Abstract:The cephalopods are one of the most potential fishing species in the world and have become an important component of the world's marine fishing industry. The world cephalopod fisheries and their composition were analysed using the grey association method based on the world cephalopod production statistics from 1970 to 2016. According to the development status of China's pelagic squid fishery, the problems are pointed out and the development countermeasures are put forward. The analysis found that the world's cephalopod fishing production in the period from 1970 to 2016 generally showed a relatively stable growth trend, with an annual growth rate of 3.68%, which is much higher than the growth rate of world marine fishing production in the same period, and reached its highest level ever in 2014. Between 2010 and 2016, the proportion of cephalopods in world fishing production stabilized between 4.5% and 6.0%. The composition and proportion of the production for different families have varied from one generation to another, and the production of main countries and areas has changed greatly. In the 2010s, the proportion of each family was Ommastrephidae (58.41%), Loliginidae (11.98%), Octopodidae (8.92%), and Sepiidae (8.40%). Asia has played the important role in the cephalopod fishery in the world for more than 40 years. Japanese cephalopod production fell from 1st in the 1970s to 5th in the 1990s and 2010s, and China rose from 5th in the 1970s to 1st in the 2000s and 2010s. The lack of knowing, developing and controlling abilities over pelagic squid resources is a major constraint on the sustainable development of pelagic squid fisheries in China. Therefore, a global information service system should be developed on the fishing conditions of pelagic squid fisheries, a system for the standardization of fishing gear and equipment with independent property rights, the catch quality control technologies and traceability systems should be developed, information-based construction of ocean-going fisheries should be carried out based on Internet of Things projects, and the cephalopod fishery resources assessment system should be established.

Abstract:The study aimed to reveal the trends and research hot spots on oceanic squid jigging fishery in the world, and promote the sustainable development of China's oceanic squid jigging fishery.We used the method of bibliometric analysis to review the document related to the study on oceanic squid jigging fishery and indexed ISI Web of Science Core Collection database. We first created descriptive statistics of the number of articles published annually and the journal frequency distribution. Then, the methods of author, institution cooperation network and keyword based knowledge mapping and burst analysis were used to explore the hot spots of world oceanic squid jigging fishery studies and the recent frontiers. Descriptive statistics suggested that the number of studies on world oceanic squid jigging fishery has increased sharply in the past decades and the scientific research influence and international attention of the document are very high.Authors and institutions have formed frequent and stable cooperative relations. Authors' cooperation has formed two major groups, as the core with Chen Xinjun, Chen Yong et.al.and Rodhouse P G et.al. Institutional cooperation has established extensive cooperative relations as the core with Shanghai Ocean University and the British Antarctic Survey.Marine freshwater biology, fisheries, oceanography and ecology are the dominant disciplines in world oceanic squid jigging fishery. Results of the burst analysis of the most recent document hot spots showed that the current research in world oceanic squid jigging fishery has four study frontiers:(1) carry out basic Biology and Ecology research in important oceanic economic squid species; (2) study the resource assessment of oceanic squid and its response mechanism to global climate and environmental changes; (3) research on fishery habitat based on marine remote sensing information and interdisciplinary integration; (4) study on integrated management of ocean squid fishery resources based on ecosystem.

Abstract:Oceanic squid is an important marine living resource and has great potential for exploitation. Chinese oceanic squid fishery began in 1989. After nearly 30 years of development, Chinese oceanic squid fishery has become an important component of distant-water fishery and has become the largest in the world. In the course of development in the past 30 years, through the cooperation of fisheries industry, education and research units, the oceanic squid resources have been continuously investigated by using fishing vessles in the three oceans, and some new squid resources have been continuously developed and utilized commercialy. Therefore, based on the data collected by Chinese squid fishing vessel from 2003 to 2017, the paper analyzes the basic biology, resource distribution of squid and its relationship with water temperature, and summarizes the development of squid jigging fishery in China. The countermeasures and suggestions for sustainable development of oceanic squid resources in the world are put forward. The study indicated that through a productive survey of seven oceanic squid resources in the three oceans, including the Indian Ocean, the Pacific Ocean and the Atlantic Ocean, four new squid fishing grounds have been discovered for the first time in the world, and more than 10 million square kilometers of new fishing areas have been added. It is estimated that the resources of the new oceanic squid are more than 5 million tons. However, due to the limited time available for investigation and the limited knowledge of the newly developed squid life history process, it is recommended that a systematic and scientific international cooperative survey, including age and growth, population structure and life history processes, and migratory distribution based on hard tissue of oceanic squid should be carried out. The research on high-precision fisheries forecasting, and assessment and management strategy of oceanic squid resources should be also developed, which will help to realize rational exploitation and utilization of oceanic squid resources in the world.

