Estimating Historical Eastern North Pacific Blue Whale Catches Using Spatial Calling Patterns.

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Estimating Historical Eastern North Pacific Blue Whale Catches Using Spatial Calling Patterns.

PLoS One. 2014;9(6):e98974

Authors: Monnahan CC, Branch TA, Stafford KM, Ivashchenko YV, Oleson EM

Abstract
Blue whales (Balaenoptera musculus) were exploited extensively around the world and remain endangered. In the North Pacific their population structure is unclear and current status unknown, with the exception of a well-studied eastern North Pacific (ENP) population. Despite existing abundance estimates for the ENP population, it is difficult to estimate pre-exploitation abundance levels and gauge their recovery because historical catches of the ENP population are difficult to separate from catches of other populations in the North Pacific. We collated previously unreported Soviet catches and combined these with known catches to form the most current estimates of North Pacific blue whale catches. We split these conflated catches using recorded acoustic calls from throughout the North Pacific, the knowledge that the ENP population produces a different call than blue whales in the western North Pacific (WNP). The catches were split by estimating spatiotemporal occurrence of blue whales with generalized additive models fitted to acoustic call patterns, which predict the probability a catch belonged to the ENP population based on the proportion of calls of each population recorded by latitude, longitude, and month. When applied to the conflated historical catches, which totaled 9,773, we estimate that ENP blue whale catches totaled 3,411 (95% range 2,593 to 4,114) from 1905-1971, and amounted to 35% (95% range 27% to 42%) of all catches in the North Pacific. Thus most catches in the North Pacific were for WNP blue whales, totaling 6,362 (95% range 5,659 to 7,180). The uncertainty in the acoustic data influence the results substantially more than uncertainty in catch locations and dates, but the results are fairly insensitive to the ecological assumptions made in the analysis. The results of this study provide information for future studies investigating the recovery of these populations and the impact of continuing and future sources of anthropogenic mortality.

PMID: 24892427 [PubMed – as supplied by publisher]

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Migratory Movements of Pygmy Blue Whales (Balaenoptera musculus brevicauda) between Australia and Indonesia as Revealed by Satellite Telemetry.

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Migratory Movements of Pygmy Blue Whales (Balaenoptera musculus brevicauda) between Australia and Indonesia as Revealed by Satellite Telemetry.

PLoS One. 2014;9(4):e93578

Authors: Double MC, Andrews-Goff V, Jenner KC, Jenner MN, Laverick SM, Branch TA, Gales NJ

Abstract
In Australian waters during the austral summer, pygmy blue whales (Balaenoptera musculus brevicauda) occur predictably in two distinct feeding areas off western and southern Australia. As with other blue whale subspecies, outside the austral summer their distribution and movements are poorly understood. In order to describe the migratory movements of these whales, we present the satellite telemetry derived movements of eleven individuals tagged off western Australia over two years. Whales were tracked from between 8 and 308 days covering an average distance of 3,009±892 km (mean ± se; range: 832 km-14,101 km) at a rate of 21.94±0.74 km per day (0.09 km-455.80 km/day). Whales were tagged during March and April and ultimately migrated northwards post tag deployment with the exception of a single animal which remained in the vicinity of the Perth Canyon/Naturaliste Plateau for its eight day tracking period. The tagged whales travelled relatively near to the Australian coastline (100.0±1.7 km) until reaching a prominent peninsula in the north-west of the state of Western Australia (North West Cape) after which they travelled offshore (238.0±13.9 km). Whales reached the northern terminus of their migration and potential breeding grounds in Indonesian waters by June. One satellite tag relayed intermittent information to describe aspects of the southern migration from Indonesia with the animal departing around September to arrive in the subtropical frontal zone, south of western Australia in December. Throughout their migratory range, these whales are exposed to impacts associated with industry, fishing and vessel traffic. These movements therefore provide a valuable tool to industry when assessing potential interactions with pygmy blue whales and should be considered by conservation managers and regulators when mitigating impacts of development. This is particularly relevant for this species as it continues to recover from past exploitation.

