Coral reef monitoring in the Mariana Archipelago: preliminary results from visual surveys of fishes and benthic habitats

By Kathryn Dennis and Bernardo Vargas-Ángel

The PIFSC cruise HA-14-01 officially concluded yesterday, Monday, June 2, when the NOAA Ship Hi`ialakai arrived back at Ford Island, Pearl Harbor, from Saipan. During this expedition, which began on March 5, scientists from the PIFSC Coral Reef Ecosystem Division (CRED) and partners conducted ecological surveys, collected water samples, and deployed monitoring instruments and platforms at Wake Island and in the Mariana Archipelago as part of the CRED-led Pacific Reef Assessment and Monitoring Program (Pacific RAMP). As a part of the National Coral Reef Monitoring Plan of NOAA’s Coral Reef Monitoring Program, researchers established climate monitoring stations at 4 islands in the Mariana Archipelago and at Wake Island, where integrated activities provide for long-term collection of data on ocean temperature, chemical composition, benthic cover, calcification, bioerosion, and biodiversity to monitor the effects of climate change and ocean acidification.

The volcano on the island of Pagan emits plumes of gas and steam on the evening of April 20, as seen in this photo taken during the PIFSC cruise HA-14-01. NOAA photo

The volcano on the island of Pagan emits plumes of gas and steam on the evening of April 20, as seen in this photo taken during the PIFSC cruise HA-14-01. NOAA photo

From March 25 to May 6, during Legs II and III and part of Leg I of this latest research cruise at Guam and the Commonwealth of the Northern Mariana Islands (CNMI), CRED scientists and partners completed 100 broad-scale towed-diver surveys, covering more than 220 km of coastline and, at Rapid Ecological Assessment (REA) sites, conducted 329 fish surveys and 158 benthic surveys. Members of the CRED Climate and Ocean Change Team installed 15 climate monitoring stations around Guam, Saipan, Pagan, and Maug, deploying 15 subsurface temperature recorders (STRs), 55 calcification accretion units (CAUs), 45 autonomous reef monitoring structures (ARMS), and 75 bioersion monitoring units (BMUs)—in addition to installations of 70 CAUs at supplementary monitoring sites and 55 STRs at strategic locales associated with climate monitoring stations and long-term (>9 years) time series. For a summary of activities conducted and preliminary results from REA surveys at Wake Island during Leg I, go to the previous blog post published on April 10.

A cursory review (prior to the data being fully analyzed) did not reveal any observations of notable changes in the structure of the fish and benthic communities, in comparison with survey results from the previous Pacific RAMP cruise in the Mariana Archipelago in 2011, at Rota, Aguijan, Tinian, Saipan, Sarigan, Guguan, Alamagan, Pagan, Asuncion, Maug, and Farallon de Pajaros in the CNMI or at Guam are reported at this time. However, unusual cold-water temperatures (~17°C) were experienced at Asuncion, Maug, and Farallon de Pajaros, as was volcanic activity that originated mainly from Ahyi Seamount located nearly 18 km southeast of Farallon de Pajaros.

Preliminary results from the surveys at REA sites of fishes and benthic habitat conducted at depths of 0–30 m by scuba divers from the CRED Fish Ecology Team during the PIFSC cruise HA-14-01 are provided in the fish monitoring brief below. The islands on the Mariana Arc can be divided into 2 groups: the old southern islands and the young, volcanic northern islands. The summary below also was published on May 23 (and is available for download) as 2 separate 2-page PIFSC Data Reports, one for the southern islands of this archipelago and the other for the northern islands.

Pacific Reef Assessment and Monitoring Program
Fish monitoring brief: Mariana Archipelago 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 in the southern islands

  • Ecological monitoring took place in the southern Mariana Archipelago from March 25 2014 to May 07 2014.
  • Data were collected at 178 sites. Surveys were con- ducted at Saipan (n=11), Tinian (n=19), Aguijan (n=10), Rota (n=28), and Guam (n=73).
  • At each site, the fish assemblage was surveyed by underwater visual census and the benthic community was assessed.

