Fish haemoglobins: the order Clupeiformes

The haemoglobin systems of the order Clupeiformes have been studied by several researchers in 41 species belonging to three out of its five families. Most of them were investigated in the native form using electrophoretic methods, and a few were also examined from the functional point of view. Both approaches corroborate the widespread view that acidic and basic haemoglobin components, which are structurally and functionally distinct, may be present in teleost fish. However, the former are always present, whereas the latter are often lacking, depending on the taxonomic group. Both kinds of components are found in families Clupeidae and Pristigasteridae, but only acidic ones in Engraulidae. Most electrophoretic patterns show high multiplicity, and chiefly concern the acidic components. Ontogenetic variation was described in three species. Individual variants were also observed in other species, although some of these might be due to ontogenetic variations rather than genetic polymorphism.[PUBLICATION ABSTRACT]