White Caps, Painted Dolphins, and Sperm Whales Galore!

by Marie C. Hill, Andrea R. Bendlin, Allan D. Ligon, and Adam Ü

After having to skip our surveys off Saipan last year because of the damage from Typhoon Soudelor, we were happy to return during 7-18 May 2016 to continue our ongoing study of cetaceans in the Marianas.  It is good to see and hear that Saipan is recovering.  Soudelor was the second strongest typhoon to develop in the northern hemisphere in 2015.  On 2 August 2015, it hit Saipan directly and devastated the island.  Homes and businesses were destroyed and others were damaged and without power for months.

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Figure 1: Two of four rough-toothed dolphins photographed together during 2013, 2014, and 2016 (photo credit: Marie Hill and Daniel Webster).

We had a bit of a slow start to our surveys because the winds and swells were up. Despite the rough conditions, we did find one of our favorite species, rough-toothed dolphins (Steno bredanensis), near Chalan Kanoa Reef, off the west side of Saipan.  Their crocodile shaped heads and their mottled bodies make them one of the most unusual looking dolphins alive, and some of the individuals present during this encounter are exceptionally mottled (Figure 1).  They look hand-painted.  What is also interesting about the Steno we encountered is that four of the five belong to our photo-identification catalog of six individuals.   We have seen them together in July 2013 and April 2014 off Aguijan and in July 2013 off Saipan, suggesting that they are resident to this area.  The fifth individual was a juvenile that may have been born in 2014.

Other strange looking cetaceans that we encountered during our surveys off Saipan were sperm whales (Physeter macrocephalus) (Figure 2).  They are the only cetacean species with their blow hole at the tip of their rostrum and it is canted to the left.  This characteristic can make them easily identifiable from a distance because their blow is angled.

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Figure 2: Sperm whales have a blow hole that is at the tip of their rostrum and is angled to the left (A), which makes their blows angled (B) (photo credit: Marie Hill and Adam Ü).

We encountered sperm whales on two separate days.  Some of the same individuals were present during both sightings.  We are able to identify them, primarily from their flukes but in some cases can recognize them from dorsal hump and body characteristics, such as scars.  Since 2010, we have encountered sperm whales five times.  In addition to our two encounters this year, we have seen sperm whales off Guam and Saipan in 2010 and off Saipan in 2013.  After doing some preliminary comparisons with fluke photos taken off Guam and Saipan in 2010 and those we took this year, we found two matches.  Both individuals were photographed off Guam 18 February 2010 and during both 2016 sightings (Figure 3). One of the individuals is missing its left fluke.  We collected a small tissue (or biopsy) sample from it, as well as five other individuals during our 2016 encounters, for future genetic analyses.

Figure 3: Re-sights of two individuals between Guam (February 2010) and Saipan (May 2016) (photo credit: Adam Ü and Marie Hill).

Figure 3: Re-sights of two individuals between Guam (February 2010) and Saipan (May 2016) (photo credit: Adam Ü and Marie Hill).

During the sperm whale encounter on 17 May 2016, we deployed a satellite tag on an individual, so that we can learn more about sperm whale movements in this area.  Between 17 and 23 May it traveled north and south offshore of Saipan and Tinian’s west sides (Figure 4). On 23 May, it was located approximately 37km WNW of Saipan’s NW tip.

In addition to rough-toothed dolphins and sperm whales, we encountered bottlenose dolphins (Tursiops truncatus) and spinner dolphins (Stenella longirostris) off Saipan.  Next, we head to Rota to conduct surveys during 21-25 May.

Figure 4: Track of a satellite tag (ID 141712) attached to a sperm whale off Saipan on 17 May 2016.

Figure 4: Track of a satellite tag (ID 141712) attached to a sperm whale off Saipan on 17 May 2016.

All survey operations including satellite tagging, photo-id, and biopsy sampling are conducted under NMFS permit 15240. Funding was provided by the NOAA Fisheries and the Commander U.S. Pacific Fleet. We would like to thank the vessel owners, captains, and crew of the Sea Hunter and the Regulator; the CNMI DFW, the CNMI NOAA Fisheries field office, and all of our volunteers during the surveys.

 

Posted in Protected Species | Tagged , , , , , , , , , , , , , ,

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.

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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.
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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

 
Posted in coral reef ecosystem | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

How Does Energy Reach the Top of the Food Web?

A paper coauthored by PIFSC scientists looks at how energy makes its way to the top of the central North Pacific food web. The scientists used information on what marine organisms across the food web eat to build a food web model, diagrammed below. This model shows how energy produced by phytoplankton moves up through the food web, all the way to apex predators like tuna, billfish, and sharks. Results from this study deepen our understanding of how energy reaches commercially important species such as bigeye tuna and swordfish.

