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This paper is a synthesis of the collection ‘Small fish for food and nutrition in the Global South: A value chain approach’. Small fish, often the most inexpensive available animal protein, are increasingly perceived as contributing to the food security and nutrition of poor and undernourished populations in the Global South. However, the value chains of these fish remain understudied. Therefore, we ask: what are the myriad ways through which small fish reach consumers in countries in Africa and Asia? The papers in this collection explore the value chains of marine and freshwater small fish, which are often consumed whole, and are rich in micronutrients. We give space to rich case studies of these value chains and further theoretical explorations of its various segments. They show a concern for the often-hidden power relations implicit in these value chains and food systems. Moreover, they show how, despite structural limits imposed by social categories or socio-economic transformation, the agency articulated by actors emerge as central, as they negotiate their engagement within small fish value chains. [ABSTRACT FROM AUTHOR]

For this study, a three-species food chain model that considers interactions between small fish, remora fish, and large fish has been developed. It is assumed that large fish consume small fish through the functional response of Holling type II. Remora fish are considered to benefit from eating the remaining parts of small fish hunted by larger fish. Remora fish may benefit from eating the parasites found in the bodies of large fish. The non-negativity and boundedness of the solution of the model are investigated. In addition, each potential stable state for the model has been determined. We also investigated the local stability of the model, which is close to the steady state. The Lyapunov function and geometric technique are used to investigate the global stability of the model. It has been found that the increase in the refuge rate for small fish contributes to the instability of the model. It has been observed that the model may show unstable behaviour due to an increase in the rate of consumption of small fish by big fish. It has been found that the density of remora fish may rise because of their mutualistic relationship with large fishes. [ABSTRACT FROM AUTHOR]

Fish can be a key strategy in addressing the global food and nutrition insecurity challenges. Fish nutrient data are critical for policy development targeting to reduce these problems. Despite this, much of the published studies on nutritional characteristics of fish have focused on marine ecology and there is little information on natural freshwater fish habitats like inland delta areas. This study investigated the nutrient composition of Okavango Delta fishes and their potential contribution to the recommended nutrient intake. Fish species sampled were Clarias ngamensis, Oreochromis andersonii, Schilbe intermedius, Marcusenius altisambesi, Brycinus lateralis, Barbus poechii and Tilapia sparrmanii. The nutrients analyzed were moisture, ash, proteins, Na, K, Ca, Mg, P and Zn. The small fishes (B. lateralis and B. poechii) had higher mineral content; Ca (643–968 mg/100 g), Mg (47–49 mg/100 g) and Zn (2.8–3.6 mg/100 g) compared to the larger species with average mineral content; Ca (73–460 mg/100 g), Mg (23–35 mg/100 g), Zn (1.2–2.9 mg/100 g). The most nutrient-dense species recognized were B. poechii and B. lateralis followed by the large species, M. altisambesi. These species illustrated the potential to contribute 80–121% Ca, 32–47% Mg and 70–150% Zn of the recommended nutrient intake to children (1–9 years), pregnant women and the elderly (65 + years). The study recommends prioritizing small and some large species (M. altisambesi and T. sparrmanii) for polyculture systems, primarily for securing food and nutrition security for local communities. [ABSTRACT FROM AUTHOR]

Objective: Although small fish are an important source of micronutrients, the relationship between their intake and mortality remains unclear. This study aimed to clarify the association between intake of small fish and all-cause and cause-specific mortality. Design: We used the data from a cohort study in Japan. The frequency of the intake of small fish was assessed using a validated FFQ. The hazard ratio (HR) and 95 % confidence interval (CI) for all-cause and cause-specific mortality according to the frequency of the intake of small fish by sex were estimated using a Cox proportional hazard model with adjustments for covariates. Setting: The Japan Multi-Institutional Collaborative Cohort Study. Participants: A total of 80 802 participants (34 555 males and 46 247 females), aged 35–69 years. Results: During a mean follow-up of 9·0 years, we identified 2482 deaths including 1495 cancer-related deaths. The intake of small fish was statistically significantly and inversely associated with the risk of all-cause and cancer mortality in females. The multivariable-adjusted HR (95 % CI) in females for all-cause mortality according to the intake were 0·68 (0·55, 0·85) for intakes 1–3 times/month, 0·72 (0·57, 0·90) for 1–2 times/week and 0·69 (0·54, 0·88) for ≥ 3 times/week, compared with the rare intake. The corresponding HR (95 % CI) in females for cancer mortality were 0·72 (0·54, 0·96), 0·71 (0·53, 0·96) and 0·64 (0·46, 0·89), respectively. No statistically significant association was observed in males. Conclusions: Intake of small fish may reduce the risk of all-cause and cancer mortality in Japanese females. [ABSTRACT FROM AUTHOR]

