River flow, zooplankton and dominant zooplanktivorous fish dynamics in a warm-temperate South African estuary

2018 ◽  
Vol 92 (6) ◽  
pp. 1747-1767 ◽  
Author(s):  
N. Mbandzi ◽  
R. J. Wasserman ◽  
S. H. P. Deyzel ◽  
N. G. Vine ◽  
A. K. Whitfield
Keyword(s):  
South African ◽  
River Flow ◽  
Zooplanktivorous Fish ◽  
Warm Temperate

Cyclacanthia n.g. (Demospongiae: Poecilosclerida: Latrunculiidae incertea sedis), a new genus of marine sponges from South African waters, and description of two new species

Zootaxa ◽  
2004 ◽  
Vol 725 (1) ◽  
pp. 1 ◽  
Author(s):  
TOUFIEK SAMAAI ◽  
VASHA GOVENDER ◽  
MICHELLE KELLY
Keyword(s):  
South African ◽  
Type Species ◽  
New Genus ◽  
East Coast ◽  
Hot Spot ◽  
Marine Sponges ◽  
The Family ◽  
Two New Species ◽  
Shallow Subtidal ◽  
Warm Temperate

The new genus Cyclacanthia n.g. is erected in the poecilosclerid Family Latrunculiidae for the type species Latrunculia bellae Samaai & Kelly, 2003, and two further species, Cyclacanthia cloverlyae sp. nov., and Cyclacanthia mzimayiensis sp. nov.. The latter species are from the subtropical east coast of South Africa, whereas C. bellae has only been found further south in warm temperate Algoa Bay. Cyclacanthia n.g. differs from other Latrunculiidae genera in the ontogeny, morphology and structure of the mature microsclere, the isospinodiscorhabd, which has only three major whorls of projections as opposed to the four in species of Latrunculia du Bocage. Additional diagnostic characters include the presence of broad swathes of megascleres that diverge from the base of the sponge towards the upper choanosome, where they form loose brushes and the typical whispy reticulation of most Latrunculiidae. The ectosome is composed of a dense tangential layer of megascleres, an irregular palisade of microscleres at the surface, and a permanently encrusting habit. Cyclacanthia n.g. is the second new latrunculid genus recently described from shallow subtidal South African waters, following major revision of the family. The presence of species in four of the five known genera in the family, on South African coastlines, suggests a diversity hot-spot for the family in this region.

scholarly journals Modelling the occurrence of postflexion stages of a marine estuarine-dependent fish in temperate South African estuaries

2017 ◽  
Vol 81 (1) ◽  
pp. 27 ◽  
Author(s):  
Yanasivan Kisten ◽  
Nadine A. Strydom ◽  
Renzo Perissinotto ◽  
Sourav Paul
Keyword(s):  
South African ◽  
Environmental Variability ◽  
Water Clarity ◽  
Light Extinction ◽  
Light Extinction Coefficient ◽  
In Situ Conditions ◽  
Seasonal Basis ◽  
Biogeographic Regions ◽  
Lake Systems ◽  
Warm Temperate

The movement of postflexion larvae of marine estuarine-dependent species into estuaries is critical for the survival of fishes reliant on estuaries as nurseries. However, detailed studies focused on environmental variability experienced by postflexion larvae entering a range of estuary types under varying conditions are rare. This study assessed the in situ conditions (temperature, salinity and water clarity) under which the southern African endemic fish Rhabdosargus holubi (Sparidae) recruits into estuaries. Postflexion larvae were sampled in three biogeographic regions (cool temperate, warm temperate and subtropical boundary), which included three estuary types (permanently open estuaries (POEs), temporarily open/closed estuaries and estuarine lake systems) on a seasonal basis, independent of each other. Rhabdosargus holubi larvae were more abundant in spring and summer, in POEs in the warm temperate region. Models predicted that higher larval occurrence in estuaries is a function of lower salinity (e.g. mesohaline zones of 5-17.9 salinity) and lower water clarity (e.g. 0-0.2 Kd, light extinction coefficient), particularly for warm, temperate POEs. This re-emphasizes the importance of freshwater for optimal nursery functioning, which may be compromised by impoundments, abstraction and climate change in water-short countries like South Africa.

Sign in / Sign up

Export Citation Format

Share Document