Abstract:Squid belongs to Cephalopoda, which is abundant in the East China Sea. The processing and drug utilization of marine cephalopods have a long history. In the past 30 years, squid processing industry in China has developed rapidly and has become one of the main components of aquatic products processing industry in China. With the progress of biotechnology and the continuous development and utilization of marine resources, the processing research of squid has gradually deepened. The production and types of processed products such as frozen squid slices, seasoned squid shreds, squid rice and squid seasoning have been constantly enriched. The comprehensive processing of by-products and the extraction, utilization and product development of effective functional components such as anti-tumor, anti-oxidation, immune function regulation, blood lipid and blood pressure lowering and other biological active substances, are also diverse. Squid has become a hot spot for the development and utilization of functional foods and new marine drugs. The current status of squid processing technology is introduced, and the research progress is briefly described from the comprehensive utilization of viscera, skin, ink, eye and cartilage, etc., aiming to provide a basis for the further development and utilization of squid resources in the future.

Abstract:Cephalopod beak has a stable structure, and it is a good material for species identification. According to the six species of cephalopod samples (Loligo chinensis,Uroteuthis duvauceli,Sepia pharaonic,Sepia kobiensis,Octopus ocellatus and Octopus variabilis) caught from East China Sea and Yellow Sea, the beak morphometrics are measured, discriminant analysis is made at family level, the results are compared between non standardization data and standardization data. The results showed that non standardization beak morphometrics of Loligo chinensis and Sepia pharaonic is bigger than Uroteuthis duvauceli and Sepia kobiensis, respectively,but the results are reversed after standardization data. Beak morphometrics of Octopus ocellatus is biggger than Octopus variabilis for both non standardization data and standardization data. Ten non standardization beak morphometrics were selected for the final discriminant analysis, and upper hood length (UHL), lower crest length(LCL), lower wing length (LWL) contribute most to the morphological variation,total successful discriminant rate is 92.8% for the three families; seven standardization beak morphometrics were selected for the final discriminant analysis,and upper hood length/mantle length (UHL/ML), lower crest length/mantle length (LCL/ML), lower wing length/mantle length (LWL/ML) contribute most to the morphological variation, and total successful discriminant rate is 98.1% for the three families. In conclusion, it can effectively improve the discriminant rate after data standardization for beak morphometrics.

Abstract:The beak was one of the most important hard tissues of cephalopods which was widely used in the study of cephalopod fisheries biology and fishery ecology research. According to the measurement of the morphological parameters of the beak from 818 Sthenoteuthis oualaniensis samples collected by Chinese falling-net fishery during January to March of 2017 and 2018 in the Xisha Islands waters of the South China Sea, the morphological growth characteristic of the beak of S.oualaniensis was studied. The principal component analysis showed that the upper hood length (UHL), the upper crest length (UCL), the upper wing length (UWL), the upper lateral wall length (ULWL), the lower hood length (LHL), the lower crest length (LCL),the lower wing length (LWL) and the lower lateral wall length (LLWL) could be used as themorphological characteristic parameters to study the morphological changes of the beak. The analysis of covariance (ANCOVA) showed that there were significant differences in the relationships between UHL, LWL versus mantel length (ML) between males and females, but no significant difference was found in other characteristic parameters. The relationships between beak morphological variables and body weight (BW) differed significantly between males and females in all of the morphological characteristic parameters. The relationships between LLWL,UHLof males and ML were optimally described by the linear growth models, and exponential functions were optimal for the other parameters. The logarithmic functions were optimal for the relationship between the ULWL, LHL, LCL, LWL, LLWL and BW for females, however exponential equations were optimal for the UCL,UWL, and linear functions were optimal for the other parameters for males.

