Hawaiian Waters Research Articles

Detection and modeling of Staphylococcus aureus and fecal bacteria in Hawaiian coastal waters and sands.

Microbial pollution of recreational waters leads to millions of skin, respiratory, and gastrointestinal illnesses globally. Fecal indicator bacteria (FIB) are monitored to assess recreational waters but may not reflect the presence of Staphylococcus aureus, a global leader in bacterial fatalities. Since many community-acquired S. aureus skin infections are associated with high recreational water usage, this study measured and modeled S. aureus, methicillin-resistant S. aureus (MRSA), and FIB (Enterococcus spp., Clostridium perfringens) concentrations in seawater and sand at six beaches in Hilo, Hawai'i, USA, over 37 sample dates from July 2016 to February 2019 using culturing techniques. Generalized linear models predicted bacterial concentrations with physicochemical and environmental data. Beach visitors were also surveyed on their preferred activities. S. aureus and FIB concentrations were roughly 6-78 times higher at beaches with freshwater discharge than at those without. Seawater concentrations of Enterococcus spp. were positively associated with MRSA but not S. aureus. Elevated S. aureus was associated with lower tidal heights, higher freshwater discharge, onsite sewage disposal system density, and turbidity. Regular monitoring of beaches with freshwater input, utilizing real-time water quality measurements with robust modeling techniques, and raising awareness among recreational water users may mitigate exposure to S. aureus, MRSA, and FIB. PRACTITIONER POINTS: Staphylococcus aureus and fecal bacteria concentrations were higher in seawater and sand at beaches with freshwater discharge. In seawater, Enterococcus spp. positively correlated with MRSA, but not S. aureus. Freshwater discharge, OSDS density, water turbidity, and tides significantly predicted bacterial concentrations in seawater and sand. Predictive bacterial models based upon physicochemical and environmental data developed in this study are readily available for user-friendly application.

Beaked whales and El Niño: evidence for ENSO effects on Blainville’s beaked and goose-beaked whale space use in Hawaiian waters

Beaked whales and El Niño: evidence for ENSO effects on Blainville’s beaked and goose-beaked whale space use in Hawaiian waters

False killer whales and fisheries in Hawaiian waters: evidence from mouthline and dorsal fin injuries reveal ongoing and repeated interactions

False killer whales and fisheries in Hawaiian waters: evidence from mouthline and dorsal fin injuries reveal ongoing and repeated interactions

Mercury accumulation and biomarkers of exposure in two popular recreational fishes in Hawaiian waters

Mercury (Hg) exposure has not been examined in many recreational nearshore fish species that are commonly consumed around the Hawaiian Islands. Specific gene transcripts, such as metallothionein (MET) and thioredoxin reductase (TrxR), can be used to examine Hg exposure responses in aquatic organisms. This study measured total mercury (THg) in four species from two groups of Hawaiian nearshore fishes: giant trevally (Caranx ignobilis, n = 13), bluefin trevally (C. melampygus, n = 4), sharp jaw bonefish (Albula virgata, n = 2), and round jaw bonefish (A. glossodonta, n = 19). Total Hg accumulation and abundance profiles of MET and TrxR were evaluated for muscle, liver, and kidney tissues. Total Hg in round jaw bonefish and giant trevally tissues accumulated with length and calculated age. In round jaw bonefish tissues, mean THg was greater in kidney (1156 ng/g wet mass (wm)) than liver (339 ng/g wm) and muscle (330 ng/g wm). Giant trevally muscle (187 ng/g wm) and liver (277 ng/g wm) mean THg did not differ significantly. Fish species in this study were compared to commercial and local fish species with state and federal muscle tissue consumption advisories based on THg benchmarks developed by the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA). Both bonefishes had mean muscle THg that exceeded benchmarks suggesting consumption advisories should be considered. MET transcript in round jaw bonefish kidney tissue and kidney THg exhibited a marginally significant positive correlation, while TrxR transcript in liver tissue negatively correlated with increasing liver THg. These results contribute to our understanding of Hg exposure associated health effects in fish.

