General purpose

Effective collection and reporting of fisheries data are essential for conserving and sustainably managing tuna and tuna-like species in the Indian Ocean. The Indian Ocean Tuna Commission (IOTC) has identified several datasets critical for monitoring tuna and tuna-like fisheries and analysing the status and trends of both the populations and the marine ecosystems that support them. These datasets must be reported by the IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs) as part of the IOTC Agreement but they are also requested from any other parties that fish in the IOTC area of competence for species managed by the IOTC.

Since its establishment in 1996, the IOTC has developed and implemented several Conservation and Management Measures (CMMs) which include specific provisions on the nature and characteristics of the data that must be collected and reported to the IOTC Secretariat. It is the responsibility of each country to establish and enforce data recording and reporting systems that meet the criteria set by the IOTC through its CMMs and the Secretariat oversees the collation and curation of the different datasets that support the IOTC scientific process.

The overarching objective of the Data Reporting Guidelines (DRGs) is to provide a set of rules and best practices to the staff responsible for the collection and reporting of fisheries and biological data to the IOTC Secretariat according to the CMMs in place. The DRGs aim to:

  1. Introduce the users to the IOTC terminology (section Terminology)
  2. Provide the framework and standards for reporting the elements of the data along with the metadata information required for their storage and management (section Metadata)
  3. Describe the contents of each dataset as included in the mandatory IOTC reporting forms (section Datasets),
  4. Present the IOTC data quality control procedure and detail the checks to be performed on the metadata and data prior to any submission (section Quality control procedure)
  5. Explain the main features of the submission process, including details on the data submission platform, reporting timeline, structure of the files to be reported, and procedure for revising historical submissions (section Submission procedure).

These guidelines do not include the reporting requirements related to the Regional Observer Scheme (ROS; 22/04) as well as to the monitoring of authorised and active fishing vessels (Res. 10/08 and Res. 19/04), landings and transshipments of fish products in fishing ports (Res. 16/11), and transshipments at sea (Res. 23/05) which are managed by the compliance section of the Secretariat.

Terminology

While many definitions, classifications, and standards within the IOTC are consistent with those of the Coordinating Working Party on Fishery Statistics (CWP), the Commission also employs several technical terms and definitions unique to its operations, which are crucial for accurately reporting fisheries data to the Secretariat.

Area of competence

The IOTC area of competence is defined in the article II of the IOTC Agreement and corresponds to “the Indian Ocean and adjacent seas, north of the Antarctic Convergence, insofar as it is necessary to cover such seas for the purpose of conserving and managing stocks that migrate into or out of the Indian Ocean”. For statistical purposes, the IOTC area of competence is split between two main areas: the Western Indian Ocean and Eastern Indian Ocean (Fig. 1).

Main areas of the IOTC area of competence

Figure 1: Main areas of the IOTC area of competence

Species of interest

The 16 species and stocks managed by the IOTC – hereinafter referred as the IOTC species and IOTC stocks – are defined in the article III of the IOTC Agreement. It is important to note that the distribution of the stock of southern bluefin tuna (Thunnus maccoyii) extends over the Atlantic, Indian, and Pacific Oceans, and its actual management is under the responsibility of the Commission for the Conservation of Southern Bluefin Tuna (CCSBT).

In addition, the IOTC identified a list of species, mostly composed of commonly caught elasmobranch species, for which data reporting obligations apply as for the IOTC species. The Annex 2 of Res. 15/01 provides this list of species and species groups by gear group and was further complemented for all manta rays through Res. 19/03.

Res. 15/01 further includes groups of Endangered, Threatened, and Protected (ETP) species that may interact with IOTC fisheries and for which data collection and reporting has been defined through specific CMMs: marine turtles (Res. 12/04), whale sharks (Rhincodon typus) (Res. 13/05), cetaceans (Res. 23/06), and seabirds (Res. 23/07).

Finally, and while optional, the reporting of statistics for all other bycatch species is encouraged to monitor the ecosystem effects of fishing, especially when the catches of these species represent a significant proportion of the total catches of the fishery concerned.

Fishing fleet

A fishing fleet is a group of fishing vessels that may operate in the IOTC area of competence and whose fishing operations and catches of tuna and tuna-like species are under the responsibility of a political entity or sub-entity recognized by the IOTC. The fishing fleet is derived from the combination of the flag state and reporting entity (see section on Reporting metadata). In most cases, the fishing fleet corresponds to the flag state but some differences stem from: (i) when the CPC is composed of multiple entities (i.e., European Union (EUR) and China (CHN)), (ii) the cases of France Overseas Territories (FRAT) and British Indian Overseas Territories (GBRT), and (iii) the existence of estimates of unreported catches not included elsewhere (e.g., NEI.PS) that need to be accounted for in the IOTC process.

Fishery categories

The three main IOTC fishery categories are defined according to the main gear used by the vessel and their recording in the IOTC Record of Authorised Vessels (RAV): (i) longline fisheries, (ii) surface fisheries, and (iii) coastal fisheries, also called artisanal fisheries (see footnote 1 of IOTC Res. 15/02). The IOTC data reporting obligations defined through the CMMs vary according to the fishery categories.

