Occurrence Of Fish Species Research Articles

Extinction debt in lake fish due to river–lake disconnection

After habitat loss and fragmentation, some species may persist for some period, but eventually become extinct, resulting in the so-called extinction debt. Understanding extinction debt can help depict biodiversity change processes and prevent underestimating biodiversity loss in conservation practices. River-lake disconnection has reduced fish diversity in lakes within the middle and lower Yangtze River basin, and may cause extinction debt as well after river–lake disconnection, which has not been noticed so far. This study collected fish species occurrence data from the 1950s to 2020, along with data on lake area and disconnection time. Taxonomic (TD), functional (FD), and phylogenetic (PD) diversity indices were calculated and analyzed to test the hypothesis using three methods: time series analysis, equilibrium methods, and past habitat analysis. The results showed that extinction debt was detected in TD across all methods, whereas FD did not exhibit extinction debt and PD demonstrated the presence of extinction debt by time series analysis. Furthermore, the decline in TD correlated with both lake area and disconnection time, while PD decline was associated with disconnection time. These results revealed extinction debt in the taxonomic and phylogenetic diversity of fish due to river–lake disconnection, but not in functional traits. Our findings provided empirical evidence of extinction debt and emphasize the importance of considering long-term species loss when assessing the cumulative impacts of habitat loss and fragmentation.

Future invasion risk assessment of the peacock bass in Neotropical ecoregions: A conceptual and testable model

Protecting freshwater biodiversity from non-native invasive species and their impacts is crucial for minimising both regional and global deterioration of ecosystem services. The yellow peacock bass Cichla ocellaris, a predatory freshwater fish endemic to the Amazon region, has been translocated within several Neotropical ecoregions, exhibiting harmful effects on biodiversity. In order to facilitate the prioritization of management efforts, which are essential for defining conservation actions in extensive and diverse areas, we propose a risk assessment index that integrates multiple ecological and environmental variables within a comprehensive framework, here applied for C. ocellaris. By considering fish species richness, occurrence frequency, and climate suitability, our index provides a more nuanced understanding of invasion risks. Within regions categorized as high and very high risk, where ecological impacts of C. ocellaris have been extensively documented (e.g., the Southern and North-East Brazilian regions, as well as Central American and Caribbean ecoregions), numerous environments are increasingly conducive to the establishment of this invasive species, exacerbated by a surge in dam constructions. Our analysis projects a significant increase in suitable habitats by 5% to 6.5%, with Southern and Northeastern Brazil and Central America identified as critical zones. Thus, our reproducible risk assessment framework, which considers freshwater ecoregions as conservation units, not only directs effective resource allocation for control measures but also enhances our ability to predict and mitigate the ecological impacts of non-native species introductions, providing a valuable tool for both policymakers and conservationists.

Species on the move: Impacts of climate change on the spatial range of endemic fishes of the eco-sensitive semi-arid area of the Arabian Peninsula

Climate change is one of the most significant challenges worldwide in the Anthropocene, and it is predicted to importantly affect biological diversity, especially in freshwaters. Freshwater fishes are facing considerable global threats, particularly in eco-sensitive semi-arid to arid areas such as the Arabian Peninsula, which is considered a highly stressed region in the Middle East. Endemic species are believed to display a narrow range of traits, with rarity reflecting adaptation to specific environmental regimes, and they are thus highly sensitive to environmental disturbances. This study is the first attempt to map the occurrence of endemic freshwater fish species and predict the impact of climate change on their spatial range in the semi-arid area of the Arabian Peninsula using Species Distribution Modeling (SDM). We compared the present and future (2041–2060 and 2061–2080) climate niche for the species under various climatic scenarios. All global circulation models (GCMs) performed well in predicting the species' climatic niche (AUC ranging between 0.72 and 0.92). For certain species (Cyprinion acinaces, Garra buettikeri, Carasobarbus exulatus, Arabibarbus arabicus, and Cyprinion mhalense), variables associated with precipitation were more important than those related to temperature, while for others (Carasobarbus apoensis, G. sahilia, G tibanica, and Aphaniops kruppi), temperature-related variables were most important. Precipitation in the coldest quarter and in the driest quarter was the most sensitive variable for the predictions. The species showed distinct responses to climate change; seven were predicted to lose their climatically suitable habitats (losers) and are thus threatened and highly vulnerable to the effects of climate change, while two species were predicted to expand their range (winners). Regular monitoring of fish in the Arabian Peninsula is recommended to conserve endemic species and their ecosystems.

