Marine Flora and Fauna of the eastern United States: Acanthocephala

The phylum Acanthocephala (intestinal worm parasites of vertebrates) of the Atlantic coast of the United States comprises 43 species and 20 genera belonging to three orders: Echinorhynchida, Neoechinorhynchida, and Polymorphida. Adults are exclusively intestinal parasites of vertebrates. This study includes those species found in vertebrates of marine and estuarine environments along the North American Atlantic coast between Maine and Texas. Species that can be found within that geographical range and those that typically infect freshwater fishes but that are occasionally present in marine or estuarine hosts are also included. The taxonamy, anatomy, natural history, and ecology of the phylum Acanthocephala are discussed, and an illustrated key to the genera is presented. Techniques, an annotated systematic treatment of all 43 species, and a systematic index are included. No systematic decisions will be made at this time, but areas where such decisions are pending will be indicated and discussed for future reports. (PDF file contains 32 pages.)

Marine Flora and Fauna of the Eastern United States: Copepoda, Cyclopoida: Archinotodelphyidae, Notodelphyidae, and Ascidicolidae

This manual includes an introduction to the general biology, a selected bibliography, and an illustrated key to 11 genera and 17 species of copepods of the Crustacea, Subclass Copepoda, Order Cyclopoida, Families Archinotodelphyidae, Notodelphyidae and Ascidicolidae, associated with ascidians from the Atlantic Coast of the United States. Species distributed from the Gulf of Maine to Long Island Sound are emphasized. An annotated systematic list, with statements of the world distribution and new records of association with hosts, and a systematic index are also provided. (PDF file contains 44 pages.)

Variability in the air-sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data

Two high-frequency (HF) radar stations were installed on the coast of the south-eastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage of currents in the area for the first time. This has made it possible to quantitatively assess the air-sea interaction patterns and timescales for the period 2009-2010. The analysis was conducted using the Barnett-Preisendorfer approach to canonical correlation analysis (CCA) of reanalysis surface winds and HF radar-derived surface currents. The CCA yields two canonical patterns: the first wind-current interaction pattern corresponds to the classical Ekman drift at the sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that local winds play an important role in driving the upper water circulation. The wind-current interaction timescales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in waters of the continental shelf and slope of the south-eastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.

Influence of the Azores high on sea level pressure and wind, and on precipitation, in the Eastern Tropical Pacific Ocean

ENGLISH: Intensification of the Azores high pressure cell in mid-year, with concomitant air flow from the Caribbean into the Pacific, is shown to be responsible for a secondary minimum of precipitation observed along the tropical Pacific coast of the Americas, and to have a measurable effect on wind and precipitation several hundred kilometers offshore. SPANISH: La intensificación de la célula de alta presión de las Azores a mediados del año, y la corriente de aire concomitante que entra al Pacífico procedente del Caribe, se demuestra que es la causante de un mínimo secundario de precipitación observado a lo largo de la costa tropical de las Américas en el Pacífico y que tiene un efecto mensurable sobre el viento y la precipitación varios cientos de kilómetros mar afuera. (PDF contains 23 pages.)

Migrations of yellowfin and skipjack tuna in the Eastern Pacific Ocean as determined by tagging experiments, 1952-1964

