Changes In Distribution Patterns Research Articles

Predatory zooplankton on the move: Themisto amphipods in high-latitude marine pelagic food webs.

Hyperiid amphipods are predatory pelagic crustaceans that are particularly prevalent in high-latitude oceans. Many species are likely to have co-evolved with soft-bodied zooplankton groups such as salps and medusae, using them as substrate, for food, shelter or reproduction. Compared to other pelagic groups, such as fish, euphausiids and soft-bodied zooplankton, hyperiid amphipods are poorly studied especially in terms of their distribution and ecology. Hyperiids of the genus Themisto, comprising seven distinct species, are key players in temperate and cold-water pelagic ecosystems where they reach enormous levels of biomass. In these areas, they are important components of marine food webs, and they are major prey for many commercially important fish and squid stocks. In northern parts of the Southern Ocean, Themisto are so prevalent that they are considered to take on the role that Antarctic krill play further south. Nevertheless, although they are around the same size as krill, and may also occur in swarms, their feeding behaviour and mode of reproduction are completely different, hence their respective impacts on ecosystem structure differ. Themisto are major predators of meso- and macrozooplankton in several major oceanic regions covering shelves to open ocean from the polar regions to the subtropics. Based on a combination of published and unpublished occurrence data, we plot out the distributions of the seven species of Themisto. Further, we consider the different predators that rely on Themisto for a large fraction of their diet, demonstrating their major importance for higher trophic levels such as fish, seabirds and mammals. For instance, T. gaudichaudii in the Southern Ocean comprises a major part of the diets of around 80 different species of squid, fish, seabirds and marine mammals, while T. libellula in the Bering Sea and Greenland waters is a main prey item for commercially exploited fish species. We also consider the ongoing and predicted range expansions of Themisto species in light of environmental changes. In northern high latitudes, sub-Arctic Themisto species are replacing truly Arctic, ice-bound, species. In the Southern Ocean, a range expansion of T. gaudichaudii is expected as water masses warm, impacting higher trophic levels and biogeochemical cycles. We identify the many knowlegde gaps that must be filled in order to evaluate, monitor and predict the ecological shifts that will result from the changing patterns of distribution and abundance of this important pelagic group.

Rainfall forecasting using PSPline and rice production with ocean-atmosphere interaction

The role of climate can be affected by plants. The weather can accelerate and multiply the existence of various plant pests and diseases, accelerate the growth and development of grass among plants, and encourage the emergence of infection and significant damage to plants. The elements of climate that affect the growth of plants are one of them is rainfall. In this paper, we performed the simulation using the non-parametric penalized spline (PSPLINE) method and studied the effect on rice production in Lampung. It can be concluded that the increasing fluctuation, frequency, and intensity of climate anomalies in the last decade caused by the ENSO phenomenon have an impact on changes in distribution patterns, intensity, and period of the wet season so that the start of the rainy season and the dry season becomes too late. As a result, there is a seasonal shift from normal average conditions that can ultimately have severe implications for food crops. In a nutshell penalized spline gives high accuracy with R2 = 96.227% and MAPE = 1.62%.

Spatio-Temporal Changes of Oases in the Hexi Corridor over the Past 30 Years

In recent decades, the oases in the Hexi Corridor have gone through a tremendous transformation, which has caused a series of social and environmental problems. We aim to explore quantitatively the characteristics of the oasis expansion and their dynamic mechanism(s) in the Hexi Corridor, and their implications and impact on current and future policies. The spatial distribution pattern and dynamic changes experienced by the oases are examined using Landsat imagery. Their spatio-temporal changes are analyzed using the grid-transformed model and the dynamic-degree model. The model drivers are analyzed based on data from statistics yearbooks and field surveys. The total area of oases in the Hexi Corridor has expanded tremendously during the last 30 years from 10,709 km2 to 14,950 km2, almost 40% of the original value. Oasis evolution patterns of ‘unchanged’, ‘expanding’, ‘shrinking’, and ‘oscillating’ are observed at different periods in the three basins. In terms of area, almost half of the oases experienced some change, where most of the changes took place in the ecotone between oases and deserts, and the interior of oases due to the reclamation of abandoned land. Oasis expansion is mainly determined by the human instincts for survival and well-being, which are generally governed by population growth, agricultural policies and economic development. These changes reflect the need to find a balance in the relationship between ecological protection and increasing the well-being of local residents, because unreasonable or excessive development and utilization will cause damage to the local ecological environment.

