Sustainable Aquatic Research

Sediment and Water Analysis In Tinorian River, Iloilo, Philippines: Basis For Understanding The River’s Health and Quality

Sun, 31 Aug 2025 00:00:00 +0300

The Tinori-an River is located in the 4th district of Iloilo, specifically in the municipalities of Barotac Nuevo and Anilao. The study aimed to assess the sediment conditions of the river. For site selection, 12 sampling sites were selected within the river and 15 for the ponds. The Total Organic Matter (TOM) and Moisture were determined using the loss-on-ignition (LOI) technique, and grain size was assessed using wet and dry sieving. For water parameters, a multiparameter water meter was used. Results showed that the highest TOM was 12.60% in Pond A. The highest moisture was 62.83% in Pond L. High sand-silt fractions were present in all sampling sites. Water parameters showed that the water was basic and low-fair DO concentrations for both sites. For salinity, upstream was considered freshwater and the other three sites were brackishwater. Temperature was constant in all the study sites. The water was mostly turbid in all sampling sites. The results indicated high TOM and moisture in all sites, which could be traced to slow water movement and the shallowing of the river due to fisheries and anthropogenic activities. The water parameters recorded showed that the river needs attention in areas where DO was less than 5 mg/L. The current study provided baseline data on the health and condition of the Tinori-an River, and the contributing factors to this should be known to have a scientific-based approach to managing the river.

Population parameters of African Carp, Labeo victorianus (Cyprinidae) in River Kuja- Migori, Kenya

Elijah Kembenya, Albert Getabu, James Njiru, Robert Omondi — Sun, 31 Aug 2025 00:00:00 +0300

Labeo victorianus is one of the fish species capable of sustaining commercial riverine fishing in the Lake Victoria basin. The present study was conducted to determine the growth, mortality rate, exploitation rate and recruitment pattern of Labeo victorianus in River Kuja-Migori, Kenya. Fish specimens were collected from January to December 2021 (12 months) using an electrofisher from five sampling stations along the River Kuja-Migori. The total length and total weight of fish samples were measured in centimeters and grams, respectively. Growth parameters, fishing mortality and natural mortality were determined using length frequency data. Electronic length frequency analysis (ELEFAN) software in Fish Stock Assessment Tools (FiSAT II) program was used to analyze data. Natural mortality (M), fishing mortality (F) and total mortality (Z) coefficients were 0.91 yr^-1_,0.65 yr^-1 and 1.56 yr^-1, respectively. The exploitation rate was estimated at 0.42 yr^-1. The asymptotic length (L_∞) was 36.89 cm TL. The instantaneous growth rate (K) was 0.31 yr^-1. There were two recruitment peaks where major recruitment occurred from March to June while a minor recruitment took place between September and November. Results revealed that L. victorianus exhibits a short lifespan of approximately 6 years. The present study contributes significantly to the development of management advice for the riverine fishery of L. victorianus.

Effects of replacing dietary black soldier fly larvae (BSFL) meal with fishmeal (FM) in diets for rabbitfish (Siganus sutor) reared in brackish water intertidal earthen ponds

Douglas Okemwa, Charles Ngugi, David Mirera — Sun, 31 Aug 2025 00:00:00 +0300

The effects of replacing dietary fishmeal (FM) with black soldier fly larvae (BSFL) meal in rabbitfish (Siganus sutor) diets were evaluated over 90 days in intertidal earthen ponds at Kibokoni, Kilifi Creek. A total of 240 fish were assigned to a completely randomized design with four dietary treatments; each replicated three times. Fish were reared in hapa cages (1 m × 1 m × 1 m) with 1 mm mesh. Four diet treatments were formulated: (T1- 100 % BSFL, T2 – 75 % fish meal and 25 % BSFL, T3 – 50 % fish meal and 50 % BSFL, T4 – control commercial feed. Fish were stocked at a density of 20 fish/m^-3 and fed twice daily at 5% of their body weight. The experimental fish had an initial mean weight of 11.64 ± 0.97 g and a mean length of 9.12 ± 0.14 cm. Final mean weight gain of the fish ranged from 22.75 ± 3.89 g in T2 (lowest) to 32.3 ± 4.05 g in T1 (highest). Feed conversion ratio (FCR) did not differ significantly among the diets (P > 0.05), while survival rate (SR) was highest in T2 (93.3 ± 4.73%) and lowest in T1 (71.1 ± 9.18%). The study provides information that will guide farming of rabbitfish in intertidal earthen ponds, and a possible replacement of fish meal with black soldier fly larvae. Further research on optimal stocking densities is strongly recommended.

