Iranian Journal of Fisheries Sciences
Volume:25 Issue: 2, Mar 2026

This study examined the performance of rainbow trout (Oncorhynchus mykiss) farms in the Sistan region of Iran during 2023-2024, using the super-efficiency envelopment analysis technique.  Data were collected through structured questionnaires, and technical efficiency was evaluated using the basic Data Envelopment Analysis (DEA) approach. The findings were then compared with the super-efficiency DEA model. The average technical efficiency was 63.50% (ranging from 0.21 to 1) under the constant return to scale model and 79.35% (ranging from 0.54 to 1) under the variable return to scale model. Additionally, average scale efficiency was 76.1% (ranging from 0.38 to 1). Only 20% of the farms achieved full efficiency, exhibiting significant variations in technical efficiency. The results demonstrated that discrepancies in input consumption management were the primary factor contributing to technical inefficiency. Therefore, optimizing input management is critical for enhancing efficiency in these aquaculture systems.

In the fish feed industry, fishmeal (FM) is highly valuable for its excellent combination of essential amino acids and fatty acids. However, due to its high cost and low availability, researchers are focusing on alternative sustainable plant-based protein sources. However, phytate, a major phosphorus-rich compound in plants, has a chelating effect that significantly reduces the absorption and bioavailability of essential nutrients, leading to nutritional imbalances. Adding phytase enzyme (PHY) in aqua feed improves the digestibility of minerals and reduces their excretion. Therefore, this study assessed the impact of PHY supplementation on hematological indices and mineral digestibility in Catla catla when fed different plant protein-based diets for FM replacement such as Moringa oleifera leaf meal (MOLM), sunflower meal (SFM), canola meal (CM), guar meal (GM). Nine test diets were formulated: a control diet without PHY, and eight experimental diets with PHY added at 250 or 500 FTU/kg. The results revealed that the addition of 500 FTU/kg of PHY to a 50% MOLM significantly enhances the digestibility of minerals like P, Mg, Al, Na, K, Cu, and Zn, when compared to control and other test levels. In terms of blood indices, this supplementation increased the values of RBCs (3.18×106mm-3), Hb (8.68 g/100 ml), PCV (30.07 %) and WBCs (8.20×103mm-3) count as well as serum liver enzymes alanine aminotransferase (0.93 U/L) and aspartate aminotransferase (3.11 U/L). The results indicated that the most effective combination was a diet (T3) containing 50% MOLM and 500 FTU kg-1 PHY, which yielded optimal hematological and mineral profiles. Conclusively, this study shows that PHY-supplemented plant-based fish diets reduce the need for mineral supplements, lowering feed costs and environmental impact.

A 2×3 factorial design was used to assess the effects of dietary copper (Cu) and selenium (Se) on growth, oxidative stress, and immunity in Beluga sturgeon (Huso huso) juveniles fed optimal and high levels of Mintrex® copper and selenomethionine. Six experimental diets were formulated with two Cu levels (10 and 50 mg Cu kg-1) and three Se levels (5, 11, and 55 mg Se kg-1): Cu10Se5, Cu10Se11, Cu10Se55, Cu50Se5, Cu50Se11, and Cu50Se55. Each diet was fed to triplicate groups of 15 fish (initial weight 13.31±0.35 g) for 12 weeks. The fish fed with Cu10Se11 diet exhibited the highest weight gain (1092.2±11.2%), significantly greater than those fed with Cu10Se5 (962.2±17.3%), Cu10Se55 (928.6±33.7%), and Cu50Se55 (721.1±46.6%) diets. The best feed conversion ratio was observed in Cu10Se11 (1.24±0.05), while the lowest value was in Cu50Se55 (1.81±0.16). The protein efficiency ratio was significantly high in Cu10Se11 (1.87±0.02) and low in Cu50Se55 (1.28±0.16). The hepatic Cu and Se concentrations increased dose-dependently, reaching 38.12±2.4 μg g-1 and 11.68±0.8 μg g-1, respectively, in Cu50Se55. The lowest thiobarbituric acid reactive substances (TBARS) value was recorded in Cu10Se11 (5.83±0.56 U mg-1 protein), while the highest was in Cu50Se55 (11.8±0.56 U mg-1 protein). Antioxidant enzyme activities (CAT, GPx, and Cu-Zn SOD) were significantly reduced in Cu50Se55, whereas IgM (46.1±2.65 µg mL⁻¹) and lysozyme (17.7±0.95 U mL-1) values were high in Cu10Se11, but they were markedly suppressed in Cu50Se55 (IgM: 21.4±1.09 µg mL⁻¹; lysozyme: 9.9±0.74 U mL-1). Both IgM and lysozyme values were decreased with excess dietary Cu and Se and were negatively correlated with TBARS. These findings indicate that Cu10Se11, containing 10 mg kg-1Cu and 11 mg kg-1 Se, optimally enhances growth, reduces oxidative stress, and strengthens immunity in Beluga juveniles, while excessive Cu and Se intake impairs antioxidant capacity and immune functions.