Abstract:Based on 113 Dosidicus gigas specimens collected from the sea of Peru, the microstructure of eye lens is analyzed and the periodicity of the formation of growth increments is validated. Results shows that eye lens consists of two halves:the front and back. The plane with the largest diameter is the equatorial plane, records all growth increments of lens. Eye lens is composed of hood and crest, in which light-dark alternated concentric growth increments are distinct. From the core to the edge of the eye lens, the spacing between adjacent growth increments gradually decreased and there is no obvious transition zone.The average diameter of the eye lens is 7 mm, and the average daily growth of 7 increments. Through paired sample t test, it was found that there was a significant difference between the increments of eye lens and statolith-determined age (P<0.05). The lens growth increments A of the sample showed an exponential relationship with the lens diameter D, (D=6.88e^{0.000 09A},n=113,R²=0.578 1) and also had an exponential relationship with the mantle length ML (L_ML=216.25e^{0.000 2A}, n=113, R²=0.463 2). Although the results of the study negate the possibility of a daily periodical pattern of lens increments of the D.gigas, it can be regarded as individual growth analysis indicators, at the same time and it provides important basic literature for Chinese scholars to study the age growth of cephalopods.

Abstract:The beaks of cephalopods have stable chemical compositions and firm physical structures. Recently, with the increasing use of stable isotope analysis in ecology, it becomes a powerful tool and complement of traditional methods for investigating the trophic ecology and migration patterns of invertebrates. This research was based on 18 Uroteuthis duvauceli specimens, 18 Sepiella maindronis specimens, 20 Octopus ocellatus specimens and 15 Uroteuthis edulis specimens, which were collected in August 2013 from the East China Sea. The beaks of these four kinds of offshore species were studied by determining their carbon stable isotope(¹³C/¹²C,δ¹³C)and nitrogen stable isotope(¹⁵N/¹⁴N,δ¹⁵N).In order to find the differences of these species' habitats and the foraging behaviors, the δ¹³C and δ¹⁵N values were analyzed to see whether there was a correlation with their mantle lengths. The study aimed to explain the habitats of different cephalopods and find their position in the ecological system, not only providing materials for further development and management, but also giving a basis for the better use of these species. The results showed that the average values of mantle length for four species:U.duvauceli > U.edulis > S.maindroni > O.ocellatus(122.72mm > 67.93 mm > 67.93 mm > 35.3 mm). The average values of body weight for four species:U.duvauceli > S.maindroni > O.ocellatus > U.edulis > (70.39 g > 50.67 g > 47.35 g > 19.93 g). S.maindroni have the maximum δ¹⁵N value (10.81‰±0.38‰),the minimum δ¹³C value (-14.98‰±0.55‰),the minimum C/N(3.08±0.03)and U.edulishave the minimum δ¹⁵N value (8.21‰±0.30‰), the maximum δ¹³C value(-13.00‰±0.54‰), the maximum C/N(3.57±0.06), U.duvauceli and U.edulislive in the shallower water area than the S.maindroni and O.ocellatus. And the δ¹³C and δ¹⁵N values between U.duvauceli and O.ocellatus were very similar (ANOVA, P>0.05), their ecological niches were much overlapped, they may have the similar trophic level. The δ¹³C and δ¹⁵N values of other kinds of species had significant differences (ANOVA, P<0.05). In addition, the δ¹³C values of U.duvauceli and the mantle length (ML) showed a significant liner relationship (δ¹³C=0.023 6×L_ML- 17.429,P<0.05), δ¹⁵N values also showed a significant liner relationship with the mantle length (ML) (δ¹⁵N=0.017 6×L_ML+ 6.873,P<0.05), but there was no significant correlation between carbon and nitrogen stable isotopes with the mantle length in S.maindroni, O.ocellatus and U.edulis (P>0.05).It showed that there was no significant connection between feeding habit and mantle length.