Fisheries

The IOTC fisheries are derived from the combination of several factors: (i) the fishery purpose, (ii) the area of operation, (iii) the vessel size range, (iv) the gear group, (v) the gear, (vi) the gear configuration, (vii) the fishing mode in the case of purse seines, hooks and lines, and pole-and-lines, and (viii) the target species. The IOTC fishery identification wizard has been designed to guide the adoption of the new fishery classification by providing an interactive tool which generates the code and definition of the fishery based on the aforementioned factors.

Metadata

Reporting submission

Some mandatory (M) and optional (O) descriptive metadata elements have been identified to provide key information related to the submission and management of the data.

Element Requirement Description Format Example
Focal point full name M Name of the focal point in charge of the reporting of the data to the IOTC Secretariat Plain text John Doe
Focal point email M Email address of the focal point in charge of the reporting of the data to the IOTC Secretariat Valid email address
Organisation name M Name of the organisation in charge of the reporting of the data to the IOTC Secretariat Plain text National Institute of Fisheries
Organisation email O Email address of the organisation in charge of the reporting of the data to the IOTC Secretariat Valid email address
Finalisation date M Date of finalisation of the dataset ISO 8601 1996-03-27
Submission date M Date of submission of the dataset ISO 8601 1997-03-21

Data characteristics

Some general information is required to describe the main characteristics of the data reported to the Secretariat, including the reporting entity and flag state that define the fishing fleet and are common to all datasets, and some additional descriptors providing details on the origin and processing procedure applied to the data reported for each stratum, i.e., unique combination of elements defining the datasets.

All datasets

Element Requirement Description Codelist
Reporting year M Gregorian calendar year of the fishing activities reported through the dataset Integer
Reporting entity M Code of the entity reporting the dataset to the IOTC Secretariat Entity
Flag state M Code of the country registration of the fishery vessels Countries

Interactions with Endangered, Threatened and Protected species dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Source coverage type O Variable used for data coverage Coverage types

Amount of fish caught and retained dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Original data source M Source of information Sources
Original data processing M Processing applied to the data Processings
Source coverage type M Variable used for data coverage Coverage types

Amount of discards dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Original data source M Source of information Sources
Original data processing M Processing applied to the data Processings
Source coverage type M Variable used for data coverage Coverage types
Data raising M Level of raising (i.e., extrapolation) Raisings

Geo-referenced catches and efforts dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Original data source M Source of information Sources
Original data processing M Processing applied to the data Processings
Source coverage type M Variable used for data coverage Coverage types
Data raising M Level of raising (i.e., extrapolation) Raisings

Geo-referenced size frequencies dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Original data source M Source of information Sources
Original data processing M Processing applied to the data Processings
Estimation M Origin of the data (i.e., observed or estimated) Estimations
Source coverage type M Variable used for data coverage Coverage types
Data raising M Level of raising (i.e., extrapolation) Raisings

Fishing craft statistics dataset

Element Requirement Description Codelist
Original data type M Preliminary/final status of the data Type of data
Original data source M Source of information Sources
Original data processing M Processing applied to the data Processings
Source coverage type M Variable used for data coverage Coverage types

Datasets

Species presence in the catch

Description

Matrix of presence of species in the retained catches and discards of each fishing fleet by gear group and broad fishery category.

Conservation and Management Measures

  • Res. 15/01 (Annex II) – On the recording of catch and effort data by fishing vessels in the IOTC area of competence
  • Res. 18/07 (para. 4) – On measures applicable in case of non-fulfilment of reporting obligations in the IOTC

Contents

Matrix table with species in rows and gear groups in columns. For each species/gear combination, the cell must be filled with either a value of one (1) in case of positive catch or a value of zero (0) in case of absence of catch (i.e., no landing and no discard). Species include IOTC species, mobulid rays, common sharks, and other bycatch species. All gear groups (hooks and lines, pole-and-lines, longlines, purse seines, gillnets, and other gears) are included and further broken down by broad fishery category, i.e., coastal and industrial.

Reporting form details

Form 1DR

Interactions with Endangered, Threatened and Protected species

Description

Annual estimates of the numbers of interactions of longline fisheries and surface fisheries with endangered, threatened, and protected species by fishing fleet, fishery, IOTC main area, and species group.

Conservation and Management Measures

  • Res. 12/04 (para. 3) – On the conservation of marine turtles
  • Res. 13/05 (para. 7) – On the conservation of whale sharks (Rhincodon typus)
  • Res. 23/06 (para. 9) – On the conservation of cetaceans
  • Res. 23/07 (para. 1) – On reducing the incidental bycatch of seabirds in longline fisheries

Contents

Number of interactions with marine turtles, seabirds, mobulid rays, cetaceans and whale sharks, with information on national legislation in place in the case of cetaceans and whale sharks. For each stratum, the data coverage – i.e., the percentage (%) of occurrences of interactions sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates.

Data dimensions

Main elements
Original data
Source coverage

Reporting form details

Form 1IN

Amount of fish caught and retained

Description

Total annual estimates of the amount of fish caught and retained by fishing fleet, fishery, IOTC main area, retain reason, and species.

