586 research outputs found
An analysis and treatment of labor and labor unions since 1800 in ten junior high school American history textbooks.
Thesis (M.A.)--Boston Universit
Seasonal variability in ichthyoplankton abundance and assemblage composition in the northern Gulf of Mexico off Alabama
Multiyear ichthyoplankton surveys used to monitor larval fish seasonality, abundance, and assemblage structure can provide early indicators of regional ecosystem changes.
Numerous ichthyoplankton surveys have been conducted in the northern Gulf of Mexico, but few have had high levels of temporal resolution and sample replication. In this study, ichthyoplankton samples were collected monthly (October 2004–October 2006) at a single station off the coast of
Alabama as part of a long-term biological survey. Four seasonal periods were identified from observed and
historic water temperatures, including a relatively long (June–October) “summer” period (water temperature >26°C). Fish egg abundance, total larval abundance, and larval
taxonomic diversity were significantly related to water temperature (but not salinity), with peaks in the spring,
spring–summer, and summer periods, respectively. Larvae collected during the survey represented 58 different
families, of which engraulids, sciaenids, carangids, and clupeids were the most prominent. The most abundant taxa collected were unidentified engraulids (50%), sand seatrout
(Cynoscion arenarius, 7.5%), Atlantic bumper (Chloroscombrus chrysurus, 5.4%), Atlantic croaker (Micropogonias undulatus, 4.4%), Gulf menhaden (Brevoortia patronus, 3.8%), and unidentified gobiids (3.6%). Larval
concentrations for dominant taxa were highly variable between years, but the timing of seasonal occurrence for
these taxa was relatively consistent. Documented increases in sea surface temperature on the Alabama shelf may have various implications for larval fish dynamics, as indicated by the presence of tropical larval forms (e.g., fistularids, labrids, scarids, and acanthurids) in our ichthyoplankton collections and in recent juvenile surveys
of Alabama and northern Gulf of Mexico seagrass habitats
Switching conditions and a synthesis technique for the singular Saturn guidance problem
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76180/1/AIAA-1970-965-334.pd
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