Population Ecology Research Articles

Coexistence and competitive exclusion in a time-periodic Lotka-Volterra competition-diffusion system

The evolutionary impact of both temporal periodicity and spatial heterogeneity on population ecology is a challenging problem. Hutson et al. (2001) [12] and Bai et al. (2022) [2] studied the effects of diffusion rates on the dynamics of a time-periodic Lotka-Volterra competition-diffusion system with identical interspecific competition abilities. In this paper, we consider the case of different interspecific competition coefficients. The obtained results can be divided into two groups. The first part focuses on the interplay between the diffusion intensities and the interspecific competition coefficients on the dynamics in the weak competition case. We provide some sufficient conditions on coexistence and competitive exclusion. The second part considers the dynamics for fixed diffusion coefficients and varying competition coefficients. We not only provide a complete classification on the dynamics when one of the interspecific competition coefficients is small, but also show the multiple coexistence periodic patterns by applying the bifurcation method.

Promise and limitations of 18S genetic screening of extracted fecal DNA from wild capuchins

Genomic screening of fecal DNA provides insight into diet, parasite infection dynamics, and other aspects of the ecology and pathogens of wild populations. Here, we amplify and sequence the V4/V5 regions of the eukaryotic 18S ribosomal RNA gene from fecal DNA of wild capuchin monkeys (Cebus imitator). We collected 94 fecal samples from 26 individuals, each sampled 1-4 times across a 19-month period and examined the eukaryotic diversity in 63 of these samples which had sufficient numbers and quality of reads during downstream analyses. We found a total of 234 distinct amplicon sequence variants (ASVs) classified as Eukaryotes in our samples. Of these, 66 were assigned to the phylum Nematoda. 64 ASVs are from taxa that possibly parasitize monkeys or their food items: 33 were assigned to lungworms (Superfamily Metastrongyloidae; genus Angiostrongylus), two to the genus Strongyloides, and one to the genus Austrostrongylus. The remaining 28 ASVs were assigned to nematodes that likely parasitize plants and/or invertebrates that the monkeys consume. Taken together with past dietary and coprological study of the same primate population, our results suggest that invertebrate consumption and parasitic infection, especially by lungworms, is common and widespread among this population of wild monkeys. We also discuss limitations of our approach, including the amplification of off-target ASVs, and make suggestions for future research. Overall, 18S screening shows promise for identifying various components of the capuchin gastrointestinal eukaryotic ecosystem, including parasitic helminths, and its utility will increase with the improvement of genetic databases.

Age and growth of the mountain dragon, Diploderma micangshanense (Squamata: Lacertilia: Agamidae)

Abstract Knowledge of life history is important for understanding population ecology. The genus Diploderma is one of the most diverse genera in the family Agamidae, and no data on the life history traits of Diploderma species have been reported to date. Here, the age and growth of a population of D. micangshanense were revealed using skeletochronology for the first time. Females have greater snout-vent length (SVL) than males, but the mean SVL did not significantly differ between the sexes. Age ranged from one to four years in both sexes, and mean ages were 2.24 ± 0.10 years for males and 2.28 ± 0.12 years for females. No significant sexual differences were detected in either age structure or mean age. Age and body size were significantly positively correlated in both sexes. The growth coefficient k (males: 0.510; females: 0.441) and growth rate (males: 4.33 ± 0.38; females: 4.91 ± 0.39) were similar in both sexes. These results have implications for the population dynamics and management of this species.

Population genomics of Lacticaseibacillus paracasei: pan-genome, integrated prophage, antibiotic resistance, and carbohydrate utilization.

Lacticaseibacillus paracasei has beneficial effects on human health and holds promising potential as a probiotic for use in the development of functional foods, especially dairy products. This species can adapt to a variety of ecological niches and presents fundamental carbohydrate metabolism and tolerance to environmental stresses. However, the population structure, ecology, and antibiotic resistance of Lc. paracasei in diverse ecological niches are poorly understood. Reclassification of Lc. paracasei as a separate species of Lacticaseibacillus has stimulated renewed interest in its research, and a deeper interpretation of it will be important for screening strains beneficial to human health. Here, we collected 121 self-isolated and 268 publicly available Lc. paracasei genomes discussed how genomic approaches have advanced our understanding of its taxonomy, ecology, evolution, diversity, integrated prophage-related element distribution, antibiotic resistance, and carbohydrate utilization. Moreover, for the Lc. paracasei strains isolated in this study, we assessed the inducibility of integrated prophages in their genomes and determined the phenotypes that presented tolerance to multiple antibiotics to provide evidence for safety evaluations of Lc. paracasei during the fermentation processes.