Abstract Objective: Although small fish are an important source of micronutrients, the relationship between their intake and mortality remains unclear. This study aimed to clarify the association between intake of small fish and all-cause and cause-specific mortality. Design: We used the data from a cohort study in Japan. The frequency of the intake of small fish was assessed using a validated FFQ. The hazard ratio (HR) and 95 % confidence interval (CI) for all-cause and cause-specific mortality according to the frequency of the intake of small fish by sex were estimated using a Cox proportional hazard model with adjustments for covariates. Setting: The Japan Multi-Institutional Collaborative Cohort Study. Participants: A total of 80 802 participants (34 555 males and 46 247 females), aged 35–69 years. Results: During a mean follow-up of 9·0 years, we identified 2482 deaths including 1495 cancer-related deaths. The intake of small fish was statistically significantly and inversely associated with the risk of all-cause and cancer mortality in females. The multivariable-adjusted HR (95 % CI) in females for all-cause mortality according to the intake were 0·68 (0·55, 0·85) for intakes 1–3 times/month, 0·72 (0·57, 0·90) for 1–2 times/week and 0·69 (0·54, 0·88) for ≥ 3 times/week, compared with the rare intake. The corresponding HR (95 % CI) in females for cancer mortality were 0·72 (0·54, 0·96), 0·71 (0·53, 0·96) and 0·64 (0·46, 0·89), respectively. No statistically significant association was observed in males. Conclusions: Intake of small fish may reduce the risk of all-cause and cancer mortality in Japanese females.

Fish is readily available to fishing communities. Given the high nutritional value of fish, these communities are expected to have better nutritional status, compared to non-fishing communities. However, this assumption is not well studied across coastal fishing communities in Ghana. Hence, this cross-sectional study was conducted to investigate the nutritional status, dietary patterns, and fish consumption of children living in coastal fishing communities in Ghana. Nutritional status of 384 randomly selected children was assessed using the mid-upper arm circumference (MUAC) measurement. MUAC less than 12.5 cm was used as the cutoff to identify malnourished children. Food and fish consumption patterns were assessed using an adopted and pretested food frequency questionnaire. The findings showed a prevalence of 0.5% wasting among surveyed children. The mean dietary diversity score (DDS) of the study participants was 4.3 ± 1.2. The mean DDS of the children of fisher mothers was less than that of the children of the female caregivers who are involved in other occupations. However, no significant difference was observed in the DDS across the coastal regions. Seventy eight percent of the children who participated in the study consumed an adequately diversified diet, and more than 40 different small fish species were consumed across the four coastal regions. The average median weekly fish intake among the children in the study sample was 213 (64–468) g. Considering that one-third of the employed respondents were fisherfolk, coupled with the availability of a great diversity of small fish in the communities, the findings of our study suggest that there is great potential to incorporate small fish into strategic interventions aimed at improving nutrition, food security, and achieving economic sustainability in these communities. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa has a high prevalence of food insecurity. Small pelagic fish such as Silver cyprinid (Rastrineobola argentea) which is indigenous to Lake Victoria, can be a nutritious animal sourced food that contributes to a more nutrient dense diet. Potential sustainable catch of Silver cyprinid is estimated at 2 million tonnes yearly, which is four times the amount of the current catch. Whole sun-dried Silver cyprinid was purchased from several markets in Kenya and analysed for nutrient composition, microbial counts and metal content. The results show that utilizing the whole potential catch of Silver cyprinid would provide a significant daily source of vitamin B12, calcium, zinc and iron to the roughly 33 million people living in the Lake Victoria basin. Heavy metal concentration appears to be low, but other food safety aspects like microbial counts call for value chain improvements. We conclude that the underutilized potential of sun-dried Silver cyprinid could substantially contribute to fight malnutrition and food insecurity by providing an affordable nutrient dense animal sourced food to a large number of people. It also highlights the need to improve the value chains to increase the safety of these products. [ABSTRACT FROM AUTHOR]

