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. BLAGRRA Line Transects Rapid Surveys for Ecological Emergencies www.agrra.org © E. Muller St. John, USVI Sept. 2005.

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Presentation on theme: ". BLAGRRA Line Transects Rapid Surveys for Ecological Emergencies www.agrra.org © E. Muller St. John, USVI Sept. 2005."— Presentation transcript:

1 . BLAGRRA Line Transects Rapid Surveys for Ecological Emergencies © E. Muller St. John, USVI Sept. 2005

2 BLAGRRA Line Transects For rapidly assessing ecosystem-level changes in total live coral cover during, and following, mass bleaching events, outbreaks of disease, or other acute ecological perturbations. Permission is granted to use the photographs in this presentation with the BLAGRRA Program and, with attribution, for other valid educational projects. All other uses are strictly prohibited.

3 Rationale © E. Muller Mass bleaching events and some diseases cause discoloration of live coral tissues. Elevated levels of coral mortality characterize ecological emergencies (severe environmental perturbations) in coral reefs.

4 Bleaching Categories Normal, Pale, Bleached: should be specific for the species at the particular location & habitat © P. Dustan pale normal © T. Turner Deep coral (Montastraea) pale bleached © S. Zea Shallow coral (Montastraea) Close-up

5 New Mortality White White skeletons are intact (unless live tissues have just been bitten by a fish or abraded), with no sediment, algae, or other visible cover. Would have died within the previous seconds to days. Conspicuous during outbreaks of disease, bleaching-related mortality events, and just after hurricanes or other large-scale perturbations. new mortality © P. Dustan Diseased coral (Mycetophyllia) Close-up live tissues

6 © G. Schmahl © P. Dustan Close-up New mortality: dead & white Bleached: translucent tissues without visible algal pigments Easily confused! and © R. Ginsburg Close-up © L. Benvenuti © C. Rogers

7 Transitional Mortality Skeletons are mostly intact and covered with a thin layer of sediment, or biofilms, or tiny, multi-colored turf algae (unless they have just been bitten by a fish or abraded). Would have died within the previous days to months. Conspicuous after outbreaks of disease, bleaching-related mortality events, hurricanes or other perturbations. Turf algae on coral (Acropora palmata). © P. Dustan transitional mortality Close-up new mortality

8 Post-Bleaching Mortality Stony corals may survive a bleaching event but later succumb to disease or from unknown causes. Severe bleaching: tissues survive Monitored coral (Montastraea annularis) in St. John. Post-bleaching disease: tissues die © J. Miller Sept. 2005Nov. 2005

9 Relevance to Managers Sites can be rapidly and repeatedly surveyed over a large spatial scale by easily trained volunteers or staff to capture the immediate + any delayed effects of a given mortality event. Results can be compared to mortality levels occurring during “routine” environmental conditions. For example: during a severe bleaching event, mortality from bleaching is scored as new mortality. Several months later, when this initial mortality has shifted into the transitional mortality category, any ongoing, post-bleaching mortality is scored as new mortality.

10 . What else can you see here? © L. Benvenuti Stressed coral (Colpophyllia natans) black-band disease transitional mortality new mortality bleached tissues

11 Personnel 1-2 experienced divers (can be volunteers). Field Equipment Clipboard or slate with BLAGRRA Line UW-V2.0 datasheet printed on UW paper & pencils. 10-m long, lead-core rope, with marks at 0-m and at 10-m, and tie-off loops at each end. 50-cm PVC measuring pole marked in 10-cm increments + a 15-cm or 30-cm metric ruler. 25 cm x 25 cm PVC quadrat around which to wrap the line. Dive thermometer or other temperature recording device. \ See BLAGRRA Surveys & Gear-V2.0.pdf for Equipment details at:

12 Surveys Stratify reefs by zone and habitat. Randomly sample sites (at least 5/habitat, total number to vary with spatial extent of the habitat) for a representative assessment of reef condition in the area affected by the perturbation, and/or Strategically choose any sites of special interest for survey (e.g., within and outside an MPA). Survey before (if possible), during, and at intervals after, the mortality event until conditions return to “normal.” See BLAGRRA Surveys & Gear-V2.0.pdf for Survey details at:

13 Method Try to record bottom temperature at site. Haphazardly set line; note start and end depths. Swim line; measure intercept lengths of all live coral tissues as normal, pale, or bleached between the 0-m and 10-m marks. (Sum = live coral cover.) Re-swim line and measure intercept lengths for any new mortality and any trans (= transitional) mortality. (Sum = effects of “recent” perturbations.) Record any interesting observations in Comments. Repeat for a total of 10 transects/site. See BLAGRRA Line UW Datasheet-V2.0 for UW Datasheet & Method details at:

14 Note: individual corals are not noted nor identified to species. Part of a BLAGRRA Line UW-V2.0 Datasheet

15 Sum all cover category numbers for each transect. Every day, enter all data for each dive in a separate copy of the BLAGRRA Lines Data Entry-V2.0 spreadsheet. Check for accuracy. Store UW datasheets and data entry files in secure locations. Send data entry files to for processing, archiving, and possible posting online at Part of a BLAGRRA Line Data Entry-V2.0 Spreadsheet

16 BLAGRRA Line Transects During an ecological emergency, go directly to: Optional: to rapidly assess stony coral mortality at the population-level during ecological emergencies, see BLAGRRA Belt Transects at: For more about the AGRRA Project, see: Prepared for the AGRRA Project by: Judith C. Lang, September 2010


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