What happens to reef fish after coral bleaching?

by Adel Heenan

For the past month, researchers aboard the NOAA Ship Hi‘ialakai have been navigating across the Pacific Ocean to survey coral reef ecosystems at remote Wake Atoll and the Mariana Archipelago. This expedition includes additional surveys at Jarvis Island, in the Pacific Remote Islands Marine National Monument, to assess the reef condition and degree of recovery from a catastrophic coral bleaching event in 2014-2015.


Jarvis Island is located in the central Pacific Ocean, close to the equator, and is a small island in the direct path of a deep current that flows east (Figure 1). Because of it’s position right on the equator and the strong currents hitting the island, Jarvis sits in the middle of a major upwelling zone—where cold nutrient rich water is drawn up from the deep. This water fertilizes the whole area, elevating nutrient levels and productivity in the reef ecosystem (Gove et al., 2006). As a result, Jarvis supports exceptionally high biomass of planktivorous and piscivorous fishes (Williams et al., 2015).

Because it is unpopulated and extremely remote, Jarvis provides an important reference point and opportunity to understand the natural structure, function, and variation in coral reef ecosystems. The island also offers a natural laboratory in which the effects of ocean warming can be assessed in the absence of stressors that impact coral reefs where humans are present (e.g., fishing or land-based sources of pollution).

El Niño, La Niña and the global coral bleaching event of 2014-2015
The Equatorial Pacific upwelling at Jarvis alternates between warm El Niño years, when upwelling is weak and oceanic productivity low, and cold La Niña years where upwelling is strong and productivity is high (Gove et al., 2006). Unusually warm sea surface temperatures, and a strong El Niño in 2014-2015, triggered the third recorded global coral bleaching event. At Jarvis, these warmer waters led to widespread coral bleaching and mortality. High sea surface temperatures in 2015 also impacted upwelling at Jarvis, as evidenced by a decrease in the primary productivity around the island.

Teams from the Coral Reef Ecosystem Program recently completed ecological monitoring at Jarvis from April 2–5, 2017. They collected data at 28 stationary point count sites (Figure 2) this year, 30 in 2016, 62 in 2015, 42 in 2012, and 30 in 2010.

FIG2_SPC

Figure 2. The stationary point count method is used to monitor the fish assemblage and benthic communities at the Rapid Ecological Assessment (REA) sites.

Main Observations
Fish biomass tended to be highest on the western side of the island where equatorial upwelling occurs (Figure 3). In 2016, we observed somewhat reduced total fish and total planktivore biomass (Figure 4), but this reduction was within the normal range of observed variability.

There were some significant reductions observed for individual species in 2016. These reductions were noticeable across multiple trophic groups, for instance the planktivorous Whitley’s fusilier (Luzonichthys whitleyi), Olive anthias (Pseudanthias olivaceus), Dark-banded fusilier (Pterocaesio tile), the piscivorous Island trevally (Carangoides orthogrammus), and the coral-dwelling Arc-eyed hawkfish (Paracirrhites arcatus) which is strongly associated with Pocillopora coral heads. Some of these species had returned to previous ranges by 2017, but others remain depleted (Figure 5).

FIG5_FishBiomass

Figure 5. Mean species biomass (± standard error) per survey year at Jarvis.

Very high levels of coral mortality were evident in 2016 surveys and coral cover remained low in 2017. Notably, macroalgal cover increased in 2017, approximately by the amount of coral cover lost in 2016 (Figure 6).

FIG6_PercentCover

Figure 6. Mean percentage cover estimates (± standard error) of benthic habitat per survey year at Jarvis. Data shown for Hard Coral (top, red); macrolagae (middle, green) and CCA: crustose coralline algae (bottom, orange). Note: no benthic data are available for 2008 as we began collected rapid visual estimates of these benthic functional groups in 2010.

Whether this reduction in specific planktivore, piscivore, and live coral-dwelling fish species is a widespread and long-standing shift in the fish assemblages at Jarvis will be the subject of forthcoming research. It seems plausible that they reflect impacts of a prolonged period of reduced food availability and changes to preferred habitat due to the anomalous warm sea conditions in 2014–2015. Our teams will return to Jarvis in 2018 to conduct another assessment in an attempt to answer some of these questions.

FIG7_shark

An emaciated grey reef shark (Carcharhinus amblyrhynchus) observed during a 2017 fish survey. (Photo: NOAA Fisheries/Adel Heenan)

Additional detail on survey methods and sampling design are available in the full monitoring brief: Jarvis Island time trends 2008-2017.

