Fish Assemblages in a Small Mangrove System on Príncipe Island, Gulf of Guinea

Mangroves are highly productive ecosystems with complex adaptations to the transition between freshwater and sea. Mangroves function as nursery habitats for many organisms, providing protection and food sources for early developmental stages of crustaceans and fish, helping to maintain adjacent marine stocks. Mangroves in São Tomé and Príncipe remain poorly studied. This study addresses the importance of a small mangrove stand to ichthyofauna. The main goal of the study was to describe the fish assemblages of the Praia Salgada mangrove stand on Príncipe Island, and assess if variations in the season, tide, and mangrove zone affected fish distribution. Fish assemblages were sampled with mosquito nets during the rainy and dry seasons, and neap and spring tides, while environmental parameters such as water depth, temperature, pH, and salinity measurements were taken. The characteristics of the water column were affected by a sandbank that developed between sampling seasons, impacting on the dynamics of the water and biological exchanges between the mangrove stand and the adjacent marine environment. The study identified 14 fish species occurring in the Praia Salgada mangrove stand from a total of 772 specimens caught. Five species were recorded for the first time as occurring in the country’s mangrove areas, namely Caranx latus, Ethmalosa fimbriata, Mugil curema, Gobioides cf. africanus, and Citharus cf. linguatula. Most of the reported species are of commercial interest, and were predominantly juveniles, suggesting that the mangrove ecosystem provides a nursery function for several species. Some species revealed preferences for either the upper or lower part of the mangrove forest. The size of fish sampled tended to be bigger during the dry season, especially for the Mugilidae, Aplocheilichthys spilauchen and Gobiidae groups. E. fimbriata and Eucinostomus melanopterus displayed similar sizes between seasons. The average quantity of fish caught per day in the rainy season was three times higher than in the dry season. The fish species distribution in the mangrove stand varied significantly according to the season and mangrove zone. The overall results suggest that the Praia Salgada mangrove stand provides a nursery function for several of the studied fish species.

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Patterns of Fish Assemblage, Growth, and Diet Composition in a Tropical River between Two Cascading Hydropower Dams

International Journal of Ecology ◽

10.1155/2021/6652782 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Lee Nyanti ◽

Chen-Lin Soo ◽

Afina-Yian Chundi ◽

Elsa-Cordelia-Durie Lambat ◽

Alvinna Tram ◽

...

Keyword(s):

Fish Species ◽

Diet Composition ◽

Fish Assemblages ◽

Condition Factor ◽

Dry Season ◽

Growth Patterns ◽

Native Fish ◽

Wet Season ◽

Fish Samples ◽

The Impact

Construction of cascade dams has been shown to have impacts on fish assemblages and biodiversity. Yet, there is no literature on fish assemblages in the Murum River that connects the cascading Bakun and Murum dams in Sarawak, Malaysia. Hence, study on this modified ecosystem is necessitated to better understand the effects of the cascade dam construction on fish fauna. For this, fish samples were caught at five stations located along the river during both dry and wet seasons. Environmental parameters were taken concurrently with fish sampling. Length-weight relationship, condition factors, and diet composition of selected fish species in the river were also determined. The present study demonstrated that there are indications of the impact of cascading dams on the formation of a complex ecosystem in the Murum River, that is, changing from the shallow downstream of the Murum Dam to the deep transitional and inundated zone of the Bakun reservoir. The transitional zone in the Murum River exhibited the lowest fish species diversity, richness, and evenness during the dry season due to low pH and DO coupled with high turbidity. The biological indices improved when the water quality improved during the wet season. On the contrary, the diversity and evenness indices at the inundated tributary station decreased remarkably during the wet season, likely due to the migration of fish during the onset of the rainy season. This study showed that Barbonymus schwanenfeldii has a wider feeding habit which contributes to its higher distribution and abundance in the Murum River. The growth patterns of B. schwanenfeldii, Cyclocheilichthys apogon, Hampala macrolepidota, Lobocheilos ovalis, and Osteochilus enneaporos were better during wet than dry season. Overall, the condition factor of all native fish species in the Murum River was in poor to fair condition, whereas the exotic species, Oreochromis mossambicus, exhibited excellent condition (K value > 2) for both seasons. The increase in the number of O. mossambicus coupled with its high condition factor indicates biological intrusion and a potential threat to the native fish species in the Murum River. Continuous monitoring is essential to detect in-time risk issues associated with environmental degradation and biological invasion in this regulated and inundated river ecosystem.

