LENGTH-WEIGHT RELATIONSHIP AND CONDITION OF LEIOSTOMUS XANTHURUS LACEPEDE, AND MICROPOGON UNDULATUS (LINNAEUS) IN GALVESTON BAY, TEXAS

Length-weight data on juvenile spot, Leiostomus xanthurus Lacdpede, and Atlantic croaker, Micropogon undulatus (Linnaeus), taken in Gal- veston Bay, Texas during 1963, were used to examine variations in condition of fish between nursery areas within the bay and with size of fish, time, temperature and salinity. Changes in the condition of spot were associated with habitat, size, season, and temperature and in the condition of Atlantic croaker with size, season, and salinity. Because these fish were immature, gonad development was discounted as a causative factor, and it was concluded that changes in condition represented changes in body form associated with growth and fatness that are in turn associated with suitability of the environment. The spot, Leiostomus xanthurus Lacepbde, and the Atlantic croaker, Micropogon undulatus (Linnaeus) are two of the more abundant fishes in coastal waters of the Gulf of Mexico and undoubtedly play an important role in the trophic dynamics of their habitat. Both are bottom dwellers which range from the New England Coast south to the Yucatan Peninsula and in depths of over 100 fathoms. Adults reside at sea and spawn during the winter and early spring in close access to their estuarine nursery grounds. The young move directly into the bays and lagoons, using these shallow, nutrient-rich waters during postlarval and juvenile development and return to the Gulf during late summer or fall. Considerable information relating to seasonal abundance, length frequency distribution, size at maturity and range of occurrence at varying temperatures and salinities has been collected for these species on both the Atlantic and Gulf coasts. Data on the relationship between lengths and weights and its application to the ecology of these species, however, are not extensive. Dawson provided length-weight data on spot from South Carolina (1958) and spot and croaker from the