“Sardines are cheap and easily purchased by most Filipinos. During pandemic and disasters, canned sardines are made available as source of protein. Restoration of the sardine fisheries stock and rebuilding of the sardine population should be a major goal of the Philippines, but research is needed about the fish and its ecology,” Dr. Ephrime B. Metillo, MSU-IIT.
Sardinella lemuru, commonly known as Bali sardine or Tamban, is a culinary treasure for Filipino households, gracing tables with its diverse products–canned, dried and fresh. Its versatility–being the main ingredient to diverse dishes and affordability makes it a staple, and often associated with the term “ayuda” (relief goods) during time of needs. Thus, the staggering plummet by 75% of its population, due to relentless overfishing, rampant illegal fishing, and the insidious effects of ocean pollution and warming, led to rising concerns not just to the manufacturers and consumers, but also to the whole aquatic ecosystem.
Zamboanga peninsula is the biggest manufacturer of canned sardines in the Philippines, earning the name of being the “Sardines Capital”. Thus, in an attempt to address the declining sardine population, the annual three-month ban (December to February) fishing policy has been implemented. However, it sparks debates among the local fishermen: is the seasonal ban a necessity or a constraint? To some extent, the ban ensures adult females can lay eggs in a year, but the concern is the massive fishing after the ban placing at risk young adults not reaching maturity and become spawners of the following year.
The Sardine Food Web
A team of scientists of Dr. Ephrime B. Metillo of Mindanao State University – Iligan Institute of Technology; Dr Wilfredo L. Campos of University of the Philippines Visayas; Dr. Maria Rio Abdon-Naguit of Jose Rizal Memorial State University–also the University President, is conducting a three-year research program entitled “Attaining Sustainability in the Fisheries for Sardines and other Small Pelagic Fish off the Zamboanga Peninsula”. Dr Metillo leads the Project 2, “Feeding Ecology of Sardines in the Northern Zamboanga Peninsula”. The entire program aims to produce knowledge that is essential to guide into a sustainable sardine management.
The Project 2 has three major objectives: first is to create a sardine food web; second is to understand predation and competition components of the food web; and third, to determine changes of feeding interactions between season and among sampling locations.
Now, you might wonder, what is the importance of understanding the food web of the animals? Will it benefit, us, human beings, in any way? The answer, is a big YES!
Dr. Metillo, MSU-IIT, in an interview, stated that “Understanding the feeding ecology of our local sardines is critically important. Feeding ecology is fundamental to understanding how ecosystems function, how species interact, and how energy and nutrients flow through natural systems. It provides critical insights for addressing global challenges such as climate change, biodiversity loss, and sustainable resource management. By studying feeding ecology, scientists can better predict fish reproduction, and mitigate the impacts of human activities on ecosystems”.
The statement of Dr. Metillo, corresponds to that of the US National Oceanic and Atmospheric Administration’s (NOAA) assertion that, it is important that the food web of aquatic creatures would be studied and understood, as the simplest changes–e.g., removing a top predator or adding nutrients, can change the whole ecosystem.
Food web models contain comprehensive information of the interactions within an ecosystem. This can then be a scientific basis for the policy makers to ensure that decisions are made with a holistic understanding of the ecological dynamics, leading to a more sustainable outcome. Thus, it is imperative that a study focusing around development of food web models to be credible.
Advanced Methods and Technologies
The three-year project of Dr. Metillo does not play around when it comes to providing extensive and reliable data.
The methods used were the classic stomach content analysis, and Carbon (C), Nitrogen (N), and Oxygen (O) stable isotopes to analyze the chemical components of what the food animals consume. According to research the use of stable isotopes has been widely adapted by scientists for decades now as it revolutionized the study of long-term assimilated food and animal movement.
The project also generates data that are then incorporated in the Ecopath with Ecosim (EwE) software together with fisheries data from other Program components. The EwE is a computer tool used to create a model of sardine food web and study interactions and impact of fisheries within an ecosystem, with the data gathered throughout the project. According to Ecopath with Ecosim webpage, the tool is used by researchers and policymakers around the world, with over 8,000 users in more than 170 countries. This wide recognition and adoption are a testament to the reliability and effectiveness of the software.
Moreover, the project is funded and supported by the Marine Resources Research Division, Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development (PCAARRD), and the Department of Science and Technology (DOST). The support facilitated the utilization of advanced technologies, significantly enhancing the credibility of the project’s data.
The set of equipment includes microphotography, elemental analyzers, and Infra-Red Mass Spectrometry (IRMS). Such equipment analyze diet and track nutrient pathways. Some of the most sophisticated equipment for this research are housed at Northwestern University, Evanston, Illinois, USA, where the stable isotope analysis is conducted.
But Why Study the Sardines?
Aside from being a commonly consumed food of Filipino family, with 71% eats sardine products at least five times a month. The sardine species is also a foundation to the marine biodiversity, given that it is the common food of pricey predators.
“At present, the sardine fisheries alone and the canning and bottling industry are worth PhP 10.45 Billion. If we take into account the value of tuna fisheries (tuna feeds on sardines), the value of sardines becomes astronomical,” Dr. Metillo, MSU-IIT, stated.
According to Bureau of Fisheries and Aquatic Resources (BFAR), the sardines also make up 15% to the total catch of fish, 48,000 workers are employed in commercial fisheries, and is the most accessible source of protein of the Filipinos. Given this numbers, the study and topic of sardines is imperative. Very recently, canned sardines and other sardine products can now be part of Philippine export.
Discoveries!
When asked regarding the results of the project, Dr. Metillo of MSU-IIT, stated that “So far, we found that the main food of sardines include zooplankton, mainly copepods (also poorly studied and understood), and some phytoplankton. We found that Carbon, Nitrogen and Oxygen stable isotope analysis technique is very useful in the study. We also found a few microplastics in the stomach contents of sardines.”
The limited studies conducted on sardine prey populations (copepods), might be one of the major reasons of the decreasing population. Climate change could be disrupting the feeding grounds causing for the sardines to naturally migrate to where copepods and zooplankton thrives.
Furthermore, the discovery of microplastics in the stomach contains of the sardines is alarming. Human being consumption can lead to risk of digestive issues, chemical exposure, and other health issues. While the exact set of information and impact may be still studied, it is evident that the existence of such problem is due to human activities.
What should be done, then?
Bridging the gap of theory and practice has long been a persistent challenge within the academe. However, through partnerships, this project aims to not be constrained within the journal world.
“The present project has signed a Memorandum of Understanding (MOU) with the Southern Philippines Fishing Industry (SOPHIL). The organization is our partner so that our findings will be inputted to the industry in order to achieve sustainable development of the sardine-based economy in the country,” Dr. Metillo, MSU-IIT, revealed.
Furthermore, the scientists of the project asserts that scientific studies should advocate the use of Layman’s term in order to be more accessible to the public. In the case of sardine related projects, the target audience also includes the fisherfolks, whose expertise is not rooted in analyzing research papers, but in braving the unpredictable tides and listening to the whispers of the wind.
Photos by Dr Ephrime Metillo
- Sardines (Sardinella lemuru) in the stomach of yellow fin tuna.
2. Dr Metillo at Northwestern University Laboratory
3. Copepod zooplankton
4. Sardine foodweb
5. Sardines (Sardinella lemuru)
