Competition For Food Research Articles

Trophic Structure and Isotopic Niche of Invaded Benthic Communities on Tropical Rocky Shores

When a species is introduced in a new location, it is common for it to establish itself when it finds favorable conditions in the receptor community with regard to interspecific interactions with native species. The azooxanthellate corals Tubastraea coccinea and Tubastraea tagusensis are invasive species introduced in the Caribbean Sea, the Gulf of Mexico, and the Brazilian Southwest Atlantic. They are successful competitors for space, have multiple reproductive modes, and have high larval dispersion and recruitment, but studies on food and trophic relationships of the genus Tubastraea are still scarce. In the present study, we used isotopic values of δ13C and δ15N to investigate trophic relationships in rocky shore communities invaded by T. tagusensis and T. coccinea corals under different oceanographic and anthropogenic contexts. Using metrics derived from the isotopic values, we show that invaded communities have a lower degree of trophic diversity, with species characterized by similar trophic ecologies while abiotic factors seem to contribute to the biotic resistance of communities exposed to invasion events. Tubastraea spp. occupy a niche space similar to that occupied by the native community of suspension feeders, sharing resources already consumed by the receptor community, which makes invading corals successful competitors for food.

Transcranial optogenetic brain modulator for precise bimodal neuromodulation in multiple brain regions

Transcranial brain stimulation is a promising technology for safe modulation of brain function without invasive procedures. Recent advances in transcranial optogenetic techniques with external light sources, using upconversion particles and highly sensitive opsins, have shown promise for precise neuromodulation with improved spatial resolution in deeper brain regions. However, these methods have not yet been used to selectively excite or inhibit specific neural populations in multiple brain regions. In this study, we created a wireless transcranial optogenetic brain modulator that combines highly sensitive opsins and upconversion particles and allows for precise bimodal neuromodulation of multiple brain regions without optical crosstalk. We demonstrate the feasibility of our approach in freely behaving mice. Furthermore, we demonstrate its usefulness in studies of complex behaviors and brain dysfunction by controlling extorting behavior in mice in food competition tests and alleviating the symptoms of Parkinson’s disease. Our approach has potential applications in the study of neural circuits and development of treatments for various brain disorders.

Increasing competition for water resources in the food and energy industries.

Exploring the mechanisms of competition for water resources in the regional food and energy industries,taking effective countermeasures in advance will help to promote the sustainable development of the regional food and energy industries. Based on the theory of water footprint, this paper quantifies the water footprint of grain and energy in Shanxi Province, China, and the competition index of energy-grain industry to water resources. Through the ratio of grain blue water and energy water footprint to total water consumption in the region, this study coupled the characteristics of their proportional changes to obtain a competition index that can characterize the competition relationship between regional food and energy industries for water resources. The results showed that (1) In 2000-2021, although the grain yield increased by 81.1%, the grain water footprint only increased by 11.2%, with an average annual growth of 1.0%. The proportion of blue, green and gray water footprints changed from 14.1%, 54.3% and 31.6% in 2000 to 18.8%, 41.2% and 39.9% in 2021, respectively. (2) The energy water footprint increased at an average annual rate of 10.8%, an increase of 544.7% over the period. The coal, natural gas and thermal water footprints in 2021 have increased by a factor of 2.7, 109.2 and 4.0, respectively, compared to 2000. Coal's share of the energy water footprint is 70.6%. (3) The average value of the food and energy industry's competition index for water resources is 0.77, increasing from 0.42 in 2000 to 0.94 in 2021, an average annual increase of 4.3%. These results show that the future sustainable development of the region is facing the major challenge. Therefore, from the perspective of reducing the demand for crop and energy water footprint, some suggestions are put forward to effectively promote the healthy development of the region.

