AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.
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To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab, Chionoecetes bairdi. Ovigerous females were reared in one of 3 treatments: control (ambient pH ~8.1), pH 7.8, and pH 7.5 for 2 years. Larvae in year 1 were from oocytes developed in the field whereas larvae in year 2 were from oocytes developed under acidified conditions. Larvae hatched each year, were also exposed to 3 pH treatments to examine starvation-survival, morphology, condition, and calcium/magnesium content. Approximately 300 larvae were stocked in multiple treatments for testing the effect of pH. Hatching success was measured as the total % of larval hatched from a full clutch while duration was the number of days over which hatching occurred. Hatching success did not differ among treatments in 2012 but varied between 46 to 87% in 2013 dependent on pH treatment. Larval mass was highest in pH 7.8 in 2012 and lowest in the control, however in 2013 the highest larval mass was in the control water. There were only small (not significant) changes in magnesium or calcium content among treatments in 2012 however, the reduction in both minerals at higher pH was greater in 2013. There was higher percent carbon and nitrogen contents in pH 7.5 larvae in 2013. The morphology of Tanner crab larval was assessed from 200 larvae stocked in multiple 2 L beakers. There was no effect of treatment on larval morphometrics. In 2012 and 2013, we examined if embryos developed under acidified conditions affected larval morphology by assessing 15 newly hatched larvae from each treatment. There was again no effect of treatment on larval morphometrics. Starvation survival experiments were performed in 1 L sized PVC inserts. In both years larvae from embryos that developed in pH 7.5 water survived about 3 days longer than those that developed in control water. However, in 2012 larvae from embryos that had developed in pH 7.8 water were similar to control larvae whereas in 2013 they were intermediate between the control and pH 7.5 larvae. The overall effects of treatment at the larval stage appeared to be better condition and initial survival at lower pH, however multiple years of treatment led to lower survival.
Effects of ocean acidification on hatch size and larval growth of walleye pollock (Theragra chalcogramma) from laboratory experiment studies from 2010-03-01 to 2011-05-31 (NCEI Accession 0125007)
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This dataset contains laboratory experiment data that were collected to examine the effects of ocean acidification on hatch size and larval growth of walleye pollock (Theragra chalcogramma). Rising atmospheric concentrations of CO2 are predicted to decrease the pH of high-latitude oceans by 0.3-0.5 units by 2100. Because of their limited capacity for ion exchange, embryos and larvae of marine fishes are predicted to be more sensitive to elevated CO2 than juveniles and adults. Eggs and larvae of walleye pollock (Theragra chalcogramma) were incubated across a broad range of CO2 levels (280-2100 matm) to evaluate sensitivity in this critical resource species. Slightly elevated CO2 levels (450 matm) resulted in earlier hatching times, but differences among egg batches were greater than those observed across CO2 treatments. Egg batches differed significantly in size-at-hatch metrics, but we observed no consistent effect of CO2 level. In three independent experiments, walleye pollock were reared at ambient and elevated CO2 levels through the early larval stage (to 30 days post-hatch). Across trials, there were only minor effects of CO2 level on size and growth rate, but fish in the ambient treatments tended to be slightly smaller than fish reared at elevated CO2 levels. These results suggest that growth potential of early life stages of walleye pollock is resilient with respect to the direct physiological effects of ocean acidification.
AFSC/RACE/GAP/Conrath: Rockfish habitat and productivity (Coral)
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The importance of high relief structure containing biotic habitat to rockfish and other species remains largely unknown. This data set was created to examine the importance of this habitat for Pacific ocean perch, northern rockfish, and dusky rockfish. These data were derived from four research cruises that occurred between May 2012 and December 2014. During the cruises, video data was recorded of habitat associations, plankton samples were collected, temperature profiles were recorded, and several types of biological samples were taken from trawl captured rockfish. These data will be recorded in several tables in an access database and video files will also be available.
AFSC/RACE/SAP/Foy: Effects of ocean acidification on embryo stages of Tanner crab: Kodiak Island, Alaska.
공공데이터포털
To study the effects of ocean acidification we examined the effects of ocean acidification on the embryo stages of the economically important southern Tanner crab, Chionoecetes bairdi. Ovigerous females were reared in one of 3 treatments: control (ambient pH ~8.1), pH 7.8, and pH 7.5 for 2 years. Embryos in year 1 were from oocytes developed in the field whereas embryos in year 2 were from oocytes developed under acidified conditions. Datasets associated with this study include Brooding Duration, Carbonate Chemistry, Embryo Morphology, and Embryo Stages. Embryo stages assessed monthly included detailed developmental stages from the prefuniculus formation through the prehatching stage. Embryo stages were not different among pH treatments. Embryo morphology included egg area, egg diameter, yolk area, yolk diameter, embryo area, eye area, and eye diameter. Each morphological characteristic varied according to pH treatment using a principal component analysis.
AFSC/RACE/EcoFOCI: NPRB project number 926: Assessing the condition of walleye pollock, Theragra chalcogramma, larvae in the eastern Bering Sea with muscle-based flow cytometry cell cycle analysis
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Walleye pollock are an important component of the eastern Bering Sea ecosystem due to their vast numbers and biomass and are of great commercial importance. Their recruitment in the eastern Bering Sea is not well understood but it is largely determined during the first year, so the larval stage may play a significant role. Starvation may contribute to the high and variable mortality that occurs during the larval stage so it is important to monitor and quantify it. This metadata describes data from laboratory and field studies conducted from 2009 to 2012 for NPRB project 926. The project completed the development of an assay using flow cytometric cell cycle analysis to assess the physiological condition of walleye pollock larvae, and applied it to field collected specimens. The use of RNA to improve the accuracy of the assay was also investigated, as well as the relationship between flow cytometric measurements and growth. Results showed that the overall classification accuracy of the assay (healthy or unhealthy) ranged between 75 and 83% depending on the type of cross-validation testing. A nuclear RNA variable (the ratio of the number of S phase nuclei to the number of high nuclear RNA content G1 phase nuclei) improved overall classification accuracy by 11% compared to a model without it. Unhealthy walleye pollock larvae were present in the southeastern Bering Sea in 2009, and this was most likely the result of cold environmental conditions affecting prey availability and larval feeding. In 2010, no unhealthy larvae were detected. This may be the result of less spatial coverage and smaller collections of larvae than in 2009, given that the environmental conditions were similar between years.