Sampling effort in the northern islands

  • Ecological monitoring took place in the northern Mariana Archipelago from April 19 2014 to May 06 2014.
  • Data were collected at 148 sites. Surveys were conducted at Farallon de Pajaros (FDP) (n=11), Maug (n=40), Asuncion (n=21), Pagan (n=43), Alamagan (n=11), Guguan (n=11), and Sarigan (n=11).
  • At each 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 at sites surveyed in the southern islands.

Figure 1. Mean total fish biomass at sites surveyed in the southern islands.

Figure 2. Mean total fish biomass at sites surveyed in the northern islands.

Figure 2. Mean total fish biomass at sites surveyed in the northern islands.

Figure 3. Mean hard coral cover at sites surveyed in the southern islands.

Figure 3. Mean hard coral cover at sites surveyed in the southern islands.

Figure 4. Mean hard coral cover at sites surveyed in the northern islands.

Figure 4. Mean hard coral cover at sites surveyed in the northern islands.

Preliminary results for fish biomass also are presented by consumer group and size class. 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 5. Mean consumer group fish biomass (± standard error) at sites surveyed in the southern islands. Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 5. Mean fish biomass (± standard error) by consumer group at sites surveyed in the southern islands. Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 6. Mean consumer group fish biomass (± standard error) at sites surveyed in the northern islands. Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 6. Mean fish biomass (± standard error) by consumer group at sites surveyed in the northern islands. Primary consumers are herbivores and detritivores, and secondary consumers are omnivores and invertivores.

Figure 7. Mean fish biomass per size class (± standard error) at sites surveyed in the southern islands. Fish measured by total length (TL) in centimeters (cm).

Figure 7. Mean fish biomass per size class (± standard error) at sites surveyed in the southern islands. Fish measured by total length (TL) in centimeters (cm).

Figure 8. Mean fish biomass per size class (± standard error) at sites surveyed in the northern islands. Fish measured by total length (TL) in centimeters (cm).

Figure 8. Mean fish biomass per size class (± standard error) at sites surveyed in the northern islands. 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. 9). 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 generally will be pooled to improve island-scale estimates.

Each diver also conducts a rapid visual assessment of reef composition, by estimating the percent 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 line at each site that are archived to allow for future analysis.

Figure 9. Method used to monitor fish assemblage and benthic communities at the Rapid Ecological Assessment (REA) sites.

Figure 9. Method used to monitor fish assemblage and benthic communities at Rapid Ecological Assessment (REA) sites.

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: 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

 

To download a PDF file of PIFSC Data Report DR-14-009, the fish monitoring brief for the southern islands of the Mariana Archipelago, click here.

To download a PDF file of PIFSC Data Report DR-14-010, the fish monitoring brief for the northern islands of the Mariana Archipelago, click here.

 

Update from the Mariana Archipelago: monitoring cruise completes work in the southern islands

By Bernardo Vargas-Ángel
The NOAA Ship Hi`ialakai, seen off the coast of Anatahan, a northern island in the Commonwealth of the Northern Mariana Islands, during a previous monitoring cruise in the Mariana Archipelago in May 2009. NOAA photo by Bernardo Vargas-Ángel

The NOAA Ship Hi`ialakai, seen off the coast of Anatahan, a northern island in the Commonwealth of the Northern Mariana Islands, from a small boat during a previous monitoring cruise in the Mariana Archipelago in May 2009. NOAA photo by Bernardo Vargas-Ángel

On April 17, the NOAA Ship Hi`ialakai departed Saipan Harbor and began Leg III of the PIFSC cruise HA-14-01 with a few more days of monitoring operations around Saipan before transiting to the island of Sarigan. With work essentially complete in the southern islands of the Mariana Archipelago, the Hi`ialakai had been in port in Saipan Harbor for a short, 3-day pause between legs of this Pacific Reef Assessment and Monitoring Program (Pacific RAMP) expedition. Activities to monitor coral reef ecosystems of the Commonwealth of the Northern Mariana Islands (CNMI) began on April 5 during Leg II of this cruise and work around Guam took place on March 25–April 4, primarily during Leg I. Led by the PIFSC Coral Reef Ecosystem Division (CRED), this mission marks the 6th monitoring cruise in Guam and the CNMI by staff from PIFSC and partner agencies since 2003.

