Precision of age determination of northern offshore spotted dolphins.

We investigated within- and between-reader precision in estimating age for northern offshore spotted dolphins and possible effects on precision from the sex and age-class of specimens. Age was estimated from patterns of growth layer groups i n the dentine and cementum of the dolphins' teeth. Each specimen was aged at least three times by each of two persons. Two data samples were studied. The first comprised 800 of each sex from animals collected during 1973-78. The second included 45 females collected during 1981. There were significant, generally downward trends through time in the estimates from multiple readings of the 1973-78 data. These trends were slight, and age distributions from last readings and mean estimates per specimen appeared to be homogeneous. The largest factor affecting precision in the 1973-78 data set was between-reader variation. In light of the relatively high within-reader precision (trends considered), the consistent between-reader differences suggest a problem of accuracy rather than precision for this series. Within-reader coefficients of variation averaged approximately 7% and 11%. Pooling the data resulted i n an average coefficient of variation near 16%. Within- and between-reader precision were higher for the 1981 sample, and the data homogeneous over both factors. CVs averaged near 5% and 6% for the two readers. These results point to further refinements in reading the 1981 series. Properties of the 1981 sample may be partly responsible for greater precision: by chance there were proportionately fewer older dolphins included, and preparation and selection criteria were probably more stringent. (PDF contains 35 pages.)

South West College, Northern Ireland - technology for employability: FE and skills case studies

Forging links between education and industry

Northern range extension, abundance and distribution of Pacific coastal Bottlenose doplhins (Tursiops truncatus gilli) in Monterey Bay, California

Pacific coastal bottlenose dolphins (Tursiops truncatus gilli) have apparently moved to Monterey Bay as a result of a shift north of their known range. Between 1983 and 1993, 417 sightings were reported off central California. Eighty-four boat-based surveys, between October 1990 and November 1993, resulted in the photo-identification of 68 uniquely marked individuals. School size ranged between 2 and 35 animals (mean = 16.60, S.D. = 7.72). Forty-three (63%) of the dolphins identified were previously photographed in the Southern California Bight before 1989. Jolly-Seber population estimates indicated an increase in the Monterey Bay population from 1990 to 1993. At least 13 of the photo-identified dolphins were present in Monterey Bay throughout the study period. All but two of the calculated coefficients of association were 0.35, indicating a strong bond among resident animals. The occurrence of an El Niño from January 1992 to the end of 1993 may have affected the number of animals present in the bay: mean school size was significantly greater during El Niño.

Description of Early Larvae of Four Northern California Species of Rockfishes (Scorpaenidae: Sebastes) from Rearing Studies

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.)

Early-life-history profiles, seasonal abundance, and distribution of four species of Clupeid larvae from the northern Gulf of Mexico, 1982 and 1983

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.)

Effects of temperature on the biology of the northern shrimp, Pandalus borealis, in the Gulf of Maine

Length-frequency data collected from inshore and offshore locations in the Gulf of Maine in 1966-1968 indicated that ovigerous female northern shrimp (Pandalus borealis) first appeared offshore in August and September and migrated inshore in the fall and winter. Once eggs hatched, surviving females returned offshore. Juveniles and males migrated offshore during their first two years of life. Sex transition occurred in both inshore and oll'shore waters, but most males changed sex offshore during their third and fourth years. Most shrimp changed sex and matured as females for the first time in their fourth year. Smaller females and females exposed to colder bottom temperatures spawned first. The incidence of egg parasitism peaked in January and was higher for shrimp exposed to warmer bottom temperatures. Accelerated growth at higher temperatures appeared to result in earlier or more rapid sex transition. Males and non-ovigerous females were observed to make diurnal vertical migrations, but were not found in near- surface waters where the temperature exceeded 6°C. Ovigerous females fed more heavily on benthic molluscs in inshore waters in the winter, presumably because the egg masses they were carrying prevented them from migrating vertically at night. Northern shrimp were more abundant in the southwestern region of the Gulf of Maine where bottom temperatures remain low throughout the year. Bottom trawl catch rates were highest in Jeffreys Basin where bottom temperatures were lower than at any other sampling location. Catch rates throughout the study area were inversely related to bottom temperature and reached a maximum at 3°C. An increase of 40% in fecundity between 1973 and 1979 was associated with a decline of 2-3°C in April-July offshore bottom temperatures. Furthermore, a decrease in mean fecundity per 25 mm female between 1965 and 1970 was linearly related to reduced landings between 1969 and 1974. It is hypothesized that temperature-induced changes in fecundity and, possibly, in the extent of egg mortality due to parasitism, may provide a mechanism which could partially account for changes in the size of the Gulf of Maine northern shrimp population during the last thirty years. (PDF file contains 28 pages.)

