One of the most popular management tools for Caribbean reef fisheries is a minimum mesh size for traps. It is believed that increasing the mesh size of traps in overexploited fisheries will result in higher catch rates in the long term, but lower catch rates in the short term. This study represents the first attempt to document the short-term and long-term effects of partly replacing small mesh with a larger mesh size in an artisanal coral reef fishery. A community level mesh exchange program was initiated in the Discovery Bay trap fishery in March 1991, whereby active fishers were given large mesh (1.5 inch: 3.8 cm) wire to construct traps in exchange for handing in their small mesh (1 inch: 2.5 cm and 1.25 inch: 3.2 cm) traps. Although the total number of active traps and the total number of hauls per month did not significantly change in the fishery, the proportion of small mesh traps decreased substantially as a result of the mesh exchange program, leading to a concurrent reduction of fishing mortality in smaller sized fish. Changes in the fish populations were examined by comparing catch-per-unit-effort (CPUE as number of fish per trap per haul, and kg per trap per haul); mean size of individual fish; catch composition; and length frequency distributions for the 2 most common species, for both 1.25 inch and 1.5 inch traps in 3 separate 6 mo periods (July to December) in 1990 (10 mo before the implementation of the mesh exchange program), 1991 (immediately after the implementation of the mesh exchange program) and 1994 (3 yr after the implementation of the mesh exchange program). The results indicate that reef fish populations at Discovery Bay, and hence yields to the fishery, have increased in the 3 yr since the mesh exchange program was implemented. The number of fish caught per trap haul has increased; the total weight of the catch per trap haul, at least of the smaller mesh sizes, has increased; the catch composition has shlfted towards larger and more valuable species; the mean size of fish taken by the fishery is larger; and the population of 1 narrow-bodied species investigated has shifted towards larger size classes since the increase in mean mesh size in the fishery. However, despite an increase in the gross catch per week by the trap fishery, catch rates still differ markedly between small and large mesh traps, with small mesh traps catching less per haul but more per week than large mesh traps. As a consequence, fishers still using small mesh traps are benefitting the most from recovery of the reef fish populations, which demonstrates the need for further efforts to eliminate the smaller mesh traps from the fishery.

ABSTRACT-We investigated the distribution and relative abundance of adult flyingfish by transect visual survey across a 67 500 square nautical mile (rum2) area of the eastern Caribbean from April 10 to May 6, 1988, using a 26 m research vessel and a rotating team of 23 observers. Flymgfish abundance (no. of fish per 0.5 nmi) was significantly correlated between data sets from port and starboard viewing stations, and we detected no evidence of observer bias. Flyingfish abundance varied significantly across the survey area, but was not correlated with any of the surface water characteristics measured (temperature, salinity, NOz-NO3-N, PO4-P, silicate). For the commercially harvested species Hirundichthys affinis, as well as for the smaller Parexocoetus brachypterus, abundance was high west (leeward) of the Lesser Antilles island chain and in an area between and to the east of Barbados and Tobago, and it was low between the Lesser Antilles chain and Barbados and Tobago. Cypselurus cyanopterus was less common than H affinis and P. brachypterus, and was largely restricted to the northeast of the survey area. Flyingfish distribution was patchy in all geographical zones of the survey area, mean patch width being 3.9 n m and mean inter-patch distance 2.0 nmi. Patch width and patch density (fish density m patch) were positively correlated with each other and with flyingfish abundance on a transect, and inter-patch distance was negatively correlated with fish abundance. Both within and outside of patches, flyingfish occurred in schools Flyingfish fleets from eastern Caribbean islands presently fish across areas of both high and low H. affinis abundance. Moreover, H. affinis abundance did not appear to decrease towards the east or west boundaries of the survey area, suggesting that catch rates may be similar to current rates if fishing fleets expanded their present geographical range. The high abundance indices obtained for P brachypterus indicate that the feasibility of developing a small-scale fishery for this species in the eastern Caribbean should be further explored

Abstract.A study of otolith aging and growth-rate variation in the flyingfish Hirundichthys affinis (Giinther) was conducted in the eastern Caribbean (10 -16 ~ 58-62 ~ in 1987Caribbean (10 -16 ~ 58-62 ~ in -1989. Daily otolith-increment formation was validated in laboratory-reared larvae, confirming the usefulness of otolith-increment counts for age determination of H. affinis juveniles (<150mm fork length, FL). A mark-recapture programme to validate increment formation in wild adults was unsuccessful due to tetracycline-linked mortality and insufficient tetracycline uptake in slow-growing adult otoliths. A von Bertalanffy growth curve fitted to juvenile size-at-age data gave preliminary growth-curve parameters of t o = 2.85 d and k = 0.00854 on a daily basis, with an asymptotic length, L~o , of 245 mm FL, for eastern Caribbean flyingfish.Juvenile growth rate in H. affinis is sensitive to spatial and temporal variation in temperature. Growth rates were higher where sea-surface temperatures were higher, and were higher for juveniles hatched in warmer months (April-July) than in colder months (NovemberMarch). Growth rates were also higher near islands than at more oceanic locations. Variation in juvenile growth rates may influence the spatial and temporal variation in spawning frequency observed in H. affinis.

Radiochemical assays of fish otoliths using the radioisotope pair Pb-210/Ra-226 have proven successful in determining the longevity of several long-lived fish species, but are unsuitable for determining ages less than about 3 yr. We tested the utility of the radioisotope pair Th-228/Ra-228 for determining the longevity of the four-winged flyingfish Hirundjchthys affinis of the eastern Caribbean. A new decay equation was developed for interpreting radioactivity in whole otoliths characterized by a nonlinear growth history. Assay results on both whole otoliths and otolith cores indicated that the mean age of adult flyingfish was about 1 yr, and significantly less than 2 yr. The Th-228/Ra-228 radiochemical dating technique appears to be well suited for age determinations of fish up to age 5.

We investigated the distribution and relative abundance of flyingfish spawning substrata (flotsam), eggs and larvae by neuston tows at 40 stations across a 67 500 square nautical mile (mm2) area of the eastern Caribbean from April 10 to May 6, 1988. Flotsam occurred m only 48% of the tows and in quantities < 1 g n m i l tow. Non-buoyant flyingfish eggs characteristic of Huundichthys affmis, Parexocoetus brachypterus and Cypselurus cyanopterus were virtually absent. Although 21 % of the 3014 fish eggs collected were flyingfish eggs, all but 3 of these were pelagic eggs characteristic of Exocoetus spp. The rarity of eggs and flotsam suggests that flyingfish may typically spawn on floating material until it submerges, and/or spawn on submerged substrata. Catch rates of all fish larvae and of flyingfish larvae were significantly higher in day tows than night tows, and mean larval size was larger by night. This indicates that larvae, and particularly smaller larvae, may move downwards at night. This may be a light response, since P. brachypterus larvae were more abundant at the surface around full moon than new moon. Larval abundance varied significantly across the survey area for all flyingfish, and separately for E. voLitans, P. brachypterus and C. cyanopterus. Small larvae of E. volitans were more abundant at oceanic than coastal stations. The reverse was true for P. brachypterus, indicating different spawning locations for these species. The geographical distribution of larvae of C. cyanopterus coincided with the adult distribution, both larvae and adults being rare in the southwest sector of the survey area near the South American mainland. Larvae of H. affims were relatively rare. This rarity, and the virtual absence of eggs, is surprising given the abundance of this species in the eastern Caribbean and the fact that H. affms was known to be spawning during the time of the survey. The depth at which H. affms typically spawns and hatches requires further investigation.