History of the Atlantic Pearl-Oyster, Pinctata imbricata, Industry in Venezuela and Colombia, with Biological and Ecological Observations

In the 1500���s, the waters of Venezuela and to a lesser extent Colombia produced more natural pearls than any place ever produced in the world in any succeeding century. Atlantic pearl-oysters, Pinctata imbricata R��ding 1798, were harvested almost entirely by divers. The pearls from them were exported to Spain and other European countries. By the end of the 1500���s, the pearl oysters had become much scarcer, and little harvesting took place during the 1600���s and 1700���s. Harvesting began to accelerate slowly in the mid 1800���s and has since continued but at a much lower rate than in the 1500���s. The harvesting methods have been hand collecting by divers until the early 1960���s, dredging from the 1500���s to the present, and hardhat diving from 1912 to the early 1960���s. Since the mid 1900���s, Japan and other countries of the western Pacific rim have inundated world markets with cultured pearls that are of better quality and are cheaper than natural pearls, and the marketing of natural pearls has nearly ended. The pearl oyster fishery in Colombia ended in the 1940���s, but it has continued in Venezuela with the fishermen selling the meats to support themselves; previously most meats had been discarded. A small quantity of pearls is now taken, and the fishery, which comprised about 3,000 fishermen in 1947, comprised about 300 in 2002.

Descriptions of new genera, species and subspecies of birds from Panama, Colombia, and Ecuador

The first of January, 1912, E. A. Goldman, of the Biological Survey, Department of Agriculture, was again detailed on the Smithsonian Biological Survey of the Canal Zone. He returned to Panama in January and remained there until the last of June passing most of this period in collecting birds and mammals on the slopes of Mount Pirri on the Pacific side of eastern Panama, near the Colombian border...(Document contains 27 pages)

Emergency dam at Pedro Miguel, Panama Canal (ca. 1914)

Leonard Carpenter Panama Canal Collection. Photographs: Dredging, Soldiers, and Ships. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

U.S. Favorite, Pedro Miguel Lock - Old Timers Trip through the Canal, Jan. 20, 1928

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

80 C 146 U.S. Aeroplane carrier "Saratoga" and French cruiser "Joan D'Arc" in Pedro Miguel Lock - Panama Canal - 2/7/28

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

Changes in the chloride content of ground water in Pinellas County, Florida between 1947 and 1956

In December 1956 the U. S. Geological Survey, in cooperation with the Florida Geological Survey and the Board of County Commissioners of Pinellas County, collected waterlevel and chloride content of water in 94 wells in Pinellas County. First sampled in 1947, resampling and reanalyzing the water from these wells was used to determine the change in the chloride content of the ground water from 1947 to 1956. The chloride content of ground water is generally a reliable indication of the contamination of ground water by sea water, as 90 percent of the dissolved solids of sea water are chloride salts. (PDF contains 15 pages.)

Observations on the spawning of four species on tuna (Neothunnus macropterus, Katsuwonus pelamis, Auxis thazard and Euthynnus lineatus) in the Eastern Pacific Ocean, based on the distribution of their larvae and juveniles

