Target Fish Species Research Articles

Stock estimation, species composition and biodiversity of target reef fishes in the lesser Sunda-Banda Seascape (East Flores, Alor and South West Maluku regencies), Indonesia

This study aimed to fill the gap of knowledge on this group of fishes by estimating the natural stock, species composition and biodiversity of target reef fishes from three regencies; Alor, East Flores (Flores Timur) and Southwest Maluku (Maluku Barat Daya/MBD) using underwater visual census method. A total of 176 species belong to 19 families of economically important target fish were recorded from 62 survey sites. The highest estimated stock is located in Southwest Maluku Regency – based on both abundance and biomass values, followed by Alor Regency and the lowest in East Flores Regency. Target fish species from the family of Caesionidae has the highest composition both based on abundance (74%) and biomass (40%). The highest species composition of target fish is from Pterocaesio tile (57.65%) which is more than 50% of the overall target fish. Community structure of target fish in the three regencies is still in a relatively good condition based on diversity index (H’), evenness (E) and no domination (C) of a single species occurs inside the target fish community, with exception in Alor Regency where the community of target fish is indicated to be under pressure. Biodiversity index by Bray-Curtis analysis in each location shows that most of the sites have the similarity of 67.51%, suggesting that there is not much difference in terms of target fish community structure between the three regencies.

Developing Cost-Effective Design Guidelines for Fish-Friendly Box Culverts, with a Focus on Small Fish.

Low-level river crossings can have negative impacts on freshwater ecosystems, including blocking upstream fish passage. In order to restore upstream fish passage in culverts, we developed physically-based design methods to yield cost-effective culvert structures in order to maintain or restore waterway connectivity for a range of small-bodied fish species. New guidelines are proposed for fish-friendly multi-cell box culvert designs based upon two basic concepts: (1) the culvert design is optimised for fish passage for small to medium water discharges, and for flood capacity for larger discharges, and (2) low-velocity zones in the culvert barrel are defined in terms of a percentage of the wetted flow area where the local longitudinal velocity component is less than a characteristic fish speed linked to swimming performances of targeted fish species. This approach is novel and relies upon an accurate physically-based knowledge of the entire velocity field in the barrel, specifically the longitudinal velocity map, because fish tend to target low-velocity zone (LVZ) boundaries. The influence of the relative discharge threshold Q1/Qdes, characteristic fish swimming speed Ufish, and percentage of flow area on the size of box culvert structures was assessed. The results showed that the increase in culvert size and cost might become significant for a smooth culvert barrel with Ufish < 0.3 m/s and Q1/Qdes > 0.3, when providing 15% flow area with 0 < Vx < Ufish. Similar trends were seen for culvert barrel with recessed cell(s).

Fish consumption on the Amazon: a review of biodiversity, hydropower and food security issues.

The lack of knowledge about the majority of fish species harvested in Amazonian small-scale fisheries, in association with impacts from hydroelectric power plants, may lead to biodiversity loss and a decrease in the protein food supply for riverine Amazonians. This study uses existing datasets on fisheries and riverine developmental projects to infer effects associated with fish losses where actual data and outcomes are not available. The targeted fish species' status may be regarded as either threatened or there being no knowledge of their conservation requirements, biology or ecology. Among the 90 Amazonian fish species that are the most important for the diet of the riverine fishers, 78% are not assessed or their biological information is unknown, according to the IUCN Red List. Consequently, the effects created by the thoroughly disregarded trade-off between energy generation and food security in the planning of Amazonian land use have been worsened by the lack of biological and ecological information on fish species.

Fishers’ Local Ecological Knowledge (LEK) on Connectivity and Seascape Management

In developing countries where data and resources are lacking, the practical relevance of Local Ecological Knowledge (LEK) to expand our understanding of the environment has been highlighted. The potential roles of the LEK varies from direct applications such as gathering environmental information to a more participative involvement of the community in the management of resources they depend on. Fishers’ LEK could therefore be useful in order to obtain information to advance management of coastal fisheries. Many targeted fish species migrate between habitats to feed, spawn or recruit, connecting important habitats within the seascape. LEK could help provide answers to questions related to this connectivity and the identification of fish habitat use and migrations for species and areas where such knowledge is scarce. Here we assess fishers’ LEK on connectivity between multiple habitats within a tropical seascape, investigate the differences in LEK among fisher groups and the coherence between LEK and conventional scientific knowledge (CSK). The study was conducted in Zanzibar, Tanzania, a tropical developing country, in 2017. One hundred and thirty-five semi-structured interviews were conducted in six different locations focusing on fish migrations, and matching photos of fish and habitats. Differences between fisher groups were found, where fishers travelling further, exposed to multiple habitats, and fish with multiple gears had a greater knowledge on connectivity patterns within the seascape than those that fish locally, in single habitats and with just one type of gear. A high degree of overlap in LEK and CSK was found, highlighting the potential benefits of collaboration between scientists and fishers and the use of LEK as complementary information in the management of small-scale fisheries.