Operational offshore wind farms and associated ship traffic cause profound changes in distribution patterns of Loons (Gavia spp.)

Seabirds select suitable habitats at sea, but these habitats may be strongly impacted by marine spatial planning, including the construction of offshore wind farms (OWFs) and the associated ship traffic. Loons (Gavia spp.) are particularly vulnerable to anthropogenic activities and are also of high conservation status, making them particularly relevant to marine planning processes. We investigated the effects of OWF construction and ship traffic on Loon distributions in the German North Sea on a large spatial scale, using a ‘before–after’ control impact analysis approach and a long-term data set. Many OWFs were built in or close to core areas of Loon distributions. Loons showed significant shifts in their distribution in the ‘after’ period and subsequently aggregated between two OWF clusters, indicating the remaining suitable habitat. The decrease in Loon abundance became significant as far as about 16 km from the closest OWF. Ship traffic also had a significant negative impact on Loons, indicating that OWFs deterred Loons through the combined effect of ship traffic and the wind turbines themselves. This study provides the first analysis of the extensive effects of OWFs and ships on Loons on a large spatial scale. The results provide an essential baseline for future marine spatial planning processes in the German North Sea and elsewhere.

Climate variability and trends in climate extremes in the priority conservation area El Tokio and adjacent areas in northeastern Mexico

El Tokio, a priority conservation area in Mexico and North America, and its adjacent areas hold the world's last remaining colonies of the Mexican Black-tailed Prairie Dog (Cynomys mexicanus) and serve as home to over 250 bird species, including global wintering grassland birds of high conservation concern, and other rare, endemic and endangered species of flora and fauna. While alarming changes in distribution and migration patterns of species existing in the study area have been reported, studies on the role of climate in these changes are scarce, partly because of the lack of climate information. To fill this gap, this study defined the climate types and eight bioclimatic variables of five ecoregions within and adjacent to El Tokio and analyzed climate indices showing trends of climate extremes, using 30-year climate data and the software RClimDex 1.0 RCs. Results showed climate variability in the study area, with 14 climate types, mostly arid and semi-arid. The analysis of bioclimatic variables showed that the Plains of Zacatecano-Potosino Plateau ecoregion, which contains prairie dog colonies, had the highest annual and mean temperature in the most humid, driest and hottest trimesters of the year; its precipitation had lower seasonality in relation to other ecoregions. Climate indices to detect trends in climate extremes showed greater intensity in precipitation, but also longer dry intervals during the year in the Plains of Zacatecano-Potosno Plateau, while the adjacent Sierra with Forests ecoregion, which borders some colonies, showed trends of warmer winters, summers with fewer days with high minimum temperatures, and precipitation that was less in amount and intensity. The generated climate datasets and analyses contribute essential input for climate change studies and for biological studies and conservation programs for the species and ecosystems present in the biologically rich study area, some of which are greatly threatened and of international concern.

Density and Spatial Distribution of Nests of Ectatomma ruidum and Pheidole fallax (Hymenoptera: Formicidae), as Response to the Recovery of Coal Mine Areas

In this study, the spatial pattern of two ant species of different feeding habits, Ectatomma ruidum and Pheidole fallax (Hymenoptera: Formicidae) was assessed in rehabilitated areas of “Cerrejón” coal mine (Colombia). We tested whether there is a relationship between spatial distribution pattern, age rehabilitation and temporal changes. Three sites with different ages of rehabilitation (1, 9 and 20 years) and a secondary forest were sampled during dry and rainy seasons. Within four plots (6 x 40m) per site, we located, counted and estimated the minimum distance among nests. Our results indicated that the number of active nests varied according to sites and sampling season, E. ruidum had the highest density at both seasons, 166 nests ha-1 (forest) and 1333 nests ha-1 (9-y site). The nest density for P. fallax ranged between 125 and 625 nests ha-1 in the forest and the 20-y site, respectively, and at 1-year site ants were absent. Our results indicated that the nest distribution strongly depended on the scale of observation. A uniform distribution pattern was also found, mainly at the local scale (plot level), while an aggregated and random distribution was found at the site level. We conclude that ant density responded mostly to seasonal changes (dry versus wet season).

