Freshwater ecosystems are among the most threatened environments worldwide, and nowhere is this more evident than in South America (Gomes Barbosa et al., 2024; Sayer et al., 2025; Vardakas et al., 2025). These rivers, lakes and floodplains harbour extraordinary fish diversity, sustain essential ecosystem services and face mounting pressures from dam construction, deforestation, overfishing, mining and climate change (Boschman et al., 2023; Fernandez et al., 2024; Malecha et al., 2025; Oliveira et al., 2020). In such fragile systems, conservation and management require the most current ecological knowledge, yet a hidden obstacle repeatedly undermines this process: the long lag between fieldwork, data acquisition and the eventual publication of scientific results (Christie et al., 2021; Dudgeon van Rees et al., 2025). Here, we present publication delays as a systemic barrier to conservation and argue that publication delays deserve far more attention than they currently receive (Christie et al., 2021; Hocherman et al., 2025). Although often considered a minor inconvenience of academic life, in the context of rapidly global change, the time lag to publication renders research outcomes unfit for purpose and reduces the chance of real-world impact (Christie et al., 2021; Sayer et al., 2025). If dissemination of results by the scientific community takes too long to communicate what it already knows, our capacity to guide urgent decisions is weakened, and the gap between knowledge and action only grows wider (Christie et al., 2021; van Rees et al., 2025). This ‘knowledge-action gap’ is not merely a bureaucratic issue, but a critical failure in the science-policy interface. The urgency is underscored by assessments showing that one-quarter of freshwater fauna is already threatened with extinction, a situation exacerbated by climate change and habitat fragmentation (Malecha et al., 2025; Sayer et al., 2025). Although scientists meticulously document declines and propose recovery plans, the slow pace of traditional publishing means that by the time findings reach managers and policymakers, the ecological reality on the ground may have already shifted, thus rendering conservation strategies obsolete before they are even implemented (van Rees et al., 2025). This lag effectively creates a perpetual state of reactive, rather than proactive, conservation. The extent of publication delays in freshwater fish ecology has rarely been quantified, yet their impact on the pace of scientific communication is considerable. In the process of collating a scientometric analysis of freshwater fish ecology in South America (Oliveira et al. in review), we were struck by how pervasive these delays are. Indeed, our overview revealed that publication lags are both widespread and substantial, with a mean delay of 4.6 years and a median of 3 years between field sampling and publication, with extreme cases stretching up to 26 years (Figure 1). Essentially covering multiple generations of fish. These findings align with earlier reports. De Santana et al. (2020) described publication delays of 4–10 years in age and growth studies of freshwater fish in South America, whereas Robalino-Mejía et al. (2025) documented an even longer mean lag of 8.4 years in Ecuadorian bony fishes. Similarly, Doria et al. (2021), in an article addressing the threat of non-native fishes in the Amazon, noted the existence of a ‘time lag’ between field data collection and the formal reporting of occurrences, although no numerical quantification of the delay was provided. Taken together, these studies reveal that delayed publication is not an anomaly but a systemic feature of freshwater fish research in South America and likely beyond (Dudgeon van Rees et al., 2025). Publication lags are not isolated cases linked to a few unlucky projects but rather a structural feature of how ecological research is conducted, processed and communicated in South America. Recognising the scale and proximal causes of the problem is a first step towards solutions. These persistent delays are not accidental but are symptoms of deeper structural constraints that shape South American ichthyology. Many research institutions operate under chronic unpredictable funding, leading to interrupted projects, high staff turnover and long intervals between data collection and publication (Lazcano, 2025; Ramalho et al., 2025). Linguistic and geographic barriers add to the challenge: writing and reviewing in English extend timelines, whereas high-impact journals often have protracted peer-review processes (Turba et al., 2025; Horbach Wróblewska, 2025). Together, these institutional, linguistic and financial obstacles slow down the pace of ecological communication, meaning that insights vital to conservation often reach decision-makers only after the ecosystems they describe have already changed. This systemic delay creates a dangerous paradox. Take a not-too-far-fetched hypothetical: by the time a study on the diet of a critically endangered fish is published, the population may have already collapsed – or the river system it inhabits may have been irreversibly altered by a newly built dam (Fernandez et al., 2024; Sayer et al., 2025). The consequences of such lags are significant and extend far beyond academia (Bayanbayeva, 2025; Trueblood et al., 2025). In tropical rivers and floodplains, fish populations are highly dynamic, shifting with seasonal cycles, flood pulses and short generation times (Chea et al., 2020; Cuesta et al., 2024; Oliveira et al., 2024; Qiu et al., 2025). Ecological knowledge that is 3, 5 or 10 years old may no longer reflect present-day conditions, and what was once accurate can quickly become obsolete (Christie et al., 2021; Hocherman et al., 2025). Our research, and that of others, confirms that the science meant to inform conservation is often describing an ecosystem that no longer exists (de Santana