Local Fish Research Articles

Diversity of Fish and Decapod Fry in the Coastal Zone of Amvrakikos Gulf

Amvrakikos Gulf and its surrounding coastal lagoons are of primary importance for the local biodiversity and fishing activities. Fish species inhabited the coastal lagoons based on the seasonal ongoing migration movements of fry and adult fish individuals from the sea towards the lagoons. Information on the early stages of fish and decapod species in the Amvrakikos Gulf is limited only to the planktonic ontogenetic stages and reproduction biology, respectively. The aim of this study was to describe the spatial distribution of fry from commercially important fish and decapod species in the coastal zone of Amvrakikos Gulf. The seasonal appearance of the early stage of the most commercially important fish species caught in the coastal zone of the gulf ranged from one to four seasons, depending on the species. Individuals of all ontogenetic stages (fry, juveniles, and adults) were reported for several species (A. boyeri, A. fasciatus, S. abaster, S. tyfle, and B. ocellaris), indicating that these species may be regarded as residents in the coastal zone, providing habitats for their entire life cycle. The average relative abundance of the species/genera exhibited no differences compared to other Greek brackish waters. The species composition in the Amvrakikos Gulf at 10 cm and above was in agreement with the transitional nature of the area, with permanent and occasional species present. The present study emphasizes the importance of the coastal zone as a nursery habitat for commercially important species.

АНАЛИЗ РЫНКА РЫБНОГО СЫРЬЯ г. КЕМЕРОВО

The purpose of the study is to conduct marketing research of the fish products market in order to determine the needs and preferences of residents of Kemerovo, as well as assess the possibilities of using fish products from local producers of appropriate quality. Objectives: to determine the level of consumption of fish products in the city of Kemerovo; to identify the main producers and the structure of the assortment of the consumer market; to consider the sales volumes of fish products on the market of the city of Kemerovo. To study the analysis of the state of the raw fish market in Kemerovo, eight retail outlets were selec¬ted. Statistical reporting data characterizing the state of the fishery market was collected and analyzed. The conducted review of the fish products market makes it possible to determine the level of consumer preferences of Kemerovo residents from the supply position, to identify the main features of the market, problems and potential for further growth. Analysis of the data obtained shows that the raw fish market in Kemerovo is represented by products from both local producers and fish processors from other regions and countries. More than 55 % of the range of fish products comes from foreign producers and fish pro¬ducts from Russian regions. One of the main problems is the low share of local production in the regional market. To achieve positive results in increasing local fish production, state support is required in the form of subsidies and benefits for local producers of fish and fish products. This will stimulate production growth and ensure affordable prices for consumers with high quality products and reduce dependence on imports. Attracting investors to expand and modernize regional fish farming and production, improving product quality, organizing the production of high-quality fish products that meet quality and safety standards – all this will help increase consumer confidence and create loyalty to local brands.

STRATEGI PENGEMBANGAN EKOWISATA BUKIT BATU, DUSUN SUNGAI LUAR, DESA TIWINGAN BARU, KECAMATAN ARANIO, KABUPATEN BANJAR, PROVINSI KALIMANTAN SELATAN

This research aims to determine what strategies can be taken in managing Bukit Batu Ecotourism. This is because Bukit Batu Ecotourism has considerable potential, including biotic potential such as flora and fauna as well as abiotic potential such as mountains, hills, rivers, forests and lakes which of course have an attraction for tourists. The analytical method used in this research is a qualitative descriptive method. Where this research activity was carried out in natural and uncontrived object conditions, then the data obtained was analyzed using SWOT analysis. the SO strategy in order of priority which is described as follows: (1) Create tourist attractions and attractions that display ecological potential and diversity of flora and fauna such asaviary (giant bird cages), a mini zoo, an aquarium that accommodates local fish species and a miniature Borneo rainforest featuring endemic plant species. (2) Make a viewing tower to enjoy the beautylandscape mountains and lakes as a whole. (3) Empowering the surrounding community in managing Ecotourism such as retribution officers, cleaning officers and security officers. (4) Make plans for the development of facilities and infrastructure based on the most important priorities, such as telecommunication and internet signal booster towers, repair of roads that are still damaged and street lighting. (5) Increase safety warning boards. And (6) Empowerment of BUMDES (Village-Owned Enterprises) with clear work contracts so that they can have an impact on increasing the economy of the surrounding community, such as providing boat rental services, tour guides, bicycle/tent rental and selling souvenirs.

