Todarodes Pacificus Research Articles

Comparative analysis of the physical and chemical properties of dried products "KalmaKS" from the skin of the Commander and Pacific squid

The modern system of high-quality nutrition for the population includes the use of natural compounds from secondary products of animal origin. In the course of scientific substantiation of using secondary products from the processing of cephalopods, dried products from the skin of Pacific (Todarodes pacificus) and Commander squid (Berryteuthis magister) have been studied, their protein and amino acid composition and functional and technological characteristics have been analyzed. In samples from the skin of the Pacific squid, a high content of glutamic and aspartic acids (8–10 %) is noted; in samples from the skin of the Commander squid – glycine (20 %), proline (10 %) and arginine. High indicators of solubility, water-holding capacity and stability of foam structures are due to the significant content of type I destructured collagen (in a sample from the skin of Commander squid), and hydrophilic amino acids and type III collagen fragments (in a product made from Pacific squid skin). Infrared drying of products promotes denaturation and gelatinization of collagen in the skin of Commander squid, which is confirmed by the brighter color characteristics of the samples and high moisture-binding capacity when the temperature rises to 40 and 60 °C; this fact indicates an increase in the hydrophilic properties of the products of destruction of collagen fractions. Products made from skin, which is a secondary product of squid processing, have high potential for use in the food industry as water-retaining, fat-binding, and fat-emulsifying components.

Classification of set-net fish catch volumes in Iwate Prefecture, Japan using machine learning with water temperature and current distribution images at migration depth

Efficient management of set-net fisheries can be achieved by predicting fish catches in advance. We aimed to estimate fish catch volumes using machine learning based on the data obtained from past set-net fisheries. We also suggested that the estimation can be conducted without the installation of special sensors, such as fish finders, sonars, and cameras, in the set nets. Therefore, a special feature of this study is the construction of a machine learning model using marine environmental images around the set net. In particular, the distribution images of water temperature and current at a certain water depth were applied to the model. In set-nets where migratory fish are caught, ocean data related to migration routes can be useful for estimation. The images used in this study included the water temperature at a depth of 100 m, absolute velocity at a depth of 50 m, and sea surface temperature for comparison. We then classified the fish catch into three classes as follows: chum salmon, yellowtail, and Japanese common squid in Iwate Prefecture, Japan. Consequently, our results achieved an accuracy of approximately 70–80% compared with the validation and test dataset with the water temperature at depths of 100 m. They showed higher accuracy than the sea surface temperature and absolute velocity at a depth of 50 m. This study indicates the usefulness of image-based classification for predicting the volumes of fish caught by set nets.

Population genetics of Todarodes pacificus (Cephalopoda: Ommastrephidae) in the northwest Pacific Ocean via GBS sequencing.

The common squid, Todarodes pacificus, is an important commercial species that inhabits the northwest Pacific Ocean, particularly the East Japan Sea, the Pacific coast of Japan, and the East China Sea. In this study, we chose 29 individuals from three areas: one type from the Sea of Japan and two types from the East China Sea. A total of 43,529 SNPs were obtained using genotyping-by-sequencing (GBS). Our analyses revealed low genetic diversity and genetic differentiation in each type. Heterozygote deficiency and inbreeding have caused this low level of genetic diversity. Population structure analysis indicated that the three types were genetically similar, which may be attributed to strong gene flow combined with the demographic history events during the last 2 million years. This new GBS application technique provides valuable information for the conservation of marine species genetics and could be useful for the effective management of this resource.

Relationship between moon age and catch of Japanese flying squid <i>Todarodes pacificus</i> in the squid jigging fishery in the offshore area of the Sea of Japan

Relationship between moon age and catch of Japanese flying squid <i>Todarodes pacificus</i> in the squid jigging fishery in the offshore area of the Sea of Japan

Recent update: collagen extraction from marine resources as a promising natural antiaging

