In situ observations of the introduced predatory grouper roi (Cephalopholis argus) were taken semi-annually within the coral reef ecosystem of Puako, northwest side of the Island of Hawaii October 2010 - July 2012. Visual fish transects were made at a depth range of 10-20 m. Tow board and standard visual belt transects were employed at control, reference, and treatment sites. Data include biometrics (length and weight) and biomass of roi, as well as an assemblage of other fish and feed guilds. Additional data on the movement of roi within the Puako area were collected using a fish tagging program followed by surveys for recapture and resighting.
NODC Accession 0082197 contains similar data from November 2010 - June 2011. There is some overlap of data within 0082197 and the present accession.
Sixty-seven roi from the areas adjacent to the defined removal sites were captured in nets with diver-deployed handline and barrier nets, and tagged with a standard Hallprint tagging gun and t-bar tag. Tagging events were opportunistic from February to October 2011. Movements of tagged roi into the cleared area were noted during subsequent monitoring events, ranging from June 2011 to July 2012. The geographic coordinates of tagged and recaptured roi were obtained by matching the recorded time of capture/re-sight with the logged GPS time-track.
2) Roi Removal Local fishers were contracted to assist with roi removal at the treatment reef (13,366 m2) during April and May of 2011. Spear-fishing for roi occurred over the course of 11 days. Fishers removed roi from the treatment reef with the number of fishers and hours fished recorded. Roi were collected, counted, sized, and weighed on site. Each diver's individual effort in dive time was recorded, along with the number of roi dispatched. Dive times ranged from 37 min to 56 min, and number of dives ranged from 1-3 per day.
3) Fish Assemblage Monitoring A Before-After-Control-Impact experimental design was used to assess changes in reef fish assemblages associated with roi removal activities (Green 1979). Forty-seven permanent transect were established at randomly selected sites of similar habitat in removal areas and adjacent control sites. The study area for each of three study sites lie on Porites compressa dominated habitat types with similar habitat complexity.
At these sites, visual fish transects were conducted following West Hawaii Aquarium Project (WHAP) survey protocols for 5 m x 25 m fish transects (Tissot et al. 2004), whereby two scuba divers swim in tandem along 25-m fixed replicate transect at a constant speed (15 minutes per transect). All fishes observed within the transect were identified to the lowest possible taxon and placed in size bins (0.0-4.9 cm TL, 5.0-9.9 cm TL, 10.0-14.9 cm TL, etc.). Divers were previously trained in visual underwater size estimation techniques based on practice with various lengths of fish models that were later collected and measured.
Two rounds of data were collected from the suite of removal and control sites during November 2010 and March/April 2011, before any roi removal was implemented in order to establish baseline conditions at these sites (data within NODC accession 0082197). Surveys were conducted again one month after roi were removed from the experimental sites during June and November 2011 and then again in June 2012, six-months and one-year after roi removal. This quarterly monitoring schedule was implemented for the first year, and surveys will be conducted bi-annually for the duration of the project, which is expected to continue through 2015. The power for this design was 0.877 for a one-way ANOVA for the prey taxa abundance following roi removal after six-month. Power was calculated in Minitab16 using the maximum difference between means, standard deviation, and sample size (each replicate transect) to calculate the power of the data set. With additional post-removal surveys in the coming years, temporal changes on the individual transects will become the replication of this repeated measures BACI design.
4) Roi Distribution Monitoring In order to assess roi population distributions throughout the wider region, a fish census focusing solely on roi was conducted bi-annually in removal and control areas. This census was conducted using tow-boards following NOAA Coral Reef Ecosystem Division (CRED) protocols, and followed isobaths from 10 m-30 m, covering a total area of 0.4 km2. These census rounds took place in April, June, and November 2011 and in June 2012. Two divers were deployed along a 50-m tow line, each with a planning board; one diver had a telegraph system to communicate with the boat. Divers were towed at a constant speed along a set bearing. Maintaining depth 3 m from the benthos, divers recorded each roi sighting of within 5 m either side of the straight line trajectory. Communication was maintained between diver pairs both above water and during the survey, to ensure that roi were not double counted. Each roi sighting was recorded along with the roi body-size and time of sighting. The roi sight time was later matched to the boat GPS log of time at geographic location. The offset from the boat GPS location to diver location along the tow line was calculated by the formula a2+b2=c2, where a=depth, c=tow-line length, and b=distance from the boat GPS location.
INSTRUMENT TYPES: visual observations hand held GPS
REFERENCES: Green RH. 1979. Sampling design and statistical methods for environmental biologists. Wiley Chichester.
Tissot BN, Walsh WJ, Hallacher LE. 2004. Evaluating effectiveness of a marine protected area network in West Hawaii to increase productivity of an aquarium fishery. Pacific Science 58:175-188.
