Seasonal Migration Research Articles

Development of virtual hunting tourism as the basis for the conservation of pristine wildlife

Many people in today's society still enjoy hunting as a hobby to relax and disconnect from their busy daily lives. The Crimean Peninsula, located on the Black Sea coast, is not only famous for its history, natural landscapes and resorts, but is also one of the most popular places for hunting tourism. Magnificent natural conditions, a variety of wildlife and seasonal migrations make the peninsula an ideal place for hunting and adventure, surrounded by spectacular scenery. Crimean hunting tourism offers a unique opportunity not only to plunge into the world of hunting passions, but also to enjoy all the delights of the peninsula. The relevance of studying the development of a tourist and recreational hunting tourism project is due to the actively developing market for the provision of services in the field of hunting in our country. But the hunting resources of the Crimean forests are not limitless. The possibility of replacing real hunting tourism with virtual tourism with the help of modern IT technologies (VR, AR) is the goal of our research. Thanks to this approach, a potential hunter can feel like he is in a real wild environment, but at the same time know that his life is not in serious danger. In addition, the important task of preserving endangered animal species in the wild is being solved.

Lice (Phthiraptera, Amblycera, Ischnocera) collected on the birds in the Aras basin in Iğdır Province, Türkiye with new records and new host associations.

Chewing lice (Phthiraptera, Ischnocera and Amblycera) are permanent ectoparasites of birds and primarly feed on the feathers and scales of birds. To detect the chewing lice species found on birds in Aras basin, Igdir, Türkiye, a total of 240 birds represented by 61 species belonging to 30 families in 13 orders were examined during the 2021 bird migration season. A total of 531 (186 females, 136 males and 209 nymphs) lice were collected from 75 individuals (31,25% of birds examined) of 26 species, 21 families and 10 orders. Thirty-one lice species (11 amblyceran and 20 ischnoceran species) in 22 genera were identified. Of these, 15 lice species were reported for the first time in Türkiye, namely Cuculiphilus fasciatus, Pseudomenopon qadrii, Philopterus sp., Ricinus serratus, Philopterus picae, Rostrinirmus buresi, Sturnidoecus sp., Philopterus excisus, Philopterus microsomaticus, Philopterus coarctatus, Brueelia fuscopleura, Sturnidoecus pastoris, Brueelia currucae, Penenirmus auritus and Strigiphilus tuleskovi. In addition, new host associations were reported for the lice species Kurodaia fulvofasciata, Degeeriella rufa and Myrsidea rustica.

SEASONAL MIGRATION FROM RURAL AREAS WITH SPECIAL REFERENCE TOCHOTANAGPUS REGION OF SJHARKHAND STATE

The liberalization period witnessed the increasing crisis in the agriculture and allied sector that supports a large chunk of the population and subsequently, the slow and gradual displacement of the millions of people from their traditional livelihoods result in increasing underemployment and unemployment in rural areas. This scenario has pushed the people to opt for migration for livelihood expansion. Migration is best understood as one of the strategies adopted by individuals, households or communities to enhance their livelihoods because in general migration has a function of reducing vulnerability – effective migration strategies helps people to reduce the risks of seasonality, harvest failure, etc. Present paper analyzes seasonal migration from remote tribal villages of South Chotanagpur in Jharkhand.

