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Red Abalone (red + abalone)
Selected AbstractsAcute and chronic toxicity of nickel to marine organisms: Implications for water quality criteriaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2002John W. Hunt Abstract Acute and chronic toxicity tests were conducted to determine the effects of nickel on three U.S. west coast marine species: a fish (the topsmelt, Atherinops affinis), a mollusk (the red abalone, Haliotis rufescens), and a crustacean (the mysid, Mysidopsis intii). The 96-h median lethal concentration (LC50) for topsmelt was 26,560 mg/L, and the chronic value for the most sensitive endpoint in a 40-d exposure was 4,270 mg/L. The median effective concentration (EC50) for 48-h abalone larval development was 145.5 ,g/L, and the chronic value for juvenile growth in a 22-d exposure through larval metamorphosis was 26.43 mg/L. The mysid 96-h LC50 was 148.6 ,g/L, and the chronic value for the most sensitive endpoint in a 28-d, whole life-cycle exposure was 22.09 ,g/L. The abalone and mysid acute values were lower than other values available in the literature. Acute-tochronic ratios for nickel toxicity to the three species were 6.220, 5.505, and 6.727, respectively, which were similar to the only other available saltwater value of 5.478 (for Americamysis [Mysidopsis] bahia) and significantly lower than the existing values of 35.58 and 29.86 for freshwater organisms. Incorporation of data from the present study into calculations for water quality criteria would lower the criterion maximum concentration and raise the criterion continuous concentration for nickel. [source] Molecular paleoecology: using gene regulatory analysis to address the origins of complex life cycles in the late PrecambrianEVOLUTION AND DEVELOPMENT, Issue 1 2007Ewan F. Dunn SUMMARY Molecular paleoecology is the application of molecular data to test hypotheses made by paleoecological scenarios. Here, we use gene regulatory analysis to test between two competing paleoecological scenarios put forth to explain the evolution of complex life cycles. The first posits that early bilaterians were holobenthic, and the evolution of macrophagous grazing drove the exploitation of the pelagos by metazoan eggs and embryos, and eventually larvae. The alternative hypothesis predicts that early bilaterians were holopelagic, and new adult stages were added on when these holopelagic forms began to feed on the benthos. The former hypothesis predicts that the larvae of protostomes and deuterostomes are not homologous, with the implication that larval-specific structures, including the apical organ, are the products of convergent evolution, whereas the latter hypothesis predicts homology of larvae, specifically homology of the apical organ. We show that in the sea urchin, Strongylocentrotus purpuratus, the transcription factors NK2.1 and HNF6 are necessary for the correct spatial expression profiles of five different cilia genes. All of these genes are expressed exclusively in the apical plate after the mesenchyme-blastula stage in cells that also express NK2.1 and HNF6. In addition, abrogation of SpNK2.1 results in embryos that lack the apical tuft. However, in the red abalone, Haliotis rufescens, NK2.1 and HNF6 are not expressed in any cells that also express these same five cilia genes. Nonetheless, like the sea urchin, the gastropod expresses both NK2.1 and FoxA around the stomodeum and foregut, and FoxA around the proctodeum. As we detected no similarity in the development of the apical tuft between the sea urchin and the abalone, these molecular data are consistent with the hypothesis that the evolution of mobile, macrophagous metazoans drove the evolution of complex life cycles multiple times independently in the late Precambrian. [source] Cover Picture: Acceleration of Calcite Kinetics by Abalone Nacre Proteins (Adv. Mater.ADVANCED MATERIALS, Issue 22 200522/2005) Abstract Abalone utilizes a system of macromolecular matrices and soluble proteins to produce beautiful and mechanically robust shells. The cover shows work by Qiu and co-workers reported on p.,2678, in which AP8 proteins isolated from the shell of red abalone are shown to alter the growth of calcite both by accelerating the rate and modifying the shape from the simple rhombohedra seen in the upper left of the scheme to the more complex form seem in the lower right. The changes are made manifest at an atomic scale through alterations in the growth speed and shape of the atomic steps that form the growth hillocks (background). [source] Comparative performance of juvenile red abalone, Haliotis rufescens, reared in laboratory with fresh kelp and balanced dietsAQUACULTURE NUTRITION, Issue 2 2009Z. GARCIA-ESQUIVEL Abstract Juvenile Haliotis rufescens were reared in the laboratory in order to investigate the extent to which fresh kelp and formulated feeds with 250 g kg,1 (25P) and 380 g kg,1 protein content (38P) affected their growth rate, gut residence time (GRT), food consumption (C), food conversion ratio (FCR) and digestibility. Abalone from 38P attained the highest growth rate (70.5 ± 4.2 ,m day,1; 98.3 ± 6.95 ,g day,1), followed by 25P (47.9 ± 2.79 ,m day,1; 67.4 ± 2.82 ,g day,1) and kelp (23.6 ± 3.36 ,m day,1; 28.2 ± 4.11 ,g day,1). No significant differences were observed in consumption rate among treatments (0.61,0.68% body weight per day), yet kelp-fed abalone exhibited higher FCR (2.44), protein efficiency ratio (4.42), and apparent digestibility of dry matter (69.5%), protein (69.8%) and gross energy (79.2%) than 38P organisms (59.8, 62.4 and 62.2%, respectively). They also showed longer GRT (23.1 ± 0.93 h). This study demonstrated that formulated diets with 250 g kg,1 and 380 g kg,1 protein inclusion can sustain higher growth rates of juvenile H. rufescens than fresh algae. These differences seem to be due to the amount of dietary protein. Kelp meal appears to improve the consumption and digestibility of balanced diets, and its inclusion in formulated diets is recommended. [source] Growth performance of weaning red abalone (Haliotis rufescens) fed with Macrocystis pyrifera plantlets and Porphyra columbina compared with a formulated dietAQUACULTURE RESEARCH, Issue 15 2009Jorge Hernández Abstract A feeding experiment was carried out to evaluate two natural diets versus a formulated feed on the performance of weaning red abalone Haliotis rufescens. Four treatment diets were then investigated: a formulated diet; plantlets from culture Macrocystis pyrifera, Porphyra columbina from natural beds; and a mixed diet consisting of a blend of fresh P. columbina together with the formulated diet. This study was performed in a shallow aquaculture system with a horizontal water flow. After 90 days, significant differences were observed between treatments. The highest growth was obtained with Porphyra (3.3 mm month,1), followed by the mixed diet (2.6 mm month,1), then Macrocystis (2.1 mm month,1) and lastly the formulated diet (1.4 mm month,1). Moreover, after the diets were tested for stability and remnant nutrients after a 12-h water immersion, a positive trend appeared to be related to the protein/energy (P:E). It is concluded that fronds of P. columbina resulted in the best diet for weaning H. rufescens under horizontal water flow systems, even if apparently the water stability of the formulated diet had a negative impact on abalone performance, particularly due to a poor nutrient retention capacity. Therefore, formulated diets should be improved before being recommended for weaning red abalone. [source] | |||||||||||||