[Water transfer in relation to the salinity of the medium in two isopods Cymothoidae: Meinertia oestroides (Risso, 1862) and Anilocra physodes (L., 1758) (parasites of marine fishes)].

Meinertia oestroides and Anilocra physodes (Isopoda Cymothoidae) respectively buccal and skin parasites of the teleostean Fish Boops boops are isosmotic with the surrounding medium in sea water (SW), hyperosmotic and hyperionic in diluted media. The drinking rate of meinertia is 0.73 microliter in SW and 5.30 microliter h-1 g-1 wet weight in 5/10 SW; Anilocra shows 0.31 microliter in SW and 0.21 microliter h-1 g-1 wet weight in 6/10 SW. The distribution space of [51Cr] EDTA in Meinertia reaches 32.7% in SW and 28.9% of wet weight in 5/10 SW; Anilocra indicates 29.6% in full SW and 19.2% of wet weight in 6/10 SW. The rate of primary urine production in Meineria evaluated from the biological period of [51Cr] EDTA is 130 mg in SW and 338 mg 24 h-1 g-1 wet weight in 6/10 SW. The area of pleopoda is 826 mm2 for Anilocra, 336 mm2 for Meinertia and 277 mm2/g wet weight for Emetha audouini (another buccal parasite); 92.6% for Anilocra, 84.1% for Meinertia and 81.8% for Emetha of the apparent water diffusion outflux take place through the pleopoda. The apparent permeability diffusion coefficient Pd in SW is 1.63 x 10(-4) cm/sec for Anilocra, 2.80 x 10(-4) cm/sec for Meinertia and 3.31 x 10(-4) cm/sec for Emetha. In dilute media Pd is 1.30 x 10(-4) cm/sec for Anilocra and 3.44 x 10(-4) cm/sec in Meinertia. The results are compared with those already obtained for other non parasitic Crustaceans and according to the parasitic localization of the species above mentionned. An hypothesis concerning the mechanisms of feeding (hameatophgia) is proposed. The accuracy of results is discussed.