Abundance Of Freshwater Fishes Research Articles

Status of Fish Biodiversity in the Sindphana River Dam Near Shirur Kasar, District Beed, Maharashtra, India

Fish biodiversity studies were undertaken from January 2012 to December 2012 to census commercially important fishes in the Sindphana Dam. The present paper deals with the variety and abundance of freshwater fishes in the Sindphana Dam near Shirur Kasar Dist. Beed [M.S] India. The results of the present investigation reveal the occurrence of 44 fish species belonging to 7 orders, 15 families, and 26 genera. Among the collected species order Cypriniformes was most dominant constituting 50% followed by order Siluriformes constituting 18%, order Perciformesconstituting 18 %, orders Osteoglossiformesand Synbranchiformes constituting 5% and orders Mugiliformesand Beloniformes constituting 2 %of the total fish species. Fish biodiversity indices species richness 44 in the total number of species (N0), 3.73 in Margalef’s index (R1), and 0.97 in the Menhinick index (R2). Species diversity was 0.47 in the Simpson index (), 1.16 in the Shannon-Weiner index (H’), 2.98 in abundant species (N1), and 2.80 in very abundant species (N2). Species evenness was 0.42 in (E1), 0.21 in (E2), 0.17 in (E3), 0.95 in (E4), and 0.97 in (E5). Bangladesh J. Zool. 51(2): 155-164, 2023

NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics.

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Temporal trends and determinants of fish biomass in two contrasting natural lake systems: insights from a spring long-term monitoring scheme

Freshwater fish declines are triggered by a suite of anthropogenic threats, including habitat degradation, climate and land use change, biological invasions, pollution and overfishing. Robust monitoring schemes are needed to understand and detect any effects of different factors on freshwater fish abundance and to be able to predict and respond to potential stressors. Here, we used standardized biomass-per-unit-effort (BPUE) data deriving from gillnet sampling over a 34-year period in the two Prespa Lakes and determined species trends using general additive models coupled with structural change models. Furthermore, the influence of seven environmental variables was assessed for each fish species using an analytical approach based on random forests. We showed that the total annual BPUE is increasing in Lake Mikri Prespa whereas it is stable in Megali Prespa and that the relative BPUE of introduced species in the former is increasing through the years. Differences in the lakes' trophic status were reflected in species trend patterns. Random forests showed that air temperature, the introduction of the invasiveLepomis gibbosus, predation and water management played a role in shaping species biomass in Mikri Prespa whereas abiotic factors are the main drivers of biomass changes in Megali Prespa. Our results provide empirical evidence on the importance of long-term monitoring in distinguishing between direct and indirect effects of large-scale stressors on fish abundance as well as insights towards sustaining the integrity of fish communities.

Relationships between Pacific salmon and aquatic and terrestrial ecosystems: implications for ecosystem-based management.

Pacific salmon influence temperate terrestrial and freshwater ecosystems through the dispersal of marine‐derived nutrients and ecosystem engineering of stream beds when spawning. They also support large fisheries, particularly along the west coast of North America. We provide a comprehensive synthesis of relationships between the densities of Pacific salmon and terrestrial and aquatic ecosystems, summarize the direction, shape, and magnitude of these relationships, and identify possible ecosystem‐based management indicators and benchmarks. We found 31 studies that provided 172 relationships between salmon density (or salmon abundance) and species abundance, species diversity, food provisioning, individual growth, concentration of marine‐derived isotopes, nutrient enhancement, phenology, and several other ecological responses. The most common published relationship was between salmon density and marine‐derived isotopes (40%), whereas very few relationships quantified ecosystem‐level responses (5%). Only 13% of all relationships tended to reach an asymptote (i.e., a saturating response) as salmon densities increased. The number of salmon killed by bears and the change in biomass of different stream invertebrate taxa between spawning and nonspawning seasons were relationships that usually reached saturation. Approximately 46% of all relationships were best described with linear or curved nonasymptotic models, indicating a lack of saturation. In contrast, 41% of data sets showed no relationship with salmon density or abundance, including many of the relationships with stream invertebrate and biofilm biomass density, marine‐derived isotope concentrations, or vegetation density. Bears required the highest densities of salmon to reach their maximum observed food consumption (i.e., 9.2 kg/m2 to reach the 90% threshold of the relationship’s asymptote), followed by freshwater fish abundance (90% threshold = 7.3 kg/m2 of salmon). Although the effects of salmon density on ecosystems are highly varied, it appears that several of these relationships, such as bear food consumption, could be used to develop indicators and benchmarks for ecosystem‐based fisheries management.

