Integrating scientific guidance into marine spatial planning.

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Integrating scientific guidance into marine spatial planning.

Proc Biol Sci. 2014;281(1781):20132252

Authors: Rassweiler A, Costello C, Hilborn R, Siegel DA

Abstract
Marine spatial planning (MSP), whereby areas of the ocean are zoned for different uses, has great potential to reduce or eliminate conflicts between competing management goals, but only if strategically applied. The recent literature overwhelmingly agrees that including stakeholders in these planning processes is critical to success; but, given the countless alternative ways even simple spatial regulations can be configured, how likely is it that a stakeholder-driven process will generate plans that deliver on the promise of MSP? Here, we use a spatially explicit, dynamic bioeconomic model to show that stakeholder-generated plans are doomed to fail in the absence of strong scientific guidance. While strategically placed spatial regulations can improve outcomes remarkably, the vast majority of possible plans fail to achieve this potential. Surprisingly, existing scientific rules of thumb do little to improve outcomes. Here, we develop an alternative approach in which models are used to identify efficient plans, which are then modified by stakeholders. Even if stakeholders alter these initial proposals considerably, results hugely outperform plans guided by scientific rules of thumb. Our results underscore the importance of spatially explicit dynamic models for the management of marine resources and illustrate how such models can be harmoniously integrated into a stakeholder-driven MSP process.

PMID: 24573841 [PubMed – in process]

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Evolution of age and length at maturation of Alaskan salmon under size-selective harvest.

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Evolution of age and length at maturation of Alaskan salmon under size-selective harvest.

Evol Appl. 2014 Feb;7(2):313-22

Authors: Kendall NW, Dieckmann U, Heino M, Punt AE, Quinn TP

Abstract
Spatial and temporal trends and variation in life-history traits, including age and length at maturation, can be influenced by environmental and anthropogenic processes, including size-selective exploitation. Spawning adults in many wild Alaskan sockeye salmon populations have become shorter at a given age over the past half-century, but their age composition has not changed. These fish have been exploited by a gillnet fishery since the late 1800s that has tended to remove the larger fish. Using a rare, long-term dataset, we estimated probabilistic maturation reaction norms (PMRNs) for males and females in nine populations in two basins and correlated these changes with fishery size selection and intensity to determine whether such selection contributed to microevolutionary changes in maturation length. PMRN midpoints decreased in six of nine populations for both sexes, consistent with the harvest. These results support the hypothesis that environmental changes in the ocean (likely from competition) combined with adaptive microevolution (decreased PMRNs) have produced the observed life-history patterns. PMRNs did not decrease in all populations, and we documented differences in magnitude and consistency of size selection and exploitation rates among populations. Incorporating evolutionary considerations and tracking further changes in life-history traits can support continued sustainable exploitation and productivity in these and other exploited natural resources.

PMID: 24567750 [PubMed]

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Genetic and morphometric divergence in threespine stickleback in the Chignik catchment, Alaska.

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Genetic and morphometric divergence in threespine stickleback in the Chignik catchment, Alaska.

Ecol Evol. 2014 Jan;4(2):144-56

Authors: Taugbøl A, Junge C, Quinn TP, Herland A, Vøllestad LA

Abstract
Divergent selection pressures induced by different environmental conditions typically lead to variation in life history, behavior, and morphology. When populations are locally adapted to their current environment, selection may limit movement into novel sites, leading to neutral and adaptive genetic divergence in allopatric populations. Subsequently, divergence can be reinforced by development of pre-or postzygotic barriers to gene flow. The threespine stickleback, Gasterosteus aculeatus, is a primarily marine fish that has invaded freshwater repeatedly in postglacial times. After invasion, the established freshwater populations typically show rapid diversification of several traits as they become reproductively isolated from their ancestral marine population. In this study, we examine the genetic and morphometric differentiation between sticklebacks living in an open system comprising a brackish water lagoon, two freshwater lakes, and connecting rivers. By applying a set of microsatellite markers, we disentangled the genetic relationship of the individuals across the diverse environments and identified two genetic populations: one associated with brackish and the other with the freshwater environments. The “brackish” sticklebacks were larger and had a different body shape than those in freshwater. However, we found evidence for upstream migration from the brackish lagoon into the freshwater environments, as fish that were genetically and morphometrically similar to the lagoon fish were found in all freshwater sampling sites. Regardless, few F1-hybrids were identified, and it therefore appears that some pre-and/or postzygotic barriers to gene flow rather than geographic distance are causing the divergence in this system.

PMID: 24558570 [PubMed]

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Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

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Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

PLoS One. 2013;8(7):e69615

Authors: Baker MR, Swanson P, Young G

Abstract
Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.

PMID: 23894510 [PubMed – indexed for MEDLINE]

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Fish species introductions provide novel insights into the patterns and drivers of phylogenetic structure in freshwaters.

