Impacts of ocean acidification on marine seafood.

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Impacts of ocean acidification on marine seafood.

Trends Ecol Evol. 2012 Nov 1;

Authors: Branch TA, Dejoseph BM, Ray LJ, Wagner CA

Abstract
Ocean acidification is a series of chemical reactions due to increased CO(2) emissions. The resulting lower pH impairs the senses of reef fishes and reduces their survival, and might similarly impact commercially targeted fishes that produce most of the seafood eaten by humans. Shelled molluscs will also be negatively affected, whereas cephalopods and crustaceans will remain largely unscathed. Habitat changes will reduce seafood production from coral reefs, but increase production from seagrass and seaweed. Overall effects of ocean acidification on primary productivity and, hence, on food webs will result in hard-to-predict winners and losers. Although adaptation, parental effects, and evolution can mitigate some effects of ocean acidification, future seafood platters will look rather different unless CO(2) emissions are curbed.

PMID: 23122878 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/23122878?dopt=Abstract

Trade-offs in the design of fishery closures: management of silky shark bycatch in the eastern Pacific Ocean tuna fishery.

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Trade-offs in the design of fishery closures: management of silky shark bycatch in the eastern Pacific Ocean tuna fishery.

Conserv Biol. 2009 Jun;23(3):626-35

Authors: Watson JT, Essington TE, Lennert-Cody CE, Hall MA

Abstract
Bycatch–the incidental catch of nontarget species–is a principal concern in marine conservation and fisheries management. In the eastern Pacific Ocean tuna fishery, a large fraction of nonmammal bycatch is captured by purse-seine gear when nets are deployed around floating objects. We examined the spatial distribution of a dominant species in this fishery’s bycatch, the apex predator silky shark (Carcharhinus falciformis), from 1994 to 2005 to determine whether spatial closures, areas where fishing is prohibited, might effectively reduce the bycatch of this species. We then identified candidate locations for fishery closures that specifically considered the trade-off between bycatch reduction and the loss of tuna catch and evaluated ancillary conservation benefits to less commonly captured taxa. Smoothed spatial distributions of silky shark bycatch did not indicate persistent small areas of especially high bycatch for any size class of shark over the 12-year period. Nevertheless, bycatch of small silky sharks (<90 cm total length) was consistently higher north of the equator during all years. On the basis of this distribution, we evaluated nearly 100 candidate closure areas between 5°N and 15°N that could have reduced, by as much as 33%, the total silky shark bycatch while compromising only 12% of the tuna catch. Although silky sharks are the predominant species of elasmobranchs caught as bycatch in this fishery, closures also suggested reductions in the bycatch of other vulnerable taxa, including other shark species and turtles. Our technique provides an effective method with which to balance the costs and benefits of conservation in fisheries management. Spatial closures are a viable management tool, but implementation should be preceded by careful consideration of the consequences of fishing reallocation.

PMID: 19040650 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/19040650?dopt=Abstract

Pattern and process of biotic homogenization in the New Pangaea.

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Pattern and process of biotic homogenization in the New Pangaea.

Proc Biol Sci. 2012 Oct 10;

Authors: Baiser B, Olden JD, Record S, Lockwood JL, McKinney ML

Abstract
Human activities have reorganized the earth’s biota resulting in spatially disparate locales becoming more or less similar in species composition over time through the processes of biotic homogenization and biotic differentiation, respectively. Despite mounting evidence suggesting that this process may be widespread in both aquatic and terrestrial systems, past studies have predominantly focused on single taxonomic groups at a single spatial scale. Furthermore, change in pairwise similarity is itself dependent on two distinct processes, spatial turnover in species composition and changes in gradients of species richness. Most past research has failed to disentangle the effect of these two mechanisms on homogenization patterns. Here, we use recent statistical advances and collate a global database of homogenization studies (20 studies, 50 datasets) to provide the first global investigation of the homogenization process across major faunal and floral groups and elucidate the relative role of changes in species richness and turnover. We found evidence of homogenization (change in similarity ranging from -0.02 to 0.09) across nearly all taxonomic groups, spatial extent and grain sizes. Partitioning of change in pairwise similarity shows that overall change in community similarity is driven by changes in species richness. Our results show that biotic homogenization is truly a global phenomenon and put into question many of the ecological mechanisms invoked in previous studies to explain patterns of homogenization.

PMID: 23055062 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/23055062?dopt=Abstract

Characterizing short read sequencing for gene discovery and RNA-Seq analysis in Crassostrea gigas.

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Characterizing short read sequencing for gene discovery and RNA-Seq analysis in Crassostrea gigas.

Comp Biochem Physiol Part D Genomics Proteomics. 2012 Jun;7(2):94-9

Authors: Gavery MR, Roberts SB

Abstract
Advances in DNA sequencing technology have provided opportunities to produce new transcriptomic resources for species that lack completely sequenced genomes. However, there are limited examples that rely solely on ultra-short read sequencing technologies (e.g. Solexa, SOLiD) for transcript discovery and gene expression analysis (i.e. RNA-Seq). Here we use SOLiD sequencing to examine gene expression patterns in Pacific oyster (Crassostrea gigas) populations exposed to varying degrees of anthropogenic impact. Novel transcripts were identified and RNA-Seq analysis revealed several hundred differentially expressed genes. Gene enrichment analysis determined that in addition to biological processes predicted to be associated with anthropogenic influences (e.g. immune response), other processes play important roles including cell recognition and cell adhesion. To evaluate the effectiveness of restricting characterization solely to short read sequences, mapping and RNA-Seq analysis were also performed using publicly available transcriptome sequence data as a scaffold. This study demonstrates that ultra-short read sequencing technologies can effectively generate novel transcriptome information, identify differentially expressed genes, and will be important for examining environmental physiology of non-model organisms.

PMID: 22244882 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/22244882?dopt=Abstract