Fish Recruitment Research Articles

Anomalous sea temperatures can impair coral reef fish recruitment

Understanding how temperature affects coral reef fish recruitment success is crucial for assessing impacts of ocean warming on coral reef resilience. We utilized a long-term fish survey dataset along the west coast of Hawai‘i Island to investigate the role of sea surface temperature (SST) in influencing recruitment timing and density. The dataset consisted of 17 years of surveys, with 25 sites annually surveyed in the months of May, July, September and November. We found that peak recruitment, i.e. the maximum number of recruits recorded across all surveys per year, usually occurred during July surveys. For sites where peak recruitment for that year occurred outside July, there were significantly fewer fish recruits than for sites whose peak recruitment occurred in July. In addition, the timing of peak recruitment is influenced by anomalously warm or cool years prior to spawning. The decrease in recruit density outside these times is likely influenced by recruits being exposed to temperatures warmer and cooler than their optimum. Our results show that climate variability is having an impact on the timing of peak recruitment, creating a mismatch between the thermal optimum of developing recruits and the thermal environment they develop in, negatively affecting recruit density in critical coral reef habitats. Altered and reduced recruitment has the potential to disrupt reef community structure and long-term fisheries sustainability in Hawai‘i, with important management implications for coral reefs in the future.

Broad scale community-level larval fish survey of southern Lake Erie

Abstract The early-life history stages of fish are sensitive to environmental change and therefore can indicate habitat quality as well as help predict recruitment of resident and transient fishes. In 2019, as part of the Lake Erie Cooperative Science and Monitoring Initiative, we conducted a lake-wide assessment of the ichthyoplankton community in U.S. nearshore waters and international offshore waters. The goal of this work was to characterize the larval fish community across the lake and assess species composition, phenology, and distribution of larvae. Ichthyoplankton were sampled weekly using bongo nets at ports beginning at the Detroit River and along the southern shore of Lake Erie to Dunkirk, NY, and less frequently in the Niagara River and offshore areas. Larval fish were present from March 26 through August 29, 2019. The first taxon to emerge was Lake Whitefish in all basins, followed by Walleye, Yellow Perch, and catostomids, depending on port. Mean total density peaked in mid-June due to high catches of Gizzard Shad, Morone spp., and Freshwater Drum in the western basin. Few fish were collected in the offshore sites. Taxa richness, diversity, and larval density were higher in the western basin and lower in the central and eastern basins, generally following the productivity gradient. This was the first study to provide a comprehensive community assessment of the ichthyoplankton community of Lake Erie and can provide a baseline to assess future change, especially in community composition or phenology, of larvae which are likely to respond to climate and habitat change.

Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus.

Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Creating wetland islands to enhance shoreline habitat for fish recruitment in a modified shallow lake

Abstract Soft shoreline engineering is increasingly used to combine shoreline fortification with the enhancement of biodiversity and biological production of land–water transitions. From 2016 to 2021, the large‐scale ecosystem restoration project Marker Wadden has created new multiple wetland islands from local sediments in the highly modified Lake Markermeer, the Netherlands. Instead of replacing steep rip‐rap shorelines with soft shorelines, new islands with soft land–water transitions were engineered to offset the marked declines in bird and fish populations in this Natura 2000 area, protected under the European Union Birds and Habitats Directives. This new approach was evaluated by assessing the added value of the newly created wetland islands with soft shorelines to the existing steep rip‐rap fortified shores of the lake, for the enhancement of fish spawning and nursery habitat. Young‐of‐the‐year fish densities at the Marker Wadden islands were highest in sheltered bays and wetlands with nutrient‐rich silt sediments, and lowest at wind‐exposed sandy beaches. Both newly engineered soft shorelines and existing rip‐rap shorelines contributed to habitat diversity, although fish densities declined considerably with increasing exposure to wind‐induced wave power. Building soft shorelines as a new archipelago instead of replacing existing shoreline habitats increased the total length of the land–water transitions in the lake. The 800 ha Marker Wadden archipelago covers only 1% of the 70,000 ha lake surface area, but provides a 16% increase in shoreline habitat and a fivefold increase in soft shoreline for the lake. We conclude that designing wetland islands as a means of lake restoration can contribute effectively to sheltered habitat enhancement for fish spawning and nurseries, and thereby to the potential conservation of fish communities. The approach of building islands achieves this without compromising the complementary functionality of the original, more mature, shorelines of the lake.

