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We examined specimens from the winter–spring cohort of the neon flying squid Ommastrephes bartramii caught off the coast of northeastern Japan in early summer and the following winter for mantle length, sex, maturity, and age to determine their hatching dates as well as their growth and migration patterns. Squid specimens were collected with a research driftnet in July 2018 in the northwestern Pacific and by squid jigging off the coast of northeastern Japan in November 2018 and January 2019. The ages of 300 specimens were estimated from statolith increment counts and used to back-calculate hatching dates. Hatching dates ranged from September 2017 to July 2018. The peak hatching dates varied with the survey season, even for the same winter–spring cohort. Squid caught in July 2018 hatched mainly from February to April, while those caught in November 2018 hatched mostly during April and May and those caught in January 2019 hatched principally during May and June. This pattern indicates that squid migrate among fishing grounds and that stocks are gradually replaced by late-hatching squid.

Dosidicus gigas is an economically important species distributed in the Eastern Pacific Ocean. Unraveling the genetic population structure of this species is crucial to ensure its fishery sustainability and management. Mitochondrial DNA sequences and nuclear neutral loci are useful to understand how historical and contemporary factors drive the genetic population structure of species. However, most studies investigating genetic structuring of D. gigas from its northern and southern populations rely on patterns identified using mitochondrial genes. The use of both types of DNA markers is especially relevant for marine species with high dispersal capabilities such as D. gigas. Here, we describe the genetic structure of D. gigas using partial sequences of the mitochondrial gene NADH dehydrogenase subunit 2 and nuclear microsatellite loci in populations of the northern hemisphere from the Costa Rica Thermal Dome and off Ecuador; and, of the southern hemisphere from the South Equatorial Current and off Peru. Statistical parsimony network and Bayesian analyses from mitochondrial sequences revealed three historical maternal lineages in both hemispheres, with high levels of genetic differentiation and signatures of population expansion during the late Pleistocene. Use of Discriminant Analysis of Principal Component (DAPC) with microsatellite loci of mature and immature individuals showed the presence of at least two contemporary genetic stocks homogeneously co-distributed in both northern and southern hemispheres, which can be explained by the biological characteristics of D. gigas and the variable oceanographic conditions of the Eastern Pacific Ocean. Overall, our findings indicate that cooperation between countries with intensive fishing will benefit the sustainability of D. gigas.

Pacific saury, Cololabis saira, are widely distributed in the central Pacific Ocean during the pre-fishing season (June and July) and migrate westward to fishing grounds off the coast of Japan from August to December. This study clarified the relationship between pre-fishing distribution and immigration to the fishing grounds (i.e., the relationships among distribution during the pre-fishing season, immigration rate to fishing grounds, immigration date, and westward velocity) in age-1 (1 year old) Pacific saury using the radius of otolith annual rings (ROAs) as a natural tag to improve fishing predictions based on stock assessments via pre-fishing surveys. The ROAs of Pacific saury collected from 2003 to 2014 were measured to quantify their geographical variation during the pre-fishing season and temporal changes during the fishing season. Pacific saury with larger ROAs were distributed in the western area during the pre-fishing season and immigrated to the fishing grounds early during the fishing season. Differences in the relative proportions of each ROA size class between the pre-fishing and fishing seasons suggest that Japanese fishing fleets non-selectively caught fish immigrating from a broad area. Dates of immigration to the fishing ground were correlated with the longitude at which Pacific saury were distributed during the pre-fishing season ( r2 = 0.48). Furthermore, westward migration velocities estimated for this period (range: 0.087–0.410° longitude/d) were highly correlated with the longitude of their distribution during the pre-fishing season ( r2 = 0.80). This result suggests that the mean immigration date of age-1 Pacific saury found in each area during the pre-fishing season could be predicted based on their estimated westward velocities. In conclusion, our Pacific saury migration results provide important information to improve the management and sustainability of this important fishery stock.

Habitat suitability index (HSI) models were applied to identify the potential habitat distribution of the neon flying squid (Ommastrephes bartramii) off the eastern coast of Japan during winter. We used an ocean reanalysis product, a satellite-derived dataset, and commercial fisheries data during 2003–2008 to develop the HSI models, and illustrated the characteristics of the ocean environments at the fishing ground of the neon flying squid, focusing on a typical fishing ground formation event in 2006. The estimated HSI fields of the neon flying squid using three-dimensional (3D) ocean environmental parameters showed a clear relationship between the squid habitat and the edge of a warm core ring south of the Oyashio water; this is considered a key characteristic of fishing ground formation, as noted in Sugimoto and Tameishi (Deep-Sea Research, 39, 1992 and S183). This result suggests that mixing of the warm and nutrient-poor Kuroshio water and the cold and nutrient-rich Oyashio water at the edge of the ring could provide favorable conditions for the foraging of the neon flying squid. The warm water condition in the subsurface layers could be a further advantage to the formation of a stable fishing ground for the neon flying squid. Comparison of the Akaike Information Criteria among a satellite-data-based model, a reanalysis-based model using the same parameters as the satellite-based model, and a reanalysis-based model using 3D ocean environmental parameters, showed an apparent improvement in the performance of the reanalysis-based model using the 3D parameters, reproducing realistic features of the squid fishing ground during the winter of 2006.

