Yanasivan Kisten

• Doctor of Philosophy
• PostDoc Position at Nelson Mandela University

The tidal occurrence of larval fishes was investigated in the permanently open Kowie Estuary on the warm-temperate coast of South Africa. Larval fishes were sampled in the mouth region using two drifting light traps deployed on the ebb and flood tides every second night for two consecutive 14-day periods, coinciding with the dark moon phase. A tota...

The temporarily open-closed (TOCE) Seekoei Estuary, on the warm temperate coast of South Africa, has been subject to various anthropogenic modifications such as impoundments, water abstraction, causeway construction, and artificial breaches that have impacted its estuarine functioning. To determine the impact of these combined factors on the fish c...

Early life stages of fish were monitored in a breach channel during an opening event of the temporarily open/ closed East Kleinemonde Estuary. For comparison, early life stages were also collected in the surf zone and estuary mouth region before, during and after the breaching event on a weekly basis. The breach channel was sampled day and night at...

There is considerable uncertainty about fish population connectivity and the trajectory for larval transport following adult spawning migrations from temperate to subtropical oceanic waters off the south and east coast of South Africa. In particular, the role of the Agulhas Current and local wind drift has not been fully elucidated as drivers for c...

Cape anchovy Engraulis encrasicolus is an ecologically and economically important pelagic fish species occurring along the coast of South Africa. A recent eastward shift in Cape anchovy distribution indicates that environmental conditions are becoming more favorable for the species on the east coast. This shift is particularly important in the shel...

Refuge and feeding areas for young fish in estuaries are important for the survival of fish and replenishment of coastal fish stocks, particularly in the temperate south east coast of southern Africa. Larvae and juveniles of important fishery species recruit from the ocean into estuaries, but research has shown that estuaries are one component of b...

Information regarding the use of habitats in estuaries is often geared toward the juvenile stages and rarely toward the earlier larval stages. In some cases, postflexion larvae and early juveniles may be constituted as hyperbenthos over these habitats and their contributions are rarely considered. The fine scale habitat use of larval fishes was ass...

Estuaries are subject to high environmental variability coupled to tidal salinity shifts. Under restricted freshwater flow and prolonged drought conditions, salinity may exceed natural ranges and thus organisms may experience stressful hypersaline conditions. This study assessed the physiology of a juvenile marine estuarine-dependent species Rhabdo...

Estuarine organisms are exposed to hypersaline conditions for prolonged periods during drought conditions and under severely restricted river flow resulting from freshwater abstraction and impoundments. Consequently, marine estuarine-dependent fish such as Rhabdosargus holubi may be subjected to extreme conditions, such as hypersalinity prevailing...

Climate Change and Ocean Governance - edited by Paul G. Harris February 2019

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 th...

Recruitment of early life stages into estuaries is an integral part of the life cycle of many marine fish species. Although estuaries are naturally environmentally dynamic, they also are subject to anthropogenic disturbances, including land use and climate change, which may affect recruitment. Rhabdosargus holubi is an endemic marine-spawning speci...