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We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35 degree -45 degree N and 150 degree -175 degree E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Nina events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Nino year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Nina event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Nino event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable insights into exploring the relationship between the underlying squid habitat and the inter-annual environmental change.

Cephalopod paralarvae were collected in the southeast–south Brazilian outer shelf and continental slope (24°–34°S) from 2009 to 2015 to evaluate their distribution and abundance in relation to water masses during Autumn and Spring seasons. A total of 801 paralarvae were caught with Bongo nets (500 µm mesh) in oblique tows at sample depths of up to 250 m. Fourteen families, 22 genera, and 15 species were identified. The most abundant families were Argonautidae (40.1%), Ommastrephidae (31%), and Enoploteuthidae (23.7%). The highest abundances were recorded on Autumn 2014 (667 ind 1000 m −3 ) and Argonauta nodosus was the most abundant species in the study area (437 ind 1000 m −3 ). Ommastrephes sp., Illex argentinus , and Abralia spp. paralarvae were also abundant (124, 131, and 135 ind 1000 m −3 , respectively) during Spring 2009, 2010, and 2014, respectively. These species were collected under the influence of Tropical Water (TW), Subtropical Shelf Water (STSW), and South Atlantic Central Water (SACW). Illex argentinus and Ommastrephes sp. paralarvae occupy different niches. The latter was significantly more abundant in the northern area, in TW and TW + SACW water masses, while I. argentinus was more abundant in the outer southern shelf, in the STSW. This is the first study evaluating the composition, distribution, and abundance of cephalopod paralarvae in the study area, while also providing the first record of Bolitaena pygmaea, Egea inermis, Pterygioteuthis sp., and Promachoteuthis sp. paralarvae.

The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the trophic ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the trophic ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.

Molecular identifications based on two mitochondrial markers (cytochrome c oxidase subunit I -COI- and 16S ribosomal RNA gene -16S-) have been implemented to confirm the morphological identification of eight specimens collected in the Central western Mediterranean. Molecular data show they belonged to a recently resurrected species of the genus Ommastrephes , i.e., O. caroli , known to be distributed in the Atlantic Ocean and Mediterranean Sea. Despite this, molecular analyses of COI sequences evidenced the presence of potential genetic differentiation between Mediterranean and Atlantic samples, highlighting the need for further studies, with more individuals to investigate the connectivity between individuals living in the two areas. Furthermore, morphological, biometric and reproductive features here reported, could be useful in evaluating possible distinctive biological features between the Mediterranean and Atlantic individuals. Female mature size was larger than the male. The relationships obtained between the beak measurements and body sizes (DML; TW) were better described by a power model. Asynchronous oocytes development with relatively small oocytes (0.05–1.10 mm) and a protracted intermittent spawning with active feeding were observed. This study also reported for the specie O. caroli the first data on the potential fecundity estimated (840061 oocytes), the oviducal load (90000 ripe oocytes) as well as the number of seminal receptacles and the size and morphology of the spermatangia found in the buccal mass of all mated females. Even if on a low sample size, beaks and eye lenses were used for the first time in O. caroli for age estimation. The statistically significant relationship found between increments counted in eye lenses and beaks highlighted the reliability of the lenses to estimate age in O. caroli , even if further studies will be needed for its validation. Assuming a daily increment for both structures, a mean life span of about 12–13 months was estimated for both sexes, which is consistent with the sexual maturity condition observed in all the samples and the semelparity known for cephalopods coleoids.

Mesoscale eddies are ubiquitous in global oceans yielding significant impacts on marine life. As a short-lived pelagic squid species, the population of neon flying squid ( Ommastrephes bartramii ) is extremely sensitive to changes in ambient oceanic variables. However, a comprehensive understanding of how mesoscale eddies affect the O. bartramii population in the Northwest Pacific Ocean is still lacking. In this study, a 10-year squid fisheries dataset with eddy tracking and high-resolution reanalysis ocean reanalysis data was used to evaluate the impact of mesoscale eddies and their induced changes in environmental conditions on the abundance and habitat distribution of O. bartramii in the Northwest Pacific Ocean. A weighted-based habitat suitability index (HSI) model was developed with three crucial environmental factors: sea surface temperature (SST), seawater temperature at 50-m depth (T 50m ), and chlorophyll-a concentration (Chl-a). During years with an unstable Kuroshio Extension (KE) state, the abundance of O. bartramii was significantly higher in anticyclonic eddies (AEs) than that in cyclonic eddies (CEs). This difference was well explained by the distribution pattern of suitable habitats in eddies derived from the HSI model. Enlarged ranges of the preferred SST, T 50m, and Chl-a for O. bartramii within AEs were the main causes of more squids occurring inside the warm-core eddies, whereas highly productive CEs matching with unfavorable thermal conditions tended to form unsuitable habitats for O. bartramii . Our findings suggest that with an unstable KE background, suitable thermal conditions combined with favorable foraging conditions within AEs were the main drivers that yielded the high abundance of O. bartramii in the warm eddies.