Around Guam, Rota, Aguijan, Tinian, and Saipan Islands, CRED scientists on March 25–April 18 conducted ecosystem surveys of fishes, benthic and coral communities, and microbes and deployed oceanographic instruments and biological installations. During Leg III, which is expected to conclude on May 6, CRED staff will conduct small-boat operations for coral reef ecosystem monitoring at the following northern islands and banks: Sarigan, Zealandia Bank, Guguan, Alamagan, Pagan, Agrihan, Asuncion, Maug, Supply Reef, and Farallon de Pajaros (or Uracas).

On a reef off the coast of Rota Island, divers conduct belt-transect surveys of the benthos on April 8. NOAA photo by Bernardo Vargas-Ángel

On a reef off the coast of Rota Island, divers conduct a belt-transect survey of the benthos on April 8 during the PIFSC cruise HA-14-01, the 6th expedition in the Marina Archipelago since 2003 for the Pacific Reef Assessment and Monitoring Program, which is led by the PIFSC Coral Reef Ecosystem Division. NOAA photo by Bernardo Vargas-Ángel

A diver on April 13 collects digital images of reef benthos along a transect at a Climate Monitoring Station off the cost of Saipan. NOAA photo

A diver on April 13 collects digital still photographs of the reef benthos along a transect at a Climate Monitoring Station off the cost of Saipan. Such benthic images can be analyzed to characterize benthic habitat and estimate percent cover of key functional groups. NOAA photo

At Rapid Ecological Assessment (REA) sites, surveys for reef fishes document species richness, abundance, and sizes, and surveys of benthic and coral communities study the percent composition of bottom-dwelling organisms in addition to the densities, sizes, and health conditions of coral colonies. During broad-scale towed-diver surveys, divers record observational data on large-bodied fishes (>50 cm total length), percent composition of the seafloor, coral stress, and conspicuous invertebrates. Studies of microbial communities document the diversity and abundance of bacteria and viruses and their interactions with coral reefs.

This mission also includes studies of the diversity of cryptic invertebrates; collection of data on water temperature, salinity, carbonate chemistry, and other physical characteristics of coral reef environments; and assessment of the potential early effects of ocean acidification on cryptobiota (e.g., small, hidden organisms) and the rates of reef carbonate deposition and coral calcification.

Researchers of the PIFSC Coral Reef Ecosystem Division use trays, like the one in this photo taken on April 13, to sort the cryptic reef invertebrates that they collect from autonomous reef monitoring structures (ARMS) retrieved during this current cruise from the nearshore locations where they had been deployed in 2011 during the previous Pacific Reef Assessment and Monitoring Program expedition in the Mariana Archipelago. NOAA photo

Researchers of the PIFSC Coral Reef Ecosystem Division on April 13 use this tray and others to sort the cryptic reef invertebrates that they collect from the autonomous reef monitoring structures (ARMS) retrieved during this current cruise from the nearshore locations where they had been deployed in 2011 during the previous Pacific Reef Assessment and Monitoring Program expedition in the Mariana Archipelago. NOAA photo

Thus far across the 5 southern Mariana Islands, including work on April 17, CRED researchers during this cruise have completed 66 towed-diver surveys along a combined 130 km of coastline and, at REA sites, 153 fish surveys and 62 benthic surveys. The instrumentation team deployed 4 Climate Monitoring Stations around Guam and 3 stations around Saipan, with each station containing arrays of subsurface temperature recorders (STRs), calcification accretion units (CAUs), autonomous reef monitoring structures (ARMS), and bioersion monitoring units (BMUs). Overall, no notable changes in the structure of the fish and benthic communities can be reported at this time for the areas surveyed at Guam or in the southern CNMI, in comparison to survey results from the previous cruise in this region in 2011. Additionally, no widespread coral bleaching or outbreaks of coral diseases or corallivorous crown-of-thorns seastars (Acanthaster planci) were observed.

