Ommastrephes Research Articles

Interannual and ontogenetic stage differences on trophic ecology of neon flying squid Ommastrephes bartramii inferred from stable isotope analyses in beaks

To reveal the interannual and ontogenetic stage variation of trophic ecology, different subsections of Ommastrephes bartramii beaks from different years were used for stable isotope analysis. The δ13C and δ15N values of beaks within different subsections showed significant differences between different years and different ontogenesis stages (P < 0.05). Different ecological overlap rates were found between different years and the overlap rate between 2012 and 2016 was larger than that of 2012 versus 2015 and 2015 versus 2016. The δ13C and δ15N values in 2015 were lower than those in 2012 and 2016 and represented a narrower isotope niche, whereas the ellipse area of isotope niche in 2015 was the widest and indicated that the food organisms preyed on by O. bartramii were in the lower trophic level, but the species of food organisms were more abundant in 2015. The stable isotope analyses in different growth stages showed that the niches in the larvae stage and paralarvae stage showed no significant difference between different years, indicating that the species of food organisms in the larvae stage and paralarvae stage were similar. However, with the growth of individual size, the isotopic niche gradually showed differences and developed towards a wider isotope niche in 2012 and 2016. During the El Niño event in 2015, the marine environment was not conducive to the growth of prey organisms and the poor environment might affect the feeding behavior of O. bartramii, resulting in the narrower isotope niche. During the normal years and the La Niña event, the environment was relatively suitable for O. bartramii and resulted a wider isotope niche.

Water Temperature at Different Depths Affects the Distribution of Neon Flying Squid (Ommastrephes bartramii) in the Northwest Pacific Ocean

Ommastrephes bartramii can vertically swim during its life, and previous studies have suggested the need to account for preferred habitat distribution influenced by water temperatures at different depths. To explore the impacts of deep-water temperature on O. bartramii spatial distribution, we constructed generalized additive models (GAMs) based on the Chinese squid-jigging fishery data and the Argo deep water temperature data during 2005–2018 in the Northwest Pacific Ocean to analyze the relationships between the local abundance of O. bartramii and deep-water temperatures. The results showed that the variables including surface water temperature (T0), water temperature at 30- and 100-m depths (T30 and T100), and water differences between T0 and T30 (D0–30) significantly affected the spatial distribution of O. bartramii. The suitable ranges of each variable are different, &amp;gt; 15.5°C for T0, 11–18°C for T30, &amp;lt; 6°C for T100, and 4–4.5°C for D0–30. The areas occupied by the suitable T30 seemed to reflect the outline of fishing ground, whereas the areas with suitable T100 were to indicate the high density of O. bartramii. The predicted suitable habitat area and high-density area for O. bartramii are also regulated by El Niño–Southern Oscillation (ENSO) events. We demonstrated how the estimates of O. bartramii spatial distribution would vary influenced by deep-water temperatures in the Northwest Pacific Ocean. This information may help develop an appropriate method for investigating the effects of deep-water temperature on species with vertical migration.

Influence of environmental data of different sources on marine species habitat modeling: A case study for Ommastrephes bartramii in the Northwest Pacific Ocean

Influence of environmental data of different sources on marine species habitat modeling: A case study for Ommastrephes bartramii in the Northwest Pacific Ocean

Interannual Abundance Fluctuations of Two Oceanic Squids in the Pacific Ocean Can Be Evaluated Through Their Habitat Temperature Variabilities