ENGLISH: Knowledge of spawning habits is useful in the elucidation of the life history, ecology and population structure of tropical tunas, and is essential to the sound management of these resources. Until recently, little was known concerning the spawning of tunas, or about the distribution of their larval and juvenile stages, in the Eastern Pacific Ocean. Nichols and Murphy (1944) reported the capture off Colombia of young scombroids ultimately identified as frigate mackerel, Auxis thazard (Schaefer and Marr, 1948a). Fowler (1944) reported the capture off Manzanillo, Mexico of two young tunas, one of which is definitely and the other most likely Neothunnus macropterus (Klawe, 1959). In 1947, young of N. macropterus, K. pelamis, A. thazard and E. lineatus were caught offshore from Central America (Schaefer and Marr, 1948a, 1948b, and Schaefer, 1948). Further collections of young N. macropterus, A. thazard and E. lineatus were made in the same general area in the spring of 1949 (Mead, 1951). In January and February 1955, Clemens (1956) carried Out experiments in rearing young tunas, E. lineatus and A. thazard, in shipboard aquaria, using fish caught off Central America. Matsumoto (1958) reported captures of larval N. macropterus and K. pelamis in the area along the 120th meridian of west longitude. Klawe (1958 and 1961b) reported captures of larval N. macropterus and Auxis from the Revillagigedo Islands. Captures of young Auxis and E. lineatus in the Gulf of Panama in January 1922 during the Dana Expedition have recently been reported by Matsumoto (1959). Capture of juveniles of K. pelamis, E. lineatus and Auxis in the area off tropical Mexico and in the area of outlying islands during the SCOT Expedition has been reported by Klawe (1960a). SPANISH: El conocimiento sobre los h��bitos del desove es ��til para el esclarecimiento de la historia natural, ecolog��a y estructura de las poblaciones de atunes tropicales, y es esencial para la acertada administraci��n de estos recursos. Hasta hace poco tiempo no se sab��a mucho sobre el desove de los atunes o acerca de la distribuci��n de sus larvas y juveniles en el Oc��ano Pac��fico Oriental. Nichols y Murphy (1944) informaron sobre la captura frente a Colombia de esc��mbridos j��venes ��ltimamente identificados como melva, Auxis thazard (Schaefer y Marr, 1948a). Fowler (1944) tambi��n inform�� sobre la captura de dos atunes j��venes frente a Manzanillo, M��xico, uno de los cuales era definitivamente Neothunnus macropterus y el otro era lo m��s probable que tambi��n lo fuera (Klawe, 1959). En 1947 se capturaron espec��menes juveniles de N. macropterus, K. pelamis, A. thazard y E. lineatus frente a la Am��rica Central (Schaefer y Marr, 1948a, 1948b, y Schaefer, 1948). Otras recolecciones de ejemplares j��venes de N. macropterus, A. thazard y E. lineatus fueron hechas en la misma ��rea general durante la primavera de 1949 (Mead, 1951). En enero y febrero de 1955, Clemens (1956) efectu�� experimentos de crianza de atunes j��venes, E. lineatus y A.. thazard, en acuarios a bordo para lo que emple�� peces capturados frente a la Am��rica Central. Matsumoto (1958) inform�� sobre capturas de larvas de N. macropterus y K. pelamis en el ��rea a lo largo del meridiano 120 de longitud oeste. Klawe (1958 y 1961b) ha dado cuenta tambi��n de capturas de larvas de N. macropterus y Auxis en las Islas Revillagigedo. Matsumoto (1959) ha informado recientemente acerca de capturas de ejemplares j��venes de Auxis y E. lineatus en el Golfo de Panam�� en enero de 1922 durante la Expedici��n Dana. Klawe (1960a) inform�� as�� mismo que durante la Expedici��n SCOT se capturaron juveniles de K. pelamis, E. lineatus y Auxis en el ��rea frente a la zona tropical de M��xico y en la regi��n de las islas alejadas del continente.

Changes in the size structure of the yellowfin tuna population of the tropical eastern Pacific Ocean from 1947 to 1955

ENGLISH: Morphometric studies by Godsil (1948), Godsil and Greenhood (1951), Royce (1953) and Schaefer (1952, 1955) have indicated that the yellowfin tuna of the Eastern Pacific are distinct from those of the Central Pacific. Tagging of yellowfin tuna by the California Department of Fish and Game, and by the Inter-American Tropical Tuna Commission in the Eastern Pacific, and by the Pacific Oceanic Fishery Investigations in the Central Pacific, have not yet revealed any migrations between these areas. Shimada and Schaefer (1956) have compared changes in population abundance and fishing intensity, considering the population in the Eastern Pacific as a separate entity. They conclude " ... the amount of fishing has had a real effect upon the stock of Eastern Pacific yellowfin tuna, taken in the aggregate, over the period studied. The evidence suggests also that for this species the intensity of fishing in some recent years has reached and might have even exceeded the level corresponding to the maximum equilibrium yield." Tagging experiments by the California Department of Fish and Game and by the Inter-American Tropical Tuna Commission have yielded returns in the order of one to five percent (Roedel 1954, and unpublished data of both agencies), a level much lower than that at which fishing intensity would be expected to noticeably affect the population size. These results are probably a reflection of the inadequacies of the present tagging methods, but they could lend doubt to the conclusions of Shimada and Schaefer. It is desirable, therefore, to examine other, independent, evidence as to the effects of fishing on the population. At the high levels of fishing intensity suggested by Shimada and Schaefer, in addition to changes in quantity, measurable changes would be expected to have occurred in the quality of the yellowfin tuna stocks, because the average age and size of the fish would have been reduced by the high mortality rates accompanying high fishing intensities. A continuing regular program of sampling catches and determining their length composition, to assess changes in the size composition of the stocks, was initiated by the Commission in 1954 but direct measurements are not available for the earlier, more dynamic period of growth of the fishery. Consequently, other, more general indications of possible changes in the size composition were sought. SPANISH: Los estudios morfom��tricos efectudos por Godsil (1948), Godsil y Greenhood (1951), Royce (1953) y Schaefer (1952, 1955), han demostrado que el at��n aleta amarilla del Pac��fico Oriental es distinto del que habita el Pac��fico Central. Los experimentos del Departamento de Pesca y Caza de California y de la Comisi��n Interamericana del At��n Tropical en el Pac��fico Oriental, as�� como los de las Investigaciones Pesqueras del Oc��ano Pac��fico en el Pac��fico Central,consistentes en la marcaci��n de atunes aleta amarilla, a��n no han puesto de manifiesto movimientos migratorios entre dichas ��reas. Shimada y Schaefer (1956) han hecho estudios comparativos sobre la abundancia de la poblaci��n y la intensidad de la pesca, considerando a la poblaci��n del Pac��fico Oriental como una entidad separada. Su conclusi��n es que " ... la intensidad de la pesca ha tenido un definido efecto sobre la poblaci��n del at��n aleta amarilla del Pac��fico Oriental, tomada en conjunto, a lo largo del per��odo estudiado. La evidencia de que se dispone sugiere as�� mismo que, por lo que hace a esta especie, la intensidad de la pesca en los ��ltimos a��os ha alcanzado y quiz��s a��n sobrepasado el nivel correspondiente a la m��xima pesca de equilibrio". Los experimentos de mar���caci��n del Departamento de Pesca y Caza de California y de la Comisi��n Interamericana del At��n Tropical han producido recuperaciones ,entre el uno y el cinco por ciento (Roedel 1954 y datos in��ditos de ambos organismos), lo que constituye un nivel mucho m��s bajo de aqu��l en que la intensidad de la pesca podr��a considerarse que afectar��a notablemente el tama��o de la poblaci��n. Estos resultados reflejan probablemente lo inadecuados que son a��n los m��todos de marcaci��n, pero ellos podr��an, quiz��, poner en tela de juicio las conclusiones de Shimada y Schaefer. Por lo tanto,es deseable examinar otras fuentes de evidencia independientes, relacionadas con el efecto que la pesca tiene sobre la poblaci��n. En efecto, si los altos ��ndices de pesca sugeridos por Shimada y Schaefer son correctos, es de esperar que, adem��s de los cambios en la magnitud de la poblaci��n, se hayan producido otros, concomitantes y sensibles, en la calidad de los stocks de at��n aleta amarilla, puesto que tanto el promedio de edad como el de tama��o de los individuos habr��an disminu��do debido a las elevadas tasas de mortalidad inherentes a las altas intensidades de pesca. En 1954 la Comisi��n inici�� un programa ininterrumpido para tomar muestras y determinar en ellas las frecuencias de tallas y evaluar de este modo los cambios correlativos que tuvieran lugar en los stocks pero, infortunadamente, este sistema de evaluaci��n directa no fu�� practicado en el per��odo anterior, que fu�� precisamente el de r��pida expansi��n de la pesquer��a. En tal virtud, hubo de ser necesario buscar indicios m��s generales referentes a los cambios posibles en la composici��n de tama��os. (PDF contains 20 pages.)

