Fish Age Research Articles

Spawning aggregation of blacktail snapper (Lutjanus fulvus) in an okinawan coral reef: lunar-phase periodicity of aggregation formation, seasonal consistency in fish spatial distribution, and fish size and age frequency in the aggregation site

Spawning aggregation of blacktail snapper (Lutjanus fulvus) in an okinawan coral reef: lunar-phase periodicity of aggregation formation, seasonal consistency in fish spatial distribution, and fish size and age frequency in the aggregation site

Age-Dependent Enhancement in Fecundity and Ova Diameter of <i>Schizopyge niger</i> (Heckel, 1838) in Dal Lake, Kashmir

Understanding the reproduction and recruitment pattern is essential for successful conservation of a species. Accurate estimates of fecundity plays acrucial role in comprehending fish population dynamics. The snowtrout, Schizopyge niger, is a Cyprinid fish widely distributed throughout the lakes of Kashmir valley and is one of the most important commercial fish species. In this study, we examined the age-dependent reproductive perfor-mance of female S. niger, aiming to gain insights into its breeding characteristics for the development of an optimal brood-stock management plan. The study involved 78 female S. niger specimens collected from Dal Lake during the spawning season, representing age groups of 2+, 3+, 4+, 5+, and 6+ years. Fecundity and ova diameter showed an increasing trend from age 2+ (3,971 eggs; 1.45 mm) to age 6+ (10,501 eggs; 2.00 mm). Total fecundity exhibited positive correlations with age, total weight, ovary weight, and ova diameter. Additionally, there was a positive correlation between ova diameter and fish age, with the highest fecundity and largest ova diameter observed in the 6+ years age group. Among each age group, fecundity and ova diameter varied significantly (p <0.05). Based onthese findings, for optimal broodstock management of S. niger, it is recommended to use females of the6+ years age group after assessing the quality of eggs.

Arctic fishes reveal patterns in radiocarbon age across habitats and with recent climate change

AbstractClimate change alters the sources and age of carbon in Arctic food webs by fostering the release of older carbon from degrading permafrost. Radiocarbon (14C) traces carbon sources and age, but data before rapid warming are rare and limit assessments over time. We capitalized on 14C data collected ~ 40 years ago that used fish as natural samplers by resampling the same species today. Among resampled fish, those using freshwater food webs had the oldest 14C ages (> 1000 yr BP), while those using marine food webs had the youngest 14C ages (near modern). One migratory species encompassed the entire range of 14C ages because juveniles fed in freshwater streams and adults fed in offshore marine habitats. Over ~ 40 yr, average 14C ages of freshwater and marine feeding fish shifted closer to atmospheric values, suggesting a potential influence from “greening of the Arctic.”

Declines in Brook Trout Abundance Linked to Atmospheric Warming in Maryland, USA

Salmonid fishes provide an important indicator of climate change given their reliance on cold water. We evaluated temporal changes in the density of stream-dwelling brook trout (Salvelinus fontinalis) from surveys conducted over a 36-year period (1988–2023) by the Maryland Department of Natural Resources in Eastern North America. Nonparametric trend analyses revealed decreasing densities of adult fish (age 1+) in 19 sites (27%) and increases in 5 sites (7%). In contrast, juvenile fish (age 0) densities decreased in 4 sites (6%) and increased in 10 sites (14%). Declining adult brook trout trends were related to atmospheric warming rates during the study period, and this relationship was stronger than the effects of land use change or non-native brown trout. In contrast, juvenile fish trends generally increased with elevation but were not related to air temperature trends or land use change. Our analysis reveals significant changes in several brook trout populations over recent decades and implicates warming atmospheric conditions in population declines. Our findings also suggest the importance of temperature for adult survival rather than recruitment limitation in brook trout population dynamics.