Restoration of an Indigenous aquaculture system can increase reef fish density and fisheries harvest in Hawai‘i

AbstractWhile aquaculture is increasingly considered a globally important source of protein, growing fish for human consumption is not new. Indigenous aquaculture systems, such as loko i‘a (fishponds), were successfully implemented in ancient Hawai‘i and represent a technological advancement designed to sustain a growing human population while maintaining—instead of supplanting—natural ecosystem function in the process of increasing food availability. Biocultural restoration efforts in Hawai‘i, aimed at revitalizing Indigenous stewardship, have included restoration of loko i‘a to sustainably increase the availability of local seafood. While it is clear from historical accounts that loko i‘a can augment fish within estuaries, their role as a nursery ground that supplements surrounding fish populations and fisheries harvest (i.e., providing spillover) remains unstudied in the current literature. This study aimed to test the extent to which loko i‘a restoration can supplement fish populations and fisheries harvest both inside the loko i‘a and in the surrounding waters. A food web model was constructed representing nutrients, phytoplankton, fish, and fisheries in three distinct habitats. The model, set in Kāne‘ohe Bay, O‘ahu, Hawai‘i, revealed that there were interactive effects of the area under loko i‘a management, bay fishing effort, and fish dispersal rates on fish density and fisheries harvest. We found that increasing the area under loko i‘a management not only increased loko i‘a fish density and fisheries harvest but also created the potential to supplement bay fish populations and fisheries harvest under certain scenarios. We also identified a trade‐off whereby at high fish dispersal rates, a larger area under loko i‘a management provided maximal benefits to the bay fish population and fisheries harvest, while at low fish dispersal rates, a smaller area under loko i‘a management was more beneficial to bay fish populations and harvest. As expected, loko i‘a also created a surplus of fish within the pond. Our results support the idea that restoration of Indigenous aquaculture systems can positively impact conservation efforts and food security by increasing local fish availability, through both direct production and supplementation of surrounding fish stocks.

Catalyzing Conservation: An Analysis of Fish Stock Dynamics in a Marine Protected Area before and after Artificial Reef Deployment

The marine ecosystem’s balance is crucial for sustaining biodiversity and supporting fisheries. Marine protected areas have been increasingly used to enhance marine habitats, yet their impact on fish populations remains a topic of debate. This study focuses on a marine protected area in Kitros, Pieria, in Greece, where an artificial reef was constructed, to understand its influence on coastal fish populations. The objectives were to investigate the changes in fish biomass and abundance, comparing the data from periods before and after the construction of an artificial reef. This research compares the data between 2007 and 2008 with the data between 2016 and 2017, collected with bottom trawl surveys strategically executed prior to and after the artificial reef’s installation. Fish species captured were identified, with their lengths and masses measured. The findings indicate an increase in the biomass and abundance of certain fish species after artificial reef deployment, notably the commercially significant Mullus barbatus and Pagellus erythrinus. The artificial reef in Kitros, Pieria, with its surrounding marine protected area appears to have had a positive impact on the local fish populations over the years, suggesting that it can contribute to marine conservation and fishery enhancement. These results underscore the potential of artificial reefs as tools for marine ecosystem management, offering insights for policymakers and environmentalists into coastal resource management.

Implementation of good manufacturing practices (GMP) to improve the quality of smoked fish (Scombercolias)

For several years, fish smoking has been the widely adopted processing method among artisanal fish smokers located along the coastal zones in many parts of West Africa including Ghana. However, several issues pertaining to biochemical and microbiological contaminants still remain, mainly because of the suboptimal, unhygienic fish handling during the processing. To help curtail the problem, we developed and implemented a simple good manufacturing practice (GMP) system for experimentation at two local fish smoking facilities (Facility A, FA; Facility B, FB) to assess the effectiveness for improving the quality of smoked fish. The implementation of GMP did not affect the physical properties of the smoked fish but improved the peroxide value, total volatile base nitrogen, polyaromantic hydrocarbons and histamine levels. The total aerobic counts decreased from 3.96 ± 0.12 cfu/g to 1.52 ± 0.28 cfu/g (FA) or from 4.10 ± 0.2 cfu/g to 1.85 ± 0.85 cfu/g, (FB). The coliforms and Escherichia coli decreased respectively from 1.69 ± 0.12 cfu/g and 1.15 ± 0.21 cfu/g (FA) and from 1.74 ± 0.37 cfu/g and 1.24 ± 0.37 cfu/g, (FB) to below detection (no observed colony) after introducing the single use of potable water, use of smoking oven and fish core temperature of 108.1 ± 7.5 °C and 82.5 ± 3.9 °C, respectively for 2 h, wearing of safety apparels, drying and cooling of smoked fish under nets, and the use of waste disposal bins. The results show that sensitization and training of fish smokers in GMP may be relevant for improving the microbial and overall quality of smoked fish.

