The HICEAS adventures continue: Two ships join forces to search for whales and dolphins in Hawaiian waters

By Amanda Bradford and Jeff Moore
HICEAS Cruise Leaders

When we last checked in on the progress of the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS), the first leg of HICEAS 2017 aboard the NOAA Ship Oscar Elton Sette had been completed.  A lot has happened since then!  To begin with, the Sette finished its second leg while the NOAA Ship Reuben Lasker joined the survey and accomplished its first HICEAS leg.  The Lasker traveled to the Hawaiian Islands study area from its home port in San Diego, CA, a journey that took almost 9 days and spanned approximately 2,000 nautical miles.  Here, we fill you in on our respective trips as HICEAS Cruise Leaders, Amanda on the Sette and Jeff on the Lasker.

Sette’s Second Sail

After a brief in-port following the first leg, the Sette set sail again on August 8 for a 29-day journey that ended on September 5.  Sette Leg 2 focused on the northern portion of the study area, from above the main Hawaiian Islands in the east to the far northwestern reaches above Midway and past the International Dateline.  We were pretty lucky with weather during this leg, with a majority of our 2,315 nautical miles of daytime visual effort occurring in Beaufort sea state conditions of 4 or less, which is atypical thanks to our persistent trade winds.  With the improved sea conditions, we were better able to visually detect groups of cetaceans (whales and dolphins), which is reflected in a relatively high number of cetacean sightings – 70 groups in total.  Nevertheless, we had several days with great weather when we did not see or hear any cetaceans.  On these days, we were far from land and in-between the seamounts that dot the region.  We were reminded that parts of our study area are often referred to as a “tropical desert” because the nutrient-poor waters make it difficult to support high densities of cetaceans.

Lucky 13! That is, the 13 scientists who worked tirelessly to collect data on cetaceans and seabirds during Sette’s Leg 2 of HICEAS 2017. From left to right: Rory Driskell, Ali Bayless, Erik Norris, Adam Ü, Chris Hoefer, Amanda Bradford, Joe Fader, Allan Ligon, Amy Van Cise, Jennifer Keating, Dawn Breese, Andrea Bendlin, and Paula Olson. Photo credit: NOAA Fisheries/Hung “Doc” Tran

The 70 sightings made by the cetacean observers included at least 13 species, ranging from the small spinner dolphin to the large Bryde’s whale.  The most frequently sighted species was the striped dolphin, seen a whopping 14 times, followed by the short-finned pilot whale, which was seen 10 times.  Most other species were seen only 1-2 times.  Our most exciting sightings were of beaked whales, which are elusive and difficult to detect.  First, we had 2 sightings of Longman’s beaked whales, including a group with almost 100 animals, a rare and poorly-known species.  Then, we had a small group of Blainville’s beaked whales approach the ship very closely multiple times during an extended period at the surface, seemingly as curious about us as we were about them.  We took almost 10,000 photos during these cetacean sightings, from both the ship and 7 launches of the small boat.  We collected 33 biopsy samples (small tissue plugs used for genetic and other analyses) from 4 species (spotted, rough-toothed, and bottlenose dolphins and short-finned pilot whales) and deployed satellite tags on 3 short-finned pilot whales to study the movements of these individuals.

Daytime survey effort (white lines) and cetacean sightings (see legend) made within the Hawaiian EEZ (blue line) during HICEAS 2017 Leg 2 aboard the Oscar Elton Sette. The red shading is a focus area around the main Hawaiian Islands, and the area shaded in green is the Papahānaumokuākea Marine National Monument, with slightly darker shading showing where the Monument was expanded in 2016.

The acoustics team was also busy, detecting 127 vocal groups of cetaceans.  They also kept our Drifting Autonomous Spar Buoy Recorder, aka DASBR, project going.  During Sette Leg 2, we released 7 DASBRs to listen for vocalizing cetaceans in our absence and picked up 3 others from Leg 1 that were full of data!  We also deployed 43 sonobuoys that allow us to detect vocalizing baleen whales that may be in the area.  The seabird observers recorded thousands of bird sightings from at least 35 species, with the Herald/Henderson’s Petrel, Flesh-footed Shearwater, Sooty Shearwater, Parasitic Jaeger, and Pacific Golden Plover all new species for HICEAS 2017.  The Pacific Golden Plovers were returning to their wintering grounds in Hawai’i after spending a summer in Alaska.  Named Kōlea in Hawaiian, these shorebirds are known to return to the exact same location year after year, even the same yard!  Although seabirds tell us a lot about ocean productivity in our study area, we also conducted 35 CTD (Conductivity-Temperature-Depth) casts to learn more about the physical properties of the waters we surveyed.  Finally, while we rarely saw the species we were targeting for health assessment using an Unmanned Aircraft System (UAS aka drone) when the winds were light, we were able to make 6 hexacopter flights over short-finned pilot whales.

