Behavior Of Squid Research Articles

Control of the effective value of the critical current of the RF SQUID by the high-frequency electromagnetic field

An analysis of the influence of the high-frequency electromagnetic field on the amplitude-frequency and signal characteristics of RF SQUID and experimental verification are carried out. At low parameter βL, the RF SQUID behavior is well described analytically by the theoretical model. In experiment, basic operation scheme is used in which the interferometer is inductively connected to a resonant circuit driven by RF current at a frequency close to the resonance frequency of the circuit. It is shown that parameter βL, which distinguishes between hysteretic and nonhysteretic regimes, can be effectively adjusted to a desired value by applying the high-frequency field of a certain amplitude and frequency much higher than circuit resonance frequency. A significant increase in the conversion factor and sensitivity of the RF SQUID during this adjustment is discussed.

Approaching and Staying Behavior of Oval Squid, Sepioteuthis lessoniana, in Response to a State of Floated Squid Trap

Approaching and Staying Behavior of Oval Squid, <i>Sepioteuthis lessoniana</i>, in Response to a State of Floated Squid Trap

Changes in feeding behavior of longfin squid (Doryteuthis pealeii) during laboratory exposure to pile driving noise

Anthropogenic noise can cause diverse changes in animals' behaviors, but effects on feeding behaviors are understudied, especially for key invertebrate taxa. With the offshore wind industry expanding, concern exists regarding potential impacts of pile driving noise on squid and other commercially and ecologically vital taxa. We investigated changes in feeding and alarm (defense) behaviors of squid, Doryteuthis pealeii, predating on killifish, Fundulus heteroclitus, during playbacks of pile driving noise recorded from wind farm construction within squids' habitat. Fewer squid captured killifish during noise exposure compared to controls. Squid had more failed predation attempts when noise was started during predation sequences. Alarm responses to noise were similar whether or not squid were hunting killifish, indicating similar vigilance to threat stimuli in these contexts. Additionally, novel hearing measurements on F. heteroclitus confirmed they could detect the noise. These results indicate noise can disrupt feeding behaviors of a key invertebrate species, and will leverage future studies on how noise may disrupt squids’ vital ecological interactions.

What is on the menu? Feeding, consumption and cannibalism in exploited stocks of the jumbo squid Dosidicus gigas in south-central Chile

Only few studies on the feeding and cannibalism behavior of the jumbo squid have been conducted in the Humboldt Current System despite this species is currently considered an important economic resource. It is possible that the diet of this ommastrephid squid varies throughout the year, among areas and body size. Therefore, we herein collected jumbo squids from commercial catches during January to December 2014 using purse-seine nets. The stomach contents were analyzed in terms of frequency of occurrence, number, and weight of prey items. The diet composition was analyzed using Detrended Correspondence Analysis. The variation of jumbo squid diet composition was evaluated from different biological and temporal predictors (sex, maturity, body size and months), considering and analyzing cannibalism. Daily ration was estimated using three methods to calculate consumption and consumption/biomass ratio. Our results suggest that there are significant differences in diet throughout the year, among sizes, and between sexes, however, no differences were found according to the interactions of these factors, except for the interaction between sex and month. In addition, significant differences were detected for each factor (sex, month and body size) when evaluating cannibalism, although these differences were only significant when factors were evaluated independently. Body size was the best predictor of diet composition, richness and cannibalism variation. Stomach content weight was highly biased due to the advanced level of digestion, which in turn biased the diet based on weight, daily ration and consumption analyses. In this sense, the bioenergetic model based on water temperature fitted better than models based on stomach content weight and body mass. These results showed that D. gigas mostly predates on crustaceans and cephalopods, which contrasts with most ecosystem models that suggest that this species highly predates on commercially-exploited fish species.

Jumbo squid behaviour in response to a rigid grid in the Chilean hake trawl fishery

Observations via underwater filming were obtained to improve understanding of the behavior and selection process of jumbo squid (Dosidicus gigas) in response to a rigid grid in the Chilean hake (Merluccius gayi gayi) trawl fishery in central Chile. The individual fates of jumbo squid were examined to study the efficiency of the selection system. The number of escaped versus captured specimens was quantified. During the selection process, we observed obstacles that impeded the escape process, leading to retention of jumbo squid and limiting the selectivity effectiveness. The analysis showed that 69.8% of jumbo squid escaped the net and 75.5% faced obstacles that generated retention in the sorting process. Longer retention times led to a saturation of the selection system. The target species was successfully selected by the sorting system, in which 87.1% of Chilean hake entered the codend through the grid. We discuss the need to redesign components of the selection system to improve efficiency.

