Restoration Project

California Department of Fish and Wildlife - Paradise Cove

Restoration Objective:

This experiment was conducted to assess the true value of artificial reefs, which are installed to improve the abundance of sportfish and thereby improve fishing opportunities.

Site Selection Criteria:

Artificial reef sites were selected in flat, sandy areas where fishing for sport fishes such as kelp bass, sand bass, and sheephead was generally poor. Reef sites were chosen between 50 and 60 feet, as these depths were considered suitable for the target fish species and within the optimum range for giant kelp plants which would further enhance the value of artificial habitat.

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

Artificial habitat in the marine environment. Resources Agency of California, Departament of Fish and Game

J.G. Carlisle, C.H. Turner, E.E. Ebert, .https://escholarship.org/uc/item/99n3p098

Organisation:

California Department of Fish and Wildlife

Site Observations:

Observation Date

26th May 1958 – 1st Nov 1960

Action Summary:

An artificial reef of 20 old car bodies was placed in 50 feet of water at Paradise Cove, near Malibu. SCUBA was used to measure presence of fish species and the giant kelp Macrocystis pyrifera before and after artificial reef installation.

Lessons Learned:

This study evaluates the true value of artificial reefs by measuring if artificial reefs can attract algae and kelp growth. It also evaluates how offshore oil drilling instillations affect these reefs.

Project Outcomes:

In October, 3 months after the artificial reef was installed, the first naturally seeded young M. pyrifera plants were observed. Numerous ¼- to 4½-inch tall plants were observed early in November. By December there were as many as 22 plants per square foot. Some had grown to over 2 feet by the end of January 1959 and many were 6 - 8 feet tall by late March. In April, fruiting fronds appeared on many plants over 4 feet tall. At this time, on each car there were 25-35 2-foot tall plants and 10-15 plants exceeding 10 feet, with the largest growing to 14 feet. Growth rate slowed after the tallest plants reached 40 feet. By November growth had resumed, and kelp had reached the surface and was about 50 feet long. The number of stipes varied from 3 to 25 per plant. In late February, some plants were 70 - 75 feet long and formed a considerable surface canopy.

Nature of Disturbance:

In July with the advent of warm water, black rot and loss of blades was observed.

Key Reasons For Decline:

Multiple

Area of Restoration (In Square Metres)

31.9

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Count

300
Costings:
Cost Year:1958
Cost Currency:USD
Total Cost:300
Capital Cost:300