Croatian Journal of Fisheries Feed

An overview of the breeding and larval rearing techniques of pearl oyster Pinctada maxima

Sat, 19 Sep 2026 00:00:00 GMT

Pinctada maxima is a pearl oyster species in the Pinctada genus that produces some of the world’s highest-value pearls. In past decades, the pearl culture industry relied heavily on wild stocks of this species for pearl production. To reduce the exploitation of wild populations while simultaneously supporting industry expansion and ensuring sustainable pearl culture, proper broodstock management, breeding techniques, and larval rearing practices are essential. Although information on the breeding techniques and larval rearing practices of Pinctada maxima is relatively abundant, it has not been systematically compiled or organised. Therefore, this review summarises and discusses information reported in previous studies on the breeding techniques and larval rearing practices of Pinctada maxima. The breeding section covers early broodstock selection, intensive broodstock conditioning, previously reported breeding techniques, and egg incubation. The larval rearing section includes larval feeding and nutrition, comparisons of food rations and stocking densities, water quality parameters, and larval settlement, with particular emphasis on the types of spat collectors used. In addition, this review highlights existing knowledge gaps that warrant further investigation.

Dynamic modeling analysis of oxygen transfer mechanism and water quality dynamics in recirculating aquaculture systems

Sat, 19 Sep 2026 00:00:00 GMT

Dissolved oxygen is an important indicator in intensive shrimp farming systems. This study aims to analyze the dynamics of oxygen transfer and identify water quality parameters that influence oxygen production levels in shrimp farming using the Recirculating Aquaculture System (RAS) with a dynamic system model approach. The study was conducted in six ponds in Pekalongan, Indonesia, during the RAS operational cycle. The water quality parameters observed were pH, temperature, dissolved oxygen (DO), and salinity, while oxygen transfer rates were analyzed using the standard oxygen transfer rate approach. Data analysis was carried out using statistical tests and dynamic system model analysis. The results showed that oxygen production levels in the RAS ponds ranged from 1.684 to 3.652 mg O₂/L/hour, with the highest value being 3.195 ± 0.15 mg O₂/L/hour (pond 2). Salinity had the strongest correlation with oxygen transfer rate (r = 0.857; p < 0.01), indicating its dominant influence on oxygen diffusion control through water viscosity and paddle aerator performance. PCA. Model simulation results indicated synchronization between paddle aerator rotation speed, water circulation hydrodynamics, and water quality, forming a positive feedback loop that increases the rate of oxygen diffusion in the pond. Conversely, reduced aeration leads to oxygen deficits and water quality fluctuations. Ecological engineering design, hydrodynamic optimization, and aeration management are fundamental factors in the operational cycle of RAS ponds.

Fishponds as Indicators of Freshwater Aquaculture in the Medieval and Early Modern Croatia: A Preliminary Historical Survey

Sat, 19 Sep 2026 00:00:00 GMT

Freshwater aquaculture in Europe has a history spanning over 1,000 years, with its development primarily based on pond culture of common carp. During the Middle Ages, monastic orders and the aristocracy played a key role in the construction and operation of fishponds, as well as in the continuity and dissemination of pond management and husbandry practices. The history of freshwater aquaculture in the territory of present-day Croatia has not been systematically studied, and key aspects, including its origins, spatial distribution, social actors, purposes, management and husbandry practices, and cultured species, remain insufficiently explored. This paper draws on a broad range of historical sources, including archival, statistical, and normative materials, to identify the temporal and spatial distribution of fishponds. Fishponds are used as indicators and are analysed through an interdisciplinary approach incorporating archaeozoological evidence in order to reconstruct the development of freshwater aquaculture in Croatia during the medieval and early modern periods. The results indicate that fishponds can be traced back to at least the 11th century, with ecclesiastical institutions representing the earliest social groups involved in their construction and ownership, followed by the nobility. During the Middle Ages, fish production in fishponds primarily served to meet the dietary needs of the Church and the nobility, while in the early modern period, indications of market-oriented production began to emerge. Data on management and husbandry practices are scarce, but they allow for a partial reconstruction of production and organisational patterns. Information on cultured fish species is also limited; however, the most frequently mentioned species include common carp, northern pike, tench and crucian carp. The main limitation of this preliminary study lies in its reliance on general administrative and legal documents, and the lack of systematic analysis of archival materials related to noble families, monastic orders and other ecclesiastical institutions, highlighting the need for further research based on a wider range of sources.

