Gunma Prefectural Fisheries Experimental Station

Three-dimensional (3D) documentation is increasingly being utilized in forensic investigations to record injuries and reconstruct crime scenes accurately. Although photogrammetry offers a low-cost and accessible method for capturing surface details, its integration with postmortem CT (PMCT) data and virtual reality (VR) can further enhance spatial understanding. We report a fatal case of a stair-related fall of a man in his 70s, in which we visualized the injuries by combining PMCT data with surface models of the body and the staircase. A 3D model of the bones was created from the PMCT data, whereas surface models of the body and staircase were generated using photogrammetry. The reconstructed scene was visualized in VR using a MetaQuest 3 headset. The reconstructed scene clearly demonstrated the spatial relationship between the stair edges and injury sites, such as the occipital region, midthoracic spine, and sacrum. The vertical distances between the injuries closely matched the staircase step depth, supporting the interpretation of stair-related falls. This method provides an intuitive and immersive understanding of injury mechanisms. Our approach demonstrates the feasibility and utility of integrating CT, photogrammetry, and VR in forensic death investigations, offering enhanced documentation and visualization that can benefit not only forensic experts but also legal professionals and juries.

ABSTRACTCatch‐and‐release (C&R) angling is becoming more common worldwide for managing stream‐resident salmonids but has only recently been introduced in Japan. However, few studies have examined effects of C&R regulations on fish populations through adequate experimental designs. We estimated effects of implementing a C&R regulation on stream‐resident salmonids. The western part of the Agatsuma River system in Japan is a fishing area with standard regulations under which anglers can harvest white‐spotted charr or masu salmon of > 15 cm total length. In contrast, the eastern part is a fishing area with a C&R regulation requiring release of all caught fish, owing to radiocesium contamination caused by a nuclear accident at Fukushima. Density and total length of stream‐resident salmonids were examined in these areas in several tributaries. Fish density was significantly higher in the C&R area, whereas total length did not differ significantly between areas. Implementing a C&R regulation may be effective for conserving salmonid populations in mountainous streams.

Abstract Habitat fragmentation is a pervasive threat to biodiversity. Linearly arranged habitats such as stream networks are particularly vulnerable to fragmentation. As the landscape becomes increasingly human dominated, conservation values of fragmented habitat patches cannot be overlooked. It is critical to understand the demographic mechanisms of population persistence or extirpation in fragmented patches. We studied dynamics of spatially structured populations of two Japanese landlocked salmonids persisting for >30 years in a headwater stream network that is highly fragmented due to low‐head dams in the mainstem. We parameterised and analysed spatial matrix population models using 9‐year mark–recapture data. Tributaries supported higher survival rates in some life stages, and movement was asymmetrical from the tributaries to the mainstem. Accordingly, population growth rates were higher in the tributary patches than the mainstem in both species despite the tributaries occupying only 12% or 18% of the study stream network by surface area. The tributaries harboured more physically and hydraulically complex instream habitats (i.e. higher wood density and flow refugia), indicating that habitat patch quality was more important than habitat patch size in determining the dynamics of these spatially structured populations. Tributary locations in the stream network were important in the trajectory of these populations. The upstream‐dwelling charr persisted in the highly fragmented mainstem patch (i.e. six impassable infrastructures in a <500 m patch) due to immigration of fish from upstream including the tributary. However, the downstream‐dwelling salmon has been gradually extirpated from the uppermost section of the fragmented mainstem patch because they could not maintain a positive population growth rate after loss of emigrants was accounted for and immigration was prevented due to fragmentation. Synthesis and applications. We conclude that small tributaries have rescued the spatially structured populations from extirpation (charr) or at least slowed down extirpation (salmon). Legal protection of headwaters as aquatic habitats is weak globally. Our results suggest that stream management plans underestimating the demographic value of small tributaries will likely fail to conserve populations of headwater inhabitants and therefore endanger aquatic biodiversity. We discuss conservation implications of this study related to habitat connectivity and fisheries management.