ENGLISH: Totals of 59,547 tagged yellowfin and 90,412 tagged skipjack were released during 1952-1964 throughout the range of the fishery in the eastern Pacific Ocean during that period. Most of the fish were released from commercial baitboats, either on regular fishing trips or on chartered trips to catch fish for tagging. There we re 8,397 yellowfin and 4,381 skipjack returned from these releases. There appear to be two main groups of yellowfin in the eastern Pacific Ocean. There is considerable intermingling among the fish of the two groups, however. The fish of the northern group (west coast of Baja California, Gulf of California, and Revillagigedo Islands) first appear in the Revillagigedo Islands in about April, and migrate north along the Baja California coast during the spring and summer and south along that coast during the fall. Recruits to the southern group (Tres Marias Islands to northern Chile) appear at many points or continuously along most of the coast. The fish which first appear in the northern Panama Bight in April migrate rapidly northwest to Central America and Mexico and south to the Gulf of Guayaquil. There also appear to be two main groups of skipjack in the eastern Pacific Ocean. The fish of the northern group (west coast of Baja California, Gulf of California, and Revillagigedo Islands ) perform about the same migration as do the yellowfin of the same area, but most of the skipjack apparently then migrate to the central Pacific Ocean during the fall and/or winter. Recruits to the southern group (Central America to northern Chile) appear mostly in or near the Panama Bight. The fish which first appear in the northern Panama Bight in April migrate rapidly northwest to Central America and south to the Gulf of Guayaquil. The proportions which migrate in these directions vary considerably from year to year, this perhaps being dependent on differences in the sea-surface temperatures. SPANISH: Durante el período de 1952-1964 se liberó a través de todos los límites de distribución de la pesquería en el Océano Pacífico oriental un total de 59,547 aleta amarilla y 90,412 barriletes marcados. La mayoria de los peces fueron liberados de barcos de carnada comerciales, o en viajes regulares de pesca o en viajes en los que se fletaron los barcos para capturar atunes y marcarlos. De estas líberaciones se recapturaron 8,397 aleta amarilla y 4,381 barriletes. Parece que haya dos grupos principales de aleta amarilla en el Océano Pacífico oriental. Sin embargo, existe una entremezcla considerable entre los peces de los dos grupos. Los peces del grupo septentrional (costa occidental de Baja California, Golfo de California y Islas Revillagigedo) aparecen primero en las Islas Revillagigedo alrededor de abril, y durante la primavera y el verano se desplazan al norte a lo largo de la costa de Baja California y durante el otoño al sur a lo largo de la costa. Los reclutas del grupo meridional (Islas Tres Marias hasta el norte de Chile) aparecen en muchas partes o continuamente a lo largo de la mayoría de la costa. Los peces que aparecen primero en la región septentrional del Panamá Bight en abril se desplazan rápidamente al noroeste a la América Central y México y al sur al Golfo de Guayaquil. Parece también que existen dos grupos principales de barrilete en el Océano Pacífico oriental. Los peces del gr upo septentrional (costa occidental de Baja California, Golfo de California e Islas Revillagigedo ) realizan casi la misma migración que el atún aleta amarilla de la misma área, pero aparentemente la mayor parte del barrilete se desplaza luego al Océano Pacífico central durante el otoño y/o en el invierno. Los reclutas al grupo meridional (América Central al norte de Chile) aparecen en su mayoría en el Panamá Bight o cerca a este lugar. Los peces que aparecen primero en la región septentrional del Panamá Bight en abril se desplazan rápidamente al noroeste a la América Central y al sur al Golfo de Guayaquil. Las proporciones que se desplazan en estas direcciones varían considerablemente de año a año; tal vez esto depende en las diferencias de temperatura de la superficie del mar. (PDF contains 227 pages.)

The El Nino of 1972-1973 in the Eastern Tropical Pacific Ocean

ENGLISH: Beginning in February 1972 the usual seasonal cooling of the surface water of the eastern Pacific Ocean in the region of the Peru Current and along the equator failed to develop. By July tropical coastal and equatorial island stations and ships crossing the equator were recording sea-surface temperatures which were 6° to 8°F (3.3°-4.4°C) above the long-term mean. The anomalies spread over most of the eastern tropical Pacific and westward into the central equatorial Pacific through September. During October surface temperatures at coastal stations along South America were returning to normal, but in November and December 1972 temperatures rose rapidly again, with a near-record temperature anomaly of 8.1°F (4.2°C) above the long-term mean recorded at Puerto Chieama, Peru (7°42'S-79°27'W). After January 1973 sea-surface temperatures began returning to normal over most of the eastern tropical Pacific, and by March 1973 the El Nino had completed its cycle. Monthly sea-surface temperature anomalies over the eastern tropical Pacific are discussed to show the extent and magnitude of warming. Annual temperature profiles at several South American coastal and equatorial island stations are compared with temperature profiles for the 1957-1958 and 1965 EI Nino years. Characteristics of the temperature anomaly profiles at Puerto Chicama during several very warm years for the 1925-1972 period are also compared. Finally, meteorological factors contributing to a relaxation of the southeast trade winds and to the decreased unwilling along the coast of South America in 1972-1973 are examined. SPANISH: A comienzos de febrero de 1972, no se registró el enfriamiento común estacional del agua superficial del Océano Pacífico oriental en la región de la Corriente del Perú y a lo largo del ecuador. En julio las estaciones tropicales, costeras y de las islas ecuatoriales, y los barcos que cruzaban la linea ecuatorial registraron temperaturas superficiales del mar de 6° a 8°F (3.3°-4.4°C) más altas que la media a largo plazo. Las anomalías se esparcieron sobre la mayoría del Pacífico oriental tropical, y al oeste en el Pacífico central ecuatorial. En octubre, las temperaturas superficiales de las estaciones costaneras a lo largo de Sudamérica volvieron a la normalidad, pero en noviembre y diciembre de 1972, las temperaturas de nuevo ascendieron rápidamente con una anomalía de temperatura que alcanzó 8.1°F (4.2°C) sobre la media a largo plazo registrada en Puerto Chicama, Perú (7°42'S-79°27'W). Después de enero 1973 las temperaturas de la superficie del mar volvieron rápidamente a la normalidad en la mayoría del Pacífico oriental tropical y en marzo de 1973 el Niño había completado su ciclo. Se discuten las anomalías mensuales de las temperaturas de la superficie del mar en el Pacífico oriental tropical para indicar la extensión y magnitud del calentamiento. Los perfiles anuales de temperatura en varias estaciones costeras y de las islas ecuatoriales sudamericanas se comparan con los perfiles de temperatura de los años en que ocurrió el Niño en 1957-1958 y 1965. Se comparan también las características de los perfiles de las anomalías de temperatura en Puerto Chicama durante varios años muy cálidos para el período de 1925-1972. Finalmente, se examinan los factores meteorológicos que contribuyen al debilitamiento de los vientos alisios del sudeste y a la reducción del afloramiento a lo largo de la costa sudamericana en 1972-1973. (PDF contains 48 pages.)

