Restoration Project

MBC Aquatic - Hope Ranch

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

23rd Sep 1991 – 7th 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:

At Hope Ranch 19 weeks after deployment, of the 89 mushroom anchors (with transplants) observed, 4 (5%) were inverted. Transplants were observed on 77 (87%) of the anchors. Nearly all transplants had fronds >1m in length (average number of fronds >1m per plant was 6). The average holdfast diameter was 29 cm.

Key Reasons For Decline:

Heatwave

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

0.019
/ m2
0
/ m2
Costings:
Cost Currency:USD
Total Cost:2,580

Observation Date

23rd Sep 1991 – 22nd Oct 1991

Action Summary:

Mushroom anchors were installed at sites. Mushroom anchors consisted of semi-hemispherical concrete blocks (diameter= 40 cm, height= 15 cm) which were used as artificial growth centres. The flat, upper surface provided substrate for natural Macrocystis recruitment, while the rounded bottom was partially buried in the sediment to secure the structure in place. These were deployed in sandy areas where adult Macrocystis were present so that kelp spores were available for recruitment to the anchors. 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. Recruitment unknown as surveys were conducted 3-4 weeks post deployment.

Project Outcomes:

Of the 249 mushroom anchors (without transplants) observed at Hope Ranch, 12 (5%) were inverted. No kelp recruitment was observed, but this was expected at 3-4 weeks post deployment.

Key Reasons For Decline:

Heatwave

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

0.003
/ m2
0
/ m2
Costings:
Cost Currency:USD
Total Cost:1,700