Floc and sediment properties and their environmental distribution from a marine fish farm

Open ocean pen aquacultural operations are leaky systems with potential environmental impacts of metabolic excretions products, feed additives, and anti‐fouling agents. This study analysed the water–sediment interface along a horizontal transect away from a fish farm, noting variations between water, floc, and sediment properties. The properties examined included nitrogen (N), phosphorus (P), carbon (C), sulphur (S), and trace element content, as well as heterotrophic bacteria populations. C, N, labile P, NH₄, Ca, and Zn were elevated in surface sediments at the farm in comparison with sites 100 and 300 m away. The flocs had higher levels of Mg, K, and heterotrophic bacteria than adjacent sediments, indicating the importance of the microbial communities in flocs. The flocs were important in their role as a retention and potential transport mechanism for metals, increasing in concentration of Al, Fe, and Mn with distance from the farm.     

Ischaemic and haemorrhagic stroke in the dog

Cerebrovascular disease results from any pathological process of the blood vessels supplying the brain. Stroke, characterised by its abrupt onset, is the third leading cause of death in humans. This rare condition in dogs is increasingly being recognised with the advent of advanced diagnostic imaging. Magnetic resonance imaging (MRI) is the first choice diagnostic tool for stroke, particularly using diffusion-weighted images and magnetic resonance angiography for ischaemic stroke and gradient echo sequences for haemorrhagic stroke. An underlying cause is not always identified in either humans or dogs. Underlying conditions that may be associated with canine stroke include hypothyroidism, neoplasia, sepsis, hypertension, parasites, vascular malformation and coagulopathy. Treatment is mainly supportive and recovery often occurs within a few weeks. The prognosis is usually good if no underlying disease is found.