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Alabama (AL) is a hotspot in the Gulf of Mexico (GoM) for human interaction–related cetacean strandings, including harassment, vessel strikes, and fisheries interactions. We examined four bottlenose dolphins (Tursiops truncatus) stranded dead along the AL coast during 2012–2017 with severed peduncles suspected to be related to human interaction (HI). Evidence from each case, including photographs, gross necropsy results, and histopathologic findings when available, was reviewed to determine the mode of severance and whether it contributed to death. In each case, the severance site had smooth, clean edges on at least one side, indicating the use of a sharp instrument to remove the caudal peduncle and flukes. Three cases also had evidence of fisheries interactions, including linear impressions around the rostrum, fins and/or flukes, indicating that these animals may have been entangled in fisheries gear prior to death. Histopathology in one of these cases revealed that the severance occurred perimortem; speculatively, the caudal peduncle and flukes may have been cut off to facilitate removing the dolphin from its entanglement. Although cases of amputation and mutilation are not uncommon globally among stranding reports, few cases have been described and analyzed in the literature. This paper is the first to document and compare multiple cases of severed peduncles with evidence of HI, including fisheries, in the GoM. This case series enhances our understanding of the types of HI occurring in bottlenose dolphins and highlights the need for continued public education, policy, and management to address cases like these. [ABSTRACT FROM AUTHOR]

Simple Summary: Within cells, there are numerous compartments called 'organelles' that perform a range of specialised functions required to support life. Organelles are constantly adapting to their environment, changing shape and cooperating with each other depending on the cellular needs, which is essential for cell health as defects in these processes lead to human diseases. One example of organelle dynamic behaviour is the formation of thin tubules that extend and retract from the membranes that delimit the organelles. With a focus on two organelles (peroxisomes and mitochondria) that have roles in cell metabolism and protection, we examine how and why these membrane extensions form, and what their function is within the cell. This includes forming new organelles or organelle networks; increasing the organelle surface area to maximise uptake of molecules; mediating communication between different organelles. We propose that these membrane extensions allow organelles to 'reach out' and explore their surroundings more efficiently. Together, this review highlights the importance of organelle dynamics, and specifically membrane extension, in maintaining healthy cell function, as well as exploring the questions remaining to be answered to further our understanding of this essential aspect of cell biology. Organelles within eukaryotic cells are not isolated static compartments, instead being morphologically diverse and highly dynamic in order to respond to cellular needs and carry out their diverse and cooperative functions. One phenomenon exemplifying this plasticity, and increasingly gaining attention, is the extension and retraction of thin tubules from organelle membranes. While these protrusions have been observed in morphological studies for decades, their formation, properties and functions are only beginning to be understood. In this review, we provide an overview of what is known and still to be discovered about organelle membrane protrusions in mammalian cells, focusing on the best-characterised examples of these membrane extensions arising from peroxisomes (ubiquitous organelles involved in lipid metabolism and reactive oxygen species homeostasis) and mitochondria. We summarise the current knowledge on the diversity of peroxisomal/mitochondrial membrane extensions, as well as the molecular mechanisms by which they extend and retract, necessitating dynamic membrane remodelling, pulling forces and lipid flow. We also propose broad cellular functions for these membrane extensions in inter-organelle communication, organelle biogenesis, metabolism and protection, and finally present a mathematical model that suggests that extending protrusions is the most efficient way for an organelle to explore its surroundings. [ABSTRACT FROM AUTHOR]

Predation of fish on their scyphozoan hosts has not been clearly defined using analysis of gut contents because gelatinous prey are difficult to visually detect and are dissolved by fixative solutions. Therefore, scyphomedusae have been generally considered not relevant in fish diet. To determine the contribution of their scyphozoan host tissue to the assimilated diet of age-0 Chloroscombrus chrysurus, we determined δ[sup.13]C and δ[sup.15]N of fish, their hosts (scyphomedusae Aurelia sp. and Drymonema larsoni) and their potential prey--small plankton (200 µm)--in the coastal waters of Alabama, USA. The diet of C. chrysurus was defined using the Bayesian mixing model Stable Isotope Analysis in R (SIAR). Models indicated that the scyphozoan hosts contributed on average ~90 % to fish assimilated diet. In contrast with previous dietary assessments based on analysis of gut contents, these results highlight that scyphozoans are important to the diet of fish associated with them. Because several ecologically and economically important fish species live in association with scyphomedusae, a redefinition of trophic links in marine food webs may be needed in light of the findings in this study., Introduction Interactions between fish and jellyfish (Phylum Cnidaria, Class Scyphozoa) are complex. Jellyfish can consume fish eggs and larvae, and they potentially compete with fish for plankton prey (reviewed in [...]

Application of stable isotope analysis (SIA) in jellyfish allows definition of trophic patterns not detectable using gut content analysis alone, but analytical protocols require standardization to avoid bias in interpreting isotopic data. We determined [delta][sup.13]C and [delta][sup.15]N in Aurelia sp. from the northern Gulf of Mexico (30[degrees]00'N, 89[degrees]00'W-30[degrees]24'N, 88[degrees]00'W) to define differences in stable isotope composition between body parts and whole body, the effect of lipid extraction on [delta][sup.13]C in tissues, and fractionation values from medusa to prey. The isotopic composition of bell and whole Aurelia sp. was not different. The increase in [delta][sup.13]C values after lipid removal suggested a correction is needed. To aid future analyses, we derived a correction equation from empirical data for jellyfish samples. Laboratory feeding experiments indicated medusae increased +4 %0 in [delta][sup.13]C and +0.1 [per thousand] in [delta][sup.15]N compared to their diet. These results suggest protocols commonly applied for other species may be inaccurate to define Aurelia sp. trophic ecology. Because Aurelia spp. are commonly found in marine ecosystems, accurately defining their trophic role by use of SIA has implications for understanding marine food webs worldwide., Introduction Despite their potential importance within marine food webs, the trophic position of jellyfish is not well defined (Pauly et al. 2009). In part, understanding jellyfish trophic ecology is difficult [...]