New records and species of deep-sea squat lobsters (Galatheoidea, Munidopsidae) from the Hawaiian Archipelago: an integrative approach using micro-CT and barcodes.

The Hawaiian Archipelago remains extensively under-sampled for many marine invertebrate taxa, including squat lobsters. During the last few years, several deep-sea expeditions carried out in the Pacific Ocean have conducted opportunistic collections of specimens and image data from the vicinity of Hawai'i. Here we describe a new species: Munidopsis hawaii sp. nov. and provide new records for Munidopsidae in the Archipelago and its associations. We illustrate and describe the new species using an integrative approach including micro-CT 3D imaging. Phylogenetic analyses of the species collected from seamounts from Hawai'i indicate that the new species represents a divergent lineage compared to morphologically similar species such as M. dispar and M. papanui. We also study the genetic distances for the species recorded in Hawai'i and other populations of the same species in the adjacent West Pacific. Three species are now known in the Hawaiian region. We also compiled identifications from images captured with ROVs in the area. These observations suggest that munidopsid species are common in the deep sea of Hawaiian waters below 1,000 m.

Trends in collisions between vessels and North Pacific humpback whales (Megaptera novaeangliae) in Hawaiian waters (1975–2011)

Injury from collisions with vessels is a growing threat worldwide for many species of whales. Thirty seven years of historical records were examined for evidence of vessel collisions with humpback whales in the main Hawaiian Islands. Between 1975 and 2011, 68 collisions between vessels and whales were reported including 59 witnessed collisions and 9 observed whale injuries that were consistent with a recent vessel collision. No collisions were immediately lethal. The waters between Maui, Molokai, Lanai and Kahoolawe, which are known to have one of the highest concentrations of humpback whales in the Hawaiian Islands, had the highest incidence of collisions. Over 63% of the collisions involved calves and subadults, suggesting a greater susceptability towards collisions among younger animals. The rate of collisions increased significantly over the final twelve breeding seasons of the study and was greater than predicted by the estimated annual increase in the whale population, suggesting that the rising number of reported collisions cannot be explained solely by the annual increase in whale abundance. Although the total number of registered vessels and shipping traffic in Hawaii remained relatively constant between 2000 and 2010, there was a significant increase in the number of vessels between 7.9m and 19.8m in length. Vessels within this size range were also the most commonly involved in collisions during the study period, accounting for approximately two thirds of recorded incidents. It is concluded that from 1975–2011, there was a significant increase in reports of non-lethal collisions between vessels and humpback whales, especially calves and subadults, in the main Hawaiian Islands that likely reflects a combination of factors including the recovery of the population of North Pacific humpback whales, increases in traffic of particular vessel types, and increased reporting practices by operators of vessels.

A first look at whale sharks in Hawaiian waters: Using citizen science to study the world's largest fish, Rhincodon typus

Abstract The world's largest fish, the whale shark (Rhincodon typus), is a circum‐tropically distributed and globally endangered species, that is widely studied at predictable aggregation sites. The main Hawaiian Islands are not known to have large aggregations of whale sharks; however, they have been anecdotally reported here with some regularity. To date, little is known about this charismatic species in Hawaiian waters. This study is the first effort to examine whale shark demographics and movements in a previously unstudied region of the world. Here, citizen science was used to investigate the abundance, seasonality (if any) and occurrence of whale sharks in the waters around the main Hawaiian Islands. A total of 309 individual whale sharks were identified from sightings between 1991–2020 by their unique spot patterns, most of which (74%) were reported between 2018 and 2020. Estimated whale shark total length ranged from 2–12 m (mean 6.1 m), with both juvenile and mature males and females represented in the dataset. The best‐fit Lagged Identification Rate (LIR) model for these data suggests that individuals sighted in Hawaiian waters are transient in nature, supporting the empirical data (88% of sharks sighted only once). Although using citizen science data can have inherent biases, these results present a conservative first assessment of the demographics of whale sharks in Hawaiian waters. For an Endangered species assessed as Largely Depleted by the IUCN Green Status of Species, highlighting Hawai’i as an important habitat for the whale shark – mainly as a migratory corridor or navigational waypoint – is a crucial step in understanding their ecology in the Pacific in order to develop effective management plans.

Examining distribution patterns of foraging and non-foraging sperm whales in Hawaiian waters using visual and passive acoustic data

Following the end of over a century of intensive commercial whaling in 1986, the monitoring and assessment of sperm whale populations is essential for guiding management and conservation decisions for their recovery. Species distribution models (SDMs) are a useful tool for examining and predicting cetacean distribution patterns and typically incorporate visual, ship-based observations. However, understanding sperm whale distribution and habitat use based solely on surface visual observations is challenging due to the significant amount of time sperm whales spend foraging at depth. For the endangered sperm whale population occurring in Hawaiian waters, we used visual and passive acoustic data collected during four annual NOAA marine mammal line-transect surveys and a suite of biologically relevant environmental variables to develop SDMs within a generalized additive modeling framework to study the distribution of sperm whale groups throughout the island chain. Additionally, the passive acoustic data allowed us to differentiate sperm whale groups as foraging or non-foraging based on their click types to account for differences in distribution and behavior within the archipelago. Foraging groups were predicted primarily in the northwestern region of the archipelago between Laysan Island and Pearl and Hermes Reef as well as north of Maui and Hawaiʻi in the main Hawaiian Islands. Non-foraging groups were predicted to be more uniformly distributed throughout the archipelago. Foraging whale models selected temperature at 584 m depth, surface chlorophyll, and location, while the only significant variables for non-foraging whale models included the standard deviation of sea surface height and location. Each variable provides insight into the oceanographic processes influencing prey abundance and, thus, sperm whale foraging behavior. This study furthers our understanding of the distribution patterns for the sperm whale population in Hawaiʻi and contributes methods for building SDMs with visual and passive acoustic data that may be applied to other cetacean species.

The genome of a giant (trevally): Caranx ignobilis.

Caranx ignobilis, commonly known as giant kingfish or giant trevally, is a large, reef-associated apex predator. It is a prized sportfish, targeted throughout its tropical and subtropical range in the Indian and Pacific Oceans. It also gained significant interest in aquaculture due to its unusual freshwater tolerance. Here, we present a draft assembly of the estimated 625.92 Mbp nuclear genome of a C. ignobilis individual from Hawaiian waters, which host a genetically distinct population. Our 97.4% BUSCO-complete assembly has a contig NG50 of 7.3 Mbp and a scaffold NG50 of 46.3 Mbp. Twenty-five of the 203 scaffolds contain 90% of the genome. We also present noisy, long-read DNA, Hi-C, and RNA-seq datasets, the latter containing eight distinct tissues and can help with annotations and studies of freshwater tolerance. Our genome assembly and its supporting data are valuable tools for ecological and comparative genomics studies of kingfishes and other carangoid fishes.

North Pacific minke whales call rapidly when calling conspecifics are nearby

North Pacific minke whale (Balaenoptera acutorostrata) boing calls are commonly detected in Hawaiian waters. When producing boing vocalizations, minke whales seem to be in one of two calling behavioral states. Most often minke whales produce boings with inter-call intervals of several minutes, but sometimes minke whales call rapidly with inter-call intervals of less than a minute. Since minke whales are difficult to detect visually, cue-rate-based density estimation using passive acoustic monitoring has been proposed. However, the variables that influence cue rate or calling rate are poorly understood in most whales, including minke whales. We collected passive acoustic recordings from 47 bottom-mounted hydrophones at the Pacific Missile Range Facility’s instrumented range off the coast of Kauaʻi, Hawaiʻi to test the hypothesis that minke whales call more rapidly when closer in proximity to other calling conspecifics. A total of 599 days of data were recorded between August 2012 and July 2017 and were automatically post-processed to detect, classify, and localize calls. Localized calls were grouped into tracks and manually validated, resulting in 509 individual tracks composed of 36,033 calls within a 16 x 39 km focal study area. Tracked minke whales exhibited a strong bimodal call rate with means of one call every 6.85 min (σ= 2.54 min) and 0.63 min (σ= 0.36 min). We ran hidden Markov models to quantify the relationship between call rate and the distance to the nearest calling conspecific. Overall, the probability of the higher call rate occurring increased as the distance to the nearest conspecific decreased, and the probability of the lower call rate occurring increased as the distance to the nearest conspecific increased. We also examined individual track data and found that minke whales may also exhibit other responses (i.e. increased speed, changes in heading, and cessation of calling) when calling conspecifics are nearby. These findings provide new information about minke whale calling behavior in what is likely a breeding area.