References
Gove J. et al. (2006) Temporal variability of current-driven upwelling at Jarvis Island. J Geo Res: Oceans 111, 1-10, doi: 10.1029/2005JC003161.
Williams I. et al. (2015) Human, oceanographic and habitat drivers of central and western Pacific coral reef fish assemblages. PLoS 10: e0120516, doi: 10.1371/journal.pone.0120516.

 

SE16-02: American Samoa Reef Fish Survey Summary

by Adel Heenan and Marc Nadon

For the past three weeks, the NOAA Ship Oscar Elton Sette has been the support platform for the Pacific Islands Fisheries Science Center’s reef fish survey project. This research project was led by the NOAA Coral Reef Ecosystem Program (CREP), with partner agency representatives from the American Samoa Department of Marine and Wildlife Resources (DMWR) and the Bigelow Laboratory of Ocean Sciences. The mission was similar to the Pacific RAMP work, but with a particular focus on surveying reef fish assemblages.

Divers collected length observations for all reef fishes recorded during their underwater surveys. To do so accurately, trained divers regularly practice fish sizing using wooden cut-outs in-between research cruises. Length measurements for each reef fish surveyed allows an estimation of biomass by using pre-determined length-weight relationships. Furthermore, it is also used to estimate the size composition of fish populations and obtain a key indicator of population status: average length of exploited size classes. The reason we use this indicator is intuitive: as the exploitation rate of a fish population increases, fewer individual fish have a chance to reach older ages, and therefore, fewer individuals reach larger sizes. Mathematical expressions developed in the 1950s by fisheries scientists can actually relate average length to current fishing mortality rates, and these can be used in computer population simulations to investigate current stock status and generate management advice.

4.Survey_P.Ayotte

Reef fish survey divers regularly train in estimating fish size by using wooden cut-outs of known sizes (NOAA Photo by Paula Ayotte).

Outlined below is a summary of our recently completed survey efforts. More detailed survey results will be available in a forthcoming survey report.

Sampling effort

  •  Ecological monitoring took place in American Samoa from April 15 2016- May 5 2016.
  • Data were collected at 202 sites. Surveys were conducted at Ofu and Olosega (n=11), Rose (n=47), Tau (n=50) and Tutuila (n=94).
  • At each site, the fish assemblage was survey by underwater visual census and the benthic community rapidly assessed.
  • At a subset of sites (n=51), paired comparisons of fish surveys performed using closed circuit re-breathers versus open circuit SCUBA were conducted. Those data will be analyzed and presented in a separate publication.
TCW_rebreather

Diver conducts reef fish survey with a closed circuit re-breather (NOAA photo by Tate Wester).

Overview of the data collected

Primary consumers include herbivores (which eat plants) and detritivores (which bottom feed on detritus), and secondary consumers are largely omnivores (which mostly eat a variety of fishes and invertebrates) and invertivores (which eat invertebrates).

Spatial sampling design

Survey site locations are randomly selected using a depth-stratified design. During project planning and the project itself, logistic and weather conditions factor into the allocation of monitoring effort around sectors of each island or atoll. The geographic coordinates of sample sites are then randomly drawn from a map of the area of target habitat per study area. The target habitat is hard-bottom reef, the study area is typically an island or atoll, or in the case of larger islands, sectors per island, and the depth strata are shallow (0-6 m), mid (6-18 m), and deep (18-30 m).

Sampling methods

A pair of divers surveys the fish assemblage at each site using a stationary-point-count method (Figure 5). Each diver identifies, enumerates, and estimates the total length of fishes within a visually estimated 15-m-diameter cylinder with the diver stationed in the center. These data are used to calculate fish biomass per unit area (g m-2) for each species. Mean biomass estimates per island are calculated by weighting averages by the area per strata. Island-scale estimates presented here represent only the areas surveyed during this project. For gaps or areas not surveyed during this project, data from this and other survey efforts will generally be pooled to improve island-scale estimates.

Fig5.REA_method

Figure 5. Method used to monitor fish assemblages and benthic communities at the Rapid Ecological Assessment (REA) sites.

Each diver also conducts a rapid visual assessment of reef composition, by estimating the percentage cover of major benthic functional groups (encrusting algae, fleshy macroalgae, hard corals, turf algae and soft corals) in each cylinder. Divers also estimate the complexity of the surface of the reef structure, and they take photos along a transect at each site that are archived to allow for future analysis.

