Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Deployments
• Project Information
• Funding

This dataset is from a manipulative experiment the relative competitive abilities of juveniles of three closely related species of reef fish (bird wrasse, Gomphosus varius; fivestripe wrasse, T. quinquevittatum; and the sixbar wrasse, Thalassoma hardwicke).

Site locations:

Teaharoa West: 17 28.397’S, 149 47.592’W
Teaharoa East: 17 28.260’S, 149 47.118’W
Vaipahu: 17 28.772’S, 149 50.879’W

For additional data, please see Related Datasets section. 

Related Datasets:

• Geange_et_al_2013 Competitive Hierarchies: https://www.bco-dmo.org/dataset/727026
• Geange_et_al_2013 Competitive Hierarchies Background Community: https://www.bco-dmo.org/dataset/727058
• Geange_et_al_2013 Competitive Hierarchies Lengths: https://www.bco-dmo.org/dataset/727043
• Geange_et_al_2013 Competitive Hierarchies Spatial Covariance: https://www.bco-dmo.org/dataset/727076 (current page)

To determine the in situ spatial covariation of superior and inferior competitors, we surveyed the density of the 3 species at 3 locations. Each location consisted of 2 sites that were arrayed perpendicular to the reef crest: a ‘crest’ site (~95 m shoreward of the reef crest) and a ‘lagoon’ site (~190 m shoreward of the reef crest). At each site, we haphazardly selected 16 patch reefs of similar surface area (mean ± SD): 8.40 ± 4.91 m2, and 8.23 ± 4.06 m2, for the crest and lagoon locations, respectively. On each reef and the surrounding 1 m halo, we counted juveniles of the 3 focal species, which we converted to densities. Juveniles were defined as individuals with SL < 25 mm. Surveys were conducted between 08:00 and 16:00 h.

Abundance of Thallasoma Hardwicke, T. quinquevitattum and Gomphosus varius have been converted to densities.

BCO-DMO Processing:

• added conventional header with dataset name, PI name, version date
• modified parameter names to conform with BCO-DMO naming conventions
• appended the fields lat and lon to include the coordinates for each site, accompanying the data.

Description from NSF award abstract:
Ecologists have long been interested in the factors that drive spatial and temporal variability in population density and structure. In marine reef systems, attention has focused on the role of settlement-the transition of pelagic larvae to a benthic stage-and on density-dependent processes affecting recently settled juveniles. Recent data suggest that co-variance in settlement and subsequent density-dependent survival can obscure the patterns of density dependence at larger scales, a phenomenon called cryptic density dependence. This research will explore the mechanisms that underlie the spatial covariance of settlement and site quality - a process that has received little attention in the standard paradigm. These mechanistic studies of cryptic density dependence will facilitate the development of new frameworks for fish population dynamics that incorporate larval ecology, habitat quality, density dependence, life history, and the patterns and implications of spatial covariance among these factors. More generally, the work provides a specific empirical context, and a general theoretical treatment, of cryptic heterogeneity (hidden individual variation in demographic rates).

Note: Drs. Craig W. Osenberg and Ben Bolker were at the University of Florida at the time the NSF award was granted. Dr. Osenberg moved to the University of Georgia during the summer of 2014 (current contact information). Dr. Bolker moved to McMaster University in 2010 (current contact information).