Habitat model to predict the spatial distribution of Mobula japanica bycatch species in the eastern Pacific

Abstract

Use of the MaxEnt habitat distribution model to predict the potential habitat distribution of Mobula Japanica in Baja California, as well as the possible change on habitat distribution as consequence of the climate change.

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Results
Background
Devil rays have been identified as an important
component of the tropical tuna purse seine
fishery bycatch, particularly in the eastern Pacific
Ocean (Hall and Román, 2013).
Understanding the oceanographic processes
which explain the habitat of Mobuja japanica in
this Ocean is essential to develop practical
solutions for their management and conservation
(Couturier et al. 2012).
Although their vertical and horizontal
movements have been previously studied in Baja
California using tagging data (Croll et al. 2012),
the distribution of their potential habitat and
possible impact of environmental change is
poorly known.
Objective
The objective of this work was to describe the
potential habitat of M. japanica bycatch species
from the tropical tuna purse-seine fishery in Baja
California and evaluate the potential habitat
change under A2 scenario of climate change.
Conclusions
•MaxEnt habitat distribution model provides a good description of the habitat of M. japanica in Baja California.
•Potential habitat of M. japanica is directly related with productive and warm waters.
•Global warming could affect to the distribution of this species, with loss of habitat inside of the Gulf as
consequence of the increase in temperatures and decrease of the primary production.
•The inclusion of independent data (i.e. tagging) or other environmental variables could improve the performance
and predictive value of the models.
•This work could contribute to the conservation of this species in areas of special interest and to reduce their
interaction with the purse-seiner fishery.
Acknowledgements
References
1. Couturier L et al. (2012) Biology, ecology and conservation of the Mobulidae
Journal of fish biology 80:1075-1119
2. Croll DA, Newton KM, Weng K, Galván-Magaña F, Sullivan JO, Dewar H (2012)
Movement and habitat use by the spine-tail devil ray in the Eastern Pacific
Ocean Marine ecology progress series 465:193-200
3. Etnoyer P, Canny D, Mate BR, Morgan LE, Ortega-Ortiz JG, Nichols WJ (2006)
Sea-surface temperature gradients across blue whale and sea turtle foraging
trajectories off the Baja California Peninsula, Mexico Deep Sea Research Part
II: Topical Studies in Oceanography 53:340-358
4. Fiedler PC, Philbrick V, Chavez FP (1991) Oceanic upwelling and productivity in
the eastern tropical Pacific Limnology and Oceanography 36:1834-1850
5. Franklin J, Miller JA (2009) Mapping species distributions. Spatial inference
and prediction Cambridge University Press Cambridge:340 pp.
6. Hall M, Roman M (2013) Bycatch and non-tuna catch in the tropical tuna
purse seine fisheries of the world FAO fisheries and aquaculture technical
paper 568
The observer data analyzed was collected by IATTC observer programs. The first author
(NLO) is funded by a Basque Government Postdoctoral grant (Spain) and conduct her
investigation at IATTC.
Habitat model to predict the spatial distribution of
Mobula japanica bycatch species in the eastern Pacific
Nerea Lezama-Ochoa1,2; Martin Hall2; Hilario Murua1; Kelly Newton3; Don Croll3
1 AZTI Marine Research Division (Spain); 2 Inter-American Tropical Tuna Commission (IATTC); 3 University of California in Santa Cruz (UCSC)
PP
PP
Years: 2005-2015
Fishery: Tropical tuna purse-seiner fishery
observer program
Occurrences: 31 (IATTC database)
Pseudo-Absences: 10000 (randomly selected)
Habitat model: MaxEnt (Franklin, 2009)
Oceanographic variables
- Sea Surface Temperature
- Depth
- Primary production
Validation : k-fold cross validation (General model)
- Training data (80%): fit the model
- Testing data (20%): evaluation of the model
Evaluation : Area under the Curve (AUC)
> 0.8 Good performance
Material & Method
Present & Future (2100)
Potential present habitat
Difference Future-Present
Possible movement of M. japanica
during Summer from inside (June)
of the Gulf to the Pacific coast
(September):
•following the zooplankton
distribution (Croll et a. 2012)
•increase of temperature inside
during August
Warm waters
(around 24ºC)
Low depths
(< 1000 meters depth)
High concentrations
(> 800 mgC·m-²·/day)
AUC: 0.91
Study area: Baja California
Fiedler et al. 1991
60.5%
33.9%
5.6%
% Contribution
Habitat loss: 7%
Sea Surface Temperature
Habitat gain: 2%
Gulf of Ulloa: potential habitat also for turtles
and marine mammals (Etnoyer et al. 2016)
Gulf of
Ulloa