Brief description of the jack mackerel sampling in the Chilean South-Central fishery Data&Information Working Group, 5th International Meeting. Guayaquil, Ecuador. March, 2008

Instituto Fomento Pesquero - Chile Spatial strata Instituto Fomento Pesquero - Chile

Instituto Fomento Pesquero - Chile Sampling program The sampling standard is based under ISO-9001 norms. The sampling is based in a statistical sampling design. This is based on numbers of trips by month and zone. A similar sampling is done from 32ºS toward the north. Sampling for species proportion, size and biological aspects 100,000 fish by year (national level) are sampled for length composition, and about a 10% is sub-sampled for biological aspects Instituto Fomento Pesquero - Chile

Sampling for species proportions and length composition The sample of fish is taken during the landing using a plastic box of 44 lt. (random) Instituto Fomento Pesquero - Chile

Species proportions and length sampling process The size is measured at the fork length with a precision of 1 cm (Figure 1); the class mark is recorded.

Biological sampling process A sub-sample is taken for biological aspects like length, weight, sex, maturity and otoliths.. Instituto Fomento Pesquero - Chile

Biological sampling process Otolith by size class. 24 pair by length-class and month are collected: 12 pairs in the first week of each month, and 6 pairs by week the next two weeks The fish weight is measured with a precision of 0,1 gr in lab and 1 gr on board The weighing equipment are periodically calibrated to avoid bias.

Recording the data The data is recorded in electronic media and delivered through email, pocket-PC’s and satellites cellphone

Some examples: Jack mackerel sampled in Chile 1998-2006