Lasker’s Leading Leg

The Lasker left San Diego on August 17 bound for the HICEAS study area.  To get there as quickly as possible, the cetacean observers worked in what we call ‘passing mode,’ when the ship does not leave the trackline to investigate sightings.  As the days passed, we could tell we were approaching the tropics as air and water temperatures got higher, sightings of tropical seabirds increased, and the trade winds made their presence known.  We arrived in the study area in the pre-dawn hours of August 26, conducting our effort from that day forward in ‘closing mode,’ when the ship “closes” on a sighting to have better looks and more time to obtain species identification, group size estimates, and other information.  Our effort focused on the area south and east of the main Hawaiian Islands, where we surveyed until September 5, ending our 20-day leg.  All told, we completed 1,844 nautical miles of daytime visual effort, with 696 nautical miles in Hawaiian waters.  We sighted 53 cetacean groups – 34 of them were in the HICEAS study area.

Fabulous 14! The ace scientific complement during Lasker’s Leg 1 of HICEAS 2017 (sending birthday greetings to two members of Team Sette). From left to right: Mark Cotter, Heather Colley, Andy Bankert, Jenny Trickey, Jim Gilpatrick, Shannon Coates, Jeff Moore, Suzanne Yin, Seth Sykora-Bodie, Megan Slack, Juan Carlos Salinas Vargas, Marie Hill, Bernardo Alps, and Mike Force. Photo credit: NOAA Fisheries/PJ Klavon

The 34 sightings of cetaceans in the study area were from 10 identified species – all species seen during Sette Leg 2, with the exception of the pygmy killer whale.  We collected 2 biopsy samples, one from a spotted dolphin and another from a rough-toothed dolphin.  Like the Sette, we saw Longman’s beaked whales (although 3 times!), which was a highlight for us also.  However, our other exciting cetacean detections occurred acoustically.  One night, at about 10 pm, a few of us were gathered in the acoustics lab.  The hydrophone array was still in the water recording, but no one was actively monitoring it, as is usually the case once the sun sets and the observers go off effort.  At just the right moment, faint calls appeared on the computer monitor, and we decided to put the headphones on to listen. Good thing, because killer whales were in the area and gave us quite a performance.  We were treated to a vocal repertoire that sounded somewhat Shamu-like and lasted for over an hour.  If only there had been light left outside to see the animals because it would have been a spectacular encounter.

Daytime survey effort (white lines) and cetacean sightings (see legend) made during HICEAS 2017 Leg 1 aboard the Reuben Lasker, including its transit to the Hawaiian EEZ (blue line). The red shading is a focus area around the main Hawaiian Islands, and the area shaded in green is the Papahānaumokuākea Marine National Monument.

The most memorable moment of Lasker Leg 1 took place when the acoustic team began detecting the Cross Seamount beaked whale an hour before dusk.  This beaked whale, first heard at Cross Seamount, is known only from acoustic recordings and sounds unlike any known beaked whale species with acoustic recordings.  With the long, upswept vocalization clicks, there was no doubt that we had found this mystery beaked whale.  We acoustically tracked the animal(s) for over an hour hoping to at long last visually identify the species making these clicks.  As the sun went down, we were losing hope.  Darkness set in, but right before it did, our amazing Lead Cetacean Observer, Suzanne Yin, caught a glimpse of a cetacean that might have been our unknown whale.  Unable to get a good look and confirm the species, we at least got one step closer to identifying the mysterious Cross Seamount beaked whale!  Overall for acoustics, there were 106 detections of cetacean groups during Lasker Leg 1, and we picked up 2 DASBRs.  Finally, the seabird observers encountered 4,916 birds (of at least 15 species) in 28 feeding flocks and recorded 1,830 birds (of at least 42 species) during their strip-transect survey effort.