ON THE COLONISATION OF THE CENTRAL RUSSIAN PLAIN IN LATE GLACIAL AND EARLY HOLOCENE ACCORDING TO GEOARCHAEOLOGICAL DATA

Until recently, interpreting archaeological data on the colonisation of the Central Russian Plain during the last glacial epoch (Late Valdai, Vistulian) had been hampered by the prevailing view that vast areas along the ice sheet boundary were submerged by large proglacial lakes. Under the hypothesis that the Tver proglacial lake was covering Upper Volga lowlands and the Dubna depression, these territories would not be habitable until the Pleistocene-Holocene boundary when they finally dried up in the process of deglaciation. In 2018-2021, geoarchaeological investigations were carried out in Zabolotsky peatland (Moscow Region) to test this hypothesis. It was found that during the whole Late Valdai (Vistulian) glacial epoch, the prevailing environmental conditions in the Dubna Lowland were fluvial, rather than lacustrine. Thus, it is entirely plausible that large parts of the Zabolotsky area could already start to become populated at that time. AMS-dating of resin samples from the grooves of bone and hornbeam artefacts attributed to Epigravettian Resseta culture pinpoint the potential timing of this event to circa 15,500 cal BP. During Early Holocene, Zadnepilevo industry was the successor to Resseta tradition. Other populations known to exist in Central Russian Plain during late Pleistocene – early Holocene are attested from Bromme, Ahrensburg, Kultino and Purgasovo culture complexes. The identification of Elin-Bor, Butovo and Ienevo cultures in the Volga-Oka basin during the Mesolithic had been made by tampering with primary data. Therefore, any further allusion to these cultures would be unethical Seasonal migration patterns of both Resseta and Zadnepilevo populations are evidenced not only by data from the Russian Plain, but also from the Scandinavian Peninsula. Here, they are represented by the so-called "eastern pulse" industry. To piece together the cultural and historical development of Eastern and Northern Europe, a substantial increase in field research is needed.

Some data on status of the herd of horsehair crab (<i>Erimacrus isenbeckii</i>) in the northwestern Tatar Strait

The data of trap surveys and observations aboard fishing vessels conducted in the northwestern Tatar Strait (northward from Cape Zolotoy) in 2009–2022 are analyzed. Horsehair crabs dwell along the entire continental coast from Cape Zolotoy in the south to Cape Nakatov in the north, but commercial aggregations with the density on average 232 ind./km2 are concentrated in the southern part of this area (south of 49о N). Seasonal bathymetric migrations of the crab include the fall moving of commercial males from the depths of 10–40 m to the depths of 40–60 m for wintering and their return to shallows in spring. Two dense wintering aggregations are formed usually between Cape Peschany – Cape Mapatsa and southward from 48о00′ N, whereas sparse summer aggregations are widely distributed along the coast. Regardless the season, the aggregations density decreases from south to north. The males are generally larger in the southern aggregations than in the northern ones (on average, 100.3 and 89.8 mm of carapace width, respectively), the difference is statistically significant (p < 0.0001). The stock of horsehair crab in the northwestern Tatar Strait has increased in the last 20 years from136 tons in 2003 to 1580 tons in 2022. Over the past 10 years, the optimal allowable catch in the Primorye subzone north of Cape Zolotoy was utilized less than 50 %. There is no specialized fishery of horsehair crab; the species is caught mainly as bycatch for other shelf crab species. High current level of the stock gives a good background for commercial removal of at least 158 t of horsehair crab without damage to the local population of this species.

Endocrine mechanisms controlling the migratory disposition in birds

On Earth, billions of birds make seasonal migrations every year. Some species fly thousands of kilometers, overcoming seas, mountains and deserts on their way. For migration to be successful, birds must have perfect mechanisms for controlling its beginning, duration and termination. On the way, birds have to make many decisions: how much in energy reserves to accumulate; when to depart, how long and in which direction to fly; how to select optimal weather conditions for flight; and, finally, when and where to terminate migration. Prior to migration, birds develop a migratory disposition – a suite of changes in physiology and behavior (e.g. migratory fattening and expression of nocturnal migratory activity) which are typical for this important life-history stage. Such physiological changes and migratory behavior are the subject of hormonal regulation. The central structure that controls activity of various hormonal systems and development of migratory disposition is the hypothalamic-pituitary system. The hypothalamus controls the secretion of regulatory hormones by the pituitary gland and these hormones, in turn, regulate the activity of downstream endocrine glands. It has been established that spring migratory disposition is triggered by an increasing photoperiod, which stimulates the production of testosterone, prolactin and modulates the signaling of thyroid hormones. In contrast, it is practically unknown how autumn migratory disposition develops when the photoperiod decreases and does not stimulate release of the abovementioned hormones. While in migratory disposition, the endocrine control of behavior on the smaller temporal scales (for example, the level of fuel accumulation, or decision to depart from a migratory stopover) is associated with the combined action of melatonin, corticosterone, insulin, glucagon, adipokines, and other hormones and neurotransmitters. In this review, I will describe the role of these hormones in the control of migratory traits, highlight the existing inconsistencies, and present possible ways to progress in this area of research. A knowledge of endocrine regulation of migratory behavior will help to predict the limits of species adaptability, explain current population trends, and inform conservation actions, which is especially important in the light of modern climate change and anthropogenic transformation of landscapes.

