The Oyster Industry of Eastern Mexico

Mexico has an oyster industry of substantial size, ranking about sixth in the world. In 1993, among the top ten oyster producers, Korea, Japan, the United States, China, and France ranked ahead of Mexico, while the Philippines, Australia, Canada, and New Zealand trailed it (Fig. 1). On its east coast, the species landed is the eastern oyster, Crassostrea virginica, while on its west coast C. corteziensis, C. iridescens, and the Pacific oyster, C. gigas, are landed. During the last 10-15 years, annual production often was at least 50,000 t of shelled oysters, or nearly 1.5 million bushels (Anonymous, 1995), with the great preponderance (90%) coming from a series of lagoons connecting with the Gulf of Mexico along the east coast (Fig. 2) and the remainder produced on the west coast.

Identificação da fase sigma em uma junta soldada pelo processo TIG manual autógeno de um aço hiperduplex SAF 2707HD (UNS S32707) por difração de raios-x.

O aço inoxidável hiperduplex possui alta resistência a corrosão por pite em ambientes contendo cloretos, quando comparado a outros aços inoxidáveis comercialmente conhecidos. Possui boas propriedades mecânicas, com limite de escoamento superior a 700MPa e limite de resistência a tração em torno de 1000MPa. Essas propriedades o tornam muito atrativos para aplicações em ambientes contendo cloretos, e por isso tem tido destaque na indústria de óleo e gás, refinarias, plataformas offshore, etc. A liga hiperduplex é composta por uma estrutura bifásica, contendo proporções aproximadamente iguais de ferrita e austenita. Esse material possui boa soldabilidade, mas por ser termodinamicamente metaestável, em altas temperaturas pode ocorrer a precipitação de fases intermetálicas não desejáveis, o que resulta em perda de propriedades mecânicas e diminuição da resistência a corrosão. A fase sigma tem sido fortemente estudada, pois é comum sua precipitação nos aços inoxidáveis da família duplex durante o procedimento de soldagem se este não for muito bem controlado. A fase sigma precipita preferencialmente na fase ferrítica, devido a maior concentração de Cr e Mo, que são os elementos formadores da fase. A resistência a corrosão é reduzida e as propriedades mecânicas do material são alteradas o tornando frágil devido a presença da fase sigma. É formada entre 600C e 1000C e possui uma estrutura tetragonal complexa. O objetivo do trabalho foi identificar a possível presença da fase sigma na junta soldada do aço inoxidável hiperduplex SAF 2707 HD (UNS S32707) pelo processo TIG autógeno manual através da difração de raios-x. Nessa pesquisa, foram analisadas uma junta soldada do material pelo processo TIG autógeno manual com arco pulsado. Complementando o estudo foram analisadas seis amostras do aço inoxidável superduplex, sendo que cinco amostras sofreram tratamento térmico para a proposital formação da fase sigma. O refinamento do resultado da difração das amostras foi feito utilizando o método de Rietveld no software Topas Academic versão 4.1. O resultado da amostra soldada de hiperduplex apresentou as fases austenita, ferrita e alguns prováveis óxidos. Os resultados das amostras de superduplex tratadas termicamente apresentaram a fase sigma, conforme esperado na pesquisa, e as fases austenita e ferrita.

The U.S. Gulf of Mexico Party Boat Industry: Activity Centers, Species Targeted, and Fisheries Management Opinions

In addition to providing an overview of the party boat fishery in the U.S. Gulf of Mexico, a management-oriented methodology is presented that can be used elsewhere to assess regulatory impacts. Party boat operators were interviewed to determine species targeted, percent time committed to targeting each species, and opinions on current catch restrictions. Over two-thirds of the fieet was located on the west coast of Florida. Overall, most boats targeted <5 species. Four species accounted for 90 percent of the estimated effort by party boats in the U.S. Gulf of Mexico: Snapper; Lutjanus sp.; grouper, Epinephelus sp. and Mycteroperca sp.; amberjack, Seriola dumerili; and king mackerel, Scomberomorus cavalla. Party boat effort in Texas was devoted primarily to snapper, whereas in Florida most effort was devoted to snapper and grouper collectively. Party boat operators were diverse in their opinions of management regulations in force when interviewed. Results revealed why major opposition would he expected from Texas party boat operators for red snapper bag limits and other restrictions proposed by the Gulf of Mexico Fishery Management Council.

The U.S. Gulf of Mexico Charter Boat Industry: Activity Centers, Species Targeted, and Fisheries Management Opinions

The charter boat industry in U. S. Gulf of Mexico provides access to offshore fishing opportunities for about 570,000 passengers per year on 971 boats. A 25% random sample of charter boat operators was interviewed during 1987-88 to determine species targeted, percent time committed to targeting each species, and reactions to existing catch restrictions. Three-fourths of the charter boat fleet was in Florida, 13% in Texas, 5% in Louisiana, 4% in Alabama, and 2% in Mississippi. Responses were diverse regarding species focus within the region. Species of dominant importance included groupers, Epinephelus sp. and Mycteroperca sp. (Fla.); snapper, Lutjanus campechanus (Ala., Fla., Miss., and La.); king mackerel, Scomberomorus cavalla (Miss., Tex., Ala. and Fla.); spotted seatrout, Cynoscion nebulosus (Tex. and La.); and red drum, Sciaenops ocellatus (Tex. and La). Catch restrictions were generally supported with higher levels of opposition to restricted high effort fish and/or one fish or closed fishery limits.

Menhaden: The Resource, The Industry, and a Management History

PREFACE: Four species of menhaden, Brevoortia spp., are found along the Atlantic and Gulf of Mexico coasts of the United States. The Atlantic menhaden, B. tyrannus, is found from Nova Scotia, Can., to West Palm Beach, Fla.; the yellowfin menhaden, B. smithi, is found from Cape Lookout, N. C., to the Mississippi River Delta, La.;the Gulf menhaden, B. patronus, is found from Cape Sable, Fla., to Veracruz, Mex.; and the finescale menhaden, B. gunteri, is found from the Mississippi River Delta, La., to Campeche, Mex. Menhaden are euryhaline species that inhabit coastal and inland tidal waters. Spawning occurs principally at sea (in northern areas some spawning occurs in bays and sounds). Eggs hatch at sea and the larvae are moved to estuaries by ocean currents where they metamorphose and develop as juveniles.

Competing for the Recreational Dollar: An Analysis of the California Commercial Passenger-Carrying Fishing Vessel Industry

California has a large and diverse marine recreational fishery. Anglers on commercial passenger-carrying fishing vessels (CPFV's) harvest a substantial proportion of California's marine recreational fisheries landings, accounting for about 40 percent and 16 percent of the total 1986 marine recreational catch in southern and northern California, respectively (NMFS, 1987). In 1986, 459,369 CPFV anglers landed some 2,835,021 fish in southern California, while 200,925 CPFV anglers landed 1,240, 100 fish in central and northern California.