Aging is a natural process that occurs in every human. Aging can be prevented or slowed down through the appropriate and suitable use of collagen as an anti-aging treatment. Collagen is typically derived from raw materials such as pig or cow bones/skin, but recently there have been frequent outbreaks of infectious diseases among livestock, prompting the exploration of raw materials sourced from the sea to address this issue and create promising collagen for anti-aging purposes. The objective of this literature review research is to explore the potential of collagen extracts from marine resources as an anti-aging solution through an examination of relevant literature, which can serve as a reference for future research. A systematic review method was employed by collecting data from various literature sources, including research journals published both nationally and internationally, which discuss various marine resources containing collagen with anti-aging properties. Based on the systematic review, several natural resources containing collagen with anti-aging properties were identified, including sea cucumbers (Holothuroidea sp.), milkfish (Chanos chanos), tilapia (Oreochromis niloticus), jellyfish (Rhopilema esculentum), starfish (Asterias pectinifera), mackerel (Decapterus macarellus), squid (Todarodes pacificus), silver carp (Hypophthalmichthys molitrix), and blue sharks (Prionace glauca).

Chocolate squid (Todarodes pacificus) bait reduces snow crab catch rates

This study evaluated the performance of chocolate squid (Todarodes pacificus) bait as a lower-cost alternative to traditional squid bait in a snow crab (Chionoecetes opilio) fishery in Eastern Canada. The results showed that pots with chocolate squid bait had significantly lower catch rates compared to pots with traditional squid bait. The chocolate squid bait significantly reduced the number of crabs caught per pot by 13.99% and the weight of crabs caught per pot by 2.88 kg. Although the chocolate squid bait is cheaper, the decrease in catch rates could require increased effort to reach individual quotas, which could lead to longer or more frequent fishing trips and more traps being fished, increasing fuel consumption and habitat disruption, resulting in negative environmental impacts. Finding alternative lower-cost baits that maintain catch rates remains a key priority for reducing operational costs and minimizing environmental impacts in the snow crab fishery.

A newly identified enzyme from Japanese common squid Todarodes pacificus has the ability to biosynthesize d-aspartate

Amino acids exist in two chiral forms, namely L and D. Although l-amino acids are predominant in vivo, certain limited circumstances have reported the usage of d-amino acids. d-aspartate (Asp), among them, plays crucial physiological roles in living organisms and is biosynthesized from L-Asp by the enzyme named aspartate racemase (AspRase). D-Asp is known to accumulate in large amounts in the nervous system of cephalopods. To understand the function of D-Asp in nervous system in more detail, it is necessary to elucidate its metabolic pathway; however, AspRase gene has not been identified in cephalopods as in the case of mammals. In this study, we successfully identified a novel gene encoding AspRase from the optic ganglion of Japanese common squid Todarodes pacificus. Our discovery of the squid AspRase challenges the prevailing assumption that AspRases across different animals share similar structures. Surprisingly, the squid AspRase is a unique enzyme that differs significantly from known AspRases, being structurally and phylogenetically related to aspartate aminotransferase (AST) and possessing both AspRase and AST activities. The optimum pH and temperature for AspRase activity using L-Asp as a substrate are approximately 7.0 and 20 °C, respectively. Moreover, we have found that AspRase activity is enhanced in the presence of 2-oxoacids. These findings have far-reaching implications for the understanding of enzymology and suggest that yet-to-be-identified mammalian AspRases may also be phylogenetically related to AST, rather than conventional AspRases. Furthermore, our results provide valuable insights into the evolution of the D-Asp biosynthetic pathway.

Comparative efficacy of different tenderizing agents and time on Physicochemical textural and organoleptic properties of squid (Todarodes pacificus) muscle.

This study aimed to investigate the chemical, physical, textural, and sensory properties of the squid (Todarodes pacificus) muscle during different tenderization agents (yeast, milk, and mineral water) and times (3, 6, 12, and 24 h). The results of the analyses showed that different treatments and their durations affected the dry matter, ash, lipid, and crude protein content of the squid. According to sodium dodecyl sulfate-polyacrylamide gel electrophoresis results, it was observed that there was a slight decrease in band intensities based on different treatments and their durations. However, no significant changes were observed in myosin actin and paramyosin bands. It was found that the hardness (359.7 N), cohesiveness (0.63), and gumminess (233.2 N) parameters increased at the 6th hour, decreased at the 12th hour, and increased again at the 24th hour of the treatment. According to the scanning electron microscopy results, the most affected groups by the application and duration were found to be the mineral water group at the 12th and 24th hours, and the milk group at the 24th hour. Fibers in all marinated squid muscles were observed to spring significantly more compared to the positive and negative control groups. The taste score was found to be significantly higher in the group treated with yeast for 3 h and it was evaluated by the panelists as the most delicious squid among all of the groups. As a result of the study, it was determined that the chemical, physical, and sensory properties of squid could be improved by marinating with yeast, milk, and mineral water for different durations.

