Dataset: crab nocturnal surveys

Name: Day vs. night Calcinus hermit crab abundance on Millepora coral from Virgin Islands National Park in the Great Lameshure Bay, St. John, US Virgin Island from 2010-2011 (St. John LTREB project)
Published: 2014-08-15
Keywords: oceans

Cite This Dataset

Spatial Extent: N:18.3182 E:-64.7228 S:18.3116 W:-64.7242

Temporal Extent: 2010 - 2011

Project:

LTREB Long-term coral reef community dynamics in St. John, USVI: 1987-2019 (St. John LTREB)

Principal Investigator:

Peter J. Edmunds (California State University Northridge, CSUN)

Student:

Darren J Brown (California State University Northridge, CSUN)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

2014-08-15

Version Date:

2014-08-15

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Day vs. night Calcinus hermit crab abundance on Millepora coral from Virgin Islands National Park in the Great Lameshure Bay, St. John, US Virgin Island from 2010-2011 (St. John LTREB project)

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Description

The study was conducted in St. John within the Virgin Islands National Park (VINP). The majority of our analyses focused on the shallow fringing reefs of Great Lameshur Bay and was completed in 2010 and 2011. Surveys in July and August 2010 focused on the natural history of the association by evaluating Millepora spp. for colony size and population density of C. tibicen. Surveys were repeated between June 2011 and August 2011 and expanded to the north and east shores of St. John to test the generality of the observations initially made in 2010. In 2011, manipulative experiments were conducted to test the functional basis of the Millepora-Calcinus association and evaluate whether it could be described as a commensalism.

These data were published in Brown D, Edmunds PJ. (2013)

Original submitted excel file in data file section.

Methods & Sampling

Abundance of Calcinus tibicen on Millepora spp.: Surveys in 2010 were performed during the day at Tektite and Yawzi Point in Great Lameshur Bay. At each site, 25-m transects were placed parallel to the 2-6 m depth contour and Millepora spp. colonies within 1 m of either side of the transect were censused for size and abundance of C. tibicen. The benthos was also searched for C. tibicen to determine the extent to which they occurred on surfaces other than Millepora spp. Millepora spp. was scored for size and presence of C. tibicen. The sizes of C. tibicen were estimated indirectly through the sizes of the gastropod shells they occupy.

Nocturnal surveys: Surveys were completed at night in 2011 to test the possibility that C. tibicen leave Millepora spp. after dark. This portion of the study was motivated by the strong likelihood that C. tibicen is an omnivorous detritivore and, therefore, eventually would have to leave their Millepora spp. to forage. Presumably, this behavior might best be accomplished at night when they could escape visual fish predators.

Site fidelity: Hermit crabs were collected and grouped by the colony from which they were collected, and their Millepora spp. colonies marked so that tagged crabs could be returned to the same colony. Site fidelity was expressed as the percentage of tagged hermit crabs remaining on each colony over the census period. Results table.

Behavioral response: To evaluate the capacity for C. tibicen to find Millepora spp., two experiments were conducted. First, a displacement experiment was conducted in 2010 and 2011, in which C. tibicen were removed from Millepora spp. colonies during the day, placed on adjacent algal turf, and observed for 5 min to determine whether they returned to the same Millepora spp. Second, a laboratory experiment was conducted in 2011 in which C. tibicen were placed in a Y-maze and presented with a choice of Millepora spp. versus seawater.

Results of Y-Maze Choice:
Millepora: 29
Other: 14
Total: 4

Predator avoidance: To gain insight into the mechanistic basis of the Millepora- Calcinus association, a tethering experiment was conducted in which the losses of secured C. tibicen were determined on Millepora spp. versus sand/algal turf.

Data Files

File
day_night.csv (Comma Separated Values (.csv), 409 bytes) MD5:bb06db95dde3695341705a8c292347f0 Primary data file for dataset ID 523481
Millepora_Calcinus_Data_for_2012_CoralReefs_BCODMO filename: Millepora_Calcinus_Data%20_for_2012_CoralReefs_BCODMO.xls (Octet Stream, 240.00 KB) MD5:5165db393eb498d22f76fdb6916524ce Original excel file for dataset 523358, 523441, 523481, 523451. This file has been reworked and put into the BCO-DMO system for improved interoperability.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Environmental Biology	DEB-0343570
NSF Division of Environmental Biology	DEB-0841441

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
Edmunds_VINP		1987-01-01	Virgin Islands National Park	Peter J. Edmunds (Principal Investigator)	data info

Instruments

None available yet

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
site	location of the Millepora colony	unitless	site
lat	latitude; north is positive	decimal degrees	lat
lon	longitude; east is positive	decimal degrees	lon
colony	colony id number: running count of colonies sampled	unitless	sample
count_5pm	the total number of crabs found on each Millepora colony at 5pm	individuals	count
count_10pm	the total number of crabs found on the same Millepora colonies at 10pm	individuals	count

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Database

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Dataset: crab nocturnal surveys