About the monitoring program

Pacific RAMP forms a key part of the National Coral Reef Monitoring Program of NOAA’s Coral Reef Conservation Program (CRCP), providing integrated, consistent, and comparable data across U.S. Pacific islands and atolls. CRCP monitoring efforts aim to:

  • Document the status of reef species of ecological and economic importance.
  • Track and assess changes in reef communities in response to environmental stressors or human activities.
  • Evaluate the effectiveness of specific management strategies and identify actions for future and adaptive responses.

In addition to the fish community surveys outlined here, Pacific RAMP efforts include interdisciplinary monitoring of oceanographic conditions, coral reef habitat assessments and mapping. Most data are available upon request.

For more information:

CREP publications

CREP monitoring reports

CREP fish team

Fish team lead and fish survey data requests: ivor.williams@noaa.gov, adel.heenan@noaa.gov

 

How can an ecosystem approach be used to address climate change?

By Adel Heenan and Amanda Dillon
Figure 1. Potential pathways for climate driven impacts on fisheries systems. Projected changes in climate and ocean properties (top tier) in response to increased CO2 emissions will directly affect human and natural capital (bottom tier). Changes in these aspects of the ocean will affect fishes and their related ecosystems (second tier) which will amplify through the fishery system, affecting aspects of fishing catch and effort (third tier). This will in turn have national level societal and economic repercussions (forth tier), in addition to influencing the natural and physical capital of individuals and fishing related communities (bottom tier).

Figure 1. Potential pathways for climate driven impacts on fisheries systems. Projected changes in climate and ocean properties (top tier) in response to increased CO2 emissions will directly affect human and natural capital (bottom tier). Changes in these aspects of the ocean will affect fishes and their related ecosystems (second tier) which will amplify through the fishery system, affecting aspects of fishing catch and effort (third tier). This will in turn have national level societal and economic repercussions (forth tier), in addition to influencing the natural and physical capital of individuals and fishing related communities (bottom tier).

The Pacific Islands Fisheries Science Center’s Coral Reef Ecosystem Division (CRED), in collaboration with scientists from 16 international institutions, recently published a paper in the journal Marine Policy that discusses how coastal fisheries management can incorporate considerations of climate change.

The projected impacts of climate change and ocean acidification on fishes and fisheries in the Asia-Pacific region are being documented with increasing frequency. In turn, these impacts will directly and indirectly effect both natural and human capital (Figure 1). The risks posed by climate change need to be assessed in concert with efforts to address pre-existing threats to tropical fisheries—such as overfishing, habitat degradation, pollution, eutrophication, and invasive species. What is needed is an approach to management that can more effectively deal with these pre-existing stresses, while reducing the vulnerability to longer-term climate impacts. The challenges inherent in achieving this management approach is demanding, particularly in the Asia-Pacific, where coastal fisheries are characterized by a lack of data, limited human capacity for effective management, and weak governance.

This paper focuses on an ecosystem approach to fisheries management (EAFM), which is now widely accepted as a potential solution to the current deficiencies in existing management efforts. The activities required to harness the full potential of an EAFM as an adaptation to climate change and ocean acidification include:

  • provision of the necessary expertise to inform all stakeholders about the risks to fish habitats, fish stocks and catches due to climate change,
  • promotion of trans-disciplinary collaboration,
  • facilitating the participation of all key stakeholders,
  • monitoring the wider fisheries system for climate impacts,
  • and enhancing resources and capacity to implement an EAFM.

By using an “ecosystem approach” to address climate and ocean change, developing countries will build resilience to the ecological and fisheries effects of climate change, and will also address the habitat degradation and overfishing that damages the productivity of coastal fisheries.

For more detail, the full paper is available for download here.

Coral reef monitoring surveys completed around the islands and atolls of American Samoa

By Bernardo Vargas-Ángel
Operating area of the HA-15-01 ASRAMP Legs II and III.

Operating area of the HA-15-01 ASRAMP Legs II and III.

With work complete in the U.S. territory of American Samoa, the NOAA Ship Hi‘ialakai stopped in the port of Pago Pago Harbor for a short pause between Legs III and IV of PIFSC cruise HA-15-01. Led by the PIFSC Coral Reef Ecosystem Division (CRED), this mission marks the seventh monitoring cruise in the American Samoa region by PIFSC staff and partner agencies since 2002.