Structural Challenges and a Role Innew Health Policy Management in Future India

Objectives: This paper aims to investigate the evolution of supply chain management (SCM) in the globalization era, which is typified by the focus on global supplier relationship systems and the growth of supply chains across national borders and continents. Methods: The introduction of the mathematical models, which include a broad range of linear, integer, and non-linear programming models, is the first section of this paper. Location modeling and transportation planning are two common applications for heuristic models. Although mathematical and heuristic models are best suited for analytical problem solving, complex real-world issues frequently call for basic assumptions. In simulation models, the intricacies of the problem and the relationships between different variables are represented by equations, and then an attempt is made to discuss a comparative analysis of the results. Results: Once put into place, the system always has a lifespan that is determined by the previously mentioned factors and problems. It would be more accurate to say that all developed systems should be reviewed on a regular basis and any necessary adjustments made to maintain their functionality and effectiveness. Conclusion: According to this paper, the fiercely competitive food production market is largely driven by time-based competition, and a producer's or farmer's ability to offer a customer a flexible and responsive supply determines its competitive edge. These businesses understand that providing creative products and outstanding customer service is essential to retaining clients and opening up new revenue streams.

Spatial overlap and trophic interactions between a native commercial crab and the European green crab in Atlantic Patagonia

The European green crab, Carcinus maenas, is a highly invasive species capable of exerting significant impacts on native biota, particularly on species of ecological and/or economic importance. In Atlantic Patagonia, green crabs have been rapidly expanding their distribution along the coast, yet their biotic interactions with native crab species have not been examined. Here, we investigate the agonistic interactions of invasive green crabs with the native commercially important paddle crab (Ovalipes trimaculatus) in Atlantic Patagonia. This study determined spatial overlap between both species and experimentally evaluated predator-prey interactions and competition for food. Our results indicate coexistence of Carcinus and Ovalipes trimaculatus in sandy bottoms of Nuevo Gulf, with green crabs being much more abundant than paddle crabs. Carcinus was present across all sampled locations, exhibiting highly variable abundances and considerable sex ratio disparity. In aquarium trials, mutual predation only occurred between Carcinus and O. trimaculatus of contrasting sizes, although the time taken to observe predation events significantly differed between both species, with green crabs displaying much higher voracity. Additionally, green crabs were the first to hoard food when it was offered. These findings suggest that predation by green crabs especially on juveniles paddle crabs may play a role in the decline of O. trimaculatus in formerly abundant shallow areas in Nuevo Gulf. Thus, this study lays the groundwork for assessing interactions between Carcinus and a broader range of native crab species, aiming to deepen our understanding of current and potential interactions in the SW Atlantic.

Competition and Facilitation Influence Central Place Foraging Ecology in a Colonial Marine Predator.

Coloniality is strongly shaped by aspects of social foraging behaviour. For example, colonies may be important sources of information, while food competition may increase foraging efforts and limit colony size. Understanding foraging ecology considering these apparent trade-offs is required to develop a better understanding of colonial living. We combined animal-borne GPS, cameras and dive recorders to study social foraging in breeding adult northern gannets Morus bassanus-a wide-ranging colonial seabird. We first tested for indirect evidence of prey depletion around the colony by estimating dive location, depth and duration. Next, we tested for sociality during different behaviours (commuting, foraging and resting) and distance from the colony. Finally, we quantified flocks of inbound and outbound birds to compare social foraging between outbound and inbound legs of the commute. Dive probability and depth (n = 46 individuals; n = 1590 dives) increased with distance from the colony, creating dive clusters at ~100 and 180 km consistent with conspecific prey depletion. Camera stills (n = 8 individuals; n = 7495 images) show gannets are highly social, but this varied among behaviours. Sociality was highest during foraging and commuting; especially inbound and social foraging was more likely far from the colony. Gannets were equally likely to be solitary or social when leaving the colony but returning birds were more likely in larger flocks. In summary, despite experiencing intraspecific competition for food, gannets engage in dynamic, context-dependent social foraging associations. Conspecifics aggregated far from the colony possibly because of a prey depletion halo closer to home, but this provided potential benefits via local enhancement and by returning to the colony in flocks. Our results therefore illustrate how competition may, paradoxically, facilitate some aspects of group foraging in colonial animals.