Efficacy of Gracilaria verrucosa extract baths against Trichodina sp. in comet goldfish Carassius auratus

Sat, 19 Sep 2026 00:00:00 GMT

Trichodina sp. is a major ectoparasite affecting Carassius auratus, reducing its aesthetic and market value. This study evaluated the efficacy of Gracilaria verrucosa aqueous extract against Trichodina sp., its impact on fish survival, and the effective dosage. The experiment was conducted using a Completely Randomized Design (CRD) with four treatment groups: K (methylene blue, 0.6 mL/L), P1 (G. verrucosa extract, 10 mL/L), P2 (G. verrucosa extract, 15 mL/L), and P3 (G. verrucosa extract, 20 mL/L), each with three replications. Observations included clinical signs, behavior, parasite prevalence and intensity, time to parasite death, fish survival, and water quality. Infected fish showed excess mucus, scale loss, pale gills, and behavioral changes. Treatment P3 significantly reduced parasite intensity to 2.93 individuals/fish, caused parasite death within approximately 8.5 minutes, and resulted in 100% survival. Parasite lysis was observed in treatments K, P2, and P3. Water quality remained within suitable ranges, with temperature at 26.5–27.9°C, pH 7–8.1, and dissolved oxygen 4.8–5.8 mg/L. These findings suggest that G. verrucosa aqueous extract at 20 mL/L is effective against Trichodina sp. and safe for comet fish.

Type of tide pool as a dominant factor over tidal influence on intertidal fish assemblages in a subtropical island

Sat, 19 Sep 2026 00:00:00 GMT

Tide pools are dynamic intertidal habitats that host specialized fish communities adapted to extreme and fluctuating environmental conditions. This study investigates how tidal cycles influence the diversity and abundance of ichthyofauna in natural and artificial tide pools along the coast of Gran Canaria, Canary Islands. Ten pools (five of each type) were sampled during both high and low tides over a two-month period. Fish species were identified and quantified using visual census techniques, and the data were analyzed using multivariate statistics. Results revealed that, while species richness remained relatively stable across tidal stages, fish abundance was generally higher during low tide (largely due to the increased presence of juvenile individuals). Furthermore, clear differences in community structure were found between natural and artificial pools: artificial pools supported greater fish abundance, whereas natural pools hosted a higher proportion of native, specialized species such as gobies and blennies. These findings highlight the ecological role of tide pools as both nursery and refuge areas and emphasize the importance of considering habitat type and tidal dynamics when assessing coastal biodiversity in subtropical marine ecosystems.

Drifting Nets as a Tool to Achieve Fish Management and Conservation Purposes in the Lower Danube River

Fri, 29 May 2026 00:00:00 GMT

Drift trammel netting is a traditional method for commercial fish catches in the Danube River, especially along the Bulgarian stretch. Potentially, non-commercial or endangered fish species may be caught as bycatch, but no official statistics exist. Recently, freshwater fish populations, including commercial species, have declined. In light of these facts, the study aims to examine recent quantitative fish catches from drift netting in the Lower Danube from a conservation point of view. During the early summer of 2024, 54 transects with drifting trammel nets were performed at two sampling sites on the Lower Danube (Bulgaria). The fishing gear and methodology used were similar to those in commercial fishing. 18 fish species were captured, including one sturgeon species. 9 are under protection in the NATURA 2000 network, and 15 are mentioned in at least one regulatory document. On this basis and for better assessment and conservation, bycatch and discards should be officially registered, and quotas should be considered. As additional output, the presence of Pontic shemaya was confirmed in a new NATURA 2000 site, BG0000530. Thus, it should be included in this site accordingly, since it is the most suitable for its monitoring.

The Role of Mangrove Density in Marine Debris Trapping: A Case Study of Baros Coast, Yogyakarta, Indonesia

Fri, 29 May 2026 00:00:00 GMT

The increase in plastic production has led to a significant accumulation of plastic debris in the environment, particularly in coastal and marine ecosystems. This study aims to characterize the composition and quantify the abundance of marine debris, identify specific plastic polymers, and assess the statistical relationship between mangrove density and marine debris accumulation. Marine debris samples were collected at six sites, divided between the west and east sides of the mangrove ecosystem. The results showed that on the west side, Site 1 had the highest abundance of marine debris (1.2 items/m2), whereas on the east side, Site 3 recorded the highest abundance (0.88 items/m2). The most dominant types of marine debris were thin plastic, packaging, and glass, with a total weight of approximately 434 g at Site 3 on the west side. Analysis of plastic debris showed that polypropylene (PP) dominated on the west side at about 44.44%, while polyethylene (PE) dominated on the east side at about 55.56%. The density of mangroves, especially Avicennia sp., plays a vital role in trapping marine debris through their respiratory roots. A higher amount of marine debris was identified on the west side, which corresponds with higher mangrove density. PCA analysis showed a strong positive correlation between mangrove density, specifically the respiratory roots of Avicennia sp., and marine debris accumulation, identifying these roots as the primary factor influencing debris trapping.