To hear or not to hear: selective tidal stream transport can interfere with the detectability of migrating silver eels in a Tidal River

Acoustic telemetry provides valuable insights into behavioural patterns of aquatic animals such as downstream migrating European eels (Anguilla anguilla), so called silver eels. The behaviour of silver eels during the migration is known to be influenced by environmental factors, yet so is the performance of acoustic telemetry networks. This study quantifies the impact of these environmental factors on both, migration behaviour and receiver performance to determine possible limiting conditions for detecting tagged eels in tidal areas. A dominance analysis of the selected models describing migration speed, activity and receiver performance was conducted following 234 silver eels that were tagged with acoustic transmitters and observed by a receiver network in the Ems River during two subsequent migration seasons. The results suggest a passive locomotion of silver eels during their downstream migration by taking advantage of selective tidal stream transport (STST). It is further shown that water temperature, salinity, turbidity, precipitation, and especially current velocity were major parameters influencing migration activity and speed. At the same time, analyses of the detection probability of tagged eels under varying environmental conditions indicated a decreased receiver performance during increased current velocities, meaning that high migration activity and -speed coincides with reduced detection probability. Consequently, there is a risk that particularly during phases of increased activity, migration activity may be underestimated due to reduced acoustic telemetry performance. To avoid bias in telemetry studies, it is, therefore, crucial to conduct range tests and adjust the receiver placement in areas and conditions of high current velocities.

Сучасний стан гніздування журавля сірого (Grus grus) у Хмельницькій області

The present study summarizes the data, concerning the historical and the current status of the nesting population of the common crane on the southern margin of its nesting area on the Khmelnytskiy region territory, based on the analysis for 1800–2022. In the chronological plane the common crane is indicated as nesting, migratory (1800–1950), migratory (1951–1980), nesting, migratory (1981–1998), nesting (1993–1994), nesting, migratory (1999–2015). Based on the information presented in the article, as of 2022, the common crane in Khmelnytskiy region is a rare, nesting, migratory bird and common during seasonal migration. The material, presented in the article by the authors over the period of 2000–2022 as part of individual studies, reveals the current state of the nesting, number and some aspects of the nesting ecology. Thus, during the study period, 37 occurences of the species in the nesting season were recorded. The estimated nesting population in the study area accounts 21–25 pairs. Wetland complexes, which have status of the nature reserve fund objects of the local and national importance, where the 72.0–85.7 % of the local pairs of the total population in the region are concentrated. The Maliovanka Regional Landscape Park is of great importance for the protection and conservation of the species, where 60.0–71.4 % of the regional nesting population are concentrated. According to our data (n=34) the common crane individual nesting grounds in the nesting season were found in 3 types of landscape – the marshy banks of the decayed peat mines (39,4 %), transitional mesotron bogs (36,3 %) and swampy forests (mainly alder) in the floodplains of the small forest rivers (Lizne, Hnylyi Rih, Vilia). It has been established that the species has dispersed over the past 20 years in the westerly vector across the entire width of the Male Polissia from the Zhytomyr region towards the Rivne region. This is also confirmed by the findings of the territorial pairs in the last decade in the Male Polissia in Rivne and Lviv regions. It has been established, that the most suitable conditions for the nesting are in the eastern part of the Male Polissia in Khmelnytskiy region, due to the presence of the westland complexes, including the revived older peat mines of the 40–60s of the XX-th century. The presented in this article data may become a starting point for further monitoring and protection of the species.

