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  • 1
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    Recruitment season, size, and age of young American eels (Anguilla rostrata) entering an estuary near Beaufort, North Carolina (2021)
    In:  http://aquaticcommons.org/id/eprint/15211 | 403 | 2014-05-30 07:35:29 | 15211 | United States National Marine Fisheries Service
    Details
    Publication Date: 2021-07-04
    Description: Net catches from 1985–86 to 1994–95 at Pivers Island, North Carolina, indicated that glass-eel stage American eels (Anguilla rostrata) were recruited to the estuary from November to early May, with peak numbers in January, February, and March. There was no declining trend in recruitment over the years of sampling. Except for one year, there was no clear seasonal decrease in mean length. But shorter glass eels were older than longer glass eels, as judged by age within the glass eel growth zone of the otolith, suggesting that smaller fish took longer to arrive. The mean age of glass eels collected from the lower estuary and a freshwater site 9.5 km upriver differed by 8.4 d (36.2 vs. 44.6, respectively). Outer increments (30–35) of the otolith growth zone of glass eels from North Carolina were significantly wider than corresponding increments of otoliths from New Brunswick. Mean total ages of North Carolina, New Jersey, and New Brunswick elvers were 175.4, 201.2, and 209.3 d, corresponding to mean lengths of 55.9, 60.9, and 58.1 mm TL, respectively. The mean durations of glass-eel growth zones (44.6, 62.3, and 69.8) were in close agreement with those from previous studies, but total ages were not. This suggested that perhaps some finer (leptocephalus stage) increments were not detected by light microscopy, differences occurred in seasonal increment deposition, or absorption of the otolith material may have taken place during metamorphosis, rendering the aging of larvae inaccurate. Judging from the long recruitment period and seasonal uniformity in both mean age and length found in our study, the spawning period of American eels may be somewhat more protracted than previously considered.
    Keywords: Biology ; Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 299-306
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  • 2
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    Recruitment of larval Atlantic menhaden (Brevoortia tyrannus) to North Carolina and New Jersey estuaries: evidence for larval transport northward along the east coast of the United States (2021)
    In:  http://aquaticcommons.org/id/eprint/15235 | 403 | 2014-06-01 18:54:42 | 15235 | United States National Marine Fisheries Service
    Details
    Publication Date: 2021-07-05
    Description: Age, size, abundance, and birthdate distributions were compared for larval Atlantic menhaden (Brevoortia tyrannus) collected weekly during their estuarine recruitment seasons in 1989–90, 1990–91, and 1992–93 in lower estuaries near Beaufort, North Carolina, and Tuckerton, New Jersey, to determine the source of these larvae. Larval recruitment in New Jersey extended for 9 months beginning in October but was discontinuous and was punctuated by periods of no catch that were associated with low water temperatures. In North Carolina, recruitment was continuous for 5–6 months beginning in November. Total yearly larval density in North Carolina was higher (15–39×) than in New Jersey for each of the 3 years. Larvae collected in North Carolina generally grew faster than larvae collected in New Jersey and were, on average, older and larger. Birthdate distributions (back-calculated from sagittal otolith ages) overlapped between sites and included many larvae that were spawned in winter. Early spawned (through October) larvae caught in the New Jersey estuary were probably spawned off New Jersey. Larvae spawned later (November–April) and collected in the same estuary were probably from south of Cape Hatteras because only there are winter water temperatures warm enough (≥16°C) to allow spawning and larval development. The percentage contribution of these late-spawned larvae from south of Cape Hatteras were an important, but variable fraction (10% in 1992–93 to 87% in 1989–90) of the total number of larvae recruited to this New Jersey estuary. Thus, this study provides evidence that some B. tyrannus spawned south of Cape Hatteras may reach New Jersey estuarine nurseries.
