Fisheries Journal, 16 .
, 52-58 .
http://doi.
org/10.
29303/jp.
THE EFFECT OF SEA SURFACE TEMPERATURE ON SMALL PELAGIC
FISH CATCHES IN WPP 573
Pengaruh Suhu Permukaan Laut terhadap Hasil Tangkapan Ikan Pelagis Kecil di WPP 573 Gilang Maulana.
Raymundus Putra Situmorang*.
Yosy Gustasya Defense University of the Republic of Indonesia IPSC Sentul Area.
Sukahati.
Citeureup District.
Bogor Regency.
West Java *Corresponding author: raymundusp@gmail.
(Received October 29th 2025.
Accepted January 3rd 2.
ABSTRACT Sea surface temperature (SST) is a key oceanographic parameter influencing the distribution and abundance of small pelagic fish in tropical waters.
This study aims to analyze the effect of SST on small pelagic fish catches in Fisheries Management Area (FMA) 573.
Catch data were obtained from the Fisheries Resource Center of Indonesia (FRCI) for the 2015Ae2021 period, while SST data were derived from Aqua MODIS satellite imagery with 4 km resolution, processed using Seadas 7.
4 software.
simple linear regression was applied to examine the relationship between SST and fish catches.
The results indicate a negative relationship, where each 1 AC increase in SST tends to reduce catches by approximately 35 thousand tons.
The coefficient of determination (RA) of 0.
531 shows that 53.
1% of the catch variability is explained by SST, while the remaining is influenced by other factors such as primary productivity .
, upwelling intensity, global climate phenomena (ENSO.
IOD), and fishing pressure.
These findings highlight SST as an important indicator for predicting fishing seasons in FMA 573 and emphasize the need to integrate satellite-based oceanographic data into Ecosystem-Based Fisheries Management (EBFM) to ensure sustainable fisheries in Indonesian tropical Keywords: Sea Surface Temperature.
Small Pelagic Fish.
FMA 573.
Regression Analysis.
Sustainable Fisheries ABSTRAK Suhu permukaan laut (SPL) merupakan salah satu parameter oseanografi penting yang memengaruhi distribusi serta kelimpahan ikan pelagis kecil pada perairan tropis.
Penelitian ini bertujuan untuk menganalisis pengaruh SPL terhadap hasil tangkapan ikan pelagis kecil pada Wilayah Pengelolaan Perikanan (WPP) 573.
Data hasil tangkapan diperoleh dari Fisheries Resource Center of Indonesia (FRCI) periode 2015Ae2021, sedangkan data SPL berasal dari citra satelit Aqua MODIS dengan resolusi spasial 4 km yang diolah menggunakan perangkat lunak Seadas 7.
Analisis regresi linier sederhana digunakan untuk menguji hubungan antara SPL dan hasil tangkapan.
Hasil penelitian menunjukkan adanya hubungan negatif, di mana setiap kenaikan 1 AC SPL cenderung menurunkan hasil tangkapan sekitar 35 ribu ton.
Koefisien determinasi (RA) sebesar 0,531 mengindikasikan bahwa 53,1% variasi e-ISSN : 2622-1934, p-ISSN : 2302-6049 Fisheries Journal, 16 .
, 52-58.
http://doi.
org/10.
29303/jp.
Maulana et al.
hasil tangkapan dijelaskan oleh SPL, sedangkan sisanya dipengaruhi faktor lain meliputi produktivitas primer .
, intensitas upwelling, fenomena iklim global (ENSO.
IOD), dan tekanan Temuan ini menegaskan pentingnya SPL sebagai salah satu indikator musim penangkapan di WPP 573 dan perlunya integrasi data oseanografi berbasis satelit dalam EcosystemBased Fisheries Management (EBFM) untuk mewujudkan perikanan berkelanjutan.
Kata Kunci: Suhu Permukaan Laut.
Ikan Pelagis Kecil.
WPP 573.
Regresi Linier.
Perikanan Berkelanjutan INTRODUCTION Fisheries Management Area (WPP) 573 is one of the important regions in the eastern Indian Ocean of Indonesia that possesses considerable potential for pelagic fish resources.
