1
Marine and
Fishery Sciences
MAFIS
*
Random Forest habitat suitability modeling for Acanthurus spp. in
Philippine coral reefs: environmental drivers and climate projections
*
Nelson C. Perante
ABSTRACT. Acanthurus
A. lineatusA. nigricansA. olivaceusA. triostegus
A. xanthopterusA. pyroferus
=
A. olivaceusA. xanthopterus
Acanthurus triostegus A. xanthopterus
Key words:
Modelado de idoneidad de hábitat mediante Bosque Aleatorio para Acanthurus spp. en arrecifes
de coral lipinos: factores ambientales y proyecciones climáticas
RESUMEN.Acanthurus
A. lineatusA. nigricansA. olivaceusA. triostegusA. xanthopterusA.
pyroferus
=
A. olivaceusA. xanthopterus
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
Acanthurus
Acanthurus
Acanthurus
Acanthurus
A. olivaceus
A. pyroferus
Acanthurus triostegus A. xanthopterus
Palabras clave:
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
Acanthurus=
Acanthurus
Acanthurus
+
++
Study area
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
±
Acanthurus
=
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
Species selection and occurrence data
A. lineatus, A. nigricans,
A. olivaceusA. triostegus A. xanthopterus A.
pyroferus
<
∼
>
=A. pyroferus=A.
triostegus
Environmental predictors
∼
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
>
=<
=
==
=
∼
∼
∼
∼
Acanthurus =
A. lineatus
A. nigricans
A. olivaceus
A. triostegus
A. xanthopterus
A. pyroferus
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
=<
Random Forest modeling
Model setup and hyperparameter tuning
A.
xanthopterus
Variable importance and partial dependence
SHAP values
Model evaluation
>
>
Acanthurus
Random forest
Modeling
6 species individually
500 trees, mtry tuned
10-fold spatial CV
OOB error estimation
SHAP importance
Evaluation
AUC / TSS
True Skill Statistic
Boycc Index
Spatial cross-validation
Calibration plots
Outputs
Suitability maps
Variable importance
Partial dependence
Priority reef zones
SSP projections
Data
Acquisition
OBIS / GBIF
occurrence
Records
Benthic surveys
ERMS / MODIS rasters
GEBCO bathymetry
CoralTemp SST
Spatial thinning (5 km)
Spatial bias correction
VIF collinearity filter
10 predictors retained
Raster harmonisation
500 m
Preprocessing
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
=
+
=
Habitat suitability mapping
Climate change projections
±
Multi-species overlap and MPA gap analysis
Acanthurus==
A. lineatus
A. nigricans
A. olivaceus
A. triostegus
A. xanthopterus
A. pyroferus
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
Occurrence data and predictor collinearity
Acanthurus triostegus
=A. pyroferus
=
<
Variable importance and ecological drivers
A. lineatusA. nigricans
A. triostegusA. pyroferus
A. olivaceus A. xan-
thopterus
A. lin-
eatus
A.
lineatus
>Acanthurus xanthopter-
Acanthurus
AB
Coral cover (%)
Rugosity
Depth (m)
Chl-a (mg m)
-3
SST mean (°C)
Wave energy (kJ m)
-2
SST range (°C)
PAR (mol md)
-2 -1
Salinity
Distance to reef edge (km)
Mean Decrease in Gini Impurity (%)
