Condition of larval and juvenile red drum (Sciaenops ocellatus) from estuarine nursery habitats

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Red drum; Sciaenops ocellatus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.626.4567; http://www.tamug.edu/rooker/pdf/RookerMarBio97.pdf

Abstract RNA:DNA ratios of larval and juvenile red drum (Sciaenops ocellatus) collected from nursery habi-tats in the Aransas Estuary, Texas, in 1994 were quan-tified using a highly sensitive ethidium-bromide fluoro-metric technique. RNA:DNA ratios of wild red drum were evaluated by comparing individual values to a linear regression model derived for starved laboratory-reared red drum. Wild red drum were in relatively good condition with <5 % of the RNA:DNA ratios within or below the 95 % prediction interval of 4 to 5 d starved red drum. A multiple-regression model explained 54 % of the variability in the RNA:DNA ratio of wild red drum, and identified length and water temperature (midday) as significant factors. RNA:DNA ratios increased with fish length [.1.1 mm)1, over the size range investigated (5 to 20 mm)]. The effect of temperature on the RNA: DNA ratio was assessed on different sampling trips, and ratios increased with increasing temperature. Abundance of larval and juvenile red drum in the Aransas Estuary varied as a function of both habitat (shoal grass Halo-dule wrightii, turtle grass Thalassia testudinum) and site (Aransas Bay, Redfish Bay); however, no differences in RNA:DNA ratios were detected between habitats or between sites. It is postulated that the nutritional con-dition of newly settled red drum from the Aransas Es-tuary in 1994 was relatively high, and that starvation was of minor importance.