Spatial Density, Biomass, and Composition of Crustacean Zooplankton on Lake Michigan Beaches

Ecosystem alterations to Lake Michigan (LM), such as the invasion of dreissenid mussels, have decreased the abundance of phytoplankton and, subsequently, zooplankton, which has implications for Great Lake fisheries. The community composition of zooplankton has also been altered over the past 20 years in LM, shifting the summer dominance from cladoceran to calanoid taxa. However, most of our information on zooplankton community dynamics is from deeper pelagic zones. The nearshore beach (≤1 m) habitat, which serves as a critical nursery for some larvae and juvenile fish, is composed of different zooplankton taxa than deeper zones, but limited data are available for comparison. We conducted a standardized summer sampling campaign to characterize the zooplankton community across 32 beaches in LM. We found the lowest crustacean zooplankton density and biomass on northern LM beaches and a higher zooplankton density and biomass on Greater Green Bay and central LM beaches, which had warmer water temperatures. Smaller-bodied cladocera (mainly Bosmina) and cyclopoid taxa were the most abundant groups on beaches. Our results provide the first comprehensive characterization of zooplankton on beaches in the Great Lakes, with applications for other lake systems. These results may help identify potential “hot spots” of fish recruitment for management.

Evaluating robustness of harvest control rules to climate-driven variability in Pacific sardine recruitment

Climate-driven changes in ocean temperatures, currents, or plankton dynamics may disrupt pelagic forage fish recruitment. Being responsive to such impacts enables fisheries management to ensure continued sustainable harvest of forage species. We conducted a management strategy evaluation to assess the robustness of current and alternative Pacific sardine harvest control rules under a variety of recruitment scenarios representing potential projections of future climate conditions in the California Current. The current environmentally informed control rule modifies the harvest rate for the northern sardine subpopulation based on average sea surface temperatures measured during California Cooperative Oceanic Fisheries Investigations field cruises. This rule prioritizes catch at intermediate biomass levels but may increase variability in catch and closure frequency compared to alternative control rules, especially if recruitment is unrelated to ocean temperatures. Fishing at maximum sustainable yield and using dynamically estimated reference points reduced the frequency of biomass falling below 150 000 mt by up to 17%, while using survey index-based biomass estimates resulted in a 14% higher risk of delayed fishery closure during stock declines than when using assessment-based estimates.

Major shift in the copepod functional community of the southern North Sea and potential environmental drivers

Abstract Copepods form the bulk of secondary production in marine ecosystems and are a major resource for higher trophic levels. Copepods are highly sensitive to environmental changes as they are ectotherms with a short life span whose metabolism and development depend on abiotic conditions. In turn, changes in their functional structure (i.e. functional trait composition) can have impacts on ecosystems. We examined changes in the copepod functional community in the North Sea over the past five decades, using a trait-based approach. We observed a shift around 1986–1988: the copepod community was initially dominated by larger herbivores, with a long development time, diapause ability, and highest abundances in summer. This community changed abruptly after 1986–1988, to a dominance of smaller carnivore taxa, with shorter development times, less ability to enter diapause, and that display higher abundances in autumn. This rapid reorganization could be driven by higher water temperatures, lower dinoflagellate abundances, and lower nutrient concentrations. These changes could impact adjacent trophic levels, such as phytoplankton on which several species graze or fish larvae, leading to a mismatch situation with consequences for fish recruitment. Our results emphasize the impact that global and regional changes could have on coastal ecosystems through the role played by copepods.

Can regime shifts in reproduction be explained by changing climate and food availability?

Marine populations often show considerable variation in their productivity, including regime shifts. Of special interest are prolonged shifts to low recruitment and low abundance which occur in many fish populations despite reductions in fishing pressure. One of the possible causes for the lack of recovery has been suggested to be the Allee effect (depensation). Nonetheless, both regime shifts and the Allee effect are empirically emerging patterns but provide no explanation about the underlying mechanisms. Environmental forcing, on the other hand, is known to induce population fluctuations and has also been suggested as one of the primary challenges for recovery. In the present study, we build upon recently developed Bayesian change-point models to explore the contribution of food and climate as external drivers in recruitment regime shifts, while accounting for density-dependent mechanisms (compensation and depensation). Food availability is approximated by the copepod community. Temperature is included as a climatic driver. Three demersal fish populations in the Irish Sea are studied: Atlantic cod (Gadus morhua), whiting (Merlangius merlangus) and common sole (Solea solea). We demonstrate that, while spawning stock biomass undoubtedly impacts recruitment, abiotic and biotic drivers can have substantial additional impacts, which can explain regime shifts in recruitment dynamics or low recruitment at low population abundances. Our results stress the importance of environmental forcing to capture variability in fish recruitment.