Understanding the community structure of oceanic higher trophic level (HTL) organisms (e.g., sharks, tunas, salmons, and squids) is fundamental to management of marine resources in a way that ensures their sustainable use and maintains marine ecosystem functionality and biodiversity. We analyzed the spatial structure of HTL assemblages in the western North Pacific Ocean using driftnet survey data collected at latitudes of 35–46 °N along transect lines at 144 °E, 155 °E, and 175.5 °E longitude in July and August 2011. We proposed a new dissimilarity metric segmentation procedure (Dissimilarity Segmentation) based on the differences of mean Bray-Curtis dissimilarity indices between two individual driftnet hauls within the same subarea or among different subareas. Dissimilarity Segmentation allowed us to divide the western North Pacific Ocean into three subareas: a northern subarea (>41 °N including 41 °N on the 175.5 °E transect), a transition subarea (37–41 °N), and a southern subarea (

The pronghorn spiny lobster Panulirus penicillatus is known to have the widest distribution among palinurid lobster species, occurring in tropical and sub-tropical areas of the Indo-Pacific Ocean. In the Pacific Ocean, mitochondrial DNA analyses have revealed that the western–central and eastern populations are genetically isolated. We performed morphological investigations on mid- to late-stage phyllosoma larvae collected in these two areas. The larvae of the western–central population had a significantly narrower cephalic shield, shorter abdomen, and longer eyestalk than those of the eastern population. Additionally, for larvae larger than about 25-mm body length, the widest position of the cephalic shield in the western–central population was located closer to the middle of the median line of the cephalic shield than that in the eastern population. The ratio of width to length of cephalic shield and the ratio of cephalic shield width to thorax width are key traits for distinguishing between the larvae of the two populations.

We investigated the impacts of extensive anthropogenic (high seas driftnet squid fishery) and natural (late 1990s major climate regime shift) events on dominant epipelagic fish, squid, and shark in the central North Pacific Transition Region based on a driftnet survey covering the years 1979–2006. Fishing was conducted by Japan, Korea and Taiwan to target neon flying squid in the period 1979–1992, resulting in a decline in stocks of the target species and non-target species (Pacific pomfret and juvenile blue shark), which were by-catch of this fishery. The catch was found to be at the maximum sustainable yield (MSY) level for neon flying squid, the underfished level for juvenile blue shark, but the overfished level for Pacific pomfret. The MSY of Pacific pomfret indicated that this species is more susceptible to exploitation than previously considered. In response to the late 1990s regime shift, neon flying squid and Pacific saury showed low stock levels in 1999–2002 and 1998–2002, respectively, as a result of reduced productivity in their nursery grounds (the Subtropical Frontal Zone and Kuroshio Extension Bifurcation Region, respectively). On the other hand, Pacific pomfret showed no decreasing trend in stock during the low- and intermediate-productivity regimes because of the high productivity of their main spawning/nursery ground (Transition Zone Chlorophyll Front), which was independent of the regime shifts. Thus, squid and saury appear to be more susceptible to the regime shift than pomfret. We discuss the implications for stock management of the species-specific responses to the fishery and the regime shift.

Drifting gill-nets were for a long time the main research gear for investigating the distribution of Pacific saury Cololabis saira. However, it has proven to be difficult to estimate the absolute abundance of saury using drifting gill-nets due to a lack of knowledge on the survey areas swept by these gill-nets. A mid-water trawl stock abundance estimation has the advantage of being able to estimate the absolute stock abundance before the commercial fishing season begins, whereas the conventional stock abundance estimation based on catch per unit efforts of commercial fisheries must be done after the commercial fishing season has ended. To confirm the practicality of a mid-water trawl to estimate the stock abundance of saury, we conducted a comparative survey in the northwestern Pacific Ocean using both a mid-water trawl and drifting gill-nets. We found that the geographic distribution pattern of catch per unit effort for both the mid-water trawl and driftnets was similar. Using the area-swept method and data on the fishing efficiency of the mid-water trawl obtained in a previous study, we were able to estimate the stock abundance plus confidence limits within the research areas. Our results suggest that the size composition of saury sampled by the mid-water trawl can be considered to approximate the actual size composition of saury.

Jumbo squid, Dosidicus gigas , is commercially important species in the Eastern Pacific Ocean, principally in the Northern Humboldt Current System where is notably abundant. In this area, jumbo squid display difference in density at geographical level, in size of mature individuals and inter-annual demographic fluctuation. Thereby, a population genetics study of jumbo squid in this location is needed especially for fisheries management. This study evaluated the population genetic of this squid ( n = 120) based on novel microsatellite loci and 675 bp of the mtDNA ND2 divided into two groups according to the Geographical density and Size at maturity. Our results at nuclear loci showed an overall low genetic diversity and no signatures of genetic differentiation of any group. At mtDNA loci level, low but significant genetic differentiation were detected between Small ( n = 33) and Large ( n = 39) populations. The low genetic diversity is more likely explained by a historical demographic expansion whereas the contradictory results of population structure may be due to the low number of microsatellite loci in HWE, different maternal history of this species or the different influence of genetic drift on mitochondrial and nuclear genes. Furthermore, demographic history analysis suggested that jumbo squid population went through a period of pure demographic expansion over the last 50,000 years ago. This study provides results of combined nuclear and mtDNA molecular markers that was never reported before and may represent a valuable information for the monitoring of the population genetic of this species.