Neon flying squid (Ommastrephes bartramii) and jumbo flying squid (Dosidicus gigas) are two commercially essential oceanic squids in the Pacific Ocean. An in-depth understanding of the mechanisms of their annual and interannual abundance fluctuations under environmental and climate variabilities can ensure ration and suitable management. Thus, the annual and interannual abundance fluctuations of the stock of the western winter-spring cohort of O. bartramii and D. gigas off Peru Exclusive Economic Zone (PEEZ) waters and their association with habitat temperature variabilities are explored in this study based on the historical Chinese Squid-jigging fishery data from 2003 to 2020. The habitat temperature variabilities were defined as the effective principal components of the SST at the squids’ two important habitats (spawning and feeding ground) through life histories according to the principal component analysis. The Hodrick—Prescott filter analysis was conducted to quantify the annual and interannual fluctuations of abundance and habitat temperature variabilities. Furthermore, the generalized additive model (GAM) was employed to investigate their associations. The results demonstrated different but not synchronous trends of abundance for O. bartramii and D. gigas. Regarding O. bartramii, the interannual abundance first decreased (2003∼2013) and then increased (after 2014). For D. gigas, the interannual abundance kept decreasing within 2003∼2020. Their annual trends have presented large fluctuations over years. The results of GAM indicated that using habitat temperature variabilities only can trace the abundance trend of O. bartramii and D. gigas at an interannual but not annual scale. Further studies verified that Pacific Decadal Oscillation (PDO) is a crucial factor affecting the interannual abundance trend of these two squids through the habitat temperature variabilities. However, this study indicates that the habitat temperature variabilities not only are related to other large-scale factors, which are not investigated currently at an interannual scale, but also, are combined with other small- or middle-scale factors at an annual scale on their impacts to the abundance fluctuations of these two squids. Therefore, in order to better explain the mechanisms of annual and interannual abundance fluctuations of O. bartramii and D. gigas under environmental and climate variabilities, the importance of combining other potential factors into consideration is highlighted.

Climate-induced life cycle and growth variations of neon flying squid (Ommastrephes bartramii) in the North Pacific Ocean

Climate change has had large impacts on marine animals, including neon flying squid Ommastrephes bartramii (O. bartramii) in the North Pacific Ocean. O. bartramii statoliths from 2012, 2015, and 2016 were used to evaluate the variations in life cycle events. The relationship between mantle length and body weight showed significant differences between years and gender. The oldest squid was collected in 2016 at 271 days old, further proving that O. bartramii has nearly a 1-year life span. The hatching season ranged from December to May and the peak hatching time in 2015 was one-half month later than in 2012 and 2016. Growth rates varied with environmental factors such as sea surface temperature (SST) and chlorophyll a concentration (chl. a), indicating that higher SST and chl. a concentrations led to faster growth. An extreme El Niño event with lower SST in 2015 also led to younger age class and slower growth rates. The occurrence of differences in body size and growth rates between years, caused by the interannual variations of environmental factors, makes it necessary to use separate growth curves for different years when analyzing North Pacific O. Bartramii populations.

The Change Characteristics of Potential Habitat and Fishing Season for Neon Flying Squid in the Northwest Pacific Ocean under Future Climate Change Scenarios

AbstractClimate‐driven changes in the marine environment can impact the distribution and abundance of marine species. Here, we combined available commercial fishery data of the neon flying squid Ommastrephes bartramii in the traditional fishing grounds in the northwest Pacific Ocean collected by Chinese squid jigging vessels between 1996 and 2005 with the dominant environmental climate factors affecting its distribution. Fishery and dominant environmental climate factors were incorporated into a species distribution model (maximum entropy model, MaxEnt) to describe the suitable habitats for neon flying squid. Two climate change scenarios (RCP4.5 and RCP8.5) from the Community Earth System Model Version 1 were used with MaxEnt to project the future distribution of environmental suitability for neon flying squid. Results indicated that suitable neon flying squid habitat moved northward under climate change, and the projected area of suitable habitat decreased by the end of the century. Projections revealed that suitable habitats for neon flying squid will almost disappear between July and September by 2095 in RCP4.5, and between July and November (except in October, which increased by about 34%) in RCP8.5. These findings suggest that the fishing season for neon flying squid might be delayed and the total fishing time might be shortened. We suggest that adaptive fisheries management strategies, such as controlling fishing effort and setting a closed season, should be established as soon as possible in response to climate changes in the North Pacific Ocean.