Development and Quality Attributes of Paste Sausage Supplemented with Common Squid (Todarodes pacificus) Tailored for the Elderly

Modern consumers, especially the elderly, have a keen interest in healthy food choices. This study was conducted with the objective of developing squid paste sausages that are easily consumable by elderly individuals while also fulfilling their nutritional requirements. Response surface methodology (RSM) was employed to determine the ideal proportions for mixing raw common squid (RCS; 2.9–56.6%, A), isolated soy protein paste (ISPP; 0.3–37.8%, B), and surimi paste (SP; 25.5–64.7%, C) in order to create a common squid paste sausage prototype (CSPSP). The CSPSP underwent a comprehensive evaluation, encompassing its physicochemical, nutritional, and microbiological attributes, as well as consumer preferences, and was compared to Republic of Korea’s standards for senior-friendly foods. The optimal mixing ratios derived through RSM were as follows: RCSF, 38.7%; ISPP, 21.2%; and SP, 40.1%. Consequently, the hardness of CSPSP (CSPSP-A) prepared with these ratios was measured at 27.8 × 1000 N/m2, a remarkable 95.0% reduction compared to CSPSP-N. Moreover, the texture preference for CSPSP-A was rated at 8.5, signifying the highest level of preference. As a result, CSPSP-A earned a second-grade rating, indicating its suitability for safe consumption by elderly individuals with chewing disorders.

Economic evaluation of MSY-based fishery policy using input-output table: A case study of squid-related industries in Hakodate City, Japan

This study evaluates the regional economic impact of the MSY-based fishery policy on the squid industry, specifically in case of the Japanese flying squid (Todarodes pacificus) in Hakodate-city, Hokkaido Prefecture by coupling ecological-economic modeling. The results show that a 10-year MSY-based squid fishery in Hakodate would have an economic ripple effect of approximately −0.085 billion JPY in the case of normal recruitment, and 0.061 billion JPY in the case of low recruitment both in the present value with 4% annual discount rate. In the viewpoint of percentage, they are less than 0.3% of the economic ripple effects of the conventional fisheries, which indicates that the economic impact of MSY-based fisheries is not that significant. In addition, the decreased catch values during the first five years are so huge that the total present value of the MSY-based fishery is negative in the normal recruit scenario. This suggests that MSY-based fisheries are effective in dealing with the risks of low recruitment and requires long perspectives on policy implications. This study also recommends high-level bilateral dialogue between Japan and China on squid fishery management to decrease the uncertainty on the stock assessment.

No long-term variation of 240Pu/239Pu atom ratio in liver of Japanese common squid (Todarodes pacificus) collected from seven sea areas around Japan during 2003–2018

The 239+240Pu concentrations and 240Pu/239Pu atom ratios were determined to trace the temporal variability in concentration and atom ratio in liver of the Japanese common squid during 2003–2018. The differences in their concentrations and atom ratios and the dependency on the collection areas and migratory history were compared. The organ affinity of Pu in mantle, limb, liver, and internal organs except liver was also investigated. The average 239+240Pu concentrations were the highest in liver followed in order by internal organs except liver, limb, and mantle. The Pu accumulation in liver could be explained by a mechanism for foreign substance processing. A significant difference in the average 239+240Pu concentrations in liver was found among the sea areas for specimen collection during 2003–2018. In spite of a noticeable difference in the average 239+240Pu concentrations, the 240Pu/239Pu atom ratios showed no significant temporal variability around Japan; thus, they were continuously uniform during 2003–2018.

