999 resultados para CRAB LARVAE


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(PDF contains 6 pages.)

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ENGLISH: The anchoveta, Cetengraulis mysticetus (Günther), is an important bait fish used to capture tunas in the Eastern Tropical Pacific Ocean. Contributions to the early life history of this species in the Gulf of Panama were made by Simpson (1959), who was able to identify deductively the planktonic egg of the anchoveta from 10 other anchovy eggs concurrently present. He also reared these planktonic eggs in the laboratory and described the resultant larvae to the age of 48 hours after hatching. Because of the lack of differences among the anchovy larvae, this description does not permit the identification of anchoveta larvae from those of other engraulid species. Furthermore, while adult specimens are easily recognized, up to the present it has not been possible to extend the identification of the juvenile anchoveta to specimens smaller than about 25 mm. The purpose of this study, therefore, was to identify anchoveta from the time of hatching to about 25 mm. SPANISH: La anchoveta, Cetengraulis mysticetus (Günther), es un importante pez de carnada que se emplea en la captura de los atunes en el Océano Pacífico Oriental Tropical. Simpson (1959) logró identificar deductivamente el huevo planctónico de la anchoveta al separarlo de otros diez huevos de anchoas que se encuentran al mismo tiempo, contribuyendo de esta manera a conocer los primeros estados de la historia natural de esta especie en el Golfo de Panamá. El también estableció un criadero en el laboratorio con estos huevos planctónicos y describió las larvas resultantes hasta la edad de 48 horas después de la eclosión. Debido a que no hay diferencias entre las larvas de las anchoas, esta descripción no permite identificar las larvas de la anchoveta de las otras especies de engráulidos. Más aun, a pesar de que los especímenes adultos son fácilmente reconocibles, hasta ahora no ha sido posible identificar la anchoveta juvenil de menos de unos 25 mm. Consecuentemente, el propósito del presente estudio ha sido el de identificar al anchoveta desde el momento de la eclosión hasta que tiene unos 25 mm.

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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 hábitos del desove es útil para el esclarecimiento de la historia natural, ecología y estructura de las poblaciones de atunes tropicales, y es esencial para la acertada administración de estos recursos. Hasta hace poco tiempo no se sabía mucho sobre el desove de los atunes o acerca de la distribución de sus larvas y juveniles en el Océano Pacífico Oriental. Nichols y Murphy (1944) informaron sobre la captura frente a Colombia de escómbridos jóvenes últimamente identificados como melva, Auxis thazard (Schaefer y Marr, 1948a). Fowler (1944) también informó sobre la captura de dos atunes jóvenes frente a Manzanillo, México, uno de los cuales era definitivamente Neothunnus macropterus y el otro era lo más probable que también lo fuera (Klawe, 1959). En 1947 se capturaron especímenes juveniles de N. macropterus, K. pelamis, A. thazard y E. lineatus frente a la América Central (Schaefer y Marr, 1948a, 1948b, y Schaefer, 1948). Otras recolecciones de ejemplares jóvenes de N. macropterus, A. thazard y E. lineatus fueron hechas en la misma área general durante la primavera de 1949 (Mead, 1951). En enero y febrero de 1955, Clemens (1956) efectuó experimentos de crianza de atunes jóvenes, E. lineatus y A.. thazard, en acuarios a bordo para lo que empleó peces capturados frente a la América Central. Matsumoto (1958) informó sobre capturas de larvas de N. macropterus y K. pelamis en el área a lo largo del meridiano 120 de longitud oeste. Klawe (1958 y 1961b) ha dado cuenta también de capturas de larvas de N. macropterus y Auxis en las Islas Revillagigedo. Matsumoto (1959) ha informado recientemente acerca de capturas de ejemplares jóvenes de Auxis y E. lineatus en el Golfo de Panamá en enero de 1922 durante la Expedición Dana. Klawe (1960a) informó así mismo que durante la Expedición SCOT se capturaron juveniles de K. pelamis, E. lineatus y Auxis en el área frente a la zona tropical de México y en la región de las islas alejadas del continente.

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About 72 species of Sebastes (Family Scorpaenidae) are found along the eastern Pacific coast of North America, some of which are heavily exploited by both commercial and sport fisheries. Because of the large number of species, the identification of early life stages has progressed slowly. The objectives of this study were 1) to rear the larvae of four species of rockfish (Sebastes mystinus, S. carnatus, S. atrovirens, and S. rastrelliger); and 2) to describe the larvae using morphometric measurements, pigmentation patterns, and head spination. Pigmentation was the most useful feature for identification purposes. Two general patterns were found: 1) a short row of ventral midline melanophores on the tail, and none or very little postero-dorsal pigmentation (S. mystinus); and 2) complete ventral midline pigmentation on the tail, and anterior and postero-dorsal melanophores (S. carnatus, S. atrovirens, and S. rastrelliger). With the exception of very early stages of S. carnatus and S. atrovirens, these species can be readily identified. Morphometric proportions and head spination did not show major differences among species. Because of the great similarities found among species in this genus, descriptions from field studies are uncertain to some extent. Laboratory rearings, although difficult, can at least provide early larvae from known species which allow precise identification as well as an estimation ofvariability of characters (e.g., pigmentation) within and between broods.(PDF file contains 22 pages.)

