Dosidicus Research Articles

An Automatic Data-Driven Long-term Rainfall Prediction using Humboldt Squid Optimized Convolutional Residual Attentive Gated Circulation Model in India

<p style="text-align:justify;"><span style="font-family:"Times New Roman","serif";font-size:12pt;line-height:200%;">Precise long-term rainfall forecasting is becoming progressively significant, predominantly in periods of fluctuating weather circumstances. These prophecies are indispensable for several areas, including agronomy, water resource supervision, flood attentiveness, and effluence monitoring. This framework investigates the composite association between climatological data, with an emphasis on the precise estimating of rainfall by finding the effect of temperature disparities on rainfall outlines in diverse states of India. The developed framework undergoes two phases: pre-processing and rainfall forecasting. At first, the Improved min-max normalization (I-MMN) technique is highlighted in the preprocessing stage to eliminate unsolicited missing values from the database. Then, the convolutional residual attentive gated circulation unit (CResAtt-GCU) technique is presented to envisage the amount of rainfall that occurs in various Indian states. Finally, the Humboldt squid optimizer (HBSO) technique is presented to tune the parameters of the developed model to minimize network complications during the training process. The developed framework is processed under the Python platform and the real-time rainfall prediction database collected between 2000-2023 is utilized for the experimentation process. Various computational measures like R2, root mean square error (RMSE), Kling-Gupta Efficiency (KGE), Nash-Sutcliffe Efficiency (NSE), mean absolute error (MAE), and computation time are evaluated and distinguished from different studies. The overall R2 of 0.993, RMSE of 0.84, KGE of 0.96, NSE of 0.992, MAE of 0.53, and overall CT of 86.66s are obtained by the developed technique against various conventional studies on forecasting the rainfall in different regions of India.</span></p>

The departure of sperm whales (Physeter macrocephalus) in response to the declining jumbo squid (Dosidicus gigas) population in the central portion of the Gulf of California.

As sperm whales are important predators that control energy flux in the oceans, changes in their population can be used as a sentinel to measure of ecosystem health. The present study conducted a sperm whale survey of the eastern Midriff Islands Region in the Gulf of California over the course of nine years, recording sightings and collecting photographs of the fluke of sperm whale individuals. A photo-identification catalog was compiled, while individual recapture data were used to estimate the population size in the central portion of the Gulf of California, using a Jolly-Seber POPAN open population model. The results obtained show a yearly population of between 20 and 167 sperm whales, with a super population of 354 sperm whales observed between 2009 and 2015. However, from 2016 to 2018, no sightings of the species were recorded, which coincides with the decline observed in landings of their main prey, the jumbo squid, in the region. General additive model conducted on sperm whale sightings per unit of effort vs jumbo squid landings obtained an adjusted R2 of 0.644 and a deviance explained of 60.3%, indicating a good non-linear relationship between sightings of this odontocete and its prey availability. This evidence suggests that sperm whales departed the region between 2016 and 2018, due to a documented fishery collapse alongside changes of their main prey into its small phenotype, possibly as the result of increase warming conditions in surface and subsurface waters in the Gulf of California in the last three decades.

Chitosan extracted from the feather of Dosidicus gigas crosslinked with glutaraldehyde for use as a 99Mo adsorbent

The production of Technetium-99 m (99mTc) is important for cancer diagnosis. The solvent extraction is the most widely used method to obtain 99mTc; however, due to the evaporation of the polluting solvent into the environment, a radiochemical separation using a chromatographic column system based on adsorbent materials would be cleaner and more efficient.In this study, squid feather (Dosidicus gigas) chitosan (SFC) polymers have been synthesized and crosslinked with glutaraldehyde solutions at concentrations of 50, 40 and 25 % to study the adsorption of 99Mo with the aim of test a promising material to produce 99mTc in the chromatographic column of the 99Mo/99mTc generator. Likewise, the same methodology of synthesis was performed using a commercial chitosan (CC) as a control. Deacetylation degree was measured obtaining 74.15 % and 77.65 % for the SFC and CC polymers, respectively. The molecular weight obtained was 990.72 kDa for SFC and 722.72 kDa for CC and the characterization of the biopolymers was performed with FTIR, SEM, XRD, TGA y FT Raman techniques. Equilibrium time, adsorbent mass and pH effect were evaluated as factors that influence the adsorption process of 99MoO4-2. The zero load point (pHPZC) analysis confirmed the positive charge of the crosslinked polymers, improving the adsorption capacity of 99MoO4-2 at low pH values between 2 and 4, following a pseudo-first order model. With respect to the adsorption isotherms, they exhibit maximum values of 99MoO42- of 482 mg g−1 SFCG40 and 502 mg g−1 CCG25 with a better fit to the Langmuir theoretical model.