Forward hysteresis and Hopf bifurcation in an Npzd model with application to harmful algal blooms.

Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) models, describing the interactions between phytoplankton, zooplankton systems, and their ecosystem, are used to predict their ecological and evolutionary population dynamics. These organisms form the base two trophic levels of aquatic ecosystems. Hence understanding their population dynamics and how disturbances can affect these systems is crucial. Here, starting from a base NPZ modeling framework, we incorporate the harmful effects of phytoplankton overpopulation on zooplankton-representing a crucial next step in harmful algal bloom (HAB) modeling-and split the nutrient compartment to formulate an NPZD model. We then mathematically analyze the NPZ system upon which this new model is based, including local and global stability of equilibria, Hopf bifurcation condition, and forward hysteresis, where the bi-stability occurs with multiple attractors. Finally, we extend the threshold analysis to the NPZD model, which displays both forward hysteresis with bi-stability and Hopf bifurcation under different parameter regimes. We also examine ecological implications after incorporating seasonality and ecological disturbances. Ultimately, we quantify ecosystem health in terms of the relative values of the robust persistence thresholds for phytoplankton and zooplankton and find (i) ecosystems sufficiently favoring phytoplankton, as quantified by the relative values of the plankton persistence numbers, are vulnerable to both HABs and (local) zooplankton extinction (ii) even healthy ecosystems are extremely sensitive to nutrient depletion over relatively short time scales.

Co-parasitism in the face of predation: Effects of natural enemies on a neotropical mockingbird.

Co-parasitism is ubiquitous and has important consequences for the ecology and evolution of wild host populations. Studies of parasite co-infections remain limited in scope, with few experimental tests of the fitness consequences of multiple parasites, especially in natural populations. We measured the separate and combined effects of Philornis seguyi nest flies and shiny cowbirds Molothrus bonariensis on the fitness of a shared host, the chalk-browed mockingbird (Mimus saturninus) in Argentina. Using a two-factor experimental approach, we manipulated the presence of nest flies and cowbirds in mockingbird nests and assessed their effects on mockingbird haemoglobin levels, begging and provisioning rates, body size, and fledging success. We also monitored rates of nest predation in relation to parasitism by flies and cowbirds. Nest flies reduced the haemoglobin concentration, body size, and fledging success of mockingbirds, likely because mockingbirds did not compensate for parasitism by begging more or feeding their nestlings more. Cowbirds also reduced the fledging success of mockingbirds, even though they had no detectable effect on haemoglobin or body size. Nests with cowbirds, which beg more than mockingbirds, attracted more nest predators. There was no significant interaction between the effects of flies and cowbirds on any component of mockingbird fitness. The combined effects of nest flies and cowbirds were strictly additive. In summary, we show that nest flies and cowbirds both reduce host fitness, but do not have interactive effects in co-parasitized nests. Our results further suggest that predators exacerbate the effects of nest flies and cowbirds on their hosts. Our study shows that the fitness consequences of co-parasitism are complex, especially in the context of community-level interactions.

Citizen Science in the Study of Marine Biodiversity: The case of Iconic and Cryptic Syngnathids

Citizen science invites the public to participate in both scientific thinking and data collection. Citizen science adds new collaborators whose contributions help to gather or analyse data on a large scale particularly relevant for emerging questions about the distribution and abundance of organisms across space and time. Syngnathids are cryptic fishes that inhabits temperate and tropical sheltered, coastal marine waters. Pipefishes and seahorses are threatened by habitat loss and degradation. Unfortunately, data on biological and ecological aspects and population trends are rarely available in most species. More than half of the thirteen-syngnathid species inhabiting Spanish coasts are considered Data Deficient for population evaluation. Citizen science is an opportunity to improve data availability for the study of syngnathid population tendencies and monitoring. This contribution describes and discusses the approach followed by Sea Watchers citizen science platform. We analysed and discussed the data provided by the observers, and the distribution data of species based on citizen science surveillance. Citizen science achieved the expansion of spatial and temporal dataset of syngnathid distribution. However, the obtained information is affected by observers’ behaviour and suggest that the observers performed focussed surveys to find individuals of these slow motion iconic fishes, introducing biases in the data.