The current checklist documents species diversity of the order Carangiformes across major regions of the Northwest Indian Ocean (NIO) including the marine waters of the Persian Gulf, Sea of Oman/Oman Sea, Arabian Sea, Red Sea and the Gulf of Aden. A total of 168 species, belonging to 72 genera and 16 families have been documented. The most diverse family is Carangidae (60 species, 36%), followed by Bothidae (24 species, 14%), Cynoglossidae and Soleidae (each family with 19 species, 11%). During the past decade, only two new valid species Cynoglossus crepida and Cynoglossus glotta have been described from the region. According to the IUCN red list, most of the reported species (110 species, 65%) are classified as least concern (LC). Additionally, 31 species, (18%) are listed as Data Deficient (DD), 23 species (14%) as Not Evaluated (NE), while three species (Trachurus indicus, Trachurus trachurus and Makaira nigricans) as vulnerable (VU). Kajikia audax is asssessed as Near Threatened (NT). Further research and collection efforts will likely reveal more species in this area.

Lycopene is a major carotenoid pigment recognized for its potent antioxidant properties and its role as an essential micronutrient in aquafeeds, contributing to enhanced antioxidant activity, immune response, and feed efficiency. This study evaluated the effects of dietary lycopene supplementation on growth performance, antioxidant capacity, and digestive enzyme activities in the oriental river prawn (Macrobrachium nipponense). A total of 225 prawns with an average initial weight of 1.40±0.07 g were fed five formulated diets containing 0 (control), 50, 100, 150, and 200 mg kg⁻¹ lycopene for 56 days. At the end of the feeding trial, hepatopancreas and intestinal tissues were collected for the analysis of growth performance, antioxidant indicators, and digestive enzyme activities using standard biochemical kits and spectrophotometric methods. The results showed that lycopene supplementation significantly improved growth performance and total antioxidant capacity, while the levels of superoxide dismutase, catalase, and malondialdehyde were significantly reduced compared with the control group (p<0.05). Digestive enzyme activities were also influenced by lycopene levels, with the highest activities observed in prawns fed 200 mg kg⁻¹ lycopene and the lowest in the control group (p<0.05). Overall, these findings suggest that a dietary inclusion of 200 mg kg⁻¹ lycopene is optimal for enhancing antioxidant status and digestive enzyme activity in M. nipponense juveniles.

Proliferative kidney disease (PKD), caused by Tetracapsuloides bryosalmonae, is a major challenge in rainbow trout (Oncorhynchus mykiss) aquaculture. To better understand the host response at the molecular level, eight microarray datasets from erythrocytes of healthy and infected fish (GSE198859) were analyzed to identify differentially expressed genes (DEGs) using the GEO2R tool. The results revealed that upregulated genes such as SNRPE, miR-301b, TNFRSF10B, Bckdha, and Aqp1 are associated with RNA processing, post-transcriptional regulation, osmoregulation, energy metabolism, and apoptosis, highlighting their essential roles in compensatory responses to kidney damage. Conversely, downregulated genes including Degs1, Flt1, BATF3, and RALY suggested suppression of angiogenesis, inhibition of dendritic cell responses, disruption of immune signaling, and impairment of lipid metabolism and RNA processing, which may represent part of the parasite’s strategy to evade host immunity. GO analysis showed significant enrichment in cellular components such as the nucleus, nucleosome, plasma membrane, exosomes, and extracellular regions. In parallel, molecular functions related to kinase activity and protein binding emphasized the importance of signaling and intercellular communication during infection. Overall, these findings suggest that the rainbow trout response to PKD involves a combination of activated defense pathways and simultaneous suppression of some critical immune components by the parasite, which contributes to its survival. The identified genes and pathways may serve as potential molecular markers and support future efforts in selective breeding to improve resistance against PKD.

