Coral Reef Condition Status Report for American Samoa
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2018 Coral reef condition: GOOD A status report for AMERICAN SAMOA Coral reefs are important Healthy coral reefs are among the most biologically diverse ecosystems on Earth, with high cultural and economic significance. They provide billions of dollars in food, the results are in! jobs, recreational opportunities, coastal protection, and other important goods and services to people around the • Overall, American Samoa reefs are in world. The global decline in coral reefs has had significant ecological, social, cultural, and economic impacts on people good condition. and communities. • Tutuila is most impacted by human The National Oceanic and Atmospheric Administration (NOAA) Coral Reef Conservation Program (CRCP) leads activities, whereas the uninhabited efforts to monitor and conserve coral reef resources and islands and atolls are least impacted. the ecosystem services they provide for current and future generations. In 2011, CRCP established the National Coral Reef Monitoring Program (NCRMP)—an integrated and • American Samoa's coral reefs would focused monitoring effort with partners across the U.S. and benefit the most from reduced fishing its territories. Scientists collect biological, physical, chemical, and socioeconomic data to provide a robust picture of pressure and less temperature stress. the condition of U.S. coral reefs and inform management decisions. For more information, visit coralreef.noaa.gov . reefs are under threat Coral reefs are sensitive ecosystems that thrive when directly harm or kill corals, and also indirectly affect reefs conditions are right—warm, clear, shallow waters that by disrupting critical ecological functions, food webs, and contain low nutrient levels. However, factors at both local fish populations. and global scales can disrupt these conditions. Threats such as fishing impacts and land-based sources of pollution Climate change and ocean acidification impacts threaten can be managed at a local level, while coral reefs will also coral reefs at local to global scales through sea-level rise, benefit from the reduction of greenhouse gases that fuel mass coral bleaching, and disease outbreaks. Increasing climate change and ocean acidification. water temperatures and ocean acidification reduce coral growth. In the long term, failure to reduce carbon Over-fishing leads to a reduction in the amount of reef fish dioxide and other heat-trapping gases that cause ocean species in many locations, which can disrupt the delicate acidification and rising temperatures will continue to impede ecological balance on the reef. Physical impacts from conservation and management efforts for coral reefs. fishing activities, like anchoring and marine debris, can also damage coral reefs. Derelict fishing gear such as gill nets, trap line, and monofilament fishing line is prevalent in American Samoa and can entangle and kill reef organisms. why a status report? Land-based sources of pollution result from agriculture, Effective coral reef conservation cannot be accomplished deforestation, land clearing, storm water, impervious without an informed and engaged public. This status report surfaces, coastal development, road construction, and oil is part of an ongoing series of documents to track the status and chemical spills. This pollution impacts coral reefs in and trends of coral reefs across the U.S. and its territories. many ways, including 1) sedimentation, which smothers The American Samoa coral status report is part of a corals with dirt, 2) nutrient enrichment, which can lead to larger effort to provide communities and decision-makers overgrowth of corals by seaweeds, and 3) the introduction with information about managing and conserving coral of toxins and diseases into the system. These pollutants can reef ecosystems. Corals & algae fish Corals & algae make up the base of the coral reef Coral reefs serve as habitat and food for fish species. ecosystem, providing food and shelter for fish, shellfish, and These fish are important to the ecology of the reef, national marine mammals. They are also important economic and and global economies, and the livelihoods of local villagers. tourism resources. The five indicators for corals & algae are: The four indicators chosen for fish are: • Coral reef cover, which includes corals, algae, and • Reef fish, a measure of the amount of fish present. crustose coralline algae. • Sustainability, which is indicative of whether fishery • Coral populations, a measure of the population's ability stocks still have abundant large breeding-sized fishes. to reproduce and sustain itself. • Sharks and other predators, a measure of the amount • Herbivory, a measure of the level of