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The Influence of Stream Barriers and The Hypothetical Origin of Highlands Fishes.

10.21203/rs.3.rs-601730/v1 ◽

2021 ◽

Author(s):

Nurul F.M. Fadzil ◽

Zarul H. Hashim ◽

Amir S. R. M. Sah ◽

Shahrul A. M. Sah ◽

Amirul A. A. Aziz ◽

...

Keyword(s):

Fish Species ◽

Fish Assemblages ◽

Fish Distribution ◽

Species Assemblages ◽

Fish Movement ◽

Chi Square ◽

Number Of Species ◽

The World ◽

Chi Square Test

Abstract Instream barriers such as waterfalls and man-made dams may result in distinct fish assemblages on both sides of the barriers. To determine the influence of these barriers on fish assemblages, a study was conducted in Sungai Enam that have substantial barriers including an 18-m high waterfall with 6.1% slope. Fish were captured using a backpack electrofishing gear together with scoop nets. Thirteen fish species from six families were recorded along this stream, but only Poropuntius smedleyi (Cyprinidae) can be found along the stream and the reach above the waterfall. Studies on a second site, Sungai Kooi, that has a 65m high and 90° slope waterfall, revealed eight fish species from three families, but only P. smedleyi and Devario regina (Cyprinidae) occurred above the waterfall. The number of species in both streams increases from upstream to downstream. A chi-square test revealed that the total number of species among reaches in Sungai Enam differed significantly. Fish species found above the waterfall are known to have no special adaptations to climb or jump over the barriers. Therefore, to explain their existence above the substantial waterfalls especially in Sungai Kooi, we proposed three hypotheses: (1) the world was once flooded and there was no limitation to fish distribution, (2) fish species assemblages were separated by land uplifting, and (3) there are other stream branches enabling fish movement into respective streams. Further studies are required to confirm these hypotheses.

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Assemblages of fish along a mangrove - mudflat gradient in temperate Australia

Marine and Freshwater Research ◽

10.1071/mf08124 ◽

2009 ◽

Vol 60 (1) ◽

pp. 1 ◽

Cited By ~ 14

Author(s):

Nicholas Leslie Payne ◽

Bronwyn May Gillanders

Keyword(s):

Fish Species ◽

Fish Assemblages ◽

Structural Complexity ◽

Fish Abundance ◽

Fish Distribution ◽

Individual Species ◽

Total Abundance ◽

Total Fish ◽

Abundance And Diversity ◽

Habitat Scale

Mangroves are considered to support rich assemblages of fish and invertebrates. Fishes inhabiting mangrove habitats and at various distances from mangroves across mudflats were sampled to: (1) compare fish assemblages between habitats; and (2) determine the influence of mangrove proximity on fish abundance and diversity in three southern Australian estuaries between November 2005 and January 2006. Based on their distribution, fish species were classified as mangrove residents, mudflat residents, generalists or rare species. The assemblage structure of fish in mangroves differed from assemblages 500 m away; however, neither total abundance nor species richness differed significantly between mangroves and mudflats. Mangrove residents and Aldrichetta forsteri (yellow-eyed mullet) displayed strong associations with mangrove habitats, whereas mudflat residents were associated with mudflat habitats. No other fish groups or individual species occurred in higher abundances in either habitat. Total fish abundance, mangrove residents and A. forsteri were positively correlated with pneumatophore density, indicating that the structural complexity of the mangroves might influence the distributions of certain fish species. The current study demonstrated that mangrove habitats in temperate Australia support no greater abundance or diversity of fish than adjacent mudflat habitats and that mangrove proximity does not influence fish distribution at a habitat scale.

