Evaluating the effects of catch-and-release angling on Cape stumpnose Rhabdosargus holubi in a South African estuary

Fisheries managers are increasingly promoting catch and release (C&R) as a means to manage recreational fish stocks. Several commonly used output regulations, including bag and size limits, require the mandatory release of captured fishes by anglers. In addition to mandatory C&R, conservation-conscious anglers have adopted voluntary C&R behaviour as a result of the noticeable declines in the populations of many fishery species and this behaviour is becoming increasingly popular among recreational anglers (Cooke et al. 2013a). The combination of mandatory and voluntary C&R behaviour is substantial, as Raby et al. (2014) estimated that 60% of fish captured in global recreational fisheries are released. In South Africa, Cowley et al. (2013) found that a large proportion (mean 74% [SD 7.3]) of the five most-dominant fishery species captured in the Sundays Estuary recreational fishery were released

A Preliminary study about the effect of benzo[a]pyrene (BAP) injection on the thermal behavior and plasmatic parameters of nile tilapia (Oreochromis niloticus L.) Acclimated to different temperatures

Benzo[a]pyrene is a polycyclic aromatic hydrocarbon produced by naturally and anthropogenic sources and may be present in aquatic environments. Nile tilapias were acclimated to different temperatures (20, 25 and 30 �C), one group was injected with BaP (10 ?g BaP g�fish -1) and the other with the vehicle (DMSO) without contaminant. Thereafter, the thermal behavior and plasmatic parameters (cortisol, glucose and aspartate aminotransferase) of both groups were monitored. The thermal behavior of the tilapia was negatively affected by the injection of BaP. The critical thermal maximum (CTMax) of non-contaminated fishes were 40.1, 42.3 and 43.7 �C for those acclimated to 20, 25 and 30 �C respectively, whereas in BaP group the CTMax decreased (40.7, 41.3 and 42.6 �C). Plasmatic cortisol decreased in fish injected with BaP compared to those non-contaminated, also, the decrease was greater at higher temperatures. Glucose and aspartate aminotransferase increased as function of temperature, but the increases were higher in fish injected with BaP. The results suggest that BaP affects the thermal behavior, resistance and physiological status of Nile tilapia, but the effect increase as a function of temperature

A Preliminary study about the effect of benzo[a]pyrene (BAP) injection on the thermal behavior and plasmatic parameters of nile tilapia (Oreochromis niloticus L.) Acclimated to different temperatures

Benzo[a]pyrene is a polycyclic aromatic hydrocarbon produced by naturally and anthropogenic sources and may be present in aquatic environments. Nile tilapias were acclimated to different temperatures (20, 25 and 30 °C), one group was injected with BaP (10 μg BaP g·fish -1) and the other with the vehicle (DMSO) without contaminant. Thereafter, the thermal behavior and plasmatic parameters (cortisol, glucose and aspartate aminotransferase) of both groups were monitored. The thermal behavior of the tilapia was negatively affected by the injection of BaP. The critical thermal maximum (CTMax) of non-contaminated fishes were 40.1, 42.3 and 43.7 °C for those acclimated to 20, 25 and 30 °C respectively, whereas in BaP group the CTMax decreased (40.7, 41.3 and 42.6 °C). Plasmatic cortisol decreased in fish injected with BaP compared to those non-contaminated, also, the decrease was greater at higher temperatures. Glucose and aspartate aminotransferase increased as function of temperature, but the increases were higher in fish injected with BaP. The results suggest that BaP affects the thermal behavior, resistance and physiological status of Nile tilapia, but the effect increase as a function of temperature