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Sebastián A. Pardo

Sebastián A. Pardo
Ecology Action Centre

PhD

About

31
Publications
9,485
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521
Citations
Additional affiliations
January 2010 - April 2017
Simon Fraser University
Position
  • PhD

Publications

Publications (31)
Article
Full-text available
Sensitivity to overfishing is often estimated using simple models that depend upon life history parameters, especially for species lacking detailed biological information. Yet, there has been little exploration of how uncertainty in life history parameters can influence demographic parameter estimates and therefore fisheries management options. We...
Chapter
Elasmobranchs play critically important ecological roles throughout the world's oceans, yet in many cases, their slow life histories and interactions with fisheries makes them particularly susceptible to exploitation. Management for these species requires robust scientific input, and mathematical models are the backbone of science-based management....
Article
Full-text available
The maximum intrinsic rate of population increase (rmax) is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, rmax can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output (b) instead. This is problematic as it effectively as...
Article
Full-text available
Devil rays (Mobula spp.) face intensifying fishing pressure to meet the ongoing international demand for gill plates. The paucity of information on growth, mortality, and fishing effort for devil rays make quantifying population growth rates and extinction risk challenging. Furthermore, unlike manta rays (Manta spp.), devil rays have not been liste...
Article
Full-text available
1. Somatic growth is a fundamental property of living organisms, and is of particular importance for species with indeterminate growth that can change in size continuously throughout their life. For example, fishes can increase in size by 2–6 orders of magnitude during their lifetime, resulting in changes in production, consumption and function at...
Article
Full-text available
A curated database of shark and ray biological data is increasingly necessary both to support fisheries management and conservation efforts, and to test the generality of hypotheses of vertebrate macroecology and macroevolution. Sharks and rays are one of the most charismatic, evolutionary distinct, and threatened lineages of vertebrates, comprisin...
Article
Spatial and temporal synchrony in abundance or survival trends can be indicative of whether populations are affected by common environmental drivers. In Atlantic salmon (Salmo salar L.), return rates to natal rivers have generally been assumed to be affected primarily by shared oceanic conditions, leading to spatially synchronous trends in mortalit...
Article
Declines in wild Atlantic salmon (Salmo salar) abundance throughout the north Atlantic are primarily attributed to decreases in survival at sea. However, comparing trends in marine survival among populations is challenging as data on both migrating smolts and returning adults are sparse and models are difficult to parameterize due to their varied l...
Preprint
Full-text available
An important challenge in ecology is to understand variation in species' maximum intrinsic rate of population increase, r max , not least because r max underpins our understanding of the limits of fishing, recovery potential, and ultimately extinction risk. Across many vertebrates, terrestrial and aquatic, body mass and environmental temperature ac...
Technical Report
Full-text available
The Chilean Angelshark (Squatina armata) is a medium-sized (to 150 cm total length) shark that occurs in the Southeast Pacific from Colombia to the Strait of Magellan, Chile. It is demersal on the continental shelf from the surf zone to 400 m depth. It may overlap in distribution with the Pacific Angelshark (S. californica) and hence there is uncer...
Article
Full-text available
The marine phase of anadromous Atlantic salmon (Salmo salar) is the least known yet one of the most crucial with regards to population persistence. Recently, declines in many salmon populations in eastern Canada have been attributed to changes in the conditions at sea, thus reducing their survival. However, marine survival estimates are difficult t...
Article
Iteroparity is a bet-hedging strategy where individuals spread the risk of reproductive failure over time. The occurrence of iteroparity (i.e. proportion of repeat spawners in annual returns) varies among Atlantic salmon (Salmo salar) populations, yet information on its ecological importance is limited. We compiled multi-decadal time series on the...
Article
Full-text available
There is recent evidence of widespread declines of shovelnose ray populations (Order Rhinopristiformes) in heavily fished regions. These declines, which are likely driven by high demand for their fins in Asian markets, raises concern about their risk of over-exploitation and extinction. Using life-history theory and incorporating uncertainty into a...
Preprint
Full-text available
Recent evidence of widespread and rapid declines of shovelnose ray populations (Order Rhinopristiformes), driven by a high demand for their fins in Asian markets and the quality of their flesh, raises concern about their risk of over-exploitation and extinction. Using life history theory and incorporating uncertainty into a modified Euler-Lotka mod...
Article
Full-text available
Fish gill surface area varies across species and with respect to ecological lifestyles. The majority of previous studies only qualitatively describe gill surface area in relation to ecology and focus primarily on teleosts. Here, we quantitatively examined the relationship of gill surface area with respect to specific ecological lifestyle traits in...
Preprint
Full-text available
The maximum intrinsic rate of population increase r max is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, r max can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output b instead. This is problematic as it effectively assu...
Preprint
Devil rays ( Mobula spp.) face rapidly intensifying fishing pressure to meet the ongoing international trade and demand for their gill plates. This has been exacerbated by trade regulation of manta ray gill plates following their 2014 CITES listing. Furthermore, the paucity of information on growth, mortality, and fishing effort for devil rays make...
Article
Full-text available
The partitioning of dietary resources is a potential mechanism by which competing species can coexist. We examined local-scale dietary partitioning among 3 sympatric stingrays, Neotrygon kuhlii, Dasyatis fluviorum and Himantura toshi, from an intertidal flat in Moreton Bay, Australia, and compared their diets to the benthic prey items at the site....
Article
Full-text available
Background. The directed harvest and global trade in the gill plates of mantas, and devil rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place t...
Preprint
Full-text available
The directed harvest and global trade in the gill plates of mantas, and other mobulid rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their...
Preprint
The directed harvest and global trade in the gill plates of mantas, and other mobulid rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their...
Article
Full-text available
Fisheries bycatch threatens populations of marine megafauna such as marine mammals, turtles, seabirds, sharks and rays, but fisheries impacts on non-target populations are often difficult to assess due to factors such as data limitation, poorly defined management objectives and lack of quantitative bycatch reduction targets. Limit reference points...
Technical Report
Full-text available
This document describes available techniques for the assessment of the status of bycatch species. For all the approaches discussed, we provide data requirements, caveats, assumptions, recommendations, and comments on their accuracy and precision, when available. First, we review the direct (i.e., based on catch data) and indirect methods (i.e., bas...
Conference Paper
Full-text available
Growth is a fundamental property of living organisms, and is of particular importance in marine ecosystems where an individual’s size can increase numerous orders of magnitude during their lifetime, and determines the niche they occupy in the ecosystem. Quantifying growth rates allows the calculation of parameters which are important in demographic...
Article
This study examined the reproduction and population structure of the blue-spotted maskray Neotrygon kuhlii within Moreton Bay, a subtropical embayment in south-east Queensland, Australia. Mean sizes at maturity were 314 mm disc width (W(D)) in females (n = 140, 115-465 mm W(D)) and 294 mm W(D) in males (n = 123, 129-381 mm W(D)). Female N. kuhlii h...

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