Table of Contents

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

Data for predation of two snail species (Cerithideopis californica and Cerithideopsis montagnei) by a species of whelk (Thais kiosquiformis) at different levels of potential escape structure.  Three types of cage treatments were used which varied the amount of structure.  

1. Trunk: cages included mangrove trunks.
2. Trunk_Pneum: cages included both mangrove trunks and pneumatophore roots.
3. Unstructured: cages did not include mangrove trunks or pneumatophore roots.

To determine whether differential use of mangrove structure by snail species mitigates predation rates by the whelk Thais kiosquiformis, we conducted a field experiment. We used T. kiosquiformis because it was the only predator we observed eating Cerithideopsis californica and Cerithideopsis montagnei snails (both according to direct observation and forensic evidence) during preliminary tethering trials in the forest.

Cages were constructed using an outer shell of welded stainless steel wire 1/2” mesh to ensure rigidity and an inner lining of chicken wire with smaller (1/4”) mesh size to prevent snail escape and prevent predator invasion. We built circular cages that enclosed 0.5 m2 and were 40 cm high. Cage height was reduced by no more than 5 cm when buried and cages had no lids because in lab trials, snails did not climb the metal cage materials.

Six cages were assigned to each of six treatments (36 cages total) that crossed predator presence/absence with three types of structure availability. The three structural manipulations were mangrove tree trunk only, both a trunk and pneumatophore roots, or no climbing structure. We used naturally existing tree trunks for these treatments, requiring haphazard but non-random cage placement. The appropriate root treatments were sometimes created by pruning preexisting pneumatophores to eliminate them. Each cage was cleared of all macrofauna and stocked with 50 snails of each Cerithideopsis species and, if appropriate, five predatory T. kiosquiformis whelks. All snails were collected on-site, within 50 m of where cages were installed. Cages were monitored as often as the tide and weather permitted; almost daily.

Over the course of the experiment, we documented T. kiosquiformis and Cerithideopsis spp. climbing behavior and all T. kiosquiformis predation events (recorded in the dataset accessible on this webpage) that occurred inside each cage. We did not count or record the number of uneaten prey snails, but all prey snails in a cage not recorded as eaten were assumed to be alive. Over time, a number of cages developed gaps through which both predator and prey snails could escape as the tide redistributed shell rubble in and around the cages. We stopped collecting data on a cage after a gap was seen since the number of predator and prey snails inside the compromised cage was no longer guaranteed to be equal to that in other cages.

DMO notes:
spelled out the name of the prey species;  was reported with abbreviation;
added lat and lon to dataset to enable geospatial referencing

Extracted from the NSF award abstract:

This proposal aims to catalyze a research collaboration between professor Byers from the University of Georgia, professor Torchin from the Smithsonian Tropical Research Institute and Professor Lopez from the Institute for Scientific Research and Technological Services (INDICASAT) in Panama. The addition of Professor Lopez to this collaboration adds expertise in plant biology and mangrove forest structure to the proposed project and gives a new direction to the existing collaboration between Drs. Torchin and Byers. This project will examine the effects of parasitism and predation of a group of congeneric mud snails of the genus Cerithidea in tropical mangroves. These preliminary experiments would be carried out during one summer to gather preliminary data for the submission on an NSF proposal in the future.