Fishing activities in this area are dominated by small pelagic fish such as lemuru (Sardinella sp.
), tongkol (Euthynnus affini.
, and layang (Decapterus spp.
Environmental factors such as sea surface temperature (SST), salinity, currents, and chlorophyll-a are important components in determining capture fisheries productivity (Susanto et al.
, 2001.
Sartimbul et al.
, 2.
Sea surface temperature plays a fundamental role in the distribution and abundance of pelagic An increase in SST causes stratification of the water column, which inhibits the upward transport of nutrients from deeper layers, thereby reducing plankton availability and affecting the marine food chain (Pauly & Zeller, 2.
Conversely, a decrease in SST is generally followed by an increase in primary productivity due to the occurrence of seasonal upwelling processes (Kunarso et al.
, 2.
Changes in sea temperature are also closely associated with global phenomena such as the El NiyoAeSouthern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).
During El Niyo phases or positive IOD events, sea temperatures tend to increase and lead to reduced productivity, whereas during La Niya phases or negative IOD events, temperatures decrease and productivity increases (Sartimbul et al.
, 2010.
Susanto et al.
, 2.
This pattern influences the distribution of small pelagic fish in WPP 573, which is a major current pathway of the eastern Indian Ocean (La Demi et al.
, 2.
In addition to oceanographic factors, socio-economic pressures also affect catch yields.
Factors such as rising fuel prices, changes in operational costs, and fisheries policies can reduce fishing frequency (Halim & Hidayat, 2.
Therefore, the relationship between SST and catch yields needs to be examined integratively by considering both biophysical and socio-economic factors of fisheries (Pitcher et al.
, 2009.
Tupamahu et al.
, 2.
This study aims to examine the effect of sea surface temperature on the catch of small pelagic fish in WPP 573 by utilizing satellite data and catch data over a seven-year period.
The results are expected to support ecosystem-based capture fisheries management in tropical Indonesian waters (Zainuddin et al.
, 2.
METHODS
This study uses secondary data obtained from two main sources, namely data on small pelagic fish catches and sea surface temperature (SST) data.
Catch data were obtained from the Fisheries Resource Center of Indonesia (FRCI) in the form of annual data for the period 2015Ae2021 for Fisheries Management Area (WPP) 573 with coordinates 6AAe15A S and 104AAe124A E.
These data were used to represent fluctuations in small pelagic fish catches in the study area.
Meanwhile.
SST data were obtained from Aqua MODIS satellite imagery with a spatial resolution of 4 km.
The imagery used consists of monthly climatological data for the year 2024, which are freely accessible through the official MODIS Ocean Color website .
Image processing was carried out using SeaDAS 7.
4 software with the following steps: .
image cropping to match the study area, namely the waters of WPP 573, .
extraction of SST values from the cropped images, .
exporting data in Mask Pixels format containing e-ISSN : 2622-1934, p-ISSN : 2302-6049 Fisheries Journal, 16 .
, 52-58.
http://doi.
org/10.
29303/jp.
Maulana et al.
latitude, longitude, and SST values at each point, and .
further processing using Microsoft Excel to organize the data and save them in .
txt format for analysis readiness (Nurhayati et al.
, 2.
After both types of data were obtained, processing was carried out using a simple linear regression method to analyze the relationship between SST .
ndependent variabl.
and small pelagic fish catches .
ependent variabl.
This regression analysis produced a mathematical equation used to explain the direction and magnitude of the effect of SST on catch yields.
In addition, the coefficient of determination (RA) was calculated to determine the extent to which variations in catch yields can be explained by changes in sea temperature.
RESULTS AND DISCUSSION
Table 1.
Sea Surface Temperature Data and Small Pelagic Fish Catches in WPP 573 .
5Ae Year Temperature (AC) Catch (Ton.
Regression Prediction (To.
159,215 179,176 87,510 92,736 136,674 166,913 155,757 175,671 224,664 185,294
157,843
135,774
146,032
140,530
The Influence of Sea Surface Temperature and Catch Results Linear regression analysis between sea surface temperature (SST) and small pelagic fish catches in WPP 573 in the 2015Ae2021 period produced the following equation:
Y=Oe53.
532yX 1,683,447.