Movement behaviour of the common frog (Rana temporaria) in an anthropized mountain landscape: integrated step selection analysis of GPS tracking data

Abstract Movement is a key aspect of amphibian ecology as the life cycle of many species involves seasonal dispersal and migration. However, there is still a lack of knowledge about how amphibians move across landscapes in relation to landscape structure and resource availability. Modern lightweight GPS loggers and associated statistical tools offer new perspectives to fill this gap. We tracked the movements of 20 adult European common frogs (Rana temporaria) in a human-transformed mountain landscape during summer using GPS tags programmed with a constant 4-hour time interval between fixes. Using integrated step-selection analysis, we demonstrate firstly that frogs strongly selected aquatic habitats over open grassland. Second, ski runs have a negative effect on frogs, indicated by longer movement steps. Weather (air temperature and rain) had no effect on frog movements. These results constitute a promising first step towards studying anuran movement in relation to landscape structure at fine spatial and temporal scales.

RELIGIOUS SYNCRETISM, SUFISM AND THE ROLE OF ISHANS IN NOMADIC KAZAKH SOCIETY

The article investigates the influence of the natural-geographical environment of Kazakhstan on the process of rooting Sufi traditions and religious syncretism in the medieval nomadic Kazakh society. The article identifies the main routes of seasonal migration and specific features of the nomadic process in medieval Kazakh society and indicates the cause-and-effect relationship between the theory of geographical determinism and the spread and rooting of Sufi traditions in local culture. Particular scientific attention in the article is paid to the phenomenon of the later Sufi tradition, known as “Ishanism”, which has been studied in this article in the context of the socio-political developments that took place in the nomadic Kazakh society of the early 18th - late 19th centuries. This gives an understanding of why the religious mission of the Ishans succeeded in the process of reintroducing the Kazakhs to Islamic traditions. Eventually it should be assumed that their religious and missionary activities lay on the fertile soil of the social and political realities, which had matured by that time among the nomadic Kazakh society and thus gave this process a powerful spiritual impulse and dynamics.

Side Effects of Single-Transgene or Pyramided Genetically Modified Maize on the Generalist Endoparasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)

The fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), is an agricultural pest native to tropical and subtropical regions of the Americas, with considerable potential for global invasion and seasonal migration. Although genetically modified (GM) plants have shown positive impacts on the economy and the environment as they synthesize proteins that act as natural insecticides and are primarily intended to protect the crops from damage by specific pests, potential effects of Bt toxins on non-target organisms can occur. This experiment aimed to evaluate the potential impacts on the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae), using the pupae of Spodoptera frugiperda (Lepidoptera: Noctuidae) as hosts, which were fed with transgenic maize genotypes such as Herculex®, expressing Cry1F protein, and PowerCore®, expressing Cry1F, Cry1A.105, and Cry2Ab2 proteins, or their non-transgenic isohybrid. The experiment was conducted in a completely randomized design with ten replicates. Spodoptera frugiperda larvae were fed ad libitum with transgenic and non-transgenic maize until the pupal stage and then individually exposed to six P. elaeisis females for 78 h. The total number of adults, emerged males, tibia size, cephalic capsule size, and parasitoid body size were not influenced by host feeding. However, the number of emerged females from the Herculex® and PowerCore® treatments was lower than that for the isohybrid treatment. The sex ratio and longevity of parasitoids emerging from PowerCore® were 1.05 and 1.26 times lower, respectively, than that of those from the isohybrid. Furthermore, the number of dead P. elaeisis within the host pupa was 10.56 times higher in the PowerCore® genotype. Combining Bt proteins within pyramided genotypes should cause minimal impacts and promote the conservation and integration of beneficial insects. The results of this study provide helpful information for developing effective and compatible integrated pest management (IPM) strategies.