Migration patterns and changes in hatching date of neon flying squid Ommastrephes bartramii distributed in the northwestern Pacific Ocean in early summer and caught in fishing grounds off the coast of northeastern Japan in winter

Migration patterns and changes in hatching date of neon flying squid Ommastrephes bartramii distributed in the northwestern Pacific Ocean in early summer and caught in fishing grounds off the coast of northeastern Japan in winter

The effects of spatiotemporal scale on commercial fishery abundance index suitability

Abstract With consideration of sophisticated modern commercial fisheries, the commonly used metric catch per unit effort (CPUE) may not be a reasonable proxy for generating abundance indices (AIs) for all species. Presumably, spatiotemporal scale is a critical factor that affects the accuracy of local/aggregated AIs derived from spatial modelling approaches, thus it is necessary to evaluate how scale affects scientific estimates of abundance. We explored three commonly utilized AI proxies, including aggregated catch (CatchAI), aggregated effort (EffortAI), and CPUEAI from the perspective of accuracy and spatial representational ability using a neural network (NN) model at different spatiotemporal scales. As a case example, we grouped the Chinese fleet's Northwest Pacific neon flying squid (Ommastrephes bartramii) fishery dataset (2009–2018) at four spatial scales (0.25° × 0.25°, 0.5° × 0.5°, 1° × 1°, 2° × 2°) to construct monthly and annual resolution models. The results showed that for both simulated and real datasets, AIs based on catch data had better accuracy, consistency, and spatial representational ability compared to CPUE and effort-dependent AI models at all spatial scales. Relative to the finest spatial scale, only results from the model with 0.5° × 0.5° resolution preserved enough distributional detail to reflect the known migration route for O. bartramii. Model results exhibited large variation dependent on spatial scale, particularly amongst CPUEAI scenarios. We suggest that scale comparisons among potential proxies should be conducted prior to AIs being used for applications such as population trends in stock assessment.

The differences of muscle proteins between neon flying squid (Ommastrephes bartramii) and jumbo squid (Dosidicus gigas) mantles via physicochemical and proteomic analyses

Neon flying squid (OB) and jumbo squid (DG) mantles were evaluated to reveal the similarities and differences in their physicochemical features and protein abundances. Microstructural results indicated that the OB mantle exhibited numerous myofibril fragments and disordered microstructures after frozen storage compared with DG tissues. Chemical analysis suggested that freezing resulted in a rapid decrease in myofibrillar protein (MP) content, Ca2+-ATPase activity, and total sulfhydryl content, and promoted the increase in carbonyl content of MPs in both OB and DG. While, DG presented better MP stability than OB muscle after 120 days of frozen storage. Label-free proteomic analysis detected 24 down- and 33 up-regulated differentially abundant proteins (DAPs) in OB and DG mantles. Identified DAPs including isocitrate dehydrogenase and malic enzyme initiated a rapid decrease in the MP properties in OB samples. Moreover, DAPs were related to cytoskeleton function, including paramyosin, tropomyosin, and troponin C, which improved the stability of DG in response to freezing-induced changes.

Factors affecting mercury concentrations in two oceanic cephalopods of commercial interest from the southern Caribbean

Mercury (Hg) concentrations have significantly increased in oceans during the last century. This element accumulates in marine fauna and can reach toxic levels. Seafood consumption is the main pathway of methylmercury (MeHg) toxicity in humans. Here, we analyzed total Hg (T-Hg) concentrations in two oceanic squid species (Ommastrephes bartramii and Thysanoteuthis rhombus) of an increasing commercial interest off Martinique, French West Indies. Stable isotope ratios reveal a negative linear relationship between δ15N or δ13C in diamondback squid samples. No significant trend was observed between δ34S values and T-Hg concentrations, contrasting with the sulfate availability and sulfide abundance hypotheses. This adds to a growing body of evidence suggesting Hg methylation via sulfate-reducing bacteria is not the main mechanism driving Hg bioavailability in mesopelagic organisms. All squid samples present T-Hg levels below the maximum safe consumption limit (0.5 ppm), deeming the establishment of a commercial squid fishery in the region safe for human consumption.