grazing pressure of fish that eat other fish. by fish on corals and algae. • Diversity, a measure of the number of different • Mortality, which measures the amount of recently species of fish present. dead coral. • Diversity, a measure of the number of different species Sharks are important to the ecological function of of coral present. coral reefs. Their removal negatively affects the entire coral reef food web. Shark populations in American The coral-eating crown-of-thorns sea star (COTS) has Samoa today are only 4–8% of historical populations. a serious impact on Indo-Pacific reefs. Several recent Large reef fish such as Bumphead parrotfish are COTS infestations on American Samoa reefs may be considered locally extinct while others like Humphead linked to nutrient inputs. Corals at Swains and Tutuila Wrasse are heavily pressured. Local management Islands experience most of the impacts. actions such as banning SCUBA spearfishing and the take of large reef fish species, if properly supported and enforced, will help these fish populations recover. A National Park of American Samoa diver injects a COTS with ox bile, a natural substance that kills the creature but Sharks, such as this blacktip reef shark in American does no harm to the reef. Photo: National Park Service. Samoa, are a critical component of coral reef food webs. Photo: National Oceanic and Atmospheric Administration. average coral cover biomass of large fish 70 Tutuila Tau 40 Tutuila Tau 60 Swains Ofu & Olosega Swains Ofu & Olosega Rose 30 Rose 50 40 20 30 ) offish) large (>50cm) 20 2 Percent cover Percent 10 10 0 0 4 6 8 0 2 5 2 4 6 8 0 2 5 0 0 0 1 1 1 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 Biomass (g/m 2 2 2 2 2 2 2 2 2 2 2 2 2 Year Year Coral cover in American Samoa has stayed relatively the Biomass of large fishes is highest at Swains, where same throughout the period of record. However, coral large schools of barracuda and jacks are frequently cover at Swains has recently declined. encountered, and tends to be lowest at Tutuila. AMERICAN SAMOA CORAL REEFS ARE IN GOOD CONDITION american samoa swains island A L S O R & Swains Island is approximately 1.5 square miles with C GA American Samoa is an unincorporated United States Territory in the South A L E Juvenile coral a maximum elevation of six feet above sea level. Only Pacific. The Territory consistsof five volcanic islands and two atolls, all Adult coral a few people lived on Swains in the past. The island C surrounded by fringing coral reefs. American Samoa was divided into 0 1 km Coral reef L six sub-regions to evaluate condition of four categories—corals & 0 1 mi N has been recently abandoned, leaving it currently cover I 85 Herbivory Mortality ersity algae, fish, climate, and human connections. American Samoa uninhabited. Swains is almost completely protected M H Div A S Temper by the National Marine Sanctuary of American Samoa. I coral reefs are in good condition overall. Benthic cover and T F AL Sharks E stressatur COR S & coral populations are doing well. In contrast, fish are Swains Island’s coral reefs are doing well and scored e ALGAE Other predators moderately to very impacted. Sharks and other the highest out of the six regions. predators are considered depleted throughout E Sustainability T H H the world and American Samoa is no Ocean A S M I acidification I exception. Climate is also a factor negatively F L Reef C 80 fish affecting coral reefs. Temperature stress muliava rose atoll A L S and ocean acidification are global ( ) O R & C H * Rose Atoll is the easternmost Samoan island and the C LGAE O UMAN S Diversity problems seen locally in American Samoa. A NNECTION Reef growthmaterial Despite these issues, communities are southernmost point of the United States. One of the C l r o n m e n t a a t n e m n o r l Awareness I C A N S A smallest atolls in the world, Rose Atoll consists of engaged and informed about management L t for M E R M O A about 0.03 square miles of land, 2.5 square miles I o r i b e h a v v a h e b i r o actions to protect reefs. Of the 70 villages A 84 M H 0 1 km Suppor of lagoon, and a narrow barrier reef. Rose Atoll is actions v n -e o r P i in American Samoa, 20% have resource A S management 0 1 mi N almost completely protected as a Marine National I management plans in place, 7% of coral reef area T E F is under no-take designation, and 25% of coral reef Monument and the land and lagoon area is protected area is designated under management. The coral reefs by a National Wildlife Refuge. Rose Atoll's coral reefs on American Samoa's remote islands experience fewer impacts Coral reef habitat are doing well. from human activities and development, but overall the Territory is struggling against threats, such as pollution, overfishing, and global climate change.