In September 1986, we collected neuston (1 x 2 m, 0.947 mm mesh) and surface chlorophyll a samples and hydrographic data at 46 stations around the discharge plume of the Mississippi River. Transects were positioned so that the 3 water masses in the plume area -plume water, Gulf of Mexico shelf water and frontal water (a mixture of the former 2) -were sampled. The plume was represented by a shallow lens of water < 3 4 '10 salinity and < 29 "C resting atop warmer (> 29 "C) and more saline (> 34 %) Gulf of Mexico shelf water. Strong turbidity fronts with a scale of 50 to 100 m form, relax and reform approximately at tidal frequencies within the frontal region that has a larger scale of 6 to 8 km. Total ichthyoplankton catch per tow, individual surface chlorophyll a values and macrozooplankton displacement volumes were all significantly greater in frontal waters than adjacent Gulf of Mexico shelf or plume waters Hydrodynamic convergence at the continually forming and relaxing turbidity fronts most likely accounts for concentrated neustonic ichthyoplankton, and at least partially for high macrozooplankton values as well, in frontal waters. Elevated macrozooplankton displacement volumes in frontal waters may also result from higher rates of proliferation of macrozooplankton biomass. High primary production in frontal water is probably due to the mixing of nutrientrich, but turbid, plume water (where photosynthesis is light limited) with clear, but nutrient-poor, Gulf of Mexico shelf water (where photosynthesis is nutrient limited) creating favorable phytoplankton growth conditions. Concentrations of ichthyoplankton and zooplankton offer rich trophic resources that some species utilize to gain superior growth. Faster growth will lead to increased survival and recruitment (because larvae pass through the period of greatest vulnerability to predation by gapelimited predators more quickly) if larval growth is increased disportionately to larval mortality from predation.

Scomberomorus caval/a, and Spanish mackerel, S. macu/atus were collected from 1975 through 1977 off the Texas coast. Both species were captured from May through October. S. caval/a was relatively more abundant of the two species and occurred most abundantly over the middle and outer continental shelf (35-183 m). At least 35% of the larvae were captured in September of each year. S. maculatus larvae occurred most abundantly over the inner continental shelf (12 to 50 m). S. caval/a spawned from May through September to early October, with the greatest spawning intensity occurring over the middle and outer continental shelf during September. S. maculatus spawned from May through September to early October over the inner continental shelf, but spawning was less intensive and more irregular than for S. caval/a. Comparisons with other larval studies of S. caval/a and S. maculatus suggest that the northwestern and northeastern Gulf of Mexico and the coast off the southeastern United Stales are important spawning areas for S. caval/a and that the eastern and northeastern Gulf of Mexico are important spawning areas for S. maculatus.

Blue runner were obtained from commercial fisheries in south Florida, northwest Florida, and the Mississippi Delta. Monthly mean gonadosomatic indices indicated that peak spawning occurred in June, July, and August for all areas with a secondary peak in October for northwest Florida. The spawning season was confirmed for the south Florida collection by histological examination of gonads. Probit analysis of 185 northwest Florida blue runner captured during peak spawning months indicated a length-at-maturity of 267 mm.

Ecological data are given for young‐of‐the‐year pompano and permit collected in the Tampa Bay, Florida, area for 1962 and 1963. Additional data are included from stocks in the Tampa Bay and St. Augustine areas of Florida in 1967 and 1968. Distribution, seasonal occurrence, abundance, spawning, growth rates, food preferences, parasites and disease are included for each species. The occurrence of these fish with respect to water temperature, salinity, oxygen, and pH is discussed.

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