Modeling the consequences of Antarctic krill harvesting on Antarctic fur seals

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first_imgIn terms of the convention governing the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), management advice for the Antarctic krill (Euphausia superba) fishery should take the needs of the predators of krill into account in order to reduce the risk of deleterious impacts on such predators (e.g., baleen whales and numerous fish, seal, penguin, and flying bird species). A single species yield model is currently being used by the CCAMLR Scientific Committee to recommend an annual krill catch limit, which is expressed as a proportion (γ = 0.116) of a survey biomass estimate. This approach takes the needs of predators into account in only a crude way by assuming that a median krill escapement of 75% of its unexploited biomass would be sufficient to meet the needs of predators. A krill–predator modeling procedure is presented that could be used to directly assess the impact of krill harvesting on krill predator populations and therefore to revise this recommended harvesting level (γ) for Antarctic krill. Application of a deterministic form of this model to an Antarctic fur seal (Arctocephalus gazella) data set from Bird Island, South Georgia, Antarctica, indicates that the level of krill fishing intensity (γ) that would reduce this population to half the equilibrium size in the absence of krill fishing (γhalf) lies between 0.03 and 0.18, which includes the level recommended by CCAMLR. This large range results primarily from the sensitivity of the model to the maximum growth rate parameter, for which a range of 5–15%/yr is investigated. A plausible range of values for this parameter (5–15%/yr) results in estimated γhalf values from 0.04 to 0.23. Stochastic calculations (which take account of interannual fluctuations in the abundance of the krill population due to recruitment variability) yield higher estimated γhalf values than the less realistic deterministic calculations. However, simulation tests indicate that the estimated γhalf values are biased upward; this modeling approach is therefore likely to yield γhalf values that would lead to a depletion of the Antarctic fur seal population to more than half its pristine size.last_img

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Design your own Comic Relief Red Nose

first_img Howard Lake | 2 October 2017 | News WATCH: The history of the red nosesHow well do you remember all the many red nose designs for Red Nose Day?[youtube]https://www.youtube.com/watch?v=gg2CsLtCwNg[/youtube]  422 total views,  2 views today AddThis Sharing ButtonsShare to TwitterTwitterShare to FacebookFacebookShare to LinkedInLinkedInShare to EmailEmailShare to WhatsAppWhatsAppShare to MessengerMessengerShare to MoreAddThis8 AddThis Sharing ButtonsShare to TwitterTwitterShare to FacebookFacebookShare to LinkedInLinkedInShare to EmailEmailShare to WhatsAppWhatsAppShare to MessengerMessengerShare to MoreAddThis8 For the first time Comic Relief is inviting ideas for new designs for their fundraising icon, the Red Nose. School children across the UK are being encouraged to design next year’s Red Nose for Comic Relief’s 2019 Red Nose Day in March.One pupil’s design will be selected as the winner and go on sale in Sainsbury’s and Oxfam shops across the country. Five runners-up will also have their nose designs 3D printed.Magical landThe theme for the character to be designed is ‘magical land’. Designs have to be submitted on the official template and they have to be original, and to appeal to a wide audience “but especially children and young people”.The nose designs must use only red, white, silver or gold as the main Nose colour, although black and white can be used for detail.The closing date for entries to The Red Nose Design Challenge is 8 December 2017 at 5pm. There is a maximum number of seven entries per school. About Howard Lake Howard Lake is a digital fundraising entrepreneur. Publisher of UK Fundraising, the world’s first web resource for professional fundraisers, since 1994. Trainer and consultant in digital fundraising. Founder of Fundraising Camp and co-founder of GoodJobs.org.uk. Researching massive growth in giving.center_img Design your own Comic Relief Red Nose Tagged with: Comic Relief Red Nose Day Advertisement  421 total views,  1 views todaylast_img

Entries open for 2020 Insight in Fundraising Awards

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Airport shutdowns confirm: People Power will bring Trump down!

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