Analysis of the food and feeding habit of fresh water carnivorous fish Wallago attu (Bloch & Sneider, 1801) collected from the local fish markets of Agartala, Tripura

Analysis of the food and feeding habit of fresh water carnivorous fish Wallago attu (Bloch & Sneider, 1801) collected from the local fish markets of Agartala, Tripura

Tragedy of the Commons in a Mediterranean MPA: The Case of Gyaros Island Marine Reserve

Gyaros Island (Aegean Sea) is a recently (2019) established MPA in the Mediterranean Sea, allowing spatiotemporal small-scale fishing (SSF) activities with specific access rules. However, due to the inability of the state authorities to establish any fishing permit process, Gyaros MPA initially functioned as a No-Take Zone (NTZ), offering a rare opportunity for scientific monitoring. Significant political pressure by fisher organizations led to the opening of the MPA in June 2022 without any fishing permit restriction. The unprecedented ‘race for fish’ that followed led to a significant deterioration of the MPA status, as confirmed by scientific monitoring before and after the opening. Outcry from national media, based on concerns raised by the scientific community and NGOs, resulted in lifting access to fishing in September 2022, upgrading Gyaros MPA to a full NTZ. This study aimed to assess if and how the MPA functioning was impacted based on a series of experimental fishing trials and questionnaire surveys conducted with local fishers. Although a substantial part of the fishing community’s mindset is embracing MPAs, our results also suggest that the self-interests of a fishers’ minority, along with non-science-based policy by the national authorities, have led to overfishing and deterioration of MPA status.

A Comparative Evaluation of eDNA Metabarcoding Primers in Fish Community Monitoring in the East Lake

East Lake in Wuhan, China, harbors a high number of freshwater fish species of great conservation value, concurrently serving as vital resources for local livelihoods. However, the ecosystem is threatened by an array of anthropogenic activities, thus requiring consistent monitoring of the local fish community to enable more efficacious conservation management. In place of conventional surveying methods, we undertook the first analysis of the fish distribution within East Lake via metabarcoding of environmental DNA (eDNA). The accuracy and efficacy of eDNA metabarcoding rely heavily upon selecting an appropriate primer set for PCR amplification. Given the varying environmental conditions and taxonomic diversity across distinct study systems, it remains a challenge to propose an optimal genetic marker for universal use. Thus, it becomes necessary to select PCR primers suitable for the composition of fish in the East Lake. Here, we evaluated the performance of two primer sets, Mifish-U and Metafish, designed to amplify 12S rRNA barcoding genes in fishes. Our results detected a total of 116 taxonomic units and 51 fish species, with beta diversity analysis indicating significant differences in community structure diversity between the six sampling locations encompassing East Lake. While it was difficult to accurately compare the species-level discriminatory power and amplification bias of the two primers, Mifish outperformed Metafish in terms of taxonomic specificity for fish taxa and reproducibility. These findings will assist with primer selection for eDNA-based fish monitoring and biodiversity conservation in the East Lake and other freshwater ecosystems.

Vulnerability to Climate Change: Adaptation Costs of Artisanal Sea Fishing in Lima Region, Peru

Artisanal fishers and their livelihoods are vulnerable to variable catches caused mainly by climate change. The objective of this study is to assess vulnerability and estimate the costs of adaptation to climate change among artisanal fishers in the Lima region. The method consisted of generating catch loss indices and adaptation measures for artisanal marine fishing based on workshops with local fishers. According to the seawater surface temperature anomalies (SSTA) metric recorded by coastal laboratories of the Peruvian sea, the El Niño phenomenon in the summer of 2017 was classified as strong. We constructed five-catch variation indices (from ‘slight’ to ‘severe’ catch loss variation). The results indicate that in the artisanal fishery, despite there being no species subject to severe variation, there were some, such as flathead mullet (Mugil cephalus), mahi mahi (Coryphaena hippurus), and crab (Platyxanthus orbignyi), with a very high variation index, while the snakehead kingcroaker (Menticirrhus ophicephalus) exhibited moderate variation. We concluded that for the period 2017–2030, the adaptation costs (base year 2017) of accessible fishing credit and a bonus payment to artisanal fishers affected by El Niño events would be 3.9 million soles (US $ 1.2 million) in 2017 present value.

