Reduced disease in black abalone following mass mortality: phage therapy and natural selection.

Written by

Related Articles

Reduced disease in black abalone following mass mortality: phage therapy and natural selection.

Front Microbiol. 2014;5:78

Authors: Friedman CS, Wight N, Crosson LM, Vanblaricom GR, Lafferty KD

Abstract
Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

PMID: 24672512 [PubMed]

via pubmed: school of aquatic an… http://ift.tt/1hIrQ9H

Genotyping by sequencing resolves shallow population structure to inform conservation of Chinook salmon (Oncorhynchus tshawytscha).

Written by

Genotyping by sequencing resolves shallow population structure to inform conservation of Chinook salmon (Oncorhynchus tshawytscha).

Evol Appl. 2014 Mar;7(3):355-69

Authors: Larson WA, Seeb LW, Everett MV, Waples RK, Templin WD, Seeb JE

Abstract
Recent advances in population genomics have made it possible to detect previously unidentified structure, obtain more accurate estimates of demographic parameters, and explore adaptive divergence, potentially revolutionizing the way genetic data are used to manage wild populations. Here, we identified 10 944 single-nucleotide polymorphisms using restriction-site-associated DNA (RAD) sequencing to explore population structure, demography, and adaptive divergence in five populations of Chinook salmon (Oncorhynchus tshawytscha) from western Alaska. Patterns of population structure were similar to those of past studies, but our ability to assign individuals back to their region of origin was greatly improved (>90% accuracy for all populations). We also calculated effective size with and without removing physically linked loci identified from a linkage map, a novel method for nonmodel organisms. Estimates of effective size were generally above 1000 and were biased downward when physically linked loci were not removed. Outlier tests based on genetic differentiation identified 733 loci and three genomic regions under putative selection. These markers and genomic regions are excellent candidates for future research and can be used to create high-resolution panels for genetic monitoring and population assignment. This work demonstrates the utility of genomic data to inform conservation in highly exploited species with shallow population structure.

PMID: 24665338 [PubMed]

via pubmed: school of aquatic an… http://ift.tt/OZzLs2

Secondary contact and changes in coastal habitat availability influence the nonequilibrium population structure of a salmonid (Oncorhynchus keta).

Written by

Related Articles

Secondary contact and changes in coastal habitat availability influence the nonequilibrium population structure of a salmonid (Oncorhynchus keta).

Mol Ecol. 2013 Dec;22(23):5848-60

Authors: Petrou EL, Hauser L, Waples RS, Seeb JE, Templin WD, Gomez-Uchida D, Seeb LW

Abstract
Numerous empirical studies have reported lack of migration-drift equilibrium in wild populations. Determining the causes of nonequilibrium population structure is challenging because different evolutionary processes acting at a variety of spatiotemporal scales can produce similar patterns. Studies of contemporary populations in northern latitudes suggest that nonequilibrium population structure is probably caused by recent colonization of the region after the last Pleistocene ice age ended ~13,000 years ago. The chum salmon’s (Oncorhynchus keta) range was fragmented by dramatic environmental changes during the Pleistocene. We investigated the population structure of chum salmon on the North Alaska Peninsula (NAP) and, using both empirical data and simulations, evaluated the effects of colonization timing and founder population heterogeneity on patterns of genetic differentiation. We screened 161 single nucleotide polymorphisms and found evidence of nonequilibrium population structure when the slope of the isolation-by-distance relationship was examined at incremental spatial scales. In addition, simulations suggested that this pattern closely matched models of recent colonization of the NAP by secondary contact. Our results agree with geological and archaeological data indicating that the NAP was a dynamic landscape that may have been more recently colonized than during the last deglaciation because of dramatic changes in coastal hydrology over the last several thousand years.

PMID: 24118255 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://ift.tt/1gbnICP

High-throughput sequencing and pathway analysis reveal alteration of the pituitary transcriptome by 17α-ethynylestradiol (EE2) in female coho salmon, Oncorhynchus kisutch.

Written by

Related Articles

High-throughput sequencing and pathway analysis reveal alteration of the pituitary transcriptome by 17α-ethynylestradiol (EE2) in female coho salmon, Oncorhynchus kisutch.