An egg production method for estimating spawning biomass of pelagic fish: Application to the northern anchovy, Engraulis mordax

Fishery scientists engaged in estimating the size of free-swimming populations have never had a technique available to them whereby all the parameters could be estimated from a resource survey and where no parameter values need to be assumed. Recognizing the need for a technique of this kind, the staff of the Coastal Fisheries Resources Division of the Southwest Fisheries Center (SWFC) devised an egg production method for anchovy biomass assessment. Previously, anchovy biomass was estimated by approximate methods derived from a long-time series and anchovy larval abundance, which required about 5 ma of shiptime each year to integrate the area under a seasonal spawning curve. One major assumption used in the larval abundance census method is that there is constant proportionality between larval numbers and spawning biomass. This has now proved to be erroneous. (PDF file contains 105 pages.)

Management of northern fur seals on the Pribilof Islands, Alaska, 1786-1981

This paper includes information about the Pribilof Islands since their discovery by Russia in 1786 and the population of northern fur seals, Cailorhinus ursinus, that return there each summer to bear young and to breed. Russia exterminated the native population of sea Oilers, Enhydra lulris, here and nearly subjected the northern fur seal to the same fate before providing proper protection. The northern fur seal was twice more exposed to extinction following the purchase of Alaska and the Pribilof Islands by the United States in 1867. Excessive harvesting was stopped as a result of strict management by the United States of the animals while on land and a treaty between Japan, Russia, Great Britain (for Canada), and the United States that provided needed protection at sea. In 1941, Japan abrogated this treaty which was replaced by a provisional agreement between Canada and the United States that protected the fur seals in the eastern North Pacific Ocean. Japan, the U.S.S.R., Canada, and the United States again insured the survival of these animals with ratification in 1957 of the "Interim Convention on the Conservation of North Pacific Fur Seals," which is still in force. Under the auspices of this Convention, the United States launched an unprecedented manipulation of the resource through controlled removal during 1956-68 of over 300,000 females considered surplus. The biological rationale for the reduction was that production of fewer pups would result in a higher pregnancy rate and increased survival, which would, in turn, produce a sustained annual harvest of 55,000-60,000 males and 10,000-30,000 females. Predicted results did not occur. The herd reduction program instead coincided with the beginning of a decline in the number of males available for harvest. Suspected but unproven causes were changes in the toll normally accounted for by predation, disease, adverse weather, and hookworms. Depletion of the animals' food supply by foreign fishing Heets and the entanglement of fur seals in trawl webbing and other debris discarded at sea became a prime suspect in altering the average annual harvest of males on the Pribilof Islands from 71,500 (1940-56) to 40,000 (1957-59) to 36,000 (1960) to 82,000 (1961) and to 27,347 (1972-81). Thus was born the concept of a research control area for fur seals, which was agreed upon by members of the Convention in 1973 and instituted by the United States on St. George Island beginning in 1974. All commercial harvesting of fur seals was stopped on St. George Island and intensive behavioral studies were begun on the now unharvested population as it responds to the moratorium and attempts to reach its natural ceiling. The results of these and other studies here and on St. Paul Island are expected to eventually permit a comparison between the dynamics of unharvested and harvested populations, which should in turn permit more precise management of fur seals as nations continue to exploit the marine resources of the North Pacific Ocean and Bering Sea. (PDF file contains 32 pages.)