Interannual variability of body size and beak morphology of the squid Ommastrephes bartramii in the North Pacific Ocean in the context of climate change

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.

Synchronous Variations in Abundance and Distribution of Ommastrephes bartramii and Dosidicus gigas in the Pacific Ocean

An analysis was performed in this study to investigate synchronous fluctuations in abundance and distribution of Ommastrephes bartramii in the Northwest Pacific Ocean and Dosidicus gigas in the Southeast Pacific Ocean. The impacts of two Nino indices and regional water surface temperature on the two squids during 2006–2015 were evaluated, which possibly can explain the observed synchronicity. Catch per unit effort (CPUE) and the latitudinal gravity centers (LATG) of fishing effort were used to indicate squid abundance and distribution, respectively. The results indicated that both the CPUE and LATG showed highly interannual variations and synchronous fluctuation with significant negative associations between the two squid species from September to November. Strong positive cross-correlations with 2-month lag was found between sea surface temperature (SST) anomaly in the Nino 3.4 and Nino 1+2 regions, which have significant linkage with the SST on the fishing ground of O. bartramii and D. gigas, respectively. Moreover, the proportion of favorable-SST area (PFSST) and the latitudinal location of the optimal SST for O. bartramii and D. gigas were positively correlated with the CPUE and LATG, respectively. Increased O. bartramii PFSST clearly corresponded to decreased D. gigas PFSST in phase as well as the latitudinal location of the optimal SST from September to November over 2006–2015. Our findings suggest that synchronous changes in abundance and distribution of the two squids were due to simultaneous variations in the PFSST and the latitudinal location of the optimal SST front which were affected by the SSTA changes in the Nino 3.4 and Nino 1+2 regions.

Heterogeneity of mantle length-body mass relationship in different Ommastrephes bartramii populations based on linear mixed model

Heterogeneity of mantle length-body mass relationship in different Ommastrephes bartramii populations based on linear mixed model

Trans-Pacific multidecadal changes of habitat patterns of two squid species

Trans-Pacific changes in the habitat patterns of neon flying squid (Ommastrephes bartramii) in the Northwest Pacific Ocean and jumbo flying squid (Dosidicus gigas) in the Southeast Pacific Ocean during 1950–2015 were examined on a decadal scale using a habitat suitability index (HSI) model. The HSI model involved two environmental drivers for the occurrence of O. bartramii and D. gigas: sea surface temperature (SST) and sea surface height anomaly (SSHA). Significant seesaw-like patterns of environmental variability and habitat changes, consistent with the regime shift of positive and negative Pacific Decadal Oscillation (PDO), were observed for the two squid species. In a negative PDO phase, SST anomaly and SSHA increased on the fishing grounds of O. bartramii. The areas of suitable habitat of O. bartramii contracted markedly due to the decrease in suitable SST and SSHA. In contrast, cooling SST and decreasing SSHA on the fishing grounds of D. gigas during a negative PDO phase led to the formation of more suitable SST and SSHA, yielding expansive suitable habitats for D. gigas. Moreover, the most favorable SST for O. bartramii and D. gigas moved northward in the negative PDO regime, and the suitable habitat for both squids shifted into the northern regions as well. When the climate regime shifted into a positive PDO phase, the responses of the two squids were opposite to those in the negative PDO phase. Our findings indicate that interannual-to-decadal variability in habitat patterns of O. bartramii and D. gigas can be detected from climate regime shifts in the Pacific Ocean.

Ecological implications of unprecedented warm water anomalies on interannual prey preferences and foraging areas of Guadalupe fur seals