Activities to monitor the coral reef ecosystems of American Samoa began on February 17 and concluded on March 30, completing Leg I and comprising Legs II and III of this longer Pacific Reef Assessment and Monitoring Program (Pacific RAMP) expedition. Around Tutuila, Aunu‘u, Ofu-Olosega, Swains, and Ta‘u Islands, and Rose Atoll, the CRED scientists conducted ecosystem surveys of fishes, benthic and coral communities, and microbes, along with the deployment of oceanographic instruments and biological installations.

Shallow coral reef communities at Rose Atoll, conspicuously dominated by the pink-colored encrusting coralline algae.

Shallow coral reef communities at Rose Atoll, conspicuously dominated by the pink-colored encrusting coralline algae.

A pair of the reticulated butterflyfish (Chaetodon reticulatus) at Swains Island.

A pair of the reticulated butterflyfish (Chaetodon reticulatus) at Swains Island.

At Rapid Ecological Assessment (REA) sites, surveys for reef fishes and benthic coral communities documented the richness, abundance, density, and sizes of the biota and assemblages as well as the percent composition of bottom-dwelling organisms and the health conditions of coral colonies. Broad-scale towed-diver surveys recorded observational data on large-bodied fishes (>50 cm total length), percent composition of the seafloor, conspicuous macroinvertebrates, and coral stress.

In addition, teams studied microbial communities, diversity of cryptic invertebrates, water temperature, salinity, and carbonate chemistry. They are also working to assess the potential early effects of ocean acidification on cryptobiota (e.g. small, hidden organisms) and the rates of reef carbonate deposition, bioerosion, and coral calcification.

Across the Territory of American Samoa, this mission completed more than 60 towed-diver surveys totaling more than 130 km of coastline, 325 fish surveys, and 180 benthic surveys. The Ocean and Climate Change team deployed four climate monitoring stations around Tutuila, and four around Ofu-Olosega and Ta‘u, containing arrays of subsurface temperature recorders (STRs), calcification accretion units (CAUs), autonomous reef monitoring structures (ARMS), and bioersion monitoring units (BMUs). Critical findings during this mission included observations of coral bleaching, local warm water temperatures, and the number and distribution of corallivore crown-of-thorns sea stars (COTS).

Bleached and partly dead staghorn Acropora outside Fagatele Bay, Tutuila, American Samoa.

Bleached and partly dead staghorn Acropora outside Fagatele Bay, Tutuila, American Samoa.

Bleaching of scleractinian corals, averaging 10% of colonies, was reported in shallow (3-6 m) reef habitats of Tutuila Island—particularly within Fagatele and Fagasa Bays—as well as the southwest coast of the island and primarily affected species of branching and table Acropora, Isopora, Montastrea, Porties, and Pocillopora. Although bleaching conditions did not appear to be widespread, current NOAA Coral Reef Watch forecasts predict persistent warm conditions, which could potentially result in more severe and extensive coral bleaching across the region. CRED scientists recorded only occasional sightings of COTS and their feeding scars on corals, despite the ongoing outbreak conditions reported by staff of the National Park Service and the National Marine Sanctuary of American Samoa. In contrast to other regions where COTS outbreaks have been reported by CRED scientists, including Guam, the Commonwealth of the Northern Mariana Islands, and Kingman Reef, it appears that in American Samoa, the sea stars prefer to feed at night and hide under ledges and overhangs during the day, making them inconspicuous during daylight surveys.

Preliminary results from surveys conducted by CRED fish team divers, during PIFSC cruise HA-15-01, are provided in the fish monitoring brief below.

Pacific Reef Assessment and Monitoring Program
Fish monitoring brief: American Samoa 2015

By Adel Heenan

About this summary brief
The purpose of this summary brief is to outline the most recent survey efforts conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center as part of the long-term Pacific Reef Assessment and Monitoring Program (Pacific RAMP). More detailed survey results will be available in a forthcoming status report.

Sampling effort

  • Ecological monitoring took place in American Samoa from February 15 2015 to March 30 2015.
  • Data were collected at 338 sites. Surveys were conducted at Ofu and Olosega (n=52), Rose (n=47), Swains (n=32), Tau (n=46) and Tutuila (n=162).
  • At each site, the fish assemblage was surveyed by underwater visual census and the benthic community was assessed.

