Research involving an MCU College of Arts and Sciences faculty member compared floating marine litter in protected and non-protected coastal areas in La Union—and found no statistically significant difference between the two sites.
Does giving a coastal area protected status mean there will be less floating litter in its waters?
A study involving Mr. Jean-Matthew B. Bate of the Manila Central University College of Arts and Sciences – Biology Department examined that question by comparing floating marine litter in two neighboring coastal areas in San Fernando City, La Union.
Researchers conducted sampling in the Lingsat Marine Protected Area (LMPA) and nearby Dalumpinas Oeste, a non-protected area.
Plastic was the predominant type of litter collected at both sites. Although researchers recorded more individual pieces of litter in the protected area, statistical analysis found no significant difference in the amount or density of floating litter between the two locations.
Published in CLEAN – Soil, Air, Water, the findings suggest that marine protection status alone may not necessarily translate to lower levels of floating debris and point to the need to examine how litter-management measures are being implemented in the area.
Comparing protected and non-protected waters
Marine protected areas are established to help conserve marine ecosystems and the resources they support.
But floating debris does not necessarily remain within the boundaries where it originates.
The researchers wanted to examine whether the amount, type, and density of floating meso- and macro-litter differed between a protected coastal area and a nearby location without the same protected status.
Meso-litter refers to relatively small pieces of debris, while macro-litter consists of larger pieces that are easier to see and collect.
To investigate, the researchers conducted an intensive three-day sampling at the Lingsat Marine Protected Area and Dalumpinas Oeste.
But instead of relying on sophisticated or expensive equipment, they used a modified prototype of a Low-Tech Aquatic Debris Instrument (LADI) to collect floating debris from the water.
The approach provided a practical way to compare marine litter between the two locations.
Plastic dominated at both sites
One finding was consistent across the two sampling areas: plastic was the predominant type of floating litter.
Researchers recorded 604 pieces of litter in LMPA, where the collected debris was dominated by macro-litter.
In comparison, 277 pieces were collected in Dalumpinas Oeste.
At first glance, that difference may appear substantial. But when the researchers analyzed the data, the difference in the number of pieces between the two locations was not statistically significant.
The same was true when they compared the density of floating litter.
Despite one site being protected and the other not, the study found no statistically significant difference in floating litter density between the two nearby coastal areas.
That finding raises an important question about how floating marine debris moves through coastal environments—and what protection means when pollution can travel beyond geographic boundaries.
A low-tech way to look at a large problem
Another notable part of the research was the instrument used to collect the debris.
The researchers developed a modified prototype of the Low-Tech Aquatic Debris Instrument, or LADI, based on an instrument proposed by the Civic Laboratory for Environmental Action and Research.
Its use demonstrates how relatively accessible equipment can contribute to environmental monitoring and the collection of local evidence about marine pollution.
This could be particularly useful for future studies and monitoring efforts in coastal areas where access to more sophisticated equipment may be limited.
The research also provides localized data from San Fernando City, helping build a clearer picture of the types and distribution of floating litter affecting its coastal waters.
What does this mean for marine protection?
The findings do not mean that marine protected areas are ineffective.
Instead, they highlight a more specific challenge: protected status does not necessarily prevent floating debris from entering or accumulating in an area.
Marine litter can be influenced by factors beyond the boundaries of a protected area, making waste management, monitoring, and surrounding human activities important parts of the broader picture.
For the Lingsat Marine Protected Area, the researchers believe the findings warrant another look at the measures currently being used to address the issue.
“These results now suggest an urgent need to review the current measures taken by LMPA,” the researchers stated.
The study provides local evidence that can contribute to decisions about marine-litter monitoring and coastal management while offering a baseline for future comparisons.
Where does the research go from here?
The three-day study provides a snapshot of floating marine litter at the two locations rather than a complete picture of how debris changes throughout the year.
Further monitoring could help researchers understand how litter levels vary over longer periods and under changing environmental conditions.
Similar studies could also be conducted in other protected and non-protected coastal areas to determine whether the patterns observed in San Fernando City are seen elsewhere.
For now, the findings underscore an important poaint for coastal management: drawing a boundary around a marine ecosystem cannot, by itself, keep floating litter outside it.
Understanding where that litter comes from, how it moves, and how effectively it is being managed remains an important part of protecting coastal environments.
The study, “Distribution of Floating Marine Meso- and Macro-Litter Using an Improvised Low-Technology Aquatic Debris Instrument,” was published in CLEAN – Soil, Air, Water, Volume 54, Issue 2, Article e70124.
Research Information
MCU Researcher: Mr. Jean-Matthew B. Bate
College: MCU College of Arts and Sciences – Biology
Journal: CLEAN – Soil, Air, Water
Published: February 17, 2026
Volume: 54, Issue 2
Article: e70124
DOI: 10.1002/clen.70124
Full Research Article: https://onlinelibrary.wiley.com/doi/full/10.1002/clen.70124