Labour Force Composition and Labour Shortage in North-Western Romania: A Cross-County Comparison1

Abstract The paper analyses the labour force composition of two adjacent counties in north-west Romania: Maramureș and Sălaj. Regionally, employers stress the lack of available labour force and resort to commuter networks from nearby rural areas and immigrant labour. Why labour shortage? It is argued that Romania’s FDI-reliant export-led growth model factors in. Namely, the growth model’s reliance on low-cost labour that reduces employment incentives to a minimum (often minimum wage) and employment in repetitive labour-intensive activities make the prospect less attractive. If technological upgrading – requiring skilled employees – is absent, regional labour availability tends to be an issue. Alternative subsistence methods are favoured: seasonal transnational migration, household agricultural subsistence and remittances from relatives. Tying livelihood to families and households, these methods pool resources to replace (even if in part) wage labour under global market-dependency conditions.

Striped Bass Movement in a Large Southeastern River System

Abstract Migratory behaviors of coastal Striped Bass Morone saxatilis are diverse and vary by latitude along the U.S. Atlantic Coast. Northern populations (e.g., north of Cape Hatteras, North Carolina) are anadromous, with spawning occurring in tidal freshwater/brackish rivers and adults leaving spawning locations during the winter to conduct north–south coastal migrations. The central Atlantic comprises a mixture of potamodromous and anadromous types, completing the natural continuum of behavioral modes along latitudinal ecotones. Southern populations (e.g., south of Cape Hatteras, North Carolina) are typically resident and potamodromous, completing full life cycles within river systems, and do not migrate along the Atlantic Coast. There are limited studies that have investigated daily movement of Striped Bass in the Southeast and no studies have documented movement of Striped Bass in the Great Pee Dee River, particularly with reference to spawning migrations. The objective of this study was to describe daily movement patterns and centers of attraction (e.g., spawning and resting stages) of Striped Bass in the Great Pee Dee River, South Carolina. We implanted 10 fish with hydroacoustic transmitters between 2013 and 2016. We describe daily movement and behavior using the state-space model with a two-dimensional spatial coordinate system. We recorded a total of 94,857 data points across all individuals and receivers. We observed two movement patterns. One group completed a seasonal migration (i.e., were recorded swimming upstream or downstream) that coincides with spring spawning season. A second group was present in the lower river section and Winyah Bay during the winter for 3 consecutive years but were never observed migrating up the Great Pee Dee River during the spring. One individual was documented swimming 80 river km north in the Atlantic Intracoastal Waterway, suggesting there are important overwintering locations outside their natal river. Additionally, there were significant gaps in observations for all individuals, particularly in the summer. It is possible that fish are leaving the main stem in search of thermal refuge within small tributaries. Identifying these overwintering areas and tributaries that serve as summer refuge is needed to determine stressors and fishing pressure of this important species.

Affordable Rental Housing for the Urban Seasonal Migrants in India

Affordable Rental Housing for the Urban Seasonal Migrants in India

A novel RT-qPCR health assay reveals differential expression of stress and immunoregulatory genes between the seasonal migrations of humpback whales (Megaptera novaeangliae).

Health information is essential for the conservation management of whale species. However, assessing the health of free-ranging whales is challenging as samples are primarily limited to skin and blubber tissue. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) offers a method to measure health from blubber RNA, providing insights into energetic status, stress and immune activity. To identify changes in health, natural differences in baseline gene expression linked to an individual's sex, reproductive status and life-history stage must first be quantified. This study aimed to establish baseline gene expression indices of health in migrating humpback whales (Megaptera novaeangliae). To do this, we developed an assay to quantify seven health-related gene transcripts (Leptin, Leptin Receptor, Adiponectin, Aryl Hydrocarbon Receptor, Tumour Necrosis Factor-α, Interleukin-6, Heat Shock Protein-70) and used Bayesian mixed effect models to assess differential baseline expression based on sex, lactation status and migration stage (northbound to and southbound from the annual breeding grounds). Results showed no significant contribution of sex to differential baseline expression. However, lactating individuals exhibited downregulated AhR and HSP-70 compared to non-lactating conspecifics. Additionally, southbound individuals demonstrated significantly upregulated HSP-70 and downregulated TNF-alpha, suggesting a relationship between these inflammation-linked transcripts and migratory fasting. Our results suggest that baseline differences due to migratory stage and lactation status should be considered in health applications of this assay. Future monitoring efforts can use our baseline measurements to better understand how gene expression is tied to population-level impacts, such as reduced prey availability or migratory stressors.