Growth of yellowfin tuna, Thunnus albacares, in the Eastern Pacific Ocean based on otolith increments

ENGLISH: The growth of yellowfin tuna in the eastern Pacific is described in terms of several measurements taken from the fish and their otoliths (sagittae). Equations are also developed to predict age from the readily available dimensions of fork length and head length. The data for all of these relationships were obtained from a sample of 196 fish collected during 1977 through 1979 from purse seiners fishing north of the equator and east of 137°W. The fork-length range of the sample was 30-170 cm. The number of increments on a sagitta of each fish was used as a direct estimate of its age in days. The correspondence between increments and days has been validated for yellowfin in the length range of 40-110 cm. Circumstantial evidence indicates that the relationship also applies in the intervals of 0-40 cm and 110-170 cm. This circumstancial evidence was derived from: 1) literature on validated increments during early growth for other species, 2) knowledge that structures assumed to be daily increments on yellowfin otoliths have subsequently been validated in the corresponding zone on bluefin otoliths, and 3) a comparison of the growth curve based on increments to others obtained from length frequency modal analysis. Based on this information the age estimates over the entire size range of sampled fish are believed to be accurate. In addition to the general growth and age-predictive relationships, the major conclusions of the study are that: 1) Sexually dimorphic growth exists in terms of fork length, fish weight and the length of the otolith counting path for the entire data set. Examination of the data for 1977 and 1979 also revealed that the fork-length growth of each sex differed within years. 2) For combined sexes there were significant differences among the fork-length growth curves for yellowfin sampled in different years. 3) Yellowfin caught inshore (within 275 miles of the coast) were heavier than those caught offshore for fork lengths between 30 and 110 cm. The situation was reversed for lengths greater than 110 cm. 4) Back-calculated spawning months were distributed uniformly throughout the year in 1974 and 1977, but in 1975-1976 and 1978 spawning activity was apparently concentrated in the latter half of the year. SPANISH: El crecimiento del atún aleta amarilla en el Pacífico oriental se describe en términos de varias medidas obtenidas de peces y otolitos (sagita). Se formularon también ecuaciones para pronosticar la edad, según las dimensiones fácilmente disponibles de la longitud horquilla y longitud de la cabeza. Los datos de todas estas relaciones fueron obtenidos mediante una muestra de 196 peces recolectados desde 1977hasta 1979, en barcos cerqueros que estaban pescando al norte de la línea ecuatorial y al este de los 137°W. El intervalo de la longitud horquilla de la muestra fue de 30-170 cm. Se empleó el número de incrementos en la sagita de cada pez como un estimado directo de la edad en días. Se ha comprobado la relación entre los incrementos y los días en el intervalo de longitud de 40-110 cm del aleta amarilla. La evidencia circunstancial indica que se aplica también la relación a los intervalos de 0-40 cm y 110-170 cm. Esta evidencia circunstancial se dedujo: 1) de las publicaciones sobre incrementos comprobados de otras especies durante el primer crecimiento, 2) del conocimientoque las estructuras que se supone son incrementos diarios en los otolitos del aleta amarilla han sido comprobadas luego en la parte correspondiente de otolitos del aleta azul y 3) por una comparación de la curva de crecimiento, basada en incrementos relacionados a otras curvas obtenidas según el análisis modal frecuencia-talla. Se cree, basados en esta información, que las estimaciones de la edad sobre toda la amplitud de talla de los peces muestreados, es acertada. Además de la relación del crecimiento general y del pronóstico de la edad, las principales conclusiones de este estudio son: 1) En toda la serie de datos existe el crecimiento sexualmente dimórfico en términos de longitud horquilla, peso del pez y longitud del plano de conteo del otolito. El examen de los datos de 1977 y 1979, revelan también que el crecimiento longitud horquilla de cada sexo es diferente en los años. 2) En los sexos combinados hubo diferencias significativas entre las curvas de crecimiento longitud horquilla del aleta amarilla muestreado en diferentes años. 3) El aleta amarilla capturado cerca a la costa (en las primeras 275 millas) fue más pesado que el capturado en las aguas mar afuera, correspondiente a la longitud horquilla entre 30 y 110 cm. La situación fue inversa para tallas de más de 110 cm. 4) En 1974 y 1977, los meses retrocalculados del desove se distribuyeron uniformemente durante el año, pero en 1975-1976 y 1978, la actividad del desove se concentró aparentemente en el último semestre del año. (PDF contains 62 pages.)

