Abstract

The lane snapper, Lutjanus synagris (Linnaeus), 1758 is the most important commercial species taken by the large and growing seine and trammel net fishery on the south shelf of Jamaica. Samples from the commercial net fishery between February, 1996 and June, 1999 showed a size range from 150 - 430 mm FL (fork length) with a mean of 232.1 mm FL (± 52.4, N = 1,094), both sexes combined. Most fishes in samples were already gutted by beachside vendors. Mean sizes for males and females were 219.5 (±72, N = 99) and 220.0 mm FL (±9.82, N = 235), respectively. Weight range for both sexes combined were 75 - 1,100g. Mean size at maturity was 268 mm FL (±0.27) and 221 (±1.85) in males and females respectively. Sex ratio (F:M) was 2.6:1.0 in the size range 150 - 310 mm FL, and above that 100% female. Prolonged spawning was found with a maximum in July for both sexes. Sagittal otoliths were examined whole and by thin (300 micrometres) section and revealed opaque and hyaline bands. Whole otolith ages produced a maximum of six years but sections showed maximum ages of at least 12 years and that whole otolith analysis alone could seriously underestimate age. Marginal increment analysis showed one opaque zone was laid down in July and one hyaline in March annually. The relationship between otolith weight and fork length was described by the regression equation y = O.0403X - 1.543 (r2 = 0.9407) for males, and for females Y = 0.0405X - 1.1716 (r2 = 0.9711). ELEFAN routines produced K = 0.25, L8 = 320 mm FL and to = -0.0001, for males and for females K = 0.070, L8 = 538.7 mm FL, to = -3.795, phi prime = 4.346.

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