Monitoring the Microbial Prevalence in Farmed Trout Species from an Aquaculture Facility in Kosovo

Fri, 29 May 2026 00:00:00 GMT

The primary objective of this research was to evaluate and quantify the presence of mesophilic bacteria on the skin and within the muscle tissue of farmed rainbow trout. Fish specimens were obtained during the summer from a cold-water fish breeding facility in the Istog region of the Republic of Kosovo. A limited number of fish samples were collected under sterile conditions, reflecting the exploratory scope of this study and constraints in sample availability. Most samples were identified as Oncorhynchus mykiss (rainbow trout), while a smaller proportion corresponded to Oncorhynchus mykiss (golden rainbow trout). The microbiological analysis of the samples was conducted utilizing ISO standard methods for analysing mesophilic bacteria, Escherichia coli, Enterobacteriaceae, coliforms, and Enterococcus faecalis. Results revealed higher contamination on the skin surface compared to muscle tissue, with consistent levels across both trout species. Although differences between tissues were observed, they did not reach statistical significance (p > 0.05), likely due to the limited sample size. Variations among samples indicated the influence of handling practices and environmental factors on microbial presence. The analysis showed that coliforms accounted for 37.13% of microbial presence, followed by other mesophilic bacteria at 35.14% and E. faecalis at 26.92%, with minimal presence of E. coli and Enterobacteriaceae. These findings underscore the importance of further research into external factors affecting microbial growth in aquaculture environments and suggest the need for systematic monitoring and control measures to enhance hygiene standards in fish farming operations.

New Distributional Records of the Endemic Moroccan Blenny Salariopsis Atlantica (Doadrio, Perea & Yahyaoui, 2011)

Fri, 29 May 2026 00:00:00 GMT

Within Northern Africa, Morocco is distinguished by its remarkable diversity of freshwater fish species. This diversity is characterised by a high level of endemism, which is largely due to the country’s unique geographical location and the complexity of its hydrographic network. Salariopsis atlantica (Doadrio, Perea & Yahyaoui, 2011) is an endangered (EN) Moroccan endemic species, historically confined to the Sebou Basin, where it is known from only a few locations. This study reports new populations of the Moroccan blenny further upstream on the Ouargha River, notably at Ghdir Hamma, as well as downstream from Asfalou Reservoir. This expands the species’ known range, which is a key to promoting its conservation. These newly discovered populations are reported from habitats heavily impacted by increasing anthropogenic pressures and invasive alien species. This highlights the need for targeted conservation strategies integrating local threat management, habitat restoration, and exotic species control to ensure the sustainability of this rare species.

Production Performance and Economic aspects of Soft-Shell Crab Scylla spp. Culture in RAS Vertical Crab Boxes with Herbal Applications

Fri, 29 May 2026 00:00:00 GMT

Mud crabs (Scylla spp.) are being cultured in vertical crab boxes using a recirculating aquaculture system. One approach to accelerate and increase the frequency of mud crab molting is to provide plants containing the molting hormone ecdysteroid through feed. This research aims to analyze the production and business performance of soft-shelled crab culture in vertical crab boxes fed diets supplemented with purslane Portulaca oleracea, mulberry Morus alba, and spinach Amaranthus hybridus. Purslane was given to mud crabs at doses of 0 (control), 40, 50, and 60 g/kg, while mulberry was given at doses of 0, 30, 40, and 50 g/kg, and spinach was given at 60 g/kg of feed compared to autotomy and control treatments. Purslane and mulberry, related to the molting percentage and business performance in this mangrove crab culture, were 60 and 50 g/kg of feed, respectively. Purslane and mulberry improved the molting percentage and business performance of mangrove crab culture, although they did not compete with the autotomy treatment. This research contributes to the development of productive, efficient, environmentally friendly, and sustainable soft-shell crab culture by using herbal ingredients to increase the molting percentage.