Genetic variation between outer-coastal and fjord populations of Pacific herring (Clupea pallasii) in the eastern Gulf of Alaska

Pacific herring (Clupea pallasii) from the Gulf of Alaska were screened for temporal and spatial genetic variation with 15 microsatellite loci. Thirteen collections were examined in this study: 11 from Southeast Alaska and 2 from Prince William Sound, Alaska. Although FST values were low, a neighbor-joining tree based on genetic distance, homogeneity, and FST values revealed that collectively, the Berners Bay and Lynn Canal (interior) collections were genetically distinct from Sitka Sound and Prince of Wales Island (outer-coastal) collections. Temporal genetic variation within regions (among three years of Berners Bay spawners and between the two Sitka Sound spawners) was zero, whereas 0.05% was attributable to genetic variation between Berners Bay and Sitka Sound. This divergence may be attributable to environmental differences between interior archipelago waters and outer-coast habitats, such as differences in temperature and salinity. Early spring collections of nonspawning Lynn Canal herring were nearly genetically identical to collections of spawning herring in Berners Bay two months later—an indication that Berners Bay spawners over-winter in Lynn Canal. Southeast Alaskan herring (collectively) were significantly different from those in Prince William Sound. This study illustrates that adequate sample size is needed to detect variation in pelagic fish species with a large effective population size, and microsatellite markers may be useful in detecting low-level genetic divergence in Pacific herring in the Gulf of Alaska.

Abundance and distribution of the eastern North Pacific Steller sea lion (Eumetopias jubatus) population

The eastern Steller sea lion (Eumetopias jubatus) population comprises animals that breed along the west coast of North America between California and southeastern Alaska. There are currently 13 major rookeries (>50 pups): five in southeastern Alaska, three in British Columbia, two in Oregon, and three in California. Overall abundance has increased at an average annual rate of 3.1% since the 1970s. These increases can largely be attributed to population recovery from predator-control kills and commercial harvests, and abundance is now probably as high as it has been in the last century. The number of rookeries has remained fairly constant (n=11 to 13) over the past 80 years, but there has been a northward shift in distribution of both rookeries and numbers of animals. Based on the number of pups counted in a population-wide survey in 2002, total pup production was estimated to be about 11,000 (82% in southeastern Alaska and British Columbia), representing a total population size as approximately 46,000−58,000 animal

Nineteenth-century Ship-based Catches of Gray Whales, Eschrichtius robustus, in the Eastern North Pacific