Small fish are an important part of the diet in Ghana, but malnutrition rates remain high. The nutritional quality of fish consumed in Ghana may be affected by food processing and cooking practices, but the extent to which these processes are practiced among poor Ghanaian households along the coastal belt is unknown. This study explored how poor Ghanaian households process, prepare, and cook meals containing small fish. This exploratory qualitative study used Attride-Stirling thematic network analysis. Respondents were purposively sampled from fishing communities in the coastal regions of Ghana. One-on-one interviews were performed by trained field assistants, audio recorded and videotaped, and transcribed for further data analysis. The most common small fish species identified were anchovies and herrings. Anchovies were fried and eaten whole. Herrings were eaten either smoked or fresh; for fresh herring, the head, fins, and viscera were removed before boiling. Herrings were smoked with the head and viscera; however, both the head and viscera were removed before being added to boiling soup and were not consumed. Anchovies were fried for 10 min, and herrings were boiled for 15–30 min. Processing methods and further meal preparation depend on the small fish species. Nutrient composition and contribution of small fish depend on the processing method, preparation method, and what tissues are eaten. Thus, these results will be of importance for sampling schemes for food composition tables and for the calculation of nutrient intake from small fish. [ABSTRACT FROM AUTHOR]

Marine fish are good source of essential macro- and micronutrients and major food items in coastal areas in Bangladesh. However, there is no review that details the nutritional value of marine fish in Bangladesh. Therefore, this review focuses on the nutrient composition of marine fish in Bangladesh and how the marine fish can address common nutrient deficiencies among women and children. Nutrient composition data was collected through literature searching in databases and source, including PubMed, Web of Science, Google Scholar, ScienceDirect, WorldFish, and Bangladesh-based database Banglajol. Calculation was carried out to present how one serving marine fish could potentially meet the daily requirement of protein, iron, zinc, calcium, vitamin A, and docosahexaenoic acid (DHA) for pregnant and lactating women and children aged 6–23 months. A total of 97 entries covering nutrient composition analysis of 67 individual fish species were extracted from 12 articles published between 1993 and 2020. Included articles contained analysis of proximate composition, vitamins, minerals, fatty acids, and amino acid. Twelve minerals and nine vitamins were analyzed and reported. The average energy, protein, fat, and ash content per 100 g edible raw marine fish was 343.58 kJ, 16.76 g, 4.16 g, and 2.22 g, respectively. According to available data, marine fish are good sources of protein, zinc, calcium, and DHA. Pelagic small fish, which are mainly captured by artisanal small-scale fishers, had more nutritional value than other categories of fish. Furthermore, marine small fish were found more nutritious than commonly consumed freshwater fish types in Bangladesh, including major carps, introduced carps, and tilapia. Therefore, the study concludes that marine fish have high potential to address malnutrition in Bangladesh. There was scarcity of literature regarding the nutrient composition of marine fish in Bangladesh and in South Asia as a whole, so more comprehensive quality research in this area is recommended.

