea level anomaly, sea surface salinity, chlorophyll-a concentration, bathymetry, and seabed aspect on larval density (density standardized by filtered volume). The best-supported model revealed strong nonlinear responses to temperature, mesoscale activity, and depth. Larval density increased with warmer surface waters, peaked at intermediate depths, and was highest under moderate sea level anomalies, suggesting that retention and feeding conditions are maximized under these circumstances. Seabed aspect had a negative effect, consistent with topography-flow interactions that can reduce retention. The spatial component of the model identified a hotspot of larval density in the southern–southwestern basin and lower density toward the north, with lowest uncertainty in well-sampled central areas. Projections for 2050 under a mid-range climate scenario indicated a heterogeneous redistribution of suitable larval habitat, with declines in central and southeastern spawning areas and increases toward the northeast. These findings highlight the sensitivity of Southern Bluefin Tuna larvae to oceanographic conditions and climate change, and they emphasize the need for adaptive, climate-informed management of spawning habitats.

Details

Title: Hotspots in the heat: Bayesian spatial modeling of Southern Bluefin Tuna larvae in a warming Argo Basin
Authors/Creators: M.Granzia Pennino - Institut de Ciències del Mar
Barbara A. Muhling - University of California, Santa Cruz
Estrella Malca - University of Miami
Raúl Laiz-Carrión - Instituto Español de Oceanografía
José M. Quintanilla - Instituto Español de Oceanografía
Ricardo Borrego-Santos - Instituto Español de Oceanografía
Manuel Vargas-Yanez
Francisco J Abascal - Instituto Volcanológico de Canarias
Lynnath Beckley - Murdoch University, Centre for Sustainable Aquatic Ecosystems
Michael R. Landry - Scripps Institution of Oceanography
Publication Details: Deep Sea Research Part II: Topical Studies in Oceanography, Vol.226, 105605
Publisher: Elsevier Ltd.
Number of pages: 8
Identifiers: 991005861088307891
Murdoch Affiliation: Centre for Sustainable Aquatic Ecosystems; Murdoch University
Resource Type: Journal article

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