Conservation and Management Measures

  • Res. 15/01 (Annex II) – On the recording of catch and effort data by fishing vessels in the IOTC area of competence
  • Res. 15/02 (para. 2) – On mandatory statistical reporting requirements for IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs)
  • Res. 17/05 (para. 6) – On the conservation of sharks caught in association with fisheries managed by IOTC
  • Res. 18/02 (para. 3) – On management measures for the conservation of blue shark caught in association with IOTC fisheries
  • Res. 18/05 (para. 8) – On management measures for the conservation of the billfishes: striped marlin, black marlin, blue marlin and Indo-Pacific sailfish
Retention bans in longline and surface fisheries
  • Res. 12/09 – On the conservation of thresher sharks (family Alopiidae) caught in association with fisheries in the IOTC agreement area
  • Res. 13/06 – On a scientific and management framework on the conservation of sharks in association with IOTC managed fisheries – Oceanic whitetip shark
  • Res. 19/03 – On the conservation of mobulid species caught in association with fisheries in the IOTC area of competence

Contents

Estimates of retained catches in live weight equivalent (metric tonnes; t) for the IOTC species, common sharks, and other bycatch species. Reporting of quarterly estimates is voluntary and recommended to assess seasonality of the retained catches. For each stratum, the data coverage – i.e., the percentage (%) of amount of fish sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates.

Reporting form details

Form 1RC

Amount of discards

Description

Total annual estimates of the amount of fish caught and discarded by fishing fleet, fishery, IOTC main area, species, and condition.

Conservation and Management Measures

  • Res. 15/01 (Annex II) – On the recording of catch and effort data by fishing vessels in the IOTC area of competence
  • Res. 15/02 (paras. 2-3) – On mandatory statistical reporting requirements for IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs)
  • Res. 12/09 (paras. 3-5, 8) – On the conservation of thresher sharks (family Alopiidae) caught in association with fisheries in the IOTC agreement area
  • Res. 13/06 (paras. 4-5, 8) – On a scientific and management framework on the conservation of sharks in association with IOTC managed fisheries
  • Res. 17/05 (para. 6) – On the conservation of sharks caught in association with fisheries managed by IOTC
  • Res. 18/02 (para. 3) – On management measures for the conservation of blue shark caught in association with IOTC fisheries
  • Res. 19/03 (para. 8) – On the conservation of mobulid species caught in association with fisheries in the IOTC area of competence

Contents

Estimates of discards in numbers or live weight equivalent for the IOTC species, mobulid rays, whale sharks, cetaceans, common sharks, and other bycatch species. Reporting of quarterly estimates is voluntary and recommended to assess the seasonality of the discards. For each stratum, the data coverage – i.e., the percentage (%) of amount of fish sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates.

Reporting form details

Form 1DI

Geo-referenced catches and efforts

Description

Estimates of species-specific catches and efforts by fishing fleet, fishery, and space and time strata.

Conservation and Management Measures

  • Res. 15/01 (Annexes I-III) – On the recording of catch and effort data by fishing vessels in the IOTC area of competence
  • Res. 15/02 (para. 4) – On mandatory statistical reporting requirements for IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs)
  • Res. 17/05 (para. 6) – On the conservation of sharks caught in association with fisheries managed by IOTC
  • Res. 18/02 (paras 2-3) – On management measures for the conservation of blue shark caught in association with IOTC fisheries
  • Res. 18/05 (para. 8) – On management measures for the conservation of the billfishes: striped marlin, black marlin, blue marlin and Indo-Pacific sailfish
Retention bans in longline and surface fisheries
  • Res. 12/09 – On the conservation of thresher sharks (family Alopiidae) caught in association with fisheries in the IOTC agreement area
  • Res. 13/06 – On a scientific and management framework on the conservation of sharks in association with IOTC managed fisheries – Oceanic whitetip shark
  • Res. 19/03 – On the conservation of mobulid species caught in association with fisheries in the IOTC area of competence

Contents

  • Estimates of efforts expressed in units consistent with the recording requirements established in Res. 15/01 and complemented by numbers of fishing operations for longline fisheries and surface fisheries (IOTC-2022-SC25-R). The use of trips as effort unit is not recommended as trip length may vary substantially according to vessel length, fishing success, and multiple technical factors (e.g., fuel exhaustion). In the case of purse seine fisheries, other units could be added to refine the information on effort such as searching time and surface area explored.
Gear group Primary effort Secondary effort Tertiary effort
Gillnets (GI) Number of fishing days Number of nets deployed Total net surface deployed
Hooks and lines (HL) Number of fishing days Number of hooks deployed -
Longlines (LL) Number of hooks deployed Number of sets -
Other gears (OT) Number of days at sea - -
Pole-and-lines (PL) Number of fishing days Number of sets Number of day-poles
Purse seines (PS) Number of fishing hours Number of sets Number of successful/null sets

For each stratum, the data coverage – i.e., the percentage (%) of catch/effort sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates. The spatial and temporal resolutions, catch units, and level of extrapolation vary according to the fishery category.

