A survey of the ichthyofauna in the Noetsie Estuary, Western Cape Province, South Africa

The fish assemblage in the Noetsie Estuary, a temporarily open and closed estuary on the southern coast of South Africa, was sampled using multiple gears. A total of 12 species from 8 families were recorded. Collectively, estuarine-dependent marine species dominated seine net catches numerically and in terms of biomass for both sampling seasons. Estuarine round herring (Gilchristella aestuaria) was numerically the dominant species in late summer, while juvenile Mugilidae dominated catches in winter. Size class distributions of various fish species indicate that the estuary both serves a nursery function for important euryhaline marine species and supports estuarine resident taxa. Application of the Estuarine Fish Community Index indicates the ecological condition of the estuary to be ‘good’. This study contributes to the species list for the estuary while also reporting the presence of an alien invasive freshwater species, Gambusia affinis. Recommendations include the development of a management plan and the formalisation of an estuarine management committee.Conservation implications: The Noetsie Estuary serves a nursery function for important euryhaline marine species, while supporting healthy populations of estuarine resident taxa. The presence of one alien invasive fish species is documented with potential implications for the conservation of biodiversity in the estuary.

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Fish communities of the Wilderness Lakes System in the southern Cape, South Africa

Koedoe ◽

10.4102/koedoe.v58i1.1364 ◽

2016 ◽

Vol 58 (1) ◽

Cited By ~ 2

Author(s):

Alexis A. Olds ◽

Nicola C. James ◽

M. Kyle S. Smith ◽

Olaf L.F. Weyl

Keyword(s):

South Africa ◽

Key Management ◽

Mouth Opening ◽

Marine Species ◽

Freshwater Species ◽

Sediment Removal ◽

Management Actions ◽

System A ◽

Artificial Mouth ◽

Estuarine Resident

The Wilderness Lakes System, a temporarily open and closed estuary with three associated lakes situated in the southern Cape region of South Africa, was sampled using a range of sampling gears to assess the fish community. A total of 25 species were sampled throughout the system, with the highest diversity in the Touw Estuary (23 species) and the lowest in Langvlei (11 species). Estuary-associated marine species (13 species) dominated species richness with smaller proportions of estuarine resident (7 species), freshwater (3 species) and catadromous species (2 species). Estuarine resident species dominated the catch numerically. The size–class distribution of euryhaline marine species indicated that upon entering the Touw Estuary as juveniles, the fish move up the system towards Rondevlei where they appear to remain. Three freshwater species were recorded in the system, all of which are alien to the Wilderness Lakes System. Decreasing salinity in the upper lakes appears to be a driving factor in the distribution and increasing abundance of the freshwater fishes. Sampling followed a drought, with the system experiencing substantially increased levels of mouth closure compared to a similar study conducted in the 1980s. The timing of mouth opening and the degree of connectivity between the lakes influence the nursery function of the system as a whole. Management actions need to focus on improving ecological functioning of this system, in particular how mouth opening is managed, to facilitate nursery function and limit the establishment of invasive species.Conservation implications: Key management actions are required to improve fish recruitment potential into and within the system. These include maintenance of adequate marine inflow through adherence to artificial mouth breaching protocols and improving connectivity between the lakes through sediment removal from localised deposition points within the connecting channels.

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Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa

Koedoe ◽

10.4102/koedoe.v54i1.1059 ◽

2012 ◽

Vol 54 (1) ◽

Cited By ~ 4

Author(s):

Jan A. Venter ◽

Bruce Q. Mann

Keyword(s):

South Africa ◽

Law Enforcement ◽

Fish Species ◽

Protected Area ◽

Surf Zone ◽

Marine Protected Area ◽

Fish Populations ◽

Estuarine Fish ◽

Catch Per Unit Effort ◽

Preliminary Assessment

A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

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Occurrence and distribution of fish in rivers of Latvia

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.2478/v10046-011-0019-z ◽

2011 ◽

Vol 65 (3-4) ◽

pp. 57-66 ◽

Cited By ~ 1

Author(s):

Jānis Birzaks ◽

Ēriks Aleksejevs ◽

Māris Strūgis

Keyword(s):

Fish Species ◽

Field Research ◽

Life Cycles ◽

Freshwater Species ◽

Species List ◽

Fishery Data ◽

Distribution Of Fish ◽

New Fish Species ◽

Lamprey Species ◽

Diadromous Species

Occurrence and distribution of fish in rivers of Latvia This publication is a review of data on fish and lamprey species found in 435 of Latvia's rivers and related reservoirs. A total of 43 fish species and three lamprey species, whose life cycles are, at least in part, associated with rivers, have been recorded. These can be divided into freshwater species and diadromous species. Differences between chronologically older publications and records collected since 1990 on fish occurrence are examined. Since 1990, the intensity of study of Latvia's rivers has increased, which is the reason for changes in the conception of the distribution and occurrence of fish species. The authors propose a new fish species list for Latvia's rivers, based on the newest field research and fishery data. The species included in list were caught in research trips during the period 1990 - 2010, or their capture was confirmed by an expert.

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Three new species of Gladiolus (Iridaceae) from South Africa, a major range extension for G. rubellus and taxonomic notes for the genus in southern and tropical Africa

Bothalia ◽

10.4102/abc.v39i1.227 ◽

2009 ◽

Vol 39 (1) ◽

pp. 37-45 ◽

Cited By ~ 4

Author(s):

J. C. Manning ◽

P. Goldblatt

Keyword(s):

South Africa ◽

New Species ◽

Southern Africa ◽

Late Summer ◽

First Record ◽

Range Extension ◽

Western Cape ◽

Tropical Africa ◽

Three New Species

Three new species of Gladiolus L. are described from South Africa. G. dolichosiphon is the second known member of series Blandus from the mountains of the Little Karoo in Western Cape, and is distinguished from other members of the long tubed, pink-flowered G. carneus complex by its 5 or 6 linear leaves, creamy pink to salmon flowers with a tube 30-50 mm long and longer than the dorsal tepal, and its late summer flowering. G. karooicus from the Klein Roggeveld and the northern foothills of the Witteberg, is a spring-flowering species allied to G. permeabilis but has bright, canary-yellow flowers with the lower part of the lower tepals involute and conspicuously auriculate. G. reginae is an edaphic endemic of the Sekhuk- huneland Centre of Floristic Endemism in Mpumalanga, and flowers in autumn. It is evidently a glabrous member of section Densiflorus series Scabridus, distinguished by its long-tubed flowers, streaked with red on the lower tepals and blotched with red in the throat. Anomalously, however, it has the tubular inner bracts and large capsules diagnostic of section Ophiolyza series Oppositiflorus. A re-examination of the morphology suggests that series Scabridus is better placed in section Ophiolyza and a slightly revised classification of Gladiolus in southern Africa is proposed. We also propose the replacement name G. sulculatus for the Tanzanian species, G. sulcatus Goldblatt, a later homonym of G. sulcatus Lam. Finally, a recent sighting of what appears to be G. rubellus from northern Namibia constitutes the first record of this species in the country and a major range extension from its previous known occurrence in southeastern Botswana.

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