Chronic high-dose testosterone disrupts social cognition and enhances social dominance in male long-Evans rats

While increased aggression is the most consistent behavioral effect of anabolic androgenic steroid (AAS) abuse, its cause remains unclear. AAS may promote aggression by disrupting social behaviors which maintain dominance hierarchies. To model AAS abuse, we treated male rats with chronic high-dose testosterone and tested social recognition, social learning, and competitive and aggressive dominance. Rats received daily injections s.c. of testosterone (7.5 mg/kg) or vehicle (n = 8/group). We tested social recognition by measuring investigation of a novel or familiar stimulus animal, social learning with the social transmission of food preference (STFP) test, aggressive dominance with the tube test, and competitive dominance with a food competition task. For social recognition, testosterone-treated rats did not prefer the novel stimulus rat (72.8 ± 9.3 s) over the familiar rat (68.8 ± 8.0 s, N.S.) rat. In the STFP test, testosterone-treated rats did not show a significant preference for the demonstrated flavor (59.9 ± 9.4 %, N.S.) compared with controls (70.1 ± 5.4 %, p < 0.05). In the tube test, testosterone did not increase the number of rounds won. However, when the testosterone-treated rat won, they were more likely to be lighter than their vehicle-treated opponent, χ2(1,N = 63) = 6.56, p < 0.05, Φ2 = 0.32. In the food competition task, testosterone-treated subjects won more often (48 rounds) than their vehicle-treated partners (15 rounds; p < 0.05). These results suggest that AAS disrupt recognizing and learning from the social hierarchy and increase the likelihood of challenging it. Collectively, these behavioral changes may contribute to AAS-induced aggression.

Customer Satisfaction Towards Food Delivery Services in Selangor

This study explores the key factors influencing customer satisfaction with food delivery services at UiTM Puncak Alam, Selangor. Despite the rising demand for food delivery services, issues surrounding the quality and accuracy of delivered food remain significant challenges. This study seeks to address these concerns by identifying and analyzing the determinants that shape customer satisfaction with food delivery services in Malaysia, specifically in Puncak Alam. We adopted a quantitative research approach to gain comprehensive insights into these issues. We collected data using judgment sampling, a non-probability sampling technique and used the Statistical Package for Social Sciences (SPSS) to analyze the responses through descriptive statistics and correlational analysis. The study involved a structured survey of 357 respondents, investigating the impact of three key variables—food quality, app ease of use, and food packaging—on customer satisfaction. The findings provide important implications for businesses and institutions looking to enhance the quality of food delivery services and elevate customer satisfaction levels. By identifying these critical factors, the research offers valuable insights that can help food service providers, policymakers, and industry stakeholders refine their strategies. These insights will not only improve the customer experience but also encourage broader adoption of food delivery services within the Malaysian population. Ultimately, the study’s conclusions hold significance for enhancing service quality and fostering customer loyalty in the increasingly competitive food delivery industry.

Gut bacteria facilitate leaf beetles in adapting to dietary specialization by enhancing larval fitness

Dietary specialization between insect stages can reduce intraspecific food competition. The involvement of gut bacteria and the mechanisms underlying this phenomenon received limited attention. Plagiodera versicolora is a pest harming Salicaceae trees. Here, we confirmed dietary specialization in P. versicolora, wherein adults prefer new leaves, while larvae predominantly consume mature leaves when both types are available. We demonstrated the larval preference for mature leaves confers ecological advantages by promoting growth, development and immunity and this advantage is contingent upon the presence of gut bacteria. Gut microbiota in larvae revealed a significant enrichment of Pantoea when feeding new leaves, with P. anthophila exhibiting the most pronounced inhibitory effect on larval development. Further exploration identified specific metabolites, such as Tyrosyl-valine, with higher content in new leaves, which serve as substrates for the entomopathogenic gut bacterium to facilitate its proliferation. This study provides a fresh perspective on the ecological role of gut bacteria.

BaYaka mothers balance childcare and subsistence tasks during collaborative foraging in Congo Basin

Across cultures, mothers balance childcare with other labour. Hunter-gatherer mothers face a daily choice of whether to take infants on foraging trips or leave them with caregivers in the settlement, as well as deciding with whom to forage. Yet, it remains unclear how infant presence affects mothers’ mobility and food returns during group foraging. Using GPS, heart rate measurements, and food return data from 348 foraging trips by 22 BaYaka mothers in the Republic of the Congo, we found that mothers go on longer-duration foraging trips when they take infants along, compared to when they leave them behind. Despite this, infant presence does not affect mothers’ mobility, energy expenditure, or food returns. Mothers also go on longer-duration and longer-distance trips during group foraging, compared to foraging alone. However, they have decreased food returns in larger groups with more adults, possibly due to food competition. Nevertheless, BaYaka mothers maintain their energy expenditure and net food returns in general, regardless of infant presence or group dynamics, likely due to their individual foraging strategies and support from group members. Particularly, children in foraging groups increase mothers’ food returns, aligning with women’s reports of children assisting as caregivers. These findings provide insights into how BaYaka mothers accommodate childcare with subsistence activities during group foraging.

