Migration in the sea
Migration in freshwater |
Migration between fresh- and saltwater
| |
The better-known migrations of economically important species exhibit a migration circuit for most marine species (cf. Baker 1978). This involves a spawning area, nursery area, feeding area(s), and possibly summer, winter and assembly areas. Some of these migrations involve movements to different depth zones (FAO 1979). For the purposes of CMS, it is certainly difficult to analyse which international boundaries are crossed during these complex migrations. This happens when animals
approach continental coasts or islands. In this context it is necessary to clarify whether the "range" of CMS legislation extends to a nation’s 200 miles zone. In addition, "range states [...] include states, flag vessels of which are engaged outside national jurisdictional limits in taking that migratory species" (CMS Agreement Article I,1h). This means that oceanodromous species protected by CMS could fall into the responsibility of various CMS member states, according to their respective range of fisheries.
Tab. 4.10: Threatened oceanodromous fish |
Tab. 4.10: Bedrohte oceanodrome Fische |
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Group: Order |
Family |
Scientific name |
Common name |
Red List |
CMS |
|
Actinopterygii |
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Gadiformes |
Gadidae |
Melanogrammus aeglefinus |
Haddock |
VU |
NL |
|
Gadus morhua |
Atlantic cod |
VU |
NL |
|||
Perciformes |
Scombridae |
Scomberomorus concolor |
Gulf sierra |
EN |
NL |
|
Thunnus alalunga |
Aáhi taria |
CR |
NL |
|||
Thunnus maccoyii |
Bluefin |
CR |
NL |
|||
Thunnus thynnus thynnus |
Bluefin tunny |
CR |
NL |
|||
Thunnus obesus |
Big-eye tuna |
EN |
NL |
|||
Xiphiidae |
Xiphias gladius |
Broad-bill |
EN |
NL |
||
Pleuronectiformes |
Pleuronectidae |
Hippoglossus |
Atlantic halibut |
EN |
NL |
|
Elasmobranchii |
||||||
Carchariniformes |
Carcharhinidae |
Carcharhinus |
Black whaler |
VU |
NL |
|
Carcharhinus brevipinna |
Long-nose |
VU |
NL |
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Lamniformes |
Cetorhinidae |
Cetorhinus |
Basking shark |
EN |
NL |
|
Lamnidae |
Carcharodon |
Great white shark |
VU |
NL |
||
Odontaspididae |
Carcharias taurus |
Grey nurse shark |
VU |
NL |
||
Orectolobiformes |
Rhincodontidae |
Rhincodon typus |
Whale shark |
VU |
App. II |
|
Pristiformes |
Pristidae |
Pristis pristis |
Common sawfish |
EN |
NL |
|
Rajiformes |
Myliobatidae |
Mobula mobular |
Devil fish |
VU |
NL |
|
Squatiniformes |
Squatinidae |
Squatina squatina |
Angelfish |
VU |
NL |
The case is even more difficult for lesser-known and rare pelagic species, such as rays and sharks. But efficient conservation measures could be initiated even without an exact knowledge of migratory pathways. A better management of over-exploited stocks and an efficient control of bycatch would help whole species assemblies of oceanodromous fish, in addition to many other marine organisms. An example for such interaction is the tuna-dolphin case, where the introduction of dolphin-safe legislation in the U.S. helped to lower the number of dolphin deaths from 252,000 in 1973 to 8,258 in 1984 (Körber 1998).
This document is part of the publication "Riede, K. (2001): The Global Register of Migratory Species Database, GIS Maps and Threat Analysis. Münster (Landwirtschaftsverlag), 400 pp."
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