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

2. Instituto Fomento Pesquero - Chile
Spatial strata
Instituto Fomento Pesquero - Chile

3. 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

4. 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

5. 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.

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

7. 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.

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

9. Some examples: Jack mackerel sampled in Chile 1998-2006