Carboxymethyl chitosan-assisted formation of stable soy protein isolate emulsions and their impact on the properties of squid (Dosidicus gigas) surimi gel

In this study, emulsions co-stabilized by soy protein isolate (SPI) and carboxymethyl chitosan (CMCS) were prepared and the effects of different SPI/CMCS ratios (1:0, 4:1, 2:1, 1:1, 1:2, 1:4) on the emulsification characteristics, rheological properties, and microstructure of the composite emulsions were investigated. Subsequently, the effect of these emulsions on the gel properties of squid (Dosidicus gigas) surimi was evaluated. The results indicated that the particle size, interfacial tension and creaming index decreased with increasing CMCS ratio, while the percentage of interfacial protein adsorption increased. The particle size and interfacial tension reached a minimum value, and the interfacial protein adsorption peaked at the optimal SPI/CMCS ratio (1:2, w/w). Additionally, CMCS altered the secondary structure of the protein when complexed with SPI, resulting in a more ordered internal structure. Upon adding an appropriate amount of CMCS-proportioned composite emulsion to the surimi gel, significant improvements were observed in hardness, gel strength, whiteness, immobilized water and decreased drip loss and free water. However, over-addition of CMCS resulted in the quality deterioration of surimi gel. Single SPI emulsions had minimal effects on the surimi gel, indicating the superiority of composite emulsions. In conclusion, the SPI/CMCS composite emulsions enhanced the gel properties of surimi gel, offering new avenues to enhance the quality of emulsified surimi-based products.

Tenderization of giant squid (Dosidicus gigas) meat pretreated with pulsed electric field and Asian seabass trypsin with the aid of vacuum impregnation

Giant squid (Dosidicus gigas) meat (GSM) generally has a tough texture, significantly lowering its acceptability by consumers. To enhance tenderness, GSM was pretreated with pulsed electric field (PEF) at 250 V for 5 min (PEF-GSM). Thereafter, PEF-GSM was soaked in partially purified trypsin (PPT) from pyloric caeca of Asian seabass obtained from ammonium sulfate precipitation (40%–60% saturation). The soaking was done at various concentrations of PPT (0, 5, 10 and 20 units/mL) with the aid of vacuum impregnation (VI) (2 cycles). Subsequently, PPT-soaked GSM samples were incubated at 60 °C for 5 and 10 min, followed by cooking at 100 °C for 2 min. For quality assessment, untreated cooked GSM (CON-GSM) was also prepared. Lightness of PEF-GSM samples increased (p < 0.05), compared to that of CON-GSM. After hydrolysis with PPT, myofibrillar proteins were degraded with coincidental upsurge in AAGC (α-amino group content). Protein degradation and AAGC became more pronounced with increasing PPT concentration and incubation time. PEF-GSM treated with PPT at 20 units/mL (PEF-GSM-20) and incubated for 10 min had the decreased firmness and toughness values, however its cooking loss slightly increased. Degradation of myofibrillar proteins was reconfirmed by FTIR spectra and microstructure alteration. PEF-GSM-20 with incubation at 60 °C for 10 min showed higher overall likeness score (p < 0.05), indicating a significant improvement in acceptability of consumers. Thus, combined application of PEF, PPT (20 units/mL) and VI before incubation at 60 °C for 10 min significantly enhanced the eating quality of GSM, making it more preferable for consumers.