Striped marlin in their Pacific Ocean milieu: Vertical movements and habitats vary with time and place

Striped marlin, Kajikia audax, a top bycatch of the longline fishery, has been designated as being in overfished condition in the Western and Central North Pacific, and overfishing is still occurring. This prompts an urgent need to devise conservation and management measures based on the best, current information on the biology and ecology of this species. Despite decades of conventional tagging around the Hawaiian waters, ecological research on striped marlin in the Central North Pacific has been lacking since 2005, and little is known about striped marlin’s vertical habitat, diving behavior and bycatch vulnerability in this area. To address this knowledge void, 31 popup satellite archival tags (4 X-Tags; Microwave Telemetry, Inc. and 27 MiniPATs; Wildlife Computers Inc.) were deployed on striped marlin (138-192 cm eye fork length) between 2016 and 2019 via the Hawaii-based longline fleet. Transmitted time series records revealed striped marlin spent 38 and 81% of their day and night in the top 5 m, with median daytime and night depths of 44 m and 2 m, respectively. Temperatures experienced were 23.3°C, daytime median, and 24.6°C, nighttime median, to a minimum of 7.6°C at the deepest depth logged, 472 m. Striped marlin exhibited distinct swimming behaviors, including diel depth distributions, excursions around the top of the thermocline, and extended time at the surface, most likely reflecting the dynamic biophysical environment and intrinsic life history of this highly migratory predator. High post-release survivorship (86%) in tagged striped marlin, and their predominant use of the sea surface and mixed layer indicate that live release measures can be a viable bycatch reduction strategy.

Species Identification of Larval Fish in Hawaiian Waters Using DNA Barcoding

Taxonomic information is important to fisheries management and conservation. In this study, we collected 95 specimens of larval fish from Hawaiian waters and a total of 92 mitochondrial COI barcode sequences were obtained, representing 20 species, 18 genera and 12 families. The determined average Kimura-2-parameter distances within species, genera, families, and orders were 0.72%, 25.99%, 26.30%, and 27.50%, respectively, and the mean interspecific distance was found to be 36-fold higher than the mean intraspecific distance. Phylogenetic tree analysis showed that individuals belonging to the same species were clustered together and could be clearly distinguished. The findings of this study can make a valuable contribution to our knowledge of the diversity and dispersal of larval fish in Hawaiian waters.

Alatina alata box jellyfish monthly migrations in Hawai’i: Lunar and physical oceanographic triggers

Alatina alata, a species of box jellyfish, is found in distinct localities throughout tropical zones in the Atlantic, Pacific, and Indian Oceans, and is responsible for the most severe stings reported in Hawaiian coastal waters. Alatina alata is unique among species of box jellyfish (Cubozoa) in that it is only observed in shallow shoreline waters during lunar period-specific monthly mass aggregations and beaching events, which occur 8–10 days after each full moon. At other times of the lunar cycle, this species has been documented in pelagic zone surveys and is not observed close to shore (0 to 5 meter deep area, 0–100 m from shoreline). To assess potential ecological and environmental triggers for the synchronized shoreward migration behavior of Alatina alata, we investigated 14 years of beach count data in relation to lunar transit, luminosity, tides, and ocean currents using: a 14-year time series of Alatina alata pre-dawn counts; morphometric and reproductive status analyses; three full-transect nighttime shipboard observations; modeling studies; and additional supporting data. Model simulations show a persistent anticyclonic eddy in the study area, which may act as a source point for the jellyfish. Additionally, in situ night-long observations over three separate months revealed for the first time that Alatina alata actively swam en masse from over one mile offshore towards the shore before moonrise. Over 500 animals were observed and all showed strong shoreward swimming behavior perpendicular to the prevailing current. While the monthly populations each demonstrated heterogeneity with regard to size and beaching time, there was a slight trend towards the beaching of larger jellyfish first. Despite this heterogeneity in size, all animals were sexually mature adults replete with gametes or freshly spent. For the first time, we document that a key number of hours of darkness between twilight and moon rise correlate with the migration, and we hypothesize that this lunar cycle specific event triggers gonadal maturation in adult jellies, and maturation then triggers migrations to the shallow reef zone for spermcast mating.

Propagation and attenuation of swell energy in the Pacific Ocean

Understanding the characteristics of swell propagation is practical for swell monitoring, early warning and wave power generation. In this study, the attenuation rate of swell energy during the propagation process is defined. Then, the propagation, attenuation and intraseasonal oscillation characteristics of swell energy in the Pacific Ocean are analyzed based on the 40-year European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA-40). Results show that (1) The swells generated from the North Pacific Ocean westerlies (NPOW) and the South Pacific Ocean westerlies (SPOW) usually propagate to the low latitude waters of the Pacific Ocean. (2) Swells in Hawaiian waters, Cologne Islands waters and Iquique waters mainly originate from the winter hemisphere. (3) It takes approximately 8 days for the swell to propagate from the SPOW to Cologne Islands waters. It takes approximately 7.5 days for the swell to travel from the NPOW to Cologne Islands waters. (4) An obvious attenuation of swell energy of 60%–90% occurs during the propagation process. (5) Swell energies in the SPOW, NPOW, Hawaiian waters, Cologne Islands waters and Iquique waters share a common quasi-biweekly oscillation. The attenuation rate of the swell energy has a significant quasi-weekly or quasi-biweekly oscillation.

Humpback Vocalizations

Humpback Vocalizations Rajiv Mohabir (bio) Rajiv Mohabir, poem, humpback, whales, Hal Whitehead, Luke Rendell, whale song In any birthing area, humpbacks sing the same, slowly evolving song. Learning strains from one another, they sing across the fathoms, their phrases and themes shifting in a pattern of small changes until they stitch new songs of older material. Songs at the end of the summer transform from the beginning of the season. Biologists Hal Whitehead and Luke Rendell write that, in Hawaiian waters, groups of the North Pacific variety alter their own songs in response to songs they have heard from other, very distant, humpbacks. This suggests music carries across thousands of miles. When apart the songs of different socializing groups evolve at similar rates. Or at some meeting place mid-migration do humpbacks gather? ________ Mysticetes do not have phonic lips or a museau de singe as with whales like odontocetes Larynges large as British call boxes emit frequencies Megaptera novaeangliae's U- folds between upper and lower respiratory systems vibrate [End Page 93] ________ To hear sound and song and noise alike, scientists must dig further into the biology of a humpback's curved bulla. They know it attaches to the cetacean's jaw. The bulla looks like a conch shell or a giant clam that's been warped into a cave. Or it looks like a sliced mushroom or the mouth of a cowrie shell, but delicate. For sound to be realized in the tympanic plate, fat and soft tissue must vibrate against the jaw. The cochlea joins to the periotic by a thin membranelike bone. This formation, the tympanoperiotic complex, processes soundthrough bone conduction. ________ No one knows the why or where of it, but most agree whale song is moving. Why else send recordings in the Voyager spacecraft on the Golden Record? Is it the slow erasure of a species that wails out? Humans look for meaning and aesthetics in what they cannot understand— Biologists Whitehead and Rendell wonder why whale song rhymes or is perceived as rhyming through pattern repetition. Is it lyrical? Is it cetacean rhetoric? How human language breaks apart at the point of conception. The echo is amniotic. We, once aquatic, heard as whales do. ________ Megaptera novaeangliae's tympanoperiotic complex is designed to hear songs across great distances at frequencies below what the human ear can discern. It is a delicate instrument of song and divination, an environment under threat of shipping lanes [End Page 94] and naval sonar pulses. Songs are made of notes, or base units that humpbacks emit at 30–4,000 hertz, which is in the range of human hearing. Acoustic trauma will rupture the process— whales no longer able to tell how deep they dive. The pressure crushes— ________ In representations of the structure of humpback vocalizations, bioacousticians chart the anatomy of the line. Repetition, irregularity, looseness, and deft shifts of breath and phrase magic the water column. aaa bcb cbc ded eff ded eff g The rhyme sense in a complete song leaves the listener in a sonically unfamiliar place. In fact, the g cascades, a grand departure—a kind of poetic anticlosure asking for riff and response. Perhaps this is an eight-stanza poem, mediated through human interpretation of what we can only imagine, not living in a three-dimensional water column. ________ O O O O O O O O O O O O O O O O ________ OAccording to cetacean biologists, a unit may be imagined tO be nOtes of humpback song.| | | O | O | O | A collection of units is called a phrase (Of up tO ten seconds). Modulated O frequency O| | O | | | | and amplitude, the nOtes are wrOught into phrases humpbacks repeat into a theme. Whales,| O O O | | | | | which scientists postulate sing for aesthetics' sake (hence poetry), add theme to theme, they| | | | | | weave songs that last for up to twenty to thirty minutes each. Some, they repeat for days. [End Page 95] ________ Whale song constantly evolves though the extinction event looms—That great god. Whales in the same regions sing similar, if not the same, songs during the same times, each whale shifting tune and phrasing to...

