California Department of Fish and Wildlife - Malibu Beach

Restoration Project

California Department of Fish and Wildlife - Malibu Beach

Restoration Objective:

The aims of this study were to determine: (i) the practicality of man-made reefs in southern California waters, (ii) the best materials to use, and (iii) the return to the fishermen. The overall objective was to test methods of generating kelp forests to enhance fisheries harvests.

Site Selection Criteria:

Reef sites were selected in extensive flat sand or mud-sand areas far away from rocks that might provide 'competition' to the artificial reefs.

Cause Of Decline:

Macrocystis pyrifera beds along the southern California coast were relatively stable prior to 1940. Declines were first reported in 1945 in areas nearest major sewage outfalls. This deterioration progressively affected beds at increasing distances from the outfalls, leaving small patches. Deterioration of kelp accelerated when an influx of warm oceanic water persisted off California from 1957-1959.

Key Reasons For Decline:

Multiple

Scientific Paper

Man-made reef ecology (Vol. 146). State of California, Department of Fish and Game.

C.H. Turner, E.E. Ebert, R.R. Given
https://escholarship.org/uc/item/2s55m47r

Organisation:

California Department of Fish and Wildlife

Site Observations:

Observation Date

1st Aug 1960 – 1st Nov 1963

Action Summary:

An artificial reef was constructed from 333 tons of class B quarry rock, one streetcar, 14 automobile bodies, and 44 concrete shelters, each of the materials making up a similar total cubic area. Each of the four materials formed a corner of each reef, and was placed 100 - 200 feet from its nearest neighbour to allow separate fish populations to build up around each material.

Lessons Learned:

Transplants were on an artificial reef, did not last long.

Project Outcomes:

Giant kelp became established naturally only on the Paradise Cove car body reef, presumably due to this reef's proximity to an existing kelp bed.
Coastal ecosystems are threatened by increasing population sizes, urbanisation, water pollution and harvesting pressures.

Key Reasons For Decline:

Multiple

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Presence / Absence of Kelp

Costings:
Cost Year:1960
Cost Currency:USD
Total Cost:6,000
Capital Cost:6,000

Observation Date

1st Feb 1961 – 1st Jul 1961

Action Summary:

In February 1961, mature Macrocystis plants were transplanted from the Paradise Cove reef to the Malibu reef concrete shelters. These plants, collected in 40- and 50-foot depths and protected from grazers by net sacks and wire cages, ranged from 3 to over 75 feet long.

Lessons Learned:

Transplants were on an artificial reef, did not last long.

Project Outcomes:

Malibu Beach transplants survived a few weeks until adverse oceanographic conditions (warm turbid waters) resulted in their demise.

Nature of Disturbance:

All Malibu Beach kelps died after July, apparently due to warming waters.

Key Reasons For Decline:

Multiple

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Presence / Absence of Kelp

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