Identification of predators using a novel photographic tethering device

2008 ◽  
Vol 59 (12) ◽  
pp. 1079 ◽  
Author(s):  
D. K. Bassett ◽  
A. G. Jeffs ◽  
J. C. Montgomery
Keyword(s):  
Small Proportion ◽  
Spiny Lobster ◽  
Abundant Species ◽  
Fish Population ◽  
Individual Species ◽  
Aquatic Communities ◽  
Jasus Edwardsii ◽  
Pagrus Auratus ◽  
The Impact ◽  
Digital Recordings

Tethering prey is often used to help determine the impact of predators in aquatic communities. In this study, a novel photographic tethering device was used to make digital recordings of predation events on juveniles of the spiny lobster, Jasus edwardsii. Predation of lobsters was significantly higher during the day (76%) than at night (33.4%). This was consistent with a SCUBA survey that found greater numbers of diurnal predators than nocturnal predators at the study site. However, the abundance of predators was not consistent with the number of predation events for individual species as recorded by the photographic tethering device. The snapper, Pagrus auratus, was the most abundant species at the study site (45% of all diurnally active fishes), but was only responsible for 12% of predation events during the day. In contrast, wrasse species were responsible for the greatest number of predation events during the day (60%), yet made up only a small proportion of the diurnal fish population (25%). The results of this study indicate the importance of determining the identity of potential predators, through the use of a photographic tethering device, for increasing the value of results generated from tethering experiments.

scholarly journals Warming will affect phytoplankton differently: evidence through a mechanistic approach

2011 ◽  
Vol 278 (1724) ◽  
pp. 3534-3543 ◽  
Author(s):  
I. Emma Huertas ◽  
Mónica Rouco ◽  
Victoria López-Rodas ◽  
Eduardo Costas
Keyword(s):  
Phytoplankton Community ◽  
Individual Species ◽  
Aquatic Communities ◽  
Resistance Level ◽  
Increased Temperature ◽  
Species Vulnerability ◽  
Mechanistic Approach ◽  
Future Warming ◽  
Aquatic Food ◽  
The Impact

Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario.

Lobster in a bottle: a novel technique for observing the predation of juvenile spiny lobster (Jasus edwardsii)

2016 ◽  
Vol 67 (11) ◽  
pp. 1625 ◽  
Author(s):  
Jan Hesse ◽  
Jenni A. Stanley ◽  
Andrew G. Jeffs
Keyword(s):  
Spiny Lobster ◽  
Video Recording ◽  
Infrared Light ◽  
Night Time ◽  
Novel Approach ◽  
Time Period ◽  
Jasus Edwardsii ◽  
Long Time ◽  
Conger Eel ◽  
The Impact

Determining the impact of predators on juvenile spiny lobsters living on reefs is important for understanding recruitment processes that ultimately help determine the size of economically important lobster populations. The present study describes a novel approach for observing attempted predation on live juvenile spiny lobster (Jasus edwardsii) in situ, by presenting the lobster in a transparent container that was lit with infrared light to enable continuous monitoring, even at night, by video recording. This technique can be used to provide valuable information on overall relative predation pressure from comparative locations and habitats, as well as identify potential predators, their mode of predation, and the timing of their of predation activity. For example, predation attempts on juvenile J. edwardsii by the spotted wrasse (Notolabrus celidotus) were recorded only from 0500 to 1400 hours (daytime) and from 1900 to 2100 hours (dusk), whereas the activity by the northern conger eel (Conger wilsoni) was observed only for the period between 2100 and 0200 hours (nocturnal). This method of assessing predation of juvenile lobsters provides considerable advantages over previously used tethering methods, by allowing continuous observations over a long time period (≥24h), including night time, while also eliminating experimental mortality of juvenile lobsters.

