Restoration Project

MBC Applied Aquatic - Gaviota

Restoration Objective:

Kelp beds are extremely important habitats, providing space, shelter, and forage for many invertebrates and fish. The decline of the kelp beds along the coast of Santa Barbara after the 1983-1983 El Niño event severely reduced the productivity and biological diversity of the local nearshore environment. In an on-going effort to re-establish the productivity and marine resources of the region, CDFG contracted Kelco in 1991 to continue restoration work in Santa Barbara County.

Site Selection Criteria:

Sites were selected where: there was a previous history of kelp, water depth was less than 16m, no purple urchins were present and adult Macrocystis were in close proximity.

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

1991 Santa Barbara Kelp Restoration Project

M.B.C.Applied Environmental Sciences, .

Organisation:

MBC Aquatic

Site Observations:

Observation Date

10th Jun 1991 – 24th Oct 1991

Action Summary:

"Staples" (60 cm long staple-shaped rebar with barbed ends) were driven through Macrocystis holdfasts to secure loosely attached naturally occurring plants. Nylon line, strung between the two prongs of the staple approximately 8 cm below the top, helped secure the plants in place.

Lessons Learned:

Sites were selected where: there was a previous history of kelp, water depth was less than 16m, no purple urchins were present and adult Macrocystis were in close proximity. Stapled plants were similar in growth to natural recruits.

Project Outcomes:

At Gaviota 2 in November 1991, 182 stapled plants were observed and all appeared healthy. Adult plants had an average of 28 fronds > 1 m in length, and an average holdfast diameter of 62 cm. A total of 118 non-stapled naturally-occurring plants were also observed. Unstapled plants were similar in size and appearance to the stapled transplants. Both natural and stapled plants reached the surface during November and produced a thin canopy when currents were slack.

Key Reasons For Decline:

Heatwave

Area of Restoration (In Square Metres)

56,660

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

0.019
/ m2
0
/ m2
Costings:
Cost Currency:USD
Total Cost:1,724

Observation Date

15th Jun 1991 – 8th Nov 1991

Action Summary:

Mushroom anchors with Macrocystis pyrifera transplants were installed at sites. Mushroom anchors consisted of semi-hemispherical concrete blocks (diameter= 40 cm, height= 15 cm), to which Macrocystis plants (0.5 to 1 m in length), from cultured or natural populations were attached. The anchor was then deployed from a slow moving vessel.

Lessons Learned:

Sites were selected where: there was a previous history of kelp, water depth was less than 16m, no purple urchins were present and adult Macrocystis were in close proximity. Mushroom anchors with transplants were successful.

Project Outcomes:

19 weeks after deployment at Gaviota 1, of 109 MATs observed, only 3 were inverted. Minor amounts of scouring was seen around the base and sides of some anchors. Kelp transplants were observed on 94 (86%) of the MATs. Most plants appeared healthy and showed very little grazing damage. All transplants had fronds > 1 m in length (average number of fronds per plant = 6) and average holdfast diameter was 33 cm. Several transplants had large bundles (> 1 m) of drift Desmarestia entangled amongst the fronds and at the bases near the anchor. After drift kelp removal, it was noted that the areas of the Macrocystis that had been in contact with the Desmarestia were pale and had tissue damage.

Key Reasons For Decline:

Heatwave

Area of Restoration (In Square Metres)

45,000

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

0.021
/ m2
0
/ m2
Costings:
Cost Currency:USD
Total Cost:2,874