Table of Contents

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

This dataset includes the predatory success of larval clownfish (Amphiprion ocellaris) between 1 and 14 days post-hatch. They were presented with nauplii, copepodites, and adults of the copepod Parvocalanus crassirostris.

Related Reference:
Jackson, J. M. and Lenz, P. H. (2016). Predator-prey interactions in the plankton: larval fish feeding on evasive copepods. Scientific Reports, 6, 33585; doi: 10.1038/srep33585.

All experiments were approved by the University of Hawaii’s Institutional Animal Care & Use Committee (IACUC) under protocol #1045. For determination of growth, larval Amphiprion ocellaris were euthanized using a solution of 0.06 g/ml Ethyl 3-aminobenzoate methanesulfonate salt (MS222) (Sigma-Aldrich Inc., Saint Louis, MO, USA; catalog no. A5040-25G), preserved in a solution of 5% formalin in seawater, and measured for total length and jaw size within one week of fixation.

Behavioral observations were made of predator-prey interactions between larval fish and copepod prey under conditions that were similar to the feeding conditions in the rearing tank in terms of prey numbers and fish density.  For each trial, 10 A. ocellaris larvae were transferred from the rearing tank into the observation chamber (18 x 18 x 10 cm aquarium made of Plexiglas) filled with 3 L of filtered seawater (Whatman filters, GF/C).  The fish larvae were allowed to acclimate for 15 minutes, before adding the 3000 prey.   Each experimental trial lasted for 60 minutes and prey densities declined by 25% or less during this time.  During the trial, a CCTV video camera (Panasonic Corporation, Kadoma, Osaka, Japan; model WV-BP310) equipped with a Nikkor 50 mm lens (Nikon Corporation, Shinjuku, Tokyo, Japan; model 1433) recorded continuously and stored the recording on a digital high definition videocassette recorder (Sony Corporation, Minato, Tokyo, Japan; model GV-HD700).  The camera lens was positioned 0.3 m from the observation chamber and the lens was focused in a plane at the center such that the field of view was 4 cm2. The container was uniformly illuminated from above with one 20-watt fluorescent light providing 1,900 lumens of light. 

Two separate experimental series were completed: the first one focused on three larval fish ages (1, 3, and 10 dph), and offered a single prey type per experiment (nauplii, copepodites or adults). The second one recorded predatory-prey interactions for larval ages 1 to 14 dph and mixed prey fields (nauplii + copepodites + adults). Capture success was determined from video recordings of predatory interactions between larval clownfish and three developmental stage groups of the copepod Parvocalanus crassirostris.

For the data analysis, videos were reviewed, larval predatory strikes identified and scored as to outcome (successful/unsuccessful).  In a second analysis for experiment II, predatory strikes were scored for the targeted prey type to determine selectivity.  For approximately 15% of strikes, resolution, clarity or contrast was insufficient to accurately determine prey type and these were excluded from the final dataset.

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions

Description from NSF award abstract:
This study will experimentally elucidate the dynamics of predator evasion by different species and life stages of copepod responding to a model larval fish predator. The PIs will use standard and high-speed videographic and cutting-edge holographic techniques. Predator-prey interactions within planktonic communities are key to understanding how energy is transferred within complex marine food webs. Of particular interest are those between the highly numerous copepods and one of their more important predators, the ichthyoplankton (the planktonic larval stages of fishes). The larvae of most fishes are planktivorous and heavily dependent on copepods for food. In general, evasion success increases with age in copepods and decreases with the age of the fish predator. How this plays out in detail is critical in determining predatory attack outcomes and the effect these have on predator and prey survival. To address this problem, different copepod developmental stages will be tested against several levels of predator competence, and the results examined for: 1) the success or failure of attacks for different combinations of predator and prey age class; 2) the kinematics (reaction latencies and trajectory orientation) for escape attempts, successful and unsuccessful, for different age classes of copepod; 3) the hydrodynamic cues generated by different ages and attack strategies of the predator and the sensitivity of different prey stages to these cues; and 4) the success or failure of the predatory approach and attack strategies at each prey stage. The data obtained will be used to inform key issues of zooplankton population dynamics. For the prey these include: predator-evasion capabilities and importance of detection ability, reaction speed, escape speed, escape orientation, and trajectory irregularity; for the predator they are: capabilities and importance of mouth gape size, stealthiness, hydrodynamic disturbance production, and lunge kinematics.