Radiocesium concentrations were measured in the pectoralis muscles of great cormorant (n = 36) collected from Gunma Prefecture between November 2011 and July 2012. The 137Cs contamination levels in great cormorant were consistent with the 137Cs deposition levels on ground soil and 137Cs concentrations in freshwater fishes. The Tag of great cormorants were comparable with those of other birds except for copper pheasant.

In the case of a fire incident such as arson, the combustion experiment that reconstructed the fire scene will be conducted to clarify the facts. However, various problems such as construction costs and securing an experimental environment must be dealt with. Therefore, the purpose of this study is to utilize fire simulation for the investigation of fire incidents. In this study, combustion experiments and FDS (Fire Dynamics Simulator) simulations assuming gasoline arson in the kitchen, which have not been reported so far, were conducted and compared. Next, the observation of fire damage using the accumulated heat-flux was evaluated by a newly developed analysis tool for visual evaluation. The simulation results such as burning behavior, temperature changes, and the burned away phenomenon of the door showed good agreement with those experimental results. Burning behavior in the kitchen, that couldn't be observed in the combustion experiment were grasped in detail in the simulation. Furthermore, the relationship between the fire source and the fire damage on the floor, which couldn't be explained only by the observation results after extinguishing the fire, could be reasonably explained by the visual evaluation of burning behavior and the accumulated heat-flux in the kitchen by using the simulation. Therefore, the fire simulation was shown to be an effective tool for analyzing fire phenomena.

Abstract The main purpose of this study was to find the optimal cochineal dye concentration and treatment time for marking Japanese smelt (also known as Wakasagi) Hypomesus nipponensis, more specifically their eggs, by understanding the mechanisms that determine survival rates and mark quality. Eggs were immersed in a range of cochineal dye concentrations (40–100 g/L) at varying intervals (6–72 h). Following that, mark quality was evaluated according to fluorescence intensity by examining the marked otolith of the larvae. The statistical model selection indicated that the interaction between the cochineal dye concentrations and immersion intervals (g/L × h) had a negative effect on survival such that at low concentrations survival decreased with increasing immersion time but at high concentrations survival was relatively low at all of the immersion times. On the other hand, the results of evaluating the marked otoliths indicated that mark quality improved with increases in concentration and immersion time individually. These results suggest that there is a trade‐off between mark quality and survival of Japanese smelt when using a cochineal dye solution. Combining the results of the survival rate and mark‐quality experiments, the cochineal dye marking conditions with both high survival rates and high fluorescence intensity are 60 g/L for 24 h, 40 g/L for 48 h, and 40 g/L for 36 h.

Related interleukin-2, -15, and -15-like (IL-2, -15, and -15L) are ancient cytokines, with all three genes surviving in extant fish and some mammals. The present study is the first to identify IL-15L functions, namely in rainbow trout. In isolated trout splenocytes, and in vivo, purified recombinant IL-15L+IL-15Rα molecules induced expression of IL-4 and IL-13 homologs, which are markers of type 2 immunity. In contrast, trout IL-15 stimulated type 1 immunity markers, thus IL-15 and IL-15L can have opposing functions. Trout IL-15L was more dependent on “in trans” presentation by the receptor chain IL-15Rα than IL-15, and stimulated CD4−CD8−(IgM−) lymphocytes from thymus and spleen. We propose an important role for IL-15L early in the type 2 immunity cytokine cascade. Trout IL-2 and IL-15 exhibited features reminiscent of their mechanistic and functional dichotomy observed in mammals; for example, IL-15 but not IL-2 required a receptor alpha chain (only IL-15Rα in the case of fish) for its stability, and only IL-15 was efficient in stimulating lymphocytes from mucosal tissues. Data suggest that IL-15L and IL-15 may be particularly effective in stimulating innate lymphocyte type 2 cells (ILC2) and natural killer (NK) cells, respectively, but further identification of the cell types is needed. An interesting finding different from in mammals was the efficient stimulation of CD4+CD8+ thymocytes by IL-2. In short, this study presents fundamental information on the evolution of the IL-2/15/15L cytokine family.