The present study seeks to incorporate a highly variable DNA barcode marker, additional to the standard regions of the cytochrome oxidase I gene and the 3′ end of the 16S large ribosomal subunit (16S rRNA), for a more effective species-level identification among cephalopods. Thus, we evaluated whether the 5′ end region of the 16S rRNA gene can be suitable as a DNA barcode marker among these taxa. Using a novel primer set, 28 different species were evaluated based on the pairwise intra- and interspecific distance and neighbor-joining (NJ) analysis. Except for Enteroctopus dofleini, we were able to obtain the sequences for the remaining species which formed highly supported clusters in the NJ tree. Divergence at the interspecific level may indicate high genetic variation of the region being proposed as compared to the standard of 16S rRNA. In addition, two well-supported clades and high levels of divergence within Sthenoteuthis oualaniensis, Loliolus japonica and Sepia pharaonis suggest the occurrence of cryptic species. This study confirms the efficiency of the 5′ end region of the 16S rRNA gene as a DNA barcode marker which can be used along with the standard DNA markers in future studies.

The neon flying squid, Ommastrephes bartramii is broadly distributed in subtropical and temperate regions of the world’s oceans. The North Pacific population is comprised of two spawning cohorts; the autumn cohort and winter-spring cohort, which despite their apparent contiguous hatching periods, have marked differences in the mantle length between the two cohorts, indicating differences in behavior. Especially, females of the autumn cohort after remaining in the subtropical zone for spring, in the first half of the summer migrate close to the vicinity of the southern boundary of the transition area. Subsequently they migrate into the subarctic waters to feed. However, for males details are less clear and it is considered that they remain in the subtropical zone without migrating to the subarctic feeding area. However little is known about the migration strategy of O. bartramii. Stable isotope profiles along the gladius (internal chitinous shell) have been recently analyzed and form a promising tool to back-calculate a chronological record of changes in the diet and habitat. In this study, δ13C and δ15N values were measured along the gladius to reconstruct the feeding variations and habitat of the autumn cohort during ontogeny. The results of δ13C values support previous studies which inferred differences in migratory behavior between males and females. These differences occurred from 260 mm mantle length.

Studies on the relationships between the early life stages of the neon flying squid Ommastrephes bartramii and oceanographic conditions are essential for understanding the spatial and temporal distribution patterns of this ecologically and economically important species. In this study, O. bartramii eggs were artificially fertilized and incubated at temperatures found in its known distribution range (16−26°C). Complete organogenesis with normal successive cleavage and the distinct continuity of morphological features was limited to between 18 and 25°C. Experimental rearing, cruise-collected specimens, and oceanographic data confirmed that the optimal temperature range for paralarval survival around Hawaii is 18 to 25°C. Embryos reared at 16°C showed abnormal organogenesis; however, normal development resumed when the embryos were transferred to 22 or 24°C after blastoderm formation. Hatchlings showed a variety of swimming behaviors, which may allow squid to regulate their thermal distribution in the wild. Furthermore, ball formation and associated chromatophore expansion might represent an apo sematic adaptation to imitate unpalatable prey. This study highlights the flexible strategy of O. bartramii embryo development and illustrates how information on paralarval behavior and oceanographic data (sea surface temperature) may be combined to improve our understanding of the factors that influence the survival of this species.

Our examination of the neon flying squid (Ommastrephes bartramii) winter–spring cohort catch per unit effort (CPUE, an index of stock) revealed significant positive correlations with the interannual variations of observed chlorophyll-a (Chl-a) concentration and autumn–winter mixed layer depth (MLD) in the winter–spring feeding grounds of paralarvae and juveniles (130–170°E, 20–27°N). These correlations suggest the importance of integrated bottom-up effects by the autumn–winter MLD for the neon flying squid stocks. However, the influence of autumn–winter MLD interannual variation in the forage availability for paralarvae and juveniles, i.e., particulate organic matter and zooplankton, has still been unclear. In this study, we use the lower trophic ecosystem model NEMURO, which uses the physical environmental data from the ocean reanalysis dataset obtained by the four-dimensional variational (4DVAR) data assimilation method. The model-based investigation enables us to clarify how the autumn–winter MLD controls the particulate organic matter and zooplankton abundance in the feeding grounds. Further, our investigation of the autumn–winter MLD interannual variation demonstrates that the stronger autumn wind in the feeding grounds develops a deeper mixed layer. Therefore, the deep mixed layer entrains nutrient-rich water and enhances photosynthesis, which results in good feeding conditions for paralarvae and juveniles. Our results underline that the wind system interannual variation has critical roles on the winter–spring cohort of the neon flying squid stock.

Ommastrephidae are the most important commercial fishery group among cephalopods. However, little is known about their embryonic development. This article provides details of embryonic development observed in three ommastrephids: Ommastrephes bartramii, Sthenoteuthis oualaniensis, and Eucleoteuthis luminosa. All embryos were obtained through artificial fertilization conducted onboard the research vessel Kaiyo Maru during a cruise around the Hawaiian Islands in December 2013. The embryonic and paralarval stages of O. bartramii are explained in detail. The hatchling stages were compared between all three species, as well as with information on Illex argentinus hatchlings from the literature. The species-specific effects of the oviducal gland powder on chorion expansion were analyzed. The results indicated that the overall chemical nature of the oviducal gland was species specific, although the inducer of chorion expansion was the same across species. In addition, treatment with oviducal gland jelly induced partial parthenogenesis in the early stages of embryonic development through the expansion of the perivitelline space and blastodisc formation.