Spatial Variability in Growth and Condition of Nile Tilapia Oreochromis Niloticus Linked to Pollution Gradients in the Nile River, Egypt

Tue, 17 Mar 2026 00:00:00 GMT

This study investigated spatial variations in growth, condition factor, age, and longevity of Oreochromis niloticus populations along a pollution gradient in the Nile River, Aswan, Egypt. We compared a reference site (Ferial, Site I) with two polluted sites: El-Sail Drain (Site II) and Kom Ombo (Site III). Water and fish samples were collected monthly from January to December 2021 to analyze physicochemical parameters, heavy metals, age structure, growth, and condition factor. The results revealed significant spatial disparities. Fish from Site I exhibited the highest growth potential, with an asymptotic length (L∞) of 27.22 cm, a growth coefficient (K) of 0.17 year−1, and a maximum age of 13.5 years. In contrast, populations from Site II and Site III showed reduced growth (L∞ = 25.46 and 24.52 cm, respectively), higher K values (0.19 and 0.24 year−1, respectively), and shorter lifespans (11.9 and 9.2 years, respectively). Although the growth performance index (Ø) was similar among sites, annual length increments and condition factors were significantly lower at the polluted sites. These findings demonstrate that environmental degradation, primarily from industrial and domestic wastewater, adversely affects the somatic growth and physiological conditions of O. niloticus, highlighting the urgent need for enhanced pollution control and management strategies in the Nile River.

Sustainability Assessment of Coral Reef Ecosystem in Panjang Island, Jepara, Central Java

Tue, 17 Mar 2026 00:00:00 GMT

Panjang Island, Jepara, is a conservation area in the northern part of Jepara Regency, Central Java, where the local community’s economy relies on capture fisheries and tourism. However, human activities and environmental changes have degraded the coral reef ecosystem, threatening the island’s sustainability and local livelihoods. This study aimed to assess the sustainability status of Panjang Island across various dimensions in response to these significant pressures. A descriptive quantitative method was employed. Observations of ecological variables, such as coral cover and recruitment, were conducted using the line-intercept transect method, while reef fish were surveyed using underwater visual census methods, and biodiversity indices were calculated manually. The social, economic, and institutional dimensions were assessed through interviews and focus group discussions. Although the ecological, institutional, and social dimensions are moderately sustainable, the main finding indicates that the economic dimension remains less sustainable. Enhancing community participation, governance, and capacity-building programmes is essential to support sustainable resource use and protect the island’s ecosystem in the long term. These findings highlight the urgent need for synergistic and holistic management strategies that prioritize the improvement of local economic opportunities. Such an integrated approach is crucial for achieving balanced and genuinely sustainable coral reef management on Panjang Island.

Species-Specific Evidence of Structural Change in Portuguese Fisheries: A 30-Year Analysis of CFP Reform Influence

Tue, 17 Mar 2026 00:00:00 GMT

This study provides the first national, species disaggregated quantitative assessment of structural changes in Portuguese marine fisheries over three decades (1995 – 2024), coinciding with major reforms of the European Union’s Common Fisheries Policy (CFP). Using annual landings data for 47 species, Spearman rank correlation was applied to detect long term monotonic trends between year and landing volume, a non parametric approach robust to non normality, zeros, and outliers. Results reveal a pervasive decline: 26 species (55.3%) exhibited significant negative trends (ρ as low as −0.953, P < 0.001), including commercially important demersals such as European hake and gurnards. Conversely, 9 species (19.1%) showed significant positive trends (e.g. Atlantic mackerel, European sea bass; ρ up to +0.778, P < 0.001), while 12 species (25.5%) remained statistically non significant. These patterns are directionally consistent with CFP objectives to reduce fishing mortality and promote selective exploitation, while acknowledging alternative drivers such as climate variability and reporting changes. The findings indicate systemic restructuring of Portuguese fisheries, with widespread reductions in demersal landings and selective increases among pelagic species, reflecting adaptive responses to regulatory and ecological pressures. This work contributes novel species level evidence of long term structural transformation, offering a baseline for future causal analyses using interrupted time series or multivariate approaches. By quantifying monotonic trends across 47 species, the study enhances understanding of policy aligned shifts in fleet behavior and ecosystem exploitation, informing adaptive governance and sustainability strategies under evolving EU fisheries frameworks.