The Sette Leg 2 and Lasker Leg 1 teams appreciated the help of their visiting scientists, Duke University graduate students Joe Fader (Sette) and Seth Sykora-Bodie (Lasker), who wrote a great blog post about their experiences.  The Sette and Lasker went back to sea for their respective third and second legs on September 11.  Keep checking the HICEAS website for more information on what happened next!

All photos taken under research permit.

Off to a Great Start: the First Leg of HICEAS is Complete

By Erin Oleson
HICEAS Chief Scientist

The Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS) of 2017 is a huge effort. The study area covers over 1.8 million square nautical miles (the entire Hawaiian Exclusive Economic Zone). To comprehensively survey that expansive space, from Hawaiʻi Island in the east to Kure Atoll in the west, takes 2 NOAA ships–the Oscar Elton Sette and the Reuben Lasker–and 187 days at sea over a 5-month period; a total of 7 trips to sea between the 2 ships. This effort began July 6th on the Sette, and the first leg finished up August 2nd. A prolonged effort like HICEAS starts with lots of planning and is maintained by keeping goals front and center and having a little fun along the way. Leg 1 of HICEAS felt a bit like the end for a few of us–so many months of planning and we’re finally at sea–this is the reward. But really, leg 1 was just the beginning.

The HICEAS leg 1 science party—an intrepid group of 15 scientists including mammal and seabird observers, acousticians, unmanned aircraft system (UAS) pilots, and our NOAA Teacher At Sea. Photo credit: NOAA Fisheries/Hung “Doc” Tran

In many ways, the prospect of spending several months on a ship was a bit daunting. As we set sail, the excited, and perhaps nervous, energy was poured into ensuring all the gear and software was working as expected, that the early-survey electronic gremlins were vanquished, and that all of people that make up this effort, from the scientists to the ship’s crew and officers, were working as a team. The early HICEAS jitters were quickly allayed as the data began to stream in, and the natural comraderie of those that have sailed before and those that were new to this adventure. This process was facilitated with the aid of several dozen cans of fizzy water–the ever-present thirst quencher and morale-boosting libation of the HICEAS science team. By the end of the leg, everything was running like a well-oiled machine, ready for the adventure to resume after a short respite on land.

02_FlyingBridge

It’s all hands on deck while the visual survey team counts sperm whales. Sperm whale counts continue for 90 minutes to ensure that all animals are counted over the course of the prolonged deep dives. Photo credit: NOAA Fisheries/Ernesto Vásquez

A normal day during HICEAS starts before dawn with a CTD (Conductivity-Temperature-Depth) Rosette lowered to 1000 meters depth to measure salinities and temperatures of the ocean in the survey area. Before sunrise, the acoustics team deploys the towed hydrophone array and then, just after sunrise, when there’s enough light to reliably sight groups in the distance, the mammal and seabird visual survey teams begin their effort as we transit along one of many tracklines in our survey design. Throughout the day, as cetacean groups are sighted or heard (using underwater acoustic microphones, or hydrophones), the teams work to identify species, estimate the number of animals in the group, and when conditions are right and the animals allow, collect photographs and tissue samples to support more detailed analyses of population distribution and structure. When sunset comes, the visual and acoustic teams end their searches, and while the onboard Survey Technician casts another CTD, the teams check and summarize the day’s data, process and archive the photos, clean and prep the sampling gear, and prepare to start again the next day. For the acoustics team, the evening CTD just means a shift in operations. As part of the team works to check and archive the day’s data, the other part deploys sonobuoys to listen for baleen whales during the CTD cast. Once the CTD is back on deck, the acoustics team redeploys the towed hydrophone array to listen for chatty cetaceans overnight. At night, many whales and dolphins increase their vocalizations as they forage on a cornucopia of plankton rising from the depths, or on larger fish and cephalopods that follow. While the team sleeps, our gear continues collecting data, never wasting a moment of this effort.