Acoustic enrichment trials using autonomous cameras on a Hawaiian coral reef

Playbacks of ambient sound from healthy shallow coral reefs, known as acoustic enrichment (AE), can attract fish larvae and potentially coral larvae to degraded or artificial reefs. Large-scale studies face power supply challenges and require less intensive in-person surveys of recruited larvae (≤500 μm) and fish. Here, we present a preliminary assessment of artificial structure deployments with AE, conducted between July and September 2023 in Kane’ohe Bay (Oahu, Hawai’i). The artificial structures were designed to attract herbivorous juvenile reef fish and subsequently suppress algal growth. The work is part of a future artificial reef construction project in Hawai’i where in-person surveys and frequent battery replacements are logistically challenging. The deployments consisted of one control and one treatment site 65 m apart, in 5 m water depth and 10 m from the natural reef. To document ecosystem responses, both sites use open-source burst-mode autonomous cameras, a directional vector sensor seafloor acoustic recorder, and hydrophones. A 3.8 kW-h NiMh battery supply powers sound output for three weeks during evening hours. We discuss preliminary evaluations of AE and the validity of using autonomous cameras in evaluating performance in terms of fish recruitment and algal growth. [Work sponsored by DARPA.]

Stochastic modelling and synthesis of dynamic fish recruitment productivity in the Celtic Seas ecoregion

Abstract The Celtic Seas ecoregion (CSE) is undergoing climatic and ecosystem changes, which can induce changes in fish productivity. Globally, the productivity of many stocks has shown evidence of change over decadal timescales. Varying factors might drive these dynamics in the CSE, but for many stocks, these mechanisms have not been fully understood to be included in management advice. We study dynamic productivity for 28 stocks in the Celtic Seas by tracking integrated stochastic signals in the relationship between stock size and recruitment using state-space modelling applying Peterman’s Productivity Method. Our research objectives were to (i) fit Ricker stock–recruitment models with time-varying parameters to all age- or length-based assessed stocks in the CSE, (ii) evaluate which parameters vary in time, (iii) examine temporal characteristics of historical recruitment productivity, and (iv) evaluate productivity correlation across stocks. For 22 out of 28 stocks, at least one of the three time-varying parameter models had a better fit than the time-invariant model. In the CSE, fish productivity has diverse temporal patterns, with some stocks displaying relevant long-term decreasing productivity trends. Getting insight into temporal changes in recruitment productivity is very valuable and has important implications for sustainable fisheries.

Endocrine disruptive toxicity of cypermethrin in Labeo catla: Involvement of genes and proteins related to the HPG axis

Cypermethrin (CYP) is a synthetic pyrethroid abundantly used in agriculture and aquaculture. It is an established potent endocrine disruptor to fish, yet the molecular mechanism behind its reproductive toxicity remains unclear. In this study, fish Labeo catla (Catla) was exposed to environmentally relevant concentration of CYP (0.7 μg/L) and 0.14 μg/L for 30 days. The changes in circulating sex steroids, genes, and hormones linked to the hypothalamic-pituitary-gonadal (HPG) axis, stress response and associated histological alterations were studied. Significant decline (P < 0.05) in serum 17 beta (β) estradiol (E2), 11 ketotestosterone (11-KT), and brain (FSH and GnRH) were observed in 0.7 μg/L dose of CYP. These effects may be due to the down-regulated expression of the upstream genes of the HPG axis i.e. Kiss 1 and Kiss 2, which further downregulates the expression of the GnRH gene. The decreased level of E2 and 11-KT also affects the vitellogenin (Vtg) gene expression, reducing the production of Vtg, a crucial protein for ovarian development. Principal component analysis (PCA) revealed the relationship between CYP and the biosynthesis of sex steroids. The toxic effect of CYP was also visible in antioxidant enzyme assay and related histological alterations. Overall, the study elucidated that long-term exposure to CYP, even at an environmentally relevant dose, may affect reproductive potential and fish recruitment. The study provides important insights into molecular mechanisms underlying CYP-induced endocrine disruption in fish, and it also raises questions about CYP's potential toxicity at environmentally relevant concentration in terms of understanding ecological risk.

