Marine Sanctuaries Conservation Series MSD-04-3

U.S. Department of Commerce April 2004

National Oceanic and Atmospheric Administration

National Ocean Service

Office of Ocean and Coastal Resource Management

Marine Sanctuaries Division

 Sebastes chrysomelas, black-and-yellow rockfish

A Review of the Ecological Effectiveness of Subtidal Marine

Reserves in Central California

Part II:

Summary of Existing Marine Reserves in Central California and

their Potential Benefits
About the Marine Sanctuaries Conservation Series

The National Oceanic and Atmospheric Administration’s Marine Sanctuary Division (MSD)

administers the National Marine Sanctuary Program. Its mission is to identify, designate,

protect and manage the ecological, recreational, research, educational, historical, and aesthetic

resources and qualities of nationally significant coastal and marine areas. The existing marine

sanctuaries differ widely in their natural and historical resources and include nearshore and

open ocean areas ranging in size from less than one to over 5,000 square miles. Protected

habitats include rocky coasts, kelp forests, coral reefs, sea grass beds, estuarine habitats, hard

and soft bottom habitats, segments of whale migration routes, and shipwrecks.

Because of considerable differences in settings, resources, and threats, each marine sanctuary

has a tailored management plan. Conservation, education, research, monitoring and

enforcement programs vary accordingly. The integration of these programs is fundamental to

marine protected area management. The Marine Sanctuaries Conservation Series reflects and

supports this integration by providing a forum for publication and discussion of the complex

issues currently facing the National Marine Sanctuary Program. Topics of published reports

vary substantially and may include descriptions of educational programs, discussions on

resource management issues, and results of scientific research and monitoring projects. The

series will facilitate integration of natural sciences, socioeconomic and cultural sciences,

education, and policy development to accomplish the diverse needs of NOAA’s resource

protection mandate.
A Review of the Ecological Effectiveness of Subtidal Marine

Reserves in Central California

Part II:

Summary of Existing Marine Reserves in Central California and their

Potential Benefits

Richard M. Starr1, Mark H. Carr2, Jennifer Caselle3, James A. Estes4,

Craig Syms2, David A. VenTresca5, Mary M. Yoklavich6

1

 University of California Sea Grant Extension Program

2

 University of California Santa Cruz

3

 University of California Santa Barbara

4

 U.S. Geological Survey

5

 California Department of Fish and Game

6

 National Marine Fisheries Service

April 2004

 

Silver Spring, Maryland

April 2004

U.S. Department of Commerce

Donald L. Evans, Secretary

National Oceanic and Atmospheric Administration

VADM Conrad C. Lautenbacher, Jr. (USN-ret.)

Under Secretary of Commerce for Oceans and Atmosphere

National Ocean Service

Richard W. Spinrad, Ph.D., Assistant Administrator

Marine Sanctuaries Division

Daniel J. Basta, Director
DISCLAIMER

Report content does not necessarily reflect the views and policies of the National Marine

Sanctuary Program or the National Oceanic and Atmospheric Administration, nor does the

mention of trade names or commercial products constitute endorsement or recommendation for

use.

REPORT AVAILABILITY

Electronic copies of this report may be downloaded from the National Marine Sanctuaries

Program web site at www.sanctuaries.nos.noaa.gov. Hard copies may be available from the

following address:

National Oceanic and Atmospheric Administration

Marine Sanctuaries Division

SSMC 4, N/ORM62

1305 East-West Highway

Silver Spring, MD 20910

COVER PHOTO CREDITS

Sebastes chrysomelas, black-and-yellow rockfish: Daniel W. Gotshall

SUGGESTED CITATION

Starr, R. M., M. H. Carr, J. Caselle, J. A. Estes, C. Syms, D. A. VenTresca, and M. M. Yoklavich.

2004 A Review of the Ecological Effectiveness of Subtidal Marine Reserves in Central California,

Part II: Summary of Existing Marine Reserves in Central California and their Potential Benefits.