Category Temporal resolution Spatial resolution Catch unit Extrapolation
Surface fisheries Month 1° grid area Live weight equivalent M
Longline fisheries Month or finer for the SC 5° grid area or finer for the SC Numbers or live weight equivalent M
Coastal fisheries Year or finer Irregular areas Numbers or live weight equivalent O

Documentation describing the extrapolation procedures (including raising factors for logbook coverage) is also required and must be routinely submitted. A template for reporting information on sampling procedures is available in the document IOTC-2021-WPDCS17-27.

Data dimensions

Catch main elements
Effort main elements
Source coverage

Reporting form details

Form 3CE

Geo-referenced size frequencies

Description

Monthly estimates of size-frequencies of the catch retained and discarded by fishing fleet, fishery, grid area, species, and sex.

Conservation and Management Measures

  • Res. 15/01 (Annex II) – On the recording of catch and effort data by fishing vessels in the IOTC area of competence
  • Res. 15/02 (para. 5) – On mandatory statistical reporting requirements for IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs)
  • Res. 17/05 (para. 6) – On the conservation of sharks caught in association with fisheries managed by IOTC
  • Res. 18/02 (para. 3) – On management measures for the conservation of blue shark caught in association with IOTC fisheries
  • Res. 18/05 (para. 8) – On management measures for the conservation of the billfishes: striped marlin, black marlin, blue marlin and Indo-Pacific sailfish

Contents

Measures of individual sizes of fish for the IOTC species, common sharks, and other bycatch species. Straight length measurements made with a calliper or measuring board are recommended over fish weights and vary according to fish groups: (i) lower-jaw fork length for billfish, (ii) upper-jaw fork length for tunas, mackerels, sharks, and all other bycatch fish species with forked or lunate tails, (iii) standard length for bycatch fish species with rounded or truncate tails, and (iv) disc width for rays. The Secretariat further recommends the use of length intervals for the IOTC species and most commonly caught sharks along with maximum length intervals and ranges of valid values which are used to filter and consolidate the size-frequency datasets made available to support the IOTC process (see Recommended measurements).

Sampling coverage shall be set to at least one (1) fish measured by tonne caught by fishery and species, with samples being representative of all the periods and areas fished. For each stratum, the data coverage – i.e., the percentage (%) of catch/effort sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates. In addition, raised estimates of the size samples must be reported to the Secretariat to account for bias due to unrepresentative sampling. Documents covering sampling and raising procedures must be provided for each fishery and species.

Reporting form details

Form 4SF

AFAD-related activities

Description

Daily activities conducted around AFADs, including catches retained and discarded.

Conservation and Management Measures

  • Res. 23/01 (para. 11 and Annex II) – On the management of anchored fish aggregating devices (AFADs)

Contents

Geographic position and description of each fishing activity conducted around each AFAD along with estimates of retained catches and discards in numbers or live weight equivalent for the IOTC species, common sharks, and other bycatch species.

Data dimensions

Activity main stratum
Catch main stratum
Source coverage

Reporting form details

Form 3AA

DFOB-related activities

Description

Operational activities conducted by purse seine and support vessels on DFOBs and buoys.

Conservation and Management Measures

  • Res. 15/02 (para. 6c) – On mandatory statistical reporting requirements for IOTC Contracting Parties and Cooperating Non-Contracting Parties (CPCs)
  • Res. 19/02 (para. 11 and Annex III) – Procedures on a fish aggregating devices (FADs) management plan

Contents

When present, information on buoy identifier, knowledge of the buoy position, and type of activity conducted on the buoy. For each DFOB, information on materials (i.e., presence of plastic or metal), dimensions (i.e., length, width, and height), and presence of mesh with value of mesh size for both the surface (i.e., raft) and subsurface (i.e., tail) components. Finally, species-specific estimates of catches retained and discarded in numbers or live weight equivalent for the IOTC species, common sharks, and other bycatch species.

Data dimensions

Buoy and DFOB main stratum
  • Vessel IOTC number
  • Vessel name
  • Month
  • Day of month
  • UTC time
  • Latitude (in decimal degrees)
  • Longitude (in decimal degrees)
Catch main stratum
  • Vessel IOTC number
  • Vessel name
  • Month
  • Day of month
  • UTC time
  • Latitude (in decimal degrees)
  • Longitude (in decimal degrees)
  • Species
  • Types of fate
  • Catch units

Reporting form details

Form 3DA

Daily buoy positions

Description

Daily positions of operational buoys equipping DFOBs in large-scale purse seine fisheries.

Conservation and Management Measures

Daily positions of active buoys equipping FADs and natural floating objects for each purse seine vessel

  • Res. 19/02 (para. 24) – Procedures on a fish aggregating devices (FADS) management plan

Contents

Single daily buoy position (latitude and longitude in decimal degrees) for each of the buoys monitored by each purse seine vessel. Each buoy is identified by its unique identifier which is a concatenation of the acronym of the buoy commercial model (e.g., ISD+, M3+, T8E) followed by 5-9 digits depending on the buoy model.

Data dimensions

  • Month
  • Day of month
  • Vessel IOTC number
  • Vessel name

Reporting form details

Form 3BU

Fishing craft statistics

Description

Annual number of active fishing vessels by gear, boat type, preservation, and size class.

Conservation and Management Measures

  • UNFSA – Article 4 of the Annex I of the United Nations Fish Stocks Agreement

Contents

Estimates of the numbers of both artisanal and industrial fishing vessels involved in fishing activities during the year, stratified by boat type, mechanisation type, fish preservation method, and refrigeration storage system. For each stratum, the data coverage – i.e., the percentage (%) of catch/effort sampled – derived from the coverage type must be reported to assess the representativeness and quality of the estimates.

Reporting form details

Form 2FC

Quality control procedure

Metadata and data standards

Evaluating the adherence of data submissions to the formats and standards set by the IOTC is essential to uphold the consistency and quality of the data managed by the Secretariat. It is the responsibility of the CPCs and other data providers to ensure the completeness of all metadata and data fields provided to the Secretariat as well as to use the IOTC codelists that build on several international standards and are available from the IOTC data reference catalogue.

The IOTC data reference catalogue is composed of five reference data domains:

  • The administrative and geospatial domains which include codelists for vessel flags, data reporting countries, fishing fleets, CPCs, and several spatial layers used to report information on fishing grounds;

  • The fisheries and fishing technologies domain which include several codelists used to describe the IOTC fisheries, vessels, gears and configurations, as well as fishing devices (e.g., floating objects) and materials;

  • The biological and morphometric domain which includes the IOTC species codelist mostly built on the ASFIS list of species for fishery statistics purposes as well as some code lists used to report information on sampling methods and morphometric measurements;

  • The data and metadata domain which regroups the codelists used to characterise the elements of the datasets, the data sources, types of processings that can be applied, and coverage types;

  • The legacy and external references domain which includes some historical codelists of the IOTC and some international reference codes from FAO, CWP, FIRMS, IUCN, and UN.

Data submission validators

Some validators have been designed to assess the data quality based on the reporting forms.

List of acronyms

AFAD Anchored Fish Aggregating Device
CC IOTC Compliance Committee
CMM Conservation and Management Measure
CPC IOTC Contracting Parties and Cooperating Non-Contracting Parties
CWP Coordinating Working Party on fishery statistics
DFAD Drifting Fish Aggregating Device
EC European Commission
EEZ Exclusive Economic Zone
EMS Electronic Monitoring Systems
ETP Endangered, Threatened and Protected species
EU European Union
FAD Fish Aggregating Device
FOB Floating object
GT Gross Tonnage
IOTC Indian Ocean Tuna Commission
IUU Illegal, Unreported or Unregulated
NGO Non-governmental organisation
LOA Length overall
RAV IOTC Record of Authorised Vessels
REMP Regional Electronic Monitoring Program
RFMO Regional Fisheries Management Organisation
ROS IOTC Regional Observer Scheme
SC IOTC Scientific Committee
UK United Kingdom of Great Britain and Northern Ireland
UN United Nations
WP Working Party

Glossary

A

Anchored Fish Aggregating Device

A fish aggregating device tethered to the bottom of the ocean. It usually consists of a very large buoy and it is anchored to the bottom of the ocean with a chain (Res. 19/02).

Archival tag

Implanted fish tag that detects and records (‘archives’) environmental variables (e.g., water temperature) and location over time. Synonym to data storage tag.

Artisanal fishery

Traditional fishery that involves fishing households (as opposed to commercial companies), using relatively small amounts of capital and energy, relatively small fishing vessels (if any), making short fishing trips close to shore, mainly for local consumption. In practice, definition varies between countries, e.g., from gleaning or a one-man canoe in poor developing countries, to more than 20 m trawlers, seiners, or longliners in developed ones. Artisanal fisheries can be subsistence or commercial fisheries, providing for local consumption or export. They are sometimes referred to as small-scale fisheries (FAO 2005).

Artisanal fishery (IOTC)

Fishery composed of fishing vessels of less than 24 m length overall that exclusively operate in the exclusive economic zone of their flag state, i.e., not recorded in the IOTC Record of Authorised Vessels. Synonym to coastal fisheries (Res. 15/02).

Artisanal fishing vessel (IOTC)

Fishing vessel less than 24 m in length overall operating inside the exclusive economic zone of a flag State and catching tuna or tuna-like species in the IOTC area of competence.

Associated school

The fish school is associated with a topographic structure (e.g., seamount), an anchored or a drifting floating object, including man-made rafts such as fish aggregating devices and live animals in motion (e.g., whale sharks, cetaceans).

B

Bycatch

Discarded catch plus incidental catch (Alverson et al. 1994).

Bycatch species (IOTC)

All species, other than the 16 species listed in Annex B of the IOTC Agreement, caught or interacted with by fisheries for tuna and tuna-like species in the IOTC area of competence. A bycatch species includes those non-IOTC species which are (a) retained (byproduct), (b) incidentally taken in a fishery and returned to the sea (discarded); or (c) incidentally affected by interacting with fishing equipment in the fishery, but not taken.

Byproduct

A species taken incidentally in a fishery while fishing for the target species that has some commercial value and is retained for sale.

C

Coastal fishery (IOTC)

Fishery composed of fishing vessels of less than 24 m length overall that exclusively operate in the exclusive economic zone of their flag state, i.e., not recorded in the IOTC Record of Authorised Vessels. Synonym to IOTC artisanal fishery (Res. 15/02).

Conservation and Management Measure

Any measure adopted pursuant to Articles V(2)(c) and IX in the IOTC Agreement, and more generally where not applicable to IOTC such measures that are consistent with international law (IOTC CMMs).

Coordinating working party on fishery statistics

International and interorganizational forum for agreeing common definitions, classifications and standards for the collection of fishery and aquaculture statistics. It has developed common procedures for statistics collation which have streamlined processes and reduced the burden on the statistical offices of national fisheries and aquaculture production, as well as providing technical advice to participating organisations on fishery-related and aquaculture-related statistical matters, and facilitating the publication of methodological and reference documents (CWP).

D

Disc width

Length of a ray measured as the maximum straight distance between wing tips.

Discards

All non-retained catch, including individuals released alive or discarded dead (Alverson et al. 1994).

Drifting fish aggregating device

Fish aggregating device not tethered to the bottom of the ocean typically composed of a floating structure (such as a bamboo or metal raft with buoyancy provided by buoys, corks, etc.) and of a submerged structure (made of canvass, ropes, etc.) (Res. 19/02).

Drifting longline

Longline kept near the surface or at a certain depth by means of regularly spaced floats. Drifting longlines may be of considerable length, and the snoods are usually longer and more widely spaced than for the bottom longlines. Some drifting longlines are set vertically, each line hanging from a float at the surface. They are usually worked in groups of several lines operated by a single boat (Nédélec and Prado 1999).

Driftnet

Type of gillnet that is not fixed to the seabed but allowed to drift with the current. Synonym to drift gillnet (https://www.fao.org/fishery/en/geartype/220/en).

E

Elasmobranchs

Subclass of chondrichthyes or cartilaginous fish, including modern sharks (superorder Selachii), skates, rays, and sawfish (superorder Batoidea) (Wikipedia).

Engine power

Power that an engine can put out, generally expressed in kilowatt (kw) or horsepower (hp).

Exclusive economic zone

An area beyond and adjacent to the territorial sea, subject to the specific legal regime established in the United Nations Convention on the Law of the Sea, which provides that it is not to extend beyond 200 nm from the baselines from which the breadth of the territorial sea is measured.

F

Fish aggregating device

A permanent, semi-permanent or temporary object, structure or device of any material, man-made or natural, which is deployed and/or tracked, for the purpose of aggregating target tuna species for consequent capture (Res. 19/02).

Fisher

An individual who engages in fishing activities for the purpose of deriving a livelihood, generating a revenue or pursuing sport or recreation. A full-time, part-time or occasional fisher receives some or all of their livelihood from fishing or spends some or all of their working time in that occupation. A sport or recreational fisher (or angler) conducts fishing in pursuit of sport or recreation (CWP Handbook).

Fishery

An activity leading to harvesting of fish. It may involve capture of wild fish or raising of fish through aquaculture (FAO fishery glossary).

Fishery (IOTC) {iotcfishery}

The IOTC fishery emerges from the combination of the fishery purpose, area of operation, size of the fishing vessels, the gear and its gear configuration, and the target species (see section on Terminology).

Fishery vessel

Mobile floating platform of any kind and size, operating in fresh, brackish or marine waters which are used for catching, harvesting, searching, transporting, landing, preserving and/or processing fish, shellfish and other aquatic organisms, residues and plants (CWP Handbook).

Fishing capacity

The ability of a vessel or fleet of vessels to catch fish. Fishing capacity (capacity output) can be expressed more specifically as the maximum amount of fish over a period of time (year, season) that can be produced by a fishing fleet if fully utilised, given the biomass and age structure of the fish stock and the present state of the technology (Pascoe and Greboval 2003).

Fishing effort (effective)

Adjusted measure of effort to take account of differences in fishing power and efficiency and ensure proportionality with fishing mortality, and when two or more kinds of gear are used or when the same gear is used for example by different classes of vessel or métier, the respective efforts are adjusted to some common standard before being aggregated across all classes (strata) (CWP Handbook).

Fishing effort (nominal)

General measure of effort used to quantify the unadjusted, total effort units exerted on a stock in a given time period by a fishery, gear or métier (CWP Handbook).

Fishing logbook

A permanently bound logbook issued by the flag State of a vessel and required for any purpose relating to fishing or related activities, with irremovable pages, each of which is consecutively numbered and printed with an applicable serial number and/or an electronic logbook, being computerised record of information and data relating to fishing or related activities in such template as may be required, including under any conservation and management measure.

Fishing mode

A specific practice or method of conducting a fishing operation or searching for fish within a fishery, fishing sector or region. A fishing mode may also be associated with a métier (CWP Handbook).

Fishing power

Effectiveness of a vessel’s fishing effort relative to the effectiveness of other vessels.

Fishing vessel

Fishery vessel only engaged in catching operations. The term “non-fishing vessel” applies to vessels performing other functions related to fisheries; this includes vessels providing supplies, motherships, fish carriers, and vessels involved in fisheries resources protection, aquaculture operations, and vessels rendering assistance or conducting fisheries related research or training (Thermes et al. 2003).

Flag state

The State in which a vessel is registered, providing it is only registered in one State.

Fork length

Length of a fish measured as the straight distance between the tip of the snout and the fork of the tail.

Free school

The fish school is not associated with any anchored or drifting floating object. Synonym to free-swimming school or unassociated school.

G

Gear

The general name for the equipment used for fishing. This might include lines, nets, warps, floats, deck equipment and any other specific fishing items (Thermes et al. 2023).

Gillnet

Type of passive fishing gear consisting of panels of net held vertically in the water column, either in contact with the seabed or suspended from the sea surface, such that fish attempting to swim through the net are entangled. The mesh size of the net determines the size range of fish caught, as smaller fish can swim through the meshes and larger fish are not enmeshed (https://www.fish.wa.gov.au/).

Gross tonnage

Dimensionless measure of the overall size of a ship (Thermes et al. 2023).

H

Handline

Fishing method in which a line with a hook, usually baited, is lowered into the water from a drifting, anchored or moving fishing vessel or from a jetty, pier or rock on the shore overlooking the water (Bjarnason 1992).

High-seas

All parts of the sea that are not included in the exclusive economic zone, in the territorial sea or in the internal waters of a State, or in the archipelagic waters of an archipelagic State (UNCLOS).

I

Industrial fishery

Fishery that (i) catches fish from large and medium-sized vessels fitted out with mechanised methods of operating the fishing gear and installations for preservation of fish on board, (ii) process the catch either in land base or on board – in which cases the vessels are provided with appropriate processing installations, and (iii) distribute the fish products around the country and abroad using mechanised means of transportation adapted for fish and fish products. All these activities are generally organised for the financial benefit of the companies or organisations operating the fishing vessels, processing plants, and fish product transportation (Thermes et al. 2023).

Industrial fishery (IOTC)

Fishery composed of industrial fishing vessels following the IOTC definition.

Industrial fishing vessel

Large vessel, typically of 24 m in length and over, engaged in catching operations, outfitted with mechanised methods of operating the fishing gear and installations for preservation of fish on board (Thermes et al. 2023).

Industrial fishing vessel (IOTC)

Vessel recorded in the IOTC Record of Authorised Vessels, i.e., of 24 m length overall and over, or of less than 24 m length overall that operates in waters outside the Economic Exclusive Zone of her flag State, including auxiliary, supply and support vessels (Res. 19/04).

IOTC active vessel list

The list of vessels having operated in the IOTC area of competence in a given year, including fishing and non-fishing vessels of 24 m length overall and over, or of less than 24 m length overall that operated in waters outside the economic exclusive zone of the flag State (Res. 10/08).

IOTC Agreement

The 1993 Agreement for the establishment of the Indian Ocean Tuna Commission (IOTC Agreement)

IOTC area of competence

The Indian Ocean (defined for the purpose of the IOTC Agreement as being FAO Statistical Areas 51 and 57), and adjacent seas, north of the Antarctic Convergence, insofar as it is necessary to cover such seas for the purpose of conserving and managing stocks that migrate into or out of the Indian Ocean. In 1999, the Commission extended the western boundary of the IOTC statistical area from 30ºE to 20ºE, thus eliminating the gap in between the areas covered by the IOTC and ICCAT (FAO Fisheries Geonetwork Platform).

IOTC record of authorised vessels

The list of vessels authorised to operate in the IOTC Area of Competence in a given time period, including fishing and non-fishing vessels of 24 m length overall and over, or of less than 24 m length overall that may operate in waters outside the economic exclusive zone of the flag State. These vessels are referred to as authorised fishing vessels (AFVs) (Res. 19/04).

IOTC species

Any or all of the 16 tuna and tuna-like species listed in Annex B of the IOTC Agreement.

IOTC stocks

The populations of the IOTC species which are located in the IOTC area of competence or migrate into or out of the area IOTC Agreement.

Instrumented buoy

A buoy with a clearly marked with a unique reference number allowing identification of its owner and equipped with a satellite tracking system to monitor its position (Res. 19/02).

L

Landing

Weight of what is landed at a landing site. May be different from the catch which includes the discards (FAO fishery glossary).

Large-scale driftnets

Drift gillnets or other nets or a combination of nets that are more than 2.5 km in length whose purpose is to enmesh, entrap, or entangle fish by drifting on the surface of or in the water column.

Length overall

Distance in a straight line parallel to the design waterline, between the foremost point of the bow and the aftermost point of the stern (Thermes et al. 2023).

Line fishing

Fishing methods that use fishing lines in one form or another, including handlines, hand reels, powered reels, pole-and-lines, droplines, longlines, trotlines, and trolling lines.

Live weight equivalent

Weight derived from the landed or product weight by the application of certain factors and designed to represent the actual weight of the fishery product as it was taken from the water and before being subjected to any processing or other operations (Eurostat).

Longline fishery (IOTC)

Fishery undertaken by vessels recorded in the IOTC Record of Authorised Vessels that use a longline gear (Res. 15/02).

Longline

A fishing gear in which branch lines (called snoods or gangions) carrying baited or unbaited hooks are attached to a longer main line at regular intervals. A snood is a short length of line, attached to the main line using a clip or swivel, with the hook at the other end. Longlines are classified mainly by where they are placed in the water column. They can be laid on the bottom or suspended horizontally at a predetermined depth with the help of surface floats. The main lines can be as long as 150 km and have several thousand hooks (FAO fishery glossary).

Lower-jaw fork length

Length of a fish measured as the straight distance between the tip of the lower jaw and the fork of the tail.

M

Metadata

Description of the the content, context and provenance of datasets in a standardised and structured manner, typically describing the purpose, origin, temporal characteristics, geographic location, authorship, access, and conditions and terms of use of a dataset (UK data service).

N

Neritic

Designating, or of, the ecological zone (neritic zone) of the continental shelf extending from low tide to a depth of around 180 m.

Net tonnage

Dimensionless measure of the useful capacity of a ship (Thermes et al. 2023).

Nominal catches

Officially declared aquatic organisms captured during fisheries and expressed as live weight equivalent. Nominal catches do not include unreported catches, such as unreported discards, and may differ considerably from the real catch (Eurostat).

Non-target species

Species that are unintentionally taken by a fishery or not routinely assessed for fisheries management.

O

Oceanic

Open-ocean waters beyond the edge of the continental shelf.

Operational buoy

Any instrumented buoy, previously activated, switched on and deployed at sea on a drifting FAD or log, which transmits position and any other available information such as echo-sounder estimates (Res. 19/02).

P

Pelagic

Inhabiting surface waters rather than the sea floor. Usually applied to free-swimming species such as tunas and sharks.

Pole-and-line fishing

A fishing technique in which surface schooling fish are attracted to the vessel and driven into very active feeding behaviour by throwing live or dead bait into the water and spraying water onto the sea surface to simulate the escape behaviour of small preys. The fish lured with a line and a hook attached to a pole and pulled off the water by manual or powered devices (FAO fishery glossary).

R

Retained catches

Estimated component of the catch which is retained on board during a fishing trip (CWP).

Round weight

Weight of the whole fish before processing or removal of any part (FAO fishery glossary).

Purse seine

Nets characterized by the use of a purse line at the bottom of the net. The purse line enables the net to be closed like a purse and thus retain all the fish caught (Nédélec and Prado 1990).

S

Semi-industrial fishery

Fishery that (i) catches fish from medium- (and/or small-) sized vessels fitted out with mechanised methods of operating the fishing gear, (ii) process the catch in land bases, and (iii) distributed the fish and fish products around a limited area, and in exceptional cases only for export. These activities are aimed at the financial benefit of the companies or organisations operating the fishing vessels, processing plants, and transport facilities (Thermes et al. 2023).

Semi-industrial fishing vessel

Medium-sized vessel, typically of 12 m in length but less than 24 m in length, engaged in catching operations, outfitted with mechanised methods of operating the fishing gear (Thermes et al. 2023).

Semi-industrial fishing vessel (IOTC)

Commercial fishing vessel of length overall comprised between 15 and 24 m and exclusively operating in the exclusive economic zone of the flag state, or of length less than 24 m and operating on the high seas or in exclusive economic zones other than the one from the flag state (IOTC-2023-WPDCS19-07_Rev1).

Set longline

Longline consisting of a main line set either horizontally on or near the bottom or less commonly near the surface (Nédélec and Prado 1990).

Size-frequency

The number of individuals in a catch or catch sample in each group of sizes (size intervals).

Small-scale fishery

Fishery characterised in most cases by fishing vessels with non-mechanized propulsion systems (sails and oars) or low-horsepower outboard or inboard engines, use of passive fishing methods, manual operation of fishing gear (setting, shooting and hauling) and the absence of electronic fish-finding and navigational devices (Tietze et al. 2000). From a socio-economic perspective, small-scale fisheries can be broadly categorised as a dynamic and evolving sector employing labour intensive harvesting, processing and distribution technologies to exploit marine and inland water fishery resources. The activities of this sub-sector, conducted full-time or part-time, or just seasonally, are often targeted on supplying fish and fishery products to local and domestic markets, and for subsistence consumption (FAO 2004).

Standard length

Length of a fish measured as the straight distance between the tip of the snout to the end of the caudal skeleton (FAO fishery glossary).

Subsistence fishery

Subsistence fishery is a fishery where the fish caught are consumed directly by the families of the fishers rather than being bought by middle-(wo)men and sold at the next larger market (FAO 1999).

Support vessel

Non-fishing vessel supporting fishing operations and in particular assisting purse seine fishing vessels in the location of tuna schools and in the the deployment, monitoring and retrieving of buoys and drifting fish aggregating devices. Synonym to supply vessel, auxiliary vessel or tender vessel.

Surface fishery

Fishing activity to target surface-swimming species.

Surface fishery (IOTC)

Fishery undertaken by vessels recorded in the IOTC Record of Authorised Vessels other than longline fisheries; in particular purse seine, pole-and-line, gillnet, handline, and trolling vessels (Res. 15/02).

T

Tonnage

A measure of the size or capacity of a ship, representing a dimensionless function of volume which is defined by internationally agreed formulae (Thermes et al. 2023).

Trolling line

Simple line, provided with natural or artificial bait and trailed near the surface or at a certain depth by a vessel. Several lines are usually towed at the same time, by using outriggers (Nédélec and Prado 1990).

U

Upper-jaw fork length

Length of a fish measured as the straight distance between the tip of the upper jaw and the fork of the tail.