PMID: 24718589 [PubMed – in process]

via pubmed: school of aquatic an… http://ift.tt/1evR9eC

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]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23562732?dopt=Abstract

Citation patterns of a controversial and high-impact paper: Worm et al. (2006) “Impacts of biodiversity loss on ocean ecosystem services”.

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Citation patterns of a controversial and high-impact paper: Worm et al. (2006) “Impacts of biodiversity loss on ocean ecosystem services”.

PLoS One. 2013;8(2):e56723

Authors: Branch TA

Abstract
Citation patterns were examined for Worm et al. 2006 (Science 314:787-790), a high-impact paper that focused on relationships between marine biodiversity and ecosystem services. This paper sparked much controversy through its projection, highlighted in the press release, that all marine fisheries would be collapsed by 2048. Analysis of 664 citing papers revealed that only a small percentage (11%) referred to the 2048 projection, while 39% referred to fisheries collapse in general, and 40% to biodiversity and ecosystem services. The 2048 projection was mentioned more often in papers published soon after the original paper, in low-impact journals, and in journals outside of fields that would be expected to focus on biodiversity. Citing papers also mentioned the 2048 projection more often if they had few authors (28% of single-author papers vs. 2% of papers with 10 or more authors). These factors suggest that the more knowledgeable the authors of citing papers were about the controversy over the 2048 projection, the less likely they were to refer to it. A noteworthy finding was that if the original authors were also involved in the citing papers, they rarely (1 of 55 papers, 2%) mentioned the 2048 projection. Thus the original authors have emphasized the broader concerns about biodiversity loss, rather than the 2048 projection, as the key result of their study.

PMID: 23437224 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23437224?dopt=Abstract

Impacts of ocean acidification on marine seafood.

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Impacts of ocean acidification on marine seafood.

Trends Ecol Evol. 2013 Mar;28(3):178-86

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 – indexed for MEDLINE]

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

Opportunistic exploitation: an overlooked pathway to extinction.

Written by

Opportunistic exploitation: an overlooked pathway to extinction.

Trends Ecol Evol. 2013 Apr 4;

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 – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23562732?dopt=Abstract

Citation patterns of a controversial and high-impact paper: worm et Al. (2006) “impacts of biodiversity loss on ocean ecosystem services”.

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Citation patterns of a controversial and high-impact paper: worm et Al. (2006) “impacts of biodiversity loss on ocean ecosystem services”.

PLoS One. 2013;8(2):e56723

Authors: Branch TA

Abstract
Citation patterns were examined for Worm et al. 2006 (Science 314∶787-790), a high-impact paper that focused on relationships between marine biodiversity and ecosystem services. This paper sparked much controversy through its projection, highlighted in the press release, that all marine fisheries would be collapsed by 2048. Analysis of 664 citing papers revealed that only a small percentage (11%) referred to the 2048 projection, while 39% referred to fisheries collapse in general, and 40% to biodiversity and ecosystem services. The 2048 projection was mentioned more often in papers published soon after the original paper, in low-impact journals, and in journals outside of fields that would be expected to focus on biodiversity. Citing papers also mentioned the 2048 projection more often if they had few authors (28% of single-author papers vs. 2% of papers with 10 or more authors). These factors suggest that the more knowledgeable the authors of citing papers were about the controversy over the 2048 projection, the less likely they were to refer to it. A noteworthy finding was that if the original authors were also involved in the citing papers, they rarely (1 of 55 papers, 2%) mentioned the 2048 projection. Thus the original authors have emphasized the broader concerns about biodiversity loss, rather than the 2048 projection, as the key result of their study.

PMID: 23437224 [PubMed – in process]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/23437224?dopt=Abstract

Impacts of ocean acidification on marine seafood.

Written by

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