Case Studies - Coastal Lagoons: Ecosystem Processes and Modeling for Sustainable Use and Development - page 405

800000

Mugil spp.

700000

R 2 = 0.72

600000 Opening of Marchamalo

artificial channel

500000

Enlargement of EI Estacio
artificial channel

400000

300000 Changes in

trophic status

200000

100000

0

140000 Sparus auratus

R 2 = 0.35

120000

100000

80000

60000

40000

20000

0

FIGURE 9.3.12 Evolution of catches of Mugil spp. and Sparus auratus in the Mar Menor
lagoon. Fisheries are artisanal and the fishing effort can be considered relatively constant over
time.

Physical, chemical, and biological data recorded for many different Mar Menor
programs over the years show some deviation from the rather classical pattern of
the eutrophication process. As mentioned above, intensive urban development for
tourism purposes started in the early 1970s, especially on La Manga. By that time,
the El Estacio Channel had opened and the largest yachting harbor in the lagoon
had been built. Simultaneously, summer residential areas were also built on the
lagoon's western coastline. Wastewater treatment plants were installed in the
main villages by the mid-1980s, but sewage overflow in many residential areas
was, and still continues to be, filtered into the lagoon after primary treatment.
Urban sewage is usually the main source of phosphorus in many Mediterranean