Fabio Carocci, Adele Crispoldi, Juan Ignacio de Leiva & Jacek Majkowski
FAO Fisheries Department
Viale delle Terme di Caracalla
00100 Rome, Italy
E-mail: email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Since 1952 FAO has been collecting annual catch data for all marine and freshwater species including tuna and tuna-like species. These data, grouped by fishing country and FAO statistical area, are mostly being obtained directly from fishing countries.
The Marine Resources Service (FIRM) of the FAO Fisheries Department has independently been collating from the tuna fishery bodies and other regional and national institutions:
catch data for principal market tunas and some billfishes by fishing gear, 5° × 5° square and quarter of year (since 1997).
These statistics are not necessarily official, but are regarded by these institutions as the most representative.
All the above mentioned data are available from FAO's Fisheries Global Information System (FIGIS) in the form of individual values, their plots and maps. In general, the two data sets of tuna nominal catches are very similar. The discrepancies between them and the 5° x 5° catch data are the result of: (i) the latter data only accounting for longline, pole-and-line and purse-seine fishing; (ii) not including catches of unknown or poorly known locations in the latter data (e.g. many artisanal and some commercial fisheries), and (iii) from the exclusion, in the latter data, of those catches that were available not by weight but by number of fish.
Tuna and tuna-like species are very important economically, and a significant source of food. There are approximately 40 species at item or higher taxonomic level for which commercial catches are reported in the Atlantic, Indian and Pacific Oceans and in the Mediterranean and Black Seas. Their global production has increased continuously from less than 0.6 million tonnes in 1950 to nearly 6.1 million tonnes in 2002. In 2001 the estimated value of tuna and tuna-like species at the landing site (US$8.3 billion) accounted for more than 10 percent of the total capture fisheries production. Tunas and tuna-like species are also among the most important commodities in fisheries trade, especially as exports by developing countries. In 2001 exports of tunas and tuna-like species (US$4.9 billion, f.o.b.) represented nearly 9 percent of the total value of fishery exports.
The so-called principal market tuna species are albacore (ALB, Thunnus alalunga), bigeye tuna (BET, T. obesus), Atlantic bluefin tuna (BFT, T. thynnus), Pacific bluefin tuna (PBF, T. orientalis), southern bluefin tuna (SBF, T. maccoyii), skipjack tuna (SKJ, Katsuwonus pelamis) and yellowfin tuna (YFT, Thunnus albacares). These seven species are the most important among the tuna and tuna-like species from the standpoints of both weight and market value. They are landed at numerous locations around the world, traded on a global scale and processed and consumed in many locations worldwide. In 2002, the combined catch of these seven species was approximately 4 million tonnes, which accounted for about two thirds of the total catch of all the tunas and tuna-like species. During 2002 most of the catches of the principal market tuna species were taken from the Pacific (66 percent), followed by the Indian (24 percent) and the Atlantic, Mediterranean and Black Sea combined (10 percent).
More than 80 percent of the nominal global catches of tunas and tuna-like species consists of skipjack and yellowfin, which account for 50 percent and 32 percent of those catches, respectively. Bigeye and albacore represent 10 percent and 6 percent, respectively, while the three remaining species, Atlantic bluefin tuna, Pacific bluefin tuna and southern bluefin tuna, comprise only 2 percent of global catches.
Presently, FAO is the repository of three data sets, accessible by internet, with data on the catches of tunas and tuna-like species:
1) Tunas and tuna-like species in the Capture Production (Fishstat Plus) and Global Capture Production (FIGIS) databases;
2) Global Tuna Nominal Catches; and
3) Atlas of Tuna and Billfish Catches.
The main characteristics of these data sets, their sources and the differences among them are described in the following sections.
2.1 Tunas and tuna-like species in the capture production (Fishstat Plus) and global capture production (FIGIS) databases
Information on world capture fishery production is collected by the FAO Fishery Information, Data and Statistics Unit (FIDI) from national offices that collect fishery statistics, by means of a system of standardized, but country-tailored, forms, which list for each country the species items and the fishing areas. ("Capture fishery production" is the volume of fish catches landed by country or territory of capture, by species or higher taxonomic level, by FAO major fishing areas, and year for all commercial, industrial, recreational and subsistence purposes.) As part of the general inquiry, annual commercial tuna nominal catches, by species and area of capture, are provided by the reporting countries. The data are validated, processed and stored in a database. The data for tunas and tuna-like species can be retrieved by accessing ISSCAAP Group 36, "Tunas, bonitos and billfishes", in the data set "Capture production 1950-2002", downloadable together with Fishstat Plus, a universal software for users' customized retrieval and time series analyses, including graphical tools and tabulations developed by FIDI (http://www.fao.org/fi/statist/FISOFT/FISHPLUS.asp).
