Dataset: Predation Rate By Sea Stars on Mussels

PREDATION RATE - OREGON
PISCO Intertidal
Location: Oregon and California rocky intertidal

Oregon State University

Project Duration May 2017 - 2020

Purpose:   The purpose of this experiment is to study the rate of predation on mussels in the low intertidal.

Number of sites: 7 (Fogarty Creek, Boiler Bay, Yachats Beach, Strawberry Hill, Cape Blanco**, Port Orford Heads, Rocky Point) **at CB full cage reps double as annual Mussel Growth

Annual experiment schedule:          April: Project is restarted, new mussels are deployed

                                                            May: Vexar plots are domed

                                                            June: Vexar removed and cages are installed

                                                            June-March: Monitoring plots

Number of replications per site: 5

Number of treatments per replicate: 2  (Fence Control, Cage)

Installation Supplies:    

• Black vexar mesh,
• Plastic washers,
• Stainless lag screws,
• Plastic anchors,
• Stainless steel mesh cages and fences,

Monitoring Supplies

• Datasheet,
• Pencil,
• Oil pastels

Setup in Field:

Collect 500 mussels from the midzone at each site on the day of deployment. Mussels should be about 5-6cm long.

Clear any mussels and organisms remaining from the past year in the plots. The mussels transplanted to the cleared plots and secured to the rocks using Vexar mesh. Dome the vexar mesh over the mussels, giving the mussels 1-2 inches of space between them and the mesh. Doming can be done after 2 weeks to a month after initial deployment to promote byssal thread attachment. 

Remove the vexar from the plots a month after it has been domed. Once the Vexar is removed from each plot, install the stainless steel cages and fences around the mussels. Add colored zipties to the Cages and Control Fences to distinguish between each replicate number (Red =1, Orange =2, Yellow =3, Green =4, Blue =5).

Monitoring:

Pred Rate is monitored at each visit, or as often as possible. Count mussels within each treatment and record the number of alive and dead individuals. Use oil pastels to mark the individuals counted within each fence and cage to keep track of which have been counted and which have not.

In June, July, and August the number of sea stars within a 1 meter radius around each plot is counted and recorded in the notes section of the datasheet. Some sea stars will be double counted if treatments are close together, this is normal and will not affect analysis.

Pisaster and Nucella spp. should be removed from the cage plots, but not recorded. The monitoring of Pred Rate at a site will be terminated when the mussels from all fence plots are gone.

 

Instruments:

Rock Hammer Drill: Amazon – Bosch – 11536VSR

https://www.amazon.com/Factory-Reconditioned-Bosch-11536VSR-RT-Lithium-Ion-SDS-Plus/dp/B000PDFXAO/ref=sr_1_1?ie=UTF8&qid=1520283121&sr=8-1&keywords=Bosch+11536VSR

Lags and anchors: McMaster Carr

https://www.mcmaster.com/#stainless-steel-lag-screws/=1br8j6w – item number 92351A558

Polyethylene Conical Screw Anchor, No. 14-16 item number: 97068A140

Mesh, Plastic “Vexar”: Memphis Net and Twine     http://www.memphisnet.net/  (888)674-7638

Black: 1/4 or ½ in. Mesh, Wind and Sand Fence, Standard  Product ID: PN3