Distribution Patterns and Long-Term Changes in Vascular Plants of Non-Littoral Areas in the SW Archipelago of Finland. Part IV. Rosaceae, Fabaceae, Onagraceae, Sapindaceae, Oxalidaceae, Geraniaceae, Polygalaceae, Cornaceae, Apiaceae, Rhamnaceae, Rubiaceae

Historical (mainly 1930s) and contemporary records of 482 vascular plant species or genera of non-littoral areas of 464 islands in the archipelago of SW Finland are compared, to visualise changes in distribution patterns, and to identify environmental variables that affect the distribution of the species. The environmental variables were measured in a GIS. Logistic regression analysis was used to find variables that affect the probability of species occurrences. Results, with distribution maps, are presented for each species. The families Rosaceae, Fabaceae, Onagraceae, Sapindaceae, Oxalidaceae, Geraniaceae, Polygalaceae, Cornaceae, Apiaceae, Rhamnaceae and Rubiaceae are presented in this fourth part of the series. A synthesis of the study will be presented in the last part of this article series.

Distribution Patterns and Long-Term Changes in Vascular Plants of Non-Littoral Areas in the SW Archipelago of Finland. Part V. Apocynaceae, Gentianaceae, Menyanthaceae, Oleaceae, Caprifoliaceae, Adoxaceae, Convolvulaceae, Boraginaceae, Lamiaceae, Plantaginaceae, Solanaceae, Scrophulariaceae, Campanulaceae, Asteraceae

Historical (mainly 1930s) and contemporary records of 482 vascular plant species or genera of non-littoral areas of 464 islands in the archipelago of SW Finland are compared, to visualise changes in distribution patterns, and to identify environmental variables that affect the distribution of the species. The environmental variables were measured in a GIS. Logistic regression analysis was used to find variables that affect the probability of species occurrences. Results, with distribution maps, are presented for each species. The families Apocynaceae, Gentianaceae, Menyanthaceae, Oleaceae, Adoxaceae, Caprifoliaceae, Convolvulaceae, Boraginaceae, Lamiaceae, Plantaginaceae, Solanaceae, Scrophulariaceae, Campanulaceae and Asteraceae are presented in this fifth part of the series. A synthesis of the study will be presented in the last part of this article series.

Postmortem T2*- Weighted MRI Imaging of Cortical Iron Reflects Severity of Alzheimer's Disease.

The value of iron-based MRI changes for the diagnosis and staging of Alzheimer’s disease (AD) depends on an association between cortical iron accumulation and AD pathology. Therefore, this study determined the cortical distribution pattern of MRI contrast changes in cortical regions selected based on the known distribution pattern of tau pathology and investigated whether MRI contrast changes reflect the underlying AD pathology in the different lobes. T2*-weighted MRI was performed on postmortem cortical tissue of controls, late-onset AD (LOAD), and early-onset AD (EOAD) followed by histology and correlation analyses. Combining ex vivo high-resolution MRI and histopathology revealed that: 1) LOAD and EOAD have a different distribution pattern of AD pathological hallmarks and MRI contrast changes over the cortex, with EOAD showing more severe MRI changes; 2) per lobe, severity of AD pathological hallmarks correlates with iron accumulation, and hence with MRI. Therefore, iron-sensitive MRI sequences allow detection of the cortical distribution pattern of AD pathology ex vivo.

The influence of paleo-bathymetry on total organic carbon distribution tested in the Cretaceous Hammerfest Basin, Barents Sea

Abstract In basin modelling and petroleum system analysis geometries during deposition of sediments (paleo-water depth) and distribution of organic matter are initial parameters used for further interpretation or modelling. This paper presents an approach, combining backstripping with a probabilistic forward sedimentary model to calibrate paleo-water depth (PWD). The stochastic PWD results serve as an input for organic facies models and the study demonstrates how PWD will influence models for total organic carbon distribution in a sedimentary basin. For the Early Cretaceous Hammerfest Basin, mainly shelfal to upper bathyal bathymetries (average PWD values vary between 118 and 318 m) result in average total organic carbon (TOC) varying between 0.47 and 5.24 wt% across the basin. For the different models basin averaged TOC values are similar but vertical and lateral distribution pattern change significantly, especially towards the shallow end-member PWD. The results indicate that PWD uncertainties propagate non-linearly into source rock distributions.

The effects of fish feeding by visitors on reef fish in a Marine Protected Area open to tourism

Abstract: Coral reef-based tourism has risen sharply across the globe, coupled with an increase in fish feeding by visitors. Studies indicate that fish feeding is one of the leading causes of changes in distribution patterns, abundance, the structure of marine fish communities, and fish behavior. The aim of this study was to determine the effect of human presence and fish feeding on the behavior of reef fish by conducting in situ experiments in tide pools in a Marine Protected Area located at the northern limit of the Abrolhos Bank in the South Atlantic Ocean. Eight feeding sessions were conducted and filmed, resulting in a total of 160 minutes of video footage. Each filming session recorded four different experimental conditions alternating between human presence, human absence, and fish feeding. Our findings suggest that fish feeding may cause changes in fish behavior, such as habituation to human presence, conditioning to fish feeding, increased aggressiveness, attacks on humans, and short-term changes in species distribution. The continuation of fish feeding over time can cause an increase in the size of the populations of species that consume food provided during feeding and consequently trigger changes in the structure of communities.