Copyright of Biology Teaching is the property of East China Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prahoc is a traditional, fermented fish product in Cambodian diets. Fermented products like Prahoc may play a range of beneficial roles nutritionally, culturally, and financially. However, the use of freshwater fish and long-term storage may also pose food safety risks of parasites and microorganisms. We conducted a mixed-methods study of Prahoc to describe the complex risks and benefits of this food that included semi-structured interviews (prahoc-producing households, n=22; small and medium enterprises n=6), production observation, sample collection and analysis of nutrient composition and food safety parameters. Nutrient composition analysis showed that while Prahoc contributes small amounts of zinc, iron, and other key minerals to the diet, it is also very high in sodium (∼101,621 mg kg-1). Food safety analyses showed that while further tests are needed to resolve Listeria monocytogenes, Salmonella spp., and Vibrio risks, all samples were in compliance with the Cambodia Standards for Prahoc, and there was no evidence of parasites. Participants described Prahoc as playing an essential dietary and cultural role, and also making important contributions to household welfare, particularly within households and businesses that sold Prahoc. Despite the potential risks of microbial food safety and high sodium intake, Prahoc production offers benefits by adding value to fresh fish, reducing loss and waste, and preserving the harvest. However, Prahoc production depends on fish availability and is limited by declining access and high prices. Thus, freshwater fisheries management should take into account Prahoc production activities, an important value chain activity that contributes to the livelihoods of rural Cambodian communities. [ABSTRACT FROM AUTHOR]

In freshwater ecosystems, flood pulses, the degree of connectivity between environments, and the vegetation mosaic are among the main variables affecting environmental structure at the landscape scale. At a finer scale, local limnological conditions seem to be more important for structuring river fish assemblages. However, rather than exerting isolated effects, these limnological characteristics can have combined impacts on the environment. We evaluated the main drivers of the spatial structuring of fish trophic guilds in the littoral zone of lakes in the Upper Paraná River floodplain (UPRF) and determined the relative importance of limnological conditions, spatial distance, and riparian vegetation. We sampled fish and limnological variables in June, September, and December of 2011, and classified the fish species into trophic guilds. We used variation partitioning analysis to assess the influence of the three sets of predictors and distance-based redundancy analysis to visualize the position of samples, as described by the composition of trophic guilds in multivariate space. The distribution of trophic guilds was mainly influenced by limnological variables, i.e., conductivity, chlorophyll a, and pH, in periods of low water. Spatial and riparian vegetation predictors, despite being low, also influenced the distribution because limnological variables and riparian vegetation of the UPRF have a well-defined spatial structure due to differences between rivers. The lakes with Class III riparian vegetation (dominated by tree species) supported most of the trophic guilds, including insectivores. This indicates that allochthonous materials, even when they occur in smaller proportions, contribute to the structuring of fish communities in periods of low water. [ABSTRACT FROM AUTHOR]

Fish is an important source of easily digestible animal protein and other essential nutrients. It plays a pivotal role in food security and poverty alleviation in developing countries. However, the nations of the global South consume a limited number of fish species. This study aimed to evaluate the macronutrient and mineral composition of Whole fish (Labeobarbus intermedius, Garra quadrimaculata) and fillet (Oreochromis niloticus, Labeobarbus intermedius). A total of 64 fish samples were collected from Gilgel Gibe reservoir, Ethiopia, and analysed for its macronutrient and mineral composition. The proximate composition and mineral contents of fillets and whole body samples were determined. The whole fish showed a much higher fat and ash percentage than the fillets (p < 0.05). The fillets contained a much higher protein concentration than the whole fish (p < 0.05). The higher Ca:P ratios in whole fish compared to fillet in our study confirm the importance for a healthy human skeletal development, especially in diets where Ca is typically lacking. Whole Garra appeared to be containing important trace elements such as zinc and iron, a feature that was not found to the same extent in the whole Labeobarbus. These differences may find its origin in the feeding pattern of these fish species in the reservoir. The advantage of benthic species such as Garra to enrich the human diet with essential minerals may, however, coincide with the accumulation of toxic heavy metals as a potential result of soil erosion. [ABSTRACT FROM AUTHOR]