Corrigendum to “Population energetics of bacterial-feeding nematodes: Stage-specific development and fecundity rates” [Soil Biology and Biochemistry 28 (3) 271–280, 1996

Nematodes play significant roles in carbon and nitrogen biogeochemical cycles in soils. The contributions of individual species to these processes depend, in part, on differences in their population ecology. Formatting errors were discovered that made portions of our previously published work on this subject nearly unintelligible. Herein, we correct those errors.

Evolving to stay the same: life history evolution and tradeoffs in response to high and low total food

Food drives ecology and evolution, but few studies have directly investigated the impacts of the total amount of food on life history evolution within‐species. Among the limited number of available case studies that do directly test total food effects on life history evolution we still lack consensus, partially owing to incompletely described life histories. We explored life history tradeoffs across the whole life cycle, and the consequences for trait and population dynamics, in a marine copepod evolved under high and low total food using an integral projection model (IPM). Populations were subjected to high‐ and low‐food regimes and a common garden experiment after 30 generations of evolution. We then sampled and measured individual vital rates (growth, reproduction, and survival) from hatching until death, which were used to parameterise IPMs. Food regime had a significant but slight effect on life histories, which appeared ‘slow' and ‘fast' in low‐food and high‐food lineages, respectively. Low‐food lineages grew bigger and produced larger offspring to genetically compensate for their environment, but this compensation came with costs; notably shorter lifespans and less chance of producing clutches of eggs. Despite these differences, population ecology and fitness were similar in high‐ and low‐food lineages as anticipated by per‐capita rather than total food effects. Consequently, though natural planktonic populations may genetically mitigate the effects of climate‐induced food scarcity, there are limits to this compensation and likely unforeseen impacts effects for wider food webs.

Reduced Order Modelling of Shigesada-Kawasaki-Teramoto Cross-Diffusion Systems

Shigesada-Kawasaki-Teramoto (SKT) is the most known equation in population ecology for nonlinear cross-diffusion systems. The full order model (FOM) of the SKT system is constructed using symmetric interior penalty discontinuous Galerkin method (SIPG) in space and the semi-implicit Euler method in time. The reduced order models (ROMs) are solved using proper orthogonal decomposition (POD) Galerkin projection. Discrete empirical interpolation method (DEIM) is used to solve the nonlinearities of the SKT system. Numerical simulations show the accuracy and efficiency of the POD and POD-DEIM reduced solutions for the SKT system.

Density-Dependent Selection

Density-dependent selection, which promotes contrasting patterns of trait means at different population densities, has a long history in population genetics and ecology. The unifying principle from theory is that density-dependent selection operates on phenotypic traits whose values counter the effects of whatever ecological agent is limiting population growth, be it resource competition, predators, or pathogens. However, the complexity inherent in density dependence means that the same selective process can generate multiple outcomes, depending upon the details of how population density affects vital rates and the age or size structure of a population. Failure to appreciate the potential for multiple outcomes confounded many early studies of the process. Nonetheless, careful empirical work in laboratory studies, long-term field studies, and studies of sexual selection demonstrates the wide reach of density-dependent selection. The inconsistent outcomes observed in these studies call for renewed research into how the details of density dependence channel adaptive responses.

Hybridization in Canids-A Case Study of Pampas Fox (Lycalopex gymnocercus) and Domestic Dog (Canis lupus familiaris) Hybrid.

Hybridization between species with different evolutionary trajectories can be a powerful threat to wildlife conservation. Anthropogenic activities, such as agriculture and livestock, have led to the degradation and loss of natural habitats for wildlife. Consequently, the incidence of interspecific hybridization between wild and domestic species has increased, although cases involving species of different genera are rare. In Vacaria, a Southern city in Brazil, a female canid with a strange phenotype, which had characteristics between the phenotype of the domestic dog (Canis familiaris) and that of the pampas fox (Lycalopex gymnocercus), was found. Our analysis suggests that the animal is a hybrid between a domestic dog and a pampas fox, but future studies are necessary to investigate additional cases of this hybridization in nature. This finding worries for the conservation of wild canids in South America, especially concerning Lycalopex species. Hybridization with the domestic dog may have harmful effects on pampas fox populations due to the potential for introgression and disease transmission by the domestic dog. Therefore, future studies to explore the consequences of hybridization on genetics, ecology, and behavior of wild populations will be essential to improve the conservation of this species.