Summary: The neon flying squid, Ommastrephes bartramii, is an oceanic squid species that is widely distributed in the North Pacific, with the winter-spring cohort spawning around the Hawaiian Islands. Here, we investigated the spawning characteristics of O. bartramii by analyzing various reproductive parameters of individuals (622 males, 108 females) collected in this region. Female spawning status was determined from the somatic indices and histological characteristics of the ovaries. At all developmental stages, the ovaries of spawned females contained oocytes, and oviduct fullness was not correlated with body size. Thus, because the eggs mature asynchronously, with multiple filling and evacuation events, this species is considered an intermittent spawner. Mature males with developed accessory glands were also present within the distribution range of healthy spawned females, indicating that mating occurs between spawning events. Our data indicate that the first spawning event occurs at a mantle length of ~520-540 mm for Hawaiian O. bartramii. Subsequently, the squid forage and grow, and refill the oviducts, before the second spawning event occurs.

In this study, we found that there were significant positive correlations between the catch per unit effort (CPUE, a squid abundance index) for the neon flying squid (Ommastrephes bartramii) winter–spring cohort and the satellite-derived chlorophyll a concentrations in their spawning grounds located at 140–160°E where 21°C

The lipids and fatty acids of the Humboldt squid (Dosidicus gigas) were examined to assess its lipid physiology and the relationship between the squid and its prey. Similar to highly migratory fishes, D. gigas has high levels of 22:6n-3 (DHA) in its TAGs (21.9–29.0% for mantles and 21.8–23.9% for arms), different from stomach content lipids (1.9–16.5%), which fluctuated or were at very low levels in some samples. The major PUFA in the tissue (mantle, arm, integument, and gonad) phospholipids were 20:5n-3 (icosapentaenoic acid, EPA), and DHA. Markedly high levels of both EPA and DHA with noticeable levels of 20:4n-6 (arachidonic acid; ARA) were observed in phosphatidylethanolamine (17.2–28.8% for EPA, 8.8–22.6% for DHA, and 2.4–11.8% for ARA), while DHA was found as a major component in phosphatidylcholine (30.6–47.8% for DHA). These findings imply a concentration of these PUFA from the storage lipids in the tissues of D. gigas, and that the squid actively concentrates EPA and in particular DHA as a top predator, similar to highly migratory fishes. D. gigas is a healthful marine food containing high levels of EPA and DHA with noticeable levels of ARA.

Squids of the family Ommastrephidae are distributed worldwide, and the family includes many species of commercial importance. To investigate phylogenetic relationships among squid species of the family Ommastrephidae, partial nucleotide sequences of two mitochondrial gene loci (cytochrome c oxidase subunit I [1277bp] and 16S rRNA [443bp]) of 15 ommastrephid species and two outgroup species from the families Loliginidae and Enoploteuthidae were determined and used to construct parsimony and distance based phylogenetic trees. The molecular data provided several new phylogenetic inferences. The monophyletic status of three subfamilies (Illicinae, Todarodinae and Ommastrephinae) was well supported, although phylogenetic relationships between the subfamilies were not resolved. Inclusion of a problematic species, Ornithoteuthis volatilis, to Todarodinae was indicated. Within Todarodinae, the Japanese common squid Todarodes pacificus was observed to have much closer relationship to the species of the genus Nototodarus than to its congener (Todarodes filippovae). These results indicate that re-evaluation of several morphological key characters for ommastrephid taxonomy may be necessary.

Villanueva, Roger ... et al. 9 pages, 2 figures, 1 table In vitro fertilization of oceanic squid is a necessary step to develop their larval culture and creates new opportunities to study and understand cephalopod development, taxonomy and ecology. The techniques described here in the form of a laboratory guide represent an attempt to refine and standardize the general methodology by indicating suitable laboratory materials, sources and preservation of gametes, and methods for fertilization and egg incubation. Twelve oceanic squid species have been fertilized in vitro to date; we outline a generalized experimental protocol and suggest that the reader consider particular species-specific modifications. Inadequate egg chorion expansion and premature hatching are identified as major challenges for in vitro fertilization. Recommendations for future research include studies on optimal gamete concentration, gamete preservation and determination of the functions of female oviducal and nidamental glands. The greatest obstacles to improving fertilization success in squids are the lack of standard methodologies and the paucity of information on both endogenous and exogenous factors controlling the fertilization process. This review is a first step toward overcoming these challenges We would like to acknowledge CIBNOR and the organizers of the 5th International Symposium on Pacific Squid for the stimulating days spent in La Paz, Mexico, which resulted in the preparation of this manuscript. RV was funded by the research project CALOCEAN (AGL2009-11546) from the Ministry of Science and Innovation of Spain and RdeS by COFAA and EDI grants