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Schematic model of the central North Pacific food web used in this study (from Choy et al. 2016)

Ecosystem models are one tool scientists use to study the food web. PIFSC scientists used an ecosystem model to improve their understanding of the middle of the food web, which is occupied by small organisms called micronekton. Micronekton are 2 – 10 cm in length, small enough to fit in the palm of your hand. They include marine animals like small fish, squid, crustaceans, and jellyfish. These animals are a critical part of the food web; they link energy produced at the base of the food web to apex predators at the top of the food web. Yet, compared to the top and bottom of the food web, little is known about these mid-trophic micronekton. They’re challenging to study for two main reasons. One, they live throughout the water column at depths ranging from the ocean’s surface to the ocean floor. Two, they’re pretty good at avoiding the nets scientists use to capture them.

This modeling study showed that some types of micronekton play a bigger role in the food web than others. Much of the energy that reaches apex predators flows through micronekton crustaceans and mollusks – organisms like the shrimp and squid shown here. Mid-trophic fish and jellyfish, on the other hand, transfer comparatively little energy to the top of the food web.

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Micronekton crustaceans with a 6-inch ruler for scale

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Micronekton mollusks with a 6-inch ruler for scale

Understanding how energy flows through the food web, and which organisms transfer the most energy, helps both scientists and fishery managers understand how apex predators may be impacted by future ecosystem change. This knowledge also highlights areas for future research. For example, there’s currently little known about how crustaceans and mollusks in the central North Pacific may be impacted by ocean acidification. Learning how important these organisms are in the food web underscores the need for investigating questions like this.

You can read more about micronekton and their role in the central North Pacific food web here: http://www.int-res.com/articles/meps_oa/m549p009.pdf

Posted in Ecosystems and Oceanography

SE16-02: Re-Breather diving in Samoa; counting fish without bubbles

by Jamie Barlow

Team Redundant” is what we proudly call ourselves; we are the re-breather team on the R/V Steel Toe and silently dive with the goal to count and size reef fish.

Figure 1: Ray Boland and Tate Wester pose for a picture; all gear up, cameras in hand, and in moments will roll out of the boat to start their reef fish survey.

Figure 1: Ray Boland (left) and Tate Wester (right) pose for a picture; all gear up, cameras in hand, and in moments will roll out of the boat to start their reef fish survey.

For the next couple of weeks PIFSC staff and partner agencies will be working off of the NOAA Ship Oscar Elton Sette in the American Samoa archipelago. There are a total of 4 vessels tending divers and 3 of these small boats are covering as many sites within the day as possible.  We need statically enough to quantify abundance but in this 19’ SAFE boat warmly called “ R/V Steel Toe” we are diving on the same site twice…Why? one could very well ask… and the reason is that there is a notion that bubbles escaping from normal SCUBA systems (or “open circuit ”)  could bias fish counts because the noise the bubbles make could either attract or spook fish from the area being surveyed.

Figure 2: The divers will spend up to an hour hovering over the reef and counting fish. Notice the lack of bubbles escaping from Ray Boland’s re-breather unit.

Figure 2: The divers will spend up to an hour hovering over the reef and counting fish. Notice the lack of bubbles escaping from Ray Boland’s re-breather unit.

The CREP fish team is taking this “does SCUBA bubbles effect fish counts?” question head on with a comparative study. And so, re-breathing comes into the fold. The R/V Steel Toe visits 3 sites a day where a team of scuba divers and a team of rebreather divers survey the same site on the same day….. randomly deciding which method goes first at each dive site.

Figure 3: Andrew Gray preps himself for a 75ft re-breather dive. His CREP colleagues using SCUBA are just finishing up their dive , they will be on the surface momentarily and quick chat about the direction of current and the line angle is all he needs before he rolls in. This comparative study is looking to see if the fish he sees has any stastical difference to what his colleagues just saw.

Figure 3: Andrew Gray preps himself for a 75ft re-breather dive. His CREP colleagues using SCUBA are just finishing up their dive , they will be on the surface momentarily and quick chat about the direction of current and the line angle is all he needs before he rolls in. This comparative study is looking to see if the fish he sees has any statistical difference to what his colleagues just saw.

The “Team Redundant” nickname refers to the, thorough planning, extra safety precautions, backup safety equipment and a 16 action item checklist that each re-breather diver completes prior to each dive. This check list runs thru the opening of valves, checking of sensors and calibrating dive computers and when everything checks out; each diver dons their 75 pound re-breather and breathes off the unit for 5 minutes before rolling of the boat slate-in-hand.