Cryoprotective effect of low molecular-mass nitrogen compounds on the myofibrillar protein of the jumbo squid (Dosidicus gigas) muscle

The study aimed to evaluate the low molecular-mass nitrogen compounds (LMMNC) arginine (Arg), taurine (Tau), and trimethylamine oxide (TMAO) (individually or their mixtures) cryostabilizing effect over jumbo squid (Dosidicus gigas) myofibrillar protein (JSMP) frozen at -20°C for 0, 30, and 90 days. Washed muscle (three times, 1:3, muscle:water) was lyophilized (sample). Washing water was ultrafiltrated (&lt;1 kDa cut-off) and permeate lyophilized (&lt;1 kDa fraction). LMMNC, Control+ (with &lt;1 kDa fraction)] added at muscle concentration and control (washed-muscle only) were stored at -20 °C. Cryoprotective effect on JSMP was evaluated by differential scanning calorimetry, surface hydrophobicity (SoANS), solubility, and total-sulfhydryl (TS) content. Myosin thermal stability increased (P ≤ 0.05) in Control+ (43.6 ± 0.1), TMAO (44.3 ± 0.3), and Arg + TMAO (44.2 ± 0.9) compared to Con (42.6 ± 0.3) before freezing (day 0). At 90 days of storage, all TMAO-involved treatments and Control+ remained higher (p ≤ 0.05) than Control. Solubility increased (p ≤ 0.05) in Tau (11.2±0.0-12.8±0.1) and Arg+Tau (10.6±0.1-12.7±0.0) comparing day 0 vs. 90, respectively. LMMNC reduced SoANS (p ≤ 0.05, Arg+Tau+TMAO) throughout storage. LMMNC reduced (p &gt; 0.05) TS in most treatments. LMMNC, especially Taurine and TMAO, protects JSMP from freezing denaturation, stabilizing its structure.

Spatial Distribution and Abundance of a Pelagic Squid during the Evolution of Eddies in the Southeast Pacific Ocean

The Humboldt squid (Dosidicus gigas), is a significant economic species off Peru. The abundance and distribution of the species are highly susceptible to fluctuations in marine environmental conditions. The evolution of mesoscale eddies represents one of the dynamic processes in the ocean, exerting varying degrees of influence on regional biogeochemical processes from generation to dissipation. However, the mechanisms governing the regulation of abundance and spatial distribution of D. gigas off Peru during this evolution remain unclear. Therefore, this study employed normalization techniques and the habitat suitability index (HSI) model, utilizing data from the D. gigas fishery, mesoscale eddies, and marine environmental factors (including sea surface temperature, temperature at 50 m depth, and chlorophyll-a concentration) to analyze the environmental changes and the abundance, spatial distribution, and habitat changes of D. gigas during the evolution of mesoscale eddies. The results indicate that eddies undergo four stages: formation, intensification, maturity, and decay. During eddy evolution, the abundance of D. gigas exhibited an initial increase and a subsequent decrease within cyclonic eddies (CEs), whereas, within anticyclonic eddies (AEs), abundance showed a gradual decline. The outcome of the HSI model revealed that, the habitat suitability and the proportion of suitable habitat areas within eddies were highly consistent with the abundance of D. gigas during all stages of the eddies other than the intensification stage of AEs. The study speculated that both CEs and AEs can create favorable environmental conditions during the maturity stage, thereby leading to an increase in suitable habitat and abundance of D. gigas. These findings emphasize the significant impact of mesoscale eddy evolution on the abundance and habitat distribution of D. gigas.

Feeding ontogeny and trophic ecology of the shortfin mako shark, Isurus oxyrinchus, on the west coast of Baja California Sur, Mexico

Certain shark species are considered top predators, which bestows them with important roles in the trophic dynamics of marine ecosystems. The present study describes the ecology and ontogeny feeding of the shortfin mako shark Isurus oxyrinchus along Baja California Sur, Mexico, through stomach content analysis (SCA) and stable isotope analysis (SIA). A total of 272 stomachs and 39 muscle samples of I. oxyrinchus were analyzed. The SCA indicated that I. oxyrinchus has a wide trophic spectrum, with a consumption preference for Dosidicus gigas, Prionotus albirostris, and Scomber japonicus; however, feeding differences by sexes and sexual maturity stages were evidenced. The SCA indicated that I. oxyrinchus is a specialist consumer (Bi = 0.10) occupying high trophic positions (TP: 4.7–5.2). SIA reflected isotopic signals between –17.3 ‰ and –15.7 ‰ for δ13C and 15.5 ‰ and 19.5 ‰ for δ15N, but with some differences by maturity stages in δ15N (Young-of-the-year = 16.4 ± 0.66 ‰, Juveniles = 18.1 ± 0.13 ‰, adults = 18.3 ± 0.56 ‰). The SIA suggests that this species has a wide isotopic niche (SEAC: 1.08 ‰2) and occupies high TP (3.9–6.2). In conclusion, I. oxyrinchus presents segregation by sex and maturity stages, shows ontogenetic changes in habitat use and prey selection related to the physical characteristics of the zone (bathymetry), and plays important roles in the trophic dynamics of marine ecosystems.