Age and Growth of Spotted Snakehead, Channa punctata from the Ganga River

The present study was undertaken to estimate age and growth of the spotted snakehead Channa punctata (Bloch, 1793) from the Ganga River, based on 390 fish samples collected during August 2016 to July 2017. Each of the 3 otoliths (lapillus, asteriscus and sagitta) were dissected out, cleaned and observed to identify the annual rings. Based on clarity of annuli and ease of reading, sagittae (whole as well as sectioned) were selected for age estimation. Standard procedures were followed to prepare and study the age structures viz., the otoliths and scales. The alternating opaque and translucent bands present on the ageing structures were interpreted as annuli. Amongst the 3 methods used for age estimation, the sectioned otolith exhibited highest percentage of agreement (92.4) between readers, and least values of average percent of error (2.68) and coefficient of variation (2.36). Age estimates from sectioned otoliths were taken to develop the von Bertalanffy growth equation [Lt = 31.5(1 – e–0.29(t+ 1.06))] for the target fish species. The observed and calculated lengths in the fish did not vary significantly. Thus, the sectioned otoliths may be used for precise age estimation as well as calculation of various age-based population parameters of C. punctata inhabiting the river Ganga.

Neither Diplectanum nor specific: a dramatic twist to the taxonomic framework of Diplectanum (Monogenea: Diplectanidae)

The taxonomy of the genus Diplectanum has been exclusively based on morphological features, with 28 nominal species parasitic on perciform fishes recognised. We used molecular data, to our knowledge for the first time, to evaluate the taxonomic framework of Diplectanum, infer the relationships amongst species attributed to this genus, re-assess the degree of host specificity and explore the population genetic structure of Diplectanum spp. parasitising Mediterranean sciaenids, which are potential target fish species for aquaculture diversification in the region. A minimum of 10 specimens of Diplectanum spp. were sequenced per host species (Argyrosomus regius, Sciaena umbra, Umbrina canariensis and Umbrina cirrosa) and locality (Burriana, Sant Carles de la Ràpita and Santa Pola (Spain)) together with five individuals of the type species Diplectanum aequans. Sequences of partial 28S rDNA and internal transcribed spacer region of Diplectanum spp. were analysed together with those from other Diplectanidae spp. in GenBank using Bayesian inference and maximum likelihood phylogenetic methods. Population genetic analyses were performed using cytochrome c oxidase subunit I gene sequences for a diplectanid species with a wide distribution across host species and localities. Results showed that Diplectanum was not monophyletic, nor were the specimens infecting sciaenids. Instead they formed two separate clades, 26.1–28.6% divergent for the internal transcribed spacer and 13.2–16.9% for the 28S region from D. aequans. Altogether, our results suggest that these specimens represent two distinct new genera from Diplectanum and five putative species with low host specificity. It is likely that morphological variability has led to the description of more species than were detected by molecular methods. In contrast to other monogeneans, Diplectaninae gen. spp. are chiefly generalists. Nonetheless, intraspecific genetic divergence in the internal transcribed spacer region of Diplectaninae gen. spp., and population genetic analyses of one presumed generalist species, Diplectaninae gen. sp. 1.2, showed significant variation between subpopulations living on different hosts. The intraspecific genetic structure by host also suggests different cross-infection potential amongst sciaenid species.