全世界の亜熱帯から温帯域に広く分布するアカイカの，南北大洋間の遺伝的差異を明らかにすることを目的に，北太平洋と南大西洋で採集された各 50 個体を用い，mtDNA 16S rRNA 領域（506 bp）の塩基配列分析を行った。その結果，13 種類のハプロタイプが検出され，北太平洋標本群と南大西洋標本群では共通するハプロタイプをもたず，3 つのサイトにおいて異なる塩基の固定がみられた。Exact test の結果は p

Interannual changes in abundance of the autumn cohort of neon flying squid Ommastraphes bartramii during 1979 to 2006 were examined in relation to the large-scale climate shift in the central North Pacific Ocean. Catch per unit of effort (CPUE) of driftnet surveys, which is assumed to reflect the squid stock level, was very low during 1999 to 2002, which was an anom- alous climate period. Given that the autumn cohort uses productive areas near and north of the transition zone chlorophyll front (TZCF) as favorable nursery and feeding grounds, we examined 3 covariates — (1) the winter position of the TZCF in the neon flying squid nursery ground, (2) the summer position of the TZCF in the feeding ground and (3) fishing mortality — to estimate which covariates were significantly correlated with low CPUE time periods. Multiple linear regression analysis suggested that only the effect of winter position of the TZCF in the nursery ground best predicted the change in the CPUE. The anomalous climate conditions caused a significant reduc- tion in net primary production over an extended area within the subtropical frontal zone (STFZ), which is the main nursery ground for the autumn cohort. Hence, we assume that food availability for juvenile neon flying squid could be critical for the level of stock recruitment of this cohort. Fur- thermore, the sea level anomaly (SLA), which is considered to be a useful index of variability in the upper ocean structure, significantly correlated to the CPUE during spawning and nursery periods in the STFZ. Our study supports the hypothesis that the bottom-up effect of the climate shift can be manifested rapidly in neon flying squid, indicating that squid abundance can act as a productivity integrator and a real-time ecosystem indicator that respond to large-scale environ- ment changes.

This study examined the rate of fertilization in the Argentine shortfin squid Illex argentinus after artificial insemination using sperm from different sources, as well as the effect of cold-storage on the fertilization capacity of gametes from mature squids, and the impact of mechanical agitation on embryonic development. In addition, the process of chorionic expansion during the course of embryonic development was also examined. High fertilization rates were obtained from spermatophores (76– 95%) and spermatozoa from the vas deferens (73–87%), but no fertilization was observed using spermatozoa from testes. Female and male gametes stored at 0°C had a high fertilization capacity (>72%) within 24 h. Embryos (stages 4 to 17; 3 to 61 h at 20 o C) subjected to mechanical agitation at a critical period (stages 5 to 12; 5 to 20 h at 20 o C) exhibited high mortality and abnormal development. In the course of embryonic development, the chorion expanded four times: once at fertilization and then at developmental stages 15–16, 17–21, and finally at stages 25–27. The growth rate of the third expansion corresponded with an increase in embryonic body length. To improve the fertilization rate and increase the production of healthy paralarvae in on-board experiments, factors such as the origin of spermatozoa, gamete storage methods, and the handling of fertilized eggs during the critical period should be carefully controlled.

We compared the diet of Ommastrephes bartramii paralarvae with morphological changes in their beaks and proboscis (fused tentacles). The paralarvae were collected north of the Hawaiian Islands during 2001 and 2002 and ranged in mantle length (ML) from 1.1 to 13.2 mm. They fed on crustaceans, including copepods (copepodite stage) and amphipods. The rostral tips of upper and lower beaks began to protrude anteriorly at around 3–4 mm ML, and the smallest paralarva with identifiable prey in its digestive tract was 4.2 mm ML, which suggests that the paralarvae can masticate prey soon after the beaks protrude. The proboscis separated into two tentacles at 9.3–13.2 mm ML, but the newly formed tentacles were weakly developed even in the largest specimen, suggesting that tentacles do not operate functionally and that the arms are used to capture prey.

Diet and sexual maturation were examined in the winter–spring cohort of the neon flying squid, Ommastrephes bartramii, during its southward migration through the Kuroshio–Oyashio transition region of the western North Pacific. The main prey items are micronektonic animals and small pelagic fish, which were abundantly distributed throughout the study area. Among the prey species, O. bartramii was dependent on the Japanese anchovy Engraulis japonicus, which also migrate from the northern to southern transition region during the winter, and the micronektonic squid Watasenia scintillans throughout the study period. Other common prey items were Gonatopsis borealis, Diaphus theta, and Ceratoscopelus warmingii from October to November or December, and Tarletonbeania taylori after December. These dietary changes can be explained by the difference in the seasonal north–south migration patterns of the predator and prey species. Male sexual maturation progressed throughout the season, and most individuals were fully mature in January. In contrast, most of the females were immature throughout the study period. The feeding strategy of the squid in relation to their seasonal north to south migration and sexual maturation was discussed.

