Saud M. Al. Jufaili

Sex ratio skew in wild fish populations may indicate environmental stress; however, this remains poorly understood in Omani wadi-endemic killifish. This study investigates sex ratio variation, environmental correlates, sexual dimorphism, and conservation implications in Aphaniops spp. across seven wadi sites in northern Oman. A total of 1417 individuals were collected in spring 2023, while 30 physicochemical variables were recorded over five seasons from spring 2022 to spring 2023. The pooled sex ratio was strongly female-biased (73.4% female; χ² = 310.21, p < 0.001), with six sites deviating significantly from 1:1. Males were longer than females (t = 3.94, p < 0.001). Dissolved potassium was the strongest negative associate of the proportion of males (β = −0.455, OR = 0.635, p < 0.001), followed by turbidity (β = +0.232, p = 0.005) and depth (β = +0.244, p = 0.006); all associations are exploratory and do not establish causation. These findings suggest that dissolved potassium is associated with sex ratio variation in Aphaniops spp., and highlight Wadi Al Amirat as a priority site, five wadis as watch sites, and Wadi Surur as a baseline site (non-significant sex ratio only; not indicative of undisturbed reference conditions) for conservation.

Clinostomum spp. are digenetic trematodes characterized by high genetic diversity and complex life cycles involving three hosts: snails, fish, and birds. These parasites signifi-cantly impact freshwater ecosystems, particularly when infecting fish as the second in-termediate host. Despite their ecological importance, no studies have examined the morpho-molecular characteristics of Clinostomum spp. from freshwater fish species in Oman, limiting our understanding of their life cycles and potential threats to the local aquatic environment. The present study investigated Clinostomum spp. infecting killifish (Aphaniops sp.) from four locations in the Muscat region of the Sultanate of Oman (Al Amirat, Al Khoud, Darsait, and Al Bahayes) using integrated morphological and mo-lecular approaches. Metacercariae were morphologically characterized through organ measurements and molecularly identified using mitochondrial cytochrome c oxidase subunit I (COI) sequences. Morphometric analysis revealed that Clinostomum parasites from Omani freshwater bodies were consistently smaller than the established species C. complanatum and C. marginatum reported from other regions. DNA sequence analysis indicated that the Omani specimens were closely related to, but distinct from, Turkish C. complanatum, suggesting they may represent a potentially novel species or subspecies.

Freshwater ecosystems in arid regions possess extraordinary levels of biodiversity, yet they are subject to unprecedented pressures of climate change and anthropogenic activities. We employed an integrated approach of incorporating species distribution modeling (MaxEnt), habitat suitability modeling, and protected area analysis to assess conservation requirements for two endemic/native killifish ( Aphaniops kruppi and A. stoliczkanus ) in Oman’s freshwater ecosystems. Using MaxEnt with CHELSA bioclimatic variables and topographic indices, we modelled climate change impacts under three shared socio-economic pathways (SSP1–2.6, SSP3–7.0, and SSP5–8.5) spanning 2011–2100. Predictive models demonstrated remarkable accuracy (AUC: 0.974 for A. kruppi , 0.950 for A. stoliczkanus ) revealing unique biogeographical patterns. A. kruppi showed restricted southern distribution dependent on monsoon moisture levels, with mean monthly climate moisture index (Cmi_m; 39.9%), mean diurnal range (Bio2; 18.3%), and sediment transport index (STI; 8.4%) as key variables. The distribution of A. stoliczkanus exhibited a more expansive northern range influenced by winter precipitation patterns, with precipitation of the coldest quarter (Bio19; 31%), the sediment transport index (STI; 20.2%), and the stream power index (SPI; 13.3%) as key drivers. Climate projections revealed high extrapolation risk (85–95%) with anticipated habitat reductions. Habitat suitability assessment of 12 stream sites (Boyce Index: 0.894) revealed unexpected specialization-dominance trade-off, where optimal Aphaniops conditions led to competitive exclusion, resulting in negative correlations between habitat suitability and aquatic biodiversity (Shannon diversity: r = −0.577, p = 0.049). Dissolved oxygen emerged as most critical parameter (mean suitability: 0.771 ± 0.308), with only 25% of sites demonstrating a Highly Suitable status. Spatial analysis revealed significant protection gaps: only 0.31–1.34% of high-suitability habitats and 2.6% of high-density wadis currently protected, requiring 6–24-fold increases to meet conservation targets. Species hybridization necessitates landscape-level conservation maintaining connectivity for gene flow. Results demonstrate that desert aquatic fauna conservation requires integrated strategies addressing climate dependencies, multi-habitat corridor protection, tiered water quality standards, and adaptive management accounting for hybridization zones, providing a replicable model for conservation in water-limited environments.