Environmental DNA metabarcoding reflects spatiotemporal fish community shifts in the Scheldt estuary

Estuarine ecosystems face increasing anthropogenic pressures, necessitating effective monitoring methods to mitigate their impacts on the biodiversity they harbour. The use of environmental DNA (eDNA) based detection methods is increasingly recognized as a promising tool to complement other, potentially invasive monitoring techniques. Integrating such eDNA analyses into monitoring frameworks for large ecosystems is still challenging and requires a deeper understanding of the scale and resolution at which eDNA patterns may offer insights in species presence and community composition space and time. The Scheldt estuary, characterized by its diverse habitats and complex currents, is one of the largest Western European tidal river systems. Until now, it remains challenging to obtain accurate information on fish communities living in and migrating through this ecosystem, consequently confining our knowledge to specific locations. To explore the potential of eDNA based monitoring, we simultaneously combine stow net fishing with eDNA metabarcoding, to assess spatiotemporal shifts in the Scheldt estuary's fish communities. In total, we detected 71 fish species in the estuary using eDNA metabarcoding, partly overlapping with historic fish community data gathered at the different study locations and in contrast to only 42 species using stow net fishing during the same survey period. Community compositions found by both detection methods varied among sampling locations, driven by a clear correlation to the salinity gradient. Limited effects of sampling depth and tide were observed on the eDNA metabarcoding data, allowing a significant reduction of the eDNA sampling effort for future eDNA fish monitoring campaigns in this study system. Our results further demonstrate that seasonal shifts in fish species occurrence can be detected using eDNA metabarcoding. Combining eDNA metabarcoding and stow net fishing further enhances our understanding of this vital waterway's diverse fish populations, allowing a higher resolution and more efficient monitoring strategy.

Recent Declining Trends in Pelagic Fish Catches in the Indian Ocean off Sri Lanka: Is Gill Oxygen Limitation Theory (GOLT) a Possible Explanation?

Recent trends in the pelagic fish landings of multi-day fishing fleets operated from Sri Lanka indicated significant declines in many fish species. Therefore, the present preliminary analysis investigates the perceptions of fishers on recent declining trends of pelagic fish landings from offshore areas of the Indian Ocean and further investigates whether the most common pelagic species landed in Sri Lanka conform to the gill oxygen limitation theory (GOLT) and to speculate GOLT as a possible explanation to such trends. According to the perceptions of 457 skippers of fishing vessels interviewed, such declines were possibly attributed to shifting of the areas of occurrence of pelagic fish species, making them less vulnerable to multi-day fishing vessels. As climate change and deoxygenation are major stressors affecting fish stocks, there is a challenging need for disentangling the impacts of these stressors from the effects of overfishing. The 18 most common pelagic fish species harvested from the Indian Ocean confirmed to the predictions from the GOLT, suggesting that shifting of these stocks could be due to deoxygenation which may have been triggered by increased sea surface and sub-surface temperatures. Therefore, fishery-independent surveys are needed to investigate the shifting of areas of occurrence of pelagic fishes in the Indian Ocean to understand their areas of occurrence the further investigate the relevance of GOLT for defining regional fisheries management plans.

Occurrence and Composition of Fish Species in Three Different Locations of the Ganga River

The freshwater ecosystem's health and fish diversity depend on natural and human interventions. The present investigation was carried out for one year to observe the present physicochemical parameters, fish composition, and abundance with diversity at three selected locations, i.e., A1, A2, and A3. Physico-chemical parameters were exceptionally suitable, and the limnological conditions were favorable for the growth and survival of biodiversity. 39 fish species belonging to 8 orders and 16 families were recorded, and cypriniformes was the most predominant order, followed by siluriformes. Simpson's Diversity Index (D) at site A1 was D=0.73, site A2 D=0.82, and site A3 D=0.87. The highest diversity was found at site A3 and the lowest at site A1. The second most dominant catch of exotics in the landing has adversely impacted the Indian major carps. There should be proper regulations and guidelines for the production and disposal of effluents as well as excessive fishing of indigenous aquatic fisheries.

