| Related Articles |
Environmental cost of conservation victories.
Proc Natl Acad Sci U S A. 2013 Jun 4;110(23):9187
Authors: Hilborn R
PMID: 23737497 [PubMed – in process]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23737497?dopt=Abstract
Resource competition induces heterogeneity and can increase cohort survivorship: selection-event duration matters.
Oecologia. 2013 Aug 3;
Authors: Gosselin JL, Anderson JJ
Abstract
Determining when resource competition increases survivorship can reveal processes underlying population dynamics and reinforce the importance of heterogeneity among individuals in conservation. We ran an experiment mimicking the effects of competition in a growing season on survivorship during a selection event (e.g., overwinter starvation, drought). Using a model fish species (Poecilia reticulata), we studied how food availability and competition affect mass in a treatment stage, and subsequently survivorship in a challenge stage of increased temperature and starvation. The post-treatment mean mass was strongly related to the mean time to mortality and mass at mortality at all levels of competition. However, competition increased variance in mass and extended the right tail of the survivorship curve, resulting in a greater number of individuals alive beyond a critical temporal threshold ([Formula: see text]) than without competition. To realize the benefits from previously experienced competition, the duration of the challenge ([Formula: see text]) following the competition must exceed the critical threshold [Formula: see text] (i.e., competition increases survivorship when [Formula: see text]). Furthermore, this benefit was equivalent to increasing food availability by 20 % in a group without competition in our experiment. The relationship of [Formula: see text] to treatment and challenge conditions was modeled by characterizing mortality through mass loss in terms of the stochastic rate of loss of vitality (individual’s survival capacity). In essence, when the duration of a selection event exceeds [Formula: see text], competition-induced heterogeneity buffers against mortality through overcompensation processes among individuals of a cohort. Overall, our study demonstrates an approach to quantify how early life stage heterogeneity affects survivorship.
PMID: 23912261 [PubMed – as supplied by publisher]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23912261?dopt=Abstract
| 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 – in process]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23894510?dopt=Abstract
| Related Articles |
Identifying preservation and restoration priority areas for desert fishes in an increasingly invaded world.
Environ Manage. 2013 Mar;51(3):631-41
Authors: Pool TK, Strecker AL, Olden JD
Abstract
A commonly overlooked aspect of conservation planning assessments is that wildlife managers are increasingly focused on habitats that contain non-native species. We examine this management challenge in the Gila River basin (150,730 km(2)), and present a new planning strategy for fish conservation. By applying a hierarchical prioritization algorithm to >850,000 fish records in 27,181 sub-watersheds we first identified high priority areas (PAs) termed “preservation PAs” with high native fish richness and low non-native richness; these represent traditional conservation targets. Second, we identified “restoration PAs” with high native fish richness that also contained high numbers of non-native species; these represent less traditional conservation targets. The top 10 % of preservation and restoration PAs contained common native species (e.g., Catostomus clarkii, desert sucker; Catostomus insignis, Sonora sucker) in addition to native species with limited distributions (i.e., Xyrauchen texanus, razorback sucker; Oncorhynchus gilae apache, Apache trout). The top preservation and restoration PAs overlapped by 42 %, indicating areas with high native fish richness range from minimally to highly invaded. Areas exclusively identified as restoration PAs also encompassed a greater percentage of native species ranges than would be expected by the random addition of an equivalent basin area. Restoration PAs identified an additional 19.0 and 26.6 % of the total ranges of two federally endangered species-Meda fulgida (spikedace) and Gila intermedia (Gila chub), respectively, compared to top preservation PAs alone-despite adding only 5.8 % of basin area. We contend that in addition to preservation PAs, restoration PAs are well suited for complementary management activities benefiting native fishes.
PMID: 23354872 [PubMed – indexed for MEDLINE]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23354872?dopt=Abstract
| Related Articles |
Genomic resource development for shellfish of conservation concern.
Mol Ecol Resour. 2013 Mar;13(2):295-305
Authors: Timmins-Schiffman EB, Friedman CS, Metzger DC, White SJ, Roberts SB
Abstract
Effective conservation of threatened species depends on the ability to assess organism physiology and population demography. To develop genomic resources to better understand the dynamics of two ecologically vulnerable species in the Pacific Northwest of the United States, larval transcriptomes were sequenced for the pinto abalone, Haliotis kamtschatkana kamtschatkana, and the Olympia oyster, Ostrea lurida. Based on comparative species analysis the Ostrea lurida transcriptome (41 136 contigs) is relatively complete. These transcriptomes represent the first significant contribution to genomic resources for both species. Genes are described based on biological function with particular attention to those associated with temperature change, oxidative stress and immune function. In addition, transcriptome-derived genetic markers are provided. Together, these resources provide valuable tools for future studies aimed at conservation of Haliotis kamtschatkana kamtschatkana, Ostrea lurida and related species.
PMID: 23280275 [PubMed – indexed for MEDLINE]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23280275?dopt=Abstract
| Related Articles |
Effects of the herbicide imazapyr on juvenile Oregon spotted frogs.