Marine Sanctuaries Conservation Series MSD-04-03. U.S. Department of Commerce, National

Oceanic and Atmospheric Administration, Marine Sanctuaries Division, Silver Sprin
CONTENTS

Introduction................................................................................................. 1

1) How do marine reserves conserve biodiversity and habitat? .................................... 3

1a) Do the existing marine reserves in Central California protect depleted,

threatened, rare, or endangered species? ........................................................ 3

1b) Do the existing marine reserves in Central California protect

representative habitats and species? ............................................................ 4

1c) What are the other potential ecological functions of reserves in Central California? .... 4

1d) What is the evidence that reserves in Central California actually conserve

biodiversity? ...................................................................................... 5

1e) How much area is needed to adequately protect Central California

species and habitats? ............................................................................. 6

2) How can reserves improve fishery management? .................................................. 7

2a) Do the reserves in Central California control fishery exploitation rates?.................... 7

2b) Do the reserves in Central California protect critical stages in the life

history of a species?............................................................................... 8

2c) Do the reserves in Central California reduce secondary fishing impacts?................... 9

2d) Do the reserves in Central California ensure against possible failures

of conventional regulatory systems?............................................................. 9

2e) Do the reserves in Central California conserve life history traits and genetic diversity? 10

3) Do the reserves in Central California increase scientific knowledge?.......................... 10

4) Do the reserves in Central California increase educational opportunities?...................... 11

5) Do the reserves in Central California increase recreational opportunities and tourism?...... 11

6) Do the reserves in Central California provide sustainable environmental benefits?........... 11

7) Do the reserves in Central California provide protection of cultural heritage?................. 11

Summary.................................................................................................... 12

Acknowledgements........................................................................................ 13
1

Introduction

In Central California, and elsewhere around the world, a great deal of discussion is

occurring about the use of marine protected areas (MPAs) as a tool to help manage marine

resources. This discussion is taking place because there is growing evidence that humans have

depleted marine resources in many parts of the world, often despite strong regulatory efforts.

Moreover, there is also mounting evidence that the degradation of marine resources began long

ago, and we do not fully realize how much humans have altered “natural” environments. This

uncertainty has led people to discuss the use of MPAs as a precautionary tool to prevent

depletion or extinction of marine resources, and as a means of redressing past damages.

The discussion about the use of marine reserves is increasing in intensity in California

because several resource management agencies are considering reserves as they create or revise

management plans. Often, the discussions surrounding this important public policy debate lead

to questions about the biological or ecological value of existing marine protected areas. More

than 100 MPAs exist along the coast of California. Many of these were established arbitrarily

and lack specific purposes. Some California marine protected areas also have co-occurring or

overlapping boundaries, have conflicting designations for use, and have conflicting rules and

regulations. Because few of the existing marine protected areas have clearly articulated goals or

objectives, however, it is difficult or impossible to evaluate their ecological effectiveness.

Marine reserves, often referred to as no-take MPAs, are defined as areas within which

human activities that can result in the removal or alteration of biotic and abiotic components of

an ecosystem are prohibited or greatly restricted. Usually, marine reserves are established to

conserve biodiversity or enhance nearby fishery resources. Thus, goals and objectives of marine

reserves can be inferred, even if they are not specifically articulated at the time of reserve

formation. The National Research Council published a report in 2001 that identified seven

potential goals for marine reserves. The report suggested that marine reserves could improve:

1) Conservation of biodiversity and habitat,

2) Fishery management,

3) Scientific knowledge,

4) Educational opportunities,

5) Enhancement of recreational activities and tourism,

6) Sustainable environmental benefits, and

7) Protection of cultural heritage.

We evaluated the ecological effectiveness of subtidal marine reserves in Central California

by comparing existing information with the predicted benefits of the goals listed by the National

Research Council. We reviewed information from the three marine reserves in the Monterey

Bay National Marine Sanctuary (Fig. 1: Hopkins Marine Life Refuge with about 32 ha of

protected area established in 1984; Point Lobos Ecological Reserve with about 280 ha of

protected area established in 1973; Big Creek Ecological Reserve with about 378 of protected

area established in 1994), and the one marine reserve in the Channel Islands National Marine

Sanctuary (about 12 ha of Natural Area protected in 1978 on the north side of East Anacapa

Island) in Southern California.
 2 

b

a

c

d

Monterey Bay National Marine Sanctuary

123°W

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Lovers Point

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10 m contour intervals

Hopkins Marine Life Refuge

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Point Lobos Ecological Reserve

Gamboa Point

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Big Creek 

Ecological Reserve

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natural area

Brown Pelican 

fledging area

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Anacapa Island

Ecological Reserve

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National Marine Sanctuary

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 ̄

Chad King

SIMoN

0 30 60 15

km

c

Figure 1. Four subtidal marine reserves, located in the Monterey Bay and Channel Islands 

National Marine Sanctuaries, reviewed for their ecological effectiveness: 

Hopkins Marine Life Refuge, Point Lobos Ecological Reserve, Big Creek 

Ecological Reserve, and the natural area on the north side of East Anacapa 

Island. 
3

We also reviewed studies of marine reserves in other temperate and tropical ecosystems to

determine if there are lessons to be learned about the effectiveness of marine reserves from other

parts of the world. After reviewing the available literature, we provided our best estimates of

what conservation or fishery benefits could be expected from existing reserves in Central

California. A more detailed discussion of the scientific studies that have been conducted on

marine reserves in Central California can be found in the companion document to this summary

(see: A Review of the Ecological Effectiveness of Subtidal Marine Reserves in Central

California. Part I: Synopsis of Scientific Investigations).