It has been claimed that most squid species in the genus Onykia may be immature stages of species in the genus Moroteuthis. To evaluate the generic status of Moroteuthis and Onykia and to identify paralarvae collected in northern Hawaiian waters, we performed morphological investigation and nucleotide sequence analysis of the mitochondrial cytochrome oxidase I (COI) gene. Of 42 Onykia paralarvae (1.8–8.5 mm dorsal mantle length, DML) examined, 41 had a nucleotide sequence identical to that of M. robusta and one (designated Onykia sp. A) could not be assigned to any known Moroteuthis species. Nucleotide sequence diversity estimates based on Kimura's two-parameter distances between Onykia sp. A and Moroteuthis spp. (0.109–0.150) fell well within the range of congeneric species, suggesting that Onykia sp. A is a member of the genus Moroteuthis. Molecular data supported the conclusion that the genus Moroteuthis is a junior synonym of the genus Onykia. Morphological investigation revealed that paralarvae of O. robusta (= M. robusta) Onykia paralarvae in the chromatophore pattern on the mantle. The key characters for distinguishing O. robusta paralarvae from Onykia sp. A were the number and arrangement of chromatophores on the funnel.

The gempylid Nesiarchus nasutus is reported for the first time from Argentinean waters, the southernmost occurrence of the species in the Southwestern Atlantic. This suggests that the fluctuating environmental characteristics of the area would be proper for the presence of tropical and subtropical species. A ocorrência de Nesiarchus nasutus é registrado pela primeira vez em águas argentinas, sendo a esta ocorrência mais meridional da espécie no Atlântico Sudoeste. Isto sugere que as características ambientais flutuantes da área seriam adequadas para a presença de espécies tropicais e subtropicais na mesma. Fil: Spath, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Delpiani, Gabriela Elina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Brunetti, N. E.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Sakai, M.. National Research Institute of Far Seas Fisheries; Japón Fil: Figueroa, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda. Of these, about 30–40 squid species have substantial commercial importance around the world. Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off. The present overview describes all substantial squid fisheries around the globe. The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide. The history and fishing methods used in squid fisheries are also described. Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management.

A total of 110 adult individuals from four ommastrephid (family Ommastrephidae) squid species (Ommastrephes bartramii, Sthenoteuthis oualaniensis, Eucleoteuthis luminosa, and Hyaloteuthis pelagica) were used to obtain diagnostic DNA markers for species identification. Restriction fragment length polymorphism (RFLP) analysis of a partial segment (855 bp) of the mitochondrial DNA cytochrome oxidase I (COI) gene amplified by polymerase chain reaction (PCR) revealed that the restriction profiles of two endonucleases (Alu I and Tsp509 I) were diagnostic for species identification. The restriction assay partially supplemented with nucleotide sequence analysis successfully assigned 69 damaged and morphologically equivocal ommastrephid paralarvae collected in northern Hawaiian waters, identifying 60 O. bartramii, eight S. oualaniensis, and one E. luminosa. The family Ommastrephidae appears to be monophyletic. Although the phylogenetic relationships among genera were not resolved well due to apparent homoplasy and large genetic divergence between species, COI sequence data without transitions provided support for subfamily level relationships.

Marine mammals are top predators in marine ecosystems and bioaccumulate various trace elements that pass through the food web (Miles and Hills 1994; Wagemann and Stewart 1994; Dietz et al. 1996). Trace elements include both essential and non-essential metals. Iron (Fe) and zinc (Zn) are essential metals that occur widely and abundantly in living organs. The concentrations at which they occur in an animal are affected not only by the diet, age, nutritional stress but also health status of the animal. In mammals, it is possible to examine element accumulation using their teeth. During dentine formation, trace elements are removed from dietary and environmental sources, and incorporated into the crystalline apatite structure of the teeth. Here, unlike in bones, they are not subject to reabsorption or remodeling, so they can be used to examine an animal’s life history. Ando et al. (2005) found significant long-term differences in Zn/calcium (Ca) and Fe/Ca ratios from 1968 to 1999 by particle-induced X-ray emission analysis (PIXE). And Zn/Ca and Fe/Ca ratios were higher in younger males than older males, but showed no trend with age in females. There are question about fluctuation of these metals within each animal. In this study, we examined the canine teeth of Steller sea lions (Eumetopias jubatus) to assess their action and the fluctuation of essential metals of that occur in the teeth with their each life history.

The neon flying squid (Ommastrephes bartramii), which is the target of an important North Pacific fishery, is comprised of an autumn and winter–spring cohort. During summer, there is a clear separation of mantle length (ML) between the autumn (ML range: 38–46 cm) and the winter–spring cohorts (ML range: 16–28 cm) despite their apparently contiguous hatching periods. We examined oceanic conditions associated with spawning/nursery and northward migration habitats of the two different-sized cohorts. The seasonal meridional movement of the sea surface temperature (SST) range at which spawning is thought to occur (21–25°C) indicates that the spawning ground occurs farther north during autumn (28–34°N) than winter–spring (20–28°N). The autumn spawning ground coincides with the Subtropical Frontal Zone (STFZ), characterized by enhanced productivity in winter because of its close proximity to the Transition Zone Chlorophyll Front (TZCF), which move south to the STFZ from the Subarctic Boundary. Hence this area is thought to become a food-rich nursery ground in winter. The winter–spring spawning ground, on the other hand, coincides with the Subtropical Domain, which is less productive throughout the year. Furthermore, as the TZCF and SST front migrate northward in spring and summer, the autumn cohort has the advantage of being in the SST front and productive area north of the chlorophyll front, whereas the winter–spring cohort remains to the south in a less productive area. Thus, the autumn cohort can utilize a food-rich habitat from winter through summer, which, we hypothesize, causes its members to grow larger than those in the winter–spring cohort in summer.