Overview of data collected
Primary consumers include herbivores (which eat plants) and detritivores (which bottom feed on detritus), and secondary consumers are largely omnivores (which mostly eat a variety of fishes and invertebrates) and invertivores (which eat invertebrates).

Figure 1. Mean total fish biomass at sites surveyed.

Figure 1. Mean total fish biomass at sites surveyed.

Figure 2. Mean hard coral cover at sites surveyed.

Figure 2. Mean hard coral cover at sites surveyed.

Spatial sample design
Survey site locations are randomly selected using a depth-stratified design. During cruise planning and the cruise itself, logistic and weather conditions factor into the allocation of monitoring effort around sectors of each island or atoll. The geographic coordinates of sample sites are then randomly drawn from a map of the area of target habitat per study area. The target habitat is hard-bottom reef, the study area is typically an island or atoll, or in the case of larger islands, sectors per island, and the depth strata are shallow (0-6 m), mid (6-18 m), and deep (18-30 m).

Sampling methods
A pair of divers surveys the fish assemblage at each site using a stationary-point-count method. Each diver identifies, enumerates, and estimates the total length of fishes within a visually estimated 15-m-diameter cylinder with the diver stationed in the center. These data are used to calculate fish biomass per unit area (g m-2) for each species. Mean biomass estimates per island are calculated by weighting averages by the area per strata. Island-scale estimates presented here represent only the areas surveyed during this cruise. For gaps or areas not surveyed during this cruise, data from this and other survey efforts will generally be pooled to improve island-scale estimates.

Figure 3. Mean consumer group fish biomass (± standard error). Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 3. Mean consumer group fish biomass (± standard error). Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 4. Mean fish biomass per size class (± standard error). Fish measured by total length (TL) in centimeters (cm).

Figure 4. Mean fish biomass per size class (± standard error). Fish measured by total length (TL) in centimeters (cm).

Each diver also conducts a rapid visual assessment of reef composition, by estimating the percentage cover of major benthic functional groups (encrusting algae, macroalgae, hard corals, turf algae and soft corals) in each cylinder. Divers also estimate the complexity of the surface of the reef structure, and they take photos along a transect at each site that are archived to allow for future analysis.

About the monitoring program
Pacific RAMP forms a key part of the National Coral Reef Monitoring Plan of NOAA’s Coral Reef Conservation Program (CRCP), providing integrated, consistent, and comparable data across U.S. Pacific islands and atolls. CRCP monitoring efforts have these aims:

  • Document the status of reef species of ecological and economic importance
  • Track and assess changes in reef communities in response to environmental stressors or human activities
  • Evaluate the effectiveness of specific management strategies and identify actions for future and adaptive responses

In addition to the fish community surveys outlined here, Pacific RAMP efforts include interdisciplinary monitoring of oceanographic conditions, coral reef habitat assessments and mapping. Most data are available upon request.

For more information
Coral Reef Conservation Program
Pacific Islands Fisheries Science Center
CRED publications
CRED monitoring reports
CRED fish team
Fish team lead and fish survey data requests: ivor.williams@noaa.gov, adel.heenan@noaa.gov

Meaningful monitoring

By Adel Heenan and Ivor Williams

The fish team of the PIFSC Coral Reef Ecosystem Division (CRED) recently published a report summarizing its ecological monitoring activities in 2012–2013. This publication is the first in a new series of annual status reports from the surveys of coral reef fishes and benthic habitats conducted as part of the NOAA Pacific Reef Assessment and Monitoring Program (Pacific RAMP). Its release presents a good opportunity to outline our team’s new communication strategy and to highlight recent efforts to institutionalize more effective monitoring of coral reef fishes in the U.S. Pacific.

To download the ecological monitoring report for 2012–2013, click here.

Why monitor?

Broadly, the purpose of long-term ecological monitoring is to assess the condition of natural resources and detect changes through time. Pacific RAMP includes the following specific objectives:

      • Collecting data and generating information on and documenting the status and trends of coral reef ecosystems, including primary components of the fish and benthic communities and key environmental drivers at U.S.-affiliated jurisdictions in the Pacific;
      • Generating data suitable for assessment of changes in coral reef ecosystems in response to human, oceanographic, or environmental stressors; and
      • Generating data to better evaluate the effectiveness of resource management strategies and policies.