The production of aquatic animals and plants in an aquaponic system helps conserve water and soil while aligning with environmental sustainability and food security initiatives, as it eliminates the need for agricultural fertilizers and pesticides. This study investigates the quality of red hybrid tilapia (Oreochromis sp.) and various medicinal plants, including peppermint (Mentha piperita), common mint (Mentha sativa), oregano (Mentha pulegium), green and purple basil (Ocimum basilicum), miniature basil (Ocimum basilicum minimum), and fennel (Foeniculum vulgare), cultivated in an aquaponic system. In this system, which operated at water salinity levels of 1.1 ± 0.1 ppt, fish production reached 53.3 kg/m³ over a seven-month breeding period. The plant production ranged from 0.64 to 2.30 kg/m² monthly. The analyzed plants had iron levels ranging from 12.3 to 34.1 mg/100g, calcium levels between 1.3 and 24.6 mg/100g, and potassium levels from 3.3 to 30 mg/100g. Proline and chlorophyll concentrations were measured at 0.44-3.70 mg/g and 2.49-5.10 mg/g, respectively. Nitrite concentrations were found to be between 0.9 and 2.8 mg/kg, while nitrate levels ranged from 56.6 to 805.3 mg/kg of fresh plant weight, both significantly lower than permissible thresholds. The total essential oil percentage in the examined medicinal plants ranged from 0.11% to 0.82%, indicating the presence of beneficial compounds. Overall, aquaponic production can play a significant role in contributing to the development of healthy food products in both the agriculture and aquaculture sectors.

Zooplankton are among the most important microscopic animals in aquatic ecosystems, playing a crucial role in maintaining water quality and serving as a vital link in the food chain. Water quality parameters play a crucial role in regulating the abundance and diversity of zooplankton. This study was conducted over a period of three months at three different locations within the Ranganathittu Bird Sanctuary (RBS), Karnataka, India, to assess the diversity and abundance of zooplankton. Key physicochemical parameters including water and atmospheric temperature, electrical conductivity, pH, turbidity, total dissolved solids, carbon dioxide, biological oxygen demand, dissolved oxygen, phosphate, and nitrite were analyzed. The zooplankton community was represented by four major taxa: Copepoda, Cladocera, Rotifera, and Ostracoda, comprising a total of 34 species. The analysis revealed a total of 34 zooplankton species across all sampling sites. Among these, Cladocera emerged as the dominant and most species-rich taxon, represented by 14 species, followed by Copepoda (10 species), Rotifera (8 species), and Ostracoda (2 species). The present study contributes to understanding zooplankton diversity and abundance in relation to physicochemical parameters of surface water across the islands of Ranganathittu Bird Sanctuary (RBS), highlighting the influence of environmental factors on community structure.

This study investigated the effects of whey powder (WP), used as a nutrient medium, on the biomass production, biochemical composition, and pigment content of Haematococcus pluvialis and Scenedesmus sp. The experimental design was set up with four groups and all groups had three replicates.  The control group (C) contained only Bold Basal Medium with 3-fold nitrogen and vitamins (3N-BBM+V) without WP.  The second experimental group was formulated as 3N-BBM+V with 5 g L⁻¹ WP (W5), the third group as 3N-BBM+V with 10 g L⁻¹ WP (W10), and the fourth group as 3N-BBM+V with 15 g L⁻¹ WP (W15). In this study, the highest mean biomass was obtained as 0.88 g L⁻¹ for H. pluvialis (WP10) and 0.45 g L⁻¹ for Scenedesmus sp. (WP15). The maximum total lipid productivities of H. pluvialis and Scenedesmus sp.  were recorded as 43% (w/w, dry weight) in the WP5 group and 66% (w/w, dry weight) in the WP10 group, respectively. Under mixotrophic conditions, the highest protein contents were obtained in WP10 for H. pluvialis (20.94 mg mL-1) and in WP15 for Scenedesmus sp. (44.94 mg mL-1). Astaxanthin, carotenoid and phycocyanin productivity of H. pluvialis and Scenedesmus sp. was highly determined under mixotrophic conditions. In conclusion, the present study demonstrates that the supplementation of the culture medium with whey powder significantly enhances both biomass production and biochemical composition. Therefore, whey powder can be recommended as an effective supplementary nutrient source for the cultivation of these microalgae.

The present study documents the first records of the dwarf sperm whale Kogia sima, Owen, 1866 (Cetacea: Kogiidae) from the Persian Gulf, based on the stranding of two specimens occurring in November 2023 and 2024. The specimens were registered, respectively, on Larak and Qeshm Islands, Hormozgan Province, Iran. This report provides morphological characteristics confirming species identification. The recorded strandings occurred approximately one year apart, at sites, within a 50 km range in the northern Strait of Hormuz, Persian Gulf. They provide novel insights into this elusive species' potential seasonal and spatial movements at their presumed westernmost range in the shallow Persian Gulf, restricted by habitat limits considering its normal deep-water distribution.