Modic Changes in the Lumbar Spine are Common Aging-related Degenerative Findings that Parallel With Disk Degeneration.

This is a cross-sectional study. To determine the prevalence and distribution patterns of Modic changes (MCs) in the lumbar spine and their associations with disk degeneration in mainland Chinese using a sample of general population. Previous studies reported that the prevalence of MCs in Hong Kong Chinese was much lower than in other populations. Moreover, their associations with disk degeneration need further study. The study sample consisted of 442 subjects (53.6±14.9 y; range, 20-88 y) randomly selected from a typical Chinese community. Lumbar spines were imaged using a 3.0 T magnetic resonance scanner. Eleven endplates (L1-S1) in the lumbar spine were evaluated for the presence of MCs, type, location, and size to determine MCs prevalence and distribution patterns. Disk degeneration was graded using a Pfirrmann scale. MCs were present in 209 (47.3%) subjects and 593 (12.2%) endplates. Among these endplates, 84.1% (499) were type II, 9.1% (54) were type I, and 6.4% (38) were mixed MCs. Approximately 2/3 MCs were present in the lower lumbar spine and 44.9% of MCs were at the L5/S1 disk level. Most MCs (73.9%) involved both endplates of a disk. Greater age [odds ratio (OR)=2.44 for each 10-year increase, P<0.001] and body mass index (OR=1.07, P=0.016) were associated with the presence of MCs, as was adjacent disk degeneration (OR=6.00, P<0.001), controlling for age and other covariates. Greater age, body mass index, and adjacent disk degeneration were also associated with greater MCs size. MCs are common in mainland Chinese, with type II predominating. MCs mainly present in the lower lumbar region and tend to occur in pairs. MCs were strongly associated with age and disk degeneration, suggesting MCs may be aging-related degenerative findings that parallel disk degeneration. Level II.

Discontinuities in soil strength contribute to destabilization of nutrient-enriched creeks.

In a whole-ecosystem, nutrient addition experiment in the Plum Island Sound Estuary (Massachusetts), we tested the effects of nitrogen enrichment on the carbon and nitrogen contents, respiration, and strength of marsh soils. We measured soil shear strength within and across vegetation zones. We found significantly higher soil percent organic matter, carbon, and nitrogen in the long-term enriched marshes and higher soil respiration rates with longer duration of enrichment. The soil strength was similar in magnitude across depths and vegetation zones in the reference creeks, but showed signs of significant nutrient-mediated alteration in enriched creeks where shear strength at rooting depths of the low marsh–high marsh interface zone was significantly lower than at the sub-rooting depths or in the creek bank vegetation zone. To more closely examine the soil strength of the rooting (10–30 cm) and sub-rooting (40–60 cm) depths in the interface and creek bank vegetation zones, we calculated a vertical shear strength differential between these depths. We found significantly lower differentials in shear strength (rooting depth < sub-rooting depths) in the enriched creeks and in the interface zones. The discontinuities in the vertical and horizontal shear strength across the enriched marshes may contribute to observed fracturing and slumping occurring in the marsh systems. Tide gauge data also showed a pattern of rapid sea level rise for the period of the study, and changes in plant distribution patterns were indicative of increased flooding. Longer exposure times to nutrient-enriched waters and increased hydraulic energy associated with sea level rise may exacerbate creek bank sloughing. Additional research is needed, however, to better understand the interactions of nutrient enrichment and sea level rise on soil shear strength and stability of tidal salt marshes.