Common processes drive metacommunity structure in freshwater fish

AbstractAimEnvironmental change affects metacommunity structure both directly—via abiotic factors and dispersal that affect species occurrence—and indirectly—via complex interactions among co‐occurring species. We examined how the three main metacommunity factors—environmental conditions, spatial processes and species associations—affect metacommunity structure and whether responses are predictable in real‐world systems by using novel methods to disentangle the drivers.LocationEastern Asia, northern Europe and central North America.Time periodContemporary.Major taxa studiedFreshwater fish.MethodsWe used a dataset of freshwater fish species occurrences in temperate lakes in three countries in different biogeographic regions. We analysed co‐occurrence patterns by using a joint species distribution model.ResultsWe demonstrated that environmental processes are the main drivers of species' distribution and diversity, suggesting that future climate change (anthropogenic alteration of abiotic factors) will heavily influence the structure of metacommunities. We also showed that spatial processes and species interactions mediated the influence of environmental processes, especially at the lake level.Main conclusionsOur results indicate that ongoing changes in metacommunity structure are modulated not only by the direct impacts of shifting abiotic factors but also by indirect effects of species interactions. Our global analysis indicates that even under the current high rate of environmental change, an identifiable set of underlying processes can be used to predict impacts of this change on metacommunity structure.

Increasing fish biodiversity in high elevation Albertan lakes in response to global environmental change over the past 50 years

IntroductionThe diversity of freshwater fishes is threatened by multiple environmental stressors, including climate change, alterations in land use, and introduction of non-native species. However, the quantification of temporal biodiversity in freshwater communities is limited. Here, we asked: i) how has alpha (species richness), beta (changes in freshwater species composition), and gamma diversity (total species diversity in a landscape) changed over time for lakes over a 50 year period?; and ii) What are the climatic, land use, and lake morphological drivers associated with higher diversity?MethodsWe assembled a database of fish species occurrence from 20 lakes across subalpine and alpine regions in Alberta from 1970-2019, in addition to lake morphological, climatic, and land use characteristics of the watersheds. ResultsWe observed an overall increase in alpha, beta, and gamma diversity from the 1970s to 2009s. However, all measures of diversity declined from 2010-2019. We found that more lakes and species assemblages were influenced by species gains, rather than species losses (with the exception of the last decade of sampling). DiscussionGenerally, we found that coolwater species were expanding and coldwater fishes were being lost throughout our study lakes. We highlight temporal heterogeneity in fish biodiversity responses to substantial environmental pressures in this region.

Temperate rocky reef fish community patterns in a coastal marine protected area (MPA) from northern Chile, utilizing remote underwater video cameras (RUVs)

Shallow water seascapes are complex systems, important for the life history and connectivity of many marine fish species. Remote Underwater Video cameras (RUVs) are an increasingly used, non-lethal technique able to record the occurrence of reef fish species with little disturbance. In this study, RUVs were installed in a Marine Protected Area (Chañaral Island, northern Chile, 29°2'S, 71°34'W) at three different depth strata (5, 10, 15 m) in three different habitats (sand and boulder, bedrock, and kelp forest) during October 2018, July 2021 and October 2021. The RUV system recorded a total of 20 species belonging to 16 families over 73.5 h of videotaping. The most recurrent fishes were damselfish Chromis crusma, Chilean sandperch Pinguipes chilensis, and marblefish Aplodactylus punctatus. There was a significant difference in fish assemblage composition among depth strata and seasons, but not among habitats. In July 2021 (austral winter) higher densities of small cryptobenthic fish (Helcogrammoides spp.) and medium-sized carnivorous Chirodactylus variegatus were detected, whereas P. chilensis was associated to the deeper stratum, and the herbivorous blenny Scartichthys viridis was related to the shallower depths, which is likely due to differences in the habitat structure and composition. Winter 2021 showed a higher species richness than in spring 2018, while the evenness (Pielou’s J’) was significantly higher in spring 2018 than winter/spring 2021. There was no other strong or consistent pattern, which suggests that most fish species use the entire depth gradient throughout the year. Finally, the results suggest that the use of RUVs for the estimation of biodiversity of rocky reef fishes is a cost-effective way to improve our understanding of nearshore community shifts in relation to environmental forcing.