Post-harvest fish loss (PHFL) is a significant global challenge that negatively impacts livelihoods, economic efficiency, and resource sustainability, particularly in developing nations. In Bangladesh, PHFL in the retail market poses a serious threat to food security, despite the country’s status as a leading global fish producer. This research quantifies the magnitude and drivers of PHFL in Mymensingh, Jamalpur, and Bogura districts of Bangladesh, using a market-based analytical framework. Data were collected from 45 fish retailers through structured interviews, focus group discussions, and key informant interviews from January to March 2025. The Ordinary Least Squares (OLS) regression was applied to quantify physical, quality, and economic losses, and to identify socio-economic and operational determinants of these losses. The results showed an average daily loss of about BDT 282.71 per retailer. Larger transaction volumes and auction delays exacerbate losses, while higher levels of education, an optimal ice-fish ratio, and frequent washing practices significantly reduce losses. Poor cold chain management, unhygienic conditions, and ineffective auction systems accelerate spoilage and deteriorate the fish quality. These findings underscore the critical importance of cold-chain management, vendor training, and efficient auction procedures. Targeted investments in cold storage infrastructure, capacity-building programs for retailers, and streamlined market logistics are recommended to mitigate PHFL, improve fish quality, enhance economic resilience, and advance Bangladesh’s food security. The study provides actionable guidance for policymakers and practitioners seeking integrated solutions to foster more efficient and resilient fish retail systems.

AI enhances aquatic resource management by automating species detection, optimizing feed, forecasting water quality, protecting species interactions, and strengthening the detection of illegal, unreported, and unregulated fishing activities. However, these advancements are inconsistently employed, subject to domain shifts, limited by the availability of labeled data, and poorly benchmarked across operational contexts. Recent developments in technology and applications in fisheries genetics and monitoring, precision aquaculture, management, and sensing infrastructure are summarized in this paper. We studied automated species recognition, genomic trait inference, environmental DNA metabarcoding, acoustic analysis, and trait-based population modeling in fisheries genetics and monitoring. We used digital-twin frameworks for supervised learning in feed optimization, reinforcement learning for water quality control, vision-based welfare monitoring, and harvest forecasting in aquaculture. We explored automatic identification system trajectory analysis for illicit fishing detection, global effort mapping, electronic bycatch monitoring, protected species tracking, and multi-sensor vessel surveillance in fisheries management. Acoustic echogram automation, convolutional neural network-based fish detection, edge-computing architectures, and marine-domain foundation models are foundational developments in sensing infrastructure. Implementation challenges include performance degradation across habitat and seasonal transitions, insufficient standardized multi-region datasets for rare and protected taxa, inadequate incorporation of model uncertainty into management decisions, and structural inequalities in data access and technology adoption among smallholder producers. Standardized multi-region benchmarks with rare-taxa coverage, calibrated uncertainty quantification in assessment and control systems, domain-robust energy-efficient algorithms, and privacy-preserving data partnerships are our priorities. These integrated priorities enable transition from experimental prototypes to a reliable, collaborative infrastructure for sustainable wild capture and farmed aquatic systems.

Fisheries and Aquatic Sciences