Lipidomics profile and volatile compounds of squids (Illex argentinus, Ommastrephes Bartram and Dosidicus gigas) in the Argentine, North Pacific Ocean, Equator and Peru by UPLC-triple TOF-MS and HS-SPME-GC-O-MS

Comprehensive lipid and volatile compound analyses were performed with squids collected from four varied geographical locations to discriminate the regional characteristics. A total of 1442 lipid molecules and 110 volatiles were detected in the squid muscle samples. There were significant differences in the lipid profiles between Argentine squid (Illex argentinus, AGT), North Pacific Ocean squid (Ommastrephes Bartram, NPO), Equatorial squid (Dosidicus gigas, EQ), and Peruvian squid (Dosidicus gigas, PR) muscle. Phosphatidylcholines (14.64%), triacylglycerols (12.42%), and ceramides (10.97%) were the main lipid components. The contents of polyunsaturated fatty acid in phospholipids and in glycerolipids were 30.35–52.05% and 18.11–25.15%, respectively. The volatiles in squids exhibited significant regional variation; 1-pentanol and 1-octanol, 2-ethyl-1-hexanol and terpinen-4-ol, 2,7-ethyl-1-hexanol, 3-methy-1-butanol and 2-propyl-1-pentanol were identified as characteristic flavor compounds in AGT, NPO, EQ, and PR, respectively. Sphingomyelin, phosphatidylserine, phosphatidylethanolamine, and ceramide were strongly correlated with volatiles in squid muscle. Our study is a reference for the lipid nutritional value and flavor compounds of squids.

RETRACTED: Anohova et al. The Dosidicus gigas Collagen for Scaffold Preparation and Cell Cultivation: Mechanical and Physicochemical Properties, Morphology, Composition and Cell Viability. Polymers 2023, 15, 1220.

The Polymers Editorial Office retracts the article, "The Dosidicus gigas Collagen for Scaffold Preparation and Cell Cultivation: Mechanical and Physicochemical Properties, Morphology, Composition and Cell Viability" [...].

Elevating labor concerns in small-scale fisheries: challenges to decent work in Peru’s jumbo flying squid fishery

Despite growing attention on severe labor abuses in seafood production, questions remain about the broader range of challenges to decent work in the sector. Small-scale fisheries (SSFs) in particular have received relatively little attention from a labor-focused perspective. Motivated by this gap, this study elaborates a methodology to assess working conditions in SSFs across multiple dimensions of decent work, specifically through a case study of the artisanal jumbo squid fishery in Peru, a socially and economically important fishery in which working conditions are poorly understood. The findings highlight key decent work deficits in this fishery, including: inadequate coverage and lack of social protections; remuneration occasionally below the minimum wage; excessive working hours; increasingly longer trips in vessels that often lack adequate occupational safety and health features; informal employment relations and high turnover of crew, which are linked to safety issues (i.e., crew sometimes lack skills for this difficult work at sea); and fragmented fishing organizations with limited capacities for social dialogue. Many of the problems are rooted in or exacerbated by the broader governance context, especially widespread informality. The primary policy solutions being pursued are not labor-specific and are unlikely to address decent work deficits. Addressing these complex problems will require involving fishers—importantly, crew members—in efforts to drive improvements in the fishery and enhancing their capacities to lead in the development of solutions to the problems that affect them. More work is necessary to refine indicators and assess working conditions, but this work contributes towards advancing methodologies and highlighting the importance of studying labor in SSFs.