A data-limited approach for estimating fishing mortality rates and exploitation status of diverse target and non-target fish species impacted by mixed multispecies fisheries

Abstract Most towed-gear bottom-trawl fisheries catch several target and myriad non-target species with the same gears at the same time. Differences in species’ exposure and sensitivity to fishing mortality lead to diverse outcomes in terms of population status. We develop and apply a data-limited approach for estimating fishing mortality rates and exploitation status of all species impacted by a mixed fishery. The approach requires (i) estimates of fishing mortality F by species based on area swept by towed gears, gear efficiency, and modelled species’ distributions and (ii) estimation of spawning potential ratio (SPR), by species, from cross-species relationships between maximum body size and other life history parameters. Application in the North Sea reveals per cent SPR (%SPR) (reproductive output per recruit at estimated F/reproductive output at F=0) by species ranges from 2.4 to 99.3. For 10% of species, including 57% of elasmobranchs, %SPR &amp;lt; 20 (a limit reference point), while for 17% of species 20 &amp;lt; %SPR &amp;lt; 40, and for 72% %SPR &amp;gt; 40 (implying relatively high and sustainable yield and low risk of population collapse). Applications of the approach include community-wide stock status assessment, state of environment reporting, risk assessment, and evaluating effects of changes in fishing distribution and intensity.

The importance of spatiotemporal fish population dynamics in barrier mitigation planning

In this study, we propose a novel framework combining spatially explicit population viability analysis and optimization for prioritizing fish passage barrier mitigation decisions. Our model aims to maximize the equilibrium population size, or alternatively minimize the extinction risk, of a target fish species subject to a budget on the total cost of barrier mitigation. A case study involving a wild coho salmon (Oncorhynchus kisutch) population from the Tillamook basin, Oregon, USA is used to illustrate the benefits of our approach. We consider two different spawning adult dispersal patterns, river and reach level homing, as well as straying. Under density dependent population growth, we find that homing behavior type has a significant effect on barrier mitigation decisions. In particular, with reach homing, our model produces virtually the same population sizes as a more traditional barrier prioritization procedure designed to maximize accessible habitat. With river homing, however, we find that it is not necessary to remove all barriers in order to maximize equilibrium population size. Indeed, a stochastic version of our model reveals that removing all barriers actually results in a marginal increase in quasi-extinction risk. We hypothesize that this is due to a population thinning effect of barriers, resulting in a surplus of recruits in areas of low spawner density. Our findings highlights the importance of considering spatiotemporal fish population dynamics in river connectivity restoration planning. By adding greater biological realism, models such as ours can help conservation managers to more strategically allocate limited resources, resulting in both cost savings and improved population status for a focal species.

Design trade‐offs in rights‐based management of small‐scale fisheries

Small-scale fisheries collectively have a large ecological footprint and are key sources of food security, especially in developing countries. Many of the data-intensive approaches to fishery management are infeasible in these fisheries, but a strategy that has emerged to overcome these challenges is the establishment of territorial user rights for fisheries (TURFs). In this approach, exclusive fishing zones are established for groups of stakeholders, which eliminates the race to fish with other groups. A key challenge, however, is setting the size of TURFs-too large and the number of stakeholders sharing them impedes collective action, and too small and the movement of target fish species in and out of the TURFs effectively removes the community's exclusive access. We assessed the size of 137 TURFs from across the globe relative to this design challenge by applying theoretical models that predict their performance. We estimated that roughly two-thirds of these TURFs were sized ideally to overcome the challenges posed by resource movement and fisher group size. However, for most of the remaining TURFs, all possible sizes were either too small to overcome the resource-movement challenge or too large to overcome the collective action challenge. Our results suggest these fisheries, which target mobile species in densely populated regions, may need additional interventions to be successful.

Fish passage hydrodynamics: insights into overcoming migration challenges for small-bodied fish

The modification and utilization of rivers in regions where small-bodied diadromous fish are prevalent has largely occurred without fully understanding the migration behaviour of these species. As a result, existing in-stream structures often prevent or restrict migration. Current fish passage design guidance generally focuses on providing average hydrodynamic conditions within the range of known critical swimming velocities for target fish species. Considerable portions of discharge capacity must be sacrificed to achieve average cross-sectional water velocities that will allow passage of weak swimmers. Furthermore, because the hydrodynamic requirements for small-bodied species are poorly understood, successful passage is still not guaranteed even when average hydrodynamic design criteria are met. Ethohydraulic research is focused on how water flow influences fish behaviour and vice versa, by studying the interaction of fish with small-scale in-flow characteristics. We discuss how an ethohydraulic approach may improve fish passage design for small-bodied fish, such as țnanga/common galaxias (Galaxias maculatus), a widespread diadromous Southern Hemisphere species. The ethohydraulic approach is discussed in detail for culverts, a commonly found structure known to impede fish passage for many small-bodied species.