The Main Hawaiian Islands (MHI) is a focal region of the 2017 effort, and where we kicked off our HICEAS adventure. The MHI special focus area includes a higher density of effort in our survey design, carried out both along ‘standard’ tracklines–those that extend from the ESE to WNW reaches of the Hawaiian Archipelago–and along random ‘fine-scale’ tracklines that begin or end where we deploy or retrieve Drafting Acoustic Spar Buoy Recorders (DASBRs). The MHI area is home to several island-associated populations of cetaceans, as well as several human activities that may affect those populations. The additional visual and acoustic survey effort in this region is designed to better assess the distribution and density of those island-associated populations and examine the impacts of human activities in their habitat. HICEAS is funded by a multi-agency coalition of partners with interest in ensuring the sustainability of Hawaiʻi’s cetacean populations, including NOAA Fisheries (that’s us!), the agency responsible for assessing Hawaiʻi’s cetaceans under the Marine Mammal Protection Act and Endangered Species Act, and the U.S. Navy and the Bureau of Ocean Energy Management (BOEM), the agencies responsible for evaluating whether and to what extent the activities they conduct or regulate might impact Hawaiʻi’s cetacean populations.  The multi-agency partnership makes an effort like HICEAS possible, and the joint interest of these agencies in the MHI has spawned the MHI focus area for 2017.

The acoustics team gets ready to deploy a DASBR south of Lanai. Photo credit: NOAA Fisheries/Staci DeSchryver.

The early efforts of the first leg aboard the Sette included several special passive acoustic projects in the MHI focus area. Over the first 12 days, we deployed 8 DASBRs in both leeward and windward waters of the MHI focus area. The DASBRs record ocean sounds, including those produced by cetaceans, for four weeks, providing a rich dataset that can be used to evaluate cetacean distribution and density at a finer scale of time and space than the ship-based portion of the survey could provide alone. The DASBRs are also uniquely suited to locate beaked whales, a clade of deep-diving cetaceans that are often difficult to see in typical Hawaiʻi weather, but also potentially vulnerable to anthropogenic sound. We also recovered and redeployed a High-Frequency Acoustic Recording Package (HARP) off Kona, the location of a long-term acoustic monitoring site that is part of the Pacific Islands Passive Acoustic Network. Redeployment will allow monitoring through the fall, continuing a nearly 11-year record at this location, which has proved invaluable in examining seasonal and inter-annual patterns in cetacean occurrence in this unique Hawaiʻi region. Finally, the Sette crew expertly recovered and redeployed an Ocean Noise Reference Station north of Oʻahu, bringing home two years of calibrated low-frequency ambient noise and cetacean occurrence data that form the beginning of the Hawaiʻi dataset for NOAA’s long-term commitment to monitor and measure ocean noise throughout US waters. The newly-deployed hydrophone will record for another two years.

Aerial images, like of this pair of short-finned pilot whales, are valuable for studying group composition and individual body condition. Photo credit: NOAA Fisheries/Kym Yano and Amanda Bradford

The early portion of the mission also included two days of shake-down flights in predictably calm waters off Kona for our newly-minted hexacopter pilots. The PIFSC Cetacean Research Program has recently invested in the hexacopter as a powerful platform to collect aerial imagery of cetaceans. The images can be used to assess group composition (number of adults, juveniles, and moms with calves) for insights into population demographics, and to measure individual size and shape as a metric of animal health. Our hexacopter team made 14 successful flights, including a number of calibration and practice flights, and several over groups of spinner dolphins and short-finned pilot whales. With these flights, the pilots honed their ability to fly over a group from a distance, evaluate image quality from a small monitor in the boat, and keep up with moving groups while keeping track of parts of the group that have already been photographed. Unfortunately, after leaving Kona, encounters with our target species were never in suitable weather conditions for flights.  We hope for more opportunities to collect images of pilot whales, sperm whales, false killer whales, and Bryde’s whales throughout HICEAS.

05_Leg1Map

HICEAS is designed to survey the entire Hawaii EEZ (light blue line), including the area of the original Papahānaumokuākea Marine National Monument (purple area) and the recent Monument expansion (green area) over 187 days. The red shading is a focus area around the main Hawaiian Islands. Leg 1 aboard the Sette included daytime effort from east of Hawai’i Island to south of Lisianski (white line) and included 46 cetacean sightings (see legend). The remainder of the HICEAS study area will be surveyed over the next six legs.

Cetacean sightings during the first leg of HICEAS aboard the Sette.

