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 – in process]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23894510?dopt=Abstract

Identifying preservation and restoration priority areas for desert fishes in an increasingly invaded world.

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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

Genomic resource development for shellfish of conservation concern.

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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

Effects of the herbicide imazapyr on juvenile Oregon spotted frogs.

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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

Pesticides in urban streams and early life stages of Pacific coho salmon.

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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]

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Meiotic maps of sockeye salmon derived from massively parallel DNA sequencing.

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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]

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Efficacy, fate, and potential effects on salmonids of mosquito larvicides in catch basins in Seattle, Washington.

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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]

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Evidence for an amoeba-like infectious stage of Ichthyophonus sp. and description of a circulating blood stage: a probable mechanism for dispersal within the fish host.

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Evidence for an amoeba-like infectious stage of Ichthyophonus sp. and description of a circulating blood stage: a probable mechanism for dispersal within the fish host.

J Parasitol. 2013 Apr;99(2):235-40

Authors: Kocan R, LaPatra S, Hershberger P

Abstract
Small amoeboid cells, believed to be the infectious stage of Ichthyophonus sp., were observed in the bolus (stomach contents) and tunica propria (stomach wall) of Pacific staghorn sculpins and rainbow trout shortly after they ingested Ichthyophonus sp.-infected tissues. By 24-48 hr post-exposure (PE) the parasite morphed from the classically reported multinucleate thick walled schizonts to 2 distinct cell types, i.e., a larger multinucleate amoeboid cell surrounded by a narrow translucent zone and a smaller spherical cell surrounded by a “halo” and resembling a small schizont. Both cell types also appeared in the tunica propria, indicating that they had recently penetrated the columnar epithelium of the stomach. No Ichthyophonus sp. pseudo-hyphae (“germination tubes”) were observed in the bolus or penetrating the stomach wall. Simultaneously, Ichthyophonus sp. was isolated in vitro from aortic blood, which was consistently positive from 6 to 144 hr PE, then only intermittently for the next 4 wk. Small PAS-positive cells observed in blood cultures grew into colonies consisting of non-septate tubules (pseudo-hyphae) terminating in multinucleated knob-like apices similar to those seen in organ explant cultures. Organ explants were culture positive every day; however, typical Ichthyophonus sp. schizonts were not observed histologically until 20-25 days PE. From 20 to 60 days PE, schizont diameter increased from ≤ 25 μm to ≥ 82 μm. Based on the data presented herein, we are confident that we have resolved the life cycle of Ichthyophonus sp. within the piscivorous host.

PMID: 22924915 [PubMed – indexed for MEDLINE]

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Pesticides in Urban Streams and Prespawn Mortality of Pacific Coho Salmon.

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Pesticides in Urban Streams and Prespawn Mortality of Pacific Coho Salmon.

Arch Environ Contam Toxicol. 2013 Jun 7;

Authors: King KA, Grue CE, Grassley JM, Hearsey JW

Abstract
The listing of several runs of Pacific salmon as threatened or endangered and associated federal, state, and local efforts to restore/enhance salmon habitat in the Pacific Northwest make it imperative that the factors associated with these population declines are understood. Prespawn mortality (PSM) has been documented in coho salmon (Oncorhynchus kisutch) within urban streams in western Washington since the late 1990s and is characterized by a suite of neurological and respiratory symptoms with mortality occurring shortly thereafter. Mortality rates in returning adults have ranged between 17 and 100 %. The cause of PSM is not known, but the presence of pesticide residues within urban streams led to a hypothesis that PSM in coho salmon and pesticides in urban streams were linked. We exposed pairs of “green” (unripe) prespawn male and female coho salmon to a pesticide mixture (“cocktail”) reported in urban streams in western Washington State, USA. Longevity, ripening in female salmon, and brain acetylcholinesterase were not significantly affected by continuous exposure to the maximum reported concentrations of the pesticides. Fertilization, hatching success, and growth of fry were also not affected when green adults were exposed to these concentrations for 96 h. The absence of effects suggests it is unlikely that pesticides within stormwater are singularly responsible for PSM in coho salmon or that they impair the reproductive capability of exposed adults.

PMID: 23744049 [PubMed – as supplied by publisher]

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