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You searched for: Journal name Helgoland marine research Remove constraint Journal name: Helgoland marine research Subject term gonads Remove constraint Subject term: gonads
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1. Cuttlebone morphometrics and sex identification of Sepia bertheloti (d’Orbigny, 1835) from the central-east Atlantic

Author:
Airam Guerra-Marrero; David Jiménez-Alvarado; Vicente Hernández-García; Leticia Curbelo-Muñoz; José Juan Castro-Hernández
Source:
Helgoland marine research 2019 v.73 no.1 pp. 10
ISSN:
1438-387X
Subject:
Sepia; females; gonads; males; morphometry; oocytes; Africa
Abstract:
... Analysis of 322 cuttlebones of Sepia bertheloti caught in the waters of the Northwest Africa showed significant differences in growth between males and females. Morphometric analysis revealed a relatively different cuttlebone growth pattern between sexes, with males presenting faster growth in length to reach larger sizes and females displaying greater growth in width. This difference in cuttlebon ...
DOI:
10.1186/s10152-019-0531-0

2. Growth and reproduction of the north-eastern Atlantic keystone species Patella aspera (Mollusca: Patellogastropoda)

Author:
Ricardo Sousa; João Delgado; Ana Rita Pinto; Paulo Henriques
Source:
Helgoland marine research 2017 v.71 no.1 pp. 8
ISSN:
1438-387X
Subject:
Patella aspera; allometry; females; gametogenesis; gonads; keystone species; limpets; males; monitoring; mortality; population dynamics; sexual maturity; spawning; winter
Abstract:
... The growth and reproductive biology of the limpet Patella aspera were studied in the north-eastern Atlantic, Madeira archipelago, to enhance the knowledge concerning biological parameters and population dynamics of this species. This study comprised the estimation of growth rates, sexual maturity, reproduction, recruitment patterns, mortality coefficients and the exploitation rate, and yield-per-r ...
DOI:
10.1186/s10152-017-0488-9

3. Maturation at a young age and small size of European smelt (Osmerus eperlanus): A consequence of population overexploitation or climate change?

Author:
Timo Arula; Heli Shpilev; Tiit Raid; Markus Vetemaa; Anu Albert
Source:
Helgoland marine research 2017 v.71 no.1 pp. 7
ISSN:
1438-387X
Subject:
Osmerus eperlanus; climate change; climatic factors; condition factor; fish; fisheries; gonads; population dynamics; reproduction; sexual maturity; Baltic Sea
Abstract:
... Age of fish at maturation depends on the species and environmental factors but, in general, investment in growth is prioritized until the first sexual maturity, after which a considerable and increasing proportion of resources are used for reproduction. The present study summarizes for the first the key elements of the maturation of European smelt (Osmerus eperlanus) young of the year (YoY) in the ...
DOI:
10.1186/s10152-017-0487-x

4. Relative growth and reproductive cycle of the date mussel Lithophaga lithophaga (Linnaeus, 1758) sampled from the Bizerte Bay (Northern Tunisia)

Author:
Ferdaous Jaafar Kefi; Samir Boubaker; Najoua Trigui El Menif
Source:
Helgoland marine research 2014 v.68 no.3 pp. 439-450
ISSN:
1438-387X
Subject:
allometry; females; gonadosomatic index; gonads; hermaphroditism; males; mussels; salinity; seawater; sex ratio; spawning; water temperature; winter; Tunisia
Abstract:
... Relative growth and the reproductive cycle of the date mussel Lithophaga lithophaga were studied from September 2002 to October 2003 in the Bizerte Bay (Northern Tunisia). Relationships between shell length and shell width, shell height as well as volume-related variables (shell dry weight, soft tissues dry weight and total wet weight) showed negative allometries in both sexes except for shell wid ...
DOI:
