Deep-sea Squid Research Articles

Giant eggs in a deep-sea squid.

Giant eggs in a deep-sea squid.

Сравнительный анализ эффективности новых образцов местных гемостатических средств

Various local hemostatics (based on collagen, gelatin, cellulose, etc.) are used to stop bleeding from parenchymal organs of the abdominal cavity. In the context of an acute in vivo experiment, this study aimed to comparatively assess the time and volume of bleeding from a trauma of abdominal cavity's parenchymal organs covered with a new collagen-based spongy hemostatics combined with Na-CMC. We used new multicomponent polymer sponge implants (MPSI) based on marine collagen and carboxymethyl cellulose sodium salt, Na-CMC; the components were mixed in the ratios of 15/85, 25/75, 50/50. Hemostatic activity of the samples was assessed by bleeding time and blood loss volume. For the experiments, rats underwent laparotomy and resection of the left lobe of liver (series 1) and lower pole of spleen (series 2). In both series of experiments, the controlled parameters (bleeding time and blood loss volume) were smallest in group 6, where the MPSI were 50/50 Na-CMC/collagen. The hypothesis of higher efficacy of composite local hemostatic agents (namely, made of Na-CMC and deep-sea squid collagen) in cases of trauma of the parenchymal organs was confirmed experimentally, and same experiment has also shown that collagen in the composition of MPSI boosts bleeding arrest (for liver injury, the smallest blood loss and hemorrhage control time was 41 s, for spleen injury — 57 s, respectively; p ≤ 0.05).

Towards unlocking the trophic roles of rarely encountered squid: Opportunistic samples of Taningia danae and a Chiroteuthis aff. veranii reveal that the Southern Ocean top predators are nutrient links connecting deep-sea and shelf-slope environments

Deep-sea squids are presumably vital components of largely undescribed marine ecosystems, yet limited access to specimens has hampered efforts to detail their ecological roles as predators and preys. Biochemical techniques such as stable isotope analyses, fatty acid analyses, and bomb calorimetry are increasingly recognized for their ability to infer trophic ecology and dietary information from small quantities of tissue. This study used five opportunistically collected Taningia danae specimens and one Chiroteuthis aff. veranii specimen retrieved from the Great Australian Bight, South Australia, to detail the trophic ecology of these poorly understood squids. Four body tissue types (i.e., arm, buccal mass, mantle, and digestive gland) were assessed for their utility in stable isotope (SI) and fatty acid (FA) analyses, and we found that the arm, buccal mass, and mantle tissues had similar SI and FA profiles, suggesting that they can be used interchangeably when the entire specimen is unavailable. δ13C, δ15N, and fatty acid data suggests that the T. danae and C. aff. veranii specimens lived in the Southern Ocean and were high-trophic-level predators, feeding on deep-sea fishes and small squids, while also taking advantage of the summer upwelling region of the Great Australian Bight. The fatty acid analysis and bomb calorimetry results indicate that these squids might be important reservoirs of essential FAs (EPA and DHA) for Southern Ocean predators and that the whole-body energy content of T. danae individuals can reach up to 362,250 kJ. Our findings indicate that these squids may be contributing greatly to the transport of nutrients and energy between the Southern Ocean deep-sea and the Great Australian Bight shelf–slope environments. In addition to building our understanding of the trophic ecology of two poorly understood deep-sea squids, these findings also highlight the utility of partial specimens and demonstrate the important ecological information that can be obtained from few samples that may be opportunistically collected.

Influence of ocean dynamics on Cuvier’s beaked whale (Ziphius cavirostris): Presence and their prey

Cuvier’s beaked whales (Ziphius cavirostris; Zc) dive below 1000 m to forage predominantly on deep-sea squids. The impact of oceanographic conditions on Zc prey and the effects of anthropogenic sounds on Zc foraging remain unclear. Zc prey distribution is patchy and potentially influenced by mesoscale oceanographic features interacting with local bathymetry. Favorable environmental conditions lead to aggregations of lower trophic level species that attract squid, and potentially increase Zc presence. We collected simultaneous active and passive acoustic data in Tanner Basin, a southern California submarine canyon, intermittently between 2017 and 2022. Passive acoustic data revealed Zc were present throughout all years, with lower presence during late summer and fall. Subsurface Zc 3D track reconstructions indicated a preference for one side of the canyon, where Zc foraged within a layer of potential prey, detected from active acoustic data. Prey concentrations, quantified as volume backscatter strength below ∼1150 m depth, exhibited an increase following the passage of mesoscale features, which were measured using Finite-size Lyapunov Exponents (FSLE). These prey increases drove immediate increases in Zc presence. Understanding potential physical drivers of Zc predator-prey dynamics is a critical first step for assessing natural variability and potential impacts of sonar use on Zc foraging behavior.

Trophic ecology of the deep-sea squid Moroteuthopsis ingens (Cephalopoda: Onychoteuthidae) from the Chatham Rise, Aotearoa New Zealand

ABSTRACT Cephalopods form important components of marine trophic systems worldwide, including those in the South Pacific. Moroteuthopsis ingens (Onychoteuthidae) is one of the most abundant deep–sea squids in the Aotearoa New Zealand region and is preyed upon by predators such as the sperm whale and orange roughy. However, despite the many publications on M. ingens’ diet, knowledge on its feeding ecology remains limited. In this study, we analysed the prey of M. ingens from the Chatham Rise (an ecologically and economically important region east of Te Waipounamu/New Zealand’s South Island) using DNA barcoding and otolith identification. Lanternfishes (Myctophidae) were the most frequently encountered prey item, but other teleost species, cephalopods and crustacean fragments were also found, indicating opportunistic and likely cannibalistic feeding behaviour. Five fish species (including a possibly undescribed species of Gymnoscopelus) and Bathyteuthis abyssicola are reported as prey items of M. ingens for the first time. Moroteuthopsis ingens appears to be a component of several dynamic food chains and likely plays an important role in the transfer of carbon throughout marine environments in the Southern Hemisphere.

Deep sea squid in Sulawesi Sea, North Sulawesi Province, Indonesia

Abstract. Pratasik SB, Lalamentik LTHX, Manoppo L, Budiman J. 2022. Deep sea squid in Sulawesi Sea, North Sulawesi Province, Indonesia. Biodiversitas 23: 1774-1779. This study aimed to identify one of the deep sea squids caught in artisanal fisheries by traditional fishermen in Sulawesi Sea, North Sulawesi Province, Indonesia. Samples were collected using the vertical hand line of traditional fishermen. The specimen was identified using Cytochrome c oxidase subunit 1 (CO1). For morphometric characteristics, all body parts were measured, and each part was compared with mantle size. Results showed that the specimen was identified as purpleback flying squid Sthenoteuthis oualaniensis and had 99.35% similarity to S. oualaniensis (CO1) from China (NCBI - MN101944) with sufficient genetic diversity. Based on the body size, species recorded in the present study belong to the dwarf form, the smallest form of S. oualaniensis groups. The species has the following morphometric characteristics: Head length is 0.28 of mantle length, tentacle length is 1.158 of mantle length, and fin area is 0.5 of mantle length. The fourth arm is the shortest and the second arm is the longest. S. oualaniensis recorded in the present study belonged to dwarf form living in equatorial waters. This finding may contribute to the list of marine resources of fisheries in Indonesian waters.

Studying the swift, smart, and shy: Unobtrusive camera-platforms for observing large deep-sea squid

The legend of the “kraken” has captivated humans for millennia, yet our knowledge of the large deep-sea cephalopods that inspired this myth remains limited. Conventional methods for exploring the deep sea, including the use of nets, manned submersibles, and remotely operated vehicles (ROVs), are primarily suited for studying slow-moving or sessile organisms, and baited camera-traps tend to attract scavengers rather than predators. To address these issues, unobtrusive deep-sea camera platforms were developed that used low-light cameras, red illuminators, and bioluminescence-mimicking lures. Here, we report on several opportunistic deployments of these devices in the Wider Caribbean Region where we recorded several encounters with large deep-sea squids, including the giant squid Architeuthis dux Steenstrup 1857, Pholidoteuthis adami Voss 1956, and two large squid that may be Promachoteuthis sp. (possibly P. sloani Young et al. 2006). These species were recorded between depths of 557 and 950 m. We estimate the Mantle Lengths (ML) of Promachoteuthis were ~1.0 m, the ML of the Pholidoteuthis was ~0.5 m, and the ML of the Archtiteuthis was ~1.7 m. These encounters suggest that unobtrusive camera platforms with luminescent lures are effective tools for attracting and studying large deep-sea squids.

Insights into the role of deep-sea squids of the genus Histioteuthis (Histioteuthidae) in the life cycle of ascaridoid parasites in the Central Mediterranean Sea waters

Ascaridoid nematodes comprise a wide range of heteroxenous parasites infecting top fish predators and marine mammals as definitive hosts, with crustaceans, squids, and fishes acting as intermediate/paratenic hosts. Limited data exist on the species and role of several intermediate and paratenic hosts in the life cycle of these parasites. In the aim of adding knowledge on the role of squid species in their life cycle, we have here investigated the larval ascaridoid nematodes collected from the deep-sea umbrella squid Histioteuthis bonnelli and the reverse jewel squid Histioteuthis reversa captured in the Central Mediterranean Sea (Tyrrhenian Sea). Morphological study and sequence analysis of the internal transcribed spacer (ITS) regions of the ribosomal DNA (rDNA) and the mitochondrial cytochrome c oxidase subunit 2 (mtDNA cox2) gene locus revealed the occurrence of Anisakis physeteris and of an unidentified species of the genus Lappetascaris. Sequence analysis revealed that specimens of Lappetascaris from both squid species matched at 100% sequences previously deposited in GenBank from larval ascaridoids collected in octopuses of the genus Eledone of the Mediterranean Sea. The Bayesian inference tree topology obtained from the analysis of the fragments amplified showed that Lappetascaris specimens were included in a major clade comprising Hysterothylacium species collected in fishes of the families Xiphiidae and Istiophoridae. As regards the site of infection in the squid host species, A. physeteris larvae predominated (60.7%) in the gonads, while those of Lappetascaris (76.3%) were found infecting the mantle musculature. The overall high values of parasitic load suggest both squid species as transmitting hosts of third stage larvae of Lappetascaris to top predator fishes, as well as the umbrella squid as an intermediate/paratenic host in the life cycle of A. physeteris in the Mediterranean Sea.

Actual fecundity of the Arctic squid Gonatus fabricii (Cephalopoda) based on the examination of a rarely encountered spent female

ABSTRACT Gonatus fabricii (Lichtenstein, 1818) is an ecologically important squid that spends its entire life cycle within the Arctic where it is the most abundant cephalopod. Due to the rarity of mature and reproducing females, it is unknown how many eggs females spawn (actual fecundity). Among 47,000 specimens studied between 2005 and 2019 one spent, degenerated and gelatinous female with a mantle length of 230 mm was caught in West Greenland in 2019. Examination allowed the first detailed description of fecundity and spawning pattern in the species. Oocyte development shows that the most considerable maturation of mid-vitellogenic oocytes to late vitellogenic and then to ripe stages occurs immediately after the first ripe oocytes appear in the ovary. There were no ripe oocytes in the ovary or oviducts. The ovary contained an estimated 6561 oocytes and 2551 post-ovulatory follicles and hence the total fecundity was 9112. This specimen of G. fabricii realised 28.0% of its potential fecundity which is comparable to Berryteuthis magister, which also belongs to Gonatidae, and lower than in the majority of studied deep-sea squids (including other gonatids). Spent females may provide clues as to where the major spawning areas of this abundant but poorly known squid are located.

Is there more than one species in the genusSpirula(Cephalopoda: Decabrachia): evidence for an Atlantic–Pacific divide

ABSTRACTSpirula spirula (Coleoidea: Decabrachia) is a unique deep-sea squid with an uncertain taxonomic status. Here, we apply geometric morphometric analyses to precisely describe changes in conch morphology during the course of ontogeny of 21 specimens collected from 12 localities worldwide. These data were used to explore whether the genus is monospecific or comprises several species. Different 2D and 3D conch parameters are presented based on micro-computed tomography data, combining noninvasive imaging techniques with a range of morphometric analyses. Our data imply that Atlantic and Indo-Pacific specimens form two distinct morphological clusters, potentially representing two pseudocryptic species or two populations undergoing divergence (i.e. in the process of speciation). Given the evolutionary trend from straight to more coiled forms, we suggest that S. spirula represents a neotenous form that migrated from the Indo-Pacific towards the Atlantic via the Agulhas leakage, which has been active since the closure of the Strait of Panama (10–3 Ma).

Multiple observations of Bigfin Squid (Magnapinna sp.) in the Great Australian Bight reveal distribution patterns, morphological characteristics, and rarely seen behaviour.

One of the most remarkable groups of deep-sea squids is the Magnapinnidae, known for their large fins and strikingly long arm and tentacle filaments. Little is known of their biology and ecology as most specimens are damaged and juvenile, and in-situ sightings are sparse, numbering around a dozen globally. As part of a recent large-scale research programme in the Great Australian Bight, Remotely Operated Vehicles and a towed camera system were deployed in depths of 946–3258 m resulting in five Magnapinna sp. sightings. These represent the first records of Bigfin Squid in Australian waters, and more than double the known records from the southern hemisphere, bolstering a hypothesis of cosmopolitan distribution. As most previous observations have been of single Magnapinna squid these multiple sightings have been quite revealing, being found in close spatial and temporal proximity of each other. Morphological differences indicate each sighting is of an individual rather than multiple sightings of the same squid. In terms of morphology, previous in-situ measurements have been roughly based on nearby objects of known size, but this study used paired lasers visible on the body of a Magnapinna squid, providing a more accurate scaling of size. Squid of a juvenile size were also recorded and are confirmed to possess the long distal filaments which have thus far been mostly missing from specimens due to damage. We have described fine-scale habitat, in-situ colouration, and behavioural components including a horizontal example of the ‘elbow’ pose, and coiling of distal filaments: a behaviour not previously seen in squid. These sightings add to our knowledge of this elusive and intriguing genus, and reinforce the value of imagery as a tool in deep-sea squid research.

Mechanical properties of high density polyethylene matrix composites reinforced with chitosan particles

High Density Polyethylene (HDPE) matrix composites reinforced with chitosan particles were developed by compression moulding technique. Chitosan particles extracted from deep sea squid with 90% deacetylation, bulk density of 0.3 g/cm3 and particle size of 90 μm were used as reinforcement. HDPE and various weight fractions (2, 4, 6, 8 and 10 wt%) of chitosan particles were melt-compounded in a single screw laboratory extruder with rotational speed of 50 rpm and temperatures of 190–220 °C. The blends were then moulded into different test specimens using carver laboratory press at a temperature of 230 °C for 12 min under applied pressure of 0.2 kPa. The mechanical properties (flexural, tensile and impact) of the developed composites were studied. The results showed that there were improvements in the mechanical properties of the composites. The optimal values for the tensile strength and tensile modulus of the composites were observed at 2 wt% chitosan particles reinforcement with values of 23.14 MPa and 828.38 MPa respectively while that of flexural strength and flexural modulus were noticed at 4 wt% with values of 83.90 MPa and 1690 MPa respectively. The impact strength of the composites increased linearly from 2 to 10 wt% Chitosan particles reinforcement with an optimum value of 229.20 KJ/m2. The scanning electron microscope (SEM) examination of the composites revealed that there were homogeneous particles dispersion at lower weight fractions (2–6 wt%) while particles agglomerations were noticed on the SEM images at higher weight fractions (8–10 wt%).

A description of three new bathyteuthid squid species from the North Atlantic and Gulf of Mexico

Currently, three species in the squid family Bathyteuthidae are recognized as valid: Bathyteuthis abyssicola Hoyle, 1885, Bathyteuthis bacidifera Roper, 1968, and Bathyteuthis berryi Roper, 1968. Using morphology and DNA sequencing (COI, 16S), we discovered three additional species of bathyteuthids collected from the North Atlantic Ocean and adjacent basins between 2009 and 2018. Two of the newly discovered species share the absence of arm-base photophores as well as differences in arm-sucker and buccallappet sucker counts. In the third species, the adult female individual has arm-base photophores but the two juveniles (sex undetermined) do not. All examined individuals of this species exhibited <1% divergence rate for the COI locus. We describe and name the three new species based on both morphological and molecular characters.

Critical threshold identified in the functional relationship between beaked whales and their prey

Anthropogenic noise is increasingly recognized as a potentially significant stressor for marine animals. Beaked whales, deep-diving cephalopod predators, have been disproportionally present in atypical mass stranding events coincident with military sonar exercises, while frequently disturbed populations that do not strand may have reductions in fitness. We presentin situmeasures of prey availability, a key factor affecting fitness, for 2 distinct populations ofMesoplodon densirostris: one on a US Navy range in The Bahamas and one nearby in an area less exposed to sonar. The variables most strongly correlated with beaked whale habitat use were related to the distribution of deep-sea squid (mode spacing, peak depth, and 100 m scale variability). All squid metrics were more favorable for beaked whales at the less exposed site than those on the range. To develop a generalized functional relationship between prey resources and beaked whale habitat use, data from The Bahamas were combined with comparable data from another Navy range and the larger beaked whale,Ziphius cavirostris. A power-law relationship was observed between a normalized metric of prey quality and whale habitat use. A critical threshold in prey characteristics, below which beaked whales appear unlikely to be successful, but above which small changes in resource availability enable large gains for predators, was observed. This implies that modest changes in the behavior of individual whales associated with disturbance can have consequential population effects. Our results elucidate the ecological realities of these elusive and sensitive beaked whales, and the importance of environmental context in effective spatial planning for the deep sea.

A taste for squid: the diet of sperm whales stranded in Greece, Eastern Mediterranean

Sperm whales (Physeter macrocephalus) inhabiting the world's oceans, prey mainly on cephalopods, but also feed on fish when found in higher latitudes. However, the feeding habits of endangered Mediterranean sperm whales have received little attention with thus far only two individuals analysed for their stomach contents. This study expands the available knowledge using analysis of the stomach contents from nine individuals stranded in Greece between 2005 and 2014. 48,166 prey remains were examined in total and 28,258 of them were identified to show that sperm whales fed on 18 prey species (17 cephalopods and one teleost) from 14 different families. 15 of these species were deep-sea squids, which are not presently targeted by fisheries. The most important prey species, both in terms of numerical abundance (%N) and abundance by weight (%W), was the oceanic squid Histioteuthis bonnellii (%N = 48.4, %W = 66.3) followed by H. reversa (%N = 28.4, %W = 13.8) and Octopoteuthis sicula (%N = 8.5, %W = 17.2). Calf sperm whales consumed smaller cephalopods of these three prey species than non-calves, probably because larger cephalopods are more difficult to catch. The vast majority of ingested cephalopods were gelatinous, slow-swimming and small. Therefore, sperm whales inhabiting the Greek Seas and likely the whole eastern Mediterranean Sea, appear to target prey that are easy to catch, but need to be consumed in great numbers to fulfil the energy requirements of the whales.

Mercury levels in Southern Ocean squid: Variability over the last decade

The concentrations of total and proportions of organic mercury were measured in tissues of 355 individuals of 8 species of Southern Ocean squid (Alluroteuthis antarcticus, Bathyteuthis abyssicola, Filippovia knipovitchi, Galiteuthis glacialis, Gonatus antarcticus, Kondakovia longimana, Psychroteuthis glacialis and Slosarczykovia circumantarctica). Squid were caught around South Georgia (Scotia Sea) during 5 cruises, between the austral summers of 2006/07 to 2016/17 to evaluate temporal changes in bioaccumulation and tissue partitioning. Total mercury concentrations varied between 4 ng g−1 and 804 ng g−1 among all tissues. Net accumulation of mercury in muscle with size was observed in A. antarcticus, B. abyssicola and P. glacialis, but no relationship was found for S. circumantarctica and lower concentrations were observed in larger individuals of G. glacialis. Muscle tissues had the highest mercury concentrations in the majority of species, except for F. knipovitchi for which the digestive gland contained highest concentrations. In terms of the percentage of organic mercury in the tissues, muscle always contained the highest values (67%–97%), followed by the digestive gland (22%–38%). Lowest organic mercury percentages were found consistently in the gills (9%–19%), suggesting only low levels of incorporation through the dissolved pathway and/or a limited redistribution of dietary organic mercury towards this tissue. Overall, results are indicative of a decreasing trend of mercury concentrations in the majority of analysed species over the last decade. As cephalopods are an important Southern Ocean trophic link between primary consumers and top predators, these changes suggest decreasing mercury levels in lower trophic levels and an alleviation of the mercury burden on higher predators that consume squid.

ROV Observations on Reproduction by Deep-Sea Cephalopods in the Central Pacific Ocean

Telepresence-enabled operations by remotely operated vehicles (ROVs) allow many researchers a unique perspective on morphology, behavior, and small-scale distributions of deep-sea animals. I present some examples of cephalopod natural history from recent ROV dives in the central Pacific Ocean. These examples include clues to reproductive behavior of deep-sea squids and cirrate “dumbo” octopods. During 7-12 March 2017, the ROV Deep Discoverer (D2) operating from NOAA Ship Okeanos Explorer recorded high-definition video of several squid in the genus Chiroteuthis. These included a mature male, a mature female, and a moribund squid identifiable as C. picteti. The female had obviously mated, with spermatangia implanted in many locations, and was holding in its arms another squid that appeared to be another Chiroteuthis. Considered together, these observations may indicate a deep-sea spawning aggregation and, possibly, sexual cannibalism. Another series of observations by D2 revealed eggs of cirrate octopods attached to octocorals. The remarkable thing about these observations was that in two of them (18 March and 4 May) the egg chorion had swollen and burst the external egg capsule. This may explain how the hatching embryo is able to escape from the tough protective coating secreted by the oviducal gland of cirrates but not secreted by the better-known incirrate octopods.

Reproductive strategies of deep-sea squid (Mastigoteuthidae, Chiroteuthidae, Batoteuthidae and Cranchiidae)

Reproductive systems of rare adult specimens of the deep-sea squid genera Chiroteuthis, Mastigoteuthis, Liocranchia, and Bathoteuthis were collected in 2006 and 2015 in the different research surveys in the Atlantic Ocean between 46°40′S and 17°11′N. Whole squids were preserved in 4% buffered formaldehyde solution, subsequently transferred into 70% ethanol and studied in laboratory condition providing initial observations on spawning pattern in these animals. The potential fecundity of Ch. cf. joubini was ~ 45,000–50,000, the maximum egg size was 1.6–1.7 mm, while those of M. agassizii were ~ 8000–16,000 and 1.7–1.9 mm respectively. A maturing female of B. skolops had ~ 4800 eggs of which some ~ 1200 were atretic. The ovary of a spent L. reinhardti contained ~ 116,500 post-ovulatory follicles and no residual egg. Mature females of Chiroteuthis and Mastigoteuthis had spematangia implanted externally in the mantle, whereas Liocranchia had a specialised spermatangia receptacle on the inside of the mantle. Reproductive adaptations of these genera are discussed in relation to spawning habits of other deep-sea squids. Synchronous ovulation was found to be a prevailing type of the gonad development with all eggs being spawned as a single batch, with ot without brooding. In some species, this single batch is not released at once but in several consequent portions exhibiting ‘extended synchronous’ spawning.

Systematics and biology of the blue lanternfish, Diaphus coeruleus from the south-eastern Arabian Sea

The paper presents the first detailed study on systematics, otolith structure and biology of Diaphus coeruleus, from the south-eastern Arabian Sea. The closely related and co-inhabiting species D. coeruleus and D. watasei are distinguished on the basis of morphometric, meristic and otolith characters. Analysis of gut content revealed that these fishes mainly feed on deep sea squids and shrimps. Six maturation stages of gonads are identified in males (immature, quiescent, mature, ripe, spawning and spent) and five stages (immature, quiescent, mature, ripening and spawning stages) in females. Overall sex ratio deviated in favour of males (1 male: 0.2 female) and the mean fecundity was 2150 ± 353 eggs. The length-weight relationship shows an overall isometric growth in males with N = 76 and b = 3.13 and for females with N = 17 and suggests negative allometric growth (b = 1.719). Otolith length (LO) and otolith weight (WO) are positively correlated to standard body length (LS) and body weight (BW).

Albatross-borne loggers show feeding on deep-sea squids: implications for the study of squid distributions

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 592:257-265 (2018) - DOI: https://doi.org/10.3354/meps12482 Albatross-borne loggers show feeding on deep-sea squids: implications for the study of squid distributions Bungo Nishizawa1,*, Takanori Sugawara2, Lindsay C. Young3, Eric A. Vanderwerf3, Ken Yoda2, Yutaka Watanuki1 1Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1, Minato, Hakodate, Hokkaido 041-8611, Japan 2Graduate School of Environmental Studies, Nagoya University, Furo, Chikusa, Nagoya, Japan 3Pacific Rim Conservation, 3038 Oahu Avenue, Honolulu, HI 96822, USA *Corresponding author: nishizawa@salmon.fish.hokudai.ac.jp ABSTRACT: How surface-feeding albatrosses feed on deep-sea squids has long been a mystery. We investigated foraging behavior during daylight hours of 20 Laysan albatrosses Phoebastria immutabilis breeding in Hawaii using GPS- and camera-loggers. The birds traveled to the North Pacific Transition Zone up to 600 km north of their breeding site. The camera images showed that Laysan albatrosses fed on large (~1 m body length), intact floating dead squids (6 events) and floating fragmented squids (10 events) over deep oceanic water (>2000 m) while they flew in a straight path without sinuous searching. Feeding events on squids were not observed during trips when fishing vessels were photographed and seemed to be distributed randomly and sparsely. Thus, this study suggests that Laysan albatrosses found large, presumably post-spawning, squids opportunistically while they were traveling during daylight hours. Although we did not find cetaceans in our surface pictures, we could not rule out the possibility that birds fed on squids, especially fragmented specimens, in the regurgitates of cetaceans at depth. This study demonstrates the usefulness of combining animal-borne GPS- and camera-loggers on wide-ranging top predators for studying the distribution of little known deep-sea squids and their importance in the diet of marine top predators. KEY WORDS: Phoebastria immutabilis · GPS-logger · Camera-logger · Taningia danae · Onykia robusta · Hawaiian Islands · Area-restricted search Full text in pdf format Supplementary material PreviousNextCite this article as: Nishizawa B, Sugawara T, Young LC, Vanderwerf EA, Yoda K, Watanuki Y (2018) Albatross-borne loggers show feeding on deep-sea squids: implications for the study of squid distributions. Mar Ecol Prog Ser 592:257-265. https://doi.org/10.3354/meps12482 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 592. Online publication date: March 29, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.