Search Results (189)

This paper investigates the cultural, spiritual, and ecological use and value of fish by-products in the material practices of Alaska Native (Indigenous Peoples are the descendants of the populations who inhabited a geographical region at the time of colonisation and who retain some or all of their own social, economic, cultural, and political institutions. In this paper, I use the terms “Indigenous” and “Native” interchangeably. In some countries, one of these terms may be favoured over the other.) and Greenlandic Inuit women. It aims to uncover how fish remnants—skins, bones, bladders, vertebrae, and otoliths—were transformed through tanning, dyeing, and sewing into garments, containers, tools, oils, glues, and adornments, reflecting sustainable systems of knowledge production rooted in Arctic Indigenous lifeways. Drawing on interdisciplinary methods combining Indigenist research, ethnographic records, and sustainability studies, the research contextualises these practices within broader environmental, spiritual, and social frameworks. The findings demonstrate that fish-based technologies were not merely utilitarian but also carried symbolic meanings, linking wearers to ancestral spirits, animal kin, and the marine environment. These traditions persisted even after European contact and the introduction of glass trade beads, reflecting continuity and cultural adaptability. The paper contributes to academic discourse on Indigenous innovation and environmental humanities by offering a culturally grounded model of zero-waste practice and reciprocal ecology. It argues that such ancestral technologies are directly relevant to contemporary sustainability debates in fashion and material design. By documenting these underexamined histories, the study provides valuable insight into Indigenous resilience and offers a critical framework for integrating Indigenous knowledge systems into current sustainability practices. Full article

Gray snapper (Lutjanus griseus; Family: Lutjanidae) local habitat preferences have been assessed, but the biotic and abiotic factors influencing age and growth rates in Mosquito Lagoon, Florida, have not been quantified. To address this knowledge gap, the goal of this study was to estimate mean age and growth rate of gray snapper, and use generalized linear mixed models to investigate if prey and/or other environmental factors (e.g., abiotic/biotic conditions, time, location, or habitat restoration status) impact size at both the lagoon- and habitat-specific scales. Age data were extracted via otolith microstructural analyses, and incorporated with size into a lagoon-scale linear growth model. Based on microstructural analyses, mean age of gray snapper at the lagoon scale was 175 ± 66 days (range = 56–350 days). The results indicate the most common life stage of gray snapper in Mosquito Lagoon is juveniles, with living shoreline habitats having a greater proportion of relatively young juveniles (111 ± 36 days) and oyster reef habitats having a greater proportion of relatively older juveniles (198 ± 58 days). The estimated growth rate was 0.43 mm/day. Body mass and body length were correlated positively with habitat quality and lagged salinity levels. Hence future studies should strive to characterize benthic habitat characteristics, and investigate biotic and abiotic factors that potentially influence gray snapper growth. Collectively, this study increases our understanding of environmental drivers affecting juvenile gray snapper development and shows that the restoration of benthic habitats can produce conditions conducive to gray snapper growth. The age-, size-, and habitat-specific growth rates of juveniles from this study can be incorporated into stock assessments, and thereby be used to refine and develop more effective ecosystem-based management strategies for gray snapper fisheries. Full article

Silurus lanzhouensis is a large-sized commercial fish species endemic to the mid-upper reaches of the Yellow River, serving as a “Card of Aquatic Biological Species in the Yellow River”. However, due to factors such as overfishing and habitat changes, it has been listed as an endangered species. In order to protect and restore its wild resources, we conducted a detailed study for the first time from 2022 to 2024 on the age composition, growth characteristics, mortality rate, and current status of resource exploitation of the S. lanzhouensis population in the upper Yellow River. A total of 489 individuals underwent measurements for their total length (L) and body weight (W), with age determination conducted using lapillus otoliths. The collected samples exhibited a spectrum of total lengths spanning from 2.5 to 63.7 cm, body weights ranging from 0.11 to 1974.15 g, and ages ranging from 1 to 6 years. Further analysis of the length–weight relationships unveiled an allometric growth index (b) of 2.9562 for the overall samples, indicating an isometric growth pattern. Additionally, insights into the growth characteristics of S. lanzhouensis were provided by the von Bertalanffy growth function, revealing an asymptotic total length (L_∞) of 119.30 cm and a growth coefficient (K) of 0.1278 yr⁻¹. The growth characteristic index (φ) totaled 3.2598, suggesting a moderate growth rate in comparison to other Silurus species. The total mortality rate (Z) recorded for the population of S. lanzhouensis was found to be 0.5296 yr⁻¹. Through the application of three distinct methodologies on exhaustive samples, the average natural mortality rate (M) was calculated to be 0.3105 yr⁻¹. Consequently, the fishing mortality rate (F) for the entire sample set was determined to be 0.2191 yr⁻¹, leading to an exploitation rate (E) of 0.4137. Based on the survey findings, it is evident that the population of S. lanzhouensis has not been subjected to over-exploitation, attributable to ongoing stock enhancement. These results also provide foundational data for the protection and restoration of S. lanzhouensis in the upper Yellow River. Full article