There is a need for expanding the utilization of small fish as they constitute an undervalued and important source of protein and micronutrients in many developing countries suffering from micronutrient deficiencies. One way to increase consumption and health benefits is to add nutrient‐rich fish meal into staple food ingredients. In this study, Response Surface Methodology (RSM) was applied to optimize the processing of an instant rice‐based cereal enriched with anchovy powder. The Box‐Behnken design was used to study the effect of principal processing variables (drying temperature, drum rotation speed, and slurry solids concentration) on product water activity, color, bulk density, and water solubility index. Viscosity, consistency, and cohesiveness of the reconstitute cereal were also evaluated. Empirical models were developed to describe the relationship between independent and dependent variables and showed regression coefficients (R2) ranging between 71% and 98%. Higher drying temperatures resulted in reduced water activity, darker product color, and lower consistency. While drum speed influenced (p <.05) product color and water‐binding capacity, bulk density, and consistency of the reconstituted product was associated with slurry solids concentration. Optimal processing conditions obtained from the study were temperature of 130°C, drum speed of 9.3 rpm, and solids concentration of 20.5%. These conditions would be useful in the production of brown rice‐based instant cereal enriched with anchovy powder with desired quality properties. [ABSTRACT FROM AUTHOR]

Fish farmers aim to maximise fish weight relative to the feed inputs needed to turn a profit. Yet, many farmers in Africa lack the cash flow to grow large fish and many consumers prefer, or are limited to purchasing, small fish. This study aimed to intentionally produce small tilapia in cages by assessing the effects of higher stocking densities and shorter growth cycles on production and financial efficiency. An experiment with 3 treatments and 6 replicates took place on Lake Victoria. The first treatment (T1) used a stocking density of 2.9 ± 0.3 kg per m−3 and aimed to produce fish to an average body weight (ABW) of 400 g (final ABW = 500.33 ± 31.01 g after 138 days). Treatment two (T2) did the same but with double the stocking density (5.9 ± 0.3 kg per m−3), resulting in a final ABW of 439.22 ± 22.22 g over 138 days. The third treatment (T3) partially harvested 50% of the cage (after 76 days) once reaching an ABW of 230.92 ± 22.55 g. The remaining fish in T3 were on-grown for a total of 138 days (final ABW = 499.86 ± 15.95 g). A fourth production scenario (M1) based on data from T3, modelled a 100% harvest after 76 days of culture. There were no significant differences in mortality between treatments. There were no statistical differences in the feed conversion ratio (FCR) between T1 (1.51 ± 0.03) and T2 (1.49 ± 0.02), though T3 was statistically lower (1.46 ± 0.02; p = 0.03). Cages in T1 had a higher proportion of fish between 400 and 599 g while fish in T2 were mostly between 300 and 499 g. T3 had a bimodal distribution with most fish either in 200–299 g or 400–499 g. There was little effect on average price per kg for T1 (3.0 ± 0.01 USD) and T2 (2.98 ± 0.01 USD), though T3 (2.89 ± 0.04 USD) was significantly lower (p = 0.001). Overall, T2 had significantly higher gross margins (17% ± 2.08) than T1 (13% ± 2.3, p = 0.021) and T3 (7.2% ± 2.43, p = 0.001), while M1 had the lowest gross margins (−11.8% ± 5.5). The results suggest that farmers can increase stocking densities. Some farmers can use partial harvesting strategies or shorter cycles to produce small tilapia and achieve faster cash flows, though the economic margins are lower. Such approaches can provide opportunities for poorer farmers and consumers. • Increasing stocking density had the best financial and technical results. • Partial harvesting for mixed size variation had no effect on survival or growth. • Shortening production cycle and growing small fish had lowest gross margins. • However, shortening cycles and partial harvests can allow to increase cash flow. • Lower-income consumers can thus benefit from accessing small tilapia. [ABSTRACT FROM AUTHOR]

In recent years, small fishes such as zebrafish and medaka have been widely recognized as model animals. They have high homology in genetics and tissue structure with humans and unique features that mammalian model animals do not have, such as transparency of embryos and larvae, a small body size and ease of experiments, including genetic manipulation. Zebrafish and medaka have been used extensively in the field of neurology, especially to unveil the mechanisms of neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, and recently, these fishes have also been utilized to understand neurodevelopmental disorders such as autism spectrum disorder. The turquoise killifish has emerged as a new and unique model animal, especially for ageing research due to its unique life cycle, and this fish also seems to be useful for age-related neurological diseases. These small fishes are excellent animal models for the analysis of human neurological disorders and are expected to play increasing roles in this field. Here, we introduce various applications of these model fishes to improve our understanding of human neurological disorders.