et al., 2020; Robalino-Mejía et al., 2025). This renders management actions based on such outdated information not just inefficient but potentially detrimental, misdirecting scarce resources and failing to address the most pressing contemporary threats (van Rees et al., 2025). The consequence is a vicious cycle where conservation practice, starved of timely data, struggles to demonstrate effectiveness, further eroding public and political support for evidence-based action. This matters deeply because conservation assessments and fisheries management depend on the timeliness of data (Dudgeon Robalino-Mejía et al., 2025). This temporal obsolescence of data creates a dangerous illusion of knowledge, where managers and policymakers believe they are acting on the best-available science, whereas in reality, they are navigating by an old and inaccurate map (Hocherman et al., 2025; Trueblood et al., 2025). For instance, a fishery quota set using a stock assessment from a decade prior could either sanction overharvesting of a population that has since declined or, conversely, unnecessarily restrict a community that depends on a resource that has proven more resilient (de Santana et al., 2020). Similarly, a conservation status on the IUCN Red List might remain unchanged for years, not because the species is stable but because the new data demonstrating its rapid decline are still trapped in the publication pipeline (IUCN, 2024; Robalino-Mejía et al., 2025). This systemic delay effectively forces us to fight the fires of today's biodiversity crisis with yesterday's intelligence, ensuring that our responses are perpetually inadequate and that the goal of ‘bending the curve’ of freshwater loss becomes increasingly elusive (Dudgeon van Rees et al., 2025). Recognising these challenges is essential, but recognition alone is insufficient (Piret et al., 2025). Practical actions are both possible and urgently needed (Satterwhite et al., 2020). Wider adoption of preprint platforms and data papers could accelerate the visibility of ecological findings, ensuring that knowledge enters the public domain quickly, even before peer review is complete (Chigarev, 2025; Nakysbekova et al., 2025; Prosée Ladouceur et al., 2022). International collaborations, already central to South American ichthyology, must go beyond data collection and move towards greater equity by supporting local researchers in analysis, writing and publication (Gomes Barbosa et al., 2024). Strengthening regional journals such as Neotropical Ichthyology would also help reduce delays, providing culturally relevant and accessible publication outlets with fewer barriers (Debat et al., 2025; Oliveira et al., 2025). These measures will not solve every aspect of the problem, but they represent realistic, achievable steps towards narrowing the gap between data collection and scientific communication (Christie et al., 2021). However, without these reforms, we risk managing South America's freshwater ecosystems based on a historical reality, not a current one, fundamentally undermining initiatives such as the emergency recovery plan for freshwater biodiversity (Twardek et al. 2021). The solutions, from preprints and data sharing to equitable partnerships and strong regional journals, are not merely technical fixes but a necessary call to action to address this escalating threat to scientific progress (Christie et al., 2021; Piret et al., 2025). Wider adoption of preprint servers, for instance, has been proven to stay ahead of the curve in biology, accelerating the dissemination of crucial findings (Prosée Ladouceur et al., 2022). Furthermore, international collaborations must evolve beyond data extraction towards greater equity, ensuring that local researchers lead in analysis and publication, thereby strengthening the entire research ecosystem (Heleta Oliveira et al., 2025). These are the realistic, achievable steps we must take. The choice is clear: we can continue to document the decline of these ecosystems with meticulous but delayed precision, or we can transform our practices to generate and disseminate the timely knowledge necessary to avert it. For the future of the continent's extraordinary aquatic life, the latter is the only acceptable path. The conservation stakes demand urgency (Cao et al., 2022; Mori et al., 2024; Piret et al., 2025). A 3-year median lag may seem modest on paper, but in rivers where fish communities can shift within a single season, such delays can render ecological knowledge obsolete (Cano et al., 2025; Löki et al., 2023; Pander et al., 2024). For some species, a single publication lag may mean the difference between proactive conservation and a missed opportunity to prevent decline (Christie et al., 2021; Johnson Trueblood et al., 2025). If freshwater fish ecology is to play its intended role in guiding conservation and policy in real time, then time itself must be treated as a critical dimension of ecological research (Dudgeon they are critical conservation interventions in their own right (Christie et al., 2021; Trueblood et al., 2025). By treating time with the same urgency as we treat funding and fieldwork, we can ensure that our science doesn't just arrive, it arrives in time to make a difference. Elioenai da Silva Oliveira, Felipe Polivanov Ottoni and Josie South: conception, editing and revisions. Elioenai da Silva Oliveira: original draft. This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil (finance code 001, grant no.: 88887.699722/2022-00 to Elioenai da Silva Oliveira), and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil (grant no.: 306490/2024-2 to Felipe Polivanov Ottoni and CNPq PPBio project no.: 441189/2023-7). Josie South acknowledges funding from the UK Research and Innovation (UKRI) Future Leaders Fellowship (grant no.: MR/X035662/1). Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
Oliveira et al. (Wed,) studied this question.