Where does my data go? Preparation of files for the assessments of IOTC stocks and use of data for...

Where does my data go?Preparation of files for the assessments of IOTC stocks and use of data for the assessments of

IOTC species

Mauritius, 18-20 March 2014Compliance Workshop: Collection and reporting of Fisheries data to IOTC

Sponsored by BOBLME-IOC-SmartFish-IOTC

Building blocks of Tuna stock assessments

• Catch-and-effort data• Landed (Nominal) catch (sale slips; sampling)• Discard levels (observers; logbooks)• Effort (logbooks; sampling)• Size/age composition (sampling; tagging)

• Abundance trends• Fishery CPUE (fine-scale operational data from

logbooks)• [Size/age/sex composition (logbooks; sampling;

tagging)]

• Exploitation rates (tagging)

• Life history information• Longevity/natural mortality (tagging; otoliths)• Growth (tagging; otoliths)• Maturation (biological samples)

Spatial and seasonal patterns

Routine Data

Collection

Data Collection

through specific projects

(updated regularly)

Building blocks of management advice

Slide from R. Method modified by Joseph E.

Powers

Input files prepared for the assessments

IOTC SECRETARIAT

• Catch [and effort] data by species, time-period (usually quarter), fishery (groups of Flag-Gear combinations depending on the selectivity) and areas (depending on the dynamics of the fleets and species for assessment)

• Number of fish sampled by species, size bin, time-period… (as above)

• Length-weight, growth, and other functions used for each species

• Life history information

FLAG STATES

• Indices of abundance (from as many fleets as possible); estimated using fine-scale operational data (logbooks)

Example of BET input files

Bigeye tuna SS3 Assessment

Species Species code (BET: bigeye tuna)

Fishery Type of fishery: the following fisheries were identified:PSFS Industrial purse seines on free-swimming schoolsPSLS Industrial purse seines on associated schools (FAD)

LL [Deep-]freezing longline fisheries, especially Japan, Korea, Taiwan,China, Seychelles, and EUFL Fresh-tuna longline fisheries, especially Indonesia and Taiwan,ChinaBB All pole-and-line and small seine fisheries (catching small fish)

LINE All fisheries using handlines, and small longlines, including the gillnet and longline combination fishery of Sri LankaOTHER Other fisheries including gillnet, trolling and other minor artisanal gears

Year The year where the catches were made

Quarter The quarter where the catches were made (Jan-Mar(1), Apr-Jun(2), Jul-Sep(3), Oct-Dec(4))

no Total catch estimated (in numbers of fish)mt Total catch estimated (in metric tonnes)noSamp

L010…L308 Number of bigeye tuna sampled by (fork) length class, using 10cm as the first class(lower bound) and 2cm intervalsL010 Number of BET specimens having a fork length between 10cm (inclusive) and 12cm (exclusive)L012 Number of BET specimens having a fork length between 12cm (inclusive) and 14cm (exclusive)And so forth

The catches for fisheries for which catches by quarter were not available were allocated using the proportion that the catches in each quarter made in other years for the same fleet, for other fleets in the same or other years or were assigned proportionally by quarter, depending on the case

Total number of fish sampled: Note that the numbers of fish refer to actual numbers of fish sampled in all fisheries but the PSLS and PSFS fisheries, where they refer to the number of specimens raised to the sampling unit (i.e. number of fish estimated for the sets withing the fish compartment (fish well) sampled)

Steps in the preparation of datasets

10

SF aggregated per Species, Fleet, Gear Type, Grid and time interval

12

SF data assigned per Species-Fleet-Gear-School Type-Year-Quarter-SF Grid ( EC PS Areas for PS, 10*20 degrees Areas for all

other gears)

11

Flow-chart: Estimation of Catch-at-Size Tables and Spatial Catches

Yellowfin tuna (YFT), Bigeye Tuna (BET), Skipjack Tuna (SKJ), Albacore (ALB) and Swordfish (SWO)

SF data assigned to standard length (fork length) and size interval (1, 2 or 3 cm

depending on the species)

Nominal catches of species groups assigned per species (amounts estimated

added to the strata concerned)

