Timothy D. White's research while affiliated with Stanford University and other places

Publications (23)

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Variation in behavior within marine and terrestrial species can influence the functioning of the ecosystems they inhabit. However, the contribution of social behavior to ecosystem function remains underexplored. Many coral reef fish species provide potentially insightful models for exploring how social behavior shapes ecological function because th...
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Illegal, unreported, and unregulated (IUU) fishing incurs an annual cost of up to US$25 billion in economic losses, results in substantial losses of aquatic life, and has been linked to human rights violations. Vessel tracking data from the automatic identification system (AIS) are powerful tools for combating IUU, yet AIS transponders can be disab...
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Significance Global vessel traffic is increasing alongside world economic growth. The potential for rising lethal ship strikes on endangered species of marine megafauna, such as the plankton-feeding whale shark, remains poorly understood since areas of highest overlap are seldom determined across an entire species range. Here we show how satellite...
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Over the past 4 decades there has been a growing concern for the conservation status of elasmobranchs (sharks and rays). In 2002, the first elasmobranch species were added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Less than 20 yr later, there were 39 species on Appendix II and 5 o...
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Over the last two decades, satellite tagging of adult and sub-adult white sharks Carcharodon carcharias off the west coast of North America has revealed a predictable onshore-offshore migratory cycle. Our current understanding of the vertical movements exhibited by white sharks while in their coastal foraging phase in the California Current, howeve...
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106,107 ✉ replying to A. V. Harry & J. M. Braccini Nature https://doi.org/10.1038/s41586-021-03463-w (2021) Our global analysis 1 estimated the overlap and fishing exposure risk (FEI) using the space use of satellite-tracked sharks and longline fishing effort monitored by the automatic identification system (AIS). In the accompanying Comment, Harry...
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This article is a response to Murua et al.'s Matters Arising article in Nature, "Shark mortality cannot be assessed by fishery overlap alone," which arose from arising from N. Queiroz et al. Nature https://doi.org/10.1038/s41586-019-1444-4 (2019).
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Effective fisheries management requires an understanding of fisher behavior. Though vessel tracking systems are increasingly used to describe the movements and activities of industrial fishing fleets, their use has been limited within the small-scale fisheries employing the vast majority of the world's capture fishers. Here we combine novel vessel...
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Determining population trends is critical for evaluating management actions and prioritizing species protections. In this study, we used empirical data to produce an estimate of the population trend for sub-adult and adult white sharks in central California. We used the unique dorsal fin morphology to build a mark-recapture data set in a modified J...
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Silky sharks (Carcharhinus falciformis) represent a major component of global shark catch, both directly and as bycatch, and populations are declining as a result. An improved understanding of their movement ecology is needed to support conservation efforts. We deployed satellite and acoustic tags (2013-2018) and analyzed historical fisheries recor...
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Large marine protected areas (MPAs) of unprecedented size have recently been established across the global oceans, yet their ability to meet conservation objectives is debated. Key areas of debate include uncertainty over nations' abilities to enforce fishing bans across vast, remote regions and the intensity of human impacts before and after MPA i...
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One of the aims of the United Nations (UN) negotiations on the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction (ABNJ) is to develop a legal process for the establishment of area-based management tools, including marine protected areas, in ABNJ. Here we use a conservation planning algorithm to integrate...
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The U.S. Congress is currently discussing the Shark Fin Sales Elimination Act to eliminate shark fin trade at the federal level. This bill was introduced in 2017 and has been proceeding very slowly in Congress because of mixed reviews from the scientific community. Debate exists on whether shark conservation and management are effectively addressed...
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Effective ocean management and conservation of highly migratory species depends on resolving overlap between animal movements and distributions and fishing effort. Yet, this information is lacking at a global scale. Here we show, using a big-data approach combining satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of...
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Native forests on islands throughout the global tropics face increasing pressure from the human-driven expansion of coconut palm (Cocos nucifera) planted for the purposes of coconut oil harvest. Conversion from native forests to Cocos monocultures leads to drastic ecological consequences in island environments and alters terrestrial and marine food...
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Many species of sharks and some tunas are threatened by overexploitation, yet the degree of overlap between industrial fisheries and pelagic fishes remains poorly understood. Using satellite tracks from 933 industrial fishing vessels and predictive habitat models from 876 electronic tags deployed on seven shark and tuna species, we developed fishin...
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Amoroso et al. demonstrate the power of our data by estimating the high-resolution trawling footprint on seafloor habitat. Yet we argue that a coarser grid is required to understand full ecosystem impacts. Vessel tracking data allow us to estimate the footprint of human activities across a variety of scales, and the proper scale depends on the spec...
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More than half the fish in the sea As the human population has grown in recent decades, our dependence on ocean-supplied protein has rapidly increased. Kroodsma et al. took advantage of the automatic identification system installed on all industrial fishing vessels to map and quantify fishing efforts across the world (see the Perspective by Polocza...