Diversity and Distribution of 18 Cephalopod Species, and Their Link with Some Environmental Factors in the NW Pacific

Some cephalopods are important fishery resources, with some major economic species living in pelagic waters, possessing short life history cycles, and responding strongly to environmental changes. The analysis of cephalopod community species composition, catch distribution, and their relationship with environmental factors in important marine areas can provide a basic reference for cephalopod biogeography and resource development and utilization. In this study, based on the cephalopod survey data in the spring of 2015 and summer of 2016 in the Pacific Ocean, we analyzed the cephalopod species composition, diversity index (the Margalef richness index, Shannon–Wiener diversity index, and Pielou uniformity index), main contributing species, and catch distribution in the two seasons of spring and summer in the Pacific Ocean. We also analyzed the relationship between cephalopod catch, each diversity index, and environmental factors in each season using the GAM model. The results show that 18 species of cephalopods were captured in the spring and summer, the Margalef richness index, Shannon–Wiener diversity index, and Pielou uniformity index in summer was higher than that in spring; the average catch biomass in spring was significantly higher than that in summer. The main contributing species in spring was Todarodes pacificus, while the main contributing species in summer was Ommastrephes bartramii. The interaction of the “longitude” and “latitude” has a great impact on cephalopod catch biomass in spring, and “sea surface temperature” has a great impact on cephalopod catch biomass in summer. The results of the study can provide a basic reference for the study of cephalopod diversity and resource development and utilization in the Pacific Ocean.

Study on the Geographic Variation and Trophic Variation of Todarodes pacificus in Different Areas Based on Stable Isotope Information from the Gladius.

The Japanese flying squid (Todarodes pacificus) is an important cephalopod in the northwest Pacific Ocean. In this study, the proostracum of the gladius of T. pacificus samples collected by Chinese squid fishing vessels in the East China Sea and the Sea of Japan in August and December 2018 were continuously cut, and stable isotope values of the cut fragments were used to analyze the migration path and feeding ecology of T. pacificus. The results showed that when the proostracum grew to 120 mm from the distal end, T. pacificus began to migrate. In the East China Sea, T. pacificus migrated to low latitudes and nearshore areas, and the trophic level of their food showed no large changes during migration. In the Sea of Japan, T. pacificus migrated to high latitudes and offshore areas, and the trophic level of their food showed a decreasing trend during migration. There was no significant difference in migration or feeding ecology between females and males, but the competitive capacity of the females may be stronger than that of the males. The results provided a scientific basis for the scientific management and development of T. pacificus resources.

Climate-Related Variations in Autumn Cohort of Japanese Common Squid Todarodes pacificus

Climate-Related Variations in Autumn Cohort of Japanese Common Squid Todarodes pacificus

Feeding Ecology of Common Squid Todarodes pacificus in the South Sea of Korea Determined through Stable Isotope and Stomach Content Analyses

The common squid Todarodes pacificus is a dominant species within epipelagic communities and an important commercial species in the South and East seas of Korea and in the East China Sea. In this study, to examine the dietary composition, trophic position, and ontogenetic dietary shifts of the common squid, we analyzed stomach contents and stable isotope values (δ13C and δ15N) in muscle tissue across different body sizes (mantle length, ML) and seasons (winter, spring, and summer 2021) in the South Sea of Korea. Regardless of the season, the diet of the common squid predominantly comprised Pisces (37.9–94.0%) and Cephalopoda (6.0–61.0%). However, in the smallest individuals (ML < 10 cm), the stomach contents in August primarily comprised Crustacea (95.5%), thereby indicating a seasonal difference in dietary composition and ontogenetic dietary shifts only during summer. Similarly, our isotope results revealed seasonal isotopic variation among sampling periods and significant positive correlations between ML and both δ13C and δ15N values during the summer. These results reveal a seasonal variability in major diet components among the common squid of different size classes and that their feeding strategies are probably adjusted in response to the temporal availability of prey. Collectively, the findings of this study enhance our understanding of the feeding ecology of T. pacificus and thereby provide valuable information that will contribute to the ecological fishery management of this commercially important species.

