Pathogenicity and culture studies comparing the Aphanomyces involved in epizootic ulcerative syndrome (EUS) with other similar fungi

Pathogenicity and cultural experiments described here provide futher evidence that a distinct species of Aphanomyces is responsible for much of the characteristic pathology of epizootic ulceration syndrome (EUS). Zoospores from 58 fungal isolates were injected intramuscularly in snakehead fish, Channa striata (Bloch). These fungi comprised: Aphanomyces strains isolated from EUS-affected fish; saprophytic Aphanomyces , Achlya and Saprolegnia spp. from infected waters; and further saprolegniaceous fungi involved in other diseases of aquatic animals. Only the Aphanomyces strains isolated from fish affected by EUS, Australian red spot disease (already considered synonymous with EUS) or mycotic granulomatosis described from Japan were able to grow invasively through the fish muscle and produce the distinctive EUS lesions. In contrast to Aphanomyces astaci Schikora, the EUS- Aphanomyces was shown to be unable to infect noble crayfish, Astacus astacus L. The snakehead-pathogenic strains were further distinguished from all the other fungi under comparison by their characteristic temperature-growth profile and inability to grow on certain selective fungal media.     

Using fishers' anecdotes, naturalists' observations and grey literature to reassess marine species at risk: the case of the Gulf grouper in the Gulf of California, Mexico

Designing fishing policies without knowledge of past levels of target species abundance is a dangerous omission for fisheries management. However, as fisheries monitoring started long after exploitation of many species began, this is a difficult issue to address. Here we show how the ‘shifting baseline’ syndrome can affect the stock assessment of a vulnerable species by masking real population trends and thereby put marine animals at serious risk. Current fishery data suggest that landings of the large Gulf grouper (Mycteroperca jordani, Serranidae) are increasing in the Gulf of California. However, reviews of historical evidence, naturalists’ observations and a systematic documentation of fishers’ perceptions of trends in the abundance of this species indicate that it has dramatically declined. The heyday for the Gulf grouper fishery occurred prior to the 1970s, after which abundance dropped rapidly, probably falling to a few percent of former numbers. This decline happened long before fishery statistics were formally developed. We use the case of the Gulf grouper to illustrate how other vulnerable tropical and semi‐tropical fish and shellfish species around the world may be facing the same fate as the Gulf grouper. In accordance with other recent studies, we recommend using historical tools as part of a broad data‐gathering approach to assess the conservation status of marine species that are vulnerable to over‐exploitation.     

Eight urgent,fundamental and simultaneous steps needed to restore ocean health,and the consequences for humanity and the planet of inaction or delay

1. The ocean crisis is urgent and central to human wellbeing and life on Earth; past and current activities are damaging the planet's main life support system for future generations. We are witnessing an increase in ocean heat, disturbance, acidification, bio‐invasions and nutrients, and reducing oxygen levels. Several of these act like ratchets: once detrimental or negative changes have occurred, they may lock in place and may not be reversible, especially at gross ecological and ocean process scales.
2. Each change may represent a loss to humanity of resources, ecosystem function, oxygen production and species. The longer we pursue unsuitable actions, the more we close the path to recovery and better ocean health and greater benefits for humanity in the future.
3. We stand at a critical juncture and have identified eight priority issues that need to be addressed in unison to help avert a potential ecological disaster in the global ocean. They form a purposely ambitious agenda for global governance and are aimed at informing decision‐makers at a high level. They should also be of interest to the general public.
4. Of all the themes, the highest priority is to rigorously address global warming and limit surface temperature rise to 1.5°C by 2100, as warming is the pre‐eminent factor driving change in the ocean. The other themes are establishing a robust and comprehensive High Seas Treaty, enforcing existing standards for Marine Protected Areas and expanding their coverage, especially in terms of high levels of protection, adopting a precautionary pause on deep‐sea mining, ending overfishing and destructive fishing practices, radically reducing marine pollution, putting in place a financing mechanism for ocean management and protection, and lastly, scaling up science/data gathering and facilitating data sharing.
5. By implementing all eight measures in unison, as a coordinated strategy, we can build resilience to climate change, help sustain fisheries productivity, particularly for low‐income countries dependent on fisheries, protect coasts (e.g. via soft‐engineering/habitat‐based approaches), promote mitigation (e.g. carbon storage) and enable improved adaptation to rapid global change.

