Movements of flyingfish (Hirundichthys affinis) in the eastern Caribbean

A total of3,559 f1yingfish (Hirundichthys affinis) were tagged and released at three locations across the eastern Caribbean (Barbados, Dominica and Tobago) at the beginning of the 1988 fishing season (January and February) and at Tobago near the end of the season (May), to examine the extent and direction of their subsequent movements. A further 3,460 f1yingfish were tagged and released at Tobago during the 1989 fishing season, between January and May, to examine seasonal variation in movements. Overall recapture rate was 4.5%. Post· tagging survival was not affected by sex or by the method of capture at tagging. However, recapture rates varied with both place and time of release. Total recapture rates were highest for fish released at Tobago and lowest for fish released at Dominica. Total recapture rates off Tobago were highest for fish released near the beginning (January/February) and at the peak (March/April) of the fishing season, and lowest for fish released near the end of the season (May). Some fish remained in the release location for several weeks. However, there was considerable mixing of adult flyingfish among eastern Caribbean islands, with 10% of all recaptures being from territorial waters other than those in which the fish were released. This suggests that H. affinis in the eastern Caribbean is probably not segregated into islandspecific populations. Dispersion migrations were recorded in all directions, although northwesterly was most common. Dispersion rate was not affected by fish size or sex, but varied with maturity state and time of year at release. Fish at maturity Stages 2 (maturing) and 3 (mature) showed greater dispersion than fish in Stages 4 (running ripe) and 5 (spent). For f1yingfishreleased at Tobago, dispersion was greatest in the early part of the year and decreased steadily through the season. Despite the importance of flyingfish (Hirundichthys affinis) as a major fishery resource throughout most of the eastern Caribbean (Mahon et al., 1986) and the continued expansion of pelagic fishing fleets in the region, almost nothing is known about the movements of this species, and no attempt has been made to determine stock structure. It is well known that there is considerable seasonal variation in availability of adult flyingfish to commercial fishing gear, resulting in a sharply seasonal (midNovember to mid-July) fishery for flyingfish throughout the eastern Caribbean islands (Mahon et al., 1986). Various hypotheses have been proposed to explain the seasonal variation (Brown, 1942; Hall, 1955; Mahon et al., 1981; Hunte and Mahon, 1982; Storey, 1983; Mahon et al., 1986; Khokiattiwong, 1988), but these have not been tested, and the pattern of movement remains unclear. Tagging programs can be valuable in determining migration patterns and, in collaboration with other data, may allow determination of stock structure (Jones, 1977; White et a1., 1982). For an open ocean species that has a short life-span and is commercially fished by several different fisheries, as is the case for flyingfish in the eastern Caribbean, such information is difficult to obtain by tagging. However, if tag returns can be obtained, they would provide valuable information on movements and mixing of individual fish, provide insights into determining stock structure, and assist in determining appropriate management options for the resource. Previous attempts at tagging H. affinis (off Barbados: Mulloney, 1961; Lewis, 1964; off Brazil: Barroso, 1967) were successful but fairly small scale. Mulloney (1961) tagged and released 762 adult H. affinis off Barbados near the end of the