Line Fishing Methods of the Brahmaputra Valley

An investigation was carried on the availability of different types of fish hooks and liningmethods in the Brahmaputra valley with an objective to study the respective dimensions, seasonal variation, abundance, catch, cost, the variability of gears with the targeted fish species and their mode of operation. The identified fish hooks and lineused by the fishers of Assam can be classified into 10 different types under 2 major categories based on the principle of capture, design, and operational methods. Many of these gears were selective and the hook materials have a significant influence on the gear performance. The fish catch is composed of small fishes viz., C. punctatus, Puntius spp., Anabas testudineus, Eutropiichthys vacha; mid-sized fishes viz., Catla catla, Labeo rohita, Channa maruliusand bigger sized fishes viz., Wallago attu, Rita rita, Bagarius bagarius, Chitala chitalaand Notopterus notopterus. The fishes are caught on their commercial importance in terms of food, ornamental and sports perspectives. Most of these hooks are fabricated traditionally and except the ones being importedon recreational purposesin the region.

Assessment of catch composition and economic analysis of monofilament and multifilament under-meshed gears (Ngongongo) at Likoma Island, Lake Malawi

The study was conducted to assess catch composition and economic analysis of monofilament and multifilament under-meshed gillnets (Ngongongo) from March to April 2018 at Likoma Island, Lake Malawi. Catch efficiency for targeted fish species in monofilament gillnets showed that catch per unit effort (CPUE) was three times higher than that of multifilament gillnets for Copadichromis spp. (402.2 Kg, 43.3%), Opsaridium microcephulus (315.47 Kg, 34.6%), Rhamphocromis spp. (26.2 Kg, 2.8%), Bagrus meridionalis (21.6 Kg, 2.3%), Oreochromis karongae (40.7 Kg, 4.4%), Bathyclarias spp. (23.2 Kg, 2.5%), Dimidiochromis kiwinge ( 14.4Kg, 1.6%) among others. Catches for Copadichromis spp. comprised of 43% for both gillnet material type combined indicating the importance of this species in gillnet fishery in the district. Monofilament gillnet caught the highest number of fish (7569) while multifilament gillnet caught the least (5427). Again monofilament gillnet has the highest weight of fish (692.87kg) while multifilament has the least (238.22kg). T-test analysis showed that the weight of fish caught by monofilament and multifilament gillnets were significantly different from one another (p=0.000).The profitability performance non-motorized monofilament and multifilament gillnets canoe fisheries in Lake Malawi (Likoma) recorded profit margins at the end of the first year of operation with the minimum Return on Investment (ROI) of 58.9% and 34.4% respectively. On the other hand, the motorised monofilament and multifilament Gillnets canoe fisheries recorded loss 51.1% and 74.4% ROI. The study results point out to recommend for management interventions be put in place to manage the Lake Malawi fishery by imposing restrictions on effort, gear type and mesh sizes and access to illegal material.

Flow structure and fish passage performance of a brush-type fish way: a field study in the İyidere River, Turkey

The fish passage performance and flow structure of a brush fish pass were investigated at the İncirli Small Hydropower Plant on the İyidere River, located in the East Black Sea region of Turkey. The spatial distributions of velocity vectors, power velocity, Froude number and turbulent kinetic energy are presented. The flow is quasi-uniform and subcritical, which provides different migration corridors with favourable hydraulic conditions; importantly for the fish, these corridors continue through the complete fish pass. The flow–bristle interaction creates a reduced velocity and low-turbulence resting zones. In addition, the passage efficiency of the brush fish pass was assessed using passive integrated transponder telemetry. The results clearly showed that upstream passage efficiency differs between fish species: Salmo coruhensis performed better than Alburnoides fasciatus on the same fish passage. The passage efficiency for the target fish species S. coruhensis was calculated to be 82.4%. The data revealed that the brush fish passage provides passage for small-bodied fish (total body length &amp;lt;15cm) in a high-gradient channel with a slope of 10%. The monitoring data revealed that bristles as flexible hydraulic elements are beneficial for migrating fish.

