1 Institute of Environmental Science and Meteorology, University of the Philippines, Diliman, Quezon City, Philippines

2 The Marine Science Institute, University of the Philippines, Diliman, Quezon City, Philippines

3 Department of Chemical Engineering, University of the Philippines, Diliman, Quezon City, Philippines


Marine microplastics are emerging pollutants that impact across levels of marine food chain at a global scale. Its presence was determined on Sardinella lemuru, a commercial pelagic fish that are harvested generally in the Northern Mindanao, consumed locally, and exported worldwide as bottled or canned sardine products.  The stomach contents of 600 sardines were examined visually under a microscope, stained with Rose Bengal, and tested with hot needle technique to identify ingested microplastics. These anthropogenic particles were measured and physically classified into fibers, fragments, and films. Results of this study showed that 85% of S. lemuru were already contaminated with 3.74 ± 3.92 # of microplastics even before being processed into various sardine products. These microplastics ranged from 0.12 to 21.30 mm and 80 % were mostly < 2.5 mm size classes. The dominant microplastics were 97.94 % in the form of fibers while 1.52 % and 0.54 % were respectively classified into fragments and films. Method validation by isolating microplastics from spiked samples (n = 30) with three retrieval attempts showed 100% recovery efficiency. While results from Canonical Correspondence Analysis of ingested microplastic data had no relationship with the standard lengths of the sardine and the masses of ingested food materials at varying size classes, the total number of ingested microplastics from 2014 to 2016  were directly correlated (r2=0.91, p=0.003) with the human population at the landing sites  along the coastline of northern Mindanao.

Graphical Abstract

Susceptibility of Sardinella lemuru to emerging marine microplastic pollution


  • About 80% out of 600 surveyed sardines in Northern Mindanao, Philippines, were susceptible to marine plastic pollution;
  • Microplastics accounted approximately 96% of the ingested marine debris and about 98% existed in the form of fibers;
  • The ingested microplastic density was highly correlated to the size of human population in the sardine landing sites along the coast of Northern Mindanao.


Main Subjects

Letters to Editor

GJESM Journal welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in GJESM should be sent to the editorial office of GJESM within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.
[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.
[3] Letters can be no more than 300 words in length.
[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.
[5] Anonymous letters will not be considered.
[6] Letter writers must include their city and state of residence or work.
[7] Letters will be edited for clarity and length.