Evidence and patterns of tuna spawning inside a large no-take Marine Protected Area

Research confirms that the Phoenix Islands Protected Area (PIPA), one of the world's largest marine protected areas, serves as a critical spawning ground for skipjack, bigeye, and yellowfin tunas. This discovery underscores PIPA's ecological significance in sustaining tuna populations, which are vital to Kiribati's economy through foreign fishing licenses. The study, conducted from 2015 to 2017, employed larval sampling and a biological-physical model to map spawning locations. Findings revealed that skipjack larvae were more abundant near PIPA's northeast corner, while bigeye and yellowfin larvae showed lower but even distributions. Genetic barcoding verified the presence of these tuna species within PIPA. Model simulations indicated that most larvae collected in 2015 originated inside PIPA, whereas stronger currents in 2016 transported more larvae beyond its boundaries. Despite varying environmental conditions due to ENSO states, PIPA consistently supported tuna spawning, highlighting its role as a protected breeding habitat.

Hernández, C. M., Witting, J., Willis, C., Thorrold, S. R., Llopiz, J. K., & Rotjan, R. D. (2019). Evidence and patterns of tuna spawning inside a large no-take Marine Protected Area. Scientific Reports, 9(1). https://doi.org/10.1038/s41598-019-47161-0