The age-based life history of two commercially important parrotfishes (Labridae: tribe Scarinae) and one goatfish (Mullidae) were characterized based on the commercial nearshore fishery in Saipan, Commonwealth of the Northern Mariana Islands. Age, growth, reproduction, and mortality were derived from fishery-dependent samples using sagittal otoliths and gonads for the stareye parrotfish Calotomus carolinus, pacific bullethead parrotfish Chlorurus spilurus, and yellowfin goatfish Mulloidichthys vanicolensis. All three species had short lifespans of 10 years or less, with a maximum age of 4 years for C. carolinus, 10 years for C. spilurus, and 7 years for M. vanicolensis. All three species had a fast initial growth to terminal body sizes, early maturation, and spawned throughout the year. The age-based demographic information presented here can be used to inform future stock assessments, fisheries management, and population models. Full article

The intensification of human activities in recent years has led to significant overexploitation of Triplophysa strauchii populations, resulting in a decline in the species’ natural stocks. This underscores the need for research and development initiatives aimed at supporting the recovery and sustainable management of the species. Therefore, this study investigated its biological traits and isozyme characteristics in detail. First, throutigations of fish ecology, the age and growth patterns of T. strauchii were examined. The results revealed that the length of the otoliths was greater than the width and that the intermajor groove was indistinct. The age range of the fish was 0–4 years. A correlation between body length and weight revealed that T. strauchii exhibited isometric growth patterns. In terms of growth parameters, the inflection point in age for T. strauchii was t_i = 3.23. Additionally, to analyze the enzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), and esterase (EST) in ten tissues of T. strauchii (liver, muscle, heart, gills, eye, brain, fins, kidneys, gonads, and intestines), vertical plate electrophoresis was performed via polyacrylamide gels. The results of isoenzyme analysis revealed that the LDHA (lactate dehydrogenase A subunit) gene was predominant in all tissues. A maximum of two s-MDH enzyme bands with three m-MDH enzyme bands were detected, with a classic enzyme profile and no gene mutation. The EST enzyme was highly expressed in the liver and kidney and was less polymorphic. In general, T. strauchii exhibited a spindle-like body shape and isometric growth patterns in the Turks River. It exhibited a narrow age range, strong adaptability, and stable genetic traits. This species has high development potential, utilization value and ecological significance. Full article

Pakistan’s marine fishing industry is crucial to the country’s economy, generating employment opportunities and foreign revenue. It produces 80% of the country’s total fish production. Otolithes ruber is a commercially important fish on the Makran coast of Pakistan, contributing significantly to the region’s croaker fisheries. This study is the first to apply three length-based approaches for assessing the stock status of O. ruber in the Makran coast: (1) TropFishR to estimate the mortality, growth parameters, and current exploitation status, reference points based on the yield per recruitment model, (2) the length-based Bayesian biomass method (LBB) to calculate stock biomass, and (3) the length-based spawning potential ratio (LBSPR) to estimate the spawning potential ratio. The length–weight relationship of Otolithes ruber was a positive allometric pattern (b = 3.28; R² = 0.94). Growth parameters for Otolithes ruber were L_∞ = 55.47 cm, K = 0.50 year⁻¹. The calculated total mortality rate (Z), natural mortality (M), and fishing mortality (F) were 2.27 year⁻¹, 0.67 year⁻¹, and 1.6 year⁻¹, respectively. The exploitation rate (E) was 0.70, indicating severe overexploitation. The current length at first capture (Lc₅₀) = 27.37 cm was lower than that at first maturity (Lm₅₀) = 30.75 cm, indicating growth overfishing. The current spawning potential ratio (8%) was lower than the optimal value (40%), indicating recruitment overfishing. The current biomass, concerning virgin biomass B/B_o, was also 8%, resulting in a 92% stock decline. We recommend reducing the exploitation pressure by limiting the commercial catch to an optimum length range of 34.5–42.2 cm and reducing fishing pressure by 40% to ensure sustainable fishery management. Full article