Food consumption among income classes and its response to changes in income distribution in rural China

PurposeGiven the fact that the income disparity has become extremely severe in rural China, the purpose of this paper is to examine heterogeneity in food consumption among various income classes and to investigate the impact of changes in income distribution patterns on food demand in rural China.Design/methodology/approachIn this study, the authors partition the households into five income classes according to the distribution of household per capita net income. Using household data drawn from the China Health and Nutrition Survey in 2011, a two-stage demand model is applied to estimate a food demand system for each of the income classes. After obtaining the estimated income elasticities of eight studied food groups for each income class, the authors then examine the responsiveness of food demand to the changes in income distribution by means of four scenarios with varying income distribution.FindingsThe empirical results indicate that substantial differences in food consumption exist across various income classes. Specifically, the lowest-income households are more sensitive to price and income changes for most studied food groups than the highest-income households are. In general, income responsiveness is higher for meats, aquatic products and dairy products. Based on estimated income elasticities, the projected food consumption under different income distribution patterns shows that changes in income distribution have significant influences on food consumption. In addition, the authors conclude that a more equal distribution of income would be associated with a higher demand for food in rural China.Originality/valueThis paper employs a two-stage demand model to estimate food demand in rural China by income classes. The results imply substantial differences in food demand for various income classes. Therefore, income distribution should be taken into account instead of an average estimation for the population as a whole when investigating food demand in rural China. Given the significant changes in income distribution in rural China, this study provides several important policy implications to alleviate income inequality and poverty, as well as to improve nutrition for lower-income classes.

Modeling Large Carnivore and Ranch Attribute Effects on Livestock Predation and Nonlethal Losses

Predator-livestock interactions are a major concern for both agriculture and conservation globally. Using retrospective survey data from 274 ranches in Wyoming, United States, we used information theory to model how ranch attributes and large carnivores influenced the timing, duration, and severity of livestock predation. We then used constrained ordination to understand how 1) landscape, weather, and animal features influence predation and 2) how livestock behavior and nonlethal loss relate to ranch attributes and large carnivores. Timing, duration, and severity of livestock predation were generally not explained by ranch size or number of counties but were explained by livestock type, livestock parturition (either timing or duration), and documented large carnivore loss. Addition of the large carnivore loss variable to global models always improved Akaike information criterion scores. Rangelands characterized as rough, forested, shrubby, or a public grazing allotment reportedly increased predation risk, in part, due to large carnivore exposure. Approximately two-thirds of participants noticed livestock nervousness if a predator was nearby, half of participants noted changes in livestock distribution patterns, and a quarter of participants noted a reduction in livestock grazing time. Nonlethal losses such as lower weight gains, lower conception rates, lower birth rates, and delayed birth season were reported by 27%, 19%, 12%, and 11% of participants, respectively. Ordination revealed separation between behavioral changes and nonlethal losses, attributed to large carnivore exposure. Parturition relative to livestock type was also strongly correlated to timing and duration of predation for cattle-only operations but not for operations with sheep. The predictive cattle predation-parturition model suggests that for each additional month of calving, producers should anticipate 21 additional d of predation. Understanding predator-livestock interactions relative to ranch and rangeland features, parturition, large carnivore exposure, and losses that extend beyond mortalities can assist in developing novel strategies to mitigate lethal and nonlethal losses.

Effect of pore structure on displacement efficiency and oil-cluster morphology by using micro computed tomography (μCT) technique

Low recovery in mature oil fields, mostly in a high-water-cut stage, requires advanced methods to enhance oil recovery. However, incomplete understanding of the mechanisms of low oil recovery in pore-scale limits the application of proposed methods in industry. Digital core technology and high-resolution micro computed tomography (μ CT) scanning were deployed to investigate effects of pore structure and permeability scales on oil displacement efficiency and remaining oil-cluster morphology visually and quantitatively. In the study, brine displacing oil experiments were conducted on four naturally water-wet sandstone samples with different permeability scales. A μCT equipment with a resolution of 3.78 μm was used to image the samples at different water flooding stages by injecting brine water with different PV (pore volume): 0 (irreducible water saturation), 1, 5, 15, and 50PV. The complexity of the pore structures of four samples were quantified by fractal dimension analysis from μCT images. The order of pore structure from simple to complex is samples 1, 2, 3, and 4. Then the distributions of cluster pattern of reminding oil were analyzed. Based on the cluster pattern distributions, microscopic remaining oil was classified into five categories by using shape factor and Euler number. Results show that large connected oil clusters can be more easily broken into smaller segments in high permeability samples. Sample 1 has the largest pore connectivity and shows the biggest change of distribution pattern. The clusters are concentrated on one to two distribution patterns. If the permeability gets lower and pore structure becomes complex, all distribution patterns coexist. Also, the lower permeability samples show a smaller displacement efficiency at all displacing stages. A large coordination number improves the displacement efficiency, but the large tortuosity and pore-throat ratio reduce the displacement efficiency. Results of this study can enrich the understandings of the low oil recovery and can inspire innovative methods to further tap those remaining oil.

