by
G.W. SNOW
Bureau of Commercial Fisheries
United States Department of the Interior
New Orleans, Louisiana 70130, U.S.A.
Abstract
The domestic shrimp fishery, centered in the Gulf States, has expanded rapidly during the past 20 years and is now the most valuable fishery in the United States. Despite the rapid rise in importance of this fishery, detailed statistical information was not available prior to 1955 to meet the needs of government and industry.
This paper describes the methods and procedures used in the collection and publication of detailed statistics in a program developed for the shrimp fishery of the Gulf of Mexico. Statistical data provided by this program are vital to the expanding economic and biological research programs of State and Federal agencies. In addition, industry is supplied with current and accurate information on shrimp supplies, prices, and market conditions, in order to plan their operations.
Development of this program was aided immeasurably by experience gained in a similar program for the North Atlantic fisheries which has been in operation at New England ports for many years.
PROGRAMME DE STATISTIQUES DETAILLEES SUR LES CREVETTES, ETATS DU GOLFE DU MEXIQUE
Résumé
Les pêches nationales de crevettes, concentrées dans les Etats du golfe du Mexique, se sont développées rapidement au cours des vingt dernières années et représentent actuellement, par leur valeur, la principale activité de pêche des Etats-Unis d'Amérique. Malgré l'accroissement rapide de l'importance de ces pêches, on ne dispose pas, pour la période antérieure à 1955, des renseignements statistiques détaillés dont auraient besoin le gouvernement et l'industrie.
L'auteur décrit les méthodes et les procédés utilisés pour recueillir et publier des statistiques détaillées dans le cadre d'un programme intéressant les pêcheries de crevettes du golfe du Mexique. Les données statistiques fournies par ce programme présentent une importance capitale pour les programmes de recherche économique et biologique en voie d'expansion entrepris par des organismes relevant des Etats ou du gouvernement fédéral. En outre, l'industrie reçoit, en vue d'établir le plan des opérations, des renseignements exacts et à jour touchant les disponibilités de crevettes, les prix et la situation du marché.
L'expérience acquise à l'occasion d'un programme analogue pour les pêches de l'Atlantique Nord, qui fonctionne dans les ports de Nouvelle-Angleterre depuis de nombreuses années, a représenté pour l'élaboration de ce programme une aide inestimable.
PROGRAMA ESTADISTICO DETALLADO SOBRE CAMARONES EN LOS ESTADOS DEL GOLFO DE MEXICO
Extracto
La pesquería nacional de camarones, cuyo centro se halla en los Estados del Golfo de México, se ha ampliado rápidamente durante los últimos 20 años y en la actualidad es la pesquería más valiosa de los Estados Unidos de América. No obstante el rápido incremento de esta pesquería, no existía información estadística detallada anterior a 1955 que respondiera a las necesidades del gobierno y de la industria.
En este trabajo se describen los métodos y procedimientos empleados en la recogida y publicación de estadísticas detalladas en un programa desarrollado para la pesquería camaronera del Golfo de México. Los datos estadísticos proporcionados por este programa son vitales para los crecientes programas de investigación económicos y biológicos de los organismos estatales y federales. Además, la industria dispone de información actual y exacta sobre los suministros de camarones, precios y condiciones del mercado para planificar sus operaciones.
Ha ayudado inmensamente al desarrollo de este programa la experiencia obtenida en un programa similar para las pesquerías del Atlántico Norte que se realizó durante muchos años en los puertos de Nueva Inglaterra.
For the past 14 yr, with the exception of one year (1961), shrimp have been the most valuable species in the commercial fisheries of the United States. During 1966, the dockside (ex-vessel) value of shrimp landed exceeded $95 million and was 43 percent greater than the second most valuable species, Pacific salmon. The value of shrimp landed at ports of the Gulf States (West coast of Florida, Alabama, Mississippi, Louisiana and Texas) has ranged from 83 to 91 percent of the total value of domestic shrimp landings during this same period. A sustained and ever increasing demand for shrimp by consumers has been the major factor in the increased value of shrimp and the increased volume of imports and domestic landings. Increases in domestic catches have been achieved by the discovery of new grounds, more intensive fishing effort on the old grounds, and the development of more efficient fishing craft and gear.