Recruitment of Psostlarval Spiny Lobster, Stone Crabs, and Larval Fish to Back-Reef Nursery Habitats in the Florida Keys, USA

Back reef areas contain a mosaic of relatively shallow habitats that serve as a key nursery for reef species. Expansive back reef habitats in the lower Florida Keys, USA border the Atlantic Ocean and the Gulf of Mexico. A combination of floating, artificial settlement substrates and plankton nets moored in channels connecting coastal waters and back reef habitats quantified spiny lobster (Panulirus argus) and stone crab (Menippe sp.) settlement, and larval fish ingress, respectively, during 1999 and 2002–2003. The key finding was that channels connecting coastal waters with back reef areas serve as conduits for ingressing larval spiny lobster, stone crabs, and fishes. The results highlight the important role of Atlantic Ocean sources of spiny lobster pueruli and lutjanid fish larvae in this back reef system, and Gulf sources of stone crabs. Spiny lobster settlement generally peaked in August and September and occurred on the Atlantic Ocean side of this back reef system; settlement of stone crabs peaked at the same time as spiny lobster yet occurred predominantly on the Gulf side. Recruitment of larval fish was higher on the Atlantic than the Gulf side, with 37% of fish species collected nearly exclusively on the Atlantic side and about 25% collected nearly exclusively on the Gulf side. Channel habitats appear critical to supporting the nursery role of back reef habitats and should receive special consideration in future ecosystem studies, as well as during spatial planning and evaluations of essential fish habitat.

The Importance of Assessing Water Quality in Tributaries: A Case Study in an Urban Waterway Using Zebrafish (Danio rerio)

Tributaries are important for fish recruitment and diversity. Here, we examine the biological impact of inorganic and organic contaminants in Paint Branch stream (PBS), a tributary of the Anacostia river in Washington D.C. The Anacostia has suffered severe ecological damage because of decades of pollution and deposited wastewater runoff; however, PBS, which connects to the northern part of the river, is forested and less urbanized, suggesting higher water quality. However, the impact of PBS water on early fish development has not been studied. To address this question, we examined if chronic (28 day) exposure to water collected from PBS can support the proper early development of zebrafish (Danio rerio), a vertebrate model in toxicological studies. We assessed their overall growth and swimming behaviors and correlated these results with a water quality analysis. The water chemistry identified high levels of calcium, sodium, and nitrate in PBS water samples. A gas chromatography–mass spectroscopy analysis of extracted non-polar compounds in the water column revealed siloxanes (congeners D6–D10) were the only component identified with &gt;90% certainty. In our fish experiments, we observed age-dependent increases in growth and eye development, consistent with normal development. In contrast, general swimming behaviors showed an early increase in angular velocity at 7 days postfertilization (dpf; p = 0.001) and a decreased total distance traveled at 14 dpf (p = 0.015) for PBS-treated larvae. Using the open field test, we observed that the PBS-treated fish made fewer visits to the edge at 7 (p = 0.01), 14 (p &lt; 0.001), and 21 dpf (p = 0.038) and spent significantly more time at the edge at 21 dpf (p &lt; 0.001). Fewer visits to the center were also noted at 14 and 21 dpf, suggesting reduced overall movement at these two ages in response to chronic PBS water exposure. Interestingly, by 28 dpf, no differences were noted in any parameter measured. Overall, these results indicate zebrafish larvae grew well in PBS water; however, their reduced movement and anxiogenic behavior suggested subtle behavioral abnormalities. The identified chemicals likely originated from runoff or sewage and have potentially deleterious consequences for fish living in PBS or migrating to/from upstream spawning/nursery locations.