Distribution of maternal risk factors for orofacial cleft in infants in Indonesia: a multicenter prospective study.

The pathogenesis of orofacial cleft (OFC) is multifactorial, involving both genetic and non-genetic factors, the latter of which play a key role in the development of these anomalies. This paper addresses the incidence of OFC in Indonesia, with a focus on identifying and examining the distribution of contributory factors, including parental medical history, pregnancy history, and environmental influences. The study was conducted through the collection of primary data. An interdisciplinary research team from Indonesia administered a standardized questionnaire to parents who had children with OFC and who had provided informed consent. The case group comprised 133 children born with cleft lip and/or palate, and the control was 133 noncleft children born full-term. The risk factors associated with OFC anomalies were analyzed using the chi-square test and logistic regression. All statistical analyses were performed using SPSS version 25. A p-value of 0.05 or less was considered to indicate statistical significance. The study comprised 138 children, of whom 82 were boys (59.4%) and 56 were girls (40.6%). Among them, 45 patients (32.6%) presented with both cleft lip and cleft palate, 25 individuals (18.1%) had a cleft palate only, and 28 patients (20.3%) had a cleft lip only. OFC was found to be significantly associated with a maternal family history of congenital birth defects (p< 0.05), complications during the first trimester (p< 0.05), consumption of local fish (p< 0.05), caffeine intake (p< 0.05), prolonged medication use (p< 0.05), immunization history (p< 0.05), passive smoking (p< 0.05), and X-ray exposure during pregnancy (p< 0.05). The findings indicate close relationships between the incidence of OFC and maternal medical history, prenatal factors, and environmental influences.

Parasitism and branchitis in various fish species from 4 Cook County, Illinois inland freshwater lakes, 5-year survey, 2017-2021.

We investigated disease trends of concern for fish or public health in a 5-y (2017-2021) prospective survey of fish in Cook County, IL, inland lakes. Lesions were assessed in relation to fish species, lake type and location, season and collection year, and lake water chemistry parameters. Fish included bullheads (n = 98), common carp (n = 99), bluegill (n = 114), and largemouth bass (n = 118). Annually, fish collection and point-source water sampling were conducted in spring, summer, and fall from both seepage and impoundment lakes. Examinations included autopsy, wet-mount cytologic assessment for ectoparasites, and histopathology. No lesions of public health concern were detected. The most common abnormalities were branchitis (261 of 429; 60.8%) and endoparasitism (312 of 429; 72.7%). Branchitis was mild in most cases (189 of 261; 72.4%) and concurrent with branchial parasitism in 175 of 261 (67%) cases. Monogeneans were the most common gill parasites but did not influence branchitis severity (Kruskal-Wallis, p = 0.484). Using generalized ordered logistic regression, predictors of branchitis severity included fish species (p < 0.001), the interaction of lake or location and alkalinity (p < 0.001), and water temperature or season (p < 0.001). Endoparasites included tissue larval trematodes (metacercaria), nematodes, and cestodes (plerocercoids), enteric acanthocephalans, gastric trematodes, renal myxosporidia, biliary and gall bladder myxosporidia, enteric cestodes, and tissue microsporidia. Using generalized ordered logistic regression, variables influencing endoparasitism severity included species (p < 0.001), year (p < 0.001), chloride level (p = 0.009), and the interaction of year and chloride level (p < 0.001). Our results suggested overall good health of fish in sampled Cook County inland lakes and provide a foundation for continued monitoring of ecosystem and public health in the urban environment.