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Mangrove fish of São Tomé Island (Gulf of Guinea): new occurrences and habitat usage

Marine and Freshwater Research ◽

10.1071/mf15392 ◽

2017 ◽

Vol 68 (1) ◽

pp. 123 ◽

Cited By ~ 5

Author(s):

P. M. Félix ◽

P. Chainho ◽

R. F. Lima ◽

J. L. Costa ◽

A. J. Almeida ◽

...

Keyword(s):

Fish Species ◽

Environmental Parameters ◽

First Record ◽

West African ◽

Fishing Gear ◽

Gulf Of Guinea ◽

Resident Species ◽

Sao Tome And Principe ◽

Habitat Usage ◽

New Occurrences

Mangroves are recognised as important nursery and feeding areas for resident and inshore fish species. However, the importance of West African mangroves to the life cycle of fish communities remains poorly studied. The present study is the first record of fish species in tropical insular mangroves for this region and its aim was to assess habitat usage by fish species. Two mangroves of São Tomé Island (Praia das Conchas and Malanza) were sampled with a multihabitat approach and using different fishing gear to maximise the diversity of fish species collected. Several environmental parameters were also measured. Both mangroves are nursery and opportunistic feeding grounds for fish species, as well as settlement areas for resident species. The highest number of both juveniles and adults (inshore and residents) was observed at the Malanza mangrove, which is also the largest and has the highest habitat heterogeneity. Four new occurrences were reported for the São Tomé and Principe area, namely Pomadasys jubelini, Bostrychus africanus, Dalophis cephalopeltis and the introduced species Oreochromis mossambicus.

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Longitudinal structure of fish assemblages in a minimally disrupted stream

Biologia ◽

10.2478/s11756-011-0097-z ◽

2011 ◽

Vol 66 (5) ◽

Cited By ~ 4

Author(s):

Ladislav Pekárik ◽

Miroslav Švátora ◽

Jaroslav Černý ◽

Ján Koščo

Keyword(s):

Correspondence Analysis ◽

Fish Species ◽

Western Europe ◽

Fish Assemblages ◽

Detrended Correspondence Analysis ◽

Environmental Parameters ◽

Distribution Patterns ◽

Longitudinal Distribution ◽

Important Species ◽

Ordination Method

AbstractThe longitudinal distribution patterns of fish species are affected by both natural and anthropogenic variables. The role of these factors on the formation of species assemblages is well documented in North America and Western Europe, but detailed information is lacking from Central and Eastern Europe, and the Carpathian region especially. Therefore, we examined the structure of fish assemblages in response to six key environmental parameters in a natural stream system (Udava stream basin, Slovakia). We used the indirect ordination method of gradient analysis (Detrended Correspondence Analysis, DCA) to analyse the species groups and their connections to the sampled sites and to recognize the strongest gradient of assemblage composition. Subsequently, we used the direct ordination method (Canonical Correspondence Analysis, CCA) to identify the strongest gradients in relation to selected variables. Two major gradients were identified that follow the upstream-downstream pattern of fish communities and three variables (distance from source, depth and site slope) are correlated with the first CCA axis (P < 0.05) and two variables (depth and vegetation cover) are correlated with the second CCA axis (P < 0.05). We assume that these factors influence the temperature and the amount of dissolved oxygen that can cause oxygen and temperature stress to intolerant species (e.g., salmonids). Based on these results, we assume that the economically important species, brown trout and grayling, are not native to the stream basin and this status is only the consequence of natural factors. Furthermore, the results suggest that the Udava stream offers favourable conditions for fish species distribution — a view supported by the high variability of particular variables within the proposed model.

