Restoration Project

MBC Applied Aquatic - South Scotchmans Cove

Restoration Objective:

The aim of restoration was to reseed kelps where they had exhibited little or no recovery in order to improve biological and commercial outcomes.

Site Selection Criteria:

Transplant sites were selected where giant kelp was once present. Ideal transplant sites had many attachment points, no competing macroalgae and were in less than 13m of water.

Cause Of Decline:

Historically, beds of giant kelp (Macrocystis pyrifera) along the Orange County coastline were dense and covered much of the available rocky substrate from the shallow subtidal area down to 20m and deeper. These beds supported a diverse assortment of fish, invertebrates, and other plants, many of which were of significant interest to commercial and sport fisherman. The warm waters brought by the El Niño of 1982-1983 caused the loss of most giant kelp stands leaving only a few surviving patches along the Orange County shoreline. Additional stressors to kelp populations included urbanisation, low water quality, storms and overfishing.

Key Reasons For Decline:

Heatwave

Scientific Paper

Orange County Kelp Restoration Project

M.B.C.Applied Environmental Sciences, , p.93.

Organisation:

MBC Aquatic

Site Observations:

Observation Date

30th Jan 1987 – 27th Sep 1989

Action Summary:

Adult and juvenile Macrocystis pyrifera plants were transported from the donor site quickly, covered in a tarp and kept cool and moist. Juveniles were also grown in lab culture. Kelps were attached using rope sewn through the holdfast with needles. Adult and juvenile kelps were transplanted to 12 sites. Sites were monitored, maintained, and sometimes expanded with additional juvenile kelps over three years.

Lessons Learned:

Grazing by herbivorous fish and sea urchins inhibited kelp recruitment.

Project Outcomes:

During a final inspection dive in September 1989 in the South Scotchmans Cove site, there were no adults present but 278 subadult and 44 juvenile kelp plants. In approximately 75% of the site, 50% of subadults had moderate to severe grazing damage.

Nature of Disturbance:

Herbivorous fish (including opaleye and halfmoon) grazed 90% of initial transplants down to their holdfasts.

Key Reasons For Decline:

Heatwave

Area of Restoration (In Square Metres)

78,292.5

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Count

3221618
Costings:
Cost Currency:USD