Seasonal Occurrence of Fin Fish and Shell Fish Species Collected from the Arasalar Estuary, South East Coast of India

Seasonal Occurrence of Fin Fish and Shell Fish Species Collected from the Arasalar Estuary, South East Coast of India

Marine heatwaves affect breeding, diet and population size but not body condition of a range-edge little penguin colony

Significant marine heatwaves (MHWs) developed along the Western Australian coast in 1999 and 2011. Despite ecosystem losses and the southwards occurrence of many tropical fish species during and after the extreme MHW in 2011, there have been few studies on the effects of this MHW on seabirds, and no biological impacts related to the 1999 MHW have been reported. Using data from 1986-2019, we investigated the impacts of these events on breeding outcomes, body condition, diet composition, population size and mortality of little penguins on Penguin Island, in the temperate waters off Western Australia. Breeding outcomes were negatively impacted by the MHWs but body condition was not. Diet composition changed after the MHW, with sandy sprat Hyperlophus vittatus, the penguins’ typical major prey component, replaced by scaly mackerel Sardinella lemuru, a tropical fish species. Using an open robust design analysis that accounts for imperfect capture probabilities and staggered annual arrival and departure dates, we found that the population decreased by 80% following the 2011 MHW. Finally, more penguins died from starvation or from novel protozoal parasitic infections in 2011 and 2012 that were potentially introduced with the changed diet. This research highlights that the temporal and spatial influence of MHWs on seabirds depends on several factors. Furthermore, the magnitude and direction of a prey species’ response can be very localised and have significant impacts on avian predators. There are no obvious ways to mediate climate effects, but perhaps measures taken to reduce any synergistic impacts on prey abundance, particularly during MHW events, could be effective.

Habitat Use of Two Coral-Associated Cryptobenthic Gobiid Fishes (Family: Gobiidae) in the Southern Caribbean

Cryptobenthic fishes make up more than half of coral reef fish fauna and contribute greatly to coral reef trophodynamics and diversity. Because of their small size, they are easily overlooked and understudied. Some of them use corals as their habitat, but this association is not well understood. In the Caribbean, two common cryptobenthic gobies, Elacatinus evelynae and Coryphopterus lipernes, are usually observed residing on corals. In order to compare their habitat use, we investigated their distributions on a range of scleractinian host-coral species at three different depths (5, 10, and 15 m) at Curaçao, southern Caribbean. The numbers of both species were relatively low at 5 m. Furthermore, we investigated the relationship between fish size and depth and found that adult E. evelynae individuals were most common at 5 m depth and juveniles at 15 m depth. Novel host corals were found for both fish species. Taking host size into account, the gobies were most abundant on large coral colonies of two host species: E. evelynae on both Colpophyllia natans and Montastraea cavernosa, and C. lipernes only on C. natans. In summary, depth, host species, and host-colony size were found to be environmental factors that may determine the occurrence of both fish species.

Biogeographic patterns of the freshwater fishes from the state of Espírito Santo, eastern Brazil

ABSTRACT Biogeographic studies offer valuable insights into the origin, distribution and extinction of biodiversity. As such, this study aims to identify patterns of diversity and distribution of freshwater ichthyofauna in the state of Espírito Santo, to delineate biogeographic units and to propose a hypothesis of area relationship. A database containing information on 123 fish species occurrences was compiled to conduct analyses of species richness interpolation, bioregionalization, sampling effort interpolation, endemism, and a parsimony analysis of endemism. The sampling effort in Espírito Santo is uneven, with higher representativeness of sampling sites in the highlands. Six freshwater ichthyofauna bioregions were identified, along with three major areas of increased species richness, two consensus areas of endemism and three groups of basins. The central basins of the state are characterized by a marked presence of endemic species. The southern basins also stand out as an area of endemism and density of species typical of mountainous environments, such as loricariids; they are also characterized by a significant faunal overlap with the Rio Paraíba do Sul basin. The results of this biogeographic evaluation reinforce the perception that the watersheds of the state of Espírito Santo have a diverse and characteristic freshwater fish fauna, with well-defined biogeographic units.

A network-based approach to identifying correlations between phylogeny, morphological traits and occurrence of fish species in US river basins.