Abstract:Trophic position(TP) of organisms is fundamental for assessing and describing food web structure. Compound-specific nitrogen isotope analysis of amino acids (AA-CSIA) may be a promising tool to estimate more precisely and accurately the TP of marine organisms than the traditional methods, specifically the highly migratory pelagic species. The jumbo squid (Dosidicus gigas) is a pelagic cephalopod endemic to the eastern Pacific Ocean. In this study, AA nitrogen isotopic values (δ¹⁵N)of squid muscle tissues were identified and compared among three sampling locations, and the TPs were also evaluated. Results showed significant differences in AA δ¹⁵N values among squid muscle tissues from different areas. The threonine, however, had lowest δ¹⁵N values, which might be due to its special nitrogen isotope fractionation mechanisms.The spatial heterogeneity of AA δ¹⁵N values was mainly influenced by proline, glutamic acid,aspartic acid, serine and lysine, indicating the variety of dietary habits and isotopic baseline values. In addition, utilizing the isotopic differences between three and more AAs to estimate TP might be more accurate than only using glutamic acid and phenylalanine. The present study provided a beneficial reference for further research on foraging ecology in pelagic cephalopod.

Abstract:Argentinean short-fin squid, Illex argentinus, is an important Cephalopod species, characterized by fast growth, short lifespan and semelparous reproduction. It has been assumed that the stock biomass is closely related to the nutrients acquisition, accumulation and subsequent allocation to reproduction during the sexual maturation. In order to understand the fatty acid composition and its changes during sexual maturation in female Illex argentinus, the fatty acid profiles and their relative content in multiple tissues, namely mantle tissue, digestive gland and ovary, were investigated by the methods of chloroform-methanol and gas chromatography. The results indicated that the polyunsaturated fatty acids (PUFA) were the most abundant fatty acid class for the tissues investigated, followed by saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). A total of 28 fatty acid profiles were detected in mantle tissue, while digestive gland and ovary were had 21 fatty acid profiless and 17 fatty acid profiles, respectively. It was found that most of SFA content was presented as C16:0, MUFA content as C18:1n9c and C20:1, and PUFA content as docosahexaenoic acid (DHA; 22:6n3) and eicosapentaenoic acid (EPA; 20:5n3). During the sexual maturation, both SFA content and MUFA content in mantle tissue attained the highest level at mature stage, and then decreased significantly at spawning stage, probably indicating these fatty acids were mobilized to fuel reproduction. PUFA content in digestive gland was significantly lower than that in mantle tissue or ovary, even though it maintained a relatively stable status throughout sexual maturation. The ovary continuously accumulated fatty acid content, but showed a significant decrease in MUFA content and PUFA content during the spawning period, possibly suggesting that these fatty acids were increasingly allocated to oogenesis. These evidence indicated that the fatty acid profiles in Illex argentinus showed tissue-specific characteristics, while the major fatty acid profiles were consistent in mantle tissue, digestive gland and ovary. In the mantle tissue, both SFA and MUFA were possibly mobilized to fuel reproductive growth during sexual maturation. In the digestive gland, the PUFA content might be continuously transferred to mantle and ovary with maturation. Regarding fatty acids in the ovary, the content might be continuously accumulated and subsequently used to support oogenesis during the sexual maturation.