10Y = -53.
532 \times X 1,683,447.
10Y=Oe53.
532yX 1,683,447.
With y representing the catch yield .
and x representing sea surface temperature (AC).
A negative regression coefficient indicates an inverse relationship between SST and catch yield.
Thus, an increase in SST of 1AC implies a decrease in catch yield of approximately 53,532 tons.
The coefficient of determination (RA) of 0.
638 further indicates that 63.
8% of the variation in catch yield can be explained by changes in SST, while the remainder is influenced by other factors (Sativa et al.
, 2.
e-ISSN : 2622-1934, p-ISSN : 2302-6049 Fisheries Journal, 16 .
, 52-58.
http://doi.
org/10.
29303/jp.
Maulana et al.
These results indicate that SST is one of the dominant environmental factors that subsequently influences the availability of small pelagic fish in a given aquatic region.
Small pelagic fish are sensitive to temperature fluctuations due to their close role within the planktonic food web.
Lower temperature conditions generally support higher primary productivity, thereby increasing fish stocks.
Conversely, higher temperatures can cause water column stratification, resulting in reduced nutrient availability at the surface and decreased phytoplankton productivity, which serves as the primary food source for pelagic fish.
High sea surface temperatures cause stratification of the water column, which inhibits vertical mixing processes and reduces nutrient availability in the euphotic layer.
This condition leads to a drastic decline in phytoplankton, which serves as the primary food source for zooplankton and small pelagic fish (Kunarso et al.
, 2.
Conversely, when sea temperatures are relatively lower, the surface water layer becomes richer in nutrients and promotes increased primary productivity.
This was observed in 2019, when an average sea temperature of 28.
04AC was associated with the highest catch yield .
,664 In general, the trend in catch yield shows a decline in 2016 when sea surface temperature reached its highest point .
77AC), with the lowest catch yield of 87,510 tons.
Conversely, in 2019, with relatively lower temperatures .
04AC), catch yields increased significantly to 224,664 tons.
This demonstrates an indication that lower temperature conditions tend to support the productivity of small pelagic fisheries, presumably due to increased water fertility .
rimary productivit.
resulting from oceanographic dynamics.
External Dynamics Affecting Catch Results While the SPL has a significant influence, a number of other external factors contribute to catch fluctuations in WPP 573, including:
Global Climate Phenomena (ENSO and IOD) WPP 573 is located in waters that are strongly influenced by global climate phenomena such as the El NiyoAeSouthern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).
In years characterized by El Niyo anomalies or positive IOD events, sea surface temperatures in western Indonesian waters generally increase due to reduced upwelling and diminished transport of cold water masses from the These conditions lead to a decline in aquatic productivity and small pelagic fish catches.
Conversely, during La Niya periods or negative IOD phases, upwelling activity tends to intensify, e-ISSN : 2622-1934, p-ISSN : 2302-6049 Fisheries Journal, 16 .
, 52-58.
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Maulana et al.
transporting nutrient-rich water masses to the surface and increasing small pelagic fish stocks (Nursan et al.
, 2.
This correlation was clearly observed in 2016, when a strong El Niyo event caused a global hightemperature anomaly, accompanied by a decline in catch yield to only 87,510 tons.
A similar pattern was also reported by Kunarso et al.
, who found that increased sea temperatures due to El Niyo resulted in reduced pelagic fish catches in the Flores Sea and Bone Bay.
This phenomenon illustrates the close relationship between ocean dynamics and fluctuations in fish catch yields (Tupamahu et al.
Upwelling and Primary Productivity In addition to being influenced by global climate anomalies, seasonal upwelling dynamics in the eastern Indian Ocean constitute an important factor in determining the abundance of small pelagic fish in WPP 573.
Strong upwelling increases chlorophyll-a concentrations, enriching waters with nutrients that support the planktonic food web.
Conversely, weak upwelling reduces primary productivity, even when temperature does not increase significantly.
According to Susanto et al.
, seasonal upwelling in the southern waters of Java and Sumatra occurs between July and September, coinciding with the east monsoon season.
During this period, catch yields tend to increase because the distribution of small pelagic fish becomes more concentrated in nutrient-rich waters.