Scaling distributional patterns of butterflies across multiple scales: Impact of range history and habitat type

AbstractAimAssessing the threat status of declining but yet widespread species poses a challenge to applied ecologists. Previous studies using a common metric to describe the spatial aggregation of occurrences across multiple scales, the fractal dimension Dij, have suggested that species’ distributional trends may be deduced from readily understandable spatial patterns: Expanding species are expected to show more aggregated spatial distributions (higher value of Dij) than declining species (lower value of Dij). Here, we revisited these predictions using a large‐scale empirical dataset on Finnish butterflies.LocationFinland.MethodsFor each butterfly species (n = 97) and across three spatial scales (grid squares of 10 km, 50 km and 100 km), we calculated the area of occupancy (AOOi) as the sum of occupied grid squares. We employed values of AOOi to derive the Dij for each butterfly species. We then used these metrics to compare the changes in spatial patterns of distribution (∆AOOi and ∆Dij) between two time periods, 2000–2002 and 2009–2011.ResultsMajority of the studied butterfly species showed declining areas of occupancy (at the scale of 10 km, ∆AOO10) and fractal dimensions (across the scales from 10 km to 100 km, ∆D10–100) between the two study periods. In contrast to predictions, AOO10 and D10–100 showed negative impacts on the ∆AOO10, an observation that may be explained by the high proportion of declining species in our data. Butterfly species with the greatest fractal dimensions at regional scales (D10–100) in the years 2000–2002 showed both positive long‐term distributional trends and most notable northern recent range limit shifts.Main conclusionsOur results were in most cases congruent with the prediction of higher fractal dimension values in expanding compared to declining species. As a novel observation, many butterflies expanded northwards in spite of their occurrences getting simultaneously more scattered, particularly in southern Finland.

Behavior of Trip Length Distribution Pattern due to the Variation of Trip Length Interval Determination

Transport Model is always needed and important for developing Transportation System Master Plan. Trip Distribution is one of the important parts of Transport Model, which is a result mathematical operation of trip generation and deterrence function. Trip Length Distribution Pattern is the foundation of Deterrence Function. The trip length distribution pattern can change due to the various trip length interval used. Analog to this, the Deterrence Function can also change. The research result indicate that the distribution pattern change significantly on trip length interval 1 to 3 km. For trip length interval of 4 to 8 km, the trip length distribution indicate the general characteristic of trip length distribution, i.e. the number of trips is high in short distance and getting down in the longer trip distance. The trip interval of 7 km gives the most accepted Tanner Deterrence Function .

Behavior of Trip Length Distribution Pattern due to the Variation of Trip Length Interval Determination

Transport Model is always needed and important for developing Transportation System Master Plan. Trip Distribution is one of the important parts of Transport Model, which is a result mathematical operation of trip generation and deterrence function. Trip Length Distribution Pattern is the foundation of Deterrence Function. The trip length distribution pattern can change due to the various trip length interval used. Analog to this, the Deterrence Function can also change. The research result indicate that the distribution pattern change significantly on trip length interval 1 to 3 km. For trip length interval of 4 to 8 km, the trip length distribution indicate the general characteristic of trip length distribution, i.e. the number of trips is high in short distance and getting down in the longer trip distance. The trip interval of 7 km gives the most accepted Tanner Deterrence Function .

Distribution patterns of settlement-stage juveniles of Girella punctata and Girella leonina on the rocky coast of the Kanto\u2013Izu region, Japan

The early life history of girellid fishes in Japanese waters is unclear, and little is known about their species-specific reproductive strategies. We examined seasonal changes of distribution patterns for settlement-stage juveniles of Girella punctata and Girella leonina on the rocky shore in the regions of Kanto and Izu, Japan, to infer the influence of the Kuroshio Current on their reproduction. We collected 813 settlement-stage juveniles mainly in Sagami Bay and genetically identified the species. The juveniles of G. punctata were collected on the rocky shore in Sagami Bay during April to August, with the abundant catch in May and June. Thus, we infer that juvenile G. punctata ubiquitously inhabit the rocky shore in the area in spring and summer. By contrast, juveniles of G. leonina were rarely collected in Sagami Bay, with a total catch of only 66. Notably, no juveniles were collected during the wintertime in Sagami Bay, although an abundant catch of G. leonina had been previously reported for Sagami Nada off Sagami Bay during January to March. This clear-cut difference between the areas likely reflects the difference in proximity to the path of the Kuroshio Current. We expect that the Kuroshio Current strongly influences the reproductive success of G. leonina.