Browsing Brage IMR by Author "Pennington, Michael"
Now showing items 1-20 of 25
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A framework for improving accuracy in fisheries data used in stock assessments
Pennington, Michael; Vigneau, Joel; Helle, Kristin; Vølstad, Jon Helge (ICES CM documents;2008/N:27, Working paper, 2009) -
Acoustic and Bottom Trawl Surveys; How Much Information Do They Provide for Assessing the Northeast Arctic Cod Stock?
Korsbrekke, Knut; Mehl, Sigbjørn; Nakken, Odd; Pennington, Michael (ICES CM documents, Working paper, 1999)Acoustic and bottom trawl surveys of the Northeast Arctic cod stock provide fishery independent estimates of trends in abundance and population characteristics. Given the recent uncertainties in the catch based assessment ... -
Adaptive management of living marine resources by integrating different data sources and key ecological processes (ADMAR): A joint effort by IMR and CEES
Handegard, Nils Olav; Stenseth, Nils Christian; Dankel, Dorothy Jane; Durant, Joël M.; Eikeset, Anne Maria; Enberg, Katja; Hjermann, Dag Ø.; Huse, Geir; Pennington, Michael; Skern-Mauritzen, Mette; Stige, Leif Christian; Subbey, Samuel; Vølstad, Jon Helge (ICES CM documents;2010/R:26 Poster;, Working paper, 2010-09) -
An evaluation of survey design for estimating the food consumption by fish
Bogstad, Bjarte; Pennington, Michael; Vølstad, Jon Helge (ICES CM Documents;1991/D:15, Working paper, 1991)The effect of survey design on the precision of estimates of average fish stomach contents is examined. The contribution to the total variance from within and between tow variability in stomach contents is evaluated, ... -
An evaluation of the IMR Summer Bottom Trawl Survey in the Barents Sea
Pennington, Michael (ICES CM Documents;2001/P:16, Working paper, 2001)Summary: A committee was formed to evaluate the Institute of Marine Research summer survey in the Barents Sea, which has been conducted annually since 1995. The primary focus of the committee was the survey’s importance ... -
Assessing the effect of intra-haul correlation and variable density on population estimates from marine surveys
Pennington, Michael; Vølstad, Jon Helge (ICES CM Documents;1991/D:14, Working paper, 1991)In a previous paper (Pennington and Vølstad, Biometrics 47, 1991) it was suggested that reducing the size of the sampling unit generally used in marine surveys could increase the precision of abundance estimates. But if ... -
Assessing the precision of the estimated age distribution of the commercial catch of Northeast Arctic cod
Aanes, Sondre; Pennington, Michael (ICES CM documents, Working paper, 2001)The assessment of Northeast Arctic cod is based on estimates of the commercial catch numbers at age. The age structure of the catch is estimated by sampling individuals from commercial fishing trips. Though it is commonly ... -
Assessing trawl-survey estimates of frequency distributions
Pennington, Michael; Burmeister, Liza-Mare; Hjellvik, Vidar (ICES CM Documents;2000/K:23, Working paper, 2000)Marine trawl surveys catch a cluster of fish at each station and fish caught together tend to have more similar characteristics, such as length, age, stomach contents etc., than those in the entire population. When this ... -
Designing and evaluating length–frequency surveys for trap fisheries with application to the southern rock lobster
Pennington, Michael; McGarvey, Richard (Journal article; Peer reviewed, 2001)A survey design for estimating the length distribution of harvested southern rock lobsters (Jasus edwardsii) was developed for the South Australian fishery. Experimental sampling was carried out by volunteer fishers in ... -
Estimates of effort, CPUE, and mean length for the Norwegian commercial catch of ling, blue ling and tusk
Helle, Kristin; Pennington, Michael (Working paper, 2010) -
Evaluating CPUE series generated by the Norwegian longline fleet for the period 2000-2009
Helle, Kristin; Pennington, Michael; Gundersen, Agnes C. (Conference object, 2010-08) -
An evaluation of recruitment indices for Northeast Arctic cod (Gadus morhua L.)
Helle, Kristin; Bogstad, Bjarte; Marshall, C. Tara; Michalsen, Kathrine; Ottersen, Geir; Pennington, Michael (ICES CM documents, Working paper, 1999)Indices of the abundance of Northeast Arctic cod (Gadus morhua L.) for various life stages were compared in order to determine the earliest stage at .which year-class strength is established. The indices considered are: ... -
Measuring the effect of changes in catchability on the variance of marine survey abundance indices
Pennington, Michael; Godø, Olav Rune (ICES CM Documents;1992/D:9, Working paper, 1992)The average catch per tow by a research vessel survey is often used as an index of abundance. An estimate of the variance of such indices that is based only on the between station variability in catch may underestimate ... -
Measuring uncertainty in trawl surveys: implementation in DATRAS
Larsen, Lena Inger; Öberst, Rainer; Maxwell, David; Pennington, Michael; Sparholt, Henrik; Lassen, Hans (ICES CM documents, Working paper, 2006)Abstract The basic data from several ICES coordinated trawl and beam trawl surveys in the Baltic Sea, the North Sea, the area west of Scotland and France are stored in the DATRAS database in the ICES Secretariat; every ... -
Monitoring ecosystems using research surveys: Maximizing information and minimizing cost
Nakken, Odd; Pennington, Michael (ICES CM documents, Working paper, 2001)Indices or estimates of abundance generated by research vessel surveys are becoming ever more important for assessing marine resources. Most often survey abundance indices are used in conjunction with commercial catch data ... -
Monitoring ecosystems using research surveys; maximizing information and minimizing cost
Nakken, Odd; Pennington, Michael (ICES CM Documents;2002/J:5, Working paper, 2002)Indices or estimates of abundance generated by research vessel surveys are becoming ever more important for assessing marine resources. Most often survey abundance indices are used in conjunction with commercial catch data ... -
On the relation between ‘true’ numbers of Northeast Arctic cod and VPA- or survey-based abundance estimates
Nakken, Odd; Pennington, Michael (ICES CM documents, Working paper, 2001)When assessing Northeast Arctic cod it is assumed that the estimates of numbers at age generated by a converged VPA type analysis are equal, on average, to the true numbers at age. Based on fishery independent survey ... -
Optimum size of sampling unit for estimating the density of marine populations
Pennington, Michael; Vølstad, Jon Helge (ICES CM Documents;1989/D:22, Working paper, 1989)Data from several trawling experiments and from some scallop dredge surveys indicate that, within limits, a srnaller sampling unit can be more effective than a larger unit for marine abundance surveys. Taking into account ... -
Probability-based surveying using self-sampling to estimate catch and effort in Norway’s coastal tourist fishery
Vølstad, Jon Helge; Korsbrekke, Knut; Nilsen, Merete; Nilsson, Gro N.; Pennington, Michael; Subbey, Samuel; Wienerroither, Rupert (Journal article; Peer reviewed, 2011-06-08)Recreational fishing as a tourist activity has become an increasingly important part of the Norwegian travel industry and may contribute significantly to the fishing mortality on Norwegian coastal cod (Gadus morhua). ... -
Report of the workshop on comparison of stock assessment model strategies, with application to northeast artic cod, 1-4 December 1998
Pennington, Michael (Fisken og havet, Research report, 1999)