Changing Humboldt Squid Abundance and Distribution at Different Stages of Oceanic Mesoscale Eddies

Humboldt squid, Dosidicus gigas, is one of the main economic cephalopod species off Peruvian waters, and their abundance and distribution are regulated by localized oceanic mesoscale dynamical processes. To this end, the present study employs normalization and frequency distribution methods, combining mesoscale eddy, oceanic environment, and D. gigas fishery data. This is the first exploration into the different stages of mesoscale eddies during their evolution off Peruvian waters and their influence on the regional marine environment, as well as the abundance and distribution of D. gigas resources. The results indicate that across the four stages of eddies, namely formation, intensification, mature, and aged, their kinetic energy and structure follow a pattern of “growth–equilibration–decay”. The abundance of D. gigas within the eddy’s covered zone undergoes an initial increase, followed by a decrease during the evolution of the four stages, peaking during the eddy’s mature stage. The abundance of D. gigas was higher in the anticyclonic eddies than that in the cyclonic eddies under different stages. The environmental factors conducive to D. gigas in eddies exhibited similar changes to D. gigas abundance throughout the eddy’s different stages. Our research emphasizes that anticyclonic eddies, during their evolution, exerted a more significant impact on the abundance and distribution of D. gigas in the Peruvian waters compared with cyclonic eddies. The eddy-induced changes in water temperature and productivity caused by the eddies may be the primary drivers of this impact.

Mitochondrial DNA diversity of sperm whales (Physeter macrocephalus) in the Gulf of California under a changing environment

The mitochondrial diversity of the sperm whale in the Gulf of California (GC) from 2004 to 2017 was analyzed using the control region from 95 samples and compared with two preceding studies. This study examined the relationship between the mitochondrial genetic diversity of sperm whales, and the abundance of jumbo squid (Dosidicus gigas) in the GC, as indicated by squid catches. Furthermore, the influence of climate regimes on this relationship was also assessed. Of the total 16 haplotypes registered for the GC, eight haplotypes, representing 50%, were identified in this study. One of these haplotypes was only recorded in the Atlantic Ocean, and another is newly documented. Haplotype diversity (h = 0.640 ± 0.051) and nucleotide diversity (π = 0.00158 ± 0.00019) showed lower values than those previously reported for the GC. The genetic differentiation index among three periods analyzed was significant (Fst = 0.27, p < 0.01), with a greater variability observed within periods (72.19%) compared to between periods (27.81%). This suggests either a differential influx of haplotypes or a preference of matrilines for specific areas within the GC. The sex ratio of 3.5:1 females to males was consistent with previously reported data for the GC and other regions. A temporal decrease in the number of haplotypes in the GC coincided with an increase in Sea Surface Temperature (SST), a decrease in chlorophyll values (Chl-a), and a reduction of giant squid catches. These trends suggest that shifts in the GC climate regime could exert selective pressure, favoring certain matrilineal lineages.

The value chain of the jumbo squid (Dosidicus gigas) in Mexico: Diagnostic, structural analysis, and scenarios

The value chain for jumbo squid fishery encompasses a process of linking multiple components and actors that generate and promote capitalization of the added value of this fishery product. This study aims to diagnose the value chain for jumbo squid in Mexico using the structural analysis approach, allowing a description of the main actors, and their interactions with the markets, socioeconomic drivers, as well as the influence of different variables in the performance of jumbo squid chain value. The results derived from the structural analysis, six variables (related to the transformation, marketing, and consumption activities) and two actors (producers and academic research) were identified as the most relevant. The competitive advantages and added value could be reached by integrating the aspects related to the most relevant variables and taking appropriate decisions to deal with situations of uncertainty, which can promote weak nodes in the value chain, primarily because of the failures in the commercialization and consumption of jumbo squid. This suggests that efforts should not be concentrated on a single node but should be addressed jointly. Considering that the jumbo squid value chain currently depends on the changing conditions of the fishery, which is marked by production instability, causing uncertainty in the subsequent nodes; the status indicates that a restructuring of the value chain is evident since the market is prone to dismantling or self-regulation over the medium term.