The present paper discusses acceleration in the swimming of a small three-dimensional fish with two motions, carangiform and anguilliform. Flow fields generated by fish deformations are investigated numerically by the constrained interpolation profile method in combination with an immersed boundary method. The three-dimensional vortical structure visualized using a second invariant and the pressure field around the fish body show that a fish with anguilliform motion accelerates more rapidly than one with carangiform motion because of a larger thrust due to the strong transverse vortex in the wake of the fish and a large pressure variation around the fish body. It is also found that the time variations of inline swimming speed of a small fish and the fluid force acting on it can be estimated using a free-fall model, and the fluid force can be expressed by a linear function of the fish speed. This function consists of a thrust part that is independent of fish speed and a viscous drag part that is proportional to fish speed. Thus, time histories of swimming speed, swimming distance, and fluid force can be predicted by simple functions from rest to terminal speed.

In Bangladesh, homestead pond aquaculture currently comprises a polyculture of large fish species but provides an ideal environment to integrate a range of small fish species. Small fish consumed whole, with bones, head and eyes, are rich in micronutrients and are an integral part of diets, particularly for the poor. Results from three large projects demonstrate that the small fish, mola ( Amblypharyngodon mola) contributes significantly to the micronutrients produced from all fish, in homestead ponds, in one production cycle. Mola contributed 98%, 56% and 35% of the total vitamin A, iron and zinc produced, respectively, despite comprising only 15% of the total fish production by weight. If consumed within the household, mola could contribute half of the vitamin A and a quarter of the iron intake recommended for a family of four, annually. Homestead ponds are uniquely accessible to women who prepare the household food. Further dissemination of the carp-small fish technology provides opportunities to target women and men together for training on fish production and consumption, nutrition and gender equity. Women only training is also recommended to enable them to engage fully, without feeling dominated by men. Partnering with the fisheries and health sectors will encourage sustainable uptake of this promising technology. Clearly, dissemination could have significant health benefits; however, improved monitoring and evaluation, particularly of dietary diversity and diet quality are essential. Research priorities should also include the production techniques of other small indigenous fish species (SIS), besides mola, and the power dynamics between women and men in operating homestead ponds. [ABSTRACT FROM AUTHOR]

