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Please use this identifier to cite or link to this item: http://hdl.handle.net/10793/832

Title: Porcupine Bank Nephrops Grounds (FU16) 2012 UWTV Survey Report and catch options for 2013
Authors: Lordan, Colm
Doyle, Jennifer
Dobby, Helen
Hehir, Imelda
Fee, Dermot
Allsop, Chris
O'Neill, Ross
Keywords: Nephrops norvegicus
Porcupine Bank
stock assessment
geostatistics
underwater television (UWTV)
benthos
Issue Date: 2012
Publisher: Marine Institute
Citation: Lordan, C., Doyle, J., Dobby, H., Heir, I. Fee, D., Allsop, C. & O’Neil, R. 2012. Porcupine Bank Nephrops Grounds (FU16) 2012 UWTV Survey Report and catch options for 2013. Marine Institute UWTV Survey report.
Abstract: This report provides the results of the first underwater television on the ‘Porcupine Bank Nephrops grounds’ ICES assessment area; Functional Unit 16. The survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. The UWTV results and a scientific basis for survey based catch advice in 2013 are presented. In total 47 UWTV stations were successfully completed. The mean burrow density was 0.19 burrows/m² (empirical 95% confidence intervals are from 0.17-0.21). The final krigged abundance estimate was 992 million burrows with a relative standard error of 5% and an estimated stock area of 7,100km2. This abundance estimate can be considered as a conservative estimate given that the spatial coverage of the southern part of the ground was not complete. A correction factor of 1.26 is proposed based on expert judgments of burrow size and potential detection and identification biases. A yield and spawner per recruit analysis was used to estimate a harvest rate of 5.0% for the combined sex F0.1 and other F reference points. This harvest rate is low compared to other FUs and can be considered very conservative. Applying this harvest rate to the abundance observed in the survey and using a mean weight in the landings of 45.0g implies landings in 2013 of 1,770 t. The results here could form the basis of the catch advice for 2013.
Description: Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report.
URI: http://hdl.handle.net/10793/832
http://catalog.marine.ie/geonetwork/srv/en/main.home
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