The interplay of drought, human–wildlife conflict and food security: Insights from rural Zimbabwe

AbstractThe frequency and severity of drought has been increasing in Southern Africa against the backdrop of an increase in the population of both humans and wildlife, most notably elephants. This has increased the incidents of human–wildlife conflict (HWC) due to competition for food and water, further complicating both conservation efforts and food security for farmer‐households juxtaposed to wildlife corridors. We seek insights into these issues by examining the role of drought in inducing HWC in rural Zimbabwe and investigate the effect of HWC on the food‐security status of rural households. We utilise data from the 2023 nationally representative survey of rural Zimbabwean households in this endeavour. To avoid the confounding problem associated with self‐selection into a HWC household and taking into account the count nature of our outcome variable, we employ the endogenous switching regression model with count data. The results provide three major insights. First, drought occurrence increases the likelihood of HWC among rural farmer‐households. Second, HWC increases rural household vulnerability to food insecurity. Finally, the HWC shock is inconsequential on farmer‐household food insecurity if the farmer‐household has already suffered the drought shock.

Kazakhstani village: the need for radical transformation

Purpose - the tendencies of development of rural areas of Kazakhstan are shown. Methods - economic analysis, statistical methods were used in analyzing the data on the number of rural population in dynamics, graphical - for structuring the information and its visual presentation. Results - the article outlines the current trends and prospects of rural settlements (RS) of the republic, considers demographic processes, economic factors, migration flows. Special attention is paid to the state support initiatives aimed at improving the living standards of rural residents. The authors highlight the stages of building up the resources of rural areas of the country in the context of the implementation of state programs, each of which has specific goals and objectives aimed at improving the lives of rural residents, reducing their outflow from rural to urban areas caused by limited employment opportunities, low standard of living, insufficient access to quality services: education, health care. It is noted that in 20 regions of Kazakhstan adapted and implemented the program "One Village - One Product" (OVOP), focused on the production of the most promising products with high market potential, the creation of sustainable value chains of agricultural products for agricultural enterprises and farmers, promoting saturation of the domestic market with high-quality competitive food products. Conclusions - solving the problems of strengthening rural areas is in direct dependence on the effective policy of the state in the sphere of agro-industrial complex. Currently, emphasis is placed on the future of the Kazakhstani village, its modern infrastructure. Organizational, managerial and economic approaches, digitalization in agriculture allows to accelerate the pace of integrated socio-economic development of RS, increase the income of the rural population, stabilize the demographic situation and increase the investment attractiveness of territories.

Trophological studies for calculating the receiving capacity in the interests of artificial reproduction of sterlet in the Volga-Caspian Fisheries Subdistrict

The article presents the results of trophological studies of pass-through and riverine fish species in the root channel and delta of the Volga River. The aim of the work was to establish food competitors of juvenile sterlet from artificial reproduction in the places of its release and feeding. As a result, the nutrition spectra and the degree of filling of the digestive tracts of a number of cyprinid, catfish and goby fish species were studied. Based on the conducted studies, the daily rations and the frequency of occurrence of forage organisms in the food of each fish species were determined. The obtained materials are included in the calculation of the receiving capacity and serve as the basis for determining the optimal volume of release of factory sterlet juveniles into the watercourses of the Volga River in the Astrakhan region.

Capital Structure and Corporate Governance: Shaping Company Value through Dividends

Background: The dynamic interplay between corporate financial strategies, particularly capital structure and dividend policies, significantly influences firm value in the manufacturing sector.Knowledge Gap: While previous research has explored the direct relationships between capital structure and firm value, less attention has been paid to the moderating effects of dividend policy, profitability, and Good Corporate Governance (GCG) in this context. Aims: This study aims to assess the moderating roles of dividend policy, profitability, and GCG on the relationship between capital structure and firm value. Results: The findings indicate that dividend policy, profitability, and GCG significantly moderate the relationship between capital structure and firm value, suggesting that firms must balance dividend distribution with their capital structure decisions. Novelty: This research contributes to the existing literature by integrating dividend policy and GCG into the analysis of capital structure's effect on firm value, addressing previously overlooked aspects. Implications: The study underscores the importance of prudent dividend policies and robust corporate governance in enhancing firm value, offering valuable insights for managers and investors aiming to optimize financial performance in the competitive food and beverage manufacturing sector. Highlights : Moderating Effects: Dividend policy, profitability, and GCG significantly moderate the relationship between capital structure and firm value. Financial Balance: Firms must balance dividend distribution with capital structure decisions to enhance overall value. Managerial Insights: The findings provide crucial insights for managers and investors to optimize financial performance in the food and beverage sector. Keywords: capital structure, dividend policy, firm value, profitability, Good Corporate Governance