The Relationship of Microplastic Abundance in Green Mussel Perna Viridis and the Waters of Mangkang Beach, Semarang

Tue, 17 Mar 2026 00:00:00 GMT

Plastic, especially microplastics, currently poses a potential threat to water pollution. Microplastics are found not only in water but also in aquatic biota. Green mussels Perna viridis cultivated in Mangkang Wetan coastal waters may be contaminated with microplastics. This research aimed to determine the abundance of microplastics by shape, colour, and polymer type, and to examine the relationship between the abundance of microplastics in the aquatic environment and green mussels P. viridis. Data collection was carried out using a random sampling method to assess the distribution of green mussel cultivation by collecting water samples and green mussels, which were analyzed using quantitative methods. Data analysis was performed using ANOVA and regression analysis. The research identified 4 types of microplastic forms in the waters and 3 in green mussels, with fragment forms dominant in both. Seven colours were found (yellow, green, blue, black, transparent, brown and red), with brown being the dominant colour. Nine types of polymers were identified (polyvinyl chloride, polyethylene terephthalate, polypropylene, low-density polyethylene, high-density polyethylene, nylon, cellulose acetate, polyethersulfone and polystyrene), with polyethylene terephthalate as the dominant polymer. The abundance of microplastics in the waters and green mussels at Station 1 was 6.33 ± 0.45 particles/liter and 4.91 ± 2.32 particles/ind, at Station 2 it was 2.33 ± 0.49 particles/liter and 1.33 ± 0.28 particles/ind, and at Station 3 it was 4.63 ± 0.32 particles/liter and 2.91 ± 1.18 particles/ind. The ANOVA results for microplastic abundance in the waters showed a significance value of 0.00 < 0.05. The ANOVA results for green mussel microplastic abundance showed a significance value of 0.072, which is > 0.05. The regression analysis showed an exponential pattern, with a coefficient of determination (R2) of 0.685.

Changes in the Proportion of Fish Species Caught by Artisanal Fishers in the Croatian Section of the Sava River

Tue, 17 Mar 2026 00:00:00 GMT

The number of artisanal fishers, and consequently their catch, in the Sava River has declined significantly over the past two decades. The average weight of some species has also changed significantly. Therefore, the aim of this paper is to investigate possible changes in the biomass proportion in the catch of the most important taxa during this period. Most of the investigated species showed considerable variation in catch from year to year, but without a clear trend (P > 0.05). The largest fluctuations, with a coefficient of variation (CV) over 90%, were found in Acipenser ruthenus, Cyprinus carpio, Leuciscus aspius and allochthonous species. Esox lucius, Leuciscus idus, Silurus glanis and Sander lucioperca had CVs between 41% and 73%. The smallest variations in the proportion of catch were recorded for Abramis brama and other autochthonous species (the most abundant being Rutilus virgo), with CVs of 37.77% and 33.43%, respectively. These two taxa also showed significant opposite trends (R² = 0.34; P < 0.01) and had a combined average biomass proportion of 67.03%.

Heavy metal concentrations in the muscle tissues and liver of three most commercial fish species from the River Vjosa – Aoos (Albania-Greece)

Wed, 31 Dec 2025 00:00:00 GMT

The concentrations of Fe, Mn, Zn, Cu, Pb and Cd in the muscle tissue and liver of chub Squalius platyceps, barbel Barbus prespensis and nase Chondrostoma vardarense were determined. These three species are among the most widely consumed by local people in the wide Vjosa Basin. Prior to this study, no research had been conducted on heavy metal bioaccumulation in the Vjosa River ecosystem. This research also intends to address the potential health risks for the local population consuming fish resources. The fish species were sampled between the Petran and Kelcyra sites during spring and autumn 2024, with analyses conducted on the concentrations of six heavy metals in muscle tissue and liver. Two instrumental techniques were used for these analyses: atomic absorption spectrophotometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). The results were analyzed using SPSS software version 30.

Acute toxicity impact of indoxacarb on gill neuroendocrine system and brain of stinging catfish Heteropneustes fossilis