Age determination through reading annual rings in whole otoliths is a complicated, time-consuming task that can lead to errors in population age structure, negatively affecting marine fish management plans. Recently, Fourier transform near-infrared spectroscopy (FT-NIRS) has been successfully used to evaluate annual age, at least in several long-life fish species. European anchovy (Engraulis encrasicolus) is an important pelagic species for its ecological role and socioeconomic value. In the Mediterranean Sea, anchovy stocks are regularly monitored for assessment purposes, and fish age is calculated by traditional otolith reading. In the present study, anchovies, caught over a decade (2012 to 2023) during on-board surveys in four different areas (i.e., North Tyrrhenian, South Tyrrhenian, North of Sicily, and Strait of Sicily), provided an otolith collection used to acquire absorption spectra by FT-NIRS. These spectra were processed to optimize calibration models, and the best linear models obtained revealed a good predictability for anchovy annual age (coefficient of determination of 0.90, mean squared error 0.3 years, bias < 0.001 years). The calibration model developed for all regions combined proved more robust than the models for each area, demonstrating its efficacy for the entire study area. FT-NIRS analyses proved suitable for predicting age, when applied to E. encrasicolus individuals within the age range of 0 to 3, also when compared to traditional aging methods. Moreover, this methodology improved the standardization of age estimates. Finally, this preliminary study encourages the further application of FT-NIRS also to short-life pelagic species involved in stock assessment plans. Full article

Background: Benign paroxysmal positional vertigo is the most common cause of dizziness over the lifespan. Management is complicated by both a diagnostic burden (correctly interpreting specific ocular motor findings) and a therapeutic burden (selecting appropriately targeted treatment maneuvers). Purpose: Devise a canalith repositioning maneuver to treat simultaneously benign paroxysmal positional vertigo affecting any combination of semicircular canals on one side. If clinically verified, then this will simplify management. Research design: After analyzing the results of a computer simulator applied to several published maneuvers for treating benign paroxysmal positional vertigo, we used basic principles to design a maneuver that simultaneously, for all three semicircular canals on one side, advances otoliths toward the crus of each canal and prevents retreat toward the ampule of each canal and then tested the maneuver in computer simulation. Study sample: Not applicable. Intervention: Not applicable. Data collection and analysis: Not applicable. Results: We developed a maneuver that computer simulation predicts will successfully treat simultaneously benign paroxysmal positional vertigo affecting any combination of semicircular canals on one side. Conclusions: This maneuver should be tested empirically as a standalone maneuver and compared to other maneuvers. Clinical relevance statement: If the efficacy of this maneuver is clinically verified, then it will simplify management by diminishing the diagnostic burden (of determining affected canals) and treatment burden (of selecting the appropriately targeted maneuvers). Full article

The age, growth and otolith morphometry of Lepidopus caudatus were studied by investigating the sagittal otoliths of specimens collected in the eastern Adriatic. A total of 295 specimens, ranging from 20.7 to 123.0 cm in total length (TL), were analysed. Ground otoliths displayed a typical pattern of opaque and translucent alternated zones. The whole population was dominated by 0⁺-year-old fish, and the maximum observed age was four years. The oldest individuals in the sample were males. The total length-at-age was described by the von Bertalanffy growth model: TL = 134.98[1 − exp (−0.32(t + 1.01))]. Based on the model, we estimated the longevity of the fish, which was 8.35 years. Otolith length, width, thickness and mass were linear with fish TL and age. The most accurate age estimate for the analysed population was derived from the otolith length. Comparisons with available studies from the Mediterranean and other areas are discussed. Full article

This study investigates the age, growth, and mortality of the common pandora (Pagellus erythrinus) in the Central Aegean Sea, providing critical insights into its population dynamics and sustainability. A total of 589 specimens were analyzed, identifying nine age cohorts with mean total lengths ranging from 13.18 cm to 32.94 cm. Growth parameters, estimated using the von Bertalanffy growth model, yielded an asymptotic length (L∞) of 39.53 cm and a growth coefficient (k) of 0.16 year⁻¹, indicating moderate growth rates. The population exhibited non-isomorphic growth (b = 2.49, R² = 98.4), suggesting slower weight gain relative to length. Mortality estimates indicated natural mortality (M) at 0.321 year⁻¹, total mortality (Z) at 0.52 year⁻¹, and fishing mortality (F) at 0.2 year⁻¹, resulting in an exploitation rate (E) of 0.38. The fishing mortality at maximum sustainable yield (FMSY) was estimated at 0.33, with an exploitation rate at MSY (EMSY) of 0.51, suggesting that the population is currently harvested sustainably but close to the threshold of overexploitation. These findings provide essential reference points for fisheries management and highlight the need for continuous monitoring to ensure the long-term sustainability of P. erythrinus in Greek waters. Full article

