Determination of the burrow shapes of Cardisoma guanhumi on Vieques,Puerto Rico

Objective:To determine the burrow morphology of Cardisoma guanhumi and to determine if a battery-powered fiber optic camera could be used to investigate these burrows.Methods:A portable fiber optic camera was used to investigate 116 active burrows.All burrows were categorized according to shape.The diameter of each burrow was also recorded and biomass calculations were completed at each study site.Results:Analysis showed that different study sites were more likely to have particular burrow shapes than expected.Three main types of burrows were classified as horizontal slide,short and shallow,and inverted-S.A Pearson Chi-square analysis revealed that burrow shape was not equally distributed across study sites(χ^(2)=61.05,df=18,P<0.0001).Biomass calculations showed that different sized animals inhabited different study sites(ANOVA;df=7,MS=158.3,F=13.9,P<0.0001).The fiber optic camera was useful in determining burrow morphology and occupancy non-destructively.Conclusions:As the locations of juvenile individuals of this species are poorly known,and the species is both ecologically and economically important where it occurs,a greater understanding of burrow morphology and size segregation may help agencies be responsible for managing this natural resource to do so effectively.

Seasonal abundance of Pyrodinium bahamense(order Peridiniales,family Gonyaulacaceae)in Mosquito Bay,Vieques,Puerto Rico

Objective:To determine the presence of consistent spatial or temporal patterns to the abundance of Pyrodinium bahamense(P.bahamense)in Mosquito Bay,Vieques,Puerto Rico.Methods:Measurements of dissolved oxygen,pH,salinity,water temperature,tide level,wind speed,and density counts of P.bahamense were taken at six sites in the bay over approximately one year.The data were analyzed statistically to determine if spatial or temporal patterns were present.Results:There were statistically significant patterns of P.bahamense seasonally,which was similar to other studies done in other subtropical locations with phytoplankton.Also,trends were seen that rain events caused short-term increases in abundance and shallow areas of the bay had lower abundance than that of deeper areas.The average number of organisms from 736 samples was 26.8 per mL.The average water temperature was 29.0℃,the average salinity was 36.8 ppt,the average pH was 8.11,and the average dissolved oxygen level was 4.27 mg/L.Conclusions:The abundance of P.bahamense varies seasonally over shorter time periods.The abundance also varies over a few meters in small coastal bays.This information indicates that economically important bioluminescent bays are vulnerable to changes in freshwater input,water temperature,water circulation patterns and possibly the nutrient inputs from the land surrounding such bays.