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Climate Change and Overfishing Threaten Caribbean Queen Conch Populations

The threatened queen conch ( *Aliger gigas* ) is a vital Caribbean species and significant economic resource facing population decline due to overfishing and limited resilience.

September 8, 20266 min readFrontiers in Marine Science | New and Recent Articles

Climate Change and Overfishing Threaten Caribbean Queen Conch Populations

Our take

The recent study estimating adult-stage abiotic suitability and potential distributional shifts for the threatened queen conch ( *Aliger gigas*) in the Caribbean Sea underscores a critical vulnerability within a vital ecosystem and a key economic driver for numerous coastal communities. The queen conch’s decline, driven by decades of overfishing compounded by limited larval dispersal and poor population connectivity, is well-documented. However, this research moves beyond the immediate pressures of exploitation to explicitly model the impacts of climate change, a factor increasingly recognized as a pervasive threat to marine biodiversity. Understanding these shifts is crucial, particularly given the broader context of ocean warming's impact on marine invertebrates, as illustrated by recent findings detailing how elevated temperatures alter swimming behavior in Caribbean king crab larvae Elevated temperature alters swimming behavior in Caribbean king crab larvae. The integration of adult occurrence records with benthic and surface-level ocean data—temperature, salinity, and pH—represents a significant advancement in predictive ecological modeling for this species. This approach, while complex, offers a data-driven framework for anticipating future habitat availability and informing proactive conservation strategies. The research also builds on broader efforts to map and understand marine ecosystems, echoing the detailed scientific insights into the marine diversity of the Crozet Basin and Crozet Plateau From Terra Incognita to ocean sanctuary: a review of scientific insights into the marine diversity of the Crozet Basin and Crozet Plateau.

The divergence in model estimations under moderate and extreme climate scenarios highlights a significant challenge in climate change projections: the inherent uncertainty in future climate pathways. While the optimistic scenario suggests relative stability in suitable habitat, the more severe projections indicate substantial losses, potentially leading to abrupt declines in queen conch populations. This variability underscores the need for robust, longitudinal data collection and adaptive management strategies. The study’s analysis, incorporating seagrass habitat and Marine Protected Area (MPA) distributions, further emphasizes the importance of considering these factors in conservation planning. Effective MPAs, coupled with sustainable fisheries management practices, can serve as refugia for queen conch populations, buffering them against the impacts of both overfishing and climate change. It’s also relevant to consider the logistical challenges of maintaining connectivity across vast ocean spaces, especially given the growing need for improved communication and data sharing amongst naval forces and researchers, a need underscored by the Indian Navy's pursuit of indigenous SATCOM terminals Indian Navy Seeks Indigenous SATCOM Terminals To Improve Connectivity Between Warships. The integrated data ecosystem required to effectively monitor and manage these populations demands collaborative efforts and technological innovation.

The reliance on abiotic suitability models, while scientifically rigorous, necessitates acknowledging the limitations inherent in such approaches. These models primarily focus on environmental conditions, potentially overlooking the complex interplay of biotic factors such as predator-prey relationships, disease dynamics, and competition with other species. A truly comprehensive understanding of queen conch population resilience requires an integrated approach that considers both abiotic and biotic drivers. Furthermore, the study’s focus on adult-stage suitability implies that larval dispersal patterns, already recognized as a limiting factor, may be further constrained by shifting ocean conditions. The potential for reduced connectivity between populations, coupled with declining habitat availability, raises concerns about the long-term viability of the species across its range. The use of validated, measurable data—a hallmark of rigorous scientific inquiry—is essential for refining these models and ensuring their utility in guiding conservation actions.

Ultimately, this research serves as a stark reminder of the interconnectedness of human activities, climate change, and marine ecosystems. Anticipating future habitat availability for the queen conch—and other commercially and ecologically vital species—is paramount for informing sustainable management practices. The divergence in model projections under different climate scenarios compels us to ask: how can we best balance the need for immediate action with the inherent uncertainties of long-term climate predictions, and what innovative data integration strategies can enhance our ability to build ocean intelligence and safeguard these crucial resources for future generations?

The queen conch (Aliger gigas) is a key native species of the Caribbean Sea and a primary source of income for thousands of fishers. Historically, it has been a highly valuable resource for the fishing sectors of countries such as the Bahamas, Turks and Caicos, Honduras, and Nicaragua. However, the species has been extensively overfished across the region due to its high economic value and inherent susceptibility to harvest. Overfishing, combined with limited larval dispersal, low recruitment, and poor population connectivity, has led to a drastic decline in population numbers of the species, resulting in its current classification as Threatened. Despite this status, likely impacts of climate change on its populations remain poorly understood, posing significant challenges to conservation efforts. To address this gap, we integrated adult occurrence records with both benthic- and surface-level, data on ocean temperature, salinity and pH to develop ecological niche models evaluating adult-stage abiotic suitability in the Western Atlantic and potential distributional changes under three climate change scenarios of Shared Socioeconomic Pathways (optimistic, moderate, and extreme). Suitability estimates were later analyzed in light of seagrass habitats and the distribution of Marine Protected Areas (MPAs) in the region. Our analyses suggested a high spatial stability in abiotically suitable areas at the benthic level across all time horizons under the optimistic climate change scenario. Conversely, benthic-based models under the moderate and extreme scenarios are less consistent between modeling frameworks and their estimations diverge substantially, impeding accurate interpretations. Surface-derived models estimated substantial losses of abiotically suitable areas for queen conch (i.e., areas projected to transition to abiotic conditions that fall outside of the suitable conditions defined by the recorded occurrences of the species), projecting abrupt declines from 2020–2040 across all climate change scenarios. This work aims to enhance existing knowledge about the abiotic suitability of several areas in the Western Atlantic for queen conch and provide relevant insights about the potential changes in the geographic distribution of the species over the next decades. Ultimately, anticipating future habitat availability will be key for guiding the conservation and management of this economically and ecologically critical species.

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