|Lasker, Howard||State University of New York at Buffalo (SUNY Buffalo)||Principal Investigator|
|Biddle, Mathew||Woods Hole Oceanographic Institution (WHOI BCO-DMO)||BCO-DMO Data Manager|
This dataset contains octocoral colony heights measured during transect surveys at four sites on the south shore of St. John, US Virgin Islands in November 2017 following Hurricanes Irma and Maria.
All sites were located at 6 to 9 meters depth.
Censuses at East Cabritte, Europa and Tektite were based on 50x10m areas that were arbitrarily selected and permanently marked with stainless steel eyebolts at the corners of the sites. A total of six transect lines, also marked with eyebolts, were laid out at 10 m intervals. All octocorals present in 1 x 1 m quadrats along the 10-meter long transects were scored. In 2014 ten quadrats were surveyed along each line. In 2015 and 2016 ten quadrats were scored along each transect line at Europa and Tektite and five randomly chosen quadrats were surveyed at East Cabritte. The transect identifier "transect_pos" has values 0, 10, 20, 30, 40 or 50 which represent position in meters within the 50x10 survey area corresponding to each of the 6 transects (e.g. 20 = 20m).
The census at Booby Rock was conducted in a single day in which 2 transects were randomly placed along a 50 m line that was arbitrarily placed on a constant depth contour. Only 4 1x1 m quadrats were surveyed along each transect. The transect identifier (transect_pos) for transects at Booby Rock refers to position along the 50 m line.
Identifications were based on traits visible in the field, and samples of representative colonies were collected for further analysis in cases in which field identification was uncertain. Sclerites from those samples were examined for species identification.
Colony heights were measured as the maximum distance from the base of the octocoral colony until the farthest tips of the branch (i.e. not necessarily perpendicular to the substrate). All measures rounded to the nearest cm with the exception of 5 cm which only includes colonies >= 5 cm. Starting in 2016, measures less than 5 cm reflect colonies with thick branches which could only have <5 cm heights due to partial mortality.
Two height measures are present, height of living tissue, which only includes that part of the axis with living tissue and total height which is the distance from the base to the tip of the tallest branch regardless of whether the tips or base had living tissue. (Only colonies with some living tissue were measured).
Species names for field_codes in this dataset can be found in the related dataset: https://www.bco-dmo.org/dataset/733063
These data are a continuation of BCO-DMO project "Ecology and functional biology of octocoral communities" (http://www.bco-dmo.org/project/562086)
BCO-DMO Processing Notes:
|Date||Day - Month - Year on which data were collected.||unitless|
|Transect_Position||Transects positioned in a marked 50x10m area with stainless steel eye bolts marking each corner and each of the 6 transect. Transects were 10m long across the 50x10m area. So there were 0m; 10m; 20m; 30m; 40m; 50m.||meters (m)|
|Side_of_transect||Side of the transect tape (Left or Right) orientation looking towards open ocean with the nearest shore to the back.||unitless|
|Meter_on_transect||From 0m to 9m. 1x1m quadrats were positioned randomly along the 10 m transect. The values refer to the position of the "shoreward" corner of the quadrat. Thus "0"refers to the quadrat placed between the 0 and 1 meter marks||meters (m)|
|Species_code||Octocorals species acronyms. Field identifications of Pseudoplexaura flagellosa and P. wagenaari are difficult among small colonies and for analysis purposes the two species should be lumped as a single group. Field identifications of Eunicea mammosa E. laxispica and E. succinea are sometimes difficult s and for analysis purposes the two species should be lumped as a single group. LINES WITH NO SPECIES ENTRY IDENTIFY QUADRATS IN WHICH NO OCTOCORALS WERE PRESENT- This is also noted in the comments as "No colonies present"||unitless|
|Height_of_living_tissue||Maximum distance from the base of the octocoral colony until the farthest tips of the longest branch with living tissue (i.e. not necessarily perpendicular to the substrate). All measures rounded to the nearest cm with the exception of 5 cm which only includes colonies >= 5 cm. Measures less than 5 cm reflect colonies with thick branches which could only have||centimeters (cm)|
|Total_Height||total height||centimeters (cm)|
|Genus_Species||Full species name||unitless|
|lat||latitude in degrees north||decimal degrees|
|lon||longitude in degrees east||decimal degrees|
|Comments_1||Comments. C. gibbosum denotes the presence of Cyphoma giibbosum a grazing snail that strips living tissue from octocoral colonies.||unitless|
|Comments_2||Numbers refer to sample numbers of 4 cm dried tissue specimens collected for species identification.||unitless|
R/V F.G. Walton Smith
|Start Date|| |
|End Date|| |
Transect surveys at four sites on the south shore of St. John, US Virgin Islands.