AbstractThe Guadalupe fur seal (GFS) currently is recovering from near extinction and prey availability is an important factor. Scat and stable isotope analyses (SIA) were used to assess GFS foraging on Guadalupe Island during 2013–2016. This period was characterized by normal (2013) ocean temperatures followed by warm conditions (2014–2016). Scat samples (~40/year) were collected for prey identification. Additionally, lanugo samples from 1‐month‐old pups (50/year) were processed for SIA (δ13C/δ15N). Interannual prey preferences were identified (ANOSIM,p &lt; .05), including significant differences between 2013 and the anomalous years. The most important prey species among these years was the jumbo squid; followed by the neon flying squid (2014–2016). The GFS diet was more specialized in 2013–2015 and more generalized in 2016. Prey from higher trophic levels (determined by scat analysis) were consumed during 2014–2016, but with significantly lower δ13C/δ15N values than in 2013 (ANOVA,p &lt; .05 for both isotope ratios). This pattern may indicate more northerly or offshore foraging areas, with the presence of oceanic prey (neon flying squid). The widest isotopic niche was observed in 2015 (2.2‰2), reflecting a broader foraging area. Our findings are an important step toward better understanding the impacts of climate change on the recovery of GFS.

Diet composition and feeding habits of the pelagic thresher shark Alopias pelagicus in Eastern Central Pacific Ocean, Ecuadorian waters

AbstractThe diet and feeding habits of the pelagic thresher shark Alopias pelagicus were analysed based on 104 stomachs (N = 84 females, 20 males) collected off Santa Rosa de Salinas, in the Ecuadorian Pacific. The sharks were caught between February 2008 and January 2009 in artisanal fisheries. The trophic spectrum of A. pelagicus included 19 prey items (10 cephalopods and 9 teleost fishes), the main four prey were the red flying squid Ommastrephes bartramii, jumbo squid Dosidicus gigas, the purpleback flying squid Sthenoteuthis oualaniensis and the South Pacific hake Merluccius gayi. The trophic niche was narrow (Bi = 0.2), thus the pelagic thresher could be considered a specialist predator. The analysis of dietary overlap showed high similarity between the diets of females and males (Cλ = 0.99), immature and mature females (Cλ = 0.81), immature and mature males (Cλ = 0.72), sizes of 141–230 cm TL and 231–321 cm TL (Cλ = 0.97), as well as sharks in rainy season and dry season (Cλ = 0.77). Using canonical of correspondence analysis (CCA), we found similarities in the diet for all categories recorded (sex: canonical r = 0.38, P = 0.97; sexual maturity stage: canonical r = 0.54, P = 0.31; sizes: canonical r = 0.55, P = 0.26; seasons of the year: canonical r = 0.61, P = 0.75). The trophic level estimated for A. pelagicus was 5.0, which is typical of top predators (quaternary consumers or tertiary carnivores).

Habitat suitability response to sea-level height changes: Implications for Ommastrephid squid conservation and management

Sea level rise, amplified by anthropogenic climate change, causes visible impacts on wildlife habitats in low-lying coastal areas. However, the potential consequences of sea level height (SLH) changes for pelagic fish habitats in the open oceans are poorly understood, especially for climate-sensitive Ommastrephid squid. In this study, the impacts of SLH changes were estimated under three different SLH change scenarios (5 cm, 20 cm, and 35 cm) for the western stock of winter-spring neon flying squid Ommastrephes bartramii, an ecologically- and commercially-important species in the northwest Pacific Ocean (NWPO). A habitat suitability index (HSI) modeling approach was applied to predict the habitat suitability of O. bartramii, using data from 2006 to 2014 for model construction and data from 2015 for model validation. Results showed that the decreasing catch-per-unit-effort (CPUE) of O. bartramii from 2006 to 2015 was highly correlated with the increases in sea level height (SLH). Significant positive relationships were found between the HSI values for latitudinal centers of gravity (LATGHSI) and SLH. The monthly-averaged HSI of O. bartramii was negatively correlated with the SLH, except in July and November. SLH scenarios revealed that the predicted suitable habitat (areas with HSI≥0.6) exhibited a decreasing trend with increasing SLH from August to October. In July and November, the suitable habitat initially increased in the +5 cm and +20 cm scenarios, but largely declined under the +35 cm scenario. The poor habitat (areas with HSI≤0.2) significantly increased under all SLH scenarios. A poleward shift of LATGHSI was observed under all scenarios. These findings suggest that the O. bartramii habitats in the NWPO are at risk to SLH changes and have important implications for better conservation and fishery management regarding pelagic short-lived Ommastrephid squid in global oceans.