0-data/ This directory contains the files as provided by the contributor
filename: Puako_Roi_HCRI_Annual_Birkeland_Giddens_8_29.pdf format: PDF content: NOAA Project Final Report
filename: Puako_roi_census_Birkeland_Giddens_2012.xlsx format: MS Office Excel 2007 content: Roi census data column: Date of dive content: month/day/year of observation column: Diver name content: Initials of diver CHW: Chad Wiggins JLG: Jonatha Giddens KAS: Kosta Stamulous KSP: Kydd Pollock RJA: Russel Amimoto ZRC: Zach Caldwell column: Census content: 1: April 2011, 2: June 2012, 3: Nov 2011, 4: June 2012 column: Number roi content: count of roi sized and weighed, always 1 column: Size Roi (cm) content: estimated length fin to snout column: Weight (g) content: estimated weight based on length
filename: Puako_roi_fish_assemblage_Birkeland_Giddens_2012.xlsx format: MS Office Excel 2007 content: belt transects and tow-boards to observe the community fish column: Location content: observation site, either Treatment, Control, or Reference column: Survey_round content: chronologically ordered survey of given transect location column: Month content: date of observation column: Transect content: transect ID column: Taxa content: taxa type column: Family content: biological classification within family column: Feed Guild content: category of the group of species that exploit similar resources column: Max_TL content: maximum total length of given taxa, from tip of snout to tip of tail fin, cm column: Length (cm) content: length of individually observed taxa, snout to fin, cm column: Length_weight (g) content: estimated weight (g) of the given length column: Count content: how many seen on transect column: Biomass content: total biomass of taxa on transect (g/125m2)
filename: Puako_roi_tag_Birkeland_Giddens_2012.xlsx format: MS Office Excel 2007 content: Roi tagging and movement data, details given below under 1-data
1-data/ This directory contains files generated by NODC. Most files are comma-separated version (CSV) text exports of the unique sheets of the original MS Excel files in 0-data/.
There is one file for each sheet within each original MS Excel file. The file name is the original MS Excel filename root appended with the individual sheet name. For files that had only one sheet, then the root name is the same.
file: filename: Puako_Roi_HCRI_Annual_Birkeland_Giddens_8_29.pdf format: PDF/A content: this is a redundant copy of the report in /0-data, though in the PDF/A (archive) format, a standard for archives.
file: Puako_roi_census_Birkeland_Giddens_2012.csv format: ASCII text comma-separated version content: defined in 0-data
file: Puako_roi_fish_assemblage_Birkeland_Giddens_2012.csv format: ASCII text comma-separated version content: defined in 0-data
file: Puako_roi_tag_Birkeland_Giddens_2012_Roi_tag.csv format: ASCII text comma-separated version content: sheet 1, Tagging data column: Date content: mm/dd/yyyy, date tagged column: Group content: tagging zone (physical location, 1-6) column: Lat content: latitude decimal degrees from GPS column: Long content: longitude decimal degrees from GPS column: TL (cm) content: total length tail fin to snout in cm column: SL (cm) content: standard length (from snout to the start of the caudal peduncle) in cm column: Weight(kg) content: weight of tagged fish in kilograms column: Tag_number content: ID written on the tag column: T-color content: color of tag column: T-position content: location on fish of tag
file: Puako_roi_tag_Birkeland_Giddens_2012_Roi_recapture.csv format: ASCII text comma-separated version content: sheet 2, data on recaptured fish column: Fish_ID_tag content: tag for fish identification column: Tag_number content: tag number for fish identification column: Date_tag content: mm/dd/yyyy, date tagged column: Time_tag content: hh:min tagged Hawaii Standard Time column: Lat_tag content: latitude of tagged fish measured by GPS column: Long_tag content: longitude of tagged fish measured by GPS column: Date_capture content: mm/dd/yyyy, date captured column: Lat_capture content: latitude of captured fish measured by GPS column: Long_capture content: longitude of captured fish measured by GPS column: Tag_number content: ID written on the tag (for color coded tags) column: T-color content: color of tag
file: Puako_roi_tag_Birkeland_Giddens_2012_Roi_Re_sight.csv format: ASCII text comma-separated version content: sheet 3, data on recaptured fish column: Date content: mm/dd/yyyy, date sighted column: Buffer content: buffer zone of re-sight column: Direction content: direction toward which fish moving column: Group content: tagging zone 1-6 column: Date_resight content: mm/dd/yyyy of resight column: Resight_Lat content: latitude from GPS of resighting column: Resight_Long content: longitude from GPS of resighting column: Tag_Position content: location on fish of sighted tag column: Group content: tagging zones 1-6