Species Composition, Seasonal Occurrence and Abundance of Freshwater Fishes in Ayeyarwady River Segment, Sagaing Region, Upper Myanmar

The study was carried out to assess the fish species composition, seasonal occurrence, and abundance at Ayeyarwady River segment, Sagaing Region, upper Myanmar from July 2017 to June 2018. A total number of 52 species of 37 genera distributed among 20 families and 10 orders of freshwater fishes were recorded during the study period. The highest composition of species was observed in the order Cypriniformes and the lowest in Osteoglossiformes, Anguliformes, Beloniformes and Tetraodontiformes . The highest number of species was recorded in October (cool season) and the lowest were noted in June (dry season) during the study period. The highest numbers of individuals was recorded in order Clupeiformes. According to relative abundance value, the four species were noted as very common (Vc), eight species were common (C), and the remaining 39 species were categorized as uncommon species (Uc). Out of the 51 species recorded, 25 species were encountered at every month and the total of five endemic species and one introduced species was observed during the study period.

Predicted climate change effects on European perch (Perca fluviatilis L.) - A case study from the Curonian Lagoon, south-eastern Baltic

Climate change is likely to increasingly impact estuarine fish populations. Changes in water temperature or salinity can have deleterious effects on fish growth and behaviour. A decrease in the abundance of freshwater fish in the northern areas of the Curonian Lagoon has been attributed to increased salinity of inflowing water from the Baltic Sea. Thus, this study investigated the effects of possible changes in environmental salinity and temperature on the growth and behaviour of perch (Perca fluviatilis L.). Laboratory experiments revealed that brackish water (salinity 3 and 6) has neither a negative nor a positive effect on growth rates among perch young-of-the-year, when compared to freshwater (salinity 0). In contrast, results from behavioural experiments demonstrated that perch prefer to remain in brackish water (salinity 6) when given a choice between brackish and freshwater, and in warm water (18 °C) when given a choice between warm and cold water (12 °C). For this reason, the temperature rather than the salinity of inflowing colder brackish water from the Baltic Sea will be the most likely driver of short-term changes in fish distribution in the Curonian Lagoon.

Contrasting effects of dams with and without reservoirs on the population density of an amphidromous goby in southwestern Japan

Dam construction affects the distribution and abundance of freshwater fishes, particularly for diadromous species. Amphidromous fishes spawn in rivers, and hatched larvae descend to the sea (or standing water body such as lakes) immediately after hatching, grow there typically for a few months, and then ascend rivers as small juveniles. Landlocked populations of amphidromous fishes above dams and their migration between dam reservoirs and inlet streams (landlocked migration) have often been reported. In these cases, population density in the inlet streams may be increased by dam reservoirs, owing to reduced migration distance, which results in higher return rates. On the other hand, dams without reservoirs do not promote landlocked migration and merely act as a barrier to their upstream migration, resulting in decreased population density. In this study, we examined such contrasting effects of dams with and without reservoirs on the population density of an amphidromous goby, Rhinogobius fluviatilis, in two river systems (the Shigenobu and Yoshino Rivers) of Shikoku Island, Japan. In the Shigenobu River, where more than 300 sediment-control dams and weirs (barriers without reservoirs) have been installed, our analysis showed that the goby density decreased sharply with increasing the number of barriers higher than or equal to 2 m. On the other hand, in the Yoshino River, where we investigated both landlocked populations above water storage dams (with reservoirs) and non-landlocked populations in tributaries without water storage dams, the analysis showed that the goby density increased with decreasing the distance from standing water body (i.e. the sea or dam reservoirs). Furthermore, monthly surveys at sites above and below a water storage dam showed that the recruitment of ascending juveniles above the dam was more abundant and seasonally earlier than that below the dam, probably owing to reduced migration distance and increased return rates. Our results have implications for understanding how dams alter natural distribution patterns of amphidromous fishes.

