Conclusion :

With 588 species, the Mediterranean Sea (with the Black Sea) comprises 21.8 % of 2693 identified in all seas.

With the exception of species regarded as "endemic" to the Mediterranean (58) and the monstrillids (22), a review of common species to this sea and the surrounding seas shows that 327 species have been observed in the Atlantic and Indian (12.1 %) including 225 Calanoida and 102 of other orders. 76 species are common only with the North Atlantic (49 Calanoida and 27 podopleans) and 83 only with the Indian-Red Sea (49 Calanoida and 34 podopleans).

Such results reveals a double influence of the origin of the fauna of Mediterranean copepods: Indian (old and lessepsian) and subtropical and temperate Atlantic. But as already mentioned by various authors Mediterranean fauna has been able to recover after the messinian episode from the influx of Atlantic water (409 species of the North Atlantic are known in the Mediterranean, or 69.6 %, of whom 280 Calanoida and 129 of other orders). The siculo-Tunisian threshold appears to be a barrier, despite the penetration the surface current initiated by the Atlantic flow to the east basin.

A review of species in the west and east bassins and in the Adriatic allow to establish the following summary:

	Calanoida	Other orders (podopleans)	Total species
West basin:	309	166	475
Adriatic:	184	113	297
East basin:	254	151	405

This table shows the relative poverty or lesser diversity of the east basin, subjected to less diverse hydrological conditions than the west basin, which moreover has the influence of the intermediate current from the eastern part. Numbers to relativize because of a prospection older and more followed in the west basin than in the east basin.

The number of common species to the W and E basins is 324 (55.1 %) of which 198 Calanoida and 126 podopleans. On this total 123 species are only in the W basin (of which 92 Calanoida and 31 of other orders) and 66 only in the E basin (of which 46 Calanoida and 20 of other orders)