The environmental cost of cryptocurrency: Assessing carbon emissions from bitcoin mining in China

This study estimates the environmental impacts of Bitcoin mining. Employing a top-down measurement approach, this paper assesses the carbon footprint of Bitcoin mining in China from 2017 to 2021. The findings reveal that mining activities during this period contributed to a total of 77.84 million tons of carbon dioxide emissions in China. By utilizing data at the provincial level, we find that the seasonal migration of Bitcoin mining pools will lead to regional power demand shocks in China. Additionally, this study predicts future carbon emissions from Bitcoin mining in China, projecting cumulative carbon dioxide emissions of 76.40 million tons and 722.18 million tons by 2030 and 2060 respectively, in the absence of any policy interventions. Based on these findings, this paper posits that governments worldwide should make efforts to restrict the carbon emissions from Bitcoin mining and opt for environmentally friendly technological methods to fundamentally alleviate Bitcoin's reliance on energy. The implication for central banks is that carbon emission should be taken into consideration when designing the central bank digital currencies (CBDCs).

Коммуникативная функция ольфакторных образов в романах П. Зюскинда «Парфюмер» и Т. Салиха «Сезон миграции на Север»

The article deals with the comparison of olfactory images in Patrick Suskind’s novel Perfume and Tayeb Salih’s The Season of Migration to the North in the communication context of Arab and European cultures. The initial theoretical point, based on the existing developments in the field of literary studies and cultural studies, is the idea of olfactory images as an essential component of the poetics of a work of art. The role played by olfactory images in revealing the characters of the two heroes Jean-Baptiste Grenouille and Mustafa Said is considered. Both heroes share similarities: on the one hand, they have a gift, and on the other, they are alienated from society: they feel lonely, their position in the world is that of an outcast. However, for Grenouille, this alienation is due to his personal features, while Mustafa Said’s psychological problems are connected with the colonial past of his homeland, Sudan. With the help of fragrances, both heroes are trying to restore the destroyed communication links – to evoke love to themselves and assert themselves. The article examines the relationship between olfactory images and the image of the homeland of both heroes. In the novel Perfume, the olfactory image of Paris is represented exclusively in a repulsive way. In the novel The Season of migration to the North, smells, by contrast, return the hero to his childhood, help him achieve harmony with himself and with nature. Olfactory images play an important role in revealing the problem of the protagonist’s communication with women. Grenouille artificially creates a fragrance that causes erotic temptation in the people around him. Salih’s novel also shows the connection between olfactory images and the motives of seduction, however, Mustafa Said does not create artificial smells, but uses natural smells to arouse the interest of his potential victims. The article concludes that the communicative functions of olfactory images in both novels are similar, but their differences are determined by the specific features of Arab and European culture.

Mountain agropastoralism: traditional practices, institutions and pressures in the Indian Trans-Himalaya of Ladakh

