Steatitis in Egrets and Herons From Japan

Neagari, Yasuko; Arii, Suzue; Udagawa, Mai; Onuma, Manabu; Odaya, Yoshiya; Kawasaki, Takeshi; Tenpaku, Makio; Hayama, Hisayo; Harada, Kenichi; Mizukami, Masaya; Murata, Koichi

doi:10.7589/0090-3558-47.1.49

Cited by 19 publications

(28 citation statements)

References 11 publications

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“…Potential causes that have been explored include opportunistic piscivory following fish kills (Dabrowski et al, 2014a); bioaccumulation of Al and Fe in the food chain (Oberholster et al, 2012); and altered aquatic food-webs (Huchzermeyer et al, 2011). Outbreaks of pansteatitis in aquatic fauna concurrent to blooms of M. aeruginosa have been previously documented (Nichols et al, 1986;Neagari et al, 2011); however, no definitive link between the disease and cyanobacteria has been established. Although the simultaneous timing of the outbreaks at two isolated locations on the Olifants River may have been coincidental, it is possible the drought may have somehow been related as a common environmental factor affecting both locations.…”

Section: Introductionmentioning

confidence: 99%

Impact of temporary desiccation on the mobility of nutrients and metals from sediments of Loskop Reservoir, Olifants River

Dabrowski

Baldwin

Hill

et al. 2017

WSA

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South Africa is prone to droughts and is heavily dependent on stored water resources. Few studies in South Africa have investigated the impact of drought on water quality when rainfall resumes and reservoir sediments are rewet. Other research has shown that several negative impacts may occur with rewetting, including eutrophication, and acidification with increased metal solubility. In this study, the impact of drying and rewetting sediments on the mobility of nutrients and metals is explored using sediments from Loskop Reservoir. Rarely exposed sediments were collected from three sites, dried at 35°C for 36 days, and then rewet under aerobic conditions. Filtered water samples were collected on Days 1, 2 ,4, 7, 11 and 16 following rewetting, and analysed for , and were compared to reference (non-drought) treatments that were maintained under saturated conditions. Acute toxicity tests were performed using Daphnia magna to establish if toxic effects were associated with changes in water quality following sediment rewetting. Following rewetting, elevated SO 4 2-indicated the mobilisation of acid from sulfide oxidation, with an associated reduction in pH. Nitrification was evident as high quantities of organic N and NH 4 + were initially released, followed by increases in NO 2 -+ NO 3 -. Total P increased, but PO 4 3-reduced. This was attributed to complexes formed between PO 4 3-and Fe (FePO 4 ) and Al (AlPO 4 ). Amounts of Fe and Al released were lower following rewetting due to the formation of relatively immobile (hydr)oxides. In contrast, Mn increased substantially reaching maximum values > 2 300 mg/m 2 (14 000 µg/L). There were no acute toxic effects observed to D. magna. This study highlights the potential for acidification, mobilisation of nutrients, SO 4 2-, and Mn following rewetting of reservoir sediments under aerobic conditions. This information may be incorporated into reservoir and catchment management plans in the form of revised water quality guidelines and a better ability to predict how drought impacts water quality in our stored water resources.

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Section: Introductionmentioning

confidence: 99%

Impact of temporary desiccation on the mobility of nutrients and metals from sediments of Loskop Reservoir, Olifants River

Dabrowski

Baldwin

Hill

et al. 2017

WSA

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“…Pansteatitis is an inflammatory reaction accompanying fat cell necrosis that can cause death in a wide range of species (Roberts et al 1979, Herman and Kircheis 1985, Ladds et al 1995, Wong et al 1999, Niza et al 2003, Goodwin 2006, Roberts and Agius 2008, Neagari et al 2011.…”