All told, during the first 28 days at sea aboard the Sette, we visually and acoustically surveyed 2,330 nmi of daytime trackline extending from east of Hawaiʻi Island to south of Lisianski in the northwestern Hawaiian Islands. Our visual team sighted 46 groups of cetaceans, while the acoustics team detected 129 vocal groups. Our seabird observers tallied 35 species during the effort, including 148 flocks of feeding seabirds, an important indicator of ocean productivity and ecosystem health. We recovered 3 DASBRs, and (sigh) spent a few days chasing DASBR ghosts–those that got away when their Iridium transmitters stopped telling us where they’d gone [this was likely due to unintended water leaks into the spar buoy (we’ve vanquished that gremlin, and still hope a charitable boater may find our wayward DASBRs and give us a call)]. We lent a hand to our monk seal and marine turtle colleagues with a brief stop at French Frigate Shoals to deliver fuel and supplies for another several weeks of their seal and turtle research on this remote atoll. We were supported by (in our opinion) the most capable crew and supportive command in the NOAA fleet. Apart from the Sette’s usual excellence, we were especially lucky to be supported by LCDR Emily Rose (aka Master Survey Tech) and Electronics Technician Patrick Trevethan who stepped in and kept our CTD operations running smoothly when our original Survey Tech had to leave the ship early. We were also fortunate on leg 1 to have sailed with an excellent NOAA Teacher at Sea, Staci Deschryver, who chronicled her adventures on HICEAS in a fantastic blog series.

The HICEAS adventure resumed August 8 on the Sette for leg 2 and was enhanced on August 17, when the Lasker began its journey west to join the HICEAS effort.  Both ships will continue surveying until September 5, when they will take a short break before departing again. Stay tuned to the HICEAS website for updates from both ships!

Sometimes there’s more to look at than animals. After dodging rain squalls, the visual team is rewarded with a beautiful rainbow. Photo credit: NOAA Fisheries/Adam Ü

All photos taken under research permit.

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

 

 

The final count: cruise for monitoring of effects of ocean and climate change in the Northwestern Hawaiian Islands completed

By Chip Young

Scientists from the PIFSC Coral Reef Ecosystem Division (CRED) recently completed a 17-day expedition to the Northwestern Hawaiian Islands, where they conducted coral reef monitoring surveys at Pearl and Hermes Atoll, Lisianski Island, and French Frigate Shoals. These 3 locations are part of the Papahānaumokuākea Marine National Monument and World Heritage Site, the third largest marine protected area on Earth and the largest conservation area in the United States.

This PIFSC research cruise (HA-13-05) aboard the NOAA Ship Hi`ialakai implemented a standardized set of methods for the measurement of fluctuations in the region’s coral reef ecosystems caused by global climate change. NOAA’s National Coral Reef Monitoring Plan (NCRMP) outlines the importance of monitoring changes in temperature and the chemical composition of ocean waters within which the coral reef ecosystems of the United States are found. Coral reefs are fragile biological systems that have been observed to live best in specific ranges of water temperatures and composition parameters. Changes in either of these ranges can cause a coral reef system to malfunction, through problematic processes that are familiar to much of the general public. Such processes, including coral bleaching (a result of increased ocean temperatures) and ocean acidification (a result of a drop in the ocean’s pH), affect the ability of corals and other reef organisms to calcify or “build their houses.” Other potential effects can occur, as well, such as shifts in biogeochemical cycles, shifts in species diversity, and changes in the ocean’s food web.

Jamison Gove and Chip Young of the PIFSC Coral Reef Ecosystem Division deploy oceanographic instrumentation on Sept. 13 at Lisianski Island as part of the recent research cruise to the Northwestern Hawaiian Islands. NOAA photo by Oliver Vetter

Jamison Gove and Chip Young of the PIFSC Coral Reef Ecosystem Division deploy oceanographic instrumentation on Sept. 13 at Lisianski Island as part of the recent research cruise to the Northwestern Hawaiian Islands. NOAA photo by Oliver Vetter

As part of the implementation of the NCRMP, CRED scientists on Sept. 3–19 deployed 16 arrays of temperature sensors along various reef systems, installing a total of 64 instruments at depths of 1–25 m. At its specific location on a reef, each sensor records the seawater temperature at the same time as other sensors, every 5 min, over a period of 3 years. The resulting product is a high-resolution picture of temperature variability of 16 different reef systems across space (across the archipelago and to a depth of 25 m) and time (3-year deployment of each sensor).