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.

Visit to Johnston Atoll Wildlife Refuge: PIFSC SE-13-07 “Deep -7” Bottomfish research expedition blog

We visited Johnston Atoll today via small boat launches from the NOAA Ship Oscar Elton Sette. The story of the atoll is long and varied and it has had multiple uses throughout its history. At the end of WWII Johnston Atoll was designated a site for one of the United States’ nuclear testing programs. Up until 1962, high-altitude nuclear testing was carried out at Johnston Atoll. Johnston Atoll was also a site for stockpiling chemical weapons which were incinerated in the Johnston Atoll Chemical Agent Disposal System which was decommissioned in 2004. Almost all of Johnston Island’s infrastructure had been removed by 2005, and all personnel left the atoll, including refuge staff.

See these external sites for more information about Johnston Atoll:
http://www.fws.gov/johnstonisland/
http://www.doi.gov/oia/islands/johnston.cfm
http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Johnston_Atoll.html
http://www.cma.army.mil/johnston.aspx

On approach to Johnston Atoll.  In the background is one of the leftover buildings from when this was a bustling US military base

On approach to Johnston Atoll. In the background is one of the leftover buildings from when this was a bustling US military base

One of the most amazing sites as you approach the island is the amazing coral reefs surrounding the island. There are numerous species of coral at Johnston Atoll with the most conspicuous species being the giant table coral (Acropora cytherea). See previous bottomfish research expedition post: http://bit.ly/16lqv6R

The 5 U.S. Fish & Wildlife Service (USFWS) staff were very happy to receive us and to accept our gifts of fresh produce. The USFWS staff were very hospitable and upon our arrival provided everyone with homemade leis.

The U.S. Fish and Wildlife Service staff presenting us with homemade leis

The U.S. Fish and Wildlife Service staff presenting us with homemade leis

Preparing for a tour of the island

Preparing for a tour of the island

The USFWS staff gave us a tour of the island and showed us some of the more interesting aspects of the atoll. They also offered us bikes to use for riding around the island. This short respite was very welcome and it felt great to step on dry land and stretch the legs. The atoll has an interesting mix of natural and manmade curiosities as you tour around. One of the first things you notice is the large colonies of birds, which is to be expected as Johnston Atoll National Wildlife Refuge manages 14 species of breeding sea birds and 5 species of wintering shorebirds see external link: http://www.fws.gov/refuges/profiles/index.cfm?id=12515 for more details.

The yellow crazy ants (Anoplolepis gracilipes) super-colonies had us all intrigued. These ants spray formic acid into the eyes of their prey, and then while the animal is blind overcome it with numbers. We were warned about these prior to our visit and had to take measure to ensure we did not take any hitchhikers back with us. Presently the USFWS has a group on the island eradicating this menace and hopefully this will be accomplished soon.

See external links for more information on the yellow crazy ants: (http://news.bbc.co.uk/2/hi/asia-pacific/2807289.stm; http://www.ncbi.nlm.nih.gov/pubmed/21396065)

The island is dotted with ironwood and palm trees planted by the previous inhabitants interspersed with remnant cement foundations that all are indicators of the previous incarnation of the island as a busy military base.

The crew and scientists were back aboard NOAA Ship Oscar Elton Sette by 1930h and the ship began its transit back to Ford Island, Honolulu.

Shark Encounters: PIFSC SE-13-07 “Deep -7” Bottomfish research expedition blog

Shark interactions

When we first arrived in the Pacific Remote Islands Marine National Monument waters off Johnston Atoll we started plotting bottomfish sampling locations using topography, currents and the EK-60 fish finder to identify areas of interest. However this was altered during the field work because we encountered a lot of sharks during our fishing efforts. We later decided to target depth features with less fish abundance so we would have a higher probability of obtaining our samples without shark interference. See previous bottomfish research expedition post: http://bit.ly/17RGrdg

Submerged Go-Pro shots of sharks believed to be Galapagos.  Photo taken from NOAA Ship Oscar Elton Sette in waters around Johnston Atoll gave evidence of the increased shark numbers interacting with our bottomfish sampling.