Therefore, the value of data collected through Pacific RAMP depends on both how well it documents spatial patterns and changes across a large geographic area of the Pacific and, most important, how it informs management decisions to sustain coral reef resources. As part of NOAA’s National Coral Reef Monitoring Plan, the Pacific RAMP monitors to detect change in environmental conditions and ecosystem responses on island and regional scales because it is important for assessment of global stressors, such as ocean warming and acidification. The islands monitored span a wide range of potential human impact—from large population centers, such as Oahu, Maui, and Guam, to some of the most remote and pristine coral reefs in the world (e.g., Rose Atoll, the Pacific Remote Islands Marine National Monument, and the Northwestern Hawaiian Islands). As such, CRED data are extremely valuable in the context of a conundrum that sits at the heart of fisheries management: what were coral reefs like in the absence of human influence? More specifically, to know how many fishes were there in the absence of fishing (a concept that is technically referred to as pristine fish abundance) is one of the essential reference points from which maximum sustainable harvest is calculated and, thus, fills a basic information need to support fisheries management decisions.

The large spatial scale at which CRED operates does make it more difficult to assess local or island-scale impacts. In general, many questions that require repeated visits throughout the course of a year or more intensive local sampling are best handled by the jurisdictions’ own monitoring programs. Nonetheless, with a few possible exceptions, the sampling area across which our standardized methods are applied (~40 U.S. Pacific islands and atolls) is globally unique and the data we collect provide an important context for status and trends observed at local levels. For the full potential of Pacific RAMP to be realized, however, CRED’s field surveys need to align with a number of equally important components that make long-term monitoring effective.

What makes ecological monitoring effective?

What constitutes effective monitoring is clearly context specific. It depends on, for example, the variables of interest (e.g., physical vs. biological, species-specific or community-level estimates) and the target quantitative objectives. Within the CRED fish team, we have implemented the following components to make our long-term monitoring efforts more relevant and reliable. To clarify our field sampling method and to establish an institutional memory, the fish team’s standard operation procedure is publicly available (click here to download). The standard operating procedure is currently being revised to include our statistical sampling design.

Before fieldwork begins, the CRED fish team conducts regular observer training focused on fish identification and on fish-size estimation. Once in the field, we continually monitor diver performance in terms of biomass and species richness estimates relative to other divers (Fig. 1). We have a standardized framework centered on transparent, reproducible reporting that has greatly increased our ability for timely and fastidious communication of our data. To make our data meaningful, however, we have to turn it into information. To do so, we have devised a tiered communication strategy.

Figure 1. This diagram illustrates the training, data collection, data processing, and reporting phases the fish and benthic surveys conducted by the fish team for the Pacific Reef Assessment and Monitoring Program.

Figure 1. This diagram illustrates the training, data collection, data processing, and reporting phases the fish and benthic surveys conducted by the fish team for the Pacific Reef Assessment and Monitoring Program.

 

Our new communication strategy for information products

The communication strategy of the CRED fish team has four levels, each of increasing complexity and detail. At the first level, immediately following each cruise leg, which typically cover a region or archipelago, we produce a monitoring brief that outlines our sampling effort and an overview summary of the new data (click herefor access to monitoring briefs). Second, we are committed to producing an annual status report within three months of the new calendar year. This status report presents the new site-level data collected (Fig. 2), sets the regions surveyed in the context of the wider Pacific areas that CRED surveys (Fig. 3), and reports on our diver performance results. The third and fourth tiers provide more in-depth analyses for specific projects. To illustrate, a technical report came from the additional surveys performed around Guam in 2011, surveys that allowed for assessment of the efficacy of marine protected areas (click hereto download NOAA Technical Memorandum NMFS-PIFSC-33).

Figure 2. An example of the site-level data presented in the annual data report, this figure presents the following survey data from sites at Jarvis Island in 2010 and 2012 (top left) identified by depth strata, (top right) total fish biomass recorded at each site per year, (bottom left) hard coral cover (%) assessed by rapid visual assessment, and (bottom right) benthic substrate ratio (hard corals and encrusting algae to turf algae and macroalgae). The substrate ratio indicates the balance between the benthic components that contribute to reef accretion (corals and crustose coralline algae) and the fleshy macroalgae and turf algae that compete for space on the reef.

Figure 2. An example of the site-level data presented in the annual data report, this figure presents the following survey data from sites at Jarvis Island in 2010 and 2012 (top left) identified by depth strata, (top right) total fish biomass recorded at each site per year, (bottom left) hard coral cover (%) assessed by rapid visual assessment, and (bottom right) benthic substrate ratio (hard corals and encrusting algae to turf algae and macroalgae). The substrate ratio indicates the balance between the benthic components that contribute to reef accretion (corals and crustose coralline algae) and the fleshy macroalgae and turf algae that compete for space on the reef.

