Abundance and Diversity of Fish Assemblages Along the River-Estuary Continuum in a Fluvially Dominated Southern African Coastal System

Nashima, Festus P.; Strydom, Nadine A.; Lamberth, Stephen J.

doi:10.1007/s12237-021-00926-1

Cited by 6 publications

(8 citation statements)

References 39 publications

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“…Over the eight-year study period, a total of 26,086 fish were caught, representing 30 species. According to the previous study by Nashima et al 40 , the majority of fish species belonged to the freshwater category (47%) based on estuarine associations, with 11 freshwater stragglers and three freshwater estuarine-opportunist species recorded. The estuarine category (20%) included one solely estuarine species, five estuarine and marine species, and no estuarine and freshwater or estuarine migrant species.…”

Section: Resultsmentioning

confidence: 88%

“…Other marine species, such as L. amia, C. capensis, L. aureti , and P. saltatrix , were only found up to the oligohaline zone (Table 2 ). Despite this, all other species, regardless of origin, were underrepresented in the Orange River Estuary continuum in terms of percentage occurrences, except for C. richardsonii 40 .…”

Section: Resultsmentioning

confidence: 92%

“…The estuarine category (20%) included one solely estuarine species, five estuarine and marine species, and no estuarine and freshwater or estuarine migrant species. The marine category (34%) included four marine stragglers, three marine estuarine-opportunists, and three marine estuarine-dependents 40 .…”

Section: Resultsmentioning

confidence: 99%

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Assessing the application of the revised Remane Model to fish species in a fluvially dominated cool-temperate southern African coastal system

Nashima

Strydom

Lamberth

2023

Sci Rep

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Estuaries are ecologically important areas which support a variety of aquatic species, particularly marine and estuarine fish species. This study represents a case study of the Orange River and Estuary (ORE) to understand patterns in fish assemblages and diversity trends that were compared to the revised Remane Model predictions in an estuary with poor marine fish species richness. A total of 30 species were recorded in the River continuum that comprised 14 freshwater, 10 marine and six estuarine species. Species diversity revealed seasonal variation in fish assemblages during the high-flow and low-flow seasons but not inter-annually. The results revealed that species diversity is lower in higher salinity areas when compared to low salinity areas. These patterns are consistent with the biogeographical trend of decreasing species richness along the South African coast from east to west, however, inconsistent with Remane predictions. The extremely low marine fish richness at its lower end and the extremely large freshwater influx at its upper end are the primary causes of the inconsistency. This may reflects the unsuitability of the Remane model for the Orange Estuary. In comparison to similar river-dominated South African estuaries, the ORE has a low marine species richness. When compared to more conventional South African estuaries, the ORE has a unique biotic environment with low fish species richness of estuarine-associated marine species adjacent to the Benguela upwelling zone and therefore the region does not offer suitable habitat for such species. As a result, the ORE is not a good candidate to test the Remane Model. The data does, however, confirm the left-hand part of the Remane model, which shows a decline in the fish species richness of freshwater fish species as salinity rises towards mesohaline and polyhaline levels.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 92%

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Assessing the application of the revised Remane Model to fish species in a fluvially dominated cool-temperate southern African coastal system

Nashima

Strydom

Lamberth

2023

Sci Rep

Self Cite

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show abstract

“…Other marine species, such as L. amia, Chelidonichthys capensis, L. aureti, and Pomatomus saltatrix, were only found up to the oligohaline zone (Table 2). Despite this, all other species, regardless of origin, were underrepresented in the Orange River Estuary in terms of percentage occurrences, except for C. richardsonii (Nashima et al 2021).…”

Section: Estuarine Species Association Along the River-estuarine Continuummentioning

confidence: 92%

“…Over the eight-year study period, a total of 26 086 sh were caught, representing 30 species. According to the previous study by Nashima et al (2021), the majority of sh species belongs to the freshwater category (47%) based on estuarine associations, with 11 freshwater stragglers and three freshwater estuarine-opportunist's species. The estuarine category (20%) included one solely estuarine species, ve estuarine and marine species, and no estuarine and freshwater or estuarine migrant species.…”

Section: Fish Species Compositionmentioning

confidence: 93%

Assessing the Rigidity of the River Continuum Concept to Fish Species in a Fluvially Dominated Southern African Coastal System

Nashima

Strydom

Lamberth

2021

Preprint

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A continuous gradient of physical and biological processes exists within a river system from headwaters to mouth, according to the River Continuum Concept. In this study, the River Continuum Concept was used to compare patterns in fish assemblages and diversity trends to Remane predictions. The findings show that species diversity is low near the estuary's mouth and increases upstream. While the presence of several marine and estuarine species increased species diversity upstream in the river due to the dominance of freshwater fishes, it decreased downstream due to the presence of several marine and estuarine species. These patterns are consistent with the biogeographical trend of decreasing species richness along the South African coast from east to west. Based on the findings of this study, the River Continuum Concept ignores plasticity, which is evident in species that use transitional waters. As a result, the concept is insufficiently valid for the Orange River Estuarine Continuum, and a new concept known as the “River-Estuarine Continuum” has been proposed.

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Composition and distribution of fish assemblages in a tropical river–estuarine continuum

Silva

Barros²,

Silva³

et al. 2023

Hydrobiologia

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Abundance and Diversity of Fish Assemblages Along the River-Estuary Continuum in a Fluvially Dominated Southern African Coastal System

Cited by 6 publications

References 39 publications

Assessing the application of the revised Remane Model to fish species in a fluvially dominated cool-temperate southern African coastal system

Assessing the application of the revised Remane Model to fish species in a fluvially dominated cool-temperate southern African coastal system

Assessing the Rigidity of the River Continuum Concept to Fish Species in a Fluvially Dominated Southern African Coastal System

Composition and distribution of fish assemblages in a tropical river–estuarine continuum

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