What Happens When A Poisonous Fish Gets Poisoned?

by Melanie Abecassis and Thierry Work

Between June and October 2010, beach-goers all around the Hawaiian Islands were discovering dead pufferfish on the beach or distressed in the ocean, puffed up and floating. In some cases, puffers were found in pairs with one fish biting and holding another. Occasional reports of puffers acting aggressively towards each other were received, and in one instance, a puffer was observed actively attacking snorkelers in the water. Thus started a five-year long episode of CSI-Fish-Hawai‘i.

Pufferfish are poisonous fish and are mostly solitary animals that rarely interact with other fish. Researchers collected sick puffers, held them temporarily in fish tanks and noticed they struggled to remain submerged, ending up “bobbing” at the surface. This phenomenon affected three species of pufferfish, mainly stripebelly puffers (Arothron hispidus) with a minority of spotted puffers (A. meleagris) and porcupine fish (Diodon hysteria). Populations of spotted puffers that are routinely monitored by scientists on the west coast of Hawai‘i Island declined precipitously starting in 2009, and remained low from 2010 onwards, whereas no evident population change was seen for porcupine fish or stripebelly puffers.

Because pufferfish are highly toxic, they are not typically targeted for human consumption (except in Japan, where the meat of some pufferfish is considered a delicacy. Called fugu, it is extremely expensive and only prepared by trained, licensed chefs who know that one bad cut means almost certain death for a customer). However, fish die-offs are important to investigate in tropical marine ecosystems because they are honest signals of environmental perturbations that could damage populations of native species or, in some cases, impact public health.

Using various laboratory tools, veterinarians and chemists with the U.S. Geological Survey’s National Wildlife Health Center, Honolulu Field Station and NOAA’s National Ocean Service spent five years trying to identify the cause of death and discovered a series of marine toxins comprised of very small molecules that had never been identified before as the likely cause of this mass mortality. The toxins led to liver failure, acid base imbalance in the blood, and subsequent inability of fish to remain submerged. Their findings are striking in that 1) a marine toxin killed a species of fish that is, itself, toxic, 2) they identified a plausible mechanism (liver failure) to explain clinical signs of affected fish, and 3) this epidemic likely depleted some pufferfish populations. Scientists suspect the marine toxin was ingested, but the source remains a mystery.

PIFSC scientists collaborated on this project to investigate whether there were any abnormal ocean conditions that could have explained the timing of the fish die-off, but no clear link between ocean conditions and fish mortality was identified.

This study provides a template for marine fish kill investigations associated with marine toxins and highlights the need for more rapid and cost-effective methods to identify new marine toxins, particularly small molecules.

Read more: Pufferfish mortality associated with novel polar marine toxins in Hawaii

Seafloor Mapping Mission: Maui

By Kell Bliss

On 1 May 2015, four members of the EcoSpatial Information Team (ESI) in the Coral Reef Ecosystem Division, of NOAA’s Pacific Islands Fisheries Science Center, traveled to Maui to begin the first part of a two-part field mission. The mission involves mapping seafloor composition and coral cover, first on the west side of Maui between Ka‘anapali and Honolua Bay, and second, on the west side of Hawai‘i Island south of Kawaihae Harbor, depending on weather conditions. Both sites are priority areas designated by the State of Hawai‘i Division of Aquatic Resources and the NOAA Coral Reef Conservation Program and within the waters of the Hawaiian Islands Humpback Whale National Marine Sanctuary. The West Hawai‘i site is also a NOAA Habitat Blueprint focus area.

The Hawaiian Islands Humpback Whale National Marine Sanctuary’s M/V Koholā.

The Hawaiian Islands Humpback Whale National Marine Sanctuary’s M/V Koholā.

Dr. John Rooney, Rhonda Suka, and NOAA Corps LTJGs Kell Bliss and Kristin Golmon met up with ENS Carmen DeFazio to load gear onto the Hawaiian Islands Humpback Whale National Marine Sanctuary’s M/V Koholā. ENS DeFazio is the current operator in charge of the vessel for the Sanctuary and she familiarized the team with the vessel and in the first few days trained and qualified members of the ESI team to run the vessel.

The Koholā is an 11.6 meter AMBAR with twin 200 horsepower outboard engines capable of being operated from either the flying bridge or inside the sheltered cabin. A pot-hauler is attached to a davit to facilitate deploying the Towed Optical Assessment Device (“TOAD”) over the side.