Abstract:According to the acoustic navigation survey data of four voyages in the Nansha sea area in 2013, combined with remote sensing, sea surface temperature (SST), sea surface height (SSH), sea surface salinity (SSS) and marine environmental data such as chlorophyll-a concentration (chl.a), using the generalized additive models (GAM), a relationship model between fishery biomass and marine environmental factors was established. The research shows that:There are obvious seasonal differences in the distribution of squid fishing grounds in the Nansha Sea area, in spring the fishing ground is mainly concentrated in the southwestern part of Nansha and the eastern part of Vietnam, in summer and autumn, the fishing ground is mainly distributed in the southern part of Nansha, and in winter the fishing ground is mainly distributed in the south and south of Nansha; SSH in various environmental factors and SSS have a significant impact on fishery biomass, SST and chl.a are not significant; The main factors affecting the biomass of fishery are SSH, SSS, longitude (LON) and latitude (LAT), and the optimal relationship model between fishery biomass and impact factor is established based on Akaike Information Criterion (AIC); The total deviation interpretation rate of the model is 54.7%; Among the four factors in the optimal model, the latitude has the greatest impact on the model; The formation of the South China Sea squid fishing ground is closely related to the influence of ocean currents.

Abstract:The fishery data of neon flying squid (Ommastrephe bartramii), vertical profile sea water temperature, and thermocline characteristic parameters via Argo temperature profile buoy data from 2007 to 2016 were analyzed, to examine the seasonal variations between the central fishing ground and vertical water temperature structure in the northwestern Pacific Ocean. The yield season of neon flying squid was from May to November, with the peak months in August and September, while the fishing areas contered in the region 150°E-160°E and 39°N-45°N, and CPUE exceeded 2 t/(d·V). The relatively low CPUE appeared at the months from May to July, and October to November. The fishing grounds were relatively dispersed before August and after September, with relatively low CPUE. The obvious changes of seasonal temperature appeared at the thermocline of upper and lower boundaries, and 0-50 m and 0-100 m water depth. The difference value of water layers temperature gradually increases from July, with 5.17℃ at ΔT_{0-50 m} and 7.68℃ at ΔT_{0-100 m}. The highest difference value of ΔT_{0-50 m} appeared in September, with a value of 9.89℃, and ΔT_{0-100 m} appeared in September, with a value of 12.64℃ respectively. ΔT_{0-50 m} and ΔT_{0-100 m} began to decline gradually from October to November. In the western region, west of 160°E traditional fishery waters at 20 to 50 m, upper and lower bounds of the thermocline depth corresponding to the water temperature range of 4 to 17℃. At same time, water temperature on the lower thermocline ranged from 3 to 11℃, at depth between 150 and 230 m. The result showed that the higher ΔT_{0-50 m} and ΔT_{0-100 m} were, the higher CPUE was, indicating that neon flying squid resources offered higher density and better catches when the temperature of thermocline decreased greatly. The research on the characteristics of vertical water temperature structure of neon flying squid fishery provides a reference for the prediction of fishery situation and fishery production in the northwestern Pacific Ocean.

Abstract:According to the trawl survey data along north coast of Zhejiang Province during spring and summer of 2014 to 2016, the spatial-temporal factors (year, month, latitude and longitude) and environmental factors (sea bottom temperature, SBT; sea bottom salinity, SBS; depth; dissolved oxygen, DO) were selected to analyze the spatial-temporal distribution of Octopus minor, as well as its relative importance using boosted regression tree (BRT). The results showed that the average catch in 2014 is higher than that of 2015 and 2016, and the catch in April is also higher than other months in the same year; the main catch distributed ranged from 122.75°E to 123.25°E,30°N to 30.5°N;the gravity of fishing ground in 2015 moved a little northward compared with the other two years, the gravity of fishing ground also moved a little northward during April to June; the learning rate (lr) 0.001 and tree complexity (tc) 4 were selected to establish the model between environmental factors and catch, and dissolved oxygen (DO) was the most important factor, accounting for 45.5%, then year and salinity, accounting for higher than 10%, then successively, depth (10.7%), SBT (7.3%), latitude (4.7%), month (4.7%) and longitude (2.3%). Environmental factor is more important than spatial-temporal factor to the catch of Octopus minor. Future studies should pay more attention to the dissolved oxygen as it is a critical factor that directly influences the marine organism.