Cultural Familiarity and Its Impact on Customer Satisfaction and Brand Awareness

This study investigates the impact of food quality, service quality, pricing strategy, and marketing initiatives on patron satisfaction and brand recognition of Indonesian restaurants in Taiwan. It also examines how cultural familiarity moderates these relationships. A structured survey was conducted among 400 international patrons who dined at Indonesian eateries in Taiwan. Data were analyzed using Structural Equation Modelling (SEM) with Partial Least Squares (PLS) and moderation analysis. Findings reveal that food quality and pricing strategy significantly enhance customer satisfaction, while service quality and marketing efforts do not. Cultural familiarity strengthens the positive effect of food quality on satisfaction. This study underscores the importance of maintaining high food quality, implementing effective pricing strategies, and leveraging cultural familiarity for Indonesian restaurant owners in Taiwan. The research highlights the role of cultural factors in customer perceptions, contributing to the discourse on marketing strategies in the competitive food industry. The sample's focus on foreign customers in Taiwan may limit the broader applicability of the findings. Future research should consider factors like ambiance, location, and menu diversity for a comprehensive understanding of customer satisfaction and brand awareness

Analysis of the Interrelation and Seasonal Variation Characteristics of the Spatial Niche of Dominant Fishery Species-A Case Study of the East China Sea.

The spatial niche has garnered significant attention in ecological research, particularly regarding species distribution patterns. The East China Sea, known for its favorable natural conditions and abundant fishery resources, exhibits diverse spatial distribution patterns among species, shaped by their seasonal physiological needs. This study utilized a habitat suitability index model to explore the spatial distribution patterns of key fishery resources in the East China Sea across four seasons and their interactions. Two methodologies were employed to identify key environmental factors and assess the ecological niche overlap among different species and seasons. Results indicated that the initial method identified water temperature as the critical factor for hairtail, while the subsequent method emphasized water temperature and salinity for hairtail, salinity for small yellow croaker, and water depth for Bombay duck. The main spatial habitat overlap was observed between paired species, likely driven by predator-prey interactions. During summer and autumn, increased overlap among multiple species was primarily influenced by synchronized life cycles. An overlap index formula quantified the seasonal species overlap, showing an increase from spring to winter, reflecting changes in convergent habitat preferences. The peak overlap occurred in winter, driven by overwintering, reduced food competition, and enhanced coexistence potential, while the lowest overlap was noted in spring as overwintering ended and predation and competition intensified.

High early lactational synchrony within baboon groups predicts increased infant mortality.

Social group composition can have fitness implications for group members by determining opportunities for affiliative and competitive interactions. Female-female competition may be particularly acute when many groupmates have young infants at the same time, with potential consequences for infant survival. Here, we used decades of data on wild baboons (Papio sp.) in Amboseli, Kenya, to examine the effects of 'early lactational synchrony' (here, the proportion of females in a group with an infant <90 days old) on female-female agonistic interactions and infant survival. Because early lactation is an energetically demanding time for mothers and a risky time for infants, we expected early lactational synchrony to produce intensified competition for food and/or male protectors, resulting in more frequent female-female agonistic interactions and high infant mortality. In support of these predictions, we found that the frequency of female-female agonistic interactions increased with increasing early lactational synchrony. Reproductive state affected this relationship: while females in all states (cycling, pregnant, and postpartum amenorrhea) initiated more agonistic interactions when early lactational synchrony was high, only females in postpartum amenorrhea (including, but not limited to, females in early lactation) received more agonistic interactions. Furthermore, while high early lactational synchrony was rare, it strongly predicted infant mortality. This association may result from both aggression among adult females and infanticidal behavior by peripubertal females. These findings provide novel evidence that social dynamics may shape reproductive phenology in a nonseasonal breeder. Specifically, both competition among reproductive females and harassment from nonreproductive females may select against synchronous reproduction.