    Keywords: Biology ; Ecology ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 609-623
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and Rearrangement of 7-Halobicyclo[3.2.0]hept-2-en-6-ols (1977)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 1528-1544 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthese und Umlagerung von 7-Halo-bicyclo[3.2.0]hept-2-en-6-olenDie Reaktion von verschiedenen 7-halogen-substituierten Bicyclo[3.2.0]hept-2-en-6-onen mit komplexen Metallhydriden oder mit Methylmagnesiumiodid zu den entsprechenden 7-Halo-bicyclo[3.2.0]hept-2-en-6-olen verläuft unter Angriff des Nucleophils trans zum Halogen, um dem vicinalen Kohlenstoff-Halogen-Dipol auszuweichen. In Gegenwart von starken Basen unterliegen die Halohydrine einer Umlagerung, die je nach der durch die intramolekularen Wechselwirkungen bedingten Konformation, entweder unter Hydridverschiebung zu Bicyclo[3.2.0]hept-2-en-6-onen oder, unter Ringverengung, zu Bicyclo[3.1.0]hex-2-en-6-carbaldehyden führt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19770600510
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  • 4
    Electronic Resource
    Electronic Resource
    Unexpected Configurational and Conformational Preference in Bicyclo [3.2.0]heptane Systems (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 703-720 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Einige 7endo-monosubstituierte Bicyclo[3.2.0]hept-2-en-6-one and Bicyclo-[3.2.0]heptan-6-one zeigen eine unerwartete thermodynamische Stabilität gegenüber den entsprechenden 7exo-Isomeren. Die basenkatalysierte Epimerisierung (NaOH oder N(CH2CH3)3) verschiedener 7-monosubstituierter Bicyclo[3.2.0]-hept-2-en-6-one (1-7) und Bicyclo[3.2.0]heptan-6-one (8-10) führt je nach Substituent (R) zu folgenden endo/exo-Gleichgewichtsgemischen: (a) Bicyclo[3.2.0]-hept-2-en-6-one: R = F: 89/11, R = C1: 87/13, R = CH3: 76/24, R = CH2CH3: 65/35, R = CH (CH3)2: 57/43, R= C (CH3)3: 10/90, R= C6H5: 66/34; (b) Bicyclo[3.2.0]-heptan-6-one: R = C1: 85/15, R = CH3: 45/55, R= C (CH3)3: 0,4/99,6. In jedem Fall wurde das gleiche Epimerengemisch erhalten, ausgehend sowohl vom endo- wie auch vom exo-Isomeren.Die bemerkenswerte endo-Stabilität wird einer Bevorzugung der Konformation 11 des Cyclobutanonringes zugeschrieben, verursacht durch geringere Pitzer-Spannung. So kann ein endo-Substituent an C(7) eine pseudoäquatoriale Lage am Cyclobutanonring einnehmen. Bei sehr sperrigen Substituenten mit zunehmender Raumerfüllung nimmt eine 1,2-abstossende Wechselwirkung langsam überhand, bis im Falle des t-Butylsubstituenten die exo-Konfiguration die stabilere wird.Die Dehalogenierung von 7-Halo-substituierten Bicyclo [3.2.0]hept-2-en-6-onen (15 bis 21) mit Zink und Eisessig und mit Tributylzinnhydrid führte zu den folgenden endo/exo-Epimerengemischen der entsprechenden 7-monosubstituierten Bicyclo [3.2.0]hept-2-en-6-one (2 bis 7): R = C1: 92/8, R = CH3: 93/7, R = CH2CH3: 93/7, R = CH(CH3)2: 92/8, R = C(CH3)3: 93/7, R = C6H5: 93/7. In allen Fällen, also unabhängig vom Substituenten R, war das endo-isomere stark bevorzugt. Es muss sich also um eine kinetische Kontrolle im isomerenbestimmenden Schritt handeln: Die Reduktion verläft über das Enolat, bzw. über eine Radikalspezies mit trigonal-planarer Anordnung am C(7), so dass die (irreversible) Wasserstoff-Anlagerung von der weniger behinderten Site, der exo-Seite her erfolgt.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650308
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  • 5
    Electronic Resource
    Electronic Resource
    Development of the enzyme-catalysed Baeyer-Villiger reaction as a useful technique in organic synthesis (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 334-337 
    Details
    ISSN: 0899-0042
    Keywords: lactone synthesis ; stereoselective oxidation ; monooxygenases ; Pseudomonas putida NCIMB 10007 ; Acinetobacter calcoaceticus NCIMB 9871 ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The current practices of using monooxygenase enzymes to perform regio- and stereoselective oxidation reactions in organic syntheses are reviewed. The isolation of a monooxygenase from Pseudomonas putida NCIMB 10007 and its use in the conversion of bicyclo[3.2.0]hept-2-en-6-one into two isomeric optically active lactones is described. The monooxygenase utilises NADH as cofactor and NADH-recycling is accomplished using formate and formate dehydrogenase. As alternative methodology, it is shown that a secondary alcohol can be converted into a chiral lactone using a dehydrogenase and a monooxygenase working in tandem with in situ cofactor recycling. © 1993 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050510
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