Quantifying the swimming gaits of veined squid (Loligo forbesii) using bio-logging tags.

Squid are mobile, diverse, ecologically important marine organisms whose behavior and habitat use can have substantial impacts on ecosystems and fisheries. However, as a consequence in part of the inherent challenges of monitoring squid in their natural marine environment, fine-scale behavioral observations of these free-swimming, soft-bodied animals are rare. Bio-logging tags provide an emerging way to remotely study squid behavior in their natural environments. Here, we applied a novel, high-resolution bio-logging tag (ITAG) to seven veined squid, Loligo forbesii, in a controlled experimental environment to quantify their short-term (24h) behavioral patterns. Tag accelerometer, magnetometer and pressure data were used to develop automated gait classification algorithms based on overall dynamic body acceleration, and a subset of the events were assessed and confirmed using concurrently collected video data. Finning, flapping and jetting gaits were observed, with the low-acceleration finning gaits detected most often. The animals routinely used a finning gait to ascend (climb) and then glide during descent with fins extended in the tank's water column, a possible strategy to improve swimming efficiency for these negatively buoyant animals. Arms- and mantle-first directional swimming were observed in approximately equal proportions, and the squid were slightly but significantly more active at night. These tag-based observations are novel for squid and indicate a more efficient mode of movement than suggested by some previous observations. The combination of sensing, classification and estimation developed and applied here will enable the quantification of squid activity patterns in the wild to provide new biological information, such as in situ identification of behavioral states, temporal patterns, habitat requirements, energy expenditure and interactions of squid through space-time in the wild.

Design and test of a grid to reduce bycatch in the longfin inshore squid (Doryteuthis pealeii ) trawl fishery

A species separation grid was tested for a squid trawl to reduce finfish bycatch in the Nantucket Sound longfin inshore squid (Doryteuthis pealeii) fishery in southern New England, USA. The experimental trawl with a grid significantly reduces bycatch of summer flounder (Paralichthys dentatus) (76.4%, p < .001), black sea bass (Centropristis striata) (71.7%, p = .001), smooth dogfish (Mustelus canis) (86.0%, p < .001), and total bycatch (69.2%, p < .001) when compared to a conventional trawl. The catch rate of scup (Stenotomus chrysops) is 40.2% less than in the experimental trawl, but this difference is not statistically significant (p = .258). However, the experimental trawl also reduces targeted squid capture by 47.5% (p < .001), which is commercially unacceptable. Length analysis indicates no size effect on the retention for squid between the trawl with a grid (experimental) and the one without a grid (control), but the experimental trawl significantly reduces larger scup (>27 cm FL) and larger black sea bass (>37 cm TL), and all summer flounder size-classes. Therefore, this grid design may not be a suitable bycatch reduction device for the Nantucket Sound squid trawl fishery, and further work is needed to understand squid behavior within a trawl to develop a successful bycatch reduction strategy for the New England longfin inshore squid fishery.

Multi target positioning system using Gold code pingers applied to Japanese squid in Japan Sea

To study the effect of light on Japanese squid (Todarodes pacificus) behavior, we developed a new ultrasonic biotelemetry system that can simultaneously observe and measure multiple targets. We tested the system on 40 squids in open water. Each squid was attached with a Gold code pinger (AquaSound Inc.) that transmits single frequency signals of multiple codes (IDs). By using the combination of 32 kinds of Gold code sequences, we succeeded to develop a receiving system that can simultaneously track 40 pingers. In the field test, 40 squids attached with the Gold code pingers were released simultaneously into open water and signals were recorded from three fishing boats for a maximum of six hours. The underwater positioning of the squids was calculated based on the “reverse cross-bearing” method by using the cross points from each direction against the target obtained by two boats. With the addition of depth data obtained by the pressure sensor installed in each Gold code pinger, we succeeded to measure the 3D positions of all 40 target squids. Considering the movement of boats by wind and tide, the positions of all three boats were measured every second using the GNSS (FURUNO Electronics Co., Ltd.).