The use of age and growth techniques to quantify the age structure of carryover hybrid catfish (female Channel Catfish × male Blue Catfish) in commercial ponds in West Alabama

AbstractObjectiveIn West Alabama, catfish Ictalurus spp. producers routinely face the challenge of fish that exceed market size (aka “Big Fish”) in their commercial ponds. These fish are skilled at evading seine nets during harvest and can increase in size significantly before subsequent harvests occur. This is problematic for catfish producers because processing plants prefer catfish within the 0.45–1.81‐kg range and farmers are paid a premium price for catfish of this size. Due to their larger size and growth potential, hybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus) can become a more significant issue than Channel Catfish if they evade harvest. The objective of this study was to describe and quantify the age structure and growth rate of hybrid catfish that evade capture and remain in commercial ponds following harvest and grow beyond acceptable market size as defined by catfish processing plants (i.e., Big Fish).MethodsHybrid catfish were collected from 12 recently harvested commercial ponds in West Alabama from December 2021 to August 2022 using an electroshocking boat. Total length (mm), body weight (kg), and sex of collected fish were recorded, and lapilli otoliths were removed to estimate fish age and determine total length and total body weight at estimated ages.ResultIn this study, 1005 hybrid catfish were collected with the successful age estimation for 1001 catfish, ranging from 1 to 11 years. Results of this study indicate that hybrid catfish exceeded the premium size threshold in 2.72 years ± 8 months. Additionally, from age 2 to age 3, the average hybrid catfish gained 2.90 kg, growing from 0.40 to 3.30 kg. Growth rate was significantly affected by sex; males overall were predicted to weigh more than females based on the weight‐at‐age model.ConclusionHybrid catfish should be completely harvested from commercial ponds following 1 year of harvest to receive the premium price per kilogram of live fish. If a complete harvest is unsuccessful, farmers can receive a discounted price per kilogram of leftover hybrid catfish based on current market trends.

Akdeniz ve Karadeniz balıklarının yaş, büyüme ve ölüm çalışmalarının sistematik bir derlemesi

Age, growth, and mortality studies (AGMS) conducted in the Mediterranean and the Black Sea were reviewed. The main objective of this study was to find out the gaps on unstudied and less studied species. Names of the all fish species were obtained from fishbase. While the “native” and “endemic” species were taken into consideration, species “introduced”, “questionable”, “misidentified” and “error in a name” were excluded from the data set. Fishbase, semanticscholar and googlescholar were used to obtain the species related studies in June 2023. Graphs and tables were created to represent the results. Totally, 185 of 604 species have AGMS. 22 countries have investigated fish age, growth, and mortalities, and the first three countries are Türkiye, Italy, and Greece, respectively. In the Mediterranean and Black Sea, 796 AGMS were found. The top three of these families with the most species are Sparidae (177), Mullidae (87), and Mugilidae (66). Among the studied species, 86.49% of the species (160) are commercially important for fisheries, and 13.51% of the species (25) are non-commercial. 31 of the 160 species encounter existence problems. All accessible studies were used including studies’ references and it was observed that the most of the species (419) in the Mediterranean and Black Sea have no age or growth studies. This study clearly shows the gaps in AGMS in the Mediterranean and Black Sea regions.

Age and environment are the main drivers shaping the wild common sole (Solea solea) microbiota

Microbiota plays an essential role in fish growth and health and may be influenced by the changing environmental conditions. Here, we explored the microbiota of wild common sole, one of the most important fishery resources in the Mediterranean Sea, collected from different areas in the North Adriatic Sea. Our results show that the sole microbiota differs from that of the surrounding environment and among the different body sites (gill, skin and gut). Gut microbiota composition showed to be strongly related to fish age, rather than maturity, sex or sampling site. Age-related shifts in gut microbial communities were identified, with increased abundances of Bacteroidia and Desulfobacteria, unveiling potential microbial proxies for age estimation crucial for fisheries management. Our results expand the limited knowledge of the wild common sole microbiota, also in the light of the potential usefulness of the fish microbiota as a tool for future stock identification and connectivity studies.