Figure 3. An example of the Pacific-wide data presented in the annual status report, this figure presents mean fish biomass per size class per U.S. Pacific reef area. Mean fish biomass (± standard error) per size class (0–20, 20–50, and >50 cm in total length [TL]) per reef area, pooled across survey years (2009–2013). Islands are ordered within region by latitude. NWHI=Northwestern Hawaiian Islands, MHI=main Hawaiian Islands, N.Mariana=northern Mariana Archipelago, S.Mariana=southern Mariana Archipelago, PRIA=Pacific Remote Island Areas, and Samoa=American Samoa.

Figure 3. An example of the Pacific-wide data presented in the annual status report, this figure presents mean fish biomass per size class per U.S. Pacific reef area. Mean fish biomass (± standard error) per size class (0–20, 20–50, and >50 cm in total length [TL]) per reef area, pooled across survey years (2009–2013). Islands are ordered within region by latitude. NWHI=Northwestern Hawaiian Islands, MHI=main Hawaiian Islands, N.Mariana=northern Mariana Archipelago, S.Mariana=southern Mariana Archipelago, PRIA=Pacific Remote Island Areas, and Samoa=American Samoa.

We welcome comments on how to improve the utility of our data and information products. Comments or suggestions on any of the above content can be submitted to nmfs.pic.credinfo@noaa.gov with the subject line of “For the Attention of the CRED Fish Team Lead.”

Again, to access the 112-page annual status report for 2012–2013, click here. Here’s the full reference for this report:

Heenan A, Ayotte P, Gray A, Lino K, McCoy K, Zamzow J, Williams I. 2014.Pacific Reef Assessment and Monitoring Program. Data Report: Ecological monitoring 2012–2013—reef fishes and benthic habitats of the main Hawaiian Islands, American Samoa, and Pacific Remote Island Areas. Pacific Islands Fisheries Science Center, PIFSC Data Report, DR-14-003, 112 p.

 

Reef monitoring at Wake Island: preliminary results from fish surveys

By Dione Swanson

After departing Honolulu on March 5, the NOAA Ship Hi’ialakai arrived at Wake Island on March 14. It was the first stop for PIFSC cruise HA-14-01, a Pacific Reef Assessment and Monitoring Program (Pacific RAMP) expedition that also recently visited Guam and is currently focused on the southern islands of the Commonwealth of the Northern Marianas Islands. At Wake Island, staff members of the PIFSC Coral Reef Ecosystem Division (CRED) and partners conducted surveys of reef fish assemblages, coral populations, and benthic communities as well as deployed instruments and collected water samples to monitor effects of climate change and ocean acidification on coral reef ecosystems.

Our first 2 planned operational days on Wake Island were canceled because of poor weather conditions (strong winds and high seas). Relatively good weather returned by March 16, and we then were able to complete 4.5 days of small-boat operations before leaving for Guam on March 20. Over the course of our time at Wake Island, scientists accomplished the following field activities during a combined 229 dives: reef fish surveys at 45 Rapid Ecological Assessment (REA) sites; benthic surveys at 20 REA sites; collection of 12 water samples and 1 benthic sample for analysis of microbial communities; retrieval of 7 subsurface temperature recorders (STRs), 6 autonomous reef monitoring structures (ARMs), 15 calcification accretion units (CAUs), and 1 sea-surface temperature (SST) buoy; installation of 4 National Coral Reef Monitoring Plan climate stations—each of which includes 3 ARMs, 5 CAUs, 5 bioerosion monitoring units, and 3 STRs; and collection of 20 water samples for analysis of dissolved inorganic carbon; and completion of 11 shallow-water conductivity, temperature, and depth (CTD) casts.

Highlights of our research dives at Wake Island included incredible water visibility (>45 m), high coral cover that consisted of abundant large colonies with low partial mortality, overall low prevalence of coral disease and bleaching, and large patches of soft corals. There were only a few sightings of bumphead parrotfish (Bolbometopon muricatum) and Napoleon wrasse (Cheilinus undulatus).

Preliminary results from the surveys of reef fishes conducted by scuba divers at Wake Island (depth range: 0–30 m) during this cruise are provided in the below fish monitoring brief, which was issued on March 25 as PIFSC Data Report DR-14-007 (click here, to download a PDF file of this report). Wake Island is 1 of 7 islands, atolls, and reefs that make up the Pacific Remote Island Areas and, under the jurisdiction of the United States, are protected as the Pacific Remote Islands Marine National Monument.

