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Despite relatively low number of species among Indian Ocean representatives of the families Istiophoridae and Xiphiidae (5 species and 1 species respectively), known as billfish, their identification for a long time was (and actually still is) a problematic issue either for scientists, scientific observers and in higher scale to fishermen and fishing industry.
Taxonomic studies of Nakamura (Nakamura, 1983, 1985) resolved most of questions of correct identification of intact fish for scientists, while later guide of SPC (Chapman et al., 2006) and WCPFC (McAuliffe et al., 2007) transferred this knowledge to fishermen and general public. In the Indian Ocean perspective FAO guides (Nakamura, 1984, 1984a) and, in particular, recent work of IOTC (IOTC, 2012) were important steps for overall improvement of situation.
In the same time there is urgent need for correct identification of billfish, that were dressed onboard of fishing vessel and not identified to species level or when verification of initial identification is necessary. There are no dedicated guides for dressed billfish while guide developed for intact fish are not always useful when identification occurs at landing or during the fish processing.
Objective of this study is to develop field guide of identification for dressed billfish (sailfish, Istiophorus platypterus; marlins Makaira indica, M. mazara; and spearfish Tetrapturus audax1, T. angustirostris) unloaded in the fishing ports of the Reunion Island. This guide aimed to help local fisheries sector (fishermen, processing factories) in identification of dressed billfish based on typical post pre- processing characteristics of every species during or after unloading from the fishing vessel.
It is recognised that recent advances in molecular analysis of billfish genetics allowed to develop extended revision of the billfish taxonomic status and hierarchy, in particular re-establishing of genus Istiompax and Kajikia (Collette et al., 2006). Earlier same approach lead to apparent synonymysation of Indo- Pacifica blue marlin Makaira mazara and Atlantic blue marlin M. nigricans, preserving the latter as a valid name (Buonaccorsi et al., 2001; Graves, McDowell, 2003). In spite of that advanced approach we are following to ‘conservative’ taxonomy of billfish based on morphological and morphometric studies developed by Nakamura (1983).