Struggling with fish age, a comparison of otolith preparation techniques to unravel age and growth of boarfish, Capros aper (Linnaeus, 1758)

Fish age and growth data are crucial for understanding vital species’ traits and their populations. Boarfish is a pelagic species widely distributed in the Northeast Atlantic that is one of the most discarded non-commercial species on the Portuguese coast. Due to its potential valorisation as a new fishery in the Northeast Atlantic, boarfish has become object of interest in several published studies. However, since no age standard protocol has been implemented for boarfish, studies have used a variety of different otolith preparation techniques to estimate age, leading to contradicting and discrepant results. This research aims to consolidate biological insights into boarfish age and growth, lay the foundation for a standardized ageing protocol and serve as a benchmark study for the Portuguese west coast before commercial exploitation. Through the comparison of two otolith ageing methodologies, this study recommends using whole otoliths as the best method, revealing a maximum age of 15 years. The growth pattern estimated, indicated a biphasic growth pattern, with a faster initial growth rate that slows down at 2.4 years, the moment of change, when energy is allocated for sexual maturation. This finding was corroborated by a maturity ogive and analysis of fish size and otolith length relationship.

Evolution of cardiac tissue and flow mechanics in developing Japanese Medaka.

The effects of pressure drop across cardiac valve cushion regions and endocardial wall strain in the early developmental stages of a teleost species heart are poorly understood. In the presented work, we utilize microscale particle image velocimetry (μPIV) flow measurements of developing medaka hearts from 3 to 14 dpf (n = 5 at each dpf) to quantify the pressure field and endocardial wall strain. Peak pressure drop at the atrioventricular canal (ΔPAVC) and outflow tract (ΔPOFT) show a steady increase with fish age progression. Pressure drops when non-dimensionalized with blood viscosity and heart rate at each dpf are comparable with measurements in zebrafish hearts. Retrograde flows captured at these regions display a negative pressure drop. A novel metric, Endocardial Work (EW), is introduced by analyzing the ΔPAVC-strain curves, which is a non-invasive measure of work required for ventricle filling. EW is a metric that can differentiate between the linear heart stage (< 100 Pa-%), cardiac looped chamber stage (< 300 Pa-%), and the fully formed chamber stage (> 300 Pa-%).

From Data to Insight: Machine Learning Approaches for Fish Age Prediction in European Hake

From Data to Insight: Machine Learning Approaches for Fish Age Prediction in European Hake

The impact of shade net use on total nitrogen removal by duckweed (Lemna perpusilla) at different levels of catfish farming effluent

Duckweed (Lemna perpusilla) has been shown to reduce nutrient levels in aquaculture effluent, particularly total nitrogen, which can be caused by a variety of organic contaminants in water. Duckweed biomass is an important source of bioenergy and phytoremediation in aquaculture. This aspect makes it a viable solution for sustainable integrated aquaculture, although appropriate duckweed biomass development is critical to its success and long-term survival. Duckweed growth, as an autotroph, is controlled by two factors: nutrition and sunlight. The aquaculture production cycle changes nutrient content in medium culture based on feed, fish age, and density, while weather influences solar radiation. The study aims to investigate duckweed growth response and phytoremediation capacity by analyzing changes in catfish farming waste-water quality grouped by fish age (L1: 2 months, L2: 3 months, and L3: 4 months) and shade net treatment at 25 % sunlight blocking (N25), 50 % (N50), and no shade net (N0). The experiment was carried out in triplicate in a semi-outdoor growth system placed in a greenhouse. It comprised of three series of duckweed culture containers filled with catfish farming wastewater, each with a working volume of 50 L. A total of 48 duckweed culture containers were floated inside a series of Recirculating Aquaculture System (RAS) tanks. Biomass harvesting and water quality monitoring were done every three days for a period of 18 days. N25 had the highest biomass weight, productivity, and average TN elimination efficiency, with values of 225.21 ± 140.04 g, 50.05 ± 10.06 g/(m2.d), and 61.94 ± 8.01 %, respectively (P < 0.05). The N0 values were 190.80 ± 117.52 g, 42.40 ± 9.29 g/(m2.d), and 55.61 ± 6.85 % (P < 0.05). The lowest values observed in N50 were 72.27 ± 55.70 g, 16.06 ± 4.90 g/(m2.d), and 51.67 ± 4.10 % (P < 0.05). This study proved the optimal duckweed growth and TN removal effectiveness with N25 under varying light intensity, allowing for the long-term use of duckweed in waste management and integrated aquaculture.

Effects of buccal cavity parasite Ceratothoa carinata (Isopoda, Cymothoidae) on the condition and reproduction of its host fish Japanese scad Decapterus maruadsi.

