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Institution

Inter-American Tropical Tuna Commission

OtherLa Jolla, California, United States
About: Inter-American Tropical Tuna Commission is a other organization based out in La Jolla, California, United States. It is known for research contribution in the topics: Tuna & Population. The organization has 96 authors who have published 336 publications receiving 18699 citations. The organization is also known as: IATTC.


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Journal ArticleDOI
TL;DR: The basic components and the underlying philosophy of ADMB are described, with an emphasis on functionality found in no other statistical software, and the main advantages are flexibility, speed, precision, stability and built-in methods to quantify uncertainty.
Abstract: Many criteria for statistical parameter estimation, such as maximum likelihood, are formulated as a nonlinear optimization problem. Automatic Differentiation Model Builder (ADMB) is a programming framework based on automatic differentiation, aimed at highly nonlinear models with a large number of parameters. The benefits of using AD are computational efficiency and high numerical accuracy, both crucial in many practical problems. We describe the basic components and the underlying philosophy of ADMB, with an emphasis on functionality found in no other statistical software. One example of such a feature is the generic implementation of Laplace approximation of high-dimensional integrals for use in latent variable models. We also review the literature in which ADMB has been used, and discuss future development of ADMB as an open source project. Overall, the main advantages of ADMB are flexibility, speed, precision, stability and built-in methods to quantify uncertainty.

1,753 citations

Journal ArticleDOI
TL;DR: In order to apply the theory developed here to the tropical tuna fishery, it will be necessary to compile statistics of catch, abundance and intensity of fishing over a considerable series of years, beginning as early in the history of the fishery as possible.

1,565 citations

Journal ArticleDOI
TL;DR: A review of the state of the art in the methods for standardizing catch and effort data can be found in this paper, which outlines the major estimation approaches being applied, how to identify and select appropriate explanatory variables, and how standardized catch rate can be used when conducting stock assessments.

1,154 citations

Journal ArticleDOI
07 Jul 2011-Nature
TL;DR: It is shown that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems, and critical habitats across multinational boundaries are identified.
Abstract: Pelagic marine predators face unprecedented challenges and uncertain futures. Overexploitation and climate variability impact the abundance and distribution of top predators in ocean ecosystems. Improved understanding of ecological patterns, evolutionary constraints and ecosystem function is critical for preventing extinctions, loss of biodiversity and disruption of ecosystem services. Recent advances in electronic tagging techniques have provided the capacity to observe the movements and long-distance migrations of animals in relation to ocean processes across a range of ecological scales. Tagging of Pacific Predators, a field programme of the Census of Marine Life, deployed 4,306 tags on 23 species in the North Pacific Ocean, resulting in a tracking data set of unprecedented scale and species diversity that covers 265,386 tracking days from 2000 to 2009. Here we report migration pathways, link ocean features to multispecies hotspots and illustrate niche partitioning within and among congener guilds. Our results indicate that the California Current large marine ecosystem and the North Pacific transition zone attract and retain a diverse assemblage of marine vertebrates. Within the California Current large marine ecosystem, several predator guilds seasonally undertake north-south migrations that may be driven by oceanic processes, species-specific thermal tolerances and shifts in prey distributions. We identify critical habitats across multinational boundaries and show that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems.

1,081 citations

Journal ArticleDOI
24 Jun 2010-Nature
TL;DR: Maximum-likelihood methods are used to test for Lévy patterns in relation to environmental gradients in the largest animal movement data set assembled for this purpose and results are consistent with the LÉvy-flight foraging hypothesis, supporting the contention that organism search strategies naturally evolved in such a way that they exploit optimal Lé Ivy patterns.
Abstract: An optimal search theory, the so-called Levy-flight foraging hypothesis1, predicts that predators should adopt search strategies known as Levy flights where prey is sparse and distributed unpredictably, but that Brownian movement is sufficiently efficient for locating abundant prey2, 3, 4. Empirical studies have generated controversy because the accuracy of statistical methods that have been used to identify Levy behaviour has recently been questioned5, 6. Consequently, whether foragers exhibit Levy flights in the wild remains unclear. Crucially, moreover, it has not been tested whether observed movement patterns across natural landscapes having different expected resource distributions conform to the theory’s central predictions. Here we use maximum-likelihood methods to test for Levy patterns in relation to environmental gradients in the largest animal movement data set assembled for this purpose. Strong support was found for Levy search patterns across 14 species of open-ocean predatory fish (sharks, tuna, billfish and ocean sunfish), with some individuals switching between Levy and Brownian movement as they traversed different habitat types. We tested the spatial occurrence of these two principal patterns and found Levy behaviour to be associated with less productive waters (sparser prey) and Brownian movements to be associated with productive shelf or convergence-front habitats (abundant prey). These results are consistent with the Levy-flight foraging hypothesis1, 7, supporting the contention8, 9 that organism search strategies naturally evolved in such a way that they exploit optimal Levy patterns.

848 citations


Authors
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20223
202118
202022
201924
201815
201732