National Marine Week is the Wildlife Trusts’ nationwide celebration of all things marine. Despite the name, it lasts 15 fun-filled days to allow for the variation in tide times around the country.

Two common enquiries we receive relating to the sea involve seawater and jellyfish.

Seawater has a salinity of about 3.5% (mostly as sodium chloride). Most cases of seawater ingestion reported to VPIS are symptomatic and fatal hypernatraemia can occur. Initial signs of hypernatraemia are non-specific with vomiting, diarrhoea, depression, lethargy, tremor, polydipsia and dehydration. The aim of treatment is to replace water and electrolytes and to aid renal excretion of sodium.

The severity of jellyfish stings varies with the species; not all jellyfish sting. As dead jellyfish can sting even weeks after death, licking or ingestion of a jellyfish can result in a sting. In dogs, effects usually occur immediately and last a few hours. Signs reported are vomiting or retching, oedema including laryngeal oedema, hypersalivation and oral irritation, pain, pyrexia, diarrhoea or haemorrhagic diarrhoea, twitching or tremor, panting, dysphagia, stridor, choking, coughing and polydipsia. Skin irritation can occur and the dog may lick the affected area. In most cases signs are relatively mild.  Treatment varies depending on the species of jellyfish in question, mostly involving symptomatic and supportive care.