Anti-predator behavior of squid throughout ontogeny

Squid utilize an array of complex anti-predator behaviors, which provide advantages to avoid high predation pressure. Although there are morphological and ecological differences among paralarval, juvenile and adult squid, no studies have examined how anti-predator behavior changes through life history stages in cephalopods. The goal of this study was to (1) document how anti-predator behavior in squid changes throughout ontogeny and (2) measure kinematic variables associated with squid-predator interactions to analyze the behavioral cues that trigger anti-predator responses. Anti-predator responses in squid were studied in a series of predator-prey trials using high-speed videography. All life histories of squid exhibited some escape jetting in response to predators, but paralarvae exhibited far fewer escape responses relative to juveniles and adults, and did not demonstrate posturing or inking behavior. For 65% of the interactions, paralarvae used stereotyped behaviors such as swimming in repetitive circles and spirals, rather than escape jetting, and clear body patterning during predator encounters. Inking responses in juveniles and adults were associated with significantly higher predator approach velocities and closer predator-squid distances when compared with postural responses. Older squid were more likely to demonstrate the banded body pattern, and the ‘pseudomorph’ ink shape was most commonly used. The observed differences in anti-predator behavior throughout ontogeny indicate that paralarvae rely on stereotyped swimming behaviors and translucent coloration to avoid capture, while juvenile and adults use kinematic cues of the predator approach to determine whether posturing, inking and escape jetting, or a combination of the two is the most suitable anti-predator behavior.

Fish and squid behaviour at the mouth of a drop-chain trawl: factors contributing to capture or escape

Abstract Underwater video recordings in the mouth of a squid trawl were used to evaluate the effectiveness of a trawl configured with drop-chain groundgear to catch longfin inshore squid (Doryteuthis pealeii) and reduce bycatch of finfish in the Nantucket Sound squid fishery off Cape Cod, Massachusetts, USA. Entrance through the trawl mouth or escape underneath the fishing line and between drop chains was quantified for targeted squid, and two major bycatch species, summer flounder (Paralichthys dentatus) and skates (family Rajidae). Additionally, contact and impingement between animals and groundgear were also quantified. Fish and squid swimming behaviours, positions, orientations, and time in the trawl mouth were quantified and related to capture or escape at the trawl mouth. Squid entered the trawl singly and in schools, and no squid were observed escaping under the fishing line. Most squid entered the trawl in the upper portion of the trawl mouth; mantle orientated away from the trawl and swimming in the same direction, and were gradually overtaken, not actively attempting to escape. Summer flounder and skates were observed to remain on or near the seabed, orientated, and swimming in the same direction as the approaching trawl. The majority (60.5%) of summer flounder entered the trawl above the fishing line. Summer flounder that changed their orientation and turned 180° were significantly more likely to enter the trawl (p &amp;lt; 0.05). Most skates (89.7%) avoided trawl entrance and escaped under the fishing line. Neither squid nor summer flounder were observed to make contact or become impinged to the groundgear; however, 35.4% of skates had substantial contact with groundgear, with 12.3% becoming impinged. Video analysis results showed that the drop-chain trawl is effective at retaining targeted squid while allowing skates to escape. However, it is ineffective at avoiding the capture of summer flounder.

Josephson systems based on ballistic point contacts between single-band and multi-band superconductors

The Josephson effect in ballistic point contacts between single-band and multi-band superconductors was investigated. It was found that in the case of Josephson junctions formed by a single-band and an s±-wave two-band superconductor as well as by a single-band and a three-band superconductor the junctions become frustrated, showing the φ-contact properties. Depending on the ground state of a three-band superconductor with time-reversal symmetry breaking, the Josephson junction can have from one to three energy minima, some of which can be locally stable. We also study the behavior of a dc SQUID based on the Josephson junctions between single-band and multi-band superconductors. Some features on the dependences of the critical current and the total magnetic flux on the applied flux of a dc SQUID based on the Josephson point contacts between a single-band superconductor and an s±-wave superconductor, three-band superconductor with broken time-reversal symmetry and three-band superconductor without broken time-reversal symmetry as compared to the conventional dc SQUIDs based on single-band superconductors were found. The results can be used as an experimental tool to detect the existence of multi-band structure and time-reversal symmetry breaking.