Molecular diagnosis of distal renal tubular acidosis in Tunisian patients: proposed algorithm for Northern Africa populations for the ATP6V1B1, ATP6V0A4 and SCL4A1 genes

Background: Primary distal renal tubular acidosis (dRTA) caused by mutations in the genes that codify for the H+ -ATPase pump subunits is a heterogeneous disease with a poor phenotype-genotype correlation. Up to now, large cohorts of dRTA Tunisian patients have not been analyzed, and molecular defects may differ from those described in other ethnicities. We aim to identify molecular defects present in the ATP6V1B1, ATP6V0A4 and SLC4A1 genes in a Tunisian cohort, according to the following algorithm: first, ATP6V1B1 gene analysis in dRTA patients with sensorineural hearing loss (SNHL) or unknown hearing status. Afterwards, ATP6V0A4 gene study in dRTA patients with normal hearing, and in those without any structural mutation in the ATP6V1B1 gene despite presenting SNHL. Finally, analysis of the SLC4A1 gene in those patients with a negative result for the previous studies. Methods: 25 children (19 boys) with dRTA from 20 families of Tunisian origin were studied. DNAs were extracted by the standard phenol/chloroform method. Molecular analysis was performed by PCR amplification and direct sequencing. Results: In the index cases, ATP6V1B1 gene screening resulted in a mutation detection rate of 81.25%, which increased up to 95% after ATP6V0A4 gene analysis. Three ATP6V1B1 mutations were observed: one frameshift mutation (c.1155dupC; p.Ile386fs), in exon 12; a G to C single nucleotide substitution, on the acceptor splicing site (c.175-1G > C; p.?) in intron 2, and one novel missense mutation (c. 1102G > A; p. Glu368Lys), in exon 11. We also report four mutations in the ATP6V0A4 gene: one single nucleotide deletion in exon 13 (c.1221delG; p. Met408Cysfs* 10); the nonsense c.16C > T; p.Arg6*, in exon 3; and the missense changes c.1739 T > C; p.Met580Thr, in exon 17 and c.2035G > T; p.Asp679Tyr, in exon 19. Conclusion: Molecular diagnosis of ATP6V1B1 and ATP6V0A4 genes was performed in a large Tunisian cohort with dRTA. We identified three different ATP6V1B1 and four different ATP6V0A4 mutations in 25 Tunisian children. One of them, c.1102G > A; p.Glu368Lys in the ATP6V1B1 gene, had not previously been described. Among deaf since childhood patients, 75% had the ATP6V1B1 gene c. 1155dupC mutation in homozygosis. Based on the results, we propose a new diagnostic strategy to facilitate the genetic testing in North Africans with dRTA and SNHL.

Dynamics of Streptococcus pneumoniae Serotypes Causing Acute Otitis Media Isolated from Children with Spontaneous Middle-Ear Drainage over a 12-Year Period (1999–2010) in a Region of Northern Spain

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The traditional fishery of Ibu project area on the northern portion of the Imo River, Nigeria

A survey carried out on the fishery of the northern portion of Imo basin (known as Ibu project area for the purpose of this study) provided some information on the number and type of fishermen cropping this portion of the Imo River, Nigeria. The population was found to be very mobile with many itinerant or seasonal fishermen. The type of gear in use was studied and a high number of traditional dug-out canoes recorded which shows the ability of the people to make their own canoes. The presence of freshwater shrimps crayfish and clupeids at this upper region of the Imo River was observed

Observations on the purse-seine fishery for Northern bluefin tuna (Thunnus thynnus) in the Eastern Pacific Ocean