Effects of turbulence and velocity on the movement behaviour of bighead carp (Hypophthalmichthys nobilis) in an experimental vertical slot fishway

The vertical slot fishway (VSF) plays a major role in protection and restoration of migratory fishes at many migratory barriers. However, the VSF design greatly depends on fish response to hydraulics and swimming behavior, which are key to the design of effective VSFs for target fish species. This study evaluated the effects of hydraulic characteristics on movement behavior of bighead carp (Hypophthalmichthys nobilis) by combining spatial hydraulic distributions with fish movement trajectories in an experimental VSF. Fish spent more transit times in ranges of velocity (V) with 0.15–0.45 m/s, turbulent kinetic energy (TKE) with 0.020–0.043 m2/s2, turbulent dissipation rate (TDR) with 0.020–0.065 m2/s3and strain rate (SR) with 2–7 s−1 under different discharges (18.0L/s and 26.0L/s), respectively. Correlation were found between fish transit times and hydraulic variables of velocity (V) (Q = 18.0 m/s: r = 0.397, P < 0.01; Q = 26.0 m/s: r = 0.407, P < 0.01), turbulent kinetic energy (TKE) (Q = 18.0 m/s: r = 0.476, P < 0.01; Q = 26.0 m/s: r = 0.469, P < 0.01). TKE and V were the key hydraulic parameters associated with the fish transit movement times in VSF. The results provided key hydraulic parameters for bighead carp movement in VSFs, which can serve as reference design for the future VSF and others fishway designs for this species.

Coral reef fish population in the western extremity of the Coral Triangle

The central and north west coast of Sabah lies along the western extremity of the Coral Triangle, within which lies several marine protected areas (MPAs). In this study we determined in situ coral reef fish populations in several localities along the west coast of Sabah, by exploring species abundance, richness and diversity of ten economically important fish species. The underwater surveys were conducted from May to December 2015. During this eight month period, surveys at each site were undertaken once every two months. Dives were conducted during the daylight hours. A total of 171 individuals from the targeted fish species were enumerated from the 349 still images and 220 minutes of video footage. Abundance was observed mainly in the semi-protected MPA (n=110) with only one fish species recorded with more than 2 individuals at protected MPA and unprotected sites. We observed a correlation between fish species richness and coral topographic complexity, with study sites at the semi-protected MPA having the most complex topography landscape, and accordingly recording the highest Shannon-Wiener index (H= 2.85). Higher abundance figures recorded at study sites in the unprotected MPA indicate that such areas could potentially become de facto MPAs. A long-term monitoring, assessment and evaluation of the multiple degrees of variables involved such as length-weight relationship, type of habitat, variation in depth, and species behaviour is recommended in order to understand better the relationship and dynamics between these variables.

Using redundant primer sets to detect multiple native Alaskan fish species from environmental DNA

Accurate and timely data regarding freshwater fish communities is important for informed decision-making by local, state, tribal, and federal land and resource managers; however, conducting traditional gear-based fish surveys can be an expensive and time-consuming process, particularly in remote areas, like those that characterize much of Alaska. To help address this challenge, we developed and tested five multi-species environmental DNA (eDNA) primer sets for the simultaneous detection of up to 37 target fish species in a single sample. Using these primer sets can reduce the cost and time needed to perform future studies of fish communities. Our results comparing multiple samples from multiple lakes and streams using multiple next-generation sequencing runs show the efficacy and reproducibility of these primers.

An experimental study on fish attraction using a fish barge model

Fish-collection and transportation systems (FCTS) have been introduced and applied as innovative approaches to facilitate fish passage in China for several years. The efficacy of FCTSs depends directly on the efficiency of the fish-guidance measures employed. In this study, the effects of three parameters—water flow, artificial lighting, and bubble curtains—on the attraction of mosquitofish (Gambusia affinis) was investigated using a fish barge model in a large pond. The experiment was conducted in two steps. First, a univariate experiment was performed, and then, a multivariate experiment using an orthogonal design was performed. Four different colors of light were tested: 1) yellow light (570 nm), 2) blue light (460 nm), 3) warm white light (3000 K), and 4) a weak light control group, whose illuminance belongs to the interval 0.001 lx to 0.3 lx. Supplementing water flow within the barge decreased the number of attracted fish (i.e., the number of the targeted fish species that appeared within 1.5 m of the barge model’s entrance) but increased the fish-collection ratio of the fish-collecting platform (i.e., the ratio of the number of attracted fish to the number of collected fish). Warm white light was shown to be significantly effective in attracting fish, while no obvious effect was observed in terms of the fish-collection ratio. The bubble curtain exhibited excellent fish-attraction efficacies, but also had no significant effect on the attraction and collection efficacy of the fish-collecting platform. During the day, the optimal combination for fish attraction was to have no water flow with a bubble curtain, while the optimal combination for fish collection was to have no water flow and no bubble curtain. During the night, the optimal combination for fish attraction was to have no water flow, no bubble curtain, and a warm white light, while the optimal combination for fish collection was to have water flow, no bubble curtain, and a weak light. This study tested the combined efficacies of various fish-guidance measures on a fish-collecting platform, thus providing experimental support for optimizing various fish-attraction measures and the application of these measures in FCTS projects.