Submerged Go-Pro shots of sharks believed to be Galapagos. Photo taken from NOAA Ship Oscar Elton Sette in waters around Johnston Atoll gave evidence of the increased shark numbers interacting with our bottomfish sampling.

The sharks appeared to be Galapagos sharks based on surface sightings and “Go-Pro” camera video shots taken underwater from a submerged pole over the NOAA Ship Oscar Elton Sette’s side. Once we are back in Honolulu we will upload the videos to this blog for your viewing. We have some amazing footage that provided a huge surprise on the actual number of sharks present under the boat. One video showed at least 15 sharks circling at one time.

During one day of bottomfish sampling from the NOAA Ship Oscar Elton Sette we were operating on a one drop per station method. Typically we could get one drop down and recover fish but on the second drop the sharks were ready for us and either attacked our fishing line deep during retrieval or at/near the surface. Three Galapagos sharks completely devoured a hapu’upu’u that we brought to the surface; excellent “Go-Pro” video was taken of this event. The small boats were also plagued by shark activities.

Hapu'upu'u dinner!  This is a still shot from a video Justin Kantor shot of three Galapagos sharks completely devouring one of our samples.  Obviously the hapu'upu'u's facial features say it all.

Hapu’upu’u dinner! This is a still shot from a video Justin Kantor shot of three Galapagos sharks completely devouring one of our samples. Obviously the hapu’upu’u’s facial features say it all.

Galapagos sharks fight over the remains of the hapu'upu'u

Galapagos sharks fight over the remains of the hapu’upu’u

Shark avoidance maneuver on the small boats

What the?  Eddie Ebisui III is not too happy with the percentage of "taxes" the Galapagos sharks ("the taxman") are taking.  The sharks bite the entire bodes clean off.

What the? Eddie Ebisui III is not too happy with the percentage of “taxes” the Galapagos sharks (“the taxman”) are taking. The sharks bite the entire bodes clean off.

The small boat crew also had their hands full with the over-exuberant sharks. To avoid the problem of losing parts or all of the fish to the sharks, the small boat crew came up with a “shark avoidance maneuver”. Jamie Barlow explained that once sharks were spotted while reeling in a desirable bottomfish (determined by how the line feels during the bite), the small boat would have to maneuver to avoid loss of the sample. This could be accomplished either by speeding away with a high probability of losing the sample (fish busting the leader or tearing away) or going slow and losing the sample to the shark. To avoid either of these undesirable outcomes they considered several factors when determining actions to be taken on the small boat for saving the fish.

Every situation was different and the coxswain had to mitigate the risks and factor in these variables:

1. What is the load (weight) on the rod and reel (how big, how many)

2. Consideration of running the small boat down seas so the rod does not jerk the fish and release itself from the hole the hook would make in the fish’s jaw.

3. Be aware of the location of the sun glare (reflection of the sun off the water) and finish the maneuver so the small boat crew can see the sharks for the last critical 30 seconds of recovery

4. Consider heading to deeper waters where typically there was less shark abundance

5. How aggressive are the sharks?

6. Pull the line with the fish rapidly and safely into the boat without inviting the shark into boat as well

7. Whoever is pulling the line is experienced enough so that if the shark does grab the fish, they will hold that line firmly to bust the leader and prevent gear and hooks to be pulled backward by the powerful fish.

While calculating these variables, Jamie Barlow would conduct this maneuver as a spiraling left turn. Varying angles and speeds were balanced while being mindful of keeping the line away from the prop and bringing the fish coming out at an angle and a speed that prevents the shark from grabbing the fish. This was a tricky maneuver, but it worked for about 3-5 times, after which, the sharks wised up. The sharks had watched enough fish scoot passed them to learn that a bold burst of ambush speed would reward the natural predator with a tasty opakapaka or onaga. And once they got that bold the fishermen would have to tuck their tails between their legs and run a mile to a new spot and start the “small boat shark maneuver” all over again. See next bottomfish research expedition post: http://bit.ly/15VFlU8