The link http://www.fao.org/fi/statist/statist.asp provides on-line access to the same world capture production data through the Fisheries Global Information System (FIGIS) "Global Capture Production (1950 to 2002)" data set. Users can consult the tuna catches time-series online, using the FIGIS Query Panel, which allows them to define complex multicriteria queries and customize the results table. Results can be viewed as a graph, or exported in a standard format.
Data concerning the nominal catches of tunas and tuna-like species are reviewed in collaboration with organizations involved in research on these species. When data reported to FAO/FIDI are not in agreement with those reported to those organizations, the data provided by the national correspondents are, in most cases, replaced by "the best scientific estimates" produced by organizations collecting tuna catch statistics (i.e. ICCAT, IOTC, IATTC and SPC). This approach was adopted in accordance with a recommendation of the Coordinating Working Party on Fishery Statistics. On the other hand, FAO/FIDI is provided by its network of national correspondents with data for some countries (that are not reporting regularly to the Commissions), species (mostly small tunas) and segments of the fishing industry (artisanal fisheries) that are not collected by the respective regional organizations. In recent years, some of these regional organizations collecting tuna catch statistics have relied upon data compiled by FAO to complement the information included in their databases.
2.2 Global tuna nominal catches
The Global Tuna Nominal Catches Database presents the nominal catches (in tonnes) for the principal market tuna species by flag fishing nation, fishing gear, stock and species. These data are available through the Fisheries Global Information System (FIGIS).
The collection of catch statistics for tuna species has been carried out by various organizations involved in research on tunas and tuna-like species for specific species and areas. Such statistics were provided to the Fishery Resources Division (FIR) of FAO's Fisheries Department (FI) for the specific purpose of preparing the Global Tuna Nominal Catches database. The organizations that provided data on nominal catches of tunas and tuna-like species are listed in the Acknowledgements section.
The main difference between these data and those collated by the FAO's Fishery Information, Data and Statistics Unit (FIDI) is that the Capture Production database provides the nominal catches, without distinguishing among different fishing gears and tuna stocks. The main reason for FIR to undertake the task of integrating all collated statistics into one data set was the need for data on nominal catches by stock and fishing gear for management and stock assessment purposes. The classification of the nominal catches by stocks was accomplished in consultation with scientists of other organizations involved in research on tunas and tuna-like species.
Presently, several organizations listed in the Acknowledgement section are providing the nominal catch data in Fishstat Plus format, thus simplifying the collation, compilation and processing of the data received.
These organizations have different coding systems with respect, to fishing gears, species, flag fishing nations, etc., and therefore adjustments were needed in order to standardize the data.
The fishing gears considered in this database were:
other: other types of gear.
Seven species, including a total of 22 stocks, were considered,
yellowfin tuna: Atlantic, Indian, eastern Pacific, western and central Pacific.
The data set includes catches from 1950 to 2002, and for the first time world nominal catches of tuna species can be extracted by flag fishing nation, fishing gear, stock and species.
2.3 Atlas of tuna and billfish catches
The organizations involved in research on tunas and tuna-like species that provide data on nominal catches also collect catch data on spatial distribution.
Such data, with a geographical resolution of rectangles of 5° latitude by 5° longitude ("5×5 rectangles") or higher resolution were provided to the FAO Fishery Resources Division (FIR) for the specific purpose of preparing the interactive Atlas of Tuna and Billfish Catches, which is accessible through FIGIS.
The statistics were collated and integrated into one data set and displayed through the Atlas, which presents the global distribution of 1950 to 2001 catches, by 5×5 rectangles, for those tuna and tuna-like species for which this distribution is generally well known on a global scale. These species consist, as noted above, of the so-called principal market tunas and some billfishes.
In detail, the Atlas shows spatial catches from 1950 to 2001 by:
12 tuna and billfish species,
- albacore (Thunnus alalunga);
- Atlantic bluefin tuna (Thunnus thynnus);
- white marlin (Tetrapturus albidus);
- bigeye tuna (Thunnus obesus);
- black marlin (Makaira indica);
- blue marlin (Makaira nigricans);
- Pacific bluefin tuna (Thunnus orientalis);
- skipjack tuna (Katsuwonus pelamis);
- southern bluefin tuna (Thunnus maccoyii);
- striped marlin (Tetrapturus audax);
- swordfish (Xiphias gladius);
yellowfin tuna (Thunnus albacares).
3 gear types,
Spatial resolution by 5×5 rectangles.
Temporal resolution by quarters.
In some cases, the following adjustments were introduced to the individual data sets before combining them into one data set before showing them in the Atlas:
the catches, in numbers of fish, were converted to units of weight for fisheries for which the conversion factors were given by the data providers; otherwise, the catches in numbers of fish were not included,
catches from 1×1 rectangles were aggregated into those associated with 5×5 rectangles,
catches erroneously assigned to land locations were not included (data providers were notified of these discrepancies, and error investigations are in progress),
for catches reported without quarterly resolution (e.g. Korean longline catches for 1988-1989), catches were included only on charts of annual catches, and the lack of quarterly resolution is clearly indicated in the downloadable data sets,
for each 5×5 rectangle, catches were assigned to the center of the rectangle, if this had not already been done by the providers of the data,
overlaps among data sets were eliminated, and
national data from Japan, the Republic of Korea and Taiwan Province of China were used to supplement spatial catches for bluefin tunas in the Pacific prior to 1970 and for the eastern Pacific Ocean from 1970 to 1997 (the last year for which these data were provided).
For the species included in the Atlas, the catches by area are shown when locations of catch, by 5×5 rectangles, are known or could be assumed as fractions of the nominal catches for all oceans.
The different data sets for the principal market species, with the exception of southern bluefin tuna, have been compared by oceans, and the results are shown in the charts below. The comparison includes data up to 2002, except for the 5×5 rectangle data set, for which only data up to 2000 were available at the time the document was produced.
3.1 Atlantic Ocean
The three data sets are very similar throughout the time series, except for some differences between the 5×5 rectangle data set and the other two data sets during the 1950s.
For the Atlantic industrial fisheries, ICCAT combined data by 5×5 rectangle and quarter and raised the data to the level of its nominal catches. For most small-scale fisheries in the Atlantic, catches that are not reported by 5×5 rectangle and quarter are also assigned to specific rectangles. For this reason, there are only small differences between spatial data and nominal catches.
3.2 Indian Ocean
The trend of the catches of both the Capture Production data set (retrieved through Fishstat Plus) and the Global Tuna Nominal Catches data sets are almost identical. The greatest differences occur during the 1988-1994 period. The differences may be due partially to the different levels of species identification in reporting.
The difference between the Global Tuna Nominal Catches and the 5x5 rectangle data set is much greater, but the trends are very similar. Part of this difference is explained by the fact that the 5x5 rectangle data set includes only catches by LL, PL and PS, whereas the Global Tuna Nominal Catches data set includes also trolling lines and other gears.
However, there are additional important discrepancies between the longline catches of the two data sets. One possible explanation regarding these discrepancies between longline data may be that nominal catch data also include catches of unknown or poorly-known locations, and of many artisanal and some commercial fisheries that are not accounted for in the charts of the Atlas. Such discrepancies also could result from the exclusion, in the Atlas, of catch data that were provided only in numbers of fish (i.e. Japanese longline catches in the Indian Ocean). The latter catches may represent a significant portion of catches in some regions. Effort is underway to convert the data from numbers to weights so they can be included in the Atlas.
3.3 Pacific Ocean
The catches in both the Capture Production data set (retrieved through Fishstat Plus) and the Global Tuna Nominal Catches are practically identical, even though the data sources of the two time series are different. The greatest differences occurred during the early years of the time series (1950-1958), and in 1991, 1992, 2000 and 2001.
The difference between nominal catches and the 5x5 rectangle catches is much greater, mainly because: (1) the coverage of the tuna fleet by observers is not complete; (2) lack of geographical information of illegal, unreported and unregulated fishing (IUU) tuna catches; (3) lack of reports for some of the tuna fleets; (4) exclusion in the Atlas of catch data provided only as numbers of fish; and (5) nominal catch data, including catches with unknown or poorly-known locations, which are not accounted for on the charts of the Atlas. The artisanal component is quite important in the Indian and Pacific Oceans, resulting in the large discrepancies between spatial and nominal catch data. In the eastern Pacific Ocean, for example, catches of vessels of less than 100 gross registered tons (GRT) are not necessarily reported.
With the help of users, several possible improvements and added functionalities have been identified regarding the collections of data sets presently stored and delivered to the public through FIGIS. The following suggestions regarding data content have been made:
possible inclusion of purse-seine catch data disaggregated by modes of fishing for the catch-by-area data set.
The following suggestions regarding functionalities have been made:
averaging functions through years and quarters (or months);
downloading of selected records from main data sets;
enhancement of the quality control, and linking the reference tables to the FIGIS code system to facilitate integration with other FIGIS collections;
discontinuing the use of the present Java-based query panel for Nominal Catches to a more user-friendly HTML query panel.
The following organizations provided data on catches of tunas and billfishes to the Global Tuna Nominal Catches and the Atlas of Tuna and Billfish Catches: Australian Fisheries Management Authority (AFMA), Indian Ocean Tuna Commission (IOTC), International Commission for the Conservation of Atlantic Tunas (ICCAT), Inter-American Tropical Tuna Commission (IATTC), Interim Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC), National Institute of Water and Atmospheric Research (NIWA), National Marine Fisheries Service (NMFS) and the Secretariat of the Pacific Community (SPC). The Food and Agriculture Organization of the United Nations (FAO) and its Fisheries Department are grateful for their collaboration.
Nevertheless, the authors assume full responsibility for any potential problems and mistakes in their compilation and its presentation in the figures.
 See acknowledgements for explanations of abbreviations.
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