Section: Introductionmentioning

confidence: 99%

Ecosystem change and the Olifants River crocodile mass mortality events

Woodborne¹,

Huchzermeyer²,

Govender³

et al. 2012

Ecosphere

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Abstract. Nile crocodile (Crocodilus niloticus) mass mortality events in the Olifants River between the Letaba River confluence in South Africa and Lake Massingir in Mozambique have been attributed to pansteatitis: a disease that affects fat depots of the animals. The disease is also found in sharptooth catfish (Clarias gariepinus) in the same area, and the cause of the disease is attributed to pollution. Although the Olifants River Valley is polluted, the impact of interventions such as dam construction on biodiversity receives little attention. We show that the onset of the pansteatitis epidemic in crocodiles and sharptooth catfish at the Olifants/Letaba confluence coincided with back-flooding of Lake Massingir that changed the Olifants River from a rock and sand substrate river to a clay substrate lake. Isotopic analysis shows that sharptooth catfish shifted from a predominantly vegetarian to a piscivorous diet that is highly correlated with pansteatitis prevalence, and crocodiles and tiger fish (Hydrocynus vittatus) show coincident trophic level increases. The evidence suggests that the ecosystem change altered the structure of the lotic foodweb and that an exotic or extralimital fish has invaded the confluence and is the vector of the pansteatitis epidemic. The invasive fish species is yet to be identified. The pansteatitis epidemic is an unintended ecological consequence of damming this river.

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“…Recently an outbreak of steatitis in wild egrets and herons was reported from a reservoir in Japan (Neagari et al 2011). However, steatitis has been reported in wild marine fish, the common dab, Limanda limanda (L.), with a suspected pollution-related aetiology (Begg, Bruno & McVicar 2000).…”

Section: Discussionmentioning

confidence: 99%

Prevalence of pansteatitis in African sharptooth catfish, <i>Clarias gariepinus</i> (Burchell), in the Kruger National Park, South Africa

Huchzermeyer

2012

J. S. Afr. Vet. Assoc.

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Pansteatitis was confirmed in sharptooth catfish, Clarias gariepinus (Burchell), from three main locations within the Kruger National Park (KNP); the Olifants River Gorge, Engelhard Dam on the Letaba River and from the Sabie River in the Sabiepoort. An increasing prevalence of pansteatitis was observed in catfish during repeated samplings from the Olifants Gorge from 2009 to 2011 and co-existence of old and recent lesions indicated on-going incitement of pansteatitis. Only a low prevalence of pansteatitis was observed in catfish sampled from the Olifants River upstream of the Gorge in the KNP and no pansteatitis was observed in catfish sampled from a rain-filled dam not connected to the Olifants River. Common to both the Olifants Gorge and the Sabiepoort is the damming of the rivers in Mozambique to form lakes Massingir and Corumana respectively. Anthropogenic activities resulting in potential pollution of the rivers differ greatly between these two catchments, providing argument against a primary pollution-related aetiology of the pansteatitis found at these two sites. Compared with other sites, analysis of stomach contents of catfish from the Olifants Gorge and the Sabiepoort strongly suggested that consumption of a predominantly fish diet was associated with the development of pansteatitis in these fish. In a farmed population of catfish used as positive control, development of pansteatitis could be ascribed to consumption of rancid fish waste from a trout slaughterhouse. In the Olifants Gorge, alien invasive silver carp, Hypophthalmychthys molitrix (Valenciennes), seasonally migrate upstream out of Lake Massingir to spawn. This schooling species is an obligate phytoplankton feeder with consequent high levels of adipose tissue n-3 polyunsaturated fatty acids. In the Olifants Gorge, at least, this may explain seasonal exposure to levels of polyunsaturated fats in the diets of catfish and crocodiles to which these animals are not adapted. The possible roles of diet, membrane lipid composition and metabolic rate of fish, sediment pollution and seasonal drop in environmental temperature in the pathogenesis of pansteatitis in the catfish are discussed. Further studies are needed to verify some of these speculations.

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Steatitis in Egrets and Herons From Japan

Cited by 19 publications

References 11 publications

Impact of temporary desiccation on the mobility of nutrients and metals from sediments of Loskop Reservoir, Olifants River

Impact of temporary desiccation on the mobility of nutrients and metals from sediments of Loskop Reservoir, Olifants River

Ecosystem change and the Olifants River crocodile mass mortality events

Prevalence of pansteatitis in African sharptooth catfish, <i>Clarias gariepinus</i> (Burchell), in the Kruger National Park, South Africa

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