Towed Optical Assessment Device (TOAD) sled and her cable. Photo credit: LTJG Golmon

Towed Optical Assessment Device (TOAD) sled and her cable. Photo credit: LTJG Golmon

The TOAD is an underwater camera sled designed to take photographs and video imagery of the seafloor. Ideally, the vessel drifts at a speed of about one knot to acquire high quality photos. The photos are used for mapping the distribution of key benthic organisms, such as hard corals, as well as providing ground-truthing data to integrate with acoustic multi-beam, bathymetric LiDAR (a remote sensing method), and other data for habitat mapping. Numerous partner agencies have provided additional ground-truthing data for this project, including the Division of Aquatic Resources, the U.S. Geological Survey, The Nature Conservancy, the U.S. Army Corps of Engineers, the Hawai‘i Institute for Marine Biology, the NOAA Biogeography Program, and other teams within the Coral Reef Ecosystem Division.

On arrival day, after offloading some gear from the boat, ENS DeFazio, Dr. Rooney, and LTJG Bliss moved the Koholā from her home port in Ma‘alaea to a pier in Lahaina for the duration of the first part of the mission. Lahaina Harbor is closest to the working grounds on the west side of the Maui. Day two was spent testing the TOAD, setting up the scientific gear, and conducting one tow survey.

LTJG Bliss and LTJG Golmon hand-hauling the TOAD and her cable back aboard when the pot hauler died. Photo credit: LTJG Golmon

LTJG Bliss and LTJG Golmon hand-hauling the TOAD and her cable back aboard when the pot hauler died. Photo credit: LTJG Golmon

The remainder of the Maui portion of the project involved selecting locations to launch the TOAD each day depending on water depth and weather conditions. As with any field project, there were numerous operational challenges to overcome. The team dealt with a pot-hauler that stopped working and had to pull the TOAD up by hand, not an easy task, but successfully retrieved the sled and then installed the spare pot-hauler for the next day’s surveys.

Can you spot the flying gurnard in this seafloor image taken by the TOAD?

Can you spot the flying gurnard in this seafloor image taken by the TOAD?

The data collected on the survey, as well as data previously collected by the ESI team and partners, will be used to create seafloor maps that will depict areas covered by sediment and rock as well as the major structural features such as pavement, aggregate reef, patch reef, and reef rubble. Major types of biological cover will be identified as well, such as coral, macroalgae, and coralline algae. The maps will be available online and will provide important information for watershed and marine resource managers to enable them to plan effective actions to improve the health and resilience of Maui’s coral reef ecosystems. Plans are being developed to improve the health of coral reef ecosystems off West Maui by reducing the flow of terrestrial sediments into the coastal ocean. Locating existing or potential coral reef areas will help managers plan effective mitigation efforts, or any other management activity that includes a spatial component, for example, delineating marine protected areas and anchorages.

Researchers survey a high-priority coral reef area off Maui

By John Rooney
R/V AHI. NOAA photo

R/V AHI. NOAA photo

A team of scientists from the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center on Tuesday began a mission to conduct acoustic and optical surveys of the waters of coral reef ecosystems in Maui. The team shipped their 8-m survey launch R/V AHI, equipped with a diesel generator to provide power and a Reson 8101ER multibeam echosounder, to Maui from O’ahu last week to support this survey effort.

Optical surveying will focus on one of two high-priority coral reef sites in Hawai’i identified by the Hawai’i Department of Land and Natural Resources (DLNR) and NOAA’s Coral Reef Conservation Program (CRCP): an area near Kahekili off West Maui (see map below at left). In 2013, the U.S. Geological Survey (USGS) conducted shallow-water mapping in the area, generally at depths of 10–40 m. The present survey effort on Feb. 4–21 will collect video and still photographs of the seafloor at depths of 30–100 m to overlap with and extend the USGS maps out to the 3-mile boundary of state waters or to a depth of ~100 m.

The red box in this map indicates the survey area where the camera sled will be deployed. This area off Kahekili, Maui, has been designated by the Hawai’i Department of Land and Natural Resources and NOAA’s Coral Reef Conservation Program as one of two high-priority sites in the state.

The red box in this map indicates the survey area where the camera sled will be deployed. This area off Kahekili, Maui, has been designated by the Hawai’i Department of Land and Natural Resources and NOAA’s Coral Reef Conservation Program as one of two high-priority sites in the state (click image for a larger version).

For the surveys, members of the CRED ecospatial information team will use an underwater camera sled, called the “TOAD,” for towed optical assessment device (see photo below at right). The data collected during these TOAD surveys will enable the team to map the dominant seafloor structures (e.g., pavement, patch reef, and sand) and the major classes of biologic cover (e.g., coral and macroalgae) in the area. The extended maps will provide DLNR and other management agencies and coastal and marine stakeholders with the spatial data needed to make informed decisions about the management of nearshore marine resources and habitats.

The second goal of this survey mission is to fill gaps in existing maps that depict seafloor depths, or bathymetry, with a high degree of detail. No type of seafloor map is of higher value to more people than are maps of high-resolution bathymetry. However, gaps in existing maps (see map below) inhibit their use for many purposes.