The impact of seismic air gun exposure on the haemolymph physiology and nutritional condition of spiny lobster, Jasus edwardsii

2017 ◽  
Vol 125 (1-2) ◽  
pp. 146-156 ◽  
Author(s):  
Quinn P. Fitzgibbon ◽  
Ryan D. Day ◽  
Robert D. McCauley ◽  
Cedric J. Simon ◽  
Jayson M. Semmens
Keyword(s):  
Spiny Lobster ◽  
Nutritional Condition ◽  
Air Gun ◽  
Jasus Edwardsii ◽  
The Impact

Healthier lobsters in a marine reserve: effects of fishing on disease incidence in the spiny lobster, Jasus edwardsii

2009 ◽  
Vol 60 (2) ◽  
pp. 140 ◽  
Author(s):  
D. J. Freeman ◽  
A. B. MacDiarmid
Keyword(s):  
New Zealand ◽  
Bacterial Infection ◽  
Marine Protected Areas ◽  
Small Proportion ◽  
Disease Incidence ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Significant Difference ◽  
Jasus Edwardsii

Comparison of the health of spiny lobsters (Jasus edwardsii) within and adjacent to a New Zealand marine reserve revealed marked differences in the incidence of a handling-related bacterial infection. Lobsters outside the reserve were significantly more affected by tail fan necrosis than lobsters within the reserve, with up to 17% of the males caught outside the reserve over a 3-year period showing signs of tail fan necrosis, compared with less than 2% within the reserve. The incidence of tail fan necrosis changed abruptly at the marine reserve boundaries, strongly implying repeated handling as the causal agent. The incidence of tail fan necrosis in males increased up to the minimum legal size, consistent with a handling effect. Female lobsters, which comprise only a small proportion of the catch in this area, were comparatively unaffected by tail fan necrosis. There was no significant difference in the recapture rates of individuals tagged either with or without tail fan necrosis, but tagged individuals outside the reserve were more likely to develop tail fan necrosis than tagged individuals within the reserve. These findings have implications for both the dynamics of the lobster populations and their management, and highlight the role of marine protected areas in providing a baseline against which such effects of fishing can be assessed.

Immune status of the spiny lobster Jasus edwardsii with tail fan necrosis

2017 ◽  
Vol 126 (3) ◽  
pp. 229-238 ◽  
Author(s):  
H Zha ◽  
G Lewis ◽  
A Alfaro ◽  
S Wang ◽  
Y Dong ◽  
...  
Keyword(s):  
Immune Status ◽  
Spiny Lobster ◽  
Jasus Edwardsii

Do changes in reef habitats influence relative predation risk on the juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875)?

Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs
Keyword(s):  
Predation Risk ◽  
Spatial Scales ◽  
Spiny Lobster ◽  
Habitat Type ◽  
Small Spatial Scale ◽  
Important Species ◽  
Early Juvenile ◽  
Risk Of Predation ◽  
Jasus Edwardsii ◽  
Commercially Important

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.

scholarly journals 1414. #Vaccine Twitter Influencers: is it Just About Reach and Followers?

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S714-S715
Author(s):  
Jean-Etienne Poirrier ◽  
Theodore Caputi ◽  
John Ayers ◽  
Mark Dredze ◽  
Sara Poston ◽  
...  
Keyword(s):  
United States ◽  
Social Media ◽  
Standard Deviation ◽  
Small Proportion ◽  
The United States ◽  
Research Support ◽  
Policy Makers ◽  
Media Messages ◽  
Social Media Platforms ◽  
The Impact

Abstract Background A small number of powerful users (“influencers”) dominates conversations on social media platforms: less than 1% of Twitter accounts have at least 3,000 followers and even fewer have hundreds of thousands or millions of followers. Beyond simple metrics (number of tweets, retweets...) little is known about these “influencers”, particularly in relation to their role in shaping online narratives about vaccines. Our goal was to describe influential Twitter accounts that are driving conversations about vaccines and present new metrics of influence. Methods Using publicly-available data from Twitter, we selected posts from 1-Jan-2016 to 31-Dec-2018 and extracted the top 5% of accounts tweeting about vaccines with the most followers. Using automated classifiers, we determined the location of these accounts, and grouped them into those that primarily tweet pro- versus anti-vaccine content. We further characterized the demographics of these influencer accounts. Results From 25,381 vaccine-related tweets available in our sample representing 10,607 users, 530 accounts represented the top 5% by number of followers. These accounts had on average 1,608,637 followers (standard deviation=5,063,421) and 340,390 median followers. Among the accounts for which sentiment was successfully estimated by the classifier, 10.4% (n=55) posted anti-vaccine content and 33.6% (n=178) posted pro-vaccine content. Of the 55 anti-vaccine accounts, 50% (n=18) of the accounts for which location was successfully determined were from the United States. Of the 178 pro-vaccine accounts, 42.5% (n=54) were from the United States. Conclusion This study showed that only a small proportion of Twitter accounts (A) post about vaccines and (B) have a high follower count and post anti-vaccine content. Further analysis of these users may help researchers and policy makers better understand how to amplify the impact of pro-vaccine social media messages. Disclosures Jean-Etienne Poirrier, PhD, MBA, The GSK group of companies (Employee, Shareholder) Theodore Caputi, PhD, Good Analytics Inc. (Consultant) John Ayers, PhD, GSK (Grant/Research Support) Mark Dredze, PhD, Bloomberg LP (Consultant)Good Analytics (Consultant) Sara Poston, PharmD, The GlaxoSmithKline group of companies (Employee, Shareholder) Cosmina Hogea, PhD, GlaxoSmithKline (Employee, Shareholder)

