Decadal population dynamics of an intertidal bivalve (Austrovenus stutchburyi) bed: pre- and post- a mass mortality event

Mass mortality events (MMEs) on fish tend to increase recently both for cultured and wild fish both in coastal and inland waters. The MMEs on wild fish are mostly unknown. Mass mortality events on wild fishes of Mimika estuary, Papua have been recorded since long time ago and limited information was provided due to its remote area. A rapid appraisal study of mass mortality event (MME) of wild fishes chronology and cause was conducted in Yamaima river to Tifuka Estuary, Papua Province a week after the MME in April 2016. Seven sampling sites were selected. Two activities were conducted during the field survey: interview with the local people to get information on the chronology of the MME and collecting primary data on aquatic environment quality and fish samples. The occurance of goldstripe sardine inYamaima river and Tifuka estuary were triggered by the present of strong El Nino with ONI value more than 0.5oC in the ocean and atmosphere above Equator Pasific. Water quality at MME site was similar with remaining schooling fish and Tifuka estuary sites. Concentration of heavy metals in the sediment tend to decreased along with the distance from the MME site. Mass mortality of goldstripe sardinella could relate to oxygen suffocation as a result of disorentation movement of the fish shoals inaccordance with low tide and new moon phase. The number of the death goldstripe sardinella was estimated 200,000 fish with the weight of 18 tons. To mitigate MMEs in the future, efforts should be done such as: routine early detection of El Nino pattern and its effect on salinity and water temperature raising by placing key water quality parameter buoy in the mouth river of Papua and to set net or stack of logs in the cape area of west tailing levee Yamaima river to prevent the entrapment of migrating small pelagic fish specialy in the closed water area.

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Investigating a whale mass mortality event

Veterinary Record ◽

10.1136/vr.k3558 ◽

2018 ◽

Vol 183 (7) ◽

pp. 208-209

Keyword(s):

North Sea ◽

Mass Mortality ◽

Sperm Whales ◽

Southern North Sea ◽

Mortality Event ◽

Mass Mortality Event

In 2016, 30 sperm whales died having stranded in the southern North Sea. Researchers have now investigated what caused this. Georgina Mills reports

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The Pathology of Cetacean Morbillivirus Infection and Comorbidities in Guiana Dolphins During an Unusual Mortality Event (Brazil, 2017–2018)

Veterinary Pathology ◽

10.1177/0300985820954550 ◽

2020 ◽

Vol 57 (6) ◽

pp. 845-857 ◽

Cited By ~ 2

Author(s):

Kátia R. Groch ◽

Josué Díaz-Delgado ◽

Elitieri B. Santos-Neto ◽

Joana M. P. Ikeda ◽

Rafael R. Carvalho ◽

...

Keyword(s):

Viral Antigen ◽

Mass Mortality ◽

Bacterial Disease ◽

South American ◽

Mortality Event ◽

Eubalaena Australis ◽

Mass Mortality Event ◽

Southern Right Whales ◽

Lymphoid Depletion ◽

Cetacean Morbillivirus

Cetacean morbillivirus (CeMV; Paramyxoviridae) is the most significant pathogen of cetaceans worldwide. The novel “multi-host” Guiana dolphin ( Sotalia guianensis; GD)-CeMV strain is reported in South American waters and infects Guiana dolphins and southern right whales ( Eubalaena australis). This study aimed to describe the pathologic findings, GD-CeMV viral antigen distribution and detection by RT-PCR (reverse transcriptase polymerase chain reaction), and infectious comorbidities in 29 Guiana dolphins that succumbed during an unusual mass-mortality event in Rio de Janeiro state, Brazil, between November 2017 and March 2018. The main gross findings were lack of ingesta, pulmonary edema, ascites, icterus, hepatic lipidosis, multicentric lymphadenomegaly, as well as pneumonia, polyserositis, and multiorgan vasculitis caused by Halocercus brasiliensis. Microscopically, the primary lesions were bronchointerstitial pneumonia and multicentric lymphoid depletion. The severity and extent of the lesions paralleled the distribution and intensity of morbilliviral antigen. For the first time in cetaceans, morbilliviral antigen was detected in salivary gland, optic nerve, heart, diaphragm, parietal and visceral epithelium of glomeruli, vulva, and thyroid gland. Viral antigen within circulating leukocytes suggested this as a mechanism of dissemination within the host. Comorbidities included disseminated toxoplasmosis, mycosis, ciliated protozoosis, and bacterial disease including brucellosis. These results provide strong evidence for GD-CeMV as the main cause of this unusual mass-mortality event.

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