The 19th century commercial ship-based fishery for gray whales, Eschrichtius robustus, in the eastern North Pacific began in 1846 and continued until the mid 1870’s in southern areas and the 1880’s in the north. Henderson identified three periods in the southern part of the fishery: Initial, 1846–1854; Bonanza, 1855–1865; and Declining, 1866–1874. The largest catches were made by “lagoon whaling” in or immediately outside the whale population’s main wintering areas in Mexico—Magdalena Bay, Scammon’s Lagoon, and San Ignacio Lagoon. Large catches were also made by “coastal” or “alongshore” whaling where the whalers attacked animals as they migrated along the coast. Gray whales were also hunted to a limited extent on their feeding grounds in the Bering and Chukchi Seas in summer. Using all available sources, we identified 657 visits by whaling vessels to the Mexican whaling grounds during the gray whale breeding and calving seasons between 1846 and 1874. We then estimated the total number of such visits in which the whalers engaged in gray whaling. We also read logbooks from a sample of known visits to estimate catch per visit and the rate at which struck animals were lost. This resulted in an overall estimate of 5,269 gray whales (SE = 223.4) landed by the ship-based fleet (including both American and foreign vessels) in the Mexican whaling grounds from 1846 to 1874. Our “best” estimate of the number of gray whales removed from the eastern North Pacific (i.e. catch plus hunting loss) lies somewhere between 6,124 and 8,021, depending on assumptions about survival of struck-but-lost whales. Our estimates can be compared to those by Henderson (1984), who estimated that 5,542–5,507 gray whales were secured and processed by ship-based whalers between 1846 and 1874; Scammon (1874), who believed the total kill over the same period (of eastern gray whales by all whalers in all areas) did not exceed 10,800; and Best (1987), who estimated the total landed catch of gray whales (eastern and western) by American ship-based whalers at 2,665 or 3,013 (method-dependent) from 1850 to 1879. Our new estimates are not high enough to resolve apparent inconsistencies between the catch history and estimates of historical abundance based on genetic variability. We suggest several lines of further research that may help resolve these inconsistencies.

Quahogs in Eastern North America: Part II, History by Province and State

The northern quahog, Mercenaria mercenaria, ranges along the Atlantic Coast of North America from the Canadian Maritimes to Florida, while the southern quahog, M. campechiensis, ranges mostly from Florida to southern Mexico. The northern quahog was fished by native North Americans during prehistoric periods. They used the meats as food and the shells as scrapers and as utensils. The European colonists copied the Indians treading method, and they also used short rakes for harvesting quahogs. The Indians of southern New England and Long Island, N.Y., made wampum from quahog shells, used it for ornaments and sold it to the colonists, who, in turn, traded it to other Indians for furs. During the late 1600’s, 1700’s, and 1800’s, wampum was made in small factories for eventual trading with Indians farther west for furs. The quahoging industry has provided people in many coastal communities with a means of earning a livelihood and has given consumers a tasty, wholesome food whether eaten raw, steamed, cooked in chowders, or as stuffed quahogs. More than a dozen methods and types of gear have been used in the last two centuries for harvesting quahogs. They include treading and using various types of rakes and dredges, both of which have undergone continuous improvements in design. Modern dredges are equipped with hydraulic jets and one type has an escalator to bring the quahogs continuously to the boats. In the early 1900’s, most provinces and states established regulations to conserve and maximize yields of their quahog stocks. They include a minimum size, now almost universally a 38-mm shell width, and can include gear limitations and daily quotas. The United States produces far more quahogs than either Canada or Mexico. The leading producer in Canada is Prince Edward Island. In the United States, New York, New Jersey, and Rhode Island lead in quahog production in the north, while Virginia and North Carolina lead in the south. Connecticut and Florida were large producers in the 1990’s. The State of Tabasco leads in Mexican production. In the northeastern United States, the bays with large openings, and thus large exchanges of bay waters with ocean waters, have much larger stocks of quahogs and fisheries than bays with small openings and water exchanges. Quahog stocks in certified beds have been enhanced by transplanting stocks to them from stocks in uncertified waters and by planting seed grown in hatcheries, which grew in number from Massachusetts to Florida in the 1980’s and 1990’s.

