Four oxylipin derivatives (1–4) were isolated from a 70% ethanol extract of Eisenia bicyclis, a brown alga. The structures of 1–4 were elucidated by the interpretation with nuclear magnetic resonance (NMR) and mass spectroscopic analysis. Compounds 1–4 were identified as (5Z,8Z,11Z,13E)-15-hydroxyicosa-5,8,11,13-tetraenoic acid, (5Z,8Z,11Z,13E,17Z)-15-hydroxyicosa-5,8,11,13,17-pentaenoic acid, (9Z,11E,15Z)-13-hydroxyoctadeca-6,9,11,15-trienoic acid, and (6Z,9Z,11E,15Z)-13-hydroxyoctadeca-6,9,11,15-tetraenoic acid, respectively. The compounds 1–4 were evaluated for their anti-inflammatory activity on the production of nitric oxide (NO) and cell viability at the concentrate of 100 µg/mL. These results showed that compound 4 exerted moderate inhibitory activity on NO production. Among compounds 1–4, compound 4 was found to be the most abundant, with a concentration of 0.161 ± 0.003 mg/g in the 70% ethanol extract of E. bicyclis.
Age and growth of Nile tilapia (Oreochromis niloticus) from Lake Hayq, Ethiopia, were measured from 8th June 2022 to 7th June 2023. A total of 738 otoliths were taken from the shore, open waters, and river mouths of the lake for macrozone analysis. The otoliths were ground and examined under a dissecting microscope with 7–40× magnification and reflected light microscopy for the distinction of translucent and opaque macrozones. Age determination was done by counting the number of translucent macrozones in the otoliths, taking into account the periods of translucent zone formation. The length of the sampled fishes measured 9.3–32.0 cm in total length (TL), with total weight (TW) measured at 14–495 g, with 87.7% of the length measured ≤ 13 cm TL. The longest life span measured in O. niloticus was 6 years. High correlations exist between otolith length-otolith weight (R2 > 0.88), length-fish length (R2 > 0.92), as well as weight-otolith weight (R2 > 0.81). Weight-otolith weight correlation equal results in asymptotic length regression analyses (R2 > 0.88). The growth parameters calculated using the von Bertalanffy growth equation had an asymptotic length (L∞) of 31 cm, a growth rate (K) of 0.90 per year, with growth performance index (Ø'L) of 2.93. The results are fundamental in building an effective population estimate and fisheries management of O. niloticus in Lake Hayq.
Two newly established Avicennia marina restoration sites along the northwestern Arabian Gulf, including Al-Faw City and Khor Al-Zubair in southern Iraq, were investigated to assess early faunal colonization of restored mangrove habitats. Crabs were sampled from one-year-old mangrove seedlings (mean height ≈ 30 cm). A total of 351 individuals belonging to three species, Opusia indicum, Manningis arabicum, and Nasima dotilliformis, were recorded across ten experimental sites. Crab assemblages differed significantly among sites. At Al-Faw City, O. indicum and M. arabicum dominated, whereas M. arabicum and N. dotilliformis were most abundant at Khor Al-Zubair. Non-parametric analyses revealed significant differences in species abundance among sites (p < 0.05). Diversity indices indicated higher community diversity at Al-Faw City (Shannon–Wiener H' = 0.637; Pielou’s J' = 0.918) compared with Khor Al-Zubair (H' = 0.538; J' = 0.776). Community structure analyses using non-metric multidimensional scaling (non-metric multidimensional scaling [NMDS] stress = 0.12) and permutational multivariate analysis of variance (PERMANOVA) confirmed significant differences between sites (pseudo-F = 62.27, p = 0.007). Opportunistic observations of barnacle aggregations and mudskippers further suggest rapid habitat utilization. Overall, the results demonstrate that newly restored mangrove stands can support rapid, site-specific colonization by benthic fauna, highlighting the capacity of mangrove restoration projects to re-establish functional benthic communities within a short time frame in the northwestern Arabian Gulf.
This study aimed at assessing the small-scale fisheries in Central Gondar, Ethiopia. Information was obtained through focus group discussions (FGDs), questionnaire interviews (QIs), and key informant interviews (KIIs). Across selected sampling sites, a total of 385 fishers were interviewed using pre-tested questionnaire between June 2024 and May 2025. The analysis of data involved the use of descriptive statistics. All respondents were male fishers. Most fishers (78.5%) were between 15 and 46 years old. Educational levels were generally low, with 75.5% of fishers being illiterate; 17.9% had primary education, 3.1% secondary, and only 2.3% attained a diploma or higher degrees. While 45.3% had ≤ 5 years of fishing experience, 1.2% had more than 18 years. Analysis of fisher participation revealed that 92.7% were part-time fishers, whereas 7.3% were occasional fishers. According to fishers, the main fishing activity took place from February to May, and with moderate activity from October to January, but very low activity from June to August, displaying a clear temporal trend. The major fishing gears utilized were cast nets (48.1%), mosquito and hand nets (22.3%), monofilament nets (14.8%), and hooks and lines (7.3%). Analysis of the survey data shows that, 34.0% of fishers caught 1–2 kg of fish per day, 58.4% caught 3–4 kg, and 7.5% caught more than 4 kg. Gutted fish was the main product sold in nearby markets. The survey indicated that 12.5% of fishers earned less than 500 Ethiopian Birr (ETB) per day, while 40.0% reported earnings of 500–800 ETB, 44.4% earned 900–1,200 ETB, but only 3.1% reached 1,300–1,600 ETB per day. The main locally consumed and commercially important fish species were Labeobarbus degeni, Labeobarbus nedgia, Labeobarbus beso, and Labeobarbus intermedius. Generally, the small-scale fishery plays a vital role in ensuring food security and generating income for local communities. Fishers associated the decline of fish populations with illegal and unregulated fishing in the locality, highlighting the urgent need for a joint management strategy that would improve facilities, expand the scope of extension services, and encourage the use of ecologically safe fishing practices.
Gastropods synthesize bioactive compounds as defense mechanisms against environmentally induced oxidative stress. This study evaluated the antioxidant activity, phytochemical content, and bioactive compounds in two gastropod species, Nerita balteata and Cassidula aurisfelis, collected from two distinct mangrove zones: the port-impacted area of Tanjung Api-Api and the conserved area within Berbak Sembilang National Park, South Sumatra, Indonesia. Ethanol maceration was used for extraction, followed by antioxidant testing using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Phytochemical screening employed qualitative tests for alkaloids, flavonoids, saponins, triterpenoids/steroids, and tannins, while gas chromatography–mass (GC–MS) analysis was conducted to identify bioactive compounds. Results showed strong antioxidant activity with IC50 values of 37.188 μg/ml for N. balteata and 33.301 μg/ml for C. aurisfelis. Phytochemical analysis revealed the presence of alkaloids, saponins, and triterpenoids. GC–MS profiling detected compounds such as alcohols, esters, lactones, steroids, and fatty acid derivatives. The findings suggest that gastropods from both polluted and conserved habitats possess strong antioxidative properties and diverse biochemical compounds, which may serve ecological and pharmacological functions. This highlights the need for integrated environmental monitoring and collaborative efforts across disciplines to better understand the impact of pollution-induced oxidative stress in aquatic ecosystems.