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Spatiotemporal variation in wetland fish assemblages in the Western Ghats region of India

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2018023 ◽

2018 ◽

pp. 35

Author(s):

Archis R. Grubh ◽

Kirk O. Winemiller

Keyword(s):

Habitat Selection ◽

Western Ghats ◽

Fish Assemblages ◽

Environmental Parameters ◽

Wetland Hydrology ◽

Fish Population ◽

Dry Season ◽

Assemblage Structure ◽

Peninsular India ◽

The Western Ghats

The Western Ghats region of peninsular India contains high diversity of freshwater fishes that support artisanal fisheries, but no studies to date have investigated fish assemblages of the region's extensive wetlands. This study examined fish population densities and the structure of local species assemblages in pools of the Periyakulam wetland of the Western Ghats. From 2000 to 2001, fishes and local abiotic environmental parameters were surveyed during three periods with contrasting rainfall (dry, major wet, minor wet). We hypothesized that fish density would be higher during the dry season when aquatic habitat is reduced, and that local assemblage structure would be strongly associated with habitat conditions. Total fish densities were higher during the dry season, but the magnitude of seasonal change was relatively low, and this apparently was because changes in water depth were minimal due to operation of sluice gates that control wetland hydrology. Chanda nama, Pseudetroplus maculatus, Rasbora daniconius, and Danio aequipinnatus were dominant species in most habitats during all three seasons. Multivariate ordinations revealed strong associations between assemblage structure and habitats based on vegetation cover. Local assemblages in shallow-vegetated habitats varied seasonally in association with gradients of rainfall and water quality parameters. Spatial variation of local fish assemblages in the Periyakulam wetland appears to be maintained by species-specific habitat selection. Although hydrologic regulation probably has reduced seasonal variation in the structure of local assemblages, seasonal differences still occur and appear to be caused by species differences with regard to periods of reproduction, recruitment, dispersal and habitat selection.

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Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

Reviews in Fish Biology and Fisheries ◽

10.1007/s11160-021-09648-w ◽

2021 ◽

Author(s):

Mayara P. Neves ◽

Pavel Kratina ◽

Rosilene L. Delariva ◽

J. Iwan Jones ◽

Clarice B. Fialho

Keyword(s):

Seasonal Variation ◽

Fish Species ◽

Resource Availability ◽

Seasonal Changes ◽

Dry Season ◽

Diet Overlap ◽

Isotopic Niche ◽

Neotropical Streams ◽

Feeding Plasticity ◽

The Impact

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.

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Description of the larva of Bromeliagrion rehni (Odonata: Coenagrionidae) with bionomic notes concerning its phytotelmic habitat in central Amazonas, Brazil

Revista Brasileira de Zoologia ◽

10.1590/s0101-81752008000300012 ◽

2008 ◽

Vol 25 (3) ◽

pp. 479-486 ◽

Cited By ~ 2

Author(s):

Sharlene R. da S. Torreias ◽

Ulisses G. Neiss ◽

Neusa Hamada ◽

Ruth L. Ferreira-Keppler ◽

Frederico A.A. Lencioni

Keyword(s):

Rainy Season ◽

Environmental Parameters ◽

Dry Season ◽

Stage Larva ◽

Water Volume ◽

Apical Region ◽

Last Stage ◽

First Time ◽

The Relationship

The last-stage larva of Bromeliagrion rehni Garrison in De Marmels & Garrison, 2005 is described and illustrated and bionomics and habitat information on this species are provided. The study was conducted in the Reserva Florestal Adolpho Ducke, located near Manaus, state of Amazonas, Brazil.Twelve samplings were done between April, 2003 and April, 2005: six in the rainy season and six in the dry season. In each sampling month, 12 bromeliads (Guzmania brasiliensis Ule, 1907, Bromeliaceae) were collected, six of which were terrestrial and six epiphytic, yielding144 samples. A total of 75 specimens of B. rehni were collected. The relationship between larval B. rehni abundance and the measured environmental parameters (volume (ml), pH, season and stratum) was significant (ANCOVA, F = 5.296, d.f. = 130, p < 0.001). Larvae were most abundant in the rainy season (p < 0.01) and water volume was positively related to the abundance of B. rehni. Larvae of B. rehni can be distinguished from those of B. fernandezianum (the only species in the genus with described larvae) by the number of setae in the prementum and by the color of the apical region of the femur. The association of this species with phytotelmata of G. brasiliensis is reported here for the first time.