ENGLISH: This report presents information on the fishery for bluefin in the northeastern Pacific Ocean derived from purse seiner logbook records and landing statistics. Information on the size composition of the fish in the catch is also presented. The logbook records cover the period 19611980; however, catch statistics and length-frequency data from previous years are also presented. SPANISH: Este informe presenta los datos sobre la pesca del T. thynnus en el Océano Pacífico nordeste, obtenidos de los cuadernos de bitácora de los barcos cerqueros y de las estadísticas de desembarque. Se presenta además la información sobre la composición de talla de los peces en la captura. Los registros de bitácora abarcan el período de 1961 a 1980; no obstante, se presentan además las estadísticas de captura y los datos de la frecuencia de talla de años anteriores. (PDF contains 105 pages.)

Chemical narcosing of fish in northern Cross River

Chemical narcosing of fish was found to be one of the fishing techniques used for harvesting fish stocks in the northern Cross River, Cross River State, Nigeria. The preparation of the fish poison is described. The ichthyotoxic plants used for the fish poisoning were identified and Derris elliptica recommended to be used for the development of piscicides for the removal of unwanted fish in the fish farms

Growth, movement, and attrition of northern bluefin tuna, Thunnus thynnus, in the Pacific Ocean, as determined by tagging

ENGLISH: The growth of northern bluefin tuna is described by a two-stanza model. For fish between 191 and 564 mm in length the Gompertz curve, with values of 581 mm and 4.32 for Loo and K (annual), respectively, is used. The fish between 564 and 1530 mm grow linearly, at the rate of 0.709 mm per day. Age-O fish tagged and released in the western Pacific Ocean have been recaptured in the western, central, and eastern Pacific. The minimum time between release in the western Pacific and recapture in the eastern Pacific is 215 days. Older fish, mostly Land 2-year olds, tagged and released in the eastern Pacific have been recaptured in the eastern and western Pacific. The minimum time between release in eastern Pacific and recapture in the western Pacific is 674 days. The coefficient of natural mortality is estimated from data on growth and ambient temperature to be 0.276 on an annual basis, with 90-percent confidence limits of 0.161 and 0.47L Spawning of northern bluefin takes place only in the western Pacific. Some of the juveniles migrate to the eastern Pacific, where they reside for several months to several years before returning to the western Pacific. The portion of fish which migrate to the eastern Pacific varies among years, and this appears to be an important cause of the annual variation in the catches in the eastern Pacific Ocean. SPANISH: El crecimiento del atún aleta azul del norte es descrito por un modelo de dos estadios. Para los peces de entre 191 y 564 mm de talla se usa la curva de Gompertz, con valores de 581 mm y 4.32 para Loo y K (anual), respectivamente. Los peces de entre 564 y 1530 mm crecen de forma lineal, a 0.709 mm por día. Peces de edad Omarcados y liberados en el Pacífico occidental han sido recapturados en el Pacífico occidental, central, y oriental. La demora mínima entre la liberación en el Pacífico occidental y la recaptura en el Pacífico oriental es de 215 días. Peces mayores, principalmente de 1 ó 2 años de edad, marcados y liberados en el Pacífico oriental han sido re capturados en el Pacífico occidental y oriental. La demora mínima entre la liberación en el Pacífico oriental y la recaptura en el Pacífico occidental es de 674 días. Se estima el coeficiente de mortalidad natural a partir de los datos de crecimiento y temperatura ambiental en un 0.276 anual, con límites de confianza al 90% de 0.161 y 0.471. El aleta azul del norte desova únicamente en el Pacífico occidental. Algunos de los juveniles migran al Pacífico oriental, donde permanecen entre varios meses y varios años antes de regresar al Pacífico occidental. La porción de los peces que migran al Pacífico oriental varía entre años, y ésto parece ser una causa importante de la variación anual en las capturas en el Océano Pacífico oriental. (PDF contains 94 pages.)