All species of the isopod family Cymothoidae are obligate fish parasites, extracting nourishment through hematophagy and tissue consumption. To elucidate the detrimental effects of this parasitic relationship upon the host fish, we examined body length, weight of body, gonad, liver and stomach contents, and condition factor of Japanese scad Decapterus maruadsi infected with the buccal cavity parasite Ceratothoa carinata in different seasons. During the host fish's breeding season in July, the wet weight and condition factor of male and female host fish ages 1 and 2 were conspicuously diminished. No impacts were detected in September, after the breeding season. We found no impact of the parasite on the stomach content weight or signs of prey fish in the stomachs. Thus, parasite infection with C. carinata potentially diminishes the reproductive success of the host fish by negatively impacting the host's physiological condition, particularly during the breeding season.

Микроэлементный состав крови русского осетра

Establishing quantitative levels of chemical elements in the blood plays a leading role in studying the mi-croelement status of the body. The purpose of the work was to study the microelement composition of the blood and spleen of the Russian sturgeon Acipenser gueldenstaedtii (Brandt, 1833). The objects of the study were females and males of Russian sturgeon of different ages. The determination of metals was carried out using atomic absorption spectrometry. In each sample, iron, copper, manganese, zinc, nickel, cobalt, chromium, lead, and cadmium were determined. Specific features of the accumulation of chemical elements in the blood and spleen of Russian sturgeon have been revealed. The content of iron and zinc in the blood and spleen of fish is in the greatest quantities. At the same time, the concentration of zinc in the blood of fish, as well as the concentration of iron, depends on the systematic position of the fish, and falls within the limits of the concentrations of chemical elements according to A. P. Vinogradov: the content of iron and zinc in the blood of Teleostei is generally higher than in the blood of Elasmobranchii. Russian sturgeon belongs to the subclass Chondrostei and has characteristics of cartilaginous and bony fish, perhaps this can explain the amount of iron and zinc found in the blood. A positive correlation was revealed between iron and copper in the blood of female and male Russian sturgeon. At the same time, no gender differences were found in the content of chemical elements in the blood of female and male Russian sturgeon, with the exception of nickel, the concentration of which is higher in the blood of males. It has been shown that as fish age, the concentration of nickel, manganese, lead and copper in the blood increases.

Mitochondrial functions and fatty acid profiles in fish heart: an insight into physiological limitations linked to thermal tolerance and age.

Heart failure is among the first major consequences of heat stress in aquatic ectotherms. Mitochondria produce most of the ATP used by the heart and represent almost half of the volume in cardiac cells. It has therefore been hypothesized that mitochondrial dysfunction may be a major cause of heart failure associated with heat stress. The present study aims to investigate if CTmax is linked to the thermal sensitivity of cardiac mitochondria in the three-spined stickleback (Gasterosteus aculeatus), and if it is influenced by heart fatty acid composition and age. To do so, we measured the CTmax of 30 fish. The cardiac mitochondrial oxygen consumption was measured by high resolution respirometry at three temperatures and heart lipid profiles were obtained by gas chromatography (GC) coupled with a flame ionization detector (FID). Fish age was estimated via otolith readings. Fatty acid profiles showed no correlation with CTmax, but EPA levels were higher in older individuals. Mitochondrial respiration was measured in 35 fish using high-resolution respirometry. It was strongly affected by temperature and showed a drastic drop in OXPHOS respiration fed by complex I and complex I+complex II, while uncoupled respiration plateaued at CTmax temperature. Our results suggest that complex I is an important modulator of the impact of temperature on mitochondrial respiration at high temperatures but is not the main limiting factor in physiological conditions (maximal OXPHOS). Mitochondrial respiration was also affected by fish age, showing a general decrease in older individuals.