Annual recruitment is correlated with reproductive success in a smallmouth bass population

Annual recruitment in fish is undoubtedly impacted by a vast number of biotic and abiotic factors. That is especially the case for fish species such as the black bass (species in the genus Micropterus), where there is extended parental care. Although much focus has been given in the past on determining the roles that many of these factors (e.g., temperatures, wind, flow rates, and habitat change) play in determining recruitment among the back basses, little attention has been given to assessing what role reproductive success plays in that determination. To address this question, we conducted a long-term study on two adjacent smallmouth bass (SMB) Micropterus dolomieu Lacepède, 1802 populations in eastern ON to assess the relationship between annual fry cohort size (FCS) (i.e., population-wide reproductive success) and annual recruitment. To measure population-wide annual FCS, we used snorkel surveys to conduct a complete census of nesting SMB males during the spawn from 1990 to 2015. During those surveys, we quantified mating success, determined which nests were successful or not, and calculated the number of independent fry produced each year by summing those numbers across all successful nests. Summer snorkel surveys from 1991 to 2016 assessed annual recruitment through visual counts of age 1+ juveniles. Results demonstrated a highly significant, positive, linear relationship between annual FCS and annual recruitment.

A statistical framework for identifying the relative importance of ecosystem processes and demographic factors on fish recruitment, with application to Atlantic Herring (Clupea harengus) in the southern Gulf of St. Lawrence

Despite the importance of recruitment for population dynamics and assessing stock status, limited information exists on the relative influence of various ecosystem and demographic factors on the recruitment dynamics of marine fishes. We develop a statistical framework to identify the ecosystem and demographic factors influencing the recruitment and of marine fishes and facilitate improved predictions of recruitment. We demonstrate the approach by examining the relative influence of ecosystem and demographic factors on the recruitment of southern Gulf of St. Lawrence spring and fall spawning Atlantic Herring (Clupea harengus) stocks, highlighting the benefit of considering multiple factors to better understand recruitment trends. We found different combinations of biological and physical ecosystem factors along with demographic had a significant influence on the recruitment and recruitment rate of spring and fall spawning herring. The study emphasizes the value of considering ecosystem characteristics when examining recruitment, provides a framework for researchers to investigate and model recruitment of other fish populations, and supports the continued development and implementation of ecosystem based fisheries management approaches for species such as Atlantic Herring.

Lagoon morphology as an overarching driver for perch breeding success

Fish spawning and nursery habitats are critically important for the maintenance and conservation of viable fish stocks. Understanding habitat use of breeding fish is therefore important. This study examines the spatial distribution of Eurasian perch (Perca fluviatilis) egg strand occurrence and larval density in 18 brackish water post-glacial land-uplift lagoons in the northern Baltic Sea. The aim of the study was to quantify spawning habitat characteristics and evaluate how geomorphological, hydrological, and biological parameters affect perch breeding. Egg strand occurrence was assessed by snorkeling whereas fish larvae and zooplankton were sampled using horizontal surface hauls. Egg strand and larval density increased with higher habitat isolation, i.e., bay morphology had a decisive role in determining early recruitment success. Moreover, egg strand occurrence and larval density correlated positively with water temperature, charophyte cover and negatively with salinity. The zooplankton community structure differed among lagoon types but neither zooplankton density nor diversity showed a clear association with egg strand or fish larvae abundance. However, cladocerans and copepods were abundant in the most enclosed bays, and their density correlated positively with perch larval density. Our findings comply with earlier studies highlighting the importance of bay isolation for fish recruitment strength. We call for a foreseeing coastal management planning, that apart from considering current status and trends, also integrates decadal long projections of isostatic land-uplift processes in conservation decisions to secure the long-term persistence of the best spawning and nursery areas.

Short and long-term temperature variations drive recruitment variability in marine and estuarine juvenile fishes

Understanding the long-term effects of climatic factors on key species' recruitment is crucial to species management and conservation. Here, we analysed the recruitment variability of key species (Dicentrarchus labrax, Platichthys flesus, Solea solea, Pomatoschistus microps and Pomatoschistus minutus) in an estuary between 2003 and 2019, and related it with the prevailing local and large-scale environmental factors. Using a dynamic factor analysis (DFA), juvenile abundance data were grouped into three common trends linked to different habitat uses and life cycle characteristics, with significant effect of temperature-related variables on fish recruitment: Sea surface temperature and the Atlantic Multidecadal Oscillation. In 2010, a regime shift in the North Atlantic coincided with a shift in the common trends, particularly a decline in P. flesus and S. solea trend. This work highlights the thermophilic character of fish recruitment and the necessity to investigate key biological processes in the context of species-specific responses to climate change.