During the monitoring cruise earlier this month, 100 calcification accretion units (CAUs), like the one shown above, were installed in the Northwestern Hawaiian Islands by staff of the PIFSC Coral Reef Ecosystem Division. CAUs are used to measure not only net reef calcification rates but also species-specific recruitment rates and the percent cover of corals, crustose coralline algae, and fleshy algae. NOAA photo

During the monitoring cruise earlier this month, 100 calcification accretion units (CAUs), like the one shown above, were installed in the Northwestern Hawaiian Islands by staff of the PIFSC Coral Reef Ecosystem Division. CAUs are used to measure not only net reef calcification rates but also species-specific recruitment rates and the percent cover of corals, crustose coralline algae, and fleshy algae. NOAA photo

CRED scientists and partners also collected samples of seawater for chemical analysis, conducted hydrocasts with a conductivity-temperature-depth (CTD) instrument, and deployed installations designed to measure specific biological activities that can be affected by changes in the pH of a reef’s waters. Settling plates, known as calcification accretion units (CAUs), are used to measure net reef calcification rates, species-specific recruitment rates, and the percent cover of corals, crustose coralline algae, and fleshy algae. Bioerosion monitoring units (BMUs) are made up of precisely measured pieces of calcium carbonate, the material that makes up the skeletal structure of corals, and will provide a value for how much biological removal of reef structure is naturally present along the reef. Autonomous reef monitoring structures (ARMS) essentially act as “hotels” for cryptic biota living within the matrix of a reef ecosystem and provide a standard method for evaluation of the existing community of sessile and mobile organisms found on a reef.

Including work conducted during this cruise and the earlier PIFSC cruise SE-13-05 to Kure Atoll in July, CRED scientists have installed 100 CAUs, 50 BMUs, and 24 ARMS throughout the Northwestern Hawaiian Islands this year. Because monitoring activities associated with NCRMP are conducted on a triennial basis, CRED will return to these islands in 2016. At that time, researchers will retrieve and replace all instruments. NCRMP is a long-term project, and the goal of this work is to measure change over time. The results from this ongoing project will be available to help the managers of these remote islands monitor, evaluate, and predict the ecological effects of global climate change on the reefs of the Papahānaumokuākea Marine National Monument.

Reef monitoring cruise in the main Hawaiian Islands completed: preliminary results from fish surveys

Last Friday afternoon, Aug. 23, the NOAA Ship Hi`ialakai returned to Honolulu from a Pacific Reef Assessment and Monitoring Program (Pacific RAMP) cruise (HA-13-04) during which staff of the PIFSC Coral Reef Ecosystem Division (CRED) and partners conducted surveys of reef fish assemblages and benthic communities at the islands of Hawai`i, Lāna`i, Kaua`i, Maui, Moloka`i, Ni`ihau, and O`ahu and deployed instruments and collected water samples to monitor effects of climate change and ocean acidification on the coral reef ecosystems of those islands.

Over the course of this expedition, which began on Aug. 1, CRED staff and partners accomplished the following field activities: 1031 dives, reef fish surveys at 237 Rapid Ecological Assessments (REA) sites, benthic surveys at 104 REA sites, collections of 30 water samples and 42 benthic samples for analysis of microbial communities, retrieval of 18 and deployment of 12 autonomous reef monitoring structures, installation of 120 calcification accretion units and 30 bioerosion monitoring units, recovery of 4 ecological acoustic recorders, retrieval of 18 and deployment of 32 subsurface temperature recorders, and completion of 71 shallow-water conductivity, temperature, and depth (CTD) casts and 69 deepwater (shipboard) CTD casts. Additional water samples were collected for analyses of dissolved inorganic carbon, total alkalinity, and salinity.

Preliminary results from the surveys of reef fishes conducted by scuba divers at depths of 0–30 m during the PIFSC cruise HA-13-04 are provided in the fish monitoring brief below.

Pacific Reef Assessment and Monitoring Program
Fish monitoring brief: main Hawaiian Islands 2013

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 status report.