Последствия распространения коронавируса COVID-19 и новых штаммов для развития агропромышленного комплекса и потребительского рынка

The COVID-19 pandemic has become an example of the implementation of global biological threats, which are positioned as challenges to the economy, including the agricultural sector. The subject of the study was changes in food production and in the consumer market for agricultural products amid the consequences of the spread of the COVID-19 coronavirus and potentially dangerous new strains. Since the volume and structure of agricultural exports can serve as indicators of overcoming the challenge to the agro-industrial complex from the consequences of the COVID-19 pandemic, including in conjunction with the influence of the sanctions policies of Western countries, the object of the study was changes in the main indicators of exports of the agro-industrial complex of the Russian Federation at the federal and regional levels for first quarter of 2023 compared to the same period in 2022. Changes in the main indicators of exports of agricultural products were studied both at the federal and regional levels, using the example of agricultural enterprises in the Voronezh region, for the first quarter of 2023 compared to the same period in 2022. As a background for studying the subject field of indicators for overcoming the challenge to the agro-industrial sector from the consequences of the COVID-19 pandemic, changes in the field of food production and in the consumer market for agricultural products were identified and studied. An overview of the main exporting companies in the Voronezh region is presented for the following types of products: grains (wheat, corn, barley); meat and dairy products (pork and pork by-products, beef, butter); products of the oil and fat industry (sunflower oil, cakes, mustard oil). The priority trend for the Russian Federation is the development of deep processing of crop products, in particular grain crops. The basis is the trend of growing consumer demand for food products of plant origin, including those that imitate traditional meat and dairy products. A trend has been noted for the production and consumption of organic products, the implementation of which will contribute to the growth of the competitiveness of domestic agricultural products in the domestic and foreign markets. An important factor in increasing the competitiveness of domestic food in the global and domestic markets is the expansion of production of organic crop and livestock products based on a single unified database of agricultural land that meets the legally established requirements for this category of products.

Northern Gannet foraging trip length increases with colony size and decreases with latitude

Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species’ latitudinal range is poorly understood. Here we used satellite tracking from 21 Northern Gannet Morus bassanus colonies (39% of colonies worldwide, supporting 73% of the global population) during chick-rearing to test how foraging trip characteristics (distance and duration) covary with colony size (138–60 953 breeding pairs) and latitude across 89% of their latitudinal range (46.81–71.23° N). Tracking data for 1118 individuals showed that foraging trip duration and maximum distance both increased with square-root colony size. Foraging effort also varied between years for the same colony, consistent with a link to environmental variability. Trip duration and maximum distance also decreased with latitude, after controlling for colony size. Our results are consistent with density-dependent reduction in prey availability influencing colony size and reveal reduced competition at the poleward range margin. This provides a mechanism for rapid population growth at northern colonies and, therefore, a poleward shift in response to environmental change. Further work is required to understand when and how colonial animals deplete nearby prey, along with the positive and negative effects of social foraging behaviour.

Food composition and trophic niches of blue swimming crab (Portunus pelagicus, 1758) in Madura Strait, Pamekasan, East Java

Abstract Blue swimming crab (Portunus pelagicus) is the main fishery commodity in the Madura Strait, Pamekasan Regency. The sustainability of the crab depends on the suitability of the habitat and the availability of food in the waters. This study aims to analyze the food composition and trophic niches of blue swimming crab in the Madura Strait, Pamekasan Regency. Sampling was conducted using the simple random sampling technique. The analysis included composition of the collection based on length frequency distribution, gastric fullness index, trophic niche area, food niche overlap, crab food composition, and growth (carapace width-weight relationship, and condition factor). The results of the index study showed that the index of stomach content of the female was generally greater than that of the male. Blue swimming crab is classified as a carnivore with the main food being fish. The overlap of the niches of male and female crabs of 0.9328 indicates a high level of competition for food. The male crab has a negative allometric growth pattern, while the female crab has a positive allometric growth pattern. The condition of the crab factor in each month of observation is greater than 0.5 indicating the availability of food and water conditions suitable for crab life.