Top predator reveals the stability of prey community in the western subarctic Pacific.

The stability of the ecosystems depends on the dynamics of the prey community, but changes in the composition and abundance of prey species are poorly understood, especially in open ocean ecosystems. We used neon flying squid Ommastrephes bartramii, an active top predator, as a biological sampler to investigate the dynamics of the prey community in the southwestern part of the Western Subarctic Gyre in the northwestern Pacific Ocean. Squid were collected monthly from July to November 2016. There were no significant differences among months in stable isotopes (δ13C and δ15N) in the digestive gland, a fast turnover organ reflecting recent dietary information. Similar findings were obtained from analyses of isotopic niche width and fatty acid profiles. The potential influence of the environment (monthly mean sea surface temperature, SST, and chlorophyll-a, Chl-a) on the prey community was examined with SST and Chl-a both varying significantly among sampling months. We found little evidence for significant effects of SST and Chl-a on the isotopic values, nor on the fatty acid profiles except for 20:4n6 and 24:1n9. These lines of evidence indicate that the prey community in the southwestern part of the gyre remains stable, with little evidence for systematic changes at the community level. This study provides a novel understanding of the dynamics of the prey community and highlights the use of top predators to study the trophic dynamics of an oceanic system where a long-term scientific survey is unavailable.

Stable isotope patterns of mesopelagic communities over two shallow seamounts of the south-western Indian Ocean

The stable carbon (δ13C) and nitrogen (δ15N) isotope values of soft tissues of micronekton (crustaceans, squid, mesopelagic fish) and zooplankton were measured from organisms collected on the RV Antea at two seamounts located in the south-western Indian Ocean: La Pérouse (summit depth ~60 m) and “MAD-Ridge” (thus named in this study; summit depth ~240 m). Surface particulate organic matter (POM-Surf) showed higher δ13C at the more productive MAD-Ridge than at the oligotrophic La Pérouse seamount. Particulate organic matter and zooplankton were depleted in 15N at La Pérouse pinnacle compared with MAD-Ridge. Gelatinous organisms and crustaceans occupied the lowest and intermediate trophic levels (TL ~2 and 3 respectively) at both seamounts. Mesopelagic fish and smaller-sized squid sampled at both seamounts occupied TL ~3 to 4, whereas the large nektonic squid, Ommastrephes bartramii, collected at MAD-Ridge only, exhibited a TL of ~5. The δ15N values of common open-water mesopelagic taxa were strongly influenced by specimen size and feeding habits at both seamounts, with an increase in δ15N values with increasing size. Carnivorous fish species sampled exclusively over the seamounts’ flanks and summits exhibited TL values of ~4, irrespective of their wide size ranges. The work could not demonstrate any differences in δ13C values of mesopelagic fish between the seamounts and the surrounding oceanic areas. The study segregated clusters of mesopelagic organisms according to their δ13C and δ15N values, with variations in stable isotope values reflecting a complex range of processes possibly linked to productivity as well as biological and ecological traits of the species (size and feeding mode).

The hepatoprotective effects of squid gonad phospholipids on fatty liver disease in zebrafish

Marine food processing by-products are a valuable source of marine phospholipids with different bioactivities. In a previous study, a method for the extraction of squid phospholipids (SPL) from female squid (Ommastrephes bartrami) gonads was developed. The purpose of this study was to investigate the protective effects of SPL on alcoholic and non-alcoholic fatty liver diseases. The Tg (L-FABP:EGFP) transgenic zebrafish line that expressed increased green fluorescent protein in the liver was used to measure liver injury using phenotype analysis. Lipids accumulation in the liver was observed using oil red O staining. Real-time PCR was done to measure gene expression. The results showed that SPL decreased lipids accumulation, restored liver phenotype, relieved loose cell-to-cell contact, and decreased large vacuoles in the liver. The hepatoprotective mechanism was associated with increased lipids uptake, transport, and metabolism.