Size Frequency data Table (SF)

CE strata recorded under irregular areas assigned to regular grids

5

2

Nominal catches Table (NC)

CE data raised to total catch according to total NC recorded and average weight per

stratum estimated from SF

3

4

SF

1

CE data dissaggregated per Species-Fleet-Gear-School Type-Year-Month-Standard

Grid (5 degrees square)

13

14

CE aggregated per Species-Fleet-Gear-School Type-Year-Quarter-SF Grid

6

7

CE estimated for NC strata for which no CE data are available (amounts estimated


CE aggregated per Species, Fleet, Gear Type, Grid and time interval

8

9

SF estimated for CE strata for which no SF data are available

SF strata recorded under irregular areas assigned to regular grids

Nominal catches aggregated per Species, Fleet, Gear Type, IOTC Area and Year

IOTC Database

Catch and effort Table (CE)

NC CE

CE data assigned per Species-Fleet-Gear-School Type-Year-Month-Standard Grid (5

degrees square)

NOMINAL CATCH





10


12


other gears)

11









5

2




3

4

SF

1



13

14


6

7




8

9




IOTC Database


NC CE


degrees square)





degrees square)








CATCH-AND-EFFORT

Steps in the preparation of datasets (cont.)

10


12


other gears)

11









5

2




3

4

SF

1



13

14


6

7




8

9




IOTC Database


NC CE


degrees square)

INDIVIDUAL LENGTH DATA







other gears)


-100

-75

-50

-25

0

25

50

75

100

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

8

6

4

2

0

Nominal Catch: What is missing ?

-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRIBLTCO

MG

UT

ALL

8

6

4

2

0

-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRICO

MG

UT

ALL

8

6

4

2

0

• The majority of countries attending the Workshop have not reported nominal catches as per the standards agreed by the IOTC

• On the contrary, other countries have adhered in general to the standards, for most IOTC species

• The IOTC Secretariat has to estimate catches when reports are incomplete 75% of the catches over the history of the fishery

Attending the Workshop

Attending the WorkshopAll IOTC Species

Not attending the Workshop

By Species

-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRICO

MG

UT

ALL

8

6

4

2

0

-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRIBLTCO

MG

UT

ALL

8

6

4

2

0

Catch-and-Effort: What is missing ?• The majority of countries attending the

Workshop have not reported catch-and-effort data at all (red)

• Where reported, catch and effort is not by the standards in most cases (light green)

• On the contrary, levels of reporting for other countries are higher with data reported by the standards in most cases

• Levels of reporting have only slightly improved over time and remain very low

Attending the Workshop Not attending the Workshop

By Species

-100

-75

-50

-25

0

25

50

75

100

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

8

6

4

2

0


-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRICO

MG

UT

ALL

8

6

4

2

0

-100

-75

-50

-25

0

25

50

75

100

YFTBETALBSBFSKJSW

OBLMBU

MM

LSSFALO

TKAWFRIBLTCO

MG

UT

ALL

8

6

4

2

0

Size Frequency: What is missing ?• The majority of countries attending the

Workshop have not reported size frequency data at all (red)

• Where reported, size frequency is not by the standards in most cases (light green; orange)

• On the contrary, levels of reporting for other countries are higher with data reported by the standards in most cases

• Levels of reporting have only slightly improved over time and remain very low

Attending the Workshop Not attending the Workshop

By Species

-100

-75

-50

-25

0

25

50

75

100

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

8

6

4

2

0


Conclusion

The quality of the management advice depends on the quality of the data that

feeds the assessment and the uncertainty associated to the results;

If data completeness and quality does not improve we have to live with what we have and take more conservative actions to ensure that IOTC stocks are

safe

THANK YOU FOR

YOUR ATTENTION

Mauritius, 18-20 March 2014Compliance Workshop: Collection and reporting of Fisheries data to IOTC

Sponsored by BOBLME-IOC-SmartFish-IOTC

www.iotc.org

http://www.iotc.org/

http://www.iotc.org/

Where does my data go? Preparation of files for the assessments of IOTC stocks and use of data for...

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