Numerical Simulation of DC SQUID Taking Into Account Quantum Characteristic of Josephson Junction

High-temperature superconducting quantum interference devices (HTS SQUIDs) have been developed as an extremely sensitive magnetic sensor. The HTS SQUIDs are required to have high robustness with respect to the magnetic noise for stable operation in an unshielded environment and also reduced cost to widen the application range. It is, therefore, necessary to clarify the quantum magnetic behavior of the HTS SQUID. However, a simulation tool, which can consider the quantum magnetic behavior, has not been developed yet. In this paper, an equivalent circuit of a Josephson junction comprising the HTS SQUID is more properly considered to represent the quantum behavior. It can consider the ac and dc Josephson effect. The obtained results are compared with an ordinary simulation using a simplified circuit model, and the results agree well with each other. Using the proposed simulation method instead of the ordinary simulation, the current path is more accurately simulated, so this new method will be used to evaluate the robustness of the SQUID.

Injury shapes squid behaviour

Injury shapes squid behaviour

Numerical Simulation of SQUID Magnetometer Considering Equivalent Electrical Circuit of Josephson Junction

A SQUID is a highly sensitive magnetic sensor. However, a defect of SQUID is high susceptibility to magnetic noise. The high robustness of SQUID with respect to magnetic noise enables to widen the range of applications. We have striven to clarify the mechanism of weakness in magnetic noise by means of numerical electromagnetic field simulation to support a SQUID development. However, a Josephson junction was modeled as a constant resistance and a SQUID behaviour was not correctly simulated in the previous paper. Therefore, the non-linear current-voltage characteristic of the Josephson junction is newly taken into account the simulation to represent the SQUID behaviour. As the results, the phenomena of the step-increasing magnetic flux and the spike voltage that could not be reproduced in the previous paper is simulated. It is successful to qualitatively evaluate the SQUID behaviour, i.e. it becomes possible to represent superconducting-to-voltage and voltage-to-superconducting state transitions.

Quantitative analysis of the behavior of longfin inshore squid (Doryteuthis pealeii) in reaction to a species separation grid of an otter trawl

Underwater video recording of the behavior of longfin inshore squid (Doryteuthis pealeii) in response to a Nordmøre-style finfish bycatch reduction grid installed in the extension of a trawl was made during experimental fishing in Nantucket Sound off Cape Cod, Massachusetts, USA. Swimming and jetting behavior, time in trawl extension, position, and orientation of squid were quantified in relation to capture by, or escape from, the trawl. Squid actively avoided the grid and escaped by jetting and changing directions. Few squid became stuck on the grid (6.4%), the majority of which eventually passed between the grid spacings and entered the codend (83.9%). Squid that passed through the grid spent less time before the grid, and were less likely to jet or change directions (p<0.05). Squid that approached the grid from the top of the extension, and with mantle oriented toward the grid, were more likely to be caught (p<0.05). The potential for taking advantage of these behaviors in response to a grid is discussed in relation to improving techniques for separating squid from finfish bycatch in the squid trawl fishery.

Oceanic squid do fly

Using powerful jet propulsion, some squid species are able to exit the water and become airborne; this is a common behavior seen throughout the world’s oceans. However, direct scientific observation is rare, with most studies relying on anecdotal evidence and limited photographic documentation. Here, we examine the flying behavior of young oceanic squid (Ommastrephidae) observed in sequential photographs taken in the Northwest Pacific (35o34.0′N, 146o19.3′E) on July 25, 2011. We define four phases in the flight process: launching, jetting, gliding and diving. During flight, squid actively change their aerial posture and attitude depending on the flight phase and their distance from the water. The present study demonstrated that flight of squid is not simple gliding after incidental exit from the water, but involves jet propulsion, generation of lift force and control of different body postures in different flight phases, which have evolved to enhance escape from predators.

Mating Behavior of a Deep-Sea Squid Revealed by in situ Videography and the Study of Archived Specimens

The mating behavior of deep-sea squids is shrouded in mystery. The squids for which mating has been observed use a hectocotylus, a modified arm, for the transfer of sperm packets called spermatophores. However, many deep-sea squid species lack a hectocotylus. We present the first in situ observations of mating behavior in a deep-sea squid that has no hectocotylus but instead uses an elongated terminal organ for the transfer of spermatangia, which are released from the spermatophores and burrow deeply into the female tissue. With remotely operated vehicles (ROVs), we observed two mating pairs of the deep-sea squid Pholidoteuthis adami in the Gulf of Mexico. The male adopted a peculiar position during mating, with its ventral side up and its posterior mantle above the female’s head. While the male held the female in what looked like a firm grip, we observed the long terminal organ extending through the funnel of the male, contacting the female dorsal mantle. Examinations of museum specimens show that spermatangia burrow from the outer dorsal mantle into the inner dorsal mantle. This combination of serendipitous in situ observations and archived specimens can be a powerful tool for understanding the behavior of deep-sea animals.