Aberturas del cordón de arena de la laguna costera imboassica (Estado de Rio de Janeiro, Brazil) no alteran la abundancia de los peces comerciales

La laguna Imboassica (estado de Rio de Janeiro), tuvo de 1993 a 2001 cuatro aberturas del cordón de arena que la separa del mar. Durante este perí­­odo fueron realizadas 28 colectas de peces, siendo 55.6% de las especies de valor comercialclasificada en guildas funcionales como: residentes en lagunas costeras (RLC), marina-dependientes (MD), visitantes marinas (VM) y de agua dulce (D). La captura por unidad de esfuerzo (CPUE) de las especies de interés comercial en los perí­­odos antes y después de las aberturas fue obtenida de acuerdo al tiempo y área de exposición de las redes. No hubo variaciones significativas en la abundancia de todas las guildas antes y después de las aberturas del cordón de arena. Fue observada una tendencia de aumento en la abundancia de individuos de las especies VM, RCL y MD en los perí­­odos posteriores a abertura del cordón de arena. Cuando este permaneció cerrado por aproximadamente tres aí­±os, fueron realizadas 21 colectas de peces, con aumento en la abundancia de dulcicolas y disminución de otras guildas (VM, RCL y MD). La producción pesquera de la laguna Imboassica es considerada baja y varia por la abertura y cierre del cordón arenoso.

Species Composition and Abundance of Freshwater Fishes in Selected Rivers of Johor, Malaysia

Species Composition and Abundance of Freshwater Fishes in Selected Rivers of Johor, Malaysia

Quantifying fish avoidance of small acoustic survey vessels in boreal lakes and reservoirs

AbstractMobile hydroacoustic surveys are increasingly used to assess the distribution and abundance of freshwater fish; yet, fish may avoid moving vessels, potentially introducing bias in these assessments. In this study, avoidance in boreal lakes and reservoirs was quantified by developing a simple method based on paired drift:drift (D:D) and drift:motor (D:M) transects. Two systems in eastern Manitoba, Canada were studied: Lac du Bonnet reservoir and Nopiming. Acoustic data were collected using a digital DTX echosounder (BioSonics, Seattle, WA, USA), with a downward facing 200‐kHz split‐beam transducer, deployed from 5.5‐m vessels (Boston Whalers) modified for acoustic research. An avoidance coefficient (Ac) was developed based on comparisons of acoustic fish densities while the vessel moved over the same transects by drifting, and by motoring at survey speeds. Ac did not differ significantly from 1 (no avoidance) at Nopiming (median of 0.81, n = 13), but did at Lac du Bonnet (median of 0.51, n = 31, P < 0.05). Variability in Ac was as high in transect pairs and was unrelated to fish depth (mean 6.9 m at Lac du Bonnet; 13.1 m at Nopiming) or survey speed (up to 3.70 m·s−1, 7 knots). Results indicated that fishes did not dive in the presence of the motoring vessel, nor was avoidance size‐based. We did not detect any evidence of fish attraction to our drifting vessel. Our results suggest that boat avoidance during acoustic surveys of shallow boreal lakes may vary in relatively similar water bodies but can be quantified experimentally.

Dams and Disease Triggers on the Lower Mekong River

Ongoing and proposed construction of several large hydropower dams along the mainstream Mekong River and various tributaries has created a number of unanswered environmental and societal questions for governments and communities in Cambodia, China, Lao PDR, Myanmar, Thailand, and Vietnam [1]–[3]. Most concern over the controversial dam-building projects focuses on the extent to which river health and food security will be affected negatively. Foremost, the 85 or more proposed dams threaten to reduce the diversity and abundance of freshwater fish, the major animal protein source for many of the 67 million inhabitants of the Mekong River basin [4]–[7].