Quahogs in Eastern North America: Part I, Biology, Ecology, and Historical Uses

The northern quahog, Mercenaria mercenaria, ranges along the Atlantic Coast of North America from the Canadian Maritimes to Florida, while the southern quahog, M. campechiensis, ranges mostly from Florida to southern Mexico. The northern quahog was fished by native North Americans during prehistoric periods. They used the meats as food and the shells as scrapers and as utensils. The European colonists copied the Indians treading method, and they also used short rakes for harvesting quahogs. The Indians of southern New England made wampum from quahog shells, used it for ornaments and sold it to the colonists, who, in turn, traded it to other Indians for furs. During the late 1600’s, 1700’s, and 1800’s, wampum was made in small factories for eventual trading with Indians farther west for furs. The quahoging industry has provided people in many coastal communities with a means of earning a livelihood and has provided consumers with a tasty, wholesome food whether eaten raw, steamed, cooked in chowders, or as stuffed quahogs. More than a dozen methods and types of gear have been used in the last two centuries for harvesting quahogs. They include treading and using various types of rakes and dredges, both of which have undergone continuous improvements in design. Modern dredges are equipped with hydraulic jets and one type has an escalator to bring the quahogs continuously to the boats. In the early 1900’s, most provinces and states established regulations to conserve and maximize yields of their quahog stocks. They include a minimum size, now almost universally a 38-mm shell width, and can include gear limitations and daily quotas. The United States produces far more quahogs than either Canada or Mexico. The leading producer in Canada is Prince Edward Island. In the United States, New York, New Jersey, and Rhode Island lead in quahog production in the north, while Virginia and North Carolina lead in the south. Connecticut and Florida were large producers in the 1990’s. The State of Campeche leads in Mexican production. In the northeastern United States, the bays with large openings, and thus large exchanges of bay waters with ocean waters, have much larger stocks of quahogs and fisheries than bays with small openings and water exchanges. Quahog stocks in certifi ed beds have been enhanced by transplanting stocks to them from stocks in uncertified waters and by planting seed grown in hatcheries, which grew in number from Massachusetts to Florida in the 1980’s and 1990’s.

Trends and Potential Interactions Between Pinnipeds and Fisheries of New England and the U.S. West Coast

Long-term trends in the abundance and distribution of several pinniped species and commercially important fisheries of New England and the contiguous U.S. west coast are reviewed, and their actual and potential interactions discussed. Emphasis is on biological interactions or competition. The pinnipeds include the western North Atlantic stock of harbor seals, Phoca vitulina concolor; western North Atlantic gray seals, Halochoerus grypus; the U.S. stock of California sea lions, Zalophus californianus californianus; the eastern stock of Steller sea lions, Eumetopias jubatus; and Pacific harbor seals, Phoca vitulina richardii. Fisheries included are those for Atlantic cod, Gadus morhua; silver hake, Merluccius bilinearis; Atlantic herring, Clupea harengus; the coastal stock of Pacific whiting, Merluccius productus; market squid, Loligo opalescens; northern anchovy, Engraulis mordax; Pacific her-ring, Clupea pallasi; and Pacific sardine, Sardinops sagax. Most of these pinniped populations have grown exponentially since passage of the U.S. Marine Mammal Protection Act in 1972. They exploit a broad prey assemblage that includes several commercially valuable species. Direct competition with fisheries is therefore possible, as is competition for the prey of commercially valuable fish. The expanding pinniped populations, fluctuations in commercial fish biomass, and level of exploitation by the fisheries may affect this potential for competition. Concerns over pinnipeds impacting fisheries (especially those with localized spawning stocks or at low biomass levels) are more prevalent than concerns over fisheries’ impacts on pinnipeds. This review provides a framework to further evaluate potential biological interactions between these pinniped populations and the commercial fisheries with which they occur.

The Oyster Industry of Eastern Mexico

Mexico has an oyster industry of substantial size, ranking about sixth in the world. In 1993, among the top ten oyster producers, Korea, Japan, the United States, China, and France ranked ahead of Mexico, while the Philippines, Australia, Canada, and New Zealand trailed it (Fig. 1). On its east coast, the species landed is the eastern oyster, Crassostrea virginica, while on its west coast C. corteziensis, C. iridescens, and the Pacific oyster, C. gigas, are landed. During the last 10-15 years, annual production often was at least 50,000 t of shelled oysters, or nearly 1.5 million bushels (Anonymous, 1995), with the great preponderance (90%) coming from a series of lagoons connecting with the Gulf of Mexico along the east coast (Fig. 2) and the remainder produced on the west coast.

King Mackerel, Scomberomorus cavalla, Mark-Recapture Studies Off Florida's East Coast

King mackerel, Scomberomorus cavalla, were tagged and released from eastern Florida between 1985 and 1993. Recapture trends from these studies indicate an increase in tag returns from areas north of the release sites, along with a decrease in recaptures from coastal waters in the Florida Keys and Gulf of Mexico, since earlier king mackerel tagging studies completed in the late 1970's. The data indicate that eastern Florida waters may maintain resident king mackerel. Cyclical tag return patterns were noted along eastern Florida and in North Carolina. The proportion of mixing of presently defined king mackerel stocks along eastern Florida may vary yearly. Comparison of king mackerel tags show internal anchor tags to have a higher percentage of return and lower percentage of tag loss than dorsal dart tags.