Kuzey Ege Denizi’nde barbun uzatma ağlarında yakalanılan hedef dışı türlerin seçiciliği

The aim of this study is to determine the effects of red mullet gillnets that commonly used in Turkish waters on sustainability of non target fish species. For these purpose, surveys were realized with 18 - 20 - 22 mm nominal bar length red mullet gillnets between December 2008 and May 2010 along the north Aegean Sea coasts (5-30 m). SELECT method was used with five different model (Normal location, normal scale, log-normal, gamma and bi-modal) for evaluating selectivity parameters of non target fish species. Selectivity models were determined as bi-modal for Serranus scriba and Symphodus tinca , log normal for Scorpaena porcus and Spicara maena and gamma for Pagellus acarne . Optimum catch lengths and spread values and selectivity curves were given for 5 species. Results showed that use of a larger mesh size over the 22 mm mesh is important for ensuring stock sustainability of the non target fish species.

Stock delineation of the long-whiskered catfish, Sperata aor (Hamilton 1822), from River Ganga by using morphometrics

Long-term isolation of populations and interbreeding can lead to morphometric variations among fish populations. This study was conducted with the objective to delineate stock structure of Sperata aor on the basis of morphometric characters, using truss network of the fish body. In total, 407 S. aor samples were collected from the four sampling locations of the Ganga River, viz. Narora, Kanpur, Varanasi and Bhagalpur. In total, 28 truss distance measurements were created by joining 13 morphometric landmarks on the fish body. MANCOVA showed significant (P&amp;lt;0.001) morphological variance among the sampling locations for the target fish species. Univariate ANOVA showed significant (P&amp;lt;0.001) differences in each of the morphometric measurements among the fish from different sampling locations. Wilk’s lambda test of canonical discriminant function analysis showed significant (P&amp;lt;0.001) differences in morphometric measurements of the fish from all sampling locations. Discriminant function analysis using Jackknife (leave-one-out) cross-validation classification showed 87.5% correct classification of the individuals into their original populations. Mantel test showed an overall good correlation between the genetic and morphometric datasets in the selected fish species. The results of this study can be employed in formulating stock-specific management strategies for S. aor from River Ganga.

Evaluation of fish habitat suitability using a coupled ecohydraulic model: Habitat model selection and prediction

AbstractThe selection of an approach to evaluate habitat suitability for a specific fish or life stage has been a matter of concern in habitat quality modelling studies. This study has taken Jinshaia sinensis, a commercially valuable fish endemic to the Jinsha River, China, as the target fish species. One‐ and two‐dimensional hydrodynamic models were coupled and combined with fish habitat models for a middle reach of the Jinsha River. The resulting ecohydraulic model was used to predict the changes in hydrodynamics and spawning habitat suitability that resulted from the operation of an under‐construction reservoir downstream of the study area. The preference function (product, arithmetic mean, geometric mean, and minimum value) and fuzzy logic habitat evaluation methods were compared to predict the spawning habitat suitability of the fish. The model was validated using the numbers of spawning eggs, and the results show that both the arithmetic mean and fuzzy logic method can be used to predict spawning habitat suitability. The model predictions show that the hydrodynamics of the study area would be altered if the impoundment water level exceeded 969 m. During the spawning season, the spawning habitat suitability would increase from April to early June and has little change from early June to July under the impact of the reservoir impoundment. The optimal river discharge rate for fish spawning is ~3,500 m3/s, and this would not change after the reservoir begins operation. This research can benefit other regions that will be affected by planned dams by predicting the impacts of reservoir operation on fish habitat quality, and the results will help decision makers protect the health of rivers and the overall ecosystem.