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target="_blank" rel="nofollow" href="#ulink_1b9d5d09-ab33-5277-aadf-5cb67eb77ff1">Figure 2.8). Similarly, Harrison & Whitfield (2008) recorded that the fish assemblages in South Africa differed between estuarine types, particularly within the warm‐temperate and subtropical regions, and noted that the numerical contribution of marine species, such as MEOs, was higher in permanently open than predominantly closed estuaries. This is probably a reflection of a permanent connection with the sea, which allows unrestricted access to permanently open estuaries, a conclusion supported by the occurrence of marine stragglers within these systems. Freshwater and estuarine species were generally more abundant in temporarily open/closed estuaries than in permanently open systems, probably also reflecting the degree of isolation from the sea. Bennett (1989) recorded that, in estuaries in the cool‐temperate Western Cape Province, MEO species dominated the fish community in the permanently open Palmiet Estuary while resident estuarine species dominated that in the nearby normally closed Bot Estuary.
Table 2.1 Number of fish species from five ecological guilds (DA = diadromous, FW = freshwater, ES = estuarine, MEO = marine estuarine‐opportunist, MS = marine straggler) per selected estuarine system in each of three European regions (data from Pihl et al. 2002; Akin et al. 2005; Leitão et al. 2007).
| Region/estuary | Number of species in each guild | Total number of species | ||||
|---|---|---|---|---|---|---|
| DA | FW | ES | MEO | MS | ||
| Baltic region | ||||||
| NW Åland | 3 | 17 | 16 | 5 | 3 | 44 |
| Göta | 4 | 3 | 15 | 14 | 17 | 53 |
| Gullmarsfjord | 4 | 1 | 13 | 13 | 19 | 50 |
| Darss‐Zingster | 6 | 20 | 10 | 5 | 3 | 44 |
| Oderhaff/Stettin | 9 | 29 | 8 | 3 | 1 | 50 |
| Boreal/NW Atlantic region | ||||||
| Weser & Elbe | 9 | 33 | 12 | 16 | 8 | 78 |
| Westerschelde | 7 | 13 | 12 | 16 | 8 | 56 |
| Oosterschelde | 9 | 1 | 16 | 23 | 25 | 74 |
| Ems‐Dollard | 7 | 3 | 13 | 21 | 9 | 53 |
| Loch Etive | 4 | 1 | 14 | 9 | 22 | 50 |
| Forth | 7 | 0 | 10 | 9 | 19 | 45 |
| Humber | 9 | 18 | 15 | 16 | 27 | 85 |
| Thames | 8 | 21 | 19 | 22 | 40 | 110 |
| Mersey | 6 | 13 | 12 | 19 | 19 | 69 |
| Somme | 4 | 0 | 7 | 11 | 6 | 28 |
| Seine | 11 | 9 | 15 | 20 | 24 | 79 |
| Loire | 10 | 8 | 4 | 18 | 6 | 46 |
| Bay of Cádiz | 1 | 0 | 12 | 22 | 18 | 53 |
| Guadalquivir | 7 | 2 | 9 | 10 | 4 | 32 |
| Ria de Aviero | 7 | 4 | 15 | 16 | 13 | 55 |
| Óbidos | 4 | 0 | 9 | 21 | 11 | 45 |
| Mondego | 3 | 8 | ||||