Biological and Fishery Parameters of Jumbo Squid (Dosidicus gigas) in the Colombian Pacific, a Resource without Directed Fishing Exploitation

The distribution range of the jumbo squid (Dosidicus gigas) has increased over the past few decades; it is now found in the entire Eastern Pacific Ocean and is considered an important species in the small and large fisheries of Chile, Perú, Ecuador, Costa Rica and Mexico but not in the Pacific region of Colombia. Three night-fishing campaigns were conducted over a year in the coastal Baudó-San Juan environmental unit, adjacent to the Bajo Baudó Encanto de Manglares Regional Integrated Management District in Chocó, at three locations 20 km, 35 km, and 45 km from the coastline to establish the availability and viability of jumbo squid as an alternative to the target species of artisanal fisheries in the Colombian Pacific. Night fishing sets were conducted at 60 m and 200 m depth at each sampling station to assess some of the biological parameters of the jumbo squid population (mantle length-ML, weight, growth and size at sexual maturity). Most catches were obtained in February and March. Growth was isometric, the average catch size was 24.3 cm ML, size at sexual maturity (L50) was 23.25 cm ML, estimated maximum size (L∞) was 39.9 cm ML, the growth constant (K) was 0.83, and mortality due to experimental fishing was 26 cm ML. According to our results, the jumbo squid fishery in the Colombian Pacific artisanal fishery would be viable during the first months of the year.

Jumbo Flying Squid Distribution within Anticyclonic Eddies under Anomalous Climatic Conditions

Anticyclonic eddies are widely distributed off Peru, producing obvious effects on climate-environment-sensitive jumbo flying squid Dosidicus gigas . However, how the habitat of D. gigas changes within anticyclonic eddies during El Niño events is still unknown. Therefore, this study constructed a habitat model with different weights and screened the optimal performance model using fishery data from September to December during 2015 to 2019, as well as vertical water temperature data (sea surface temperature and 50 m water depth temperature) and surface chlorophyll concentration data (Chl-a). Then, combined with the eddy tracking dataset, the differences in the variation of resource abundance and habitat of D. gigas within the anticyclonic eddy between the 2015 El Niño year and the 2019 normal year were further comparatively analyzed based on the optimal habitat model. Compared with the normal year of 2019, the 2015 El Niño event occurred with a lower intensity of eddy activity, and both temperature in the fishing ground and near-surface sea water temperature within the anticyclonic eddy became warmer, with a small decrease in Chl-a; the percentage of suitable near-surface water temperature within the anticyclonic eddies decreased significantly, and suitable Chl-a decreased slightly; the suitable habitat for D. gigas was reduced dramatically, which was unfavorable to D. gigas survival. Our finding suggested that that anomalous climatic events can have an impact on eddy strength, as well as on the suitable environment and habitat within the anticyclonic eddies, resulting in variations in the abundance of D. gigas .

Effect of different pretreatments on the hydrolysis efficiency and flavor of squid viscera (Dosidicus gigas)

In order to better utilize the proteins in squid viscera (Dosidicus gigas), the effects of different pretreatments on the degree of hydrolysis (DH) and volatile compounds of hydrolysates were studied. The DH was used as an indicator to select alkaline protease as the optimal protease from 8 types of proteases. The hydrolysis conditions of alkaline protease and the flavor of the hydrolysates were investigated through single-factor, response surface methodology, and pretreatment-assisted hydrolysis experiments. The results showed that alkaline protease had the highest DH (42.08 ± 0.58%), with enzyme dosage of 1.5%, hydrolysis temperature of 45 °C, hydrolysis time of 5 h, and liquid-solid ratio of 4:1. The DH of the ultrasound group was significantly higher than other groups, with the highest DH (45.67 ± 0.34%) after ultrasound for 40 min (U40). The proportion of molecular weight < 1 kDa and the content of free amino acids (1613.64 mg/100 g) were the highest at U40. The electronic nose results indicated that the composition of organic sulfur and aliphatic compounds in U40 showed significant differences compared to other products. The U40 sample had the highest type and content of volatile compounds (especially benzaldehyde), which was more conducive to the volatilization of flavor substances. In conclusion, U40 pretreatment can effectively improve the DH and flavor of hydrolysates.