Factors Influencing Endangered Marine Species in the Mediterranean Sea: An Analysis Based on IUCN Red List Criteria Using Statistical and Soft Computing Methodologies

The Mediterranean Sea is the second largest biodiversity hotspot on earth, with over 700 identified fish species is facing numerous threats. Of more than 6000 taxa assessed for the IUCN Red List, a minimum of 20% are threatened with extinction. A total of eight key factors that affect vulnerability of marine fish species in the Mediterranean Sea were identified using the scientific literature and expert-reviewed validated databases. A database of 157 teleost fish species with threat status ranging from least concern to critically endangered was compiled. Nominal logistic curves identified the factor thresholds on species vulnerability, namely, age at maturity, longevity, and asymptotic length at 8.45 years, 36 years, and 221 cm, respectively. A second-degree stepwise regression model identified four significant factors affecting the threat category of Mediterranean fish species, namely, overfishing, by-catch, pollution, and age at maturity according to their significance. Predictive analysis using supervised machine learning algorithms was further employed to predict the vulnerability of Mediterranean marine fish species, resulting in the development of a framework with classification accuracy of 87.3% and 86.6% for Support Vector Machine (SVM) and Gradient Boosting machine learning algorithms, respectively, with the ability to assess the degree of variability using limited information.

Community Structure Characteristics and Changes in Fish Species at Poyang Lake after the Yangtze River Fishing Ban

To understand the fish community structure characteristics and changes in Poyang Lake after the Yangtze River fishing ban in 2021, seven sampling stations were established, namely in Hukou, Lushan, Duchang, Yongxiu, Nanjishan, Ruihong, and Poyang, for fishery resource surveys between 2020 and 2021. The results showed that 93 fish species were identified, belonging to 11 orders, 20 families, and 61 genera, which was an increase of 4.5% from before the fishing ban. Of these, 52 Cyprinidae species were identified, comprising the highest proportion (55.91%). Four invasive alien species (hybrid sturgeon, Cirrhina mrigala, Piaractus brachypomus, and Mugil cephalus) were identified, and the number of alien species in Poyang Lake was higher than before the fishing ban. Carnivorous and mid-lower-level fish showed a significant increase, accounting for 47.31% and 38.71% of the total species, respectively. Compared with the Yangtze River before the fishing ban, the body length and body weight of the main economic fish in Poyang Lake increased by 6.10–61.26% and by 15.14–291.57%, respectively. In terms of age structure, the proportion of major economically important fish aged 1 or 2 years decreased significantly, while the proportion of older fish increased substantially. There was little difference in the diversity of fish communities at different stations in Poyang Lake. In terms of biodiversity, the Shannon–Wiener index ranged from 2.158 to 2.909, with Poyang having the highest value and Nanjishan the lowest. Margalef’s index ranged from 4.265 to 6.459, with Lushan having the highest value and Nanjishan the lowest. Pielou’s index ranged from 0.617 to 0.822, with Duchang having the highest value and Nanjishan the lowest. Hence, the Yangtze river fishing ban has played an important and positive role in the restoration of fishery resources in Poyang Lake. However, long-term tracking and monitoring are needed to provide information to comprehensively evaluate the ecological impact of the Poyang Lake fishing ban.

A problem for the ages: Achieving reliable fish age information through quality management

Age information is central to assessment and management of fish populations. Age information must be reliable to have value, which depends on its quality. Quality assurance (QA) and quality control (QC) are processes often applied to some aspects of producing age information (e.g., annulus validation). However, we advocate for a more holistic approach which leverages QA/QC measures across all phases of the age information-generating process. Systematic implementation of QA/QC measures in a repetitive process is common in the manufacturing industry where it is known as a quality management system (QMS) but this framework is not well described in the fisheries literature. We designed and implemented a QMS that incorporates QA/QC measures across all phases of fish age information development: Collection, Interpretation, and Distribution. These measures are guided by six principles: Train, Simplify, Validate, Compare, Record, and Improve. In our QMS, the Train, Simplify, and Validate principles are largely guidance for QA measures, while Compare, Record, and Improve guide QC measures. We provide examples of common errors (or sources of error) in each phase, and how the guiding principles in our QMS address these errors. This is a QMS crafted as a holistic approach to managing the quality of fish age information; however, it has broad application as a conceptual framework for other repetitive processes in fisheries.