Effect of fire regime on the grass community of the humid savanna of Lamto, Ivory Coast

2018 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N’Dri ◽  
Jean-Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Ivory Coast ◽  
Fire Regime ◽  
Fire Regimes ◽  
Abundant Species ◽  
Grass Species ◽  
The Third ◽  
Humid Savanna ◽  
The Impact ◽  
Tussock Grasses

AbstractThis study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

Response of dry grassland vegetation to fluctuations in weather conditions: a 9-year case study in Prague (Czech Republic)

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Jiří Dostálek ◽  
Tomáš Frantík
Keyword(s):  
Species Richness ◽  
Czech Republic ◽  
Weather Conditions ◽  
Grass Species ◽  
Individual Species ◽  
Weather Variability ◽  
Grassland Vegetation ◽  
Dry Grassland ◽  
Local Climate ◽  
The Impact

AbstractThe extreme habitats of dry grasslands are suitable for investigations of the response of vegetation to local climate changes. The impact of weather variability on the dynamics of a plant community in a dry grassland was studied. Correlations were found between different functional groups of species and individual species and weather variability. During a 9-year study in five nature reserves in Prague (Czech Republic), the following responses of dry grassland vegetation to weather conditions were observed: (i) wetter conditions, especially in the winter, affected the dominance and species richness of perennial grass species and the decline of rosette plants; (ii) the year-to-year higher temperatures in the winter produced a decline in the dominance of short graminoids and creeping forbs; (iii) spring drought adversely impacted the overall abundance, especially the abundance of dicotyledonous species, and the species richness. However, these relationships may be manifested in different ways in different locations, and in some cases the vegetation of different locations may respond to weather conditions in opposite manners.

Comparison of mayfly (Ephemeroptera) taxocenes of permanent and intermittent Central European small streams via species traits

Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Pavla Řezníčková ◽  
Tomáš Soldán ◽  
Petr Pařil ◽  
Světlana Zahrádková
Keyword(s):  
Global Climate ◽  
Extreme Temperature ◽  
Oxygen Demand ◽  
Hydrological Regime ◽  
Species Traits ◽  
Individual Species ◽  
Biological Traits ◽  
Small Streams ◽  
High Oxygen Demand ◽  
The Impact

AbstractThe recurrent drying out of small streams in past decades has shown an urgent need to pay attention to the impact of global climate change. The objectives of this study were to describe the effect of drying out on the composition of the mayfly taxocene and evaluate the relevance of individual species traits for survival of mayflies to drying out. The mayfly taxocenes of two model localities, one at an intermittent and one at a permanent brook, were investigated in 2002, 2003 and 2005. Compared with the permanent stream, the taxocene of the intermittent stream was short of nine species, foremost rheobionts and high oxygen demand species. To explain further differences between both stream types in survival and recolonisation ability, 15 species traits were evaluated. These included so-called “ecological traits” (e.g., habitat and substrate range, density, distribution, current velocity adaptation) and “biological traits” connected with life cycle and larval/adult adaptations. Species showing the highest number of advantageous traits (with only exception of Electrogena sp. cf. ujhelyii — species of taxonomically unclear status) were able to successfully survive under the unfavourable conditions of the intermittent brook. Biological traits considered more important in many respects seem to be good predictors for assessing sensitivity to extreme temperature changes, hydrological regime fluctuations and the survival/recolonisation ability of species in exposed habitats.

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