The purpose of this review is to provide information for the public policy debate, not to

advocate or oppose the formation of marine reserves. As a way of reporting the results of our

review, we present answers to frequently asked questions about the potential benefits of marine

reserves in Central California. It is very important to note that we were asked to focus on

biological parameters. Although we included a summary overview of socioeconomic concerns,

relatively little research has been done on this topic in Central California reserves. Any public

policy decision about the use of marine reserves also must include an analysis of how people

interact with, and are affected by, marine reserves.

1) How do marine reserves conserve biodiversity and habitat?

Marine reserves set up to conserve biodiversity and habitat are established either to 1)

protect depleted, threatened, rare, or endangered species or habitats, or 2) conserve representative

habitats and species. In the first case, the primary purpose of the reserve (or reserve system) may

be to provide extra protection for a species or habitat whose abundance is well below normal

levels or is declining at rates higher than that expected of natural variations. In the second case,

the primary purpose of a system of reserves is to conserve all species or biological processes in

representative habitats or portions of ecosystems.

Scientists and resource managers can use marine reserves to compare habitats and biological

communities in relatively undisturbed areas with those that are affected by human activities.

Protecting representative habitats from direct human alteration provides a good benchmark with

which to determine if observed changes are caused by human activity or environmental change.

Marine reserves established to conserve biodiversity also serve to protect a wide variety of

species, some of which may have been affected by human activities without our knowing it. An

additional benefit of a system of marine reserves designed to protect representative habitats and

species is that it can facilitate ecosystem recovery after either natural catastrophes (e.g., severe El

Niño events), or human-induced catastrophes, such as oil spills.

1a) Do the existing marine reserves in Central California protect depleted, threatened,

rare, or endangered species?

Some of the researchers studying the three marine reserves in the Monterey Bay National

Marine Sanctuary identified modestly increased size and abundance of various species exploited

in commercial and recreational fisheries. These studies also noted the presence of lingcod and

several rockfish species (e.g., bocaccio, yelloweye, canary, darkblotched) that have officially

been declared as overfished by the Pacific Fishery Management Council or are species of
4

concern identified by the California Department of Fish and Game. Because the area of

protection inside existing reserves is very small, however, the number of fish inhabiting existing

reserves is small compared to the total population size of the species of concern. Thus, existing

reserves protect a small number of individuals of overfished species, but are not large enough to

provide protection for a significant portion of the entire population of these species.

Red abalone, an overharvested species, have been observed in several of the reserves in

Central California. A few officially protected bird and mammal species occur in Central

California, but existing reserves are far too small to provide these species with meaningful

benefits. Although not officially part of the Anacapa Island Ecological Reserve in the Channel

Islands in Southern California, a small area on the north side of West Anacapa Island protects a

fledgling area for the endangered brown pelican.

No rare habitats have been identified in the existing marine reserves. Although some

overfished or endangered species have been observed, the existing studies were not designed to

locate rare species temporarily residing in marine reserves, thus more may use Central California

reserves. Additionally, existing reserves may harbor species whose populations are low, but

have not received protected status because so little is known about them; this includes most of

the nearshore species that are harvested without any assessment of population size and structure.

1b) Do the existing marine reserves in Central California protect representative habitats

and species?

The existing reserves in Central California all contain a variety of habitats and species that

are typical of temperate nearshore sand, rocky reef, and kelp forest habitats. Bottom types

observed in the existing reserves include sediment and shell substrates and a variety of rock

substrates, ranging from low relief rock shelves to high relief boulders and pinnacles. Small

algae and a variety of kelp species commonly cover the rocky habitats. Habitats and species

within the reserves closely match those found in adjacent areas. Thus, the existing reserves

contain habitats that are representative of shallow-water habitats in Central California. The fish

species inhabiting Central California reserves have been well documented; they are primarily

rockfishes, flatfishes, perches, gobies, and cottids. Invertebrate and algal species are not as well

documented, but appear to be similar to areas outside the reserves. Although existing reserves

contain representative habitats and species, they are too small to provide protection for a

significant proportion of these habitats and species occurring in Central California.