Predicting the Fishery Ground of Jumbo Flying Squid (Dosidicus gigas) off Peru by Extracting Features of the Ocean Environment

We introduce a novel method that combines satellite data, advanced clustering techniques, machine learning feature extraction, and statistical models to enhance fishery forecasting accuracy. Focusing on jumbo flying squid in the southeast Pacific Ocean near Peru, we utilize MODIS-Aqua and MODIS-Terra satellite data on sea surface temperature (SST) to construct a deep convolutional embedded clustering (DCEC) model and extract the monthly SST features (FM) based on an optimized number of clusters determined by the Davies–Bouldi index (DBI). We use the extracted FM to construct a series of Generalized Additive Models (GAM) to forecast the catch per unit effort (CPUE) of jumbo flying squid within a spatial resolution of 0.5° × 0.5°. Our results demonstrate the following findings: (1) The SST feature clusters obtained through the DCEC model could capture the SST monthly variations; (2) The GAM models with FM outperform the models with the traditional monthly average SST in terms of predictive accuracy; (3) Using both FM and average SST together can further improve model performance. This study demonstrates the effectiveness of the DCEC combined with DBI in extracting marine environmental features and highlights the ocean environment feature extraction method to enhance the precision and reliability of fishery forecasting models.

PH-dependent interactions of coacervate-forming histidine-rich peptide with model lipid membranes

Peptide-based liquid droplets (coacervates) produced by spontaneous liquid-liquid phase separation (LLPS), have emerged as a promising class of drug delivery systems due to their high entrapping efficiency and the simplicity of their formulation. However, the detailed mechanisms governing their interaction with cell membranes and cellular uptake remain poorly understood. In this study, we investigated the interactions of peptide coacervates composed of HBpep—peptide derived from the histidine-rich beak proteins (HBPs) of the Humboldt squid—with model cellular membranes in the form of supported lipid bilayers (SLBs). We employed quartz crystal microbalance with dissipation monitoring (QCM-D), neutron reflectometry (NR) and atomistic molecular dynamics (MD) simulations to reveal the nature of these interactions in the absence of fluorescent labels or tags. HBpep forms small oligomers at pH 6 whereas it forms µm-sized coacervates at physiological pH. Our findings reveal that both HBpep oligomers and HBpep-coacervates adsorb onto SLBs at pH 6 and 7.4, respectively. At pH 6, when the peptide carries a net positive charge, HBpep oligomers insert into the SLB, facilitated by the peptide’s interactions with the charged lipids and cholesterol. Importantly, however, HBpep coacervate adsorption at physiological pH, when it is largely uncharged, is fully reversible, suggesting no significant lipid bilayer rearrangement. HBpep coacervates, previously identified as efficient drug delivery vehicles, do not interact with the lipid membrane in the same manner as traditional cationic drug delivery systems or cell-penetrating peptides. Based on our findings, HBpep coacervates at physiological pH cannot cross the cell membrane by a simple passive mechanism and are thus likely to adopt a non-canonical cell entry pathway.

Key species and indicators revealed by an uncertainty analysis of the marine ecosystem model OSMOSE

Systematic analyses that examine uncertainty in models are essential for assessing their credibility. In this study, we implemented an uncertainty analysis that quantifies the effect of parameter uncertainty on a set of ecological indicators in outputs of the marine ecosystem OSMOSE model applied to the northern Peru Current ecosystem (NPCE OSMOSE). We worked under simple uncertainty assumptions corresponding to ranges of 10, 20, and 30% variability around the reference values of the parameters describing the dynamics of the species modelled in NPCE OSMOSE. The results based on nearly 1.5 million simulations help to identify the main sources of uncertainty that could be of use to focus future research and point to the most reliable indicators in the face of uncertainty. First, uncertainty in the parameters of some species, in particular a key zooplankton species and Humboldt squid, have far-reaching impacts on the modelled biomass of other key species. Second, a set of ecological indicators appear to be relatively insensitive to input uncertainty and may therefore be useful in supporting ecosystem-based management. Furthermore, our findings underline the need for better species representation in terms of data quality but also bottom-up and top-down processes in trophic models. We highlight the difficulties of studying uncertainty in complex models while presenting an approach that can serve as a template for addressing uncertainty analysis in other ecosystem models. Finally, although this approach focuses on parameter uncertainty, it could also serve as a guide to address structural, initial conditions and model forcing uncertainties.