The complex network framework has been successfully used to model interactions between entities in Complex Systems in the Biological Sciences such as Proteomics, Genomics, Neuroscience, and Ecology. Networks of organisms at different spatial scales and in different ecosystems have provided insights into community assembly patterns and emergent properties of ecological systems. In the present work, we investigate two questions pertaining to fish species assembly rules in US river basins, a) if morphologically similar fish species also tend to be phylogenetically closer, and b) to what extent are co-occurring species that are phylogenetically close also morphologically similar? For the first question, we construct a network of Hydrologic Unit Code 8 (HUC8) regions as nodes with interaction strengths (edges) governed by the number of common species. For each of the modules of this network, which are found to be geographically separated, there is differential yet significant evidence that phylogenetic distance predicts morphological distance. For the second question, we construct and analyze nearest neighbor directed networks of species based on their morphological distances and phylogenetic distances. Through module detection on these networks and comparing the module-level mean phylogenetic distance and mean morphological distance with the number of basins of common occurrence of species in modules, we find that both phylogeny and morphology of species have significant roles in governing species co-occurrence, i.e. phylogenetically and morphologically distant species tend to co-exist more. In addition, between the two quantities (morphological distance and phylogentic distance), we find that morphological distance is a stronger determinant of species co-occurrences.

Protected and alien fish species in Polish lakes in 2014-2021

The occurrence, abundance, contribution, and size structure of protected and alien fish species were studied in 535 lakes situated in the northern and central parts of Poland in 2014-2021. We hypothesised that protected fish species, due to their status, would be rare in terms of abundance within certain lakes and/or less distributed. Four protected (Cottus poecilopus, Cobitis taenia, Misgurnus fossilis, and Rhodeus amarus) and eight alien species of fish (Ctenopharyngodon idella, Neogobius fluviatilis, Pseudorasbora parva, Acipenser baerii, Carassius gibelio, Ameiurus nebulosus, Hypophthalmichthys molitrix, and Cyprinus carpio) were identified in the studied lakes. Among protected species, the most common and frequent were R. amarus (65% of the studied lakes) and C. taenia (47% of the studied lakes). Other two species (C. poecilopus and M. fossilis) were recorded in one (0.2%) and 18 lakes (3.4%), respectively. Alien species were most often represented by C. gibelio, which occurred in 96 lakes (18% of the studied lakes). The presence of the remaining seven alien species was found in not many lakes (0.2-5.2% of the studied lakes). The abundance of C. gibelio was positively, while A. nebulosus was negatively related to the trophic state of lakes. Cobitis taenia was positively correlated with morphometric parameters of lakes (area and maximum depth). It came as surprise to us that some protected species were quite frequent and sometimes numerous, in contrast to the majority of alien species.

Seasonal variation and fish assemblage at Hakaluki Haor, Moulvibazar, Bangladesh

Wetlands in Bangladesh have undergone rapid degradation, primarily attributable to a range of factors. These factors include a marked increase in population, extensive water diversion for irrigation purposes, depletion of swamp forests, as well as other natural and anthropogenic causes. Hakaluki Haor is a vast wetland area located at North East in Bangladesh provides habitat for a diverse range of fish species. Due to natural and anthropogenic causes, fish species are declining in the Hakaluki Hoar. Fish species are declining primarily due to the utilization of harmful gear, the drying of beels every year, and overexploitation. The aim of the research was to assess the occurrence of various fish species in different seasons, their distribution, and conservation status. The research was carried out over the course of three seasons (summer, autumn, and winter) spanning from September 2017 to August 2018. The study utilized a mixed methodology approach to investigate the fish assemblage, which included examining the fish catch on boats along with the fish available in the nearest assembling center (fish market). In addition, the Shannon-Weaver index was followed to recognize the species diversity (H), richness (D), and Evenness (e). The research documented the presence of 64 fish species that were classified into 25 different genera, and 24 families across 10 orders. The order Cypriniformes was the most prevalent, constituting 42% of the total number of species identified. Other orders such as Siluriformes (22%), Perciformes (16%), Channiformes (6%), and Clupeiformes (5%) also demonstrated a considerable variety of fish species, although Cypriniformes had the highest dominance with 42% of the total species documented. Additionally, the research determined that among the complete assemblage of fish species identified, a total of 14 (18.88%) were classified as species facing threats. Based on the analysis, 6.25% are vulnerable, 12.5% endangered, and 3.12% are critically endangered as per IUCN Redlist. The research observed the Shannon-Weaver diversity (H), richness (D), and evenness (e) values for the fish species, which were found to be 2.47, 6.28, and 0.65, respectively. Moreover, participants retorted that the present income from fishing had decreased as compared to five years ago. The research finds that anthropogenic pressure is one of the key reasons to fish decline at Hakaluki Haor. According to the findings of the current research, community-based wetland conservation and management have been proposed as a viable and sustainable strategy for augmenting the fish species abundance.