Depensation in fish recruitment driven by context-dependent interactions with another predator

Recruitment depensation describes elevated juvenile mortality with declining adult population size which can prevent or delay stock recovery. Understanding the factors influencing when a population undergoes depensation provides resource agencies with targets for management action. Using estimates of depensation from 28 walleye (Sander vitreus, Percidae) populations in Wisconsin identified by Sass et al., (2021), we tested for potential abiotic and biotic predictors of walleye recruitment depensation. The best fitting model contained covariates for climate, land cover, and fish community composition, all interacting with the relative abundance of largemouth bass (Micropterus salmoides, Centrarchidae). The consistent interaction effect of largemouth bass across the other covariates suggests a key role of this species in regulating walleye recruitment dynamics at low population size. The risk of depensation was negatively correlated with largemouth bass abundance in our dataset, pointing towards continued challenges for walleye populations given the increasingly favorable social and environmental conditions for largemouth bass. Using the model, vulnerability to depensation was predicted for an additional 115 walleye lakes with insufficient data to directly estimate the risk of depensation. Predictions suggested that 73 prediction lakes are vulnerable to depensatory recruitment should population sizes significantly decrease. This predictive framework could be used to prioritize lakes for different management actions based on depensation strength and average adult population size. Lakes with low walleye abundances, but low risk of depensation, may be more likely to respond positively to management efforts and are likely better candidates than those where depensation effects are likely strong when abundance is low.

Flow and thermal regimes altered by a dam caused failure of fish recruitment in the upper Mekong River

Abstract Riverine fishes have been increasingly threatened by the global proliferation of both small dams and large hydropower projects to meet the soaring water, energy and food demands from growing human populations and urbanisation. However, empirical evidence of the direct effects on a specific species before and after dam construction and operation is rare. Causes of population decline vary among species and, although little known, they are of great importance for successful environmental flow regulation. We monitored the hydroenvironment and population dynamics of a Schizothoracinae fish (Schizothorax lissolabiatus) for 9 years before and after dam (i.e., Dahuaqiao) construction in the upper Mekong River to understand fish response processes and the underlying mechanisms. Optimal hydroenvironmental conditions for key reproduction stages (e.g., pre‐spawning, hatching and post‐hatching) were reconstructed using daily increment analysis of larval otoliths and hydroenvironmental data. The flow regime was substantially disrupted by the dam, and water temperature was only slightly changed. The disappearance of young of the year from downstream after dam operation indicates that the changed hydroenvironment caused recruitment failure in S. lissolabiatus. By matching optimal hydroenvironmental conditions for S. lissolabiatus reproduction with the monitored hydroenvironmental data series before and after dam operation, we found that changes in thermal regime alone caused narrowing of the reproduction window by an average of 41%, whereas flow‐regime change alone narrowed it by 96% and it was narrowed by 98% for thermal and flow changes combined. This study shows that the altered flow regime, but not the thermal regime, was the primary driver of the recruitment failure of S. lissolabiatus. The findings highlight the importance of prioritising flow‐regime management to improve recruitment success for S. lissolabiatus and to favour the persistence of other imperilled Schizothoracinae fishes and native species in dammed rivers.

Sedimentary DNA can reveal the past population dynamics of a pelagic copepod

Abstract Copepods play a key trophic role as secondary producers, transferring primary production to higher trophic levels such as fish. Copepod production contributes significantly to successful fish recruitment. Despite their importance, knowledge of copepod dynamics over several decades remains limited due to the lack of long‐term data series with adequate sampling and analysis. However, an understanding of long‐term copepod dynamics is urgently required to strive toward better management for sustainable aquatic ecosystems and fish recruitment. Sedimentary DNA (sedDNA) has been developing as a useful tool for reconstructing past plankton dynamics. This study evaluates whether sedDNA targeting the pelagic copepod, Eodiaptomus japonicus, in Lake Biwa (Japan) can be an effective tool for elucidating its past population dynamics. We applied a quantitative polymerase chain reaction method targeting the mitochondrial cytochrome c oxidase subunit I gene on two sediment cores and compared the detected sedDNA concentrations with the unique long‐term dataset of demographic traits, biomass, specific growth rate, production, subitaneous eggs, and resting eggs of E. japonicus. The sedDNA concentration of E. japonicus recovered from sediment layers correlated significantly with in situ production, biomass, and production of immediately hatching eggs but not with resting eggs or specific growth rate. Our study provides evidence for the effective use of sedDNA as a tracking tool for assessing past copepod production dynamics.