Freshwater Fish Abundance and Distribution in the Orange River, South Africa

Freshwater Fish Abundance and Distribution in the Orange River, South Africa

Aquatic systems in and adjacent to Agulhas National Park with particular reference to the fish fauna

The study aimed to determine the distribution and relative abundance of freshwater fishes in and adjacent to Agulhas National Park. Fourteen fish species were collected during surveys carried out in the Heuningnes and Ratel river systems and a variety of endorheic pans from 2003 to 2005. Seven of the species are marine fishes tolerant of low salinity (Mugil cephalus, Liza richardsonii, Monodactylus falciformis, Caffrogobius gilchristi, Rhabdosargus holubi, Solea bleekeri, Gilchristella aestuaria) with the remaining seven species being primary freshwater fishes. Three are indigenous, including Pseudobarbus burchelli, Sandelia capensis, and Galaxias zebratus of which two morphological forms were recorded within Agulhas National Park. The remaining four species are invasive aliens (Cyprinus carpio, Lepomis macrochirus, Micropterus salmoides, Micropterus punctulatus). Classification using physico-chemical variables indicated four major wetland groups, with fishes occurring predominantly in the group comprising palustrine, lacustrine and riverine wetlands, and in one instance in a brackish endorheic pan. Management actions which should facilitate conservation of indigenous fishes in the Agulhas region are suggested.

Freshwater fishes of Golden Gate Highlands National Park

The study aimed to determine the distribution and relative abundance of freshwater fishes in the Golden Gate Highlands National Park. A total of 1778 fish specimens from three species were collected during surveys carried out in the Little Caledon River during 2002. The chubbyhead barb Barbus anoplus was the only indigenous species recorded, and comprised 99.5 of the total catch. Two of the three recorded species were alien {Cypnnus carpio, Oncorhynchus mykiss}. A further nine indigenous species could potentially occur within the park, though are unlikely to be permanent residents. Barriers formed by instream impoundments may prevent temporary immigration of indigenous fishes, but also limit the further spread of alien species in the park's rivers.

Impact of environmental change on the freshwater fish Fauna of Iraq

Natural and man‐made factors have shown the ability to change the freshwater fish environment in Iraq over the last 6000 years. Changes in climate were among the major natural factors that caused a significant alteration in the distribution and abundance of freshwater fish in Mesopotamia. However, man‐made factors contribute more to the impact on the freshwater system in Iraq and ultimately on the freshwater dwellings, e.g. fish. There are a number of industrial factors, such as water abstraction by dams, devegetation, heavy fishing, pollution and species introduction, that have played a major role in the destruction of the freshwater fish habitat in Iraq and as a result real and more effective conservation measures need to be proposed.

Species diversity and abundance of freshwater fishes in irrigation ditches around rice fields

The relationships between environmental variables, distribution of freshwater fishes and their diet were investigated at 40 sites on irrigation ditches for rice fields in central Japan. Multivariate analyses showed that fish species richness and diversity in ditches was high when fishes were able to easily invade the rice fields. Natural stream beds not covered by concrete had greater total number and biomass of fishes in irrigation ditches. The connection between ditches and rice fields was of secondary importance. Canonical correlation analysis indicated that the two principal fish community variables, abundance and diversity, were respectively represented by the presence of the minnow, Gnathopogon elongatus elongatus, and the absence of the loach, Misgurnus anguillicaudatus. Most fishes in the irrigation ditches predominantly preyed upon aquatic insects such as ephemeropteran nymphs, chironomid larvae and trichopteran larvae, but aerial insects and benthic algae were also fed upon by a few species. Small fishes (<4 cm SL) preyed more on chironomid and less on trichopteran larvae than large (≥4 cm SL) fishes. The diet overlap between species was extremely high for small fishes in ditches weakly connected with rice fields. The recent changes in rice fields and irrigation ditches to increase production efficiency has led to a decrease in fish diversity. For the coexistence of rice production and fish diversity in rice areas, a new irrigation system, where fishes can easily invade rice fields and where plenty of invertebrates are available for fishes, should be developed.