Therefore, annual catch data in WPP 573 reflect the cumulative effects of upwelling strength and regional sea temperature conditions.
Fishing Pressure (Fishing Effor.
In addition to oceanographic conditions, catch yields are also influenced by fishing intensity .
ishing effor.
and socio-economic factors.
An increase in the number of fishing fleets, the use of nonselective fishing gear, and weak enforcement can trigger overfishing, which reduces small pelagic fish stocks even when environmental conditions are favorable (Pauly & Zeller, 2.
During 2016Ae2018, data from the Ministry of Marine Affairs and Fisheries indicated a significant increase in the number of small vessels operating in WPP 573 waters, potentially intensifying pressure on pelagic fish stocks.
In addition, fluctuations in fuel prices and export restriction policies strongly influence fishersAo behavior.
When operational costs increase, fishers tend to reduce fishing frequency, which subsequently affects the decline in total annual catch yields (Halim & Hidayat, 2.
Research by Marni et al.
shows that imbalances between fishing effort and resource availability lead to coastal ecosystem degradation.
Therefore, adaptive ecosystem-based policies are required to maintain the sustainability of fish stocks (Pitcher et al.
, 2.
Ecological Conditions and Fish Migration Patterns The results of this study confirm that sea surface temperature can be used as a primary indicator in predicting the potential catch of small pelagic fish in tropical Indonesian waters.
For more adaptive fisheries management, satellite-derived information on sea temperature and chlorophyll-a should be integrated into the Ecosystem-Based Fisheries Management (EBFM) system, so that the use of remote sensing data such as Aqua MODIS and Sentinel-3 imagery can assist in monitoring sea surface temperature conditions and predicting potential fishing grounds (Zainuddin et al.
, 2.
This approach enables decision-making based on ecosystem conditions rather than solely on catch yields.
Furthermore, enhancing fishersAo capacity to utilize digital technologies based on satellite imagery .
uch as Aqua MODIS or Copernicus Sentinel-.
can help them determine potential fishing locations and optimal fishing times.
Thus, the sustainability of small pelagic fish resources in WPP 573 can be maintained through synergy between marine environmental monitoring, regulation of fishing effort, and coastal community empowerment.
The findings of this study indicate that sea surface temperature is a critical indicator in determining fluctuations in small pelagic fish catch yields.
Therefore, fisheries management in WPP 573 needs to integrate satellite-based oceanographic information, such as sea surface temperature and chlorophyll-a data, into fishing season planning.
The Ecosystem-Based Fisheries Management e-ISSN : 2622-1934, p-ISSN : 2302-6049 Fisheries Journal, 16 .
, 52-58.
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Maulana et al.
(EBFM) approach is highly relevant to be implemented so that management focuses not only on catch yields but also on the supporting ecosystem conditions.
In addition, improving fishersAo capacity in utilizing information technology, such as satellite dataAebased applications, can assist in identifying potential fishing areas.
In this way, fisheries productivity can be maintained without increasing the risk of overexploitation.
CONCLUSION
This study demonstrates that sea surface temperature has a significant influence on small pelagic fish catch yields in WPP 573.
Regression analysis results indicate a negative relationship, in which increasing sea temperature tends to reduce catch yields.
The coefficient of determination (RA = 0.
indicates that approximately 53.
1% of the variation in catch yields can be explained by variations in sea surface temperature, while the remainder is influenced by other factors such as chlorophyll-a availability, upwelling intensity, global climate phenomena (ENSO.
IOD), as well as fishing pressure and fisheries policy dynamics.
These findings confirm that sea surface temperature can be used as an important indicator in predicting the potential catch of small pelagic fish in tropical Indonesian waters.
Therefore, fisheries management in WPP 573 should integrate satellite-based oceanographic information with ecosystembased fishing strategies such as Ecosystem-Based Fisheries Management.
In addition, enhancing fishersAo capacity to utilize oceanographic information technology is also key to supporting fisheries sustainability while preserving small pelagic fish resources in the region.
ACKNOWLEDGMENTS
The authors express their gratitude to all parties who have assisted in facilitating this research, from the planning stage, data collection, to the writing of this journal article.
REFERENCE