Sampling effort

  • Ecological monitoring took place in main Hawaiian Islands from August 2 2013 to August 22 2013.
  • Data were collected at 237 Rapid Ecological Assessments (REA) sites. Surveys were conducted at Hawai`i (n=58), Kaua`i (n=37), Lāna`i (n=29), Maui (n=34), Moloka`i (n=39), Ni`ihau (n=26) and O`ahu (n=14).
  • At each REA site, the fish assemblage was surveyed by underwater visual census and the benthic community was assessed.

Overview of data collected

Figure 1. Mean total fish biomass (g m–2)  at sites surveyed.

Figure 1. Mean total fish biomass (g m–2) 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 (±1 standard error). Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 4. Mean fish biomass per size class (±1 standard error). Fish measured by total length (TL) in centimeters (cm).

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 sample design

Locations of REA sites 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, eshy 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

Follow this link for a PDF version of this main Hawaiian Islands 2013 fish monitoring brief.

Mission at Kure Atoll focused on study of effects of climate change and ocean acidification

By Chip Young

To be working in Honolulu one day and then be scuba diving to conduct coral reef research in one of the world’s most remote atolls by the next morning is a surreal experience. Such a swift change of pace was the situation recently for 4 researchers from the PIFSC Coral Reef Ecosystem Division (CRED). On July 11, Jamison Gove, Noah Pomeroy, Kerry Reardon, and Chip Young joined the PIFSC cruise SE-13-05 aboard the NOAA Ship Oscar Elton Sette at Midway Atoll after an evening flight. That same night, the ship, which also supported deployment of monk seal camps for the PIFSC Protected Species Division during this cruise, transited to Kure Atoll, the northernmost atoll in the Pacific Ocean island chain known as the Northwestern Hawaiian Islands. Located more than 2000 km from Honolulu, Kure Atoll is an amazing natural environment and part of the Papahānaumokuākea Marine National Monument, established in 2006 and named a World Heritage Site in 2010.

Chip Young installs a subsurface temperature recorder at Kure Atoll on July 16 with an ulua, or giant trevally (Caranx ignobilis), in the foreground. NOAA photo by Noah Pomeroy

Chip Young installs a subsurface temperature recorder at Kure Atoll on July 16 with an ulua, or giant trevally (Caranx ignobilis), in the foreground. NOAA photo by Noah Pomeroy

Kure Atoll was formed roughly 35 million years ago when the seafloor beneath it was located over the same volcanic hotspot upon which the island of Hawai`i currently sits. A vestige of what was once a volcanic island, Kure Atoll now exists as a collection of very small, low-lying islands that make up less than 1 km2 of land and are encircled by an expansive fringing coral reef environment that includes 167 km2 of banks with depths less than 100 m. It was on these reefs that the CRED researchers conducted scuba dives on July 12–14 to establish long-term survey sites that will enable scientists to monitor the health of Kure Atoll’s reefs into the future.

The goal of this mission at Kure Atoll was to conduct the initial surveys of a broad, nationwide monitoring strategy that was established in 2012 by NOAA’s Coral Reef Conservation Program and is known as the National Coral Reef Monitoring Plan. This plan institutes survey methods that allow for the measurement of how the coral reef ecosystems of the United States change over time and incorporates most of the methods from CRED’s Pacific Reef Assessment and Monitoring Program that have been used to monitor the coral reef ecosystems of the U.S. Pacific islands and atolls since 2001.

During this expedition, the researchers focused on issues of global climate change through investigation of water chemistry, water temperature, reef calcification rates, and biodiversity of the small organisms living within reefs (cryptobiota). At Kure Atoll, scientists collected water samples for analysis of carbonate chemistry, including dissolved inorganic carbon, total alkalinity, salinity, and chlorophyll-a; retrieved and deployed oceanographic instruments, such as subsurface temperature recorders (STRs), and biological installations, such as calcification accretion units; and completed conductivity, temperature, and depth casts. The use of each method offers insight into the effects of global climate change and ocean acidification on the coral reefs of Kure Atoll, and after a long-term data set is compiled for these reefs, NOAA scientists will be able to identify the factors that influence ecosystem change and help managers of U.S. reef environments understand the processes that affect their areas of responsibility. Similar work is planned for other islands in the Northwestern Hawaiian Islands in September.

In addition to work at Kure Atoll during this cruise, scientists also retrieved and deployed STRs and retrieved other oceanographic instruments at Pearl and Hermes Atoll and retrieved STRs from Laysan Island.