Citations

... This same explanation could account for the number of bottles found on Aldabra from Thailand and Singapore, both of which were more than an order of magnitude more abundant in the cleanup than our predictions based on trajectory analysis. There is also significant fishing activity by vessels which may be avoiding tracking systems (Welch et al., 2022), so it is possible that these could account for some of this debris. Shipping aside, another possibility is that some waste entering the ocean from countries such as Indonesia was manufactured abroad. ...
... This approach assumes that risk increases linearly as whale density/ occurrence and pot densities increase, which is a commonly utilized assumption in various risk assessment studies (e.g., Redfern et al., 2020;Samhouri et al., 2021;Womersley et al., 2022). Here, we have also made this assumption in lieu of any established, empirical relationship between whale density, fishing effort, and entanglement risk. ...
... In many instances, several constraints still hamper the implementation of effective management strategies required to reach informed shark conservation actions, both at global and regional scales. These include: (a) the underestimation of catches, with regional fishery statistics often reporting aggregated data from various fishery sectors; (b) the lack of fishery-independent data on the abundance and distribution of shark species; (c) the scarcity of information on species ecology; and (d) the poor preparation of fishers and officials on how to identify, handle and release sharks (Cashion et al., 2019;Jorgensen et al., 2022). ...
... Shark populations are particularly vulnerable to overfishing on account of slow growth rates, late age at sexual maturity and relatively low fecundity, which makes them more prone to extinction risk than most other marine fishes (Dulvy et al., 2014). Large declines in global abundance of oceanic pelagic sharks driven by overfishing have occurred over the past half century (Pacoureau et al., 2021) as a result of substantial overlap of preferred shark habitats co-occurring with industrialised fisheries, within which fishing-induced mortality is higher where spatial overlap is greater (Queiroz et al., 2019(Queiroz et al., , 2021. ...
... Poor knowledge of shark distribution (particularly for pelagic species) in relation to active fisheries can make fisheries results difficult to interpret, especially when fisheries data is scarce or incomplete (e.g., poor observer coverage, unreported catch, etc.) (Queiroz et al., , 2021a(Queiroz et al., , 2021b. Recently, there has been increasing integration of fisheries independent information from electronic tagging studies into species stock assessment models, which has particular use for highly migratory stocks by providing fine-scale resolution and long-term movement data of populations across geo-political boundaries (Sippel et al., 2015;Carvalho et al., 2015;Coelho et al., 2020). ...
... It is also possible that the increasing rates of non-injury incidents as well as non-fatal injury incidents could be caused by the apparent increase in the number of White Sharks off California or an increase in the amount of time juvenile White Sharks are remaining at certain California beaches (Lowe et al., 2012;Anderson et al., 2021a;Anderson et al., 2021b;Kanive et al., 2021;Tanaka et al., 2021). Lowe et al. (2012) reviewed catch records and other data and concluded that the White Shark population off California may be increasing. ...
... Yet, even among fishing vessels using the same gear and operating under the same flag, substantial differences may exist (within and between years) in the selection of fishing tactics, grounds, and target species as different vessel groups respond to unique institutional and economic drivers. [43][44][45] Indeed, socioeconomic factors rather than environmental ones may be primarily responsible for observed patterns of fishing activity. 26,46 Because fleet-specific differences in target and non-target species interactions and catch efficiency may have substantial impacts on the population dynamics of pelagic resources, 47 identifying and accounting for diversity of fishing activity should be a priority for research and management. ...
... When designed and managed well, these strategies can effectively mitigate incidental catch of pelagic species of conservation concern (Gilman et al., 2019). Marine protected areas that prohibit all commercial fishing, shark sanctuaries that ban commercial fishing of sharks within entire exclusive economic zones, and dynamic fishery closures all have demonstrated promise in theory and practice to effectively reduce fishing mortality of sharks (Boerder et al., 2019;Carlisle et al., 2019;Gilman et al., 2019;Curnick et al., 2020;MacNeil et al., 2020;Pons et al., 2022). Efforts to effectively design spatial management measures often leverage information on the movements and distribution of species based on animal tracking and/or direct observation of threatened species (reviewed in Hays et al., 2019). ...
... Even within protected areas, presence of policies that positively impact imperiled species (e.g., regulating commercial fishing) and enforcement of those policies may not exist. Those policies can be effective; for example, a review of global MPAs found extremely low commercial vessel traffic in several of the protected areas (White et al., 2020). Commercial and recreational fishing activities are currently allowed in many of the MPAs in the Gulf of Mexico including the Aquatic Preserves and within Florida Keys National Marine Sanctuary (Roberts et al., 2021). ...
... The process of developing ABMTs, including MPAs, can draw on a wealth of existing work 46,47 , but will also require global-and regional-scale partnerships, coordination, and outreach 48 . It will involve developing further scientific support, ensuring equitable participation, empowering inclusion of indigenous peoples and knowledge, applying the proposed criteria for ABMTs for important areas, coordinating outreach to gain support, and, crucially, beginning to design coherent networks of MPAs and wider systems of ABMTs. ...