Estimating parasite-condition relationships and potential health effects for fallow deer (Dama dama) and red deer (Cervus elaphus) in Denmark.

Parasites can exert a substantial influence on the ecology of wildlife populations by altering host condition. Our objectives were to estimate single and multiparasite-condition relationships for fallow deer (Dama dama) and red deer (Cervus elaphus) in Denmark and to assess potential health effects along the parasite burden gradient. Fallow deer hosted on average two endoparasite taxa per individual (min=0, max=5) while red deer carried on average five parasite taxa per individual (min=2, max=9). Body condition of both deer species was negatively related to presence of Trichuris ssp. eggs while body condition of red deer was positively related to antibodies of the protozoan Toxoplasma gondii. For the remaining parasite taxa (n=12), we either found weak or no apparent association between infection and deer body condition or low prevalence levels restricted formal testing. Importantly, we detected a strong negative relationship between body condition and the sum of endoparasite taxa carried by individual hosts, a pattern that was evident in both deer species. We did not detect systemic inflammatory reactions, yet serology revealed reduced total protein and iron concentrations with increased parasite load in both deer species, likely due to maldigestion of forage or malabsorption of nutrients. Despite moderate sample sizes, our study highlights the importance of considering multiparasitism when assessing body condition impacts in deer populations. Moreover, we show how serum chemistry assays are a valuable diagnostic tool to detect subtle and sub-clinical health impacts of parasitism, even at low-level infestation.

FROM POPULATIONAL OBSERVATIONS TO AN ASSESSMENT OF THEIR STATE: EXPERIENCE FROM A COMPREHENSIVE STUDY ON THE DEMOGRAPHIC PARAMETERS OF THE WESTERN SIBERIAN POPULATION OF THE EUROPEAN PIED FLYCATCHER, <i>FICEDULA HYPOLEUCA</i> (MUSCICAPIDAE, PASSERIFORMES)

Key demographic parameters were calculated using the European pied flycatcher (Ficedula hypoleuca) as a model species for the study of bird population ecology. In the Tomsk Region, southeastern part of western Siberia, birds nesting in nest boxes situated in natural forests for 22 years were continuously studied. Where possible, life tables, probability models (CJS), and population matrix models were employed in the calculation of demographics. A comprehensive study of population characteristics made it possible to compare them with the results of other research and to demonstrate the degree of divergence in the estimation of demographic parameters obtained using different methods. On average, nestlings successfully left their nests in 87.6% of breeding attempts. The percentage of immigrants, residents, and autochthons in the static age distribution of females amounted to 41.7, 25.3, and 33.0%, respectively, vs 30.8, 25.3, and 43.9% in males, The maximum age for female autochthons was 7 years, compared to 8 years for male autochthons. Male residents lived to be x + 5 years old, while female residents lived to be x + 7 years old. Autochthonous males and females showed about the same local survival rates. These were the highest in yearlings (0.54) and gradually decreased with the age of individuals. The local survival rate of males of unknown origins is comparable to that of autochthonous males. Females of unknown origins had the lowest local survival rates. Birds could start nesting as young as one year old and as old as six years. Ringing revealed that 68.9% of males started breeding in their first year of life, compared to 59.9% of females that started in their first year. Only 39.2% of females and 46.3% of males among the birds that survived and returned to our control sites started breeding as yearlings, vs 66.9% of two-year-old females and 71.1% of males. The proportion of the birds that returned to their birth place amounted to 11.1%. Females produced 9.1 fledglings on average per lifetime, vs 9.6 fledglings for males. The minimum life expectancy for fledglings was 1.2–1.49 and 1.2–1.62 years, vs the maximum life expectancy for individuals that survived for one year, which was 1.94 and 1.96 years for males and females, respectively. For males and females, the generation time was 3.13–3.32 and 3.18–3.39 years, respectively. The sensitivity and elasticity analysis of the population growth rate based on the constructed projection matrix revealed that it was the survival rate of juvenile and sexually mature individuals between one and two years of age that primarily drove the population growth rate. Using the demographic data obtained for the species’ population in natural habitats in the Southeast of western Siberia and the population matrix model constructed on its basis, we believe it is possible to compare the state of populations inhabiting ecosystems, both unspoiled and disturbed (transformed), in various areas across the distribution range of the European pied flycatcher.