     

Factors influencing recruitment patterns of Golden Perch (Macquaria ambigua oriens) within a hydrologically variable and regulated Australian tropical river system

Abstract – The links between river flows, water temperature, river regulation and recruitment variability of Golden Perch, Macquaria ambigua oriens, were investigated from the Fitzroy Basin, Queensland. The dominant age classes determined by interpreting growth marks observed in otoliths were variable among rivers. Positive correlations between the age frequency and monthly river flow volumes were greatest in summer (December–March) conversely, autumn, winter and spring river flows correlated poorly for most rivers. Water temperature exhibits strong seasonality across the basin with mean monthly temperatures >23 °C generally occurring between October and April. These data indicate the combination of water temperature and increased river flows are important factors for recruitment. The degree of river regulation is also suspected of contributing to increased variability in dominant age classes within rivers. This assessment highlights the importance of timing of river flows in mitigating the negative effects of river regulation on golden perch populations.     

Feeding and digestive problems in horses. Physiologic responses to a concentrated meal

The association of feeding practices with the development of digestive disorders in horses has long been recognized, although the underlying mechanisms had been barely considered. The physiologic consequences of meal frequency may help to explain the relationship and prove to be of major significance in the induction of many conditions. Many Equidae kept for performance and leisure activities are fed high-energy, low-forage rations twice daily, with limited access to hay or grazing. Rapid ingestion of such meals stimulates a copious outpouring of upper alimentary secretions and results in transient hypovolemia (15% plasma volume loss). Subsequent activation of the renin-angiotensin-aldosterone system (RAAS) contributes to the preservation of circulatory status. Large meals may accelerate digesta passage to the cecum and, thereby, increase soluble carbohydrate availability for large intestinal fermentation. Intense periods of fermentation develop that require significant shifts of fluid into the colonic lumen. This is followed by net fluid absorption, which, in part, is dependent on postprandial increases of aldosterone. Potential consequences of these events include (1) imbalances in the RAAS response, which may promote conditions favorable to gastrointestinal disturbance, notably large intestinal impaction, and (2) changes in the gastrointestinal microflora, which may affect the intraluminal endotoxin pool and the population of enterotoxin-producing bacteria. In contrast to episodic feedings, similar changes are absent or greatly attenuated under simulated grazing conditions (for example, small, frequent meals). Thus, modification of management practices to facilitate a more continuous feeding pattern may significantly reduce the incidence of digestive problems in the stabled horse.     

Failure to establish congenital bluetongue virus infection by infecting cows in early pregnancy.

Two groups of 10 pregnant cows were inoculated with bluetongue virus type 11 at either 40 or 60 days of gestation. All the cows became infected as judged by the detection of viraemia and seroconversion but they showed no clinical signs. Seventeen of the cows produced live calves none of which showed any evidence of prenatal infection. After challenge with the same virus all the calves became viraemic and seroconverted. The response to challenge of the two groups did not differ from that of a control group challenged at the same time. It was concluded that the infection of pregnant cows in early gestation with this virus did not result in the transplacental infection of the fetuses and did not produce immunotolerant, latently infected calves.     

Effect of interval between doses on response of the pony to sodium bicarbonate.

Three pony geldings were given sodium bicarbonate orally in order to study the effect on blood pH and bicarbonate and to determine if frequency of dosing influences the response. In a preliminary study, it appeared that a carry-over effect might occur if the interval between dosing was only 2 days. The ponies received 2 doses of sodium bicarbonate (400 mg/kg) 7 days apart in trial one and then in trial two they received 2 doses of sodium bicarbonate 4 days apart. The sodium bicarbonate was mixed with 2 liters of warm water and given through a nasogastric tube on each trial day. Blood samples were taken before dosing, and every half hour after for five and a half hours. The blood was analyzed for pH and bicarbonate. There did not seem to be a carry-over effect due to sodium bicarbonate administration since there was little difference in the responses between the first and second doses of each trial.