Ecological traits and range size determine the occurrence of non-native fish species in a Neotropical floodplain

Ecological traits and range size determine the occurrence of non-native fish species in a Neotropical floodplain

First record of a barb, Pethia stoliczkana (Day) from Brahmaputra drainage, Assam, India

In this communication, occurrence of cyprinid fish species, Pethia stoliczkana (Day, 1871) has been reported for the first time from River Kopili, Brahmaputra drainage, Assam, India. A total number of eight specimens of the species were recorded from the river during the study. Conventional, as well as molecular taxonomic tools, confirmed the species as P. stoliczkana. The Mitogenome sequence of P. stoliczkana generated during the present study is the first such information from an Indian river.

New Report of Zu cristatus (Bonelli, 1819) in the Ionian Sea with an In-Depth Morphometrical Comparison with All Mediterranean Records

Monitoring the occurrence and distribution of rare fish species is essential, especially in a semi-closed basin such as the Mediterranean Sea. Biologically interesting species often represent fishing waste (being part of the by-catch) and therefore are not retained, leading to a huge gap in data collection. Here we report about the occurrence in the Ionian Sea of a Zu cristatus (Bonelli, 1819) specimen, a mesopelagic fish from the order Lampriformes considered rare in the whole Mediterranean basin. The sample was captured at a depth of 720 m off the coast of Noto (Sicily, Italy) by deep-sea longline fisheries. The biometrics and meristic data were compared with all the available data on specimens previously reported in the Mediterranean Sea. It is interesting to note that, among the few records in the literature, most reports mention a lower depth range for this species. In fact, it is quite known that juvenile specimens of Z. cristatus were frequently found in shallow waters, while information about the biology of the adult stage is scarce, indicating they would seem to prefer much deeper environments. Considering the difficulty to collect data on this rare fish, this contribution can help to improve the knowledge about its distribution.

Polychaetes and fish in a tropical bay in southeastern Brazil: Community concordance and influence of environmental variables

AbstractThe distribution of species depends on the relationship with other species and the influence of abiotic factors, modulated by long‐term evolutionary and biogeographic processes. Polychaetes and fish are important components of the biota that inhabit estuarine systems, coexisting in various habitats, although the relationship between these groups and their responses to environmental variables is poorly understood. This study aimed to assess the concordance between fish and polychaete communities in three zones (inner, middle, and outer) of a tropical bay and to determine environmental influences on these communities. The raised hypothesis is that benthic fish is associated with polychaetes and that these taxonomic groups respond differently to environmental conditions. Environmental characteristics were the main drivers determining the occurrence of fish species and polychaetes families; however, no consistent relationship was observed between fish and polychaetes. Sediment granulometry seems to be an essential driver in determining polychaetes and fish distribution while turbidity and phosphorus were also important for fish. The three zones differed in both water physicochemical and sediment (nutrients and granulometry) variables, which determined their uses by different fish and polychaetes species. Only one fish species, the gerreid Eucinostomus argenteus showed a weak but significant association with the Goniadidae and Spionidae polychaetes, which may be associated with similar environmental preferences of both taxa. The lack of a consistent relationship between benthic fish and their likely invertebrate prey may be associated with the small spatial scale of this study and the early fish life stages. Most fish in shallow coastal areas are still in their early life, feeding mainly on polychaetes and other benthic macroinvertebrates, and as the area is shallow, planktonic organisms may be included in their diet, thus relieving predation pressure on benthic organisms. These findings are important to unveil relationships among different taxonomical groups and their environment.