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Larvae of over 50 families of nearshore fishes were taken in oceanic waters about 13 km offshore of the leeward (southwest) coast of Oahu, Hawaii during 1977-78, The five most frequently taken families (Labridae, Parapercidae, Serranidae, Gobiidae, and Carangidae) made up over 50% of the total nearshore larvae. Most other families were taken very infrequently. Comparison of catch data from three types of nets indicated that 1.25-m diameter bongo nets often sampled larvae as well or better than a 3-m Isaacs-Kidd trawl and that smaller, 70-cm diameter bongo nets were often as effective as the larger nets for certain abundant taxa. Only a few taxa showed evidence of seasonal patterns in abundance. Irregular temporal variability in abundance of some taxa may have been related to occasional recent influxes of surface water from closer to shore. Most larvae taken were late preflexion stage or older. Densities of even the most abundant taxa were rarely greater than 0.001 m-3. The nearshore fish larvae were not dominated by taxa with large larvae or with larvae possessing apparent specializations to pelagic existence, Most taxa taken were pelagic spawners as adults, but larvae of demersal spawners were roughly as well represented as demersal spawners are among the nearshore fish fauna. Previous studies of waters closer to shore probably sampled insufficient volumes for any but a few exceptionally abundant taxa. Sampling with volumes filtered of the order of 104-105 m3 will be necessary to determine if the dominant taxa taken by the present study are ever more abundant closer to shore, (PDF file contains 23 pages.)

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We present data on ichthyoplankton distribution, abundance, and seasonality and supporting environmental information for four species of coastal pelagics from the family Carangidae: blue runner Caranx crysos, Atlantic bumper Chloroscombrus chrysurus, round scad Decapterus punctatus, and rough scad Trachurus lathami. Data are from 1982 and 1983 cruises off Louisiana sponsored by the Southeastern Area Monitoring and Assessment Program (SEAMAP). Bioprofiles on reproductive biology, early life history, meristics, adult distribution, and fisheries characteristics are also presented for these species. Maximum abundances of larval blue runner, Atlantic bumper, and round scad were found in July inside the 4O-m isobath, although during the rest of the cruises these species were rarely found together. Larval Atlantic bumper were captured in June and July only; blue runner in May, June, and July; and round scad in all seasons. Atlantic bumper larvae, concentrated mostly off western Louisiana, were by far the most abundant carangid in 1982 and 1983. Larval blue runner were the second most abundant summer-spawned carangid in 1982 and 1983, but their abundance and depth distribution varied considerably between years. Relative abundance of larval round scad off Louisiana was low, and they were captured only west of the Mississippi River delta, although they are reported to dominate carangid populations in the eastern Gulf of Mexico. Rough scad were primarily winter/spring and outer-shelf (40-182 m) spawners. They ranked third in overall abundance, but were the most abundant target carangid on the outer shelf. Ecological parameters such as surface salinity, temperature, and station depth are presented from capture sites for recently hatched larvae <2.5 mm notochord length, except round scad) as well as for all sizes of fish below 14 mm standard length. (PDF file contains 44 pages.)

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We present data on ichthyoplankton distribution, abundance, and seasonality and supporting environmental information for four species of coastal pelagics from the family Clupeidae: round herring Etrumeus teres, scaled sardine Harengula jaguana, Atlantic thread herring Opisthonema oglinum, and Spanish sardine Sardinella aurita. Data are from 1982 and 1983 cruises across the northern Gulf of Mexico sponsored by the Southeastern Area Monitoring and Assessment Program (SEAMAP). This is the first such examination for these species on a multiyear and gulfwide scale. Bioproflles on reproductive biology, early life history, meristics, adult distribution, and fisheries characteristics are also presented for these species. During the summer, larval Atlantic thread herring and scaled and Spanish sardines were abundant on the inner shelf <40 m depth), but were rare or absent in deeper waters. Scaled sardine and thread herring were found virtually everywhere inner-shelf waters were sampled, but Spanish sardines were rare in the north-central Gulf. During 1982, larval Atlantic thread herring were the most abundant of the four target c1upeid species, whereas Spanish sardine were the most abundant during 1983. On the west Florida shelf, Spanish sardine dominated larval c1upeid populations both years. Scaled sardine larvae were the least abundant of the four species both years, but were still captured in 25% of inner-shelf bongo net collections. Round herring larvae, collected February-early June (primarily March-April), were abundant on the outer shelf (40-182 m depth) and especially off Louisiana. Over the 2-year period, outer-shelf mean abundance for round herring was 40.2 larvae/10 m2; inner-shelf mean abundances for scaled sardine, Atlantic thread herring, and Spanish sardine were 14.9, 39.2, and 41.9 larvae/l0 m2, respectively. (PDF file contains 66 pages.)