FN Archimer Export Format PT J TI Detecting sampling outliers and sampling heterogeneity when catch-at-length is estimated using the ratio estimator BT AF VIGNEAU, Joel MAHEVAS, Stephanie AS 1:1;2:2; FF 1:PDG-DOP-DCMMN-HMMN-RHPEB;2:PDG-DOP-DCN-EMH; C1 IFREMER, F-14520 Port en Bessin, France. IFREMER, F-44311 Nantes, France. C2 IFREMER, FRANCE IFREMER, FRANCE SI PORT-EN-BESSIN NANTES SE PDG-DOP-DCMMN-HMMN-RHPEB PDG-DOP-DCN-EMH IN WOS Ifremer jusqu'en 2018 IF 1.934 TC 1 UR https://archimer.ifremer.fr/doc/2007/publication-2731.pdf LA English DT Article DE ;Stratification;Sampling design;Market sampling;Length structure AB Measuring fish on board fishing vessels or at fish markets to collect data for stock assessment purposes is one of the most straightforward actions carried out by fisheries scientists worldwide. However, such samples are not straightforward to handle and analyse because of their vector-type structure. A generic tool that allows investigation in any multinomial-like sampling scheme is provided, as long as the scheme is built on a ratio estimator, which is the case for most length sampling in the fisheries sector. The use of this tool is discussed using data obtained from two different sampling designs, one consisting of commercial market samples by category and the other on fishing activity or metier. The identification of outliers, misallocated samples, or potential bias as well as the analysis of heterogeneity within and between strata are discussed. The objective of such exploratory analyses is to help sampling coordinators design the best sampling scheme and improve the quality of input data for stock assessment models. The statistics described here are easy to implement and their use is recommended as a necessary stage before any use of sampling data at an international level. PY 2007 PD JUN SO ICES Journal of Marine Science SN 1054-3139 PU Oxford university press VL 64 IS 5 UT 000247991500019 BP 1028 EP 1032 DI 10.1093/icesjms/fsm077 ID 2731 ER EF