Development of low-cost natural adsorbent for the abatement of pollution from tannery effluent – A green technology

Tanneries are known to be one of the most polluting industries due to the generation of harmful contaminants at various stages, from the beam house to finishing. Each day, significant quantities of tannery wastewater containing contaminants like chromium salts are released into open areas, farmlands, rivers and other corpses of water. This practice poses a severe threat to the environment health, leading to extensive soil and water pollution. In this study, a biological material (scales of fish Catla catla) is employed as an adsorbent for biosorption of contaminants from tannery effluent. Every day a considerable amount of fish scales is generated and thrown away from the local fish market, which burdens the environment and causes environmental pollution. The primary emphasis of this study is to reduce wastewater pollution and the environmental burden of fish waste disposal. Two adsorbents were prepared by treating the dried fish scales with NaOH and Orthophosphoric acid to enhance the adsorbent properties by creating pores and roughness of the surface. Then, it was characterized using FTIR, SEM, and TGA analyses. After characterization, adsorbents were subjected to the adsorption of a standard chromium solution to detect the ideal adsorbent dose, contact time, and pH conditions of adsorption. The study's findings showed that during adsorption, the maximum uptake capacity of acid-treated adsorbent is found at pH 4 with an adsorbent dose of 20 g/L for a 60-minute contact time. That base-treated adsorbent is obtained at pH 2.50 with an adsorbent amount of 20 g/L for 4 hours of contact time. Then, the adsorbents were used to treat tannery effluents, and it was discovered that they successfully removed pollutants like chromic oxide, total suspended solids (TSD), total dissolved solids (TDS), BOD, COD, and others. The results indicated that the acid-treated adsorbent achieved optimal removal percentages for chromic oxide, BOD5, COD, TDS, and TSS at 72.82%, 42.85%, 56.12%, 13.37%, and 35%, respectively. Thus, the study concluded that acid and base-washed fish scale adsorbents are affordable and straightforward to use adsorbents for removing pollutants from tannery effluent.

Increasing trammel mesh size reduces biomass removal, mitigates discards and increases economic revenue in artisanal fisheries

Small-scale fishing plays a major role in regional economies worldwide and, with a large number of small vessels involved, it provides employment and livelihood to coastal communities. Generally recognized as more selective than other fishing practices, small-scale fishery can nevertheless be subjected to high rates of discards of both non-target species and small-sized individuals, which in turn could lead to both decreased incomes for fishers and increased depletion of fish stocks. However, if the relationship between fish size and price has long been assessed, the effect of enhanced size-selectivity of fishing gears and consequent economic gains has been little investigated. This study, set in the Porto Cesareo Marine Protected Area (Italy, Ionian Sea), aimed at testing effective strategies to improve trammel net selectivity, reducing discards and maximizing the income for fishers. Different mesh sizes (20, 22 and 24 mm) trammel nets were employed. The study consisted in 72 fishing days from July 2012 to September 2013 and each day involved experimental fishing with the three mesh sizes. A total of 16008 specimens (103 species) were collected but the analysis focused on the 18 most common species in the area for a total of 12782 individuals. Mesh size trammel nets of 20 mm and 22 mm yielded most of the biomass, 324.8 and 321.5 kg respectively, while the 24 mm mesh yielded 280.7 kg. The 24 mm mesh, even if accounted for lower income compared to the 22 mm mesh (2383.9 € vs 2590.5 €, respectively), provided significant 50% reduction of discards compared to the 20 and 22 mm mesh. The use of 24 mm mesh size was found to be an effective strategy to reduce the number of discarded organisms and, consequently, the pressure exerted on local fish stocks with associated higher revenue for fishers. The results of this study demonstrated that trammel net selectivity can improve and support conservation measures and concurrently increase profitability of local fishery.

Microbiological and chemical characteristics of porkfish inasua, traditional fish fermented from Maluku, Indonesia

Abstract. Mahulette F. 2023. Microbiological and chemical characteristics of porkfish inasua, traditional fish fermented from Maluku, Indonesia. Biodiversitas 25: 1-8. Porkfish inasua consisted of two types, i.e., with and without coconut sap. The research aimed to analyze the microbiological and chemical characteristics of two types of porkfish inasua. The microbiological characteristics are used to determine the role of microbes and product safety whereas the chemical characteristics, including proximate composition, amino acids, and fatty acids contents can determine the nutritional value for consumption. The sample of porkfish inasua was taken from traditional producers in Layeni, Teon, Nila, and Serua (TNS) Islands, Maluku, Indonesia. The microbiological analysis was done using the plate count method. From the measurement, the total number of halotolerant and coliform bacterial in porkfish inasua without sap were 6.2 log cfu/g and 6.1 log cfu/g, respectively. In comparison, the total of Bacillus and related genera in porkfish inasua with sap was 5.9 log cfu/g at the end of fermentation. The fat content of both types of inasua was around 17%. The total amino acids and fatty acids contents of porkfish inasua without sap at the end of fermentation were 15.31 and 57.08%, while porkfish inasua with sap were 15.85 and 63.81%, respectively. The dominant bacteria found in porkfish inasua without sap was Staphylococcus saprophyticus, while porkfish inasua with sap was Bacillus cereus. These two bacteria play a role in fermentation so porkfish inasua was safe for consumption. Generally, chemical characteristics of porkfish inasua with sap were better than those of porkfish inasua without sap, but statistically, it was not significantly different. This research can improve the quality of porkfish inasua as local fermented fish products in Maluku.