Wed, 31 Dec 2025 00:00:00 GMT

The recent study aimed to evaluate the impact of acute toxicity of indoxacarb (IDC) on pseudobranchial neurosecretory cells (PNSCs), biochemical assays and histopathological changes in the brain, and accompanying behavioral abnormalities in the air-breathing stinging catfish Heteropneustes fossilis. The 96-hour LC50 of IDC was ascertained at a dose of 0.075 mg/L. Live catfishes were exposed to LC50 dose of IDC for 24, 48, 72 and 96 hrs, and the respective parameters were studied at predetermined intervals. After 96 hrs of exposure to IDC, histopathology of PNSCs demonstrates degenerative changes, reduced neurosecretory material, significantly decreased number of PNSCs along with nucleocytoplasmic (N/C) ratio, as compared to the control group. The exposed fishes displayed detachment of stratum marginale (SM) and stratum opticum (SO), mild necrosis in stratum periventricular (SPV), and compact neuroarchitecture of stratum fibrosum et grisium superficiale (SFGS), stratum griseum centrale (SGC) and stratum album centrale (SAC), whereas degeneration of mononuclear cells and Purkinje cells in the cerebellum was observed. The acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT) activities were significantly decreased, whereas malondialdehyde (MDA) level was significantly increased, as compared to the control group. The total distance traveled, swimming speed, mobility time, absolute turn angle, head: distance traveled, and maximum speed were significantly decreased, whereas immobility time, maximum inactive episode, and time freezing were significantly increased in comparison with the control group. This study concludes that acute toxic concentrations of IDC may cause physiological dysregulation, biochemical changes in brain tissues and mild necrotic changes in PNSCs and neuronal cells in fish, resulting in substantially associated behavioral disturbances.

Reproductive characteristics of mackerel scad Decapterus macarellus (Cuvier, 1833) in northern Philippine waters

Wed, 31 Dec 2025 00:00:00 GMT

Mackerel scad Decapterus macarellus is a highly valuable species in the Philippines municipal and commercial fishing industry, particularly in northern Philippine waters in the Babuyan Channel fishing ground. The study assesses reproductive characteristics, including the sex ratio, catch seasonality, fecundity, gonadosomatic index (GSI), gonad and sexual maturity (Lm and L95), and length range distribution by gear. Samples were collected in the Babuyan Channel fishing ground from April 2018 to March 2020. The results showed that D. macarellus is present throughout the year in the fishing ground, with noted peaks from April to July. An unbalanced sex ratio was found between the females (1:18) and males (1). The mean fecundity was 25,546 eggs. The gonadosomatic index revealed that the spawning season of D. macarellus occurs throughout the year, with an observed prolonged spawning and a notable peak during the northeast monsoon. The length at maturity (Lm) was 14.15 cm, and L95 was 17.60 cm. Of all the fishing gear for catching the species, beach seines catch most of the juveniles. Management options such as establishing additional Marine Protected Areas to support fish populations and productivity of the species, and reducing fishing effort are recommended to protect and conserve the stock.

The effect of the addition of papaya seed flour Carica papaya L. in feed on the immune response and growth performance of whiteleg shrimp Litopenaeus vannamei

Wed, 31 Dec 2025 00:00:00 GMT

The main issues in shrimp farming are disease and high feed prices. To overcome these issues, a safe and inexpensive substance that can improve health and growth is needed. Natural ingredients from plants such as papaya Carica papaya L. are widely available in Pekalongan. This study aimed to determine the effect of papaya seed flour as a substance addition to artificial feed on the immune response and growth performance of whiteleg shrimp. This experimental research employed a completely randomized design (CRD) consisting of five treatments and three replications. The test animals were whiteleg shrimp (PL21) post-larvae, while the test feed was supplemented with papaya seed flour at different doses for each treatment: 0 g.kg−1 feed (A); 1 g.kg−1 feed (B); 3 g.kg−1 feed (C); 5 g.kg−1 feed (D); and 7 g.kg−1 feed (E). The parameters observed included PA (Phagocytic Activity), THC (Total Haemocyte Count), absolute biomass, SGR (Specific Growth Rate), and FCR (Feed Conversion Ratio). Treatment D was identified as the optimal dose, resulting in PA of 65.67%, THC of 48.93 x 106 cells.mL−1, absolute biomass of 6.23 g, SGR of 6.09%.d−1, and FCR of 1.18, with a 100% survival rate. Data analysis confirmed that the treatments had a significant difference (P < 0.05) on all parameters. The results showed that the use of papaya seeds can improve both the health and growth of whiteleg shrimp.

The life and work of Metka Povž (1944–2024), a leading Slovenian ichthyologist

Wed, 31 Dec 2025 00:00:00 GMT

Dr. Metka Povž (1944–2024) was a distinguished Slovenian ichthyologist whose career spanned over five decades, during which she authored more than 500 publications, both scientific and professional. Her work significantly advanced knowledge of freshwater fish in Slovenia and the broader Balkan region, with particular emphasis on species inventories and fish conservation. This paper reviews her major scientific contributions, including her role in protecting endangered native fish species, such as the preservation of pure populations of marble trout Salmo marmoratus, her research on non-native fish species, and her involvement in the protection of freshwater habitats. Her work remains a cornerstone in the field of ichthyology in the region and continues to inspire the ichthyological community.