Marine fish are good source of essential macro- and micronutrients and major food items in coastal areas in Bangladesh. However, there is no review that details the nutritional value of marine fish in Bangladesh. Therefore, this review focuses on the nutrient composition of marine fish in Bangladesh and how the marine fish can address common nutrient deficiencies among women and children. Nutrient composition data was collected through literature searching in databases and source, including PubMed, Web of Science, Google Scholar, ScienceDirect, WorldFish, and Bangladesh-based database Banglajol. Calculation was carried out to present how one serving marine fish could potentially meet the daily requirement of protein, iron, zinc, calcium, vitamin A, and docosahexaenoic acid (DHA) for pregnant and lactating women and children aged 6-23 months. A total of 97 entries covering nutrient composition analysis of 67 individual fish species were extracted from 12 articles published between 1993 and 2020. Included articles contained analysis of proximate composition, vitamins, minerals, fatty acids, and amino acid. Twelve minerals and nine vitamins were analyzed and reported. The average energy, protein, fat, and ash content per 100 g edible raw marine fish was 343.58 kJ, 16.76 g, 4.16 g, and 2.22 g, respectively. According to available data, marine fish are good sources of protein, zinc, calcium, and DHA. Pelagic small fish, which are mainly captured by artisanal small-scale fishers, had more nutritional value than other categories of fish. Furthermore, marine small fish were found more nutritious than commonly consumed freshwater fish types in Bangladesh, including major carps, introduced carps, and tilapia. Therefore, the study concludes that marine fish have high potential to address malnutrition in Bangladesh. There was scarcity of literature regarding the nutrient composition of marine fish in Bangladesh and in South Asia as a whole, so more comprehensive quality research in this area is recommended., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Contaminant-induced feeding inhibition has direct and immediate consequences at higher levels of biological organization, by depressing the population consumption and thus hampering ecosystem functioning (e.g. grazing, organic matter decomposition). Thus, similarly to lethality and avoidance, feeding is mechanistically linked to ecosystem processes and is therefore an unequivocal ecologically meaningful response. The objective of the present study was to develop a short-term assay with the small freshwater fish Danio rerio , based on feeding. For this, a methodology to easily and precisely quantify feeding was first optimized: each fish was allowed to prey on ten live Daphnia magna juveniles, for 1 h, just before the end of a 48-h exposure test period. Secondly, copper sensitivity of feeding relatively to survival and growth was evaluated. At the growth EC20 (40 μg L −1 ), feeding was inhibited by 53%, and at the feeding EC50 (36 μg L −1 ), mortality was negligible (1.3%). Integrating feeding and survival revealed a 97% depression in the population consumption at the LC50 (61 μg L −1 ). Thirdly, the influence of pH, conductivity and hardness on the feeding background variability was assessed by assaying waters collected at eight reference sites and was found to be negligible, within tested ranges. Fourthly, feeding assays with natural waters contaminated with acid mine drainage confirmed the integration of lethality and feeding to be pertinent at estimating contaminant effects at higher levels of biological organization. [ABSTRACT FROM AUTHOR]

In recent years, small fishes such as zebrafish and medaka have been widely recognized as model animals. They have high homology in genetics and tissue structure with humans and unique features that mammalian model animals do not have, such as transparency of embryos and larvae, a small body size and ease of experiments, including genetic manipulation. Zebrafish and medaka have been used extensively in the field of neurology, especially to unveil the mechanisms of neurodegenerative diseases such as Parkinson's and Alzheimer's disease, and recently, these fishes have also been utilized to understand neurodevelopmental disorders such as autism spectrum disorder. The turquoise killifish has emerged as a new and unique model animal, especially for ageing research due to its unique life cycle, and this fish also seems to be useful for age-related neurological diseases. These small fishes are excellent animal models for the analysis of human neurological disorders and are expected to play increasing roles in this field. Here, we introduce various applications of these model fishes to improve our understanding of human neurological disorders. [ABSTRACT FROM AUTHOR]

Copyright of Biota Neotropica is the property of Biota Neotropica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By using a set of pelagic gillnets with eight mesh sizes, an investigation was made on the spatial distribution of small fishes in submerged macrophyte habitats in a shallow macrophytic lake (Niushan Lake) in the middle reach of Yangtze River in summer, 2005. The fish composition, abundance, and size structure were examined along a biomass gradient of the most dominant submerged macrophyte Potamogeton maackianus. A total of 1124 individuals from 13 fish species were caught during the study period. According to the abundance and occurrence, sharpbelly Hemiculter leucisculus and redfin culter Cultrichthys erythropterus were identified as the two dominant small pelagic fishes in the lake. There existed dome-like relationships between the fish species richness and Shannon diversity index and the submerged macrophyte biomass within its observed range. For the two dominant small fishes, their abundance was significantly positively correlated with macrophyte biomass, and the average sizes of the individuals of H. leucisculus and C. erythropterus were larger in un-vegetated habitat but smaller in heavily vegetated habitats, indicating that the young individuals tended to live in dense submerged macrophyte covers. Other two habitat factors, i. e. , water depth and distance to shore, had little effects on the spatial distribution of the two fish species. It was inferred that P. maackianus cover should be the important refuge habitat for the two dominant small-sized fishes in Niushan Lake, and it would be necessary to protect or restore the submerged macrophyte covers including P. maackianus. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)