1c) What are other potential ecological functions of reserves in Central California?

Field studies of ecological roles played by marine reserves in other parts of the world have

focused primarily on changes in species protected from fishing. Surprisingly few studies or

mathematical models have been developed to understand how the structures of entire biological

communities, and species interactions, change with reserve protection. The ecological process

that involves species interactions and community change is termed trophic cascades. The few

field and modeling studies that have attempted to evaluate trophic cascades involved the role of

predators on major grazers such as sea urchins and the resulting influence on the cover and

density of macroalgae. Based on these studies, and other scientific literature, there is sufficient
5

evidence to expect that marine reserves will experience different trophic cascades in different

regions within California. For example, in kelp forests in Southern California, protection of

lobsters and sheephead (that limit sea urchin populations) is predicted to increase kelp density

within reserves and thus species associated with kelp forests. In Central California, where sea

otters limit sea urchin populations, reserves will probably have little effect on urchin populations,

and thus no cascading effect on kelp forests is anticipated. Instead, any change in community

structure would likely result from changes in fish assemblages and in the invertebrates fed upon

by different species of fishes. In Northern California, where commercial fishing is the primary

control of sea urchin populations, species composition in kelp forest reserves may exhibit

fluctuations that are caused by natural variations in sea urchin abundance.

The literature describing trophic cascades, however, indicates that when ecosystems are

heavily degraded, the interactions between predators and prey may limit recovery of depleted

species. This implies that there is no guarantee that an area that was once rich in marine life, but

is now barren, will recover to its original state if protected inside a marine reserve. Simply

stated, we know that abundance and size of fished species will increase in marine reserves, but

we cannot fully predict what the trophic structure of the community will look like in the reserve.

Moreover, changes in community structure will occur over an unknown period of time. This

makes it difficult to use a fixed date in the future to determine if a marine reserve has

successfully recovered to a pre-harvest condition.

1d) What is the evidence that reserves in Central California actually conserve biodiversity?

Research that has been conducted in other parts of the world has shown that well designed

reserves contain higher species diversity, more abundant species, larger fish, and better habitat

than similar areas outside the reserve. These characteristics, termed reserve effects, have been

shown to accrue rapidly in tropical areas, but more slowly in temperate environments.

Reserve effects are apparent in Central California marine reserves. In two of the three

marine reserves in Central California (Pt. Lobos and Hopkins), fish abundance and size are

greater inside the reserves relative to adjacent areas with similar habitat, although differences are

modest. At the Anacapa Island Ecological Reserve in Southern California, the density of

harvested species is much greater than densities measured outside the reserve. The densities of

species that are not commonly harvested, however, are similar or greater outside the reserve.

Species composition, size composition, and abundances of fishes are similar inside and outside

the Big Creek Ecological Reserve. Given that this reserve has been in place less than a decade,

the fact that most fish species there are rockfishes, and that most rockfishes grow slowly and

experience only episodic successful recruitment, it is not surprising that marked differences have

not been observed inside versus outside the reserve. The lack of differences may also be due to

lower fishing pressure on that part of the coast, or movements of fishes using the reserve. More

years will need to pass before we would expect to see differences in fish abundance inside and

outside Big Creek Ecological Reserve.

Research conducted in Central California reserves has shown that fish abundance, size, and

species composition in reserves are directly related to type, size, and extent of habitats located in
6

the reserve. This indicates that the number and variety of habitat types and depth ranges

encompassed by reserves in Central California directly influences the effectiveness of existing

reserves for conserving biodiversity. The existing marine reserves are all located in shallow

water (less than 50–120 m deep). In that respect, it is clear that existing reserves in Central

California protect only those animals inhabiting shallow water habitats. If the goal of a marine

reserve system in Central California is to protect a large number of species (protect biodiversity)

at various life stages, then it is important to establish marine reserves that extend into deeper

water than those currently in existence. Similarly, if a goal is to increase the number of species

protected, then it is important to establish marine reserves that contain a mixture of habitats, but

especially high relief rocky habitats. High relief rocky habitats in Central California contain a

larger number of species than other habitats. From a practical standpoint, rocky habitats

probably require more protection, because many species inhabiting shallow soft bottom habitats

are already somewhat protected by limitations on the use of trawl and gillnet fishing gear in State

waters.

1e) How much area is needed to adequately protect Central California species and

habitats?

The size of a reserve needed to successfully protect populations and ecosystem processes is

currently unknown, but likely dependent upon a variety of factors such as the density, amount of

movement, reproductive capability, and larval dispersal distances of protected species. Other

factors, such as the location and shape of a reserve, the amount of pollution entering a reserve, or

the rate of poaching in a reserve, also influence the amount of area needed for a reserve to be

effective. Based on what we know about fish movements and larval dispersal of most species in

Central California, it is probable that existing marine reserves are too small to protect all but the

most sedentary species. Abalones, and other sedentary species with short larval dispersal

distances, are the most likely species to benefit from the existing reserves. Highly mobile

species, such as migratory fishes, birds, and mammals are less likely to benefit from reserves.

The specific amount of area recommended for inclusion in a reserve is usually dependent

upon the exact goals delineated; recommended sizes are usually smaller for conservation

reserves than those designed to enhance fisheries. For the sake of this review, assume that a

public policy goal is to help conserve or protect at least some amount of all the representative

species and habitats in Central California. In terms of the international discussions about the

amount of area needed to conserve biodiversity, scientists have recommended protecting a

minimum of 5% of a habitat area or species population size. The existing reserves in Central

California cover an area that is less than 0.3% of state waters in this region, and less than 0.1%

of the area in California’s national marine sanctuaries, although these numbers may be slightly

higher if you just measure shallow rocky habitats. This means that existing reserve area is 17–50

times smaller than the minimum amount of area suggested by international scientists for areas

comparable to California coastal waters and national marine sanctuaries, respectively. Thus,

existing marine reserves in Central California protect an area that is too small to achieve a goal

of conserving biodiversity or habitats in this region. The actual size needed to protect

biodiversity would depend upon specific conservation goals, other management actions outside

reserves, and the level of risk the public is willing to take.
7

2) How can reserves improve fishery management?

Reserves may be designed to meet a variety of fishery-related goals and objectives. For

example, marine reserves can help control fishery exploitation rates by directly protecting a

portion of the population from overfishing. Marine reserves may serve as controls for fishery

scientists to study biological processes in unfished populations, and this information is useful to

develop more accurate stock assessment models. Also, marine reserves may be used as a

precautionary tool to ameliorate the effects of recruitment overfishing. Recruitment overfishing

occurs when fishing pressure causes a fish stock to become too small to sustain its population

size through reproduction. Reserves reduce the impacts of recruitment overfishing by providing

a haven for larger fish (that carry more eggs than smaller fish) than would occur in fished areas.

This could be especially relevant to rockfish populations that have dramatically variable

recruitment success. Similarly, reserves may minimize the effects of growth overfishing.

Growth overfishing occurs when high fishing pressure greatly reduces the mean size of fish

caught. Reserves can minimize the effects of growth overfishing if some of the larger fish leave

the reserve and are caught in nearby fisheries. The export of fish from a reserve to adjacent

fisheries may thus increase fishery yield, as long as effort shifts and reduced fishable areas are

accounted for in fishery management. An important socioeconomic point to consider is that

reserves have the potential to redistribute fishing effort, and thus yield, a factor that must be

evaluated when reserves are established. Thus, the extent to which reserves affect yield is

dependent upon the design of the reserve network, how much fishing occurs outside the

protected area, and the extent to which the closed areas are matched with more conventional

approaches to controlling fishing effort. In this respect, it is important that a new marine reserve

be designed in conjunction with other fishery management actions outside the reserve.

2a) Do the reserves in Central California control fishery exploitation rates?

Existing reserves in Central California were not established with the goal of controlling

fishing effort, and are probably too small to be used effectively as controls to differentiate natural

changes in a population from changes caused by fishing. For species that are targets of

commercial or recreational fisheries, reserves in Central California do protect a portion of the

population from overfishing. As stated earlier, however, the size of the existing reserves is so

small that this benefit is probably negligible. Similarly, the abundance of fishes in existing

marine reserves is too small to effectively rebuild populations that have been overfished, because

current fishery models indicate that even if fishing were closed along the entire coast, it would

take 100 to 150 years to rebuild bocaccio and yelloweye rockfish populations, respectively, to

40% of their original population size.

Field studies of fishery benefits associated with reserves in other parts of the world have

primarily focused on the abundance and size of harvested species that are protected in a reserve.

There is a large body of evidence to show that numbers and sizes of heavily fished species

increase within marine reserves. A small number of studies in tropical ecosystems have

demonstrated transport from a reserve to fisheries immediately adjacent to the reserve, a process

termed “spillover”. Few studies have demonstrated spillover in temperate systems.
8

To date, no studies have directly examined spillover or increased yield from a reserve in

Central California, nor is much information available to evaluate fishing patterns near reserves.

Information on short-term movements of targeted species and how that relates to the size of

existing reserves is also lacking. Without such information it is very difficult to estimate rates of

spillover and contributions of existing reserves to yield of nearby fisheries. Improved knowledge

of fish distribution and movements, fish habitat use, and fishery responses to marine reserves

(e.g., effort shifts and catch rates) will be critical to predict or interpret spillover from a reserve.

A few models have been developed that describe the potential role of reserves in

contributing to fishery yields through their contribution to larval production, emigration, and

recruitment to fished populations outside reserves. Models developed to evaluate potential

benefits of spillover to a fishery indicate that emigration of adults out of reserves into fished

areas can lead to increases in yield per recruit, primarily when emigration rates are moderately

high and fishing mortality outside the reserve is high, but regulated. These models also indicate

that the contribution to increased yield is constrained to areas close to the reserve. Predictions of

how much reserves can increase yield vary widely. Some models suggest that a system of

reserves can provide comparable yields as those obtained through traditional effort control. In

these models, the effect of adding reserves on total yield is essentially the same as decreasing

fishing mortality.

Several models suggest that to enhance yields, the proportion of a stock necessary to be set

aside within reserves ranges from 20 to 70%, depending on stock size and distribution of fishing

effort. Many of these models indicate that reserve benefits are greater when stocks have been

overfished. Thus, any study measuring the relative effectiveness of a reserve will benefit greatly

from good estimates of fishing mortality. Because recent stock assessments indicate that several

California groundfish species are overfished (e.g., several rockfishes, lingcod), the existing

models suggest there is potential for marine reserves to help some fisheries in Central California.

There is general consensus, however, that marine reserves should not be established for fisheries

conservation purposes without careful consideration of corresponding fishery management

actions outside the reserve. One very important conclusion and implication from all of the above

models is that for reserves to effectively increase yield in fisheries, they would need to cover far

more area than the existing reserves, but not so much as to preclude fishing. Thus, before marine

reserves could serve to augment fisheries management, a public policy debate would need to take

place that discussed marine reserves in the context of all other fisheries management tools.

2b) Do the reserves in Central California protect critical stages in the life history of a

species?

Many marine reserves around the world have been established to protect spawning or

juvenile rearing grounds. Closing areas that are critical habitats for species is a very effective

way to improve conservation of a species. Conservation benefits accrue for four reasons. First,

fish on spawning grounds are often easier to catch, so protection of spawning areas reduces

fishing mortality. Second, because more adults are able to spawn, more offspring are produced.

Third, adults in reserves produce more offspring because larger adults often produce many more

eggs and larvae than smaller adults. Also, there is some evidence to suggest that offspring of
9

larger fish are more likely to survive than offspring of smaller fish. Fourth, if fishing practices

disturb habitat where adults aggregate to spawn, reserves protect the quality of these habitats.

There is no information to suggest that any of the reserves in Central California are

important spawning or rearing grounds for any species, except that market squid migrate to

spawn in parts of Hopkins Marine Reserve. Many of the species protected by marine reserves in

Central California do not migrate to spawn. Thus, existing reserves protect a small part of the

spawning population of many species. Existing reserves do protect important habitat, however,

for many rockfishes that settle in shallow water as juveniles, and migrate to deeper habitats as

they grow.

In the three older marine reserves (Pt. Lobos, Hopkins, and Anacapa Island in Southern

California), fish abundance, size, and species composition are greater inside the reserves relative

to adjacent areas. As a consequence, these older reserves in Central California have greater

potential larval production than nearby populations outside of reserves. Studies conducted a few

years after the Big Creek Ecological Reserve was established, however, showed little evidence of

enhanced fish production potential. Given the slow growth of most rockfishes, and the relatively

low fishing pressure in that area it is not surprising that marked differences were not observed

inside versus outside the Big Creek Ecological Reserve. The magnitude of the reserve effect on

increased potential of larval production appears to be directly related to the age of the reserve.

More years will need to pass before we would expect to see differences in larval potential inside

and outside Big Creek Ecological Reserve.

2c) Do the reserves in Central California reduce secondary fishing impacts?

Another potential role of marine reserves is to protect species and habitats from secondary

impacts of fishing such as habitat destruction and incidental catch of unwanted species (bycatch).

The protection of benthic habitats helps maintain biodiversity and may increase the production of

a species by increasing the carrying capacity of a critical habitat. The placement of reserves in

areas with historically high bycatch can reduce undesirable mortality of a species, providing

fishing effort is not simply increased and displaced to another area with high bycatch.

The existing reserves in Central California were not designed to reduce secondary impacts

of fishing. Many of the species harvested in Central California are rockfishes that have high

mortality rates when brought to the surface, however, so existing reserves have the potential to

reduce overall bycatch rates. The small area of existing marine reserves, however, indicates that

total benefits accruing from reduced discard rates are likely small.

2d) Do the reserves in Central California ensure against possible failures of conventional

regulatory systems?

Fishery managers often rely upon stock assessments to estimate allowable catch of a

species. Once the allowable catch is estimated, managers regulate catch with input (e.g., fishing

effort) or output controls (e.g., quotas). Often, stock assessments are inexact, quotas are difficult

to monitor before they are exceeded, fishing efficiency is greater than anticipated for a given

level of effort, and estimates of bycatch for use in fishery models are unreliable. The combined
10

uncertainty in fishing mortality and allowable catches can result in unexpected overfishing of a

species. This has occurred for several groundfish species on the U.S. West Coast. By removing

a portion of a fished population from exploitation, reserves can serve as a buffer or insurance

against unexpected overfishing, as long as fishing effort outside is controlled and reserves are

designed correctly. The small number of individuals protected by existing marine reserves,

however, combined with potential movements of fish out of marine reserves, indicates that

current reserves probably have little opportunity to ensure against possible failures of

conventional regulatory systems.

2e) Do the reserves in Central California conserve life-history traits and genetic diversity?

Many fishing methods lead to a reduction in mean sizes and ages of fish in a population.

This may in turn lead to a selection for slower growing fish and result in smaller size at maturity,

or changes in the sex ratio of a population. By protecting a portion of a population from fishing

pressure, reserves may help maintain or conserve the genetic diversity and a natural size and age

distribution on a population. The existing reserves in Central California protect a small number

of individuals of many heavily fished species. The small number of individuals protected,

combined with potential movement of fish out of marine reserves, indicates that existing marine

reserves probably have little opportunity to conserve life-history traits and genetic diversity in

populations of harvested species.

3) Do the reserves in Central California increase scientific knowledge?

Marine environments are very dynamic. Often, it is difficult to attribute observed changes

in an ecosystem to environmental change or to human alteration. Baseline studies that provide a

benchmark for evaluating future change are needed to differentiate natural variation from

anthropogenic change. A system of marine reserves may provide an opportunity to develop the

baseline information needed to differentiate between natural and human-induced change.

The few studies of existing marine reserves will serve as a baseline for evaluating future

changes. To date, however, little information exists on community-wide responses to protection

by reserves in Central California, and only one study has examined the status of fish populations

for more than two years. Moreover, the lack of sampling over the multiple years necessary to

test for trends in populations inside and outside reserves makes it difficult to determine causes

for observed differences. Thus, it is clear that ecosystem-wide responses have not been

examined and remain unknown, the temporal persistence of differences between reserve and

non-reserve populations is unknown, and it is currently not possible to determine causes for the

differences between reserve and non-reserve populations in Central California. A more

definitive understanding of the consequences of reserve establishment would require creation of

larger reserves in concert with well-designed and funded monitoring studies over many years.
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4) Do the reserves in Central California increase educational opportunities?

Marine reserves provide an opportunity to teach people about undisturbed marine

ecosystems. High school and university educators and researchers frequently use the existing

reserves in Central California. In that respect, existing marine reserves contribute to educational

opportunities. Only the Point Lobos Marine Reserve typically provides educational activities for

the general public, however.

5) Do the reserves in Central California increase recreational opportunities and tourism?

Marine reserves provide an opportunity for people to see undisturbed marine ecosystems.

Recreational activities that do not damage or alter habitats or species in a reserve can provide

social and economic benefits to local communities, subject to social and ecological carrying

capacities. Recreational use of marine reserves can lead to resource damage if the number of

people using the reserve is too high or the type of activities allowed are not compatible with local

resources. Only the Point Lobos Marine Reserve provides recreational activities for the general

public, however, and recreational use there is highly regulated.

6) Do the reserves in Central California provide sustainable environmental benefits?

Marine reserves can provide benefits that go beyond the protection of harvested species.

These benefits can include protection of shoreline habitats, improvement of water quality,

bioremediation of chemical and oil spills, and facilitation of a variety of ocean-atmospheric or

nutrient cycling processes. Benefits accrued are dependent upon reserve location and the

regulatory actions near the reserve. Benefits may also accrue from enhanced biological

processes in the reserve, or because of increased regulatory measures that often co-occur with

reserve formation. There is no evidence that water quality inside existing marine reserves is any

better than the water quality in adjacent areas. The limited area encompassed by existing marine

reserves in Central California indicates any reserve benefits are at best provided only to a small

degree. The increased awareness of water quality issues, and increased attention to marine water

quality by California regulatory agencies, that has occurred since the establishment of

California’s National Marine Sanctuaries, is helping to maintain or improve the relatively high

level of water quality that occurs in Central California.

7) Do the reserves in Central California provide protection of cultural heritage?

Marine reserves can be used to protect specific areas such as archaeological sites,

shipwrecks, sacred locations, or other culturally important features. The California coast

contains many of these types of cultural attributes. Thus, existing marine reserves in Central

California may contain unique or special cultural features which are not currently identified.
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Summary

The exceedingly small size of existing marine reserves in Central California prevents them

from achieving many of the goals and benefits attributed to marine reserves in the scientific

literature. The number of fish and invertebrates inhabiting existing reserves is small, compared

to the total population sizes of species in Central California. Existing reserves in Central

California protect a variety of shallow water habitats and species, but do not provide reserve

benefits for animals living in deeper water, unless they reside in existing reserves during a

portion of their life. The older marine reserves in Central California show some of the primary

benefits associated with protection from exploitation, including modest increases in size and

abundance of fishes, but it is difficult to assess the degree to which these benefits represent

pristine conditions. This is to be expected, as the primary fish species inhabiting these reserves

(rockfishes) are slow growing and exhibit sporadic recruitment. Also, new scientific theories

suggest that substantially altered habitats may or may not return to pre-existing states after the

disturbance has been removed.

Marine reserves in other temperate and tropical oceans, and theoretical models of marine

reserves, show substantial conservation and some potential fishery benefits. For these reasons,

we expect marine reserves created in Central California for conservation purposes would accrue

many of the benefits predicted by reserve theory. The extent to which reserves in Central

California would successfully benefit fisheries, however, would depend on a large number of

social and biological factors, such as social acceptance of reserves, fishery effort shifts, catch

regulations, enforcement levels, the proportion of a stock protected in a reserve, rates of

movement and larval production of protected species, and reserve size and location. Currently,

only a small proportion of fished species are protected in reserves. To be an effective fishery

management tool, more area would need to be placed in reserve status, but not so much as to

preclude viable fisheries. If marine reserves are to be developed and successfully used in Central

California as a tool for fisheries management, however, they will need to be integrated into

existing fishery management processes. A structured and well-supported monitoring program,

which clearly identifies a set of effectiveness parameters, will also need to be established to

measure how well reserves achieve stated objectives.

Effective natural resource management requires public participation and buy-in to

management goals, objectives, and regulations. Thus, just as it is vital to evaluate marine

reserves for their ecological effectiveness, it is also critical that they be evaluated for their socioeconomic values. In this respect, the use of marine reserves is a public policy decision that must

be made with consideration of human activities. For marine reserves to be an effective public

policy tool in Central California, human use patterns, perceptions, attitudes, and beliefs will need

to be incorporated into the design process. Information about social and economic costs and

benefits should also be incorporated to maximize the effectiveness of a reserve system.

Ultimately, an understanding of how people interact with the biophysical environment is integral

to the design and development of marine reserve goals and objectives.
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Acknowledgements

The Monterey Bay National Marine Sanctuary provided funds to produce this report. We

thank Andrew DeVoegelaere and Erica Burton of the MBNMS research program for their

guidance and support for producing this report. We also thank the home institutions of the

authors for providing the support for the authors to be involved in this project. This work was

supported in part by the University of California Sea Grant Extension Program, the University of

California Santa Cruz, the University of California Santa Barbara, the U.S. Geological Survey,

the California Department of Fish and Game, the National Marine Fisheries Service, and Moss

Landing Marine Laboratories, and the Friends of Moss Landing Marine Labs. Support was also

provided for M. Carr, C. Syms, and J. Caselle by the Partnership for Interdisciplinary Studies of

Coastal Oceans (PISCO), funded by the David and Lucile Packard Foundation.