Abstract:As a short life cycle species, the resources of neon flying squid in northwestern Pacific Ocean fluctuate greatly during the years, mainly because the population is extremely sensitive to mesoscale climate change and changes of environmental conditions of its spawning ground. Therefore, it is particularly important to study the environmental conditions of the spawning ground of neon flying squid and obtain the most suitable temporal and spatial environmental factors. In a stable mesoscale climate model, based on the scientific conclusion that the ratio of the optimal temperature range of the squid spawning field to its spawning range (P_S) is positively correlated with its resource replenishment, this study intends to conduct a regression analysis of the CPUE of the neon flying squid in 1996-2007 and the Ps of 6 468 hypothetical spawning grounds in each month of January-April, screening out the spawning season, spawning grounds and the optimum SST range of spawning grounds which were statistically significantly correlated with CPUE and P_S. Studies indicate:during 1996-2007, the spawning season is from Jan. to Mar.; The optimal spawning range is 136.5°E-167°E, 20.5°N-27.5°N; The optimum SST range for spawning ground is 22.5-26℃. The results of this study contribute to the understanding of the life cycle process of squid and the prediction of its resource supplement, which provides a basis for the sustainable development and scientific management of squid resources.

Abstract:The neon flying squid Ommastrephes bartramii from is a migratory ommastrephidae squid species with ecological importance and economic values. At present, O. bartramii is mainly targeted by the squid-jigging fishing vessels from Japan, ROK and China and so on. O. bartramii has only 1-year life span, therefore, its habitat suitability is largely affected by climate variability and environmental conditions. In this study, an integrated habitat suitability index (HSI) model was developed based on the fishing effort and the arithmetic mean method by using the fisheries data from September to November during 2006-2015 obtained from the data centers of Chinese squid-jigging fishery combined with two key environmental variables including sea surface temperature (SST) and photosynthetically active radiation (PAR). This study further evaluated and compared the impacts of very strong El Niño and strong La Niña on habitat suitability of O. bartramii. Results showed that habitat modeling method based on SST and PAR could effectively predict the habitat hot spots of O. bartramii in the Norwest Pacific Ocean. It was clearly found that the suitable ranges of SST and PAR varied monthly, and the ranges decreased from September to November. The catch, fishing effort and catch per unit effort (CPUE)tended to linearly increase with the habitat suitability index. Comparing the 2007 year with strong La Niña and the 2015 year with very strong El Niño, it showed that the CPUE and habitat suitability in 2007 were higher than those in 2015. The difference might be attributed to the high enlargement of suitable area of SST and PAR in 2007due to the strong La Niña, while the very strong El Niño in 2015 led to the sharp decrease of suitable area for both SST and PAR. All of these resulted in the low CPUE.

Abstract:To fulfill the needs of fishing ground forecasting system of domestic fishery companies, a fishing ground forecasting system is developed based on near real-time remote sensing data. The system has two modules, the land data service module and the fishing ground forecasting software module. The land service module is responsible for collecting the global near real-time marine environment data and providing the environmental data downloading service. The fishing ground forecasting software module can download the marine environment data from the land server and use the data to forecast the fishing ground using the habitat suitability index model. The system uses the International Maritime Satellite broadband services as data transmission channel. Former application tests of deep-sea fishing vessels indicated that the system can download the environmental data stably and calculate the potential fishing ground, which is important auxiliary information for fishing decision and can be used as a reference for fishing location selection.

Abstract:Stock assessment and management strategy evaluation of Illex argentinus was made based on metapopulation. Single population is the basic hypothesis for the present fishery stock assessment. However, resources are usually composed of several populations and communicate with each other, which can form metapopulation. In this paper, the abundance of I. argentinus is assessed based on Bayesian statistical Schaefer model with single population and metapopulation. The results showed that year capture data and resource abundance index could provide sufficient information for Bayesian stock assessment model. The estimated maximum sustainable yield is similar to prediction value of model parameters for both single population and metapopulation. Catch mortality is lower than F_lim for single population, while catch mortality is higher than F_lim for south metapopulation. Abundance recovers to good condition with decreased catch mortality. Decision analysis showed that the abundance could keep at sustainable level under single population and metapopulation with yield rate at 0.3. Yield rate should be set between 0.2 and 0.3 for conservative strategy, where the sustainable catch is around 0.8 million tons.