Oil spill in an amazon blackwater environment: Biochemical and physiological responses of local fish species

The accidental spill of petroleum asphalt cement (PAC) in São Raimundo (SR Harbor, located on the Rio Negro (Manaus, Amazonas, Brazil) was monitored through the analysis of polyciclic aromatic hydrocarbons (PAHs) in water and a set of biomarkers in fishes (exposure biomarkes: PAHs-type metabolites concentrations in bile; the activities of ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in liver. Effect biomarkers: lipid peroxidation concentration (LPO) in liver, acetylcholinesterase activity in brain, and genotoxic DNA damage in erythrocytes). Two fish species, Acarichthys heckelii and Satanoperca jurupari, were collected 10, 45, and 90 days after the PAC spill in São Raimundo. At the same time, fish were collected from the Tupé Sustainable Development Reserve (Tupé) which served as a reference area. The sampling periods were related to the rising waters of the natural flood pulse of the Rio Negro. Higher concentrations of PAHs in water were observed at 10 and 45 days and returned to the values of TP 90 days after the PAC spill, a period in which harbor waters rose about 0.2 m. Unlike the PAHs in water, biomarker responses in both fish species significantly increased following the PAC spill in SR. Hepatic ethoxyresorufin-O-deethylase (EROD), PAH-like metabolites in bile, and erythrocyte DNA damage increases, together with inhibition of acetylcholinesterase (AChE) activity in the brain were the most evident responses for both fish species. The calculated pyrolytic index showed mixed sources of PAHs (petrogenic and pyrolytic). The applied PCA-FA indicated important relationships between dissolved organic carbon (DOC) and PAHs concentrations in water, where DOC and PAHs concentrations contributed to biomarkers responses for both fish species in all collection periods.

Ecotourism: Another Benefit of Agro-Silvo-Fishery and Trigona Apiculture in Peatland Ecosystem of Baru Village, Banyuasin, South Sumatra

Agro-silvo-fishery and Trigona apiculture are two business models developed in the peatland ecosystem in Baru Village, Banyuasin District, South Sumatra. Since the beginning of 2022, two demo plots have been built in the same village landscape as part of the business model implementation. The system‘s agro-silvo-fishery was established by constructing a pond around a paddy field and planting betelnut, vegetables, and fruit trees. Local fish that had acclimated to the acidic peatland habitat were captured during the flooding and raised in the ponds. In the constrained biophysical and chemical conditions of swampy terrain, this method is thought to be the greatest way to provide a variety of revenue. Individual farmers cannot afford the costs associated with setting up this system, especially when it comes to constructing the pond and dykes. Individual farmers cannot afford the costs associated with establishing this system, especially when it comes to constructing the pond and dykes. Hence, support from the district and village government and program partners is valuable. The farmer group harvested corn and vegetables from the dykes and rice from the paddy fields in the first year, and fish were not ready for harvest. However, the local BUMDes saved the day by creating weekly regular fishing activities and competition events, generating revenue from tickets. Moreover, the Trigona apiculture became a popular place for those outside the village to learn free of charge. Based on profitability analysis, the NPV of establishing agro-silvo-fishery is Rp103.036.769 per 0.8 ha for 30 years, with additional income from ecotourism is estimated to reach Rp21.600.000 per year. The established demonstration plot has the potential to become an ecotourism destination, and the key is to maintain the surrounding flowers and plants as the source of food for bees and the water condition for the fish.

