MEDUSAS THE MAR MENOR Jellyfish are necessary it

MEDUSAS & THE MAR MENOR

‘Jellyfish are necessary, it is a mistake to fight them !’ Ignacio Franco Researcher, Instituto Español de Oceanografía (IEO) December 2014 Key information taken from a newspaper article on the physical and chemical conditions and human activities impact on the Mar Menor, by the Instituto Español de Oceanografía (IEO)

1979 - 1981 Tajo river hydraulic transfer to the Segura river basin in Murcia enabled increased agriculture in the Campos de Cartagena and elsewhere in Murcia. This has gradually intensified, along with increased tourism and development.

Original hydraulic works proposed in 1933. Civil war and later economic crises delayed the project. Manuel Lorenzo Pardo

The Mar Menor Ø Ø Most of the watercourses discharge to southern half of Mar Menor. All Campo agricultural waste discharges into the Mar Menor. Changes to the ecosystem, by waste, fertilisers and pesticides. Urban/tourism expansion changed the water – previously low nutrients content.

1950’s

Plankton, Phytoplankton and Larvae q Agricultural pesticides, insecticides, fertilizers washed into Mar Menor. q Plankton, phytoplankton and larvae thrive on this ‘pollution’. q Increased density of these microbiotic creatures.

Plankton Larvae Phytoplankton

POSSIBLE RESULT OF UNCHECKED PLANKTON INCREASE View from Outer Space of Plankton Bloom on the ocean. Bloom not easily moved in the Mar Menor (very low tidal impact)

ENTER THE EGG Cotylorhiza Tuberculata Commonly known as ‘The Fried Egg’ Jellyfish (Aguacaujada or Huevos Fritos)

Recognisable from the top as a fried egg colour, and from the bottom as shown above. Tendrils normally short and round ended.

Feeds on Plankton & Larvae. Filters the water when feeding Not an enemy. Plankton clean up the man made waste Fried Egg cleans up plankton.

v Distinctive purple globes on short tendrils. v ‘Jelly-mould’ fried egg like top. v Not normally toxic or painful. v Can be scooped up and handled. v Perhaps not the larger ones !!! Some recent years - around 5000 Tonnes netted.

2012 a MM record density of 120 MILLION

Other Mar Menor Jellyfish If it’s not a ‘Fried Egg’. . . . Give it a wide berth. . . . And leave it alone Medusa de Cuatro Ojos Moon Jellyfish Medusa Blanca / Aguamala

Each jellyfish can produce millions of descendents. Fossil records show no form change (size apart) for more than 650 million years. Are 95% water. Some species, stinging possible even if they are dead Main predator – other jellyfish (Turtles, some birds, other fish also. )

Ø No end in sight to agricultural wash into MM. Ø No end in sight to the pollution from the fields. Ø No end in sight to jellyfish population. Ø Not possible to strike a pleasing balance. Ø Fortunate water quality benefit from events.

Have a Good Summer

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