Locomotion and behavior of Humboldt squid,Dosidicus gigas, in relation to natural hypoxia in the Gulf of California, Mexico

We studied the locomotion and behavior of Dosidicus gigas using pop-up archival transmitting (PAT) tags to record environmental parameters (depth, temperature and light) and an animal-borne video package (AVP) to log these parameters plus acceleration along three axes and record forward-directed video under natural lighting. A basic cycle of locomotor behavior in D. gigas involves an active climb of a few meters followed by a passive (with respect to jetting) downward glide carried out in a fins-first direction. Temporal summation of such climb-and-glide events underlies a rich assortment of vertical movements that can reach vertical velocities of 3 m s(-1). In contrast to such rapid movements, D. gigas spends more than 80% of total time gliding at a vertical velocity of essentially zero (53% at 0±0.05 m s(-1)) or sinking very slowly (28% at -0.05 to -0.15 m s(-1)). The vertical distribution of squid was compared with physical features of the local water column (temperature, oxygen and light). Oxygen concentrations of ≤20 μmol kg(-1), characteristic of the midwater oxygen minimum zone (OMZ), can influence the daytime depth of squid, but this depends on location and season, and squid can 'decouple' from this environmental feature. Light is also an important factor in determining daytime depth, and temperature can limit nighttime depth. Vertical velocities were compared over specific depth ranges characterized by large differences in dissolved oxygen. Velocities were generally reduced under OMZ conditions, with faster jetting being most strongly affected. These data are discussed in terms of increased efficiency of climb-and-glide swimming and the potential for foraging at hypoxic depths.

Diving into the analysis of time–depth recorder and behavioural data records: A workshop summary

Directly observing the foraging behavior of animals in the marine environment can be extremely challenging, if not impossible, as such behavior often takes place beneath the surface of the ocean and in extremely remote areas. In lieu of directly observing foraging behavior, data from time–depth recorders and other types of behavioral data recording devices are commonly used to describe and quantify the behavior of fish, squid, seabirds, sea turtles, pinnipeds, and cetaceans. Often the definitions of actual behavioral units and analytical approaches may vary substantially which may influence results and limit our ability to compare behaviors of interest across taxonomic groups and geographic regions. A workshop was convened in association with the Fourth International Symposium on Bio-logging in Hobart, Tasmania on 8 March 2011, with the goal of providing a forum for the presentation, review, and discussion of various methods and approaches that are used to describe and analyze time–depth recorder and associated behavioral data records. The international meeting brought together 36 participants from 14 countries from a diversity of backgrounds including scientists from academia and government, graduate students, post-doctoral fellows, and developers of electronic tagging technology and analysis software. The specific objectives of the workshop were to host a series of invited presentations followed by discussion sessions focused on (1) identifying behavioral units and metrics that are suitable for empirical studies, (2) reviewing analytical approaches and techniques that can be used to objectively classify behavior, and (3) identifying cases when temporal autocorrelation structure is useful for identifying behaviors of interest. Outcomes of the workshop included highlighting the need to better define behavioral units and to devise more standardized processing and analytical techniques in order to ensure that results are comparable across studies and taxonomic groups.

Acoustic estimation of effective gathering range of shipboard fishing light for squid jigging

The effective range of fishing light for the Japanese common squid jigging was investigated using acoustic methods in the Japan Sea on August 21- 24, 2011. The research vessel collected acoustic signals of a sonar and a quantitative echosounder from squid around the jigging boat equipped with metal halide lamps. Digital images of sonar echogram were composed to make maps which can be used to measure locations, sizes, and relative echo intensity of squid school. Behavior of individual squid was observed by an acoustic tag. The receiver was prepared on each vessel. The tag was attached on a fin of squid onboard the research vessel. Total 22 tagged squids were released from the research vessel in three nights and the distance between the vessels at release time ranged from 0.25 to 1.1 nmi. Total 7 squids were received at the jigging boat after 1 - 3 hours from their release. The distance between vessels at release time ranged 0.25 to 0.7 nmi. The squids which were released within 0.5 or 0.6 nmi were received at the jigging boat in every night. From these results, the effective gathering range of the fishing light was estimated to be at least 0.5 nmi.