In search of the elusive bottomfish: PIFSC SE-13-07 “Deep -7” Bottomfish research expedition blog

Searching out Deep-7 bottomfish

Extensive effort was required to collect a minimum of 30, and maximum of 50, fin-clip tissue samples from bottomfish in the Johnston Atoll area to conduct DNA analyses. Proposing the collection of 30 fin clips is very different from actually obtaining them, especially in an area where very little is known about bottomfish behavior. See previous bottomfish research expedition post: http://bit.ly/1cI479t

Bottomfish sampling team from left to right Meagan Sundberg, Jamie Barlow, Mills Dunlap, Eddie Ebisui III

Bottomfish sampling team from left to right Meagan Sundberg, Jamie Barlow, Mills Dunlap, Eddie Ebisui III

Our bottom fishing expert, Eddie Ebisui III and our Chief Scientist Bob Humphreys were tasked with providing the best spots for collecting the samples. The night before fishing, they would look at the weather for the following day to determine the area most conducive for fishing and away from bad weather. By deciding the night before it allowed the time for the ship to transit through the night to the desired location for scouting.

Once over the desired location, a course would be plotted for the ship to take that covers the targeted depth ranges of the Deep-7 bottomfish species we were seeking. The ship will survey for topography, currents and use an EK-60 fish finder to identify areas of interest. The depth ranges were determined from knowledge we had from Hawaiian waters and also by continually adapting our fishing according to our catch data in the Johnston Atoll waters of the Pacific Remote Islands Marine National Monument. Certain species look for bottom structure and also specific current speeds and direction. For example, hapu’upu’u live in a depth range of 100-130 fathoms and since they are ambush feeders, they like rocky structures with caves and crevices to help them to eat. They are solitary and are spread out over larger spatial areas so requires continuous moving to catch them. gindai and yellowtail kalekale are found over the entire depth range while onaga were typically found around 120-140 fathoms and had the narrowest depth band of each of the Deep-7 species. Once locations were identified they were marked and the GPS coordinates were passed onto the small boats

The depth distribution of the bottomfish seemed shifted toward deeper depths at Johnston Atoll compared to the Main Hawaiian Islands. Louise Giuseffi plotted depth ranges for 8 bottomfish species that included the almaco jack (Seriola riviolani), black ulua, ehu gindai, hapu’upu’u, lehi, onaga, and opakapaka and all had similar deep distributions between 115-140 fathoms. The most abundant species that appeared at all depths was the yellowtail kalekale while the two principal species of jacks encountered (Carangoides orthogrammus and Caranx lugubris) were encountered at the shallower depth from 85-110 fathoms. The bottomfish habitat at Johnston Atoll is likely highly influenced by the steep topography of the bottom.

Our efforts resulted in a cumulative number of fin clip samples obtained for the snapper/grouper complex:

Our efforts resulted in a cumulative number of fin clip samples obtained for the snapper/grouper complex:

Our efforts resulted in a cumulative number of fin clip samples obtained for the snapper/grouper complex:

Eddie Ebisui III and Jamie  Barlow displaying the catch of the day.  While catch and release was the primary goal fish had to be kept when shark interactions occurred.

Eddie Ebisui III and Jamie Barlow displaying the catch of the day. While catch and release was the primary goal fish had to be kept when shark interactions occurred.

We have now achieved our minimum sample sizes (n=30) for 5 species (onaga, opakapaka, hapu’upu’u, gindai, and yellowtail kalekale) and optimum sample size (n=50) for opakapaka, gindai, and yellowtail kalekale.

Scientists and crew on the NOAA Ship Oscar Elton Sette preparing for the days operations.  From front to back: Tommy Knowles, Ray Storms, Stephanie Koes (The Commanding Officer of the Oscar Elton Sette), Eric Mooney, Eric Breuer, and Justin Kantor.

Scientists and crew on the NOAA Ship Oscar Elton Sette preparing for the days operations. From front to back: Tommy Knowles, Ray Storms, Stephanie Koes (The Commanding Officer of the Oscar Elton Sette), Eric Mooney, Eric Breuer, and Justin Kantor.