Pacific Reef Assessment and Monitoring Program
Fish monitoring brief: Pacific Remote Island Areas 2014

By Adel Heenan

About this summary brief

The purpose of this document is to outline the most recent survey efforts conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center as part of the long-term monitoring program known as the Pacific Reef Assessment and Monitoring Program (Pacific RAMP). More detailed survey results will be available in a forthcoming annual status report.

Sampling effort

  • Ecological monitoring took place in the Pacific Remote Island Areas from March 16 2014 to March20 2014.
  • Data were collected at 45 sites. Surveys were conducted at Wake Island.
  • At each site, the fish assemblage was surveyed by underwater visual census and the benthic community was assessed.

Overview of data collected

Primary consumers include herbivores (which eat plants) and detritivores (which bottom feed on detritus), and secondary consumers are largely omnivores (which mostly eat a variety of fishes and invertebrates) and invertivores (which eat invertebrates).

Figure 1. Mean total fish biomass at sites surveyed.

Figure 1. Mean total fish biomass at sites surveyed.

 

Figure 2. Mean hard coral cover at sites surveyed.

Figure 2. Mean hard coral cover at sites surveyed.

Figure 3. Mean consumer group fish biomass (± standard error). Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 3. Mean consumer group fish biomass (± standard error). Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 4. Mean fish biomass per size class (± standard error). Fish measured by total length (TL) in centimeters (cm).

Figure 4. Mean fish biomass per size class (± standard error). Fish measured by total length (TL) in centimeters (cm).

 

Spatial sample design

Survey site locations are randomly selected using a depth-stratified design. During cruise planning and the cruise itself, logistic and weather conditions factor into the allocation of monitoring effort around sectors of each island or atoll. The geographic coordinates of sample sites are then randomly drawn from a map of the area of target habitat per study area. The target habitat is hard-bottom reef, the study area is typically an island or atoll, or in the case of larger islands, sectors per island, and the depth strata are shallow (0–6 m), mid (6–18 m), and deep (18–30 m).

Sampling methods

A pair of divers surveys the fish assemblage at each site using a stationary-point-count method (Fig. 5). Each diver identifies, enumerates, and estimates the total length of fishes within a visually estimated 15-m-diameter cylinder with the diver stationed in the center.

These data are used to calculate fish biomass per unit area (g m-2) for each species. Mean biomass estimates per island are calculated by weighting averages by the area per strata. Island-scale estimates presented here represent only the areas surveyed during this cruise. For gaps or areas not surveyed during this cruise, data from this and other survey efforts will generally be pooled to improve island-scale estimates.

Each diver also conducts a rapid visual assessment of reef composition, by estimating the percentage cover of major benthic functional groups (encrusting algae, fleshy macroalgae, hard corals, turf algae and soft corals) in each cylinder. Divers also estimate the complexity of the surface of the reef structure, and they take photos along a transect at each site that are archived to allow for future analysis.

Figure 5. Method used to monitor fish assemblage and benthic communities at the Rapid Ecological Assessment (REA) sites.

Figure 5. Method used to monitor fish assemblage and benthic communities at the Rapid Ecological Assessment (REA) sites.

About the monitoring program

Pacific RAMP forms a key part of the National Coral Reef Monitoring Program of NOAA’s Coral Reef Conservation Program (CRCP), providing integrated, consistent, and comparable data across U.S. Pacific islands and atolls. CRCP monitoring efforts have these aims:

  • Document the status of reef species of ecological and economic importance
  • Track and assess changes in reef communities in response to environmental stressors or human activities
  • Evaluate the effectiveness of specific management strategies and identify actions for future and adaptive responses

In addition to the fish community surveys outlined here, Pacific RAMP efforts include interdisciplinary monitoring of oceanographic conditions, coral reef habitat assessments and mapping. Most data are available upon request.

For more information

Coral Reef Conservation Program: http://coralreef.noaa.gov

Pacific Islands Fisheries Science Center: http://www.pifsc.noaa.gov/

CRED publications: http://www.pifsc.noaa.gov/pubs/credpub.php

CRED fish team: http://www.pifsc.noaa.gov/cred/fish.php

Fish team lead and fish survey data requests: ivor.williams@noaa.gov