Length-length and weight-length relationships of seven deep-water fishes in the Gulf of Mexico

Regression coefficients for equations of the form Y = a + bX were estimated for total length (TL) and whole weight (W) as a function of standard length (SL) and fork length (FL) and vice versa for seven deep-water fishes. All lengths were measured in millimeters and all weights in grams. There was a significant correlation between weight and length and the types of length measurements for all species. However, the amount of variation explained by each regression varied among species. Weight-length regressions were less precise than length-length regression, as they generally are, because weights of small fish measured at sea are more inaccurate than those of large fish.Marine Scienc

Shrimp Landing Trends as Indicators of Estuarine Habitat Quality

Penaeid shrimp support three major commercial fisheries in the Gulf of Mexico. They are an estuarine-dependent species with life cycles that are completed within 1 yr. The stocks are fully exploited. Landings are independent of effort in that increased effort would not increase landings. Landings are therefore a direct measure of stock. Because the penaeids are annual species, landings are also a measure of recruitment. Since recruitment is dependent on habitat quality, landings are a measure of habitat quality and temporal trends in annual landings reveal trends in estuarine habitat quality. The landings trends indicate diminished habitat quality in Florida Bay since the mid-1980s. Landings for Louisiana and Texas reveal either increasing habitat quality or no change over the past 44 years

Movement of Spotted Seatrout Tagged in Trinity Bay, Texas

Spotted sestrout (Cynoscion nebulosus) were tagged and recaptured to determine migration patterns within the Galveston Bay system In Texas. Based on 54 recaptures of 488 tagged fish, fish tagged In northwest Trinity Bay did not frequent East or West Galveston Bay. Fish moved toward the Gulf of Mexico In late spring and summer, perhaps to feed or as part of a spawning migration, then returned to the tagging site In fall. The fitted relationship between distance traveled (Y) and Julian recapture date (X), Y ° 9.97 + 50.58 I sin [0.988 (X·90)] I, was significant (P \u3c0.01) and explained 37% of the variation In Y. The possibility of one population and a spatial separation of fish Into at least two estuarine groups can not be eliminated

An Economic Analysis of Texas Shrimp Season Closures

Management of the Texas penaeid shrimp fishery is aimed at increasing revenue from brown shrimp, Penaeus aztecus, landings and decreasing the level of discards. Since 1960 Texas has closed its territorial sea for 45-60 days during peak migration of brown shrimp to the Gulf of Mexico. In 1981 the closure was extended to 200 miles to include the U.S. Exclusive Economic Zone. Simulation modeling is used in this paper to estimate the changes in landings, revenue, costs, and economic rent attributable to the Texas closure. Four additional analyses were conducted to estimate the effects of closing the Gulf 1- to 4-fathom zone for 45 and 60 days, with and without effort redirected to inshore waters. Distributional impacts are analyzed in terms of costs, revenues, and rents, by vessel class, shrimp species, vessel owner, and crew

Winter Mass Mortality of Animals in Texas Bays

The Texas coast experienced three unusually cold weather periods in the 1980\u27s, one in 1983 and two in 1989, that caused massive fish kills. Identification of organisms killed and estimation of the number of estuarine fishes and invertebrates killed was accomplished through a systematic standardized approach utilizing airplanes, ground qualitative observations and quantitative counts, and trawling. Of 159 species identified, 103 were fishes, 45 were invertebrates, and 11 were vertebrates other than fishes. About 14 million fishes were killed in December 1983, 11 million in February 1989 and 6 million in December 1989; number of invertebrates killed ranged from 13,000 in February 1989 to 1,000,000 in 1983. These assessments are the largest in area and most comprehensive to be documented in the literature with known levels of precision. Methodology used provides reasonably precise estimates which managers can use to assess extensive widespread kills and subsequent impacts on affected populations. It is recommended that managers consider reducing fishing mortality on the remaining economically important populations after extensive kills to speed recovery of those populations