0510 15 20 25
A. line.
A. nigr.
A. oliv.
A. trio.
A. xant.
A. pyro.
A. lineatus
A. nigricans
A. olivaceus
A. triostegus
A. xanthopterus
A. pyroferus
Coral cover (%)
Rugosity
Depth (m)
Chl-a (mg m)
-3
SST mean (°C)
Wave energy (kJ m)
-2
SST range (°C)
PAR (mol md)
-2 -1
Salinity
Distance to reef edge (km
)
1.8
3.8
5.5
7.4
8.1
9.3
11.2
12.8
18.7
21.4
2.1
4.1
6.8
8.7
7.3
12.1
13.4
11.9
15.4
18.2
1.6
3.7
5.3
7.9
9.4
10.7
8.1
16.2
22.8
14.3
1.7
4.3
7.2
9.1
6.8
14.2
12.3
13.4
11.3
19.7
1.5
3.1
5.9
8.8
11.2
8.3
9.8
14.7
24.6
12.1
1.5
3.8
6.4
9.3
8.6
11.4
14.1
10.9
13.2
20.8
25
20
15
10
5
0
Importance (%)
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
us
Current habitat suitability distribution
A. olivaceus A. xanthopterus
>
A. lin-
eatusA. pyroferus
Random Forest model performance
A. xanthopterusA. pyro-
ferus
A.
lineatusA. xanthopterus
Climate change projections
A. xanthopterus
A. triostegus
A. xanthopterusA.
triostegus
A. lineatusA. xan-
thopterus=±
1.0
0.8
0.6
0.4
0.2
0.0
20
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
10.00
1.0
0.8
0.6
0.4
0.2
0.0 20
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
26 20
40 60 80 2340 10 20 30 40 50 60 0.25 0.50 0.75 1.00 1.25 1.50
40 60 80 100 120 25 27 28 29 30 31 0 20 40
60
80 40 60 80
Coral cover (%) Rugosity Depth (m) Chl-a (mg m)
-3
Coral cover (%)SST mean (°C)
Depth (m) Wave energy (kJ m)
-2
A. lineatus
A. xanthopterus
A. lineatusA. lineatusA. lineatus
A. xanthopterusA. xanthopterusA. xanthopterus
Marginal suitability
Marginal suitability
Perante: Random Forest habitat suitability of Acanthurus in the Philippines 11
Acanthurus
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
Multi-species overlap and MPA gap analysis
∼
∼
∼
Acanthurus
==
=
Acanthurus
A. lineatus
A. nigricans
A. olivaceus
A. triostegus
A. xanthopterus
A. pyroferus
==
AB
A. line. A. nigr. A. oliv. A. trio. A. xant. A. pyro.
A. lineatus
A. nigricans
A. olivaceus
Perfect calibration
0.0 0.2 0.4 0.8 1.00.6
0.0
0.2
0.4
0.6
0.8
1.0
Observed occurrence fraction
Mean predicted probability
Metric value
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.94
0.88
0.93
0.92
0.93
0.91
0.94
0.87
0.83
0.84
0.80
0.82 0.82
0.79
0.81
0.86
0.78
0.80
AUC = 0.90 threshold
AUC TSS Boyce Index
TSS = 0.70 threshold
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
∼
∼
×=
Acanthurus=
=
A. lineatus
A. nigricans
A. olivaceus
A. triostegus
A. xanthopterus
A. pyroferus
=
B
SSP1-2.6 2050
SSP1-2.6 2100
SSP2-4.5 2050
SSP2-4.5 2100
SSP5-8.5 2050
SSP5-8.5 2100
A
A. line. A. nigr. A. oliv. A. trio.A. xant. A. pyro.
Change in suitable habitat (%)
0
-5
-10
-15
-20
-25
-30
-35
-40
2020 2030 2040 2050 2060 2080 2090 21002070
Year
Total suitable area (x10 km )
3 2
51.5
51.0
50.5
50.0
49.5
49.0
SSP1-2.6
SSP2-4.5
SSP5-8.5
Baseline 2020
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
∼
RF model performance and methodological
considerations
Acanthurus
= =
Acanthurus=
=
BA
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
Environmental drivers: structural habitat qual-
ity is paramount
Acan-
thurus
A. lineatus
A. triostegus
Acanthurus
Climate vulnerability and species-specic re-
sponses
Acanthurus triostegus
A. xanthopterus
∼
Conservation priorities and management
recommendations
Acanthurus
Acanthurus
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
Limitations and future directions
A. lineatus
<
∼
∼
Acan-
thurus
==
∼
Funding
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
Conicts of interest
Data availability
Ethics statement
Marine and Fishery Sciences 39 (4): xxx-xxx (2026)
=
Perante: Random Forest habitat suitability of Acanthurus in the Philippines