Animal husbandry of agropastoral communities in the mountainous region of Leh, Ladakh, has been transformed in response to socio-economic and geo-political changes. This study investigates the current state of agropastoralism in the Trans-Himalaya of Leh, Ladakh, focusing on two objectives: understanding grazing management practices and examining socio-environmental factors affecting traditional pastoral livelihoods. Through a mixed-methods approach, including interviews and focus group discussions, this study explores resource utilisation patterns and decision-making processes within local communities and institutions based on a comparative approach in three pastoral areas of Ladakh. The resource utilisation pattern differs from village to village as a response to meet seasonal fodder demands; accordingly, high-altitude pastures are assessed in winter and/or summer seasons. Key stresses to the perpetuation of traditional pastoral knowledge include livelihood diversification, increasing dependence upon exogenous food production system and diminishing significance of traditional livelihood practices with improved connectivity, higher education aspirations and development of tourism and military services. Broadly, changes could be perceived from the abandonment of regular seasonal migration to pasturelands, in livestock composition and size and the decreasing number of households practising animal herding. Apart from socio-economic and developmental pressures, pastoral practices are simultaneously threatened by wild predators as well as by global warming-induced occurrence of extreme climatic events and pest attacks. While pastoral practices are carried on by a limited number of households in the three detailed study sites, knowledge pertaining to resource management, pastureland system and grazing pattern is still intact considering the resource seasonality and range of social and environmental pressures the region experiences. Ladakh’s agropastoral practices, rooted in local ecological knowledge, face challenges from socio-economic changes, risking climate resilience, ecosystem degradation, cultural loss and food security for agropastoral communities and broader societal contexts. Thus, it becomes vital to safeguard these indigenous livelihood practices and to promote a participatory approach to enhance capacity building for the continuation of the practice, which could contribute to local economies in areas with similar socio-environmental settings.

Nonconsumptive effects of black sea bass (Centropristis striata) on a crustacean mesopredator and the indirect effects on bivalve survival

The consumptive and nonconsumptive effects of predators on their prey and the indirect effects of these interactions that cascade through food webs have been studied for over half a century. In the northwest Atlantic, the stock of black sea bass (Centropristis striata) steeply declined during the 1980s. While population crashes of fished bivalve species coincided with those of black sea bass, the role of black sea bass in driving trophic cascades that indirectly influence bivalve survival has largely been overlooked. Over the past decade, black sea bass have not only been recovering in abundance but warming water temperatures have been driving a northward expansion of the extent of their seasonal migration, resulting in a particularly strong relative recovery along the south shore of Long Island, New York. To explore whether black sea bass alter the foraging rates of mud crabs (Dyspanopeus sayi) on a species of bivalve, blue mussels (Mytilus edulis), we manipulated the presence and position of sea bass within an array of mesocosm tanks. We found that the presence of black sea bass reduced the proportion of blue mussels consumed by mud crabs. Black sea bass presence indirectly elevated blue mussel survival by as much as 47.7% by reducing mud crab per capita consumption of blue mussels by 57.9%. However, there were limitations to the nonconsumptive effects of black sea bass that appeared to depend on their proximity to mud crabs. While our results are from an experimental setup with a simplified food chain and are context dependent, they emphasize the importance of studying how nonconsumptive effects of specific marine predators influence trophic cascades from both conceptual and applied coastal resource management standpoints. Our results suggest that the recovery of black sea bass may bode well for the population restoration of several species of bivalves within estuaries throughout their range. Further, our study provides evidence that indicates that the nonconsumptive effects of a recovering marine predator can indirectly elevate the survival of a basal food resource species.

Encouragement and distortionary effects of conditional cash transfers

Conditional cash transfer (CCT) programs aim to reduce poverty or advance social goals by encouraging desirable behavior that recipients under-invest in. An unintended consequence of conditionality may be the distortion of recipients’ behavior in ways that lower welfare. We first illustrate a range of potential distortions arising from CCT programs around the world. We then show that in the simple case where a CCT causes low return participants to select into a behavior, and social returns and private perceived returns are aligned, transfer size plays an important role: the larger the transfer, the stronger the distortion becomes, implying that (i) there is an optimal transfer size for such CCTs, and (ii) unconditional cash transfers (UCTs) may be better than CCTs when the transfer amount is large. We provide empirical evidence consistent with these claims by studying a cash transfer program conditional on seasonal labor migration in rural Indonesia. In line with theory, we show that when the transfer size exceeds the amount required for travel expenses, distortionary effects dominate and migration earnings decrease.