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Geo-referenced size-frequency data - Swordfish (SWO)

Reference: 
IOTC-2026-WPB24-DATA06
File: 
Package icon IOTC-2026-WPB24-DATA06_SF_SWO.zip
Type: 
Datasets
Year: 
2026
Meeting: 
Working Party on Billfish (WPB)
Meeting session: 
24
Availability: 
13 July 2026
Authors: 
IOTC Secretariat
Abstract: 

Metadata for Geo-referenced Size-Frequency Data for Swordfish

Author: IOTC Secretariat

 

This dataset corresponds to the size-frequency (SF) data for Swordfish (Xiphias gladius), classified by fishing fleet, year, gear, type of school, time interval (usually monthly), spatial stratum (typically CWP square grids of 5°×5°), and fork length class. The size data may originate from samples or have been raised to represent the total catch.

Size measurements have been consolidated following the processing steps described in IOTC-2020-WPDCS16-16. The conversion factors and morphometric relationships used to convert all size measurements to fork lengths are available in Table 1.

Table 1: IOTC reference length-weight power relationships for Indian Ocean narrow-barred Spanish mackerel. FL = fork length (cm); TL = total length (cm); RD = round weight (kg)

Code

Species

Source Length type

a

b

Allometric relationship

Min length

Max length

Reference

SWO

Swordfish

EFL

1.0600e+00

9.02700

LJFL = a*EFL+b

50

254

Setyadji et al. (2016)

SWO

Swordfish

PFL

1.2410e+00

12.44000

LJFL = a*PFL+b

51

254

Setyadji et al. (2016)

SWO

Swordfish

PFL

1.1680e+00

3.53200

EFL = a*PFL+b

52

254

Setyadji et al. (2016)

SWO

Swordfish

PFL

3.0000e-05

2.94000

GUT = a*PFL^b

80

180

Setyadji et al. (2016)

SWO

Swordfish

LJFL

8.5703e-08

3.91763

GUT = a*LJFL^b

80

155

Garcia-Cortés and Mejuto 2002

SWO

Swordfish

EFL

1.0660e+00

10.44900

LJFL = a*EFL+b

48

255

Poisson and Taquet (2001)

SWO

Swordfish

CKL

1.5411e+00

19.60500

LJFL = a*CKL+b

32

180

Poisson and Taquet (2001)*

SWO

Swordfish

PAL

2.5407e+00

25.69800

LJFL = a*PAL+b

18

105

Poisson and Taquet (2001)*

SWO

Swordfish

LJFL

5.8641e-06

3.08490

GUT = a*LJFL^b

90

250

Poisson and Taquet (2001)*

SWO

Swordfish

LJFL

3.8150e-06

3.18800

RD = a*LJFL^b

89

266

Mejuto et al. (1998)*

The data originate from the IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs) as per the IOTC data requirements (Resolution 15/02). They are submitted annually, mostly using IOTC Form SF, and curated by the Secretariat for dissemination prior to IOTC Working Parties and other scientific data users.

 

Global attributes

  • Title: Size-frequency data of narrow-barred Spanish mackerel by fleet, 1970-2024
  • Summary: Curated dataset providing detailed information on the size composition of the catch of Swordfish (Xiphias gladius) in the Indian Ocean
  • Context of development: Management of tuna and tuna-like species under IOTC mandate
  • Data origin: Size-frequency data collected on land or at sea by national institutions and the fishing industry, with some data having been previously extrapolated to represent the broader fishery
  • Lineage: Data submitted by CPCs and consolidated
  • Keywords: size composition, morphometrics, tuna fisheries
  • Type: Tabular file
  • Format: CSV
  • Size:
    • 142,506 KB for original dataset
    • 3,284 KB for compressed dataset
  • Structures: rows x columns for catch dataset
  • Geographic description: Fishing areas within the Indian Ocean
  • Update frequency: According to data revisions and updates
  • Metadata production date: 13 July 2026
  • Source: IOTC
  • Data curator: IOTC Secretariat
  • Contact: IOTC-Statistics@fao.org
  • Associated rights: Public-domain data requiring source acknowledgement
 

Data fields

FIELDDEFINITIONCODE LIST
YEARGregorian calendar year of the fishing activities reported through the dataset 
MONTH_STARTStart month of the fishing activities reported through the dataset 
MONTH_ENDLast month of the fishing activities reported through the dataset 
FISHING_GROUND_CODEIOTC code for fishing areasFishing Grounds
FLEETIOTC legacy code and label for fishing fleetsFleets
FISHERY_TYPEIOTC legacy code and label for the main types of fisheriesTypes of Fisheries
FISHERY_GROUPIOTC legacy code and label for the broader grouping of fisheriesGroups of Fisheries
FISHERYIOTC legacy code and label for the fishery in which the catch was takenFisheries
GEARIOTC legacy code and label for fishing gearsGear
SCHOOL_TYPE_CODEIOTC legacy code for types of fish school associationSchool Types
SPECIES_CATEGORYCategory of the species or taxon within the IOTC classification (e.g., seerfish)Categories of Species
SPECIESASFIS three-alpha code for speciesSpecies
RAISINGIndicates whether the size data are original or raised samplesRaisings
CLASS_LOWLower bound value of the size class interval (cm) 
CLASS_HIGHUpper bound value of the size class interval (cm) 
FISH_COUNTNumber of fish estimated in each size class interval 
 

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