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Fish species introductions provide novel insights into the patterns and drivers of phylogenetic structure in freshwaters.

Proc Biol Sci. 2014;281(1778):20133003

Authors: Strecker AL, Olden JD

Abstract
Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin’s naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species.

PMID: 24452027 [PubMed – in process]

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Gyrodactylid Ectoparasites in a Population of Rainbow Trout (Oncorhynchus mykiss).

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Gyrodactylid Ectoparasites in a Population of Rainbow Trout (Oncorhynchus mykiss).

J Am Assoc Lab Anim Sci. 2014;53(1):92-7

Authors: Garcia RL, Hansen AG, Chan MM, Sanders GE

Abstract
A colony of rainbow trout (Oncorhynchus mykiss) in a decentralized aquatic animal facility was noted to have an increase in morbidity and mortality (from 4 or 5 fish each month to 3 or 4 fish daily) approximately 2 wk after experimental procedures began. The primary clinical signs were erratic swimming behavior and ‘flashing’ of fish against surfaces within housing enclosures. Moribund and normal rainbow trout were presented alive for diagnostic evaluation; samples of water from housing enclosures were provided for water quality assessment. The trout were determined to be infected with gyrodactylids, a common monogenean ectoparasite of the skin and gills in both marine and freshwater fish. This case report describes the diagnosis, pathology, and treatment of gyrodactylids and husbandry modifications associated with the resolution of this clinical aquatic-animal case.

PMID: 24411786 [PubMed – in process]

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Opportunistic exploitation: an overlooked pathway to extinction.

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Opportunistic exploitation: an overlooked pathway to extinction.

Trends Ecol Evol. 2013 Jul;28(7):409-13

Authors: Branch TA, Lobo AS, Purcell SW

Abstract
How can species be exploited economically to extinction? Past single-species hypotheses examining the economic plausibility of exploiting rare species have argued that the escalating value of rarity allows extinction to be profitable. We describe an alternative pathway toward extinction in multispecies exploitation systems, termed ‘opportunistic exploitation’. In this mode, highly valued species that are targeted first by fishing, hunting, and logging become rare, but their populations can decline further through opportunistic exploitation while more common but less desirable species are targeted. Effectively, expanding exploitation to more species subsidizes the eventual extinction of valuable species at low densities. Managers need to recognize conditions that permit opportunistic depletion and pass regulations to protect highly desirable species when exploitation can expand to other species.

PMID: 23562732 [PubMed – indexed for MEDLINE]

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Species- and community-level responses combine to drive phenology of lake phytoplankton.

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Species- and community-level responses combine to drive phenology of lake phytoplankton.

Ecology. 2013 Oct;94(10):2188-94

Authors: Walters AW, González Sagrario Mde L, Schindler DE

Abstract
Global change is leading to shifts in the seasonal timing of growth and maturation for primary producers. Remote sensing is increasingly used to measure the timing of primary production in both aquatic and terrestrial ecosystems, but there is often a poor correlation between these results and direct observations of life-history responses of individual species. One explanation may be that, in addition to phenological shifts, global change is also causing shifts in community composition among species with different seasonal timing of growth and maturation. We quantified how shifts in species phenology and in community composition translated into phenological change in a diverse phytoplankton community from 1962 to 2000. During this time, the aggregate community spring-summer phytoplankton peak has shifted 63 days earlier. The mean taxon shift was only 3 days earlier, and shifts in taxa phenology explained only 40% of the observed community phenological shift. The remaining community shift was attributed to dominant early-season taxa increasing in abundance while a dominant late-season taxon decreased in abundance. In diverse producer communities experiencing multiple stressors, changes in species composition must be considered to fully understand and predict shifts in the seasonal timing of primary production.

PMID: 24358705 [PubMed – in process]

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Proposed changes to the nomenclature of Ichthyophonus sp. life stages and structures.

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Proposed changes to the nomenclature of Ichthyophonus sp. life stages and structures.

J Parasitol. 2013 Oct;99(5):906-9

Authors: Kocan RM

Abstract
Much of the terminology describing Ichthyophonus sp. life stages and structures can be traced to the mistaken classification of this organism as a fungus. This misidentification led early investigators to use mycological terms for the structures they observed; while some terminology is not so easily explained, it appears to have been co-opted from the fields of botany and bacteriology. The purpose of this exercise is to attempt to standardize the terminology associated with Ichthyophonus and to bring it into agreement with terminology currently used to define similar life stages of other protists. The proposed changes are (1) spore/macrospore/mother spore to “schizont,” (2) microspore/endospore to “merozoite,” and (3) pseudohyphae to “hyphae” or “germ tube.”

PMID: 23617800 [PubMed – in process]

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