To collect data to fill some of those gaps, the survey team will operate the multibeam echosounder on the R/V AHI. They’ll first fill remaining gaps in the data for the Kahekili high-priority site, and then they will spend the remaining time surveying in the most windward and exposed sites in which they are able to operate.

The video and still photographs collected by the towed optical assessment device (TOAD), the camera sled shown being deployed from a ship in this photo, can be analyzed to help map the character of benthic habitats. NOAA photo

The video and still photographs collected by the towed optical assessment device (TOAD), the camera sled shown being deployed from a ship in this photo, can be analyzed to help map the character of benthic habitats. NOAA photo

After the mission, the team will clean and process the data and then provide them to NOAA’s National Geophysical Data Center to be made publicly available for download. The data also will be provided to the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawai’i at Mānoa for inclusion in the synthesis of high-resolution bathymetry data that SOEST has maintained for many years.

Funding for this project was provided by the CRCP. We thank the Hawai’i DLNR for graciously providing logistical support and the USGS for going out of their way to send us copies of their existing data and publications.

Follow this link for a PDF version of this story about the latest mapping surveys off Maui.

For more information about this mission and CRED benthic habitat mapping, contact John Rooney, program manager for the ecospatial information team, at john.rooney@noaa.gov.
This map shows existing high-resolution bathymetry collected around Maui, color coded by depth and superimposed over a nautical chart.

This map shows existing high-resolution bathymetry collected around Maui, color coded by depth and superimposed over a nautical chart.

Researchers complete surveys of coral disease off the north shore of Kaua`i

By Bernardo Vargas-Ángel

Members of the benthic team of the PIFSC Coral Reef Ecosystem Division (CRED) returned to Honolulu on May 8 from a week-long deployment on Kaua`i, where they conducted surveys as part of a project funded by PISFC and NOAA’s Coral Reef Conservation Program (CRCP) to better understand the prevalence and spatial distribution of an outbreak of bacterial coral disease that was reported in 2012 for areas off the north shore of Kaua`i.

Benthic team member and NOAA diver Hatsue Bailey conducts coral disease surveys using the belt-transect method on May 4 in Hanalei Bay, Kaua`i. NOAA photo Bernardo Vargas-Ángel

Benthic team member and NOAA diver Hatsue Bailey conducts coral disease surveys using the belt-transect method on May 4 in Hanalei Bay, Kaua`i. NOAA photo by Bernardo Vargas-Ángel

A 4-member team of CRED scientists—Hatsue Bailey, Matt Dunlap, Brett Schumacher, and Bernardo Vargas-Ángel—conducted surveys on April 30–May 7 at 36 sites in Hanalei Bay, Wainiha Bay, and `Anini Reef to acquire detailed data on demographics and health conditions of coral communities in these areas. This survey effort expanded and complemented the investigations already undertaken by Thierry Work, PhD, of the U.S. Geological Survey (USGS), and Greta Aeby, PhD, of the Hawai`i Institute of Marine Biology (HIMB), University of Hawai`i at Mānoa. The team completed belt-transect surveys at predetermined reef locales and sites, which were selected in consultation with scientists from partner agencies, the USGS and HIMB, as well as with other local experts. The data from these surveys will be used to provide the basis for quantitative estimates of disease prevalence. These surveys and their data are congruent with current, historical, and future coral reef monitoring activities conducted and data collected by CRED in the main Hawaiian Islands and Pacific-wide under the auspices of the CRCP’s National Coral Reef Monitoring Program.

Semicircular areas of rapid tissue loss, infected with filamentous bacteria on a colony of the rice coral Montipora patula, as seen in this photo taken on May 6 on `Anini Reef, Kaua`i. These areas are characteristic of the disease outbreak event currently developing on coral reefs along the north shore of Kaua`i. NOAA photo Bernardo Vargas-Ángel

Semicircular areas of rapid tissue loss, infected with filamentous bacteria on a colony of the rice coral Montipora patula, as seen in this photo taken on May 6 on `Anini Reef, Kaua`i. These areas are characteristic of the disease outbreak event currently developing on coral reefs along the north shore of Kaua`i. NOAA photo by Bernardo Vargas-Ángel

Preliminary findings from these surveys corroborate the occurrence of disease “hotspots” within each of the reef systems surveyed and confirm the unique nature of this event. We’d like to extend special thanks to Thierry Work, Greta Aeby, and Eyes of the Reef volunteer Terry Lilley for sharing their knowledge regarding this outbreak and making our mission a complete success. We look forward to fostering these and other collaborations as we continue to work together for the betterment of reefs in Hawai`i and the larger Pacific Islands region.