Insularity determines nestling sex ratio variation in Egyptian vulture populations.

Variation in offspring sex ratio, particularly in birds, has been frequently studied over the last century, although seldom using long-term monitoring data. In raptors, the cost of raising males and females is not equal, and several variables have been found to have significant effects on sex ratio, including food availability, parental age, and hatching order. Sex ratio differences between island populations and their mainland counterparts have been poorly documented, despite broad scientific literature on the island syndrome reporting substantial differences in population demography and ecology. Here, we assessed individual and environmental factors potentially affecting the secondary sex ratio of the long-lived Egyptian vulture Neophron percnopterus. We used data collected from Spanish mainland and island populations over a ca. 30-year period (1995-2021) to assess the effects of insularity, parental age, breeding phenology, brood size, hatching order, type of breeding unit (pairs vs. trios), and spatial and temporal variability on offspring sex ratio. No sex bias was found at the population level, but two opposite trends were observed between mainland and island populations consistent with the island syndrome. Offspring sex ratio was nonsignificantly female-biased in mainland Spain (0.47, n = 1112) but significantly male-biased in the Canary Islands (0.55, n = 499), where a male-biased mortality among immatures could be compensating for offspring biases and maintaining a paired adult sex ratio. Temporal and spatial variation in food availability might also have some influence on sex ratio, although the difficulties in quantifying them preclude us from determining the magnitude of such influence. This study shows that insularity influences the offspring sex ratio of the Egyptian vulture through several processes that can affect island and mainland populations differentially. Our research contributes to improving our understanding of sex allocation theory by investigating whether sex ratio deviations from parity are possible as a response to changing environments comprised by multiple and complexly interrelated factors.

Qualitative Shotgun Proteomics Strategy for Protein Expression Profiling of Fish Otoliths

Despite decades of research on fish otoliths and their capacity to serve as biochronological recorders, much remains unknown about their protein composition, the mechanisms by which proteins are incorporated into the otolith matrix, or the potential for using otolith proteins to provide insight into aspects of fish life history. We examined the protein composition of Atlantic cod (Gadus morhua) otoliths using a state-of-the-art shotgun proteomics approach with liquid chromatography coupled to an electrospray ionization-orbitrap tandem mass spectrometer. In addition to previously known otolith matrix proteins, we discovered over 2000 proteins not previously identified in cod otoliths and more than 1500 proteins not previously identified in any fish otoliths. These included three novel proteins (Somatolactin, F-actin-capping protein subunit beta, Annexin) primarily involved in binding calcium ions and likely mediating crystal nucleation. However, most of the otolith proteins were not necessarily related to otolith formation but rather to other aspects of fish physiology. For example, we identified sex-related biomarkers for males (SPATA6 protein) and females (Vitellogenin-2-like protein). We highlight some noteworthy classes of proteins having diverse functions; however, the primary goal here is not to discuss each protein separately. The number and diverse roles of the proteins discovered in the otoliths suggest that proteomics could reveal critical life history information from archived otolith collections that could be invaluable for understanding aspects of fish biology and population ecology. This proof-of-concept methodology paper provides a novel methodology whereby otolith proteomics can be further explored.

Mechanism and implications of pro-nature physical activity in antagonizing psychological stress: the key role of microbial-gut-brain axis.

Appropriate physical activities and a biodiversity-rich environment are conducive to the relief of psychological stress, and pro-nature physical activities are a combination of the two, which has good application potential in antagonizing psychological stress, but the intervention mechanism is still unclear. The microbiota-gut-brain axis is cyclically associated with psychological stress, and psychological stress can affect the microbiota through the gut-brain pathway, and conversely, the microbiota can also affect the psychological stress-induced symptoms. It is suggested that the microbe-gut-brain axis may provide a new perspective and target for the treatment of psychological stress-related diseases. Pro-nature physical activity can improve the number of Firmicutes, short-chain fatty acids, Akkermansia bacteria, and the gut-brain barrier and further affect the HPA axis, BDNF, and serotonin pathways of gut-brain two-way communication, thereby maintaining the body's homeostasis and reducing antagonistic psychological stress. According to the comprehensive influence of physical activities on the microbiota-gut-brain axis, a "green + exercise prescription hypothesis" in line with the holistic medical concept is revealed, which is expected to be effective in the prevention, alleviation, and treatment of irritable bowel syndrome and neurodegenerative diseases. It provides new means for treating psychological stress-related diseases such as mental disorders and mood disorders. In addition, it enlightens the construction of green infrastructure that is conducive to the diversified contact of microorganisms in outdoor physical activities venues and induces healthy interaction between the human body and the microbial population in the natural ecology. However, the current research is still in its early stages, and the intervention effect and mechanism of pro-nature physical activities need further demonstration in the future.

