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Ornamental fish production is among the leading cash crops of the United States of America aquaculture economy, and retail value of the fish trade is worth approximately US$l,000 million. However, few studies exist to document this trade. Using import and export documents we report trends in total values for the U.S. trade in ornamental fish. Also, we determined the number and value of the most commonly imported ornamental fish. In 1992, approximately 201 million fish valued at $44.7 million were imported into the U.S. The port of Los Angeles handled 39% of all trade activity, Miami 22%, New York 16%, Tampa 6%, and Honolulu 6%. Freshwater fish accounted for approximately 96% of the total volume and 80% of the value of the imports. Most freshwater ornamental fish were farm‐raised and imported from Southeast Asia. Most U.S. exports of ornamental fish were cultured in the state of Florida. Although saltwater fish had a high market value (20% of the declared value of the imports), the volume of these fish was only 4%. Most imported and exported saltwater ornamental fish were collected from the wild. Of the 1,539 species declared as ornamental fish, 32 species dominated the trade. These were all of freshwater origin. The guppy Poecilia reticulala and neon tetra Paracheirodon innesi were the most popular ornamental fish kept in U.S. households. The average prices paid for imported ornamental freshwater fish were 45 cents for egg layers and 22 cents for live bearers. The results of this study document the importance of the ornamental fish industry and identifies the most valuable species in the trade for potential domestic culture and protection in the wild.

Primordial germ cell (PGC) specification occurs either by induction from pluripotent cells (epigenesis) or by a cell-autonomous mechanism mediated by germ plasm (preformation). Among vertebrates, epigenesis is basal, whereas germ plasm has evolved convergently across lineages and is associated with greater speciation. We compared protein-coding sequences of vertebrate species that employ preformation with their sister taxa that use epigenesis and demonstrate that genes evolve more rapidly in species containing germ plasm. Furthermore, differences in rates of evolution appear to cause phylogenetic incongruence in protein-coding sequence comparisons between vertebrate taxa. Our results support the hypothesis that germ plasm liberates constraints on somatic development and that enhanced evolvability drives the evolution of germ plasm.

From 1986 to 1994, we collected 3,098 Gulf of Mexico sturgeon (Acipenser oxyrinchus de sotoi) during their spring migration from the Gulf of Mexico to the Suwannee River, Florida. We estimated population size and described migratory and seasonal growth patterns of sturgeon in the Suwannee River, using data from tag returns, movement of ultrasonic‐lagged fish and weight records. Population size estimates for 3.0‐ to 81.0‐kg Gulf of Mexico sturgeon in the Suwannee River ranged from 1,504 to 3,066 fish. Sturgeon migrated from the Gulf of Mexico into the Suwannee River from mid‐February to early May. Fish moved upstream and remained within a 2‐km upstreamdownstream “home” area. These sites were closely associated with undenvater springs that discharge into the river. Sturgeon migrated downstream and into the Gulf of Mexico in October and November. In the Gulf of Mexico, ultrasonic‐tagged fish were located in the Suwannee Sound area just north of Cedar Key, Florida. On an annual basis, fish gained an average of 20% of their body weight while in the Gulf of Mexico and lost about 12% of their weight during their stay in the Suwannee River. We observed movement of tagged sturgeon between the Suwannee and Apalachicola Rivers.

Although low levels of dietary mannanoligosaccharide (MOS) supplementation have been shown to increase weight gain, decrease feed conversion, and stimulate intestinal villi growth in domestic mammals and birds, the responses of aquacultural species to MOS have not been studied. We examined the effects of MOS supplementation on the growth of and digestive tract morphology in Gulf sturgeon Acipenser oxyrinchus desotoi. There were no differences in growth performance (as measured by condition factors, specific growth rates for weight and fork length, and feed conversion ratios), gross gastrointestinal morphology (gut length and spiral valve length), or spiral valve villi structure (villus length, width, and density) between fish fed control and MOS‐supplemented diets. However, in light of the promising results obtained by similar studies across a wide range of animals, dietary MOS supplementation in other aquacultural species merits further investigation.

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