Tracking time differences of arrivals of multiple sound sources in the presence of clutter and missed detections.

Acoustic line transect surveys are often used in combination with visual methods to estimate the abundance of marine mammal populations. These surveys typically use towed linear hydrophone arrays and estimate the time differences of arrival (TDOAs) of the signal of interest between the pairs of hydrophones. The signal source TDOAs or bearings are then tracked through time to estimate the animal position, often manually. The process of estimating TDOAs from data and tracking them through time can be especially challenging in the presence of multiple acoustically active sources, missed detections, and clutter (false TDOAs). This study proposes a multi-target tracking method to automate TDOA tracking. The problem formulation is based on the Gaussian mixture probability hypothesis density filter and includes multiple sources, source appearance and disappearance, missed detections, and false alarms. It is shown that by using an extended measurement model and combining measurements from broadband echolocation clicks and narrowband whistles, more information can be extracted from the acoustic encounters. The method is demonstrated on false killer whale (Pseudorca crassidens) recordings from Hawaiian waters.

Physical mechanisms driving biological accumulation in surface lines on coastal Hawaiian waters

Lines of smooth ocean surface water known as “slicks” appear in coastal waters worldwide and can be caused by a number of natural mechanisms. Off the western coast of the island of Hawai‘i, USA, internal waves, submarine groundwater discharge, tidal fronts, and headland fronts were all observed to cause the formation of slicks. Neuston net sampling showed slicks to contain enhanced densities of phytoplankton, zooplankton, larval invertebrates, larval fish, and plastic fragments when compared to ambient water. In particular, internal wave slicks were observed to be both the most frequently occurring type of slick and the overall strongest accumulator of neustonic organisms and plastics when compared to the other types of slicks. Satellite imagery illustrated that slicks are visible along most of the West Hawai‘i coastline more than 75% of the time. Furthermore, acoustic backscatter observations showed that the accumulation associated with slicks frequently extended from the surface to depths of 5 m. These findings highlight the important roles internal wave slicks can have in coastal ecosystems.