Cephalopods are a relatively small class of molluscs (~800 species), but they support some large industrial scale fisheries and numerous small-scale, local, artisanal fisheries. For several decades, landings of cephalopods globally have grown against a background of total finfish landings levelling off and then declining. There is now evidence that in recent years, growth in cephalopod landings has declined. The commercially exploited cephalopod species are fast-growing, short-lived ecological opportunists. Annual variability in abundance is strongly influenced by environmental variability, but the underlying causes of the links between environment and population dynamics are poorly understood. Stock assessment models have recently been developed that incorporate environmental processes that drive variability in recruitment, distribution and migration patterns. These models can be expected to improve as more, and better, data are obtained on environmental effects and as techniques for stock identification improve. A key element of future progress will be improved understanding of trophic dynamics at all phases in the cephalopod life cycle. In the meantime, there is no routine stock assessment in many targeted fisheries or in the numerous by-catch fisheries for cephalopods. There is a particular need for a precautionary approach in these cases. Assessment in many fisheries is complicated because cephalopods are ecological opportunists and stocks appear to have benefited from the reduction of key predator by overexploitation. Because of the complexities involved, ecosystem-based fisheries management integrating social, economic and ecological considerations is desirable for cephalopod fisheries. An ecological approach to management is routine in many fisheries, but to be effective, good scientific understanding of the relationships between the environment, trophic dynamics and population dynamics is essential. Fisheries and the ecosystems they depend on can only be managed by regulating the activities of the fishing industry, and this requires understanding the dynamics of the stocks they exploit.

A previously observed electron line at INS at 330.3±0.4 keV in e++Th interactions has been implied by these authors to originate from the decay of an unknown neutral object X0. QED predicts a two-photon decay mode of X0 leading to a correlated two-photon coincidence peak at 841.3±0.4 keV. To search for such a peak γγ-coincidence experiments were performed. From an observed peak-like structure in the spectrum at 841.7±0.3 keV and an associated cross section of 10.6±3.1 (stat) ± 6.9 (syst) μb an upper limit for the cross section of 15.2±1.5 (syst) μb for the production and 2γ decay of the X0 was deduced with a statistical confidence level of 95%.

The neon flying squid, Ommastrephes bartramii, is an oceanic squid species that is widely distributed in the North Pacific, with the winter-spring cohort spawning around the Hawaiian Islands. Here, we investigated the spawning characteristics of O. bartramii by analyzing various reproductive parameters of individuals (622 males, 108 females) collected in this region. Female spawning status was determined from the somatic indices and histological characteristics of the ovaries. At all developmental stages, the ovaries of spawned females contained oocytes, and oviduct fullness was not correlated with body size. Thus, because the eggs mature asynchronously, with multiple filling and evacuation events, this species is considered an intermittent spawner. Mature males with developed accessory glands were also present within the distribution range of healthy spawned females, indicating that mating occurs between spawning events. Our data indicate that the first spawning event occurs at a mantle length of ~520-540 mm for Hawaiian O. bartramii. Subsequently, the squid forage and grow, and refill the oviducts, before the second spawning event occurs. La pota saltadora, Ommastrephes bartramii, es una especie de calamar oceánico que se encuentra ampliamente distribuido en el Pacífico Norte, con la cohorte de desove de invierno-primavera situada alrededor de las islas Hawai. El presente estudio investiga las características de desove de O. bartramii mediante el análisis de diversos parámetros reproductivos de ejemplares (622 machos, 108 hembras) recolectados en esa región. El nivel de desove de las hembras se determinó a partir de índices somáticos y características histológicas de sus ovarios. En todos los estadios de desarrollo, los ovarios de las hembras desovantes contenían oocitos, en tanto que el grado de llenado de los oviductos no se correlacionó con el tamaño del cuerpo. Así, debido a que los oocitos maduran de forma asincrónica, con múltiples eventos de llenado y liberación, se considera a esta especie como desovante intermitente. Se recolectaron machos maduros con glándulas accesorias desarrolladas en el rango de distribución de las hembras desovantes, indicando que las cópulas se producen entre estos eventos de desove. Nuestros datos indican que en O. bartramii de la zona de Hawaii el desove inicial se produce a ~520-540 mm de longitud del manto. Posteriormente, el calamar se alimenta y crece, volviendo a rellenar sus oviductos antes de que aparezca el segundo evento de desove.

A potentially appealing alternative to the traditional fabrication process of TiO2 film electrodes for dye-sensitized solar cells (DSSCs) was presented by utilizing water-soluble TiO2 composite pastes containing size-controlled ink particles (SIPs) isolated from the squid. The mixture ratios of SIPs in the paste formulations affected the photoelectric conversion efficiency (PCE). The highest PCE was achieved when the mixture ratio of SIPs was 20%. The process is highly reproducible and leads to a 35% increase in PCE compared with that in the DSSC without SIP addition. The utilization of SIPs in the fabrication of TiO2 film electrodes enhanced the performance of DSSCs.

The reported 330-keV electron line in positron scatterings on a Th target has been reinvestigated by using the positron emitter [sup 82]Sr in place of [sup 118]Te, employed in previous experiments. We have observed the same line with an energy of 330.1[plus minus]0.4 keV and a cross section of 158[plus minus]0.22[plus minus]0.25 mb. The full width at half maximum is less than 2.1[plus minus]0.3 keV, which is limited by the instrumental resolution. The experimental results agree with the previous ones.