Length-weight relationships of demersal fishes from the upper continental slope off Colombia

Parameters of the length���weight relationship of the form W=aLb are presented for 45 demersal fish species caught on the upper continental slope of the Caribbean Sea off Colombia. The b values varied between 2.13 and 4.97, with the mean b = 3.042 (95% CI, 2.887- 3.196).

Length-weight relationships of demersal fishes from the Gulf of Salamanca, Colombia: [part 2]

The parameters a and b of the length-weight relationship of the form W=aL super(b) are presented for 37 fish species, belonging to 17 families, caught during a demersal trawl survey over the period December 1995 to March 1998 in the Gulf of Salamanca, Colombia

Length-weight relationships of demersal fishes from the Gulf of Salamanca, Colombia

The parameters a and b of the length-weight relationship of the form W=a L super(b) were computed for 46 species caught in a series of demersal trawl hauls over the period 1995-1997 in the Gulf of Salamanca, Colombia.

Tarpon atlanticus in Colombia: a big fish in trouble

The natural history of Tarpon atlanticus (Valenciennes 1846) is reconstructed based on published information. Tarpon is a remarkable fish because of its peculiar larvae, large adult size, migration patterns and its capability to breathe atmospheric air. Destructive fisheries - some using dynamite - have much reduced the population of tarpon along the Caribbean coast of Colombia, and some catch data are presented which document this.

Diet composition of fish species from the southern continental shelf of Colombia

The diet composition of 30 fish species belonging to 16 families from the Pacific Coast of Colombia is described. Benthic crustaceans (37.5%) and bony fishes (23.7%, chiefly demersal) were the most important food items for the fish species analyzed. Data on diet composition of the fish species are presented for the first time which can be a source of information for trophic modeling.

Diet composition and daily ration estimates of selected trawl-caught fishes in San Miguel Bay, Philippines

The diet composition of fish caught in San Miguel Bay, Philippines, in April and May 1993 was studied. The diets of tiger-tooth croaker (Otolithes ruber), commerson's anchovy (Stolephorus commersonii); and the Indian anchovy (Stolephorus indicus) consisted mainly of zooplankton, primarily crustaceans. The stomach content of orangefin ponyfish (Leiognathus bindus) was found to consist mostly of detritus and unidentified materials. Daily rations estimated were: 1.90 g day super(1) for O. ruber of 17.3 g mean body weight (BW), 0.078 g day super(1) for S. commersonii) of 3.8 g mean BW, 0.062 g day super(1) for S. indicus of 3.9 g mean BW and 0.56 g day super(1) for L. bindus of 7.7 g mean BW.