Aquat Toxicol. 2013 Oct 15;142-143:146-63

Authors: Harding LB, Schultz IR, Goetz GW, Luckenbach JA, Young G, Goetz FW, Swanson P

Abstract
Considerable research has been done on the effects of endocrine disrupting chemicals (EDCs) on reproduction and gene expression in the brain, liver and gonads of teleost fish, but information on impacts to the pituitary gland are still limited despite its central role in regulating reproduction. The aim of this study was to further our understanding of the potential effects of natural and synthetic estrogens on the brain-pituitary-gonad axis in fish by determining the effects of 17α-ethynylestradiol (EE2) on the pituitary transcriptome. We exposed sub-adult coho salmon (Oncorhynchus kisutch) to 0 or 12 ng EE2/L for up to 6 weeks and effects on the pituitary transcriptome of females were assessed using high-throughput Illumina(®) sequencing, RNA-Seq and pathway analysis. After 1 or 6 weeks, 218 and 670 contiguous sequences (contigs) respectively, were differentially expressed in pituitaries of EE2-exposed fish relative to control. Two of the most highly up- and down-regulated contigs were luteinizing hormone β subunit (241-fold and 395-fold at 1 and 6 weeks, respectively) and follicle-stimulating hormone β subunit (-3.4-fold at 6 weeks). Additional contigs related to gonadotropin synthesis and release were differentially expressed in EE2-exposed fish relative to controls. These included contigs involved in gonadotropin releasing hormone (GNRH) and transforming growth factor-β signaling. There was an over-representation of significantly affected contigs in 33 and 18 canonical pathways at 1 and 6 weeks, respectively, including circadian rhythm signaling, calcium signaling, peroxisome proliferator-activated receptor (PPAR) signaling, PPARα/retinoid x receptor α activation, and netrin signaling. Network analysis identified potential interactions between genes involved in circadian rhythm and GNRH signaling, suggesting possible effects of EE2 on timing of reproductive events.

PMID: 24007788 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://ift.tt/1f24TgS

SAFS Students Lead Seattle’s Expanding Your Horizons Conference Workshop

Written by

Seattle’s Expanding Your Horizons mission is to inspire girls to pursue opportunities in STEM fields through exposure to role models and hands on activities. Last Saturday, SAFS students and alumni ran a conference workshop called ‘Flex Your Mussels‘. Below is an account from SAFS graduate student Mackenzie Gavery who developed and lead the workshop.

image

Last Saturday, with amazing help of Roberts Lab undergrads Jessica Blanchette and Katie Jackson as well as Anne Baxter from NOAA’s NWFSC, I led a workshop called ‘Flex Your Mussels’ for Seattle’s Expanding Your Horizons (SEYH) conference at Seattle University. The mission of SEYH is to inspire girls to pursue opportunities in STEM fields through exposure to role models and hands on activities.  The Seattle conference hosted 46 different workshops (bacteria to fireworks) and had over 400 middle school participants!!

At the Flex Your Mussels workshop the girls learned about the amazing role of bivalves as natural water filters.  They were able to dissect their own mussels and watch them filter water and yeast on their ctenidia using dissecting scopes.  They also took a close look at what the bivalves were filtering by looking at plankton samples under the microscope.

image

image

image

The girls were very curious and engaged throughout the workshop.  I think we all agreed that our favorite part of volunteering at SEYH was the curiosity and questions from the girls.  It was a really fun day and I hope we get the chance to do it again next year.

Big thanks to Jessica, Katie and Anne for being AMAZING teachers, role models as well as outstanding car packers!!

-Mackenzie Gavery

image

Diversity of movements by individual anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii.

Written by

Diversity of movements by individual anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii.

J Fish Biol. 2013 Nov;83(5):1161-82

Authors: Goetz FA, Baker B, Buehrens T, Quinn TP

Abstract
Wild, downstream-migrating cutthroat trout, Oncorhynchus clarkii clarkii, smolts and adults were captured at a weir in Big Beef Creek, Hood Canal, Washington, surgically implanted with acoustic tags and tracked to identify spring and summer movements using stationary receivers in order to test the assumption that the species moves little while in marine waters. Overall, 93-96% migrated from the stream into the east side of the long narrow fjord, where they dispersed north and south along the shoreline. Most O. c. clarkii were detected nearshore within 10 km of the release site, with declining detection rates to 77 km. Over one-third (36%) crossed c. 2-4 km of deep water to the other side but only one O. c. clarkii left the Hood Canal basin. Movements and behaviour patterns did not differ between smolts and adults but cluster analysis revealed two modes of distribution, here categorized as residents and migrants. Within these categories of overall distribution, a range of finer-scale behaviour patterns was observed, including sedentary individuals, daily moving between proximate sites and more continuous long-distance travel. Diel movement patterns varied markedly among individuals but overall activity increased near dawn, peaked around mid-day and declined but continued at night. These patterns contrast with sympatric and closely related steelhead trout, Oncorhynchus mykiss, providing new insights into the diversity of salmonid behaviour.

PMID: 24580660 [PubMed – in process]

via pubmed: school of aquatic an… http://ift.tt/1dkKEOe

Integrating scientific guidance into marine spatial planning.

Written by

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]

via pubmed: school of aquatic an… http://ift.tt/1hHkO6B

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

Written by

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]

via pubmed: school of aquatic an… http://ift.tt/1dytzgo

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

Written by

Related Articles

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]

via pubmed: school of aquatic an… http://ift.tt/1hEwnzS

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

Written by

Related Articles

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]

via pubmed: school of aquatic an… http://ift.tt/1efWQfi