Environ Toxicol Chem. 2013 Jan;32(1):228-35
Authors: Yahnke AE, Grue CE, Hayes MP, Troiano AT
Abstract
Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5 L/ha) and high-volume (7.0 L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs.
PMID: 23147474 [PubMed – indexed for MEDLINE]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23147474?dopt=Abstract
| Related Articles |
Pesticides in urban streams and early life stages of Pacific coho salmon.
Environ Toxicol Chem. 2013 Apr;32(4):920-31
Authors: King KA, Grue CE, Grassley JM, Fisk RJ
Abstract
Pesticides are frequently detected in urban streams and are believed to be primarily the result of homeowner use. Although concentrations in most cases are low (<1 µg/L), there is concern that pesticide inputs threaten efforts to restore and enhance salmon habitat. The authors exposed early life stages of coho salmon (Oncorhynchus kisutch) to a pesticide mixture (“cocktail”) representative of those pesticides most frequently reported in urban streams in western Washington State, USA. Life stages were continuously exposed to pulses of the cocktail simulating those in urban streams in fall and winter when coho salmon eggs and sac fry are present. Nominal concentrations of eight herbicides, two insecticides, a fungicide, and a breakdown product were the maximum detected. Fertilization, hatching success, survival, deformities, and growth of fry were not significantly affected. A reduction in fertilization success (19-25%) was not reproducible even when gametes were exposed to 100 times the maximum concentrations detected. Based on the end points examined in the present study, the results suggest that direct exposure to the pesticides most frequently detected in urban streams in western Washington does not impair early life stages of coho salmon and is not a major factor governing the recovery of salmon populations. The extent to which pesticide exposure would affect smoltification, outmigration, and ocean survival needs to be determined.
PMID: 23297254 [PubMed – indexed for MEDLINE]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23297254?dopt=Abstract
| Related Articles |
Meiotic maps of sockeye salmon derived from massively parallel DNA sequencing.
BMC Genomics. 2012;13:521
Authors: Everett MV, Miller MR, Seeb JE
Abstract
BACKGROUND: Meiotic maps are a key tool for comparative genomics and association mapping studies. Next-generation sequencing and genotyping by sequencing are speeding the processes of SNP discovery and the development of new genetic tools, including meiotic maps for numerous species. Currently there are limited genetic resources for sockeye salmon, Oncorhynchus nerka. We develop the first dense meiotic map for sockeye salmon using a combination of novel SNPs found in restriction site associated DNA (RAD tags) and SNPs available from existing expressed sequence tag (EST) based assays.
RESULTS: We discovered and genotyped putative SNPs in 3,430 RAD tags. We removed paralogous sequence variants leaving 1,672 SNPs; these were combined with 53 EST-based SNP genotypes for linkage mapping. The map contained 29 male and female linkage groups, consistent with the haploid chromosome number expected for sockeye salmon. The female map contains 1,057 loci spanning 4,896 cM, and the male map contains 1,118 loci spanning 4,220 cM. Regions of conservation with rainbow trout and synteny between the RAD based rainbow trout map and the sockeye salmon map were established.
CONCLUSIONS: Using RAD sequencing and EST-based SNP assays we successfully generated the first high density linkage map for sockeye salmon.
PMID: 23031582 [PubMed – indexed for MEDLINE]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23031582?dopt=Abstract
Efficacy, fate, and potential effects on salmonids of mosquito larvicides in catch basins in Seattle, Washington.
J Am Mosq Control Assoc. 2012 Sep;28(3):206-18
Authors: Sternberg M, Grue C, Conquest L, Grassley J, King K
Abstract
We investigated the efficacy, fate, and potential for direct effects on salmonids of 4 common mosquito larvicides (Mosquito Dunks and Bits (AI: Bacillis thuringiensis var. israelensis, [Bti]), VectoLex WSP (AI: Bacillus sphaericus [Bs], VectoLex CG [AI: Bs], and Altosid Briquets [AI: s-methoprene]) in Seattle, WA, during 3 summers. During efficacy trials in 2006, all treatments resulted in a rapid reduction in number of mosquito pupae (Mosquito Dunks and Bits and VectoLex WSP) or emergence success (Altosid Briquets). VectoLex CG was chosen for city-wide application in 2007 and 2008. The average counts of pupae within round-top basins remained significantly below the control average for 11 wk in 2007, whereas efficacy in grated-top basins was short-lived. In 2008 the average counts of pupae within grated-top basins remained significantly below the control average for 10 wk. Altosid XR was also effective in reducing adult emergence within grated basins in 2008. In 2007 and 2008, frequent precipitation events made the evaluation of efficacy difficult due to reductions in pupae across control and treated basins. Four separate analyses of VectoLex products revealed that the product was a combination of Bs and Bti. Both Bs and Bti were detected in 3 urban creeks connected to treated basins in 2007 and 2008. Laboratory toxicity test results suggest that concentrations of Bs and Bti detected in each of the watersheds pose little direct hazard to juvenile salmonids.
PMID: 23833901 [PubMed – in process]
via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23833901?dopt=Abstract
Could recent declines in Puget Sound herring be linked to decreases in native eelgrass? Biologist Tessa Francis reports on a new study that may provide insight into the health of one of the region’s most iconic forage fish.