Singing Fin Whale Swimming Behavior in the Central North Pacific

Male fin whales sing using 20 Hz pulses produced in regular patterns of inter-note intervals, but little is known about fin whale swimming behavior while they are singing. Even less is known about fin whales in Hawaiian waters because they have rarely been sighted during surveys and passive acoustic monitoring has been limited to sparse hydrophone systems that do not have localization capabilities. We hypothesized that fin whale kinematics may be related to their singing behavior, or external variables such as time and sea state. To investigate this hypothesis, we analyzed 115 tracks containing 50,034 unique notes generated from passive acoustic recordings on an array of 14 hydrophones from 2011 to 2017 at the U.S. Navy Pacific Missile Range Facility off Kauai, Hawaii. Fin whales swam at an average speed of 1.1 m/s over relatively direct paths. We incorporated the whales' speed and turning angle into hidden Markov models to identify different behavioral states based on the whales' movements. We found that fin whale kinematic behavioral state was related to the vocalization rate (also known as cue rate) and time of day. When cue rate was higher, fin whales were more likely to swim slower and turn more than when cue rate was lower. During the night, fin whales were also more likely to swim slower and turn more than during the day. In addition, we examined whether the presence of singing fin whales was related to time and sea state using generalized additive models. Fin whale track presence was affected by day of the year and song season, and possibly also wind speed and wave height. Although the track kinematics from the fin whale tracks presented here are limited to a subset of whales that are acoustically active, they provide some of the only detailed movements of fin whales in the region and can be compared against fin whale swim speeds in other regions. Understanding how fin whale swimming behavior varies based on their vocalization patterns, time, and environmental factors will help us to contextualize potential changes in whale behavior during Navy training and testing on the range.

Site fidelity, spatial use, and behavior of dwarf sperm whales in Hawaiian waters: using small‐boat surveys, photo‐identification, and unmanned aerial systems to study a difficult‐to‐study species

AbstractDwarf sperm whales (Kogia sima) have been studied rarely at sea. We used photo‐identification, boat‐ and drone‐based behavioral observations, and citizen science photo contributions to examine site fidelity, spatial use, and behavior in Hawaiʻi. Sighting rates were highest in island slope (500–1,000 m) waters. Over 40% of photo‐identified individuals were linked by association in the same social network. More than half of the very distinctive individuals were seen more than once, and 28.5% were seen in multiple years, with one individual seen 14 times over a 15‐year span. Resighted individuals and those in the main cluster of the social network were found in significantly shallower water than individuals that were not resighted or that were in isolated clusters. Distances between resighting locations suggest small home ranges. This suggests an insular slope‐dwelling population that overlaps with an offshore population. Evidence of unsuccessful predatory attempts by large sharks was recorded on four individuals, and linear wounds consistent with interactions with line fisheries were documented on three individuals. Surface and subsurface behavior recorded by drone revealed vigilance behavior likely to minimize predation risk. Lessons learned from this study can be applied elsewhere to increase knowledge of this poorly known and difficult‐to‐study species.

Compact Color Biofinder (CoCoBi): Fast, Standoff, Sensitive Detection of Biomolecules and Polyaromatic Hydrocarbons for the Detection of Life.

We have developed a compact instrument called the "COmpact COlor BIofinder", or CoCoBi, for the standoff detection of biological materials and organics with polyaromatic hydrocarbons (PAHs) using a nondestructive approach in a wide area. The CoCoBi system uses a compact solid state, conductively cooled neodymium-doped yttrium aluminum garnet (Nd:YAG) nanosecond pulsed laser capable of simultaneously providing two excitation wavelengths, 355 and 532 nm, and a compact, sensitive-gated color complementary metal-oxide-semiconductor camera detector. The system is compact, portable, and determines the location of biological materials and organics with PAHs in an area 1590 cm2 wide, from a target distance of 3 m through live video using fast fluorescence signals. The CoCoBi system is highly sensitive and capable of detecting a PAH concentration below 1 part per billion from a distance of 1 m. The color images provide the simultaneous detection of various objects in the target area using shades of color and morphological features. We demonstrate that this unique feature successfully detected the biological remains present in a 150-million-year-old fossil buried in a fluorescent clay matrix. The CoCoBi was also successfully field-tested in Hawaiian ocean water during daylight hours for the detection of natural biological materials present in the ocean. The wide-area and video-speed imaging capabilities of CoCoBi for biodetection may be highly useful in future NASA rover-lander life detection missions.