Genetic evidence for multiple mating and mixing of sperm from multiple males in the seminal receptacles of female Japanese flying squid (Todarodes pacificus)

ABSTRACT The genetic diversity of sperm and spermatangia stored by mated Japanese flying squid (Todarodes pacificus) was examined to better understand how this ommastrephid squid mates and stores sperm. Analyses were conducted using spermatangia implanted in the lips of immature squid collected in Tsugaru Strait, northern Japan, in July–August 2019, spermatangia implanted in the lips of mature squid collected in the East China Sea in April 2019, and sperm stored in the seminal receptacles of squid collected off Tosashimizu, Kochi Prefecture, Japan, in February 2019. DNA was extracted, microsatellite loci were amplified using five PCR primers, and allele peaks were analysed. Analysis of the spermatangia confirmed that females in the field mate with multiple males, suggesting that males transfer from 1 to at least 14 spermatangia in each mating. Analysis of the seminal receptacles showed that sperm from multiple males are mixed within individual sperm chambers. Spermatangia were also found implanted in the lips of males, providing evidence of same-sex sexual behaviour. To date, studies of cephalopod mating systems have focused on coastal species, and the results of this study add to our growing knowledge of more oceanic species.

Long-term changes in body size of Japanese flying squid <i>Todarodes pacificus</i> caught in the offshore area of the Sea of Japan

Long-term changes in body size of Japanese flying squid <i>Todarodes pacificus</i> caught in the offshore area of the Sea of Japan

Kinetic Modeling for Predicting the Quality of Squid (<i>Todarodes pacificus</i>) during Storage and Distribution

Kinetic Modeling for Predicting the Quality of Squid (<i>Todarodes pacificus</i>) during Storage and Distribution

Biomonitoring of Pu isotopes in liver of North Pacific giant octopus (Enteroctopus dofleini) collected off the Rokkasho Nuclear Fuel Reprocessing Plant, western North Pacific margin

Concentrations of 239+240Pu and 240Pu/239Pu atom ratios were determined in liver samples of North Pacific giant octopus (Enteroctopus dofleini) collected off the Rokkasho Nuclear Fuel Reprocessing Plant (RNFRP) to understand the bioaccumulation of Pu in the octopus liver, to provide Pu data before full commercial operation of the reprocessing plant, and to identify the sources of Pu isotopes in the studied liver samples. Mean 239+240Pu concentration was 6.3 ± 3.1 mBq/kg-wet, which was within the previously reported concentration ranges in liver of the Japanese common squid and in hepatopancreas of red queen and snow crabs. The 240Pu/239Pu atom ratios ranged from 0.223 to 0.252 with a mean ratio of 0.234 ± 0.009, which was noticeably greater than the mean global fallout ratio of ~0.18. These ratios reflected a mixture of global fallout Pu from atmospheric nuclear weapons testing and close-in fallout Pu from the Pacific Proving Grounds (PPG). The relative percentage of the PPG close-in fallout Pu to global fallout was calculated to be 39.6 ± 6.7%. The liver of the NPG octopus is an excellent bioindicator for biomonitoring of Pu pollution. Data on 239+240Pu concentrations and 240Pu/239Pu atom ratios in liver of the NPG octopus collected in the vicinity of the RNFRP will provide powerful keys for continuous biomonitoring of Pu pollution and for distinguishing the potential sources of Pu after the plant begins full commercial operation.

Structural and Phylogenetic Profiles of Muscle Actins from Cephalopods

Structural properties of cephalopod muscle actins have not been characterized in detail to date. Sequences of these actins have been determined by cDNA cloning from the arm muscles of four cephalopod species, namely, Japanese common squid Todarodes pacificus, spear squid Loligo bleekeri, common cuttlefish Sepia esculenta, and common octopus Octopus vulgaris. The sequence identities of the deduced amino acid sequences among the cephalopod actins were around 98%, and the substitutions were mostly limited to Subdomains 1 and 3. Phylogenetic analyses revealed that cephalopod actins formed one cluster and were distinguishable from the bivalve counterparts. The modeled tertiary structure of squid actin was very similar to that of rabbit counterpart, but the structures of Subdomains 1 and 3 were slightly different.