Otoliths are common in the fossil record and can provide important insight into the evolution and spatial and stratigraphic distribution of fishes, but have remained understudied in many areas of the world. Here, we describe the first marine otolith assemblage from East Africa. The material is from Tanzania Drilling Project cores of late Eocene to early Oligocene age, spanning the Eocene-Oligocene transition (EOT). The assemblage consists of 10 identifiable species of which 5 are new, and 4 remain in open nomenclature. The new species are as follows: Protanago africanus, Bregmaceros tanzaniensis, Ortugobius pandeanus, “Serranus” plasmaticus, and Acanthocepola signanoae. The association of shallow and deep-water taxa along with the dominance of the family Cepolidae, which has not been observed in either the extant or fossil record, makes the faunal composition unusual. However, when taxon occurrences are correlated with stable isotope records from the same cores and compared with previous studies, it is clear the otoliths reflect the sea-level fall known to occur during the EOT, with deeper dwelling taxa in the late Eocene and taxa preferring shallower, which are more shelf-like environments in the early Oligocene. Full article

Background/Objectives: Lower-extremity weakness in older adults is often overlooked, yet it can have reversible or medical causes that contribute to increased falls. Common factors include vision disturbances, impaired balance due to otolith dysfunction, arthritis-related immobility, and lower-extremity neuropathy. This case presents a unique diagnostic challenge in evaluating bilateral lower-extremity weakness and recurrent falls in an older adult, highlighting the complexity of diagnosing conditions with overlapping symptoms. Case Presentation: The patient, a woman with a history of a neuroendocrine tumor, experienced progressive weakness in her lower extremities, along with oculomotor and facial muscle involvement, despite extensive testing. Key clinical findings included elevated protein levels in cerebrospinal fluid, suggesting the possibility of an infectious or autoimmune process. A thorough investigation was conducted, including testing for both common and rare conditions such as Guillain–Barré syndrome, Lyme disease, and tuberculosis. Results: Despite comprehensive diagnostic efforts, no clear etiology was identified. The patient’s condition was eventually considered to be related to carcinomatosis meningoencephalitis, a rare complication from a previous cancer diagnosis. Given the progressive nature of her symptoms and lack of treatment options, she was transitioned to palliative care. Conclusions: This case highlights the importance of a comprehensive differential diagnosis in older patients with unexplained weakness and falls. Rare neurological conditions should not be overlooked, even when more common causes are suspected. Clinicians should remain aware that falls and weakness in older adults may stem from various pathologies, some of which are reversible if identified early, and rare causes must always be considered when standard treatments fail. Full article

This study aimed to investigate the influence of temperature on the early otolith growth and development in P. olivaceus by examining natural (15–19.5 °C) and constant (20 ± 0.5 °C) temperature regimes. The findings indicated that the initial daily ring appeared on the fifth day after hatching, with the regular formation of daily increments observed under both temperature regimes. Throughout the incubation period (0–30 days), no significant difference in growth rate was observed between the two temperature regimes. However, from days 35 to 50, the growth rate was significantly higher under the natural temperature regime than under the constant temperature regime. Morphological changes in otoliths differed between the two temperature regimes, with more distinct daily rings observed under the natural temperature regime than under the constant temperature regime. Furthermore, otolith growth strongly correlated with fish growth, with otolith size positively correlated with total length. This study demonstrated that the temperature regime significantly affected the early growth of otoliths and the formation of daily increments, offering essential data for reconstructing early life history and assessing stocking and release success. Full article

X-ray electron probe microanalyzer technology was used to study the microchemistry and habitat history of Coilia nasus collected from the Dawanzhou section of the Yangtze River between May and June 2023. The Sr/Ca ratio from the otolith core to the otolith diameter was low (640–1100 µm), representing the first stage of development. In the second stage, C. nasus exhibited two distinct types. The first type, which included individuals 5HK05 and 6HK03, exclusively inhabited brackish estuarine waters. The second type, comprising 13 individuals, resided in higher-salinity seawater environments (Sr/Ca > 7). Furthermore, individuals 5HK01, 5HK03, 5HK07, and 6HK05 displayed a phase with a high Sr/Ca ratio compared to other fish. Freshwater coefficient analysis indicated that C. nasus in the Dawanzhou water area was unlikely to continue upstream to Dongting Lake in the middle reaches of the Yangtze River but may have entered Poyang Lake through its mouth or reproduced in its upper reaches. Analysis of sexual maturity and migration history suggested that the Dawanzhou section primarily serves as a migration channel for C. nasus, with a potential spawning ground for this high-value fish located nearby. Full article