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Regional and Seasonal Differences in Species Composition and Trophic Groups for Tidepool Fishes of a Western Pacific Island – Taiwan

ILMU KELAUTAN Indonesian Journal of Marine Sciences ◽

10.14710/ik.ijms.23.1.1-18 ◽

2018 ◽

Vol 23 (1) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Colin K. C. Wen ◽

Li-Shu Chen ◽

Kwang-Tsao Shao

Keyword(s):

Species Composition ◽

Fish Species ◽

Fish Assemblages ◽

Coastal Development ◽

Species Number ◽

Pacific Region ◽

Trophic Groups ◽

Species Numbers ◽

Intertidal Fish ◽

Intertidal Fishes

Spatial and temporal variations in the species composition of assemblages are common in many marine organisms, including fishes. Variations in the fish species composition of subtidal coral reefs have been well documented, however much less is known about such differences for intertidal fish assemblages. This is surprising, given that intertidal fishes are more vulnerable to terrestrial human disturbances. It is critical to evaluate the ecology and biology of intertidal fishes before they are severely impacted by coastal development, especially in developing countries such as those in the tropical western Pacific region where coastal development is rapidly increasing. In this study, we investigated the species composition, abundance, biomass and species number (richness) for intertidal fish assemblages in subtropical (northern) and tropical (southern) Taiwan across four seasons by collecting fishes from tidepools using clove oil. We also examined the gut contents of collected fishes to identify their trophic functional groups in order to investigate regional and seasonal variations for different trophic groups. We found significant differences in the species composition of tidepool fish assemblages between subtropical and tropical Taiwan. Bathygobius fuscus, Abudefduf vaigiensis and Istiblennius dussumieri were dominant species in subtropical Taiwan, whereas Bathygobius coalitus, Abudefduf septemfasciatus and Istiblennius lineatus were dominant in tropical Taiwan. Other species such as Bathygobius cocosensis, Abudefduf sordidus and Istiblennius edentulus were common in both regions. For trophic groups, omnivores and detritivores had or showed trends towards higher species numbers and abundances in the subtropical region, whereas herbivores, planktivores and general carnivores had or showed trends towards higher species numbers and biomass in the tropical region. Overall, many intertidal fish species and trophic groups showed differences in abundance, biomass and species number between subtropical and tropical Taiwan. Further studies on large scale geographical gradients in trophic groups and species compositions in the Indo-west Pacific region are encouraged to assist with ecosystem monitoring and assessment. Keywords: Intertidal fishes, spatio-temporal pattern, feeding guild, diet

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Performance of a pool-and-weir fish pass for small bottom-dwelling freshwater fish species in a regulated lowland river

Animal Biology ◽

10.1163/157075607782232134 ◽

2007 ◽

Vol 57 (4) ◽

pp. 423-432 ◽

Cited By ~ 13

Author(s):

Evelien Maerten ◽

Marcel Eens ◽

Guy Knaepkens

Keyword(s):

Freshwater Fish ◽

Fish Species ◽

Fish Assemblages ◽

Regulated River ◽

Lowland River ◽

Stone Loach ◽

Spined Loach ◽

Freshwater Fish Species ◽

Cottus Gobio ◽

Fish Pass

AbstractAlthough small benthic freshwater fish species are an important biological component of fish assemblages and free instream movement is indispensable for their survival, they are often neglected in fish pass performance studies. In this study, a capture-mark-recapture approach was used to assess whether small bottom-dwelling species, including gudgeon (Gobio gobio), stone loach (Barbatula barbatula), spined loach (Cobitis taenia) and bullhead (Cottus gobio), were able to cross a pool-and-weir fish pass in a regulated lowland river. Some tagged individuals of stone loach (18%), gudgeon (7%) and spined loach (2%) managed to successfully ascend the fish pass under study, despite the fact that water velocity levels in the different overflows of the facility (between 0.55-1.22 m/s) exceeded the critical swimming speed of all three species. Although this suggests that a pool-and-weir fish pass is a able to facilitate upstream movement of some small benthic species in a regulated river, more detailed research incorporating advanced tagging and retrieving techniques is necessary.

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