Quantifying Post-Harvest Fish Losses in Central Kenya: Implications for Small-Scale Aquaculture Sustainability

Sun, 31 Aug 2025 00:00:00 +0300

Post-harvest fish losses (PHLs) significantly hinder the growth and sustainability of Kenya's aquaculture sector, contributing to economic losses and reduced food security. This study aimed to quantify transit-related fish losses, identify contributing factors, and assess the effectiveness of storage and refrigeration practices among small-scale aquaculture farmers in Central Kenya. A cross-sectional survey was conducted between September and October 2023, involving 227 fish farmers from Kirinyaga, Nyeri, and Meru counties. Data were collected using structured questionnaires and analyzed using descriptive and inferential statistics, including one-way analysis of variance (ANOVA) and chi-square tests. The findings revealed that tilapia was the most cultivated species, predominantly in polyculture systems with African catfish. Kirinyaga County had the highest adoption of polyculture practices (58%) compared to Nyeri (24%) and Meru (16.3%). Despite relatively high fish production, Meru County experienced the most significant post-harvest losses, with an average of 7.0 kg lost per farmer, representing 37% of total production. The high losses in Meru were associated with inadequate refrigeration during transit, with 81% of farmers not using any cooling methods, compared to 56% in Kirinyaga and 51% in Nyeri. Transportation times also contributed to losses, with Meru reporting the longest average transport duration (3 hours, 23 minutes). The study recommends investing in affordable and accessible refrigeration technologies, such as solar-powered ice makers and insulated containers, alongside improving transportation efficiency. The findings provide valuable insights for policymakers, development agencies, and stakeholders in the fisheries sector to develop targeted interventions that enhance post-harvest practices, reduce losses, and strengthen the aquaculture value chain. These efforts align with Sustainable Development Goals 2 (Zero Hunger) and 12 (Responsible Consumption and Production) by promoting food security and reducing food losses in the aquaculture sector.

Unlocking Aquaculture Potential in the Kenya’s Arid and Semi-Arid Lands for Food Security and Economic Growth

Sun, 31 Aug 2025 00:00:00 +0300

This review explores the untapped aquaculture potential in Kenya’s arid and semi-arid lands (ASALs), highlighting the region’s underutilized aquatic resources, including rivers, lakes, and dams. Despite Kenya’s substantial water resources relative to top aquaculture producers like Egypt, aquaculture development in ASALs remains minimal, even though these regions cover 89% of the country. The study assesses ASAL water resource suitability for aquaculture, identifies key challenges, and proposes actionable solutions, drawing lessons from Egypt’s successful aquaculture sector. A narrative literature review synthesizing high-quality scientific and grey literature was conducted. Findings reveal that ASALs possess significant aquaculture potential due to their favorable climate for species like Nile tilapia and African catfish, permanent rivers such as the Tana and Athi, and large reservoirs like the Seven Forks Dams. However, challenges such as water-level fluctuations, pollution, wildlife interference, stakeholder conflicts, and financial constraints hinder aquaculture development. The study highlights policy frameworks, financing models, and best practices from Egypt that Kenya could adopt to strengthen its aquaculture sector in the ASALs. It underscores the importance of integrated water management, stakeholder collaboration, and investment in capacity-building initiatives. Innovative approaches such as cage and pond aquaculture, supported by policies and infrastructure, are crucial for unlocking aquaculture’s transformative potential in Kenya’s food systems and rural economies. This review offers valuable insights for policymakers, researchers, and investors to advance aquaculture as a sustainable, scalable solution for economic growth and food security.

When Will the Debate About the Origin of Life End?

Erkan Can, Brian Austin — Sun, 31 Aug 2025 00:00:00 +0300

The origin of life remains one of the most complex and persistent questions in science, philosophy and theology. Despite major advancements in molecular biology, chemistry and planetary sciences, current scientific theories, such as abiogenesis, the RNA world and panspermia, have not yet provided a comprehensive explanation for how life actually began on Earth. In contrast, religious texts, including the Qur’an, the Bible and the Torah, present creation narratives grounded in divine intention, often referencing the role of water and clay in the formation of living beings. These insights, while not methodical in scientific terms, offer foundational perspectives that can inspire further inquiry.

This paper explores the scientific, theological and philosophical dimensions of the origin of life debate, emphasizing that empirical research and metaphysical belief need not be in conflict. Instead, they may be viewed as complementary frameworks: science seeks to explain the mechanism, whereas theology explores the purpose. Also, the discussion reflects on the potential implications of fully uncovering life’s origins — from ethical considerations to the future creation of synthetic life, especially when combined with artificial intelligence.

Ultimately, uncovering life’s beginnings may require cross-disciplinary approaches and the humility to accept epistemological limits. As aquatic environments are essential to life and dominate both the Earth’s surface and the human body, their study is crucial. Continued exploration, supported by emerging technologies, holds promise for revealing the mechanisms behind this fundamental mystery.