Masu salmon fry Oncorhynchus mason of two different origins, Chilean stock (MC) of 7.0g size parr and Japanese stock (MJ) of 4.9g size parr, were released in February 1987 and in October 1987, respectively, into a tributary of Lake General Carrera in Chilean Patagonia. The spawning run of the salmon (299 females and 276 males) was observed in the river from March to April 1989. The sex ratio (males per female) was regarded as nearly 1.0, and this suggested that river-resident precocious males were very scarce in the river. Mean fork lengths and weights of spawners were 56.3cm and 1, 715g, respectively. The rate of return was estimated as 1.07% for MC and 0.95 for MJ. No difference between either rate was observed though they were released at different sizes and times. Eyed-stage eggs and alevins were found in the river after the spawning season. These indicated that there is a high possibility of population establishment in the lake by the small parr release of masu salmon.

The North Pacific Ocean population of the neon flying squid Ommastrephes bartramii, which un- dertakes seasonal north-south migrations, consists of autumn and winter-spring spawning cohorts. We ex- amined life history differences between the 2 cohorts in relation to the oceanographic environment. The differ- ences could be explained by seasonal north-south movements of the following 2 oceanographic zones: (1) the optimum spawning zone defined by sea surface temperatures; and (2) the food-rich zone defined by the position of the transition zone chlorophyll front (TZCF). The 2 cohorts use the food-rich zone in different phases of their life cycles. The spawning grounds for the au- tumn cohort occur within the subtropical frontal zone (STFZ), characterized by enhanced productivity in win- ter due to its proximity to the TZCF, whereas the spawning grounds for the winter-spring cohort occur within the subtropical domain, which is less productive. As the TZCF shifts northward in spring, the autumn co- hort continues to occur in the productive area north of the TZCF, whereas the winter-spring cohort remains in the less productive area to the south until it migrates into productive waters north of the TZCF in the summer or autumn. Consequently, the autumn cohort grows faster than the winter-spring cohort during the first half of its life cycle, whereas the winter-spring cohort grows faster during the second half. This growth pat- tern may be responsible for differing migration pat- terns; males of the autumn cohort do not have to migrate given their early fast growth in the STFZ, whereas those of the winter-spring cohort must mi- grate to the food-rich subarctic frontal zone to compen- sate for their slow growth. These biological and eco- logical differences between the 2 cohorts suggest flexibility of their life history response to oceanographic environments. Hatchling of the neon flying squid Ommastrephes bartramii

The previously reported 330.8\ifmmode\pm\else\textpm\fi{}1.0-keV electron line in ${\mathit{e}}^{+}$+Th interactions has been reinvestigated to confirm its existence. We have made a definite observation of the relevant peak with an energy of 330.1\ifmmode\pm\else\textpm\fi{}0.3 keV, a fullwidth at half maximum of less than 1.7\ifmmode\pm\else\textpm\fi{}0.7 keV and a cross section of 160(1\ifmmode\pm\else\textpm\fi{}0.19\ifmmode\pm\else\textpm\fi{}0.25) mb. We have assigned the generation site of the electrons to the Th target by comparing the energy shift and the shape change of the line with those of the neighboring conversion lines in the spectra taken under different scattering conditions.

Two notacanthiform Tiluropsis type leptocephali are analysed, thus constituting the southernmost report in the Atlantic Ocean. Specimens are compared with others of the kind taken from the literature. Some considerations about their larvae and Halosauridae, the family they would belong to, are supplied.

To identify sub-daily or aperiodic increments of statolith growth in the ommastrephid squid Illex argentinus, we examined statolith microstructure, especially with regard to the natal ring, where counting of daily growth increments should begin, and the widths of subsequent daily increments. Paralarvae obtained by artificial fertilisation were incubated on board at different temperatures ranging from 11.4 to 25.4°C, and were starved throughout the experiments. We observed statolith growth from newly hatched to 10-day-old paralarvae and used alizarine complexone staining to attempt validation of the growth. The maximum statolith radius (MSR) of newly hatched paralarvae was constant at 21.1 μm across the full range of temperatures, with the exception of 25.4°C. Daily growth of MSR was analysed separately in two phases, the pre-yolk-absorption phase (i.e. yolk sac still present) and the post-yolk-absorption phase. During the pre-yolk-absorption phase, the daily growth rate (DGR, y) of the MSR varied from 3 to 7 μm day–1 depending on rearing temperature (x) and was expressed as y = 0.37x – 1.77. We concluded that the natal ring forms at 21 μm MSR. The initial increment width obtained from the DGR of MSR seems applicable for distinguishing daily rings from sub-daily rings, although this application should be limited to hatchling paralarvae in the pre-yolk-absorption phase.

XMA plane analysis on an anodic oxide film of an Al-Mn alloy plate indicates that the parts of high density manganese(area percentage 15.8%)are dispersed lake islands. SEM observation on an anodic oxide film(the electrolytic potential 500V)of an Al-Mn alloy shows that the some parts of high density manganese are dropped out from the anodic oxide film during anodization. ESCA depth profile indicates that manganese content in the anodic oxide film is less than the bulk content(1.10wt% of Mn).