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Abstract Historical information has provided key insights into long‐term ecological change to marine species and ecosystems, with value to fisheries. Yet, pathways to integrate these diverse data sources into fisheries decision‐making have not been clear. Here, we identify an array of biological, ecological, and social information suitable for contemporary science‐based decision‐making, derived from local ecological knowledge, historical archives, archaeological middens and palaeoecological material. We outline two broad pathways to integrate these historical data into fisheries decision‐making, demonstrating that data‐driven use of historical information is relevant across a range of management contexts. First, historical information can inform fisheries assessments that range from simple to complex, affecting indicators of stock status. Second, it can inform estimates of biological potential and social preference, affecting the choice of fisheries reference points. Using the Caribbean Sea as an example, we illustrate these ideas with case studies representing diverse species and historical data types. Integrating historical data can improve indicators of the current state of fish populations and result in management decisions based on a more complete understanding of a potential range of variation, avoiding shifted baselines. The urgency of this work is underscored by accelerating environmental changes and the rapid loss of invaluable historical information sources. By illuminating pathways, our goal is to increase the accessibility of these types of information and to underscore that scientists, managers, and resource users have roles to play in identifying and integrating relevant long‐term data at various spatial and temporal scales to sustainably manage marine fisheries. 

Abstract Near-time conservation palaeobiology uses palaeontological, archaeological and other geohistorical records to study the late Quaternary transition of the biosphere from its pristine past to its present-day, human-altered state. Given the scarcity of data on recent extinctions in the oceans, geohistorical records are critical for documenting human-driven extinctions and extinction threats in the marine realm. The historical perspective can provide two key insights. First, geohistorical records archive the state of pre-industrial oceans at local, regional and global scales, thus enabling the detection of recent extinctions and extirpations as well as shifts in species distribution, abundance, body size and ecosystem function. Second, we can untangle the contributions of natural and anthropogenic processes by documenting centennial-to-millennial changes in the composition and diversity of marine ecosystems before and after the onset of major human impacts. This long-term perspective identifies recently emerging patterns and processes that are unprecedented, thus allowing us to better assess human threats to marine biodiversity. Although global-scale extinctions are not well documented for brackish and marine invertebrates, geohistorical studies point to numerous extirpations, declines in ecosystem functions, increases in range fragmentation and dwindling abundance of previously widespread species, indicating that marine ecosystems are accumulating a human-driven extinction debt. 

Marine habitats are in decline due to increasing anthropogenic pressures, but baseline data on species distributions needed to manage and conserve populations are lacking. Incorporating death assemblages into species assessments can create a more accurate understanding of pre-anthropogenic communities than survey records alone. In this study, we conducted a live-dead analysis on mollusks from a new 2008-2018 dredge survey in the eastern Gulf of Mexico. We selected the predatory banded tulip snail, Cinctura hunteria, as a test case for assessment because this species is one of several designated by the Florida Fish and Wildlife as a species of concern. Using spatial count data for shells in our samples, we estimated density values for each taxonomic grade over the sampled area using IDW spatial interpolation. These maps reveal large areas of occupation across the west Florida shelf for two taxonomic grades of dead shells but loss of offshore occurrence for live records. One explanation for the lack of occurrences in offshore habitats is that, unlike dead shell records, there is no time averaging accumulation of live shells. Time averaging increases detectability of species in habitats where they are rare. However, independent fisheries data from live-only animal surveys not only mirror our live-dead results but suggest that habitat loss in our live-dead comparisons was rapid and occurred in the late 1980s or early 1990s. Thus, live-dead comparisons reveal both natural baselines as well as anthropogenic changes in distribution without being significantly distorted by time-averaging biases. Including live-dead data can greatly improve species assessments when long-term survey records are unavailable and provide a key tool in combatting biodiversity loss across marine ecosystems. 

This talk will describe the work of the CPN Pre-Impact Baselines Working Group to leverage the wealth of paleoecological and historical ecological data to facilitate estimation of pre-impact species distribution baselines. Species conservation has long focused on preventing human-driven extinctions, and over the past 50 years conservation success has been measured using changes in species’ extinction risk. However, recently calls have been made for a parallel focus on species recovery, and on developing metrics with which to assess its achievement. This call to action within the conservation community is fuelled in part by the recognition that baselines of species abundance and distribution have shifted dramatically across human generations with globally detectable human impacts on ecosystems beginning at least several thousand years ago. While assessment of extinction risk generally only considers species’ change over the past few decades, assessment of recovery requires considering change over centuries to millennia. This requires identifying the baseline status at the time when humans first became a major factor influencing the abundance and distribution of a species. Two new frameworks for considering conservation status relative to a species’ pre-impact baseline have been recently released: EPOCH (Evaluation of POpulation CHange), and the IUCN Green Status of Species. These frameworks have been lauded as moving conservation in a much-needed direction, but there is also concern about whether these methods will be applicable to any but a few well-known, charismatic species. Using a combination of modelling approaches, we are working to estimate species pre-impact distributions in a way that is accessible to conservation practitioners, helping to unshift the baseline and bring species recovery into the mainstream. 

Marine species assessments rely heavily on baseline surveys conducted after the 1960s, long after many anthropogenic pressures began, which could lead to misinformed management decisions and poor conservation outcomes. In this study, we collaborated with Florida Fish and Wildlife to conduct stock assessments for mollusks of the west Florida shelf that incorporate shell death assemblages. One of our first assessments was of the Florida Fighting Conch, Strombus alatus, an abundant gastropod that is also under consideration as a replacement fishery for the threatened Queen Conch. Live and dead shells were collected from >300 dredge tows between 2008-2018 covering the entire west Florida shelf. Shells were age-partitioned by 14C- and AAR-calibrated taphonomic criteria. Counts were converted to densities per m2. Inverse distance weighting interpolation of S. alatus death assemblages reveals multiple population centers along the coast and a rapid decrease in density with depth from 25-120 m. In contrast, live conchs were absent in our dredge samples from shelf depths deeper than 40 m. These differences are confirmed by single-visit occupancy methods that account for variation in detectability across the samples. Live-dead differences in spatial distribution are probably influenced by time averaging in death assemblages, which increases detectability of conchs in deeper habitats, where they may be too rare to be sampled alive. However, extirpation of offshore populations was also indicated by independent natural history collection occurrence records, which show numerous live-collected conchs from 1940-1980 but none afterwards, despite an increase in sampling effort. These results suggest that live-dead comparisons can reveal biodiversity loss at the scale of large marine ecosystems.