Sex Ratio of Calanoid Copepods in Relation To Population Composition in the Northwestern Mediterranean

Kouwenberg, J. H. M.

doi:10.1163/156854093x00649

Cited by 20 publications

(17 citation statements)

References 14 publications

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“…However, they differ distinctly in feeding habits and in size. The smaller species A. clausi, C. anglicus and P. parvus weighed 4.6 to 6.6 μg (dry mass) while the dry mass of T. longicornis Table 1 List of studied species: abbreviations, feeding preferences, distribution (Turner, 1984;Kouwenberg, 1993;Krause, 1995;Mauchline, 1998) (Table 3). Due to the small size of copepods the measurements of enzyme activities and storage products require optimised methods such as microscale extraction procedures, sensitive substrates, and optimum assay conditions.…”

Section: Resultsmentioning

confidence: 99%

Microassays for a set of enzymes in individual small marine copepods

Knotz

Boersma

Saborowski

2006

Comparative Biochemistry and Physiology Part A: Molecular &

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Fluorogenic assays for a set of five hydrolytic enzymes involved in digestion and food utilization (alanine and arginine aminopeptidase, lipase/ esterase, chitobiase, and beta-glucosidase) were optimized to measure activities of these enzymes in the same extracts of individual small North Sea copepods. The enzyme activities of Acartia clausi, Centropages typicus, Corycaeus anglicus, Paracalanus parvus, and Temora longicornis showed distinct species specific activity patterns, but also high intra-specific variability. Protein, lipids, carbon and nitrogen (C, N) were determined with micro-scale assays in individual copepods or in batches of 10 to 50 animals. Water soluble protein contents ranged from 16% to 38%, and lipid contents from 2.4% to 5.5% of dry mass. The molar C/N ratios were between 4.1 and 4.5. The presented microassays provide suitable tools for studying physiological reactions of copepods and other small pelagic crustaceans in response to variable environmental conditions.

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Section: Resultsmentioning

confidence: 99%

Microassays for a set of enzymes in individual small marine copepods

Knotz

Boersma

Saborowski

2006

Comparative Biochemistry and Physiology Part A: Molecular &

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“…In these populations, males are often numerous only at the beginning of the reproductive period, then become rare later. For many authors (Marshall 1949;Chapman 1969;Corkett & McLaren 1978;Hopkins 1982;Tande & GrÖnvik 1983;Bayly 1986), the short life span of males explains, at least in part, the relative abundance of females to males, observed in calanoids, such as in Calanus helgolandicus (Green et al 1993;Kouwenberg 1993), Pseudocalanus elongatus (Digby 1950;Green et al 1993), Pseudocalanus minutus (Marshall 1949) and Clausocalanus spp. (Kouwenberg 1993).…”

Section: Discussionmentioning

confidence: 99%

Female genital structures in several families of Centropagoidea (Copepoda: Calanoida)

Cuoc¹,

Defaye

Brunet³

et al. 1998

Phil. Trans. R. Soc. Lond. B

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The female genital structures of 21 calanoid species belonging to the families Candaciidae, Centropagidae, Pontellidae, Sulcanidae, Temoridae and Tortanidae were studied using light and electron microscopy (scanning electron microscopy, transmission electron microscopy). Except the monotypic Sulcanidae, their organization conforms to a common pattern characterized by egg-laying ducts opening through paired adjacent gonopores into a small cavity, the genital atrium, covered by a genital operculum and opening to the outside through a distal atrial slit. No seminal receptacle is present and the seminal products must be stored for a brief period in the genital atrium.The genital structures occupy a well delimited genital area, the main changes in which concern their position on the ventral face of the genital double-somite, and operculum morphology. Their organization and possible mode of operation are compared with those of other calanoid families. A possible correlation between absence of seminal receptacles and mating behaviour is discussed.

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“…It appears that during maturation young life stages are carried back south with surface currents. Probably, the life cycle is passed through several times -up to 3 times in temperate waters (Conover, 1988); 5-6 times in the Mediterranean during summer (Kouwenberg, 1993), until the southern distributional boundary of this species is reached and the annual cycle completed with the onset of winter conditions, when CV sinks into deeper layers.…”

Section: Discussionmentioning

confidence: 99%

“…The sex ratio for calanid copepods was often suggested to be in favour of females (Green et al, 1993;Kouwenberg, 1993). This seems to be partly due to the sampled depth range, and the geographical region and the season of the surveys.…”

Section: Cross-slope Transect -Neuston Haulsmentioning

confidence: 99%

“…Thus, we assume that both species have developed different reproductive strategies. It is generally assumed that males of calanid copepods moult earlier than females in order to use any opportunity to fertilize newly moulted females, thus maximizing their reproductive success (Kouwenberg, 1993). While C. carinatus seems to follow this strategy, males of C. helgolandicus do not appear to be as short-lived as has often been suggested.…”

Section: Cross-slope Transect -Neuston Haulsmentioning

confidence: 99%

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Population structure and reproduction ofCalanus helgolandicus (Copepoda, Calanoida) along the iberian and Moroccan slope

Stöhr

Schulz

John

1996

Helgolander Meeresunters

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off the Iberian Peninsula and Morocco, the abundant calanoid copepod Calanus helgolandicus (Claus) was collected from a depth of 1000 m to the surface. Differences in depth preference were correlated with the life stage and geographically differing vertical salinity structures. In autumn and winter, only stage V copepodids (CV) and adults were found, in spring also younger copepodid stages. Within the range of the Mediterranean outflow water (MOW), a sharp decline of abundances of all stages was evident during all cruises. In autumn 1991, the bulk of the population was recorded south of the MOW; in winter 1992 north of it. During winter, numbers had declined by 70 %, supporting the idea that winter individuals represent the same generation as was encountered in autumn, and that they had been transported northwards. CV stages preferred the depth layer 400-800 m, in autumn and winter. Adults were found in autumn at the same depth south of the MOW, while they preferred the 0-400 m layers north of it. In winter, the abundance of adults increased, males preferred the 400-600 m depth layer, while females stayed at 200-400 m. In spring 1991, stages younger than CV were found in high densities, all stages concentrating in the upper 200 m. During the crossslope survey in spring off Portugal, an absolute abundance maximum of females was found. In contrast, offshore densities were very low. On the basis of these findings, the hypothesis of a Mediterranean centre of distribution and dispersal into the Atlantic is questioned. It is suggested that a separate, reproductively active population of C. helgolandicus exists off NW. Africa.

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Sex Ratio of Calanoid Copepods in Relation To Population Composition in the Northwestern Mediterranean

Cited by 20 publications

References 14 publications

Microassays for a set of enzymes in individual small marine copepods

Microassays for a set of enzymes in individual small marine copepods

Female genital structures in several families of Centropagoidea (Copepoda: Calanoida)

Population structure and reproduction ofCalanus helgolandicus (Copepoda, Calanoida) along the iberian and Moroccan slope

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