Exploring Growth Patterns of Maurolicus muelleri across Three Northeast Atlantic Regions

Maurolicus muelleri is an important component of mesopelagic ecosystems; nevertheless, we possess only limited knowledge about its biological features. We collected samples of M. muelleri from six scientific surveys between 2019 and 2021 in three geographical areas in the Northeast Atlantic waters (from South to North): the Bay of Biscay, the Celtic Sea, and the Norwegian Sea. Geographical variations in otolith growth, fish age, length, weight, and condition, as well as length–weight relationships and von Bertalanffy growth models (VBGMs), were investigated. Length-weight relationships revealed differences associated with the fish’s origin, paralleling the annual and daily otolith growth. VBGM parameters increased progressively northwards, in accordance with Bergmann’s rules. Fish length was positively related to the otolith radio, and Lee’s phenomenon was undetected. The impact of environmental variables, such as temperature and food availability, is debated, with these considered potential drivers of this variability. Populations may belong to separated units, either genetically or morphologically, representing differences in biological parameters as a signal of geographical divergence.

Determinants of per- and polyfluoroalkyl substances (PFAS) exposure among Wisconsin residents

BackgroundPer- and polyfluoroalkyl substances (PFAS) include thousands of manufactured compounds with growing public health concerns due to their potential for widespread human exposure and adverse health outcomes. While PFAS contamination remains a significant concern, especially from ingestion of contaminated food and water, determinants of the variability in PFAS exposure among regional and statewide populations in the United States remains unclear. ObjectivesThe objective of this study was to leverage The Survey of the Health of Wisconsin (SHOW), the only statewide representative cohort in the US, to assess and characterize the variability of PFAS exposure in a general population. MethodsThis study sample included a sub-sample of 605 adult participants from the 2014–2016 tri-annual statewide representative sample. Geometric means for PFOS, PFOA, PFNA, PFHxS, PFPeS, PFHpA, and a summed measure of 38 analyzed serum PFAS were presented by demographic, diet, behavioral, and residential characteristics. Multivariate linear regression was used to determine significant predictors of serum PFAS after adjustment. ResultsOverall, higher serum concentrations of long-chain PFAS were observed compared with short-chain PFAS. Older adults, males, and non-Hispanic White individuals had higher serum PFAS compared to younger adults, females, and non-White individuals. Eating caught fish in the past year was associated with elevated levels of several PFAS. DiscussionThis is among the first studies to characterize serum PFAS among a representative statewide sample in Wisconsin. Both short- and long-chain serum PFAS were detectable for six prominent PFAS. Age and consumption of great lakes fish were the most significant predictors of serum PFAS. State-level PFAS biomonitoring is important for identifying high risk populations and informing state public health standards and interventions, especially among those not living near known contamination sites.

Genomic prediction model optimization for growth traits of olive flounder (Paralichthys olivaceus)

Genomic prediction (GP) has emerged an effective tool for addressing the many shortcomings of traditional selective breeding, thereby enhancing the selection process. In this study, we optimized GP methods using 5-fold cross-validation to estimate genome-estimated breeding values for the weight traits of olive flounder (Paralichthys olivaceus). To accomplish our goal, we determined the parentage of the target broodstock and the ability of 11 prediction models to predict the weight traits of 1.8-year-old olive flounders, which were genotyped using a 70 K single nucleotide polymorphism (SNP) array. Moreover, our optimization efforts toward the predictive ability of genomic best linear unbiased prediction (GBLUP), Bayesian B (BB), and random forest (RF) methods encompassed changes in various aspects such as fixed effects, SNP quantity, population size, and phenotypic data collected at different fish ages. Additionally, we assessed the predictive ability for the total length and body depth of fish using GBLUP, BB, and RF. Among the 11 prediction methods used in this study, the BB (0.675), Elastic Net (0.679), and RF (0.698) methods exhibited the highest predictive abilities, whereas the GBLUP (0.637) method demonstrated the lowest. Incorporating information regarding fish sex as a fixed effect substantially improved the predictive ability of GBLUP and BB. For mean models, utilizing 3000–5000 random SNP markers resulted in a higher predictive ability, similar to that obtained using 50,000 SNPs. Increasing the population size reduced the standard deviation of the predictive ability. Notably, phenotypic records from 1.8-year-old fish exhibited a significantly higher predictive ability than those from the other age groups. Furthermore, GBLUP, BB, and RF provided higher predictive abilities for length (0.655–0.852) and body depth (0.665–0.861). These findings may significantly shape future olive flounder genomic selection programs and offer valuable insights into GP in aquaculture.