Oceanic squids are typical species that sensitive to the environment change. Previous studies on oceanic squids mainly focus on its annually fluctuated abundance under the background of climate change. The changes of individual morphological sizes, including body and beak, have been observed in recent years. In this study, Ommastrephes bartramii, an important cephalopod species in North Pacific Ocean, has been selected to analyze the annual morphological changes of body and beak under different scales of climate events. Geometric morphometrics was used to analyze the shape variations of both upper beak and lower beak. The possible phenotypic plasticity of body and beak was also discussed in different aspects. Body size showed different variations among different climatic years. The size at the maturity stage in 2015 (El Niño year) was much smaller than that in other years for both sexes. The centroid size representing the beak size showed the significant difference between two types of Pacific Decadal Oscillation phases. The shapes of upper and lower beaks showed significant differences between small-scale climatic patterns in which El Niño or La Niña event occurred, displaying different growth patterns.

Sepia ink polysaccharide (SIP) isolated from squid and cuttlefish ink is a kind of acid mucopolysaccharide that has been identified in three types of primary structures from squid (Illex argentinus and Ommastrephes bartrami), cuttlefish Sepiella maindroni, and cuttlefish Sepia esculenta ink. Although SIP has been proved to be multifaceted, most of the reported evidence has illuminated its chemopreventive and antineoplastic activities. As a natural product playing a role in cancer treatment, SIP may be used as chemotherapeutic ancillary agent or functional food. Based on the current findings on SIP, we have summarized four topics in this review, including: chemopreventive, antineoplastic, chemosensitive, and procoagulant and anticoagulant activities, which are correlative closely with the actions of anticancer agents on cancer patients, such as anticancer, toxicity and thrombogenesis, with the latter two actions being common causes of death in cancer cases exposed to chemotherapeutic agents.

We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40 degree N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44 degree N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160 degree W-180 degree ) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180 degree -160 degree W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable insights into exploring the relationship between the underlying squid habitat and the inter-annual environmental change.

Ommastrephid squids are migratory and economically important species in the Pacific Ocean. Pelagic squids have a short lifespan and are highly affected by climate change. Understanding the ontogenetic dispersal of squids under environmental fluctuations can ensure proper and scientific management of these species. Samples of neon flying squid (Ommastrephes bartramii) and jumbo flying squid (Dosidicus gigas) were collected in the Northwest Pacific and Southeast Atlantic (offshore waters of Peru) oceans, respectively, in different years. Then, five trace elements of the grounded statoliths were measured and quantified using laser ablation inductively coupled plasma‒mass spectrometry (LA-ICP‒MS) to determine their ontogenetic and inter-annual variations. Furthermore, the ontogenetic dispersals of the two squid species in different years were reconstructed. The results showed that for O. bartramii, the inter-annual differences in the Sr/Ca, Ba/Ca, and Na/Ca ratios were significant (P < 0.05). However, no significant inter-annual difference was observed in the Mg/Ca ratio (P > 0.05). For D. gigas, the inter-annual differences in the Sr/Ca, Mg/Ca, and Na/Ca ratios were significant (P < 0.05). However, no significant inter-annual difference was observed in the Ba/Ca ratio (P > 0.05). Sea surface temperature (SST) indicators were selected, including the Mg/Ca ratio for O. bartramii and Sr/Ca, Ba/Ca, and Na/Ca ratios for D. gigas, and regression models were estimated. Based on a Bayesian model, the high probability of occurrence of these indicators in a particular area represented the possible optimal location of squids, and the potential ontogenetic dispersals of the two squid species in different years were reconstructed. We found that the ontogenetic dispersals of the squids differed in different years. However, they migrated in the same direction. Nevertheless, El Niño–Southern Oscillation (ENSO) events affected the habitat position of squids and the size of their habitat area at each stage.