Fuzzy comprehensive evaluation of seawater quality of Larimichthys Crocea mariculture areas in Zhoushan, China

Context Aquaculture is an essential industry and assessing its impact on the environment, particularly water quality, is crucial for sustainable practices. This study aimed to comprehensively evaluate the seawater quality in the Dongji Island yellow croaker (Larimichthys crocea) aquaculture area by using the fuzzy comprehensive evaluation method and field survey. Aims The main objective of this study was to assess the seawater quality in the aquaculture area during 2 consecutive years (2019 and 2020) on the basis of monitoring data. Methods The researchers utilised the fuzzy comprehensive evaluation method to assess seawater quality in the Dongji Island yellow croaker aquaculture area. Seawater monitoring data from 6 months in 2019 and 6 months in 2020 were collected for the evaluation. The method included an annual average evaluation, and membership degrees were calculated for each year and individual months. Qualitative interviews with 30 local fish farmers were conducted to unravel the challenges faced by aquaculture water quality management. Key results The evaluation results indicated that the seawater quality in the aquaculture area was classified as Class I water in both 2019 and 2020 on the basis of the annual average evaluation. However, the membership degrees for 2019 were higher than those for 2020, suggesting that water quality was better in 2019. Furthermore, individual monthly evaluations in 2020 showed varying membership degrees, with May and June having higher membership degrees, indicating better water quality than in other months. August had the lowest membership degree, implying poorer water quality during that month. Conclusions The study demonstrated that the fuzzy comprehensive evaluation method is effective for evaluating seawater quality in aquaculture areas. It also concluded that the water quality in 2019 was superior to that in 2020, raising concerns about potential environmental degradation. Implications The quantitative and qualitative findings of this research have important implications for aquaculture practices in the Zhoushan area. The study highlights the need for continued monitoring and management of water quality to ensure sustainable aquaculture practices and adherence to water-quality policies. Future aquaculture endeavours in the region should consider the potential impact on water quality to maintain a healthy ecosystem.

Ecological generalism and physiology mediate fish biogeographic ranges under ocean warming.

Climate-driven species redistributions are facilitated by niche modifications that increase a species's chances of establishment in novel communities. It is well understood how range-extending species adjust individual niche traits when entering novel environments, yet whether modification of ecological niche traits collectively alters the pace of range extensions or contractions remains unknown. We quantified habitat niche, abundance, physiological performance and cellular defence/damage of range-extending coral reef fishes and coexisting local temperate fishes along a 2000 km latitudinal gradient. We also assessed their dietary and behavioural niches, and establishment potential, to understand whether ecological generalism facilitates successful range extension of coral reef fishes. The coral reef fish that increased all ecological niches, showed stronger establishment, increased physiological performance and cellular damage, but decreased cellular defence at their cold-range edge, whereas tropical species that showed unmodified ecological niches showed lower establishment. One temperate species showed decreased abundance, habitat niche width and body condition, but increased cellular defence, cellular damage and energy reserves at their warm-trailing range, while other temperate species showed contrasting responses. Therefore, ecological generalists might be more successful than ecological specialists during the initial stages of climate change, with increasing future warming strengthening this pattern by physiologically benefitting tropical generalists but disadvantaging temperate specialists.

Biodegradability and bioavailability of dissolved substances in aquaculture effluent: Performance of indigenous bacteria, cyanobacteria, and green microalgae

Aquaculture is a controlled aquatic farming sector and one of the most important human food sources. Fish farming is one of the predominant, fast-growing sectors that supply seafood products worldwide. Along with its benefits, aquaculture practices can discharge large quantities of nutrients into the environment through non-treated or poorly treated wastewater. This study aims to understand the nutrient composition of fish wastewater and the use of indigenous bacteria, cyanobacteria, and microalgae as an alternative biological treatment method. Wastewater samples from a local fish farming facility were collected and treated using six different species of cyanobacteria and microalgae include Chroococcus minutus, Porphyridium cruentum, Chlorella vulgaris, Microcystis aeruginosa, Chlamydomonas reinhardtii, and Fischerella muscicola. All the samples were incubated for 21 days, and the following parameters were measured weekly: Chemical oxygen demand (COD), phosphate, total dissolved nitrogen, and dissolved inorganic nitrogen. In addition, dissolved organic nitrogen (DON), bioavailable DON (ABDON), and biodegradable DON (BDON) were calculated from the mass-balance equations. Colorimetric and digestive methods were used for the parameter measurements. The results showed that C. reinhardtii reduced the soluble COD concentration by 74.6 %, DON by 94.3 %, and phosphorous by more than 99 %. Moreover, M. aeruginosa, and C. minutus significantly reduced inorganic nitrogen species (>99 %). This alternative fish wastewater treatment method was explored to gain insight into fish wastewater nutrient composition and to create a sustainable alternative to conventional fish wastewater treatment methods.