Figure 4: Andrew Gray and Tate Wester thoroughly examine and check their re-breather units prior to each dive. They are in the middle of their 16 action item checklist; demonstrating safe and best practices for closed circuit diving.

Figure 4: Andrew Gray (back) and Tate Wester (front) thoroughly examine and check their re-breather units prior to each dive. They are in the middle of their 16 action item checklist; demonstrating safe and best practices for closed circuit diving.

As the Coxswain , I read off the their 16 action item checklist , but I have no idea what each action is, means or requires the diver to conduct. However I hear “check” from each diver before we move to the next item. It’s obvious to me that years of rigorous training and a careful, methodical and observant personality give each diver the edge they need to safely dive with re-breathers. However for Andrew Gray, Ray Boland and Tate Wester , or as they affectionately call themselves “Team Redundant”  this silent diving is just another effective methodology to count and size Samoa’s reef fish.

Figure 5: “Team Redundant” hard at work

Figure 5: “Team Redundant” hard at work

Posted in coral reef ecosystem, Scientific Operations | Tagged , , , , , , , ,

SE16-02: Training Collaborators in American Samoa to Conduct Reef Fish Surveys

by Paula Ayotte

On April 4, 2016, I traveled to American Samoa to train partner scientists on methods used to conduct fish and benthic surveys, ultimately preparing them to join the Reef Fish Survey cruise (SE-16-02) aboard the NOAA Ship Oscar Elton Sette. The NOAA PIFSC Coral Reef Ecosystem Program (CREP) is leading this research cruise, but it is a multi-agency partnership—bringing together participants from the American Samoa Department of Marine and Wildlife Resources (DMWR), the Bigelow Laboratory for Ocean Sciences, and Woods Hole Oceanographic Institute.

Training blog (1)

Scientists taking a fish identification test.

Monitoring data collected by the CREP fish team are used to assess the status and trends of coral reef fish populations. This requires high standardized data collection methods. In order to collect high quality data for the CREP fish team, divers must undergo rigorous training in the Rapid Ecological Assessment (REA) fish stationary point count (SPC) survey method. The purpose of the training is for survey divers to develop the required skills in fish identification, fish size estimation, the survey method protocol and visually estimating benthic cover (coral, algae, crustose coralline algae, and sand), urchin counts, and habitat complexity.

I launched our comprehensive new online training package for the first time at the recent training course, hosted by the DMWR, with broader support from the American Samoa Coral Reef Advisory Group (CRAG) appointed by the Governor. The participation of DWMR partners also requires them to acquire reciprocity to dive with NOAA divers. NOAA CREP and DWMR fulfilled this requirement ahead of the training course so that our respective monitoring programs can work more collaboratively in future.

Participants in this week-long training included: Alice Lawrence, the Coral Reef Monitoring Fish Ecologist for the American Samoa Coral Reef Advisory Group (CRAG-DMWR); Motusaga Vaeoso, a coral reef monitoring technician and marine debris project coordinator (CRAG-DMWR); and Brittney Honisch, a research technician at the Bigelow Laboratory for Ocean Sciences in Maine. Several other scientists from DMWR as well as the American Samoa Environmental Protection Agency attended the first introductory day of classroom training.

After a full day of classroom training where scientists reviewed the methods, practiced counting and sizing fish, took a fish identification test, and ran a practice survey transect, they were ready to get in the water. Fortunately, the weather cooperated and the scientists spent the next three days diving off the DMWR boat in the waters around Tutuila. By the third day of diving the new survey divers felt comfortable and confident with the survey method and also practiced in-water emergency dive rescue skills.

On the final day, the divers returned to the classroom to practice entering their data into the database, review photos they had taken during the dives, and take one last fish identification test… which they all passed with flying colors! All three of these trainees will now join the CREP fish team on the Oscar Elton Sette to collect data for the NMFS reef fish survey cruise.

Training blog (11)

Scientists taking a fish identification test.

The CREP fish rapid ecological assessment training materials used during the training are now available online at: http://www.pifsc.noaa.gov/cred/survey_methods/fish_surveys/rapid_ecological_assessment_of_fish-survey_method_training.php.

Training blog (12)

Motu Vaeoso, Paula Ayotte, Brittney Honisch, and Alice Lawrence with coxswain Hanipale Hanipale (DMWR Enforcement).