Despite the rapid rise in importance of the shrimp fishery after the second world war, detailed statistics on the fishery were lacking. Generally, statistics were collected showing the total annual shrimp landings in each state, catch by types of gear, and the total craft, fishermen and gear operated in the fishery. Information on processed shrimp products, canned, dried and frozen, also were collected on an annual basis. In many instances, individual state severance tax records were the principal source of data on landings. These annual statistics were supplemented, to a degree, by additional information appearing in daily Fishery Products reports issued by the New Orleans Market News office of the Fish and Wildlife Service, U.S. Department of the Interior. In these releases, during the late forties, there were weekly reports of the predominating size of shrimp landed at a few Gulf ports. Beginning in 1950, annual summaries included information on the species composition of shrimp landed at a few of the major Gulf ports which were given daily Market News coverage. While this type of information was of some benefit to industry, the species and count size composition of shrimp landed at these ports could not, in most instances, be considered representative of the total landings for each of the states.
In 1955, funds became available within the Department of Interior, Fish and Wildlife Service, for the establishment of a detailed shrimp statistical program, designed to supply information on the Gulf shrimp fishery for economic and biological research, as well as market news for marketing purposes. This program, from its inception, has been supervised by the Branch of Fishery Statistics office in New Orleans, Louisiana.
An analysis of the information to be collected to meet the needs of both industry and government indicated that the assignment of one employee to each major Gulf port would be adequate. There were no specific laws requiring the submittal of the types of information required in our program, but all dealers and fishermen were briefed on the objectives and methods of the program to insure their co-operation. Perhaps a significant factor in the fine co-operation received from industry is the fact that information supplied by dealers and fishermen in co-operative programs is classified as confidential and, as such, cannot be released to other governmental agencies or individuals without a court order.
2.1 Market news
The market news aspects of the new program presented no major problems. Prior to 1955, contract reporters were employed by the Branch of Market News, New Orleans, Louisiana, to collect data on the daily commercial fishery landings at major Gulf ports. The assignment of Bureau Fishery Reporting Specialists to nearly all major Gulf ports not only expanded the coverage of daily commercial fishery landings but also provided much greater detail; thus the species of shrimp and count-size (number of heads-off shrimp per lb) were recorded, as well as prices at those ports which usually control market activity.
For market news purposes, it is not essential that data on shrimp landed at all Gulf ports be published. The essential factor is that representative comparative data on volume, price, variety, size, etc. be available each day, covering landings during the 24 or 48 h period ending that morning. Speed of dissemination and accuracy are perhaps the most important factors in market news, for it is these reports that provide industry with information necessary for short range or day-to-day planning of their operations. At present, the daily Fishery Products reports issued by the New Orleans Market News office are mailed to approximately 1,200 subscribers in the fishing and allied industries in the U.S.A. and foreign countries.
2.2 Economic research
For economic research, both basic and applied, statistics are necessary which translate the quantities of inputs and outputs into values and cost. Our present program supplies only a part of these statistics, primarily information on outputs. Landings data are published monthly and annually in Shrimp Landings bulletins which show the volume and value, by species and count size, of shrimp landed in each of the Gulf and South Atlantic States, as well as the number of trips and count size composition of catches from major grounds fished by the Gulf shrimp fleet. Additional economic data on other major species as well as shrimp are included in Bureau of Commercial Fisheries publications. Among the more important of these publications are monthly and annual Frozen Fishery Products bulletins which provide information on the freezing and cold storage inventories of most major species, quarterly Fish Sticks, Fish Portions, and Breaded Shrimp bulletin, and the annual digest Fishery Statistics of the United States.
It has not been possible to expand our program to include the collection of such information as the costs of fishing and processing operations, capital investment in plants and vessels, and the costs of obtaining capital and the returns to it. This type of information is necessary in developing and testing management plans.
2.3 Biological research
Biological research requires as much detailed information as the previously discussed activities. The catch, by individual fishing craft, by species and by size, the value of the catch, the area and depth of capture, and a measure of the catch per unit of affort are all needed. In our preliminary analysis, it was determined that the use of automatic data processing equipment would be necessary because of the volume and variety of statistical data to be collected and tabulated. Processing in this manner required that a standard form be devised for the recording of data at the ports and also that code systems be established in order that the recorded data could be put into “machine language”.