Freshwater fishes of Tsitsikamma National Park

This study aimed to determine the distribution and relative abundance of freshwater fishes in the Tsitsikamma National Park. Fish assemblages in six river systems were sampled in 2001, with a total of 323 fish from eight species recorded. Indigenous fish collected included four freshwater species (Pseudobarbus afer, Pseudobarbus tenuis, Sandelia capensis, Anguilla mossambica), three estuarine species (Monodactylus falciformis, Caffrogobius gilchristi, Myxus capensis), and one alien (Micropterus salmoides). One additional indigenous species (Galaxias zebratus) and two aliens (Salmo trutta, Oncorhynchus mykiss) could potentially occur within the park. The topography and locality of the park presents a unique opportunity to meaningfully conserve the endangered P. tenuis as well as other fish characteristic of the eastern reaches of the Cape Floristic Region. Management action is required to minimise opportunities for further establishment and spread of alien fish species and to conserve indigenous fish assemblages within the park.

Freshwater fish of the Wilderness National Park

The study aimed to determine the distribution and relative abundance of freshwater fish in the Wilderness National Park. Fish assemblages in the Touw and Duiwe rivers were sampled in 1997 and 1998, with a total of 327 fish from nine species recorded. Indigenous species included two freshwater species (Pseudobarbus afer, Sandelia capensis), two catadromous species (Anguilla mossambicus, Myxus capensis), and two estuarine species (Monodactylusfalciformis, Caffrogobius multifasciatus). Three of the nine recorded species were alien (Micropterus dolomieu, Micropterus salmoides, Gambusia affinis), with the Micropterus spp., in particular, likely to have a substantial negative influence on indigenous species. A further one indigenous species, two translocated indigenous species, and five estuarine species could potentially be recorded in these rivers. River catchment management actions to restore perennial flow to the Duiwe River, to prevent the attenuation of floods, and to prevent further establishment and spread of alien and translocated biota are required to conserve indigenous fish assemblages.

FRESHWATER FISH OF THE ADDO ELEPHANT NATIONAL PARK

Summary This study aimed to determine the distribution and relative abundance of freshwater fish in the Addo Elephant National Park. A total of 1578 fish specimens of 12 species were collected during surveys carried out in the Sundays River and four tributaries during 1996 and 1997. The redfin minnow Pseudobarbus afer comprised 81.6% of the total catch. Length frequency analysis of P. afer populations indicated recent successful recruitment in several rivers. Differences between rivers in the concentrations of dissolved and suspended solids and pH are possible reasons for different species complements. These surveys show the distribution of P. afer and Barbus aeneus in the Eastern Cape Province to be wider than previously reported. Management action is required to minimise opportunities for further establishment and spread of alien and translocated fish species and to conserve indigenous fish assemblages within the Park.

Distribution and abundance of freshwater fish in New Zealand rivers

The distribution and abundance of fish at sites in 38 medium to large New Zealand rivers were examined. Fish density varied from 5 to 200 fish per 100 m2, with an average of 53 fish. Our study sites contained a greater species richness and abundance than records stored on the New Zealand Freshwater Fish Database, where the average density was 28 fish per 100 m2. The average number of species at the study sites was 5, compared to 3 in the national database. Comparison of first-pass catches with multiple-pass population estimates showed that there was no difference in capture probability between species and that on average 51% of the population was captured on the first pass. The diadromous habit of many native species, and their ability to penetrate inland, was an overwhelming influence on their distribution. There was little regional variation in species composition, apart from the presence or absence of three non- diadromous species. Two distinct fish communities were evident: lowland and upland. Lowland communities typically contained the highest density and diversity offish, whereas upland communities were dominated by one or two species. Many river sites were intermediate between lowland and upland, both in species composition and fish density, and showed a gradual reduction in abundance and change in community structure with elevation, as those fish less able to penetrate inland disappeared and non-diadromous species began to appear. Elevation was the most important discriminating factor, with physical habitat and