 

Posted in coral reef ecosystem | Tagged , , , , , , , , , , , , ,

SE16-01: Samoa Researchers Join the NOAA Samoa Archipelago Fisheries Research Cruise

The final leg of SE16-01, the Samoa Archipelago Fisheries Research Cruise, took place around the islands of Upolu, Manono, and Savai’i, Samoa.  During this leg, researchers from 2 Samoa agencies, the Ministry of Natural Resources and the Environment (MNRE) and the Ministry of Agriculture and Fisheries (MAF) joined the cruise.  Both agencies brought their own research agendas to the cruise but also assisted the NOAA researchers in their mission.

Figure 1. NOAA and MNRE researchers conduct coral bleaching survey using snorkel.

Figure 1. NOAA and MNRE researchers conduct coral bleaching survey using snorkel.

MNRE assigned 2 researchers to conduct coral bleaching and seagrass surveys.  Coral bleaching surveys by MAF and NOAA researchers took place via snorkel at 23 sites around Savai’i and Upolu (Fig 1).  Preliminary findings indicate:

  • the reef slope is not as affected by bleaching as the reef flat:
    • reef slope = 10% bleached with 10% severity and primarily Pocillopora species
    • reef flat – 20% bleached with 25% severity and primarily Acropora (Fig. 2)
  • the 2015 bleaching event was more severe (60-70% bleached corals) then the current event.
  • in general, Samoa does not appear to be experiencing bleaching as severe as other places in the South Pacific (e.g. GBR) however, it is important to note that there is minor bleaching related to increased water temperature.
Figure 2. Bleaching of Acropora on the east side of Savai’i. Notice the bleaching of the branch tips.

Figure 2. Bleaching of Acropora on the east side of Savai’i. Notice the bleaching of the branch tips.

MNRE also conducted a seagrass snorkel survey around Manono tai Island.  The entire island was surveyed in one day (Maria Satoa is an extreme seagrass snorkel surveyor) (Fig. 3)!  Preliminary findings indicate:

  • confirmed 2 species of seagrass around the island (Halophila ovalis and Syringodium isoetifolium)
  • both species were found in shallower water but Syringodium isoetifolium was less abundant in deeper water
  • the SW side of the island had the greatest seagrass density (90% coverage) and the SE had the lowest density(2%)
  • both species on the western-most point of the island had cyanobacteria growing on the leaves (Fig.4)
Figure 3. MNRE staff surveying the seagrass beds and collect samples around Manono tai Island.

Figure 3. MNRE staff surveying the seagrass beds and collect samples around Manono tai Island.

Figure 4. NOAA and MNRE researchers consult about cyanobacteria growing on seagrass leaves.

Figure 4. NOAA and MNRE researchers consult about cyanobacteria growing on seagrass leaves.

MAF supplied a large amount of fishing ‘local knowledge’ and provided many staff members for NOAA operations.  They participated in bottomfishing operations from small boats, spearfishing, and the 2 MNRE surveys (Fig. 5).  At the end of each day they jumped in and assisted with the tedious and sometimes messy fish processing.  They also took the opportunity to search for many of the nearshore and offshore fish aggregating devices (FADs).  Unfortunately, only 1 of the nearshore FADs and none of the offshore FADs were still in place.

Figure 5. MAF staff participating in the various SE16-01 operations.

Figure 5. MAF staff participating in the various SE16-01 operations.

Over the last 10 days the ship’s complement was exposed to many aspects of Samoan culture.  We learned how to shred coconuts, the names of Samoan fish and fishing techniques and our vocabulary greatly expanded😉.  It’s been an honor and privilege to work with the Samoa researchers (Fig. 6) and we look forward to many more collaborative efforts.  For more on this collaborative effort, check out:

http://www.samoaobserver.ws/en/13_04_2016/local/4882/Local-scientists-benefit-from-international-project.htm

Fa’afetai.

Figure 6. MAF staff, keeping things safe!

Figure 6. MAF staff, keeping things safe!

For a cruise overview, click here.

To read about the SE16-01 Blog 1 – Outreach event with American Samoa Community College Students, click here.

To read about the SE16-01 Blog 2 – Secretary of the Office of Samoan Affairs, District Governor of Manu’a, and District Governor of American Samoa East District visit the NOAA Ship Oscar Elton Sette in Pago Pago, American Samoa, click here.

To read about the SE16-01 Blog 3 – Nightlight fishing for atule in American Samoa, click here.

To read about the SE16-01 Blog 4 – Bottomfishing for samples, click here.

To read about the SE16-01 Blog 5 – Spearfishing for samples, click here.

 

 

Posted in Fisheries Research and Monitoring, Scientific Operations | Tagged , , , , , , , , , , , , ,