Moderate mobility and high density in a small area: the population ecology of the marsh fritillary Euphydryas aurinia in Transylvania (Romania).

The Natura 2000 network is one of the most important tools for nature conservation in the EU. Therefore, knowledge of the ecology of the species listed on the Habitats Directive annexes is of particular relevance. One of these species is the butterfly Euphydryas aurinia. Much is already known about the ecology of this species at the European level, but information on Romania is scarce. Therefore, in a study area northwest of Cluj, the species was intensively studied in a mark-release-recapture study over its entire flight period. The investigated population harboured many individuals and had a high density. The dispersal behaviour of the individuals was somewhat more pronounced than in Mediterranean and partly also high alpine populations, but roughly comparable to other populations of the nominotypic subspecies. Overall, the ecological differences to Central and Western European populations were not very pronounced, and many of the conservation-relevant statements on this species in Central Europe should also be largely valid in Romania.

Interrelationships and properties of parasite aggregation measures: a user’s guide

Aggregation of macroparasites among hosts is nearly universal among parasite-host associations. Researchers testing hypotheses on origins of parasite aggregation and its importance to parasite and host population ecology have used different measures of aggregation that are not necessarily measuring the same thing, potentially clouding our understanding of underlying epidemiological processes. We highlight these differences in meanings by exploring properties and interrelationships of six common measures of parasite aggregation, and provide a “user’s guide” to inform researchers’ decisions regarding their application. We compared the mathematical expressions of the different measures of aggregation, and ran two series of simulations and analyses. The first simulations tested the effect of random removals of parasites on aggregation levels under different conditions, while the second explored interrelationships between the measures, as well as between other individual parasitological sample measures (i.e. mean abundance, prevalence) and aggregation. Results of simulations and analyses showed that the six measures of aggregation could be separated readily into three groups: the variance-to-mean ratio (VMR) together with mean crowding, patchiness with k of the negative binomial, and Poulin’s D with Hoover’s index. These three pairs of measures showed differing responses to random parasite removals and differing relations with mean abundance and/or prevalence, highlighting that metrics capture different variation in other sample measures and different attributes of aggregation. We used results of our simulations and analyses, and a literature review, to list the properties, advantages, and disadvantages of each aggregation metric. We provide a comprehensive exploration of what is assessed by each metric, as a guide to metric choice. We implore researchers to provide enough information such that aggregation measures from each group are reported or can be readily calculated. Such steps are needed to allow large-scale analyses of variation in degrees of aggregation within and among parasite-host associations, to uncover epidemiological processes shaping parasite distributions.

Deep residual convolutional neural network based on hybrid attention mechanism for ecological monitoring of marine fishery

Understanding the ecological environment, population abundance, and growth status of marine organisms in the marine fishery is important to promote its sustainability. However, existing manual detection methods can cause some damage to marine ecology and are difficult to meet the demand for fast and accurate detection. In addition, light, shadows, and disturbances in the marine ecosystem can affect the effectiveness of intelligent detection methods. To address these problems, a deep residual convolutional neural network (DRCNN) based on hybrid attention mechanism (HAM) is proposed to detect marine organisms. The hybrid attention mechanism obtains key information from both channel and space dimensions of the input image. And the residual module is added to the deep convolutional neural network to iteratively extract image features while avoiding error accumulation. It is demonstrated experimentally that the HAM-DRCNN model achieves 93.17% image localization accuracy with a processing speed of 20.95 frames/s. Compared with the YOLOv5 and Faster R-CNN, the mean average precision of species classification is 91.36%, which is an improvement of 0.93% and 9.39%, respectively. In addition, excellent results are achieved on two other benchmark datasets. The method can accurately locate and complete the classification of marine organisms in underwater images and has practical application value.