3.1 Fishing grounds
The most difficult coding problem involved the development of a system for recording the areas of the Gulf from which shrimp were taken by fishing craft. For our purposes, the Gulf of Mexico was initially divided into a grid of numbered or statistical units, each of one degree of latitude and longitude (Fig. 1). A two digit code was established for reporting depth fished within the statistical units; since the tabulating of catch for each depth fished would prove too voluminous, depths were coded in 5 fm groupings: 1 to 5 fm as 01, 6 to 10 fm as 02, 11 to 15 fm as 03, etc.
During the latter part of 1958, personnel of the Bureau of Commercial Fisheries Biological Laboratory, Galveston, Texas, recommended a revision of the statistical units to facilitate the analysis of Gulf shrimp exploitation data. This recommendation was accepted and the new statistical units (Fig. 2) have been used from 1 January 1959 to the present date. Data coded and tabulated under the original system were readily interchangeable with the new statistical units and there was no loss of comparative data. No changes were made in the system for coding water depths.
GULF OF MEXICO AND WESTERN CARIBBEAN SEA
FWS FISHING GRID ZONES
Fig. 1 U.S. Fish and Wildlife Service fishing grid zones in the Gulf of Mexico and western Caribbean Sea, as used in 1958.
FWS SHRIMP FISHING GRID ZONES
Fig. 2 U.S. Fish and Wildlife Service shrimp fishery grid zones in the Gulf of Mexico and Caribbean Sea, adopted in January 1959.
3.2 Fishing vessels
Compiling data on the catches of individual boats required a numbering system for the boats. Originally, a complete alphabetical listing was made of all craft in the Gulf shrimp fishery; craft were then assigned 5 digit numbers, beginning with 00005, with sufficient spacing between numbers to permit the inclusion of new craft entering the fishery in their proper alphabetical position. Employees at all ports were furnished copies of this listing, known as the Shrimp Vessel Code Book, and were informed of additions, deletions, change of name of vessels, etc., through periodic memoranda issued by the New Orleans office. Beginning in 1961, the official number assigned to vessels (craft of 5 net tons and over) when they were documented by the Bureau of Customs, U.S. Treasury Department, was used for identification. This simplified the preparation of vessel code books and resulted in more accurate reporting. Information on physical characteristics (length, tonnage, horsepower, year built), size of crew, and quantity of gear for individual vessels, identified by name or official number, appear on cards maintained in our data processing system. The use of the official number rather than an arbitrarily assigned number facilitates correlation of catch data with any of these characteristics should the need arise.
3.3 Count size grading and type of landing
Research biologists also requested information on the method by which shrimp are graded for size by dealers, and the condition (heads-on or heads-off) in which shrimp were landed. Data on shrimp graded by the dealer (from random samples taken during unloading, known as “box” weight) are assigned code number “1”; shrimp graded by machine are assigned code number “2”. Code numbers established for the condition of shrimp landed (appearing as “type landing” on our forms) were “1” for heads-on landings, “2” for heads-off, and “3” for landings consisting of both heads-on and heads-off shrimp.
The fact that some shrimp are landed with heads-on and others with heads-off presented a minor problem. While the ideal solution would perhaps have been to record the weight actually landed (heads-on or heads-off), it was felt that this would add appreciably to the volume of data to be published, and, in some instances, prove confusing. It was decided that, since the majority of shrimp were landed in a heads-off condition, our reports, with the exception of the annual Fishery Statistics of the United States, would list landings as heads-off weight (in lb). This, of course, required the use of conversion factors in instances where shrimp are landed with heads on. Prior to 1962, a factor of 1.68 was used for all species, but research indicated that this factor was not accurate (Kutkuhn, 1962). Beginning 1 January 1962, the following factors were used: brown shrimp (Penaeus aztecus), 1.61; pink (P. duorarum and P. brasiliensis), 1.60; white, (P. setiferus), 1.54; seabob (Xiphopenaeus kroyeri), 1.53; and royal red (Hymenopenaeus robustus), 1.80.
The ex-vessel or dockside value of shrimp caught by fishing craft also presented a minor problem. At some Gulf ports there is a practice of charging the vessel for unloading and weighing of catches, by imposing a fixed charge, not related directly to the quantity of shrimp landed by the individual vessel. Such deductions from the gross amount received by the fishing craft are recorded to insure the comparability of ex-vessel value, regardless of the port at which shrimp are landed.
The method of collecting data is similar at all Gulf ports. Each working day, Fishery Reporting Specialists obtain the volume and value, by individual vessel, of shrimp purchased by each dealer the previous day. Data are recorded on Form 2-1839 (Fig. 3) commonly known as a “shrimp schedule” by our staff. The quantity of shrimp landed daily at each port, by species and count size, is required for market news purposes, and the Fishery Reporting Specialist tabulates the data shrimp schedules and transmits it to the New Orleans office by telephone. While a shrimp schedule is prepared for the landings of each and every trip, the same procedure is not used for shrimp landed by ‘boats’ (craft of less than 5 net tons). These boats usually confine their fishing to inside waters, and during the shrimp season in Louisiana they frequently make two trips per day, each day of the week. Data on catches by boats are consolidated, with a shrimp schedule prepared for each statistical unit fished by the fleet. In place of the vessel name on the shrimp schedule, the total number of boats whose catches have been included on the schedule is inserted.
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Fig. 3 Shrimp schedule, used by port agents for Gulf of Mexico shrimp landings.
Each day, the Fishery Reporting Specialist also interviews captains of as many newly arrived shrimp vessels as possible, obtaining from them information on the grounds fished, effort expended, and other information as required to complete Form 2-1840 (Fig. 3). Form 2-1840 is printed on the reverse of Form 2-1839 so that interview data may be directly correlated with the actual volume and value of shrimp landed by the vessel, as obtained from dealer records. Form 2-1839 is the source document for the preparation of data processing cards, and the items appearing at the top of the form are coded for this purpose. The example of a completed form (Fig. 3) indicates the way the coding is accomplished in accordance with information obtained by interview with the captain of the vessel.
The value of catch data depends almost entirely on the care with which information on the grounds fished and fishing effort expended is obtained from the captain of each vessel. With as many as 300 vessels operating out of one port at the peak of a season, complete interview coverage cannot be obtained for all landings. The grounds and depth fished for non-interviewed trips are, in part, estimated by Fishery Reporting Specialists, using several sources of information; dealers unloading the catch of vessels often know the grounds from which the shrimp were taken by a specific vessel; at the time of interviewing a vessel captain, the names of other vessels fishing the same locality are obtained. Some of our Fishery Reporting Specialists also monitor marine radio band to obtain information as to where vessels are fishing, and conversation between vessel captains on this band often includes a discussion of catch rates.
In our program, days fished, based upon a 24-h day, was selected as the effort factor. This is obtained by calculating the total hours of fishing, as reported during the interview, and dividing by 24; the result is expressed to the first decimal place. Hours fished, as reported during the interview, represent the elapsed time from the setting of the trawl each day until it is hauled back aboard the vessel after the final tow. When catches are taken from more than one statistical unit during a trip, effort and catch data are apportioned between areas as indicated in the interview.
At the end of each month, Fishery Reporting Specialists mail all completed Forms 2-1839 and 2-1840 to the Branch of Fishery Statistics office in Arlington, Virginia, where the automatic data processing is accomplished. After processing, the data are published in monthly and annual Gulf Coast Shrimp Data bulletins which are used primarily by biologists engaged in shrimp research. These bulletins contain two major tabulations. The first consists of data on the total shrimp catch (interview and non-interview) landed at Gulf ports, giving the species and size, by statistical unit, depth and number of trips. The second table consists of data for interviewed craft only and contains days fished and species and size of shrimp, by area, depth, and number of trips.
All data processing cards, as well as the original source documents (shrimp schedules), are sent to the Bureau's Galveston Biological Laboratory for storage. Data are thus readily available for processing should the need arise for information not currently tabulated in the present program.
Anderson, W.W., M.J. Lindner and J.E. King, 1950 The shrimp fishery of the southern United States. Fishery Leafl.Fish Wildl.Serv.U.S., (368):17 p.
Johnson, F.F. and M.J. Lindner, 1934 Shrimp industry of the South Atlantic and Gulf States. Investl Rep.U.S.Bur.Fish., (21):83 p.
Kutkuhn, J.H., 1962 Conversion of “whole” and “headless” weights in commercial Gulf of Mexico shrimps. Spec.scient.Rep.U.S.Fish Wildl.Serv.(Fish.), (409):7 p.
