THE KAHEKILI HERBIVORE FISHERIES MANAGEMENT AREA:

ENHANCING RESILIENCE OF A REEF SHOWING SIGNS OF STRESS IN WEST MAUI, HAWAIIDarla White1, Ivor Williams2, Russell Sparks1

1Hawaii Department of Land and Natural Resources, Division of Aquatic Resources, Maui, 130 Mahalani St., Wailuku HI 967932NOAA National Marine Fisheries Service, Coral Reef Ecosystem Division, 1125B Ala Moana Blvd., Honolulu HI 96814

• Data from the Coral Reef

Assessment and Monitoring

Program showed significant

declines in coral cover (~40% loss

from 1993 – 2005) at the Kahekili

Beach Park Site.

• Regular summer macroalgal

blooms at Kahekili (figures below)

contributed to coral decline.

• Reef stressed and declining, but not

yet fully degraded.

The Kahekili Herbivore Fisheries Management Area

Prohibited

Activities Include:

•Removing or

killing any surgeon

fish, parrotfish, or

chub

•Removing or

killing any sea

urchins

•Fish feeding

Allowed Activities

Include:

•Fishing for or

Removing all other

legally harvested

marine life.

•Using bait and/or

other fish

attractants while

legally fishing.

Abstract

The state of Hawaii recently implemented a fishery management effort to increase the resilience of a coral reef at Kahekili West Maui showing clear evidence of decline and vulnerability. Between 1994

and 2005, ~40% of live coral cover was lost there, coincident with repeated summer blooms of invasive macroalgae. In response, the Kahekili Herbivore Fisheries Management Area (KHFMA) was

established in July 2009. Monitoring begun 18 months before establishment of the KHFMA provides clear evidence of incipient recovery: increased biomass of herbivorous fishes, and cover of benign

algae such as crustose corallines. Outreach partnership efforts with the Coral Reef Alliance and the Ka‘anapali Makai Watch program, have increased general public and fisher awareness and support for

herbivore management efforts. Monitoring data coupled with the innovative strategy have resulted in national recognition and the designation of West Maui's watershed as a priority Pacific watershed by

the US Coral Reef Task Force. Watershed projects designed to reduce land-based stressors should result in further increases in ecosystem resiliency.

Algal blooms at Kahekili in

(left) 2005 of the invasive

Acanthophora spicifera, and

(right) 2001of the native

species Cladophora sericea.Photos R. Sparks, J. Smith.

Figure at right shows trends

in coral and macroalgal

cover prior to creation of

the KHFMA

Bullethead Parrotfish

(Chlorurus spilurus) initial

phase (upper photo) and

terminal phase (lower

photo). Photos J.E. Randall.

Figure to the right shows

steady increase in

contibution of large

individuals to total species

biomass.

Honokowai Park

Lahaina

Wastewater

Reclamation

Facility

Kahekili Beach Park

Keka`a Point (Black Rock)

Background

The causes and consequences of those algal blooms are complex, it is reasonable

to expect that protection of reef herbivores can reduce the severity and frequency

of algal blooms and, therefore, can help to check and potentially reverse the

downward trend in condition of Kahekili reefs.

o Initially depleted herbivorous fish stocks compared to Marine Life

Conservation Areas

o Acanthophora spicifera is a preferred edible of herbivores

o Reef still had the structural complexity to support fish life

Factors Favorable to Herbivore Management Strategy

-

0.25

0.50

0.75

1.00

1.25

1.50

6-10 11-15 16-20 21-25 26-30 31-35 36-40

2008/9

-

0.25

0.50

0.75

1.00

1.25

1.50

6-10 11-15 16-20 21-25 26-30 31-35 36-40

2010

-

0.25

0.50

0.75

1.00

1.25

1.50

6-10 11-15 16-20 21-25 26-30 31-35 36-40

2011

-

0.25

0.50

0.75

1.00

1.25

1.50

6-10 11-15 16-20 21-25 26-30 31-35 36-40

2012

-

0.25

0.50

0.75

1.00

1.25

1.50

6-10 11-15 16-20 21-25 26-30 31-35 36-40

2013

0%

2%

4%

6%

8%

10%

12%

- 2 4 6 8 10

CC

A C

ove

r (%

)

Parrotfish Biomass (gm-2)

Relationships Between Parrotfish Biomass & CCA Cover

-

5

10

15

20

25

2008 2009 2010 2011 2012 2013

Bio

mas

s (g

m-2

)

Surgeonfish Biomass at KHFMA

-

2

4

6

8

2008 2009 2010 2011 2012 2013

Bio

mas

s (g

m-2

)

Parrotfish Biomass at KHFMA

Interim Results

Clear increase in parrotfish biomass and

slightly less in surgeonfish.

Increase in biomass of larger size classes of

parrotfish – is evidence that more fishes are reaching older and larger life stages = increased grazing and reproductive capacity

-

0.100

0.200

0.300

0.400

0.500

0.600

2007 2008 2009 2010 2011 2012 2013 2014

Co

ver

(%)

Benthic Cover at KHFMA (all habitats combined)

HardCoralCCA

Turf

Reef Benthos

• Initial decline in coral cover, which has subsequently

flattened out.

• Macroalgal cover has declined to near zero (but was

neveauir >~5% across whole KHFMA)

• No macroalgal blooms since 2006

• CA has increased to around 8% from ~ 2% pre closure

Looking ahead. The mechanisms by which protection of herbivores could

increase reef resilience and coral recovery involve (i)

promotion of benign algal forms (e.g., crustose coralline algae

[CCA], which are important for coral settlement), and (ii)

reduction of algae that can overgrow, smother, or otherwise

negatively affect corals. The full effects of the KHFMA on

fishes and corals will only become evident over a much longer

period of time. However, results show a strong positive

relationship between total parrotfish biomass and total CCA

cover (see fig ->), suggesting that further increases in

parrotfish biomass will have additional positive effects.

The Hawai’i Division of Aquatic Resources (DAR) in partnership with the University

of Hawai’i began a comprehensive monitoring program at Kahekili in January 2008.

That program has been maintained using consistent methods and survey design, but

implemented by DAR and NOAA CRED personnel since 2010. Monitoring involves

1–2 “rounds” per year, generally spring and late summer, with each round comprising

co-located surveys of fishes, urchins, and benthos (e.g., corals and algae) at~80–100

haphazardly located sites. The figure below shows data from April 2012: each bubble

orresponds to either fish biomass or algal cover (%).

Coral Reef Monitoring

West Maui Priority Watershed

The West Maui region, including Kahekili, became a ‘priority site’ for the state

coral management program in 2010. In 2011 the US coral reef task force picked

West Maui as one of 2 Pacific priority watersheds. Those designations and other

factors contributed to a 2012 MOA between DLNR and the Army Corps to work

collaboratively on a planning initiative for watersheds from Waihikuli to Honolua,

known at the West Maui Ridge to Reef Initiative.

A working group created to help advise the process is composed of land

owners/managers, resource users, farmers, and various agency representatives. Its

focus remains on watershed management activities with direct links to adjacent

coral reefs. Active outreach partnership efforts with the Coral Reef Alliance and the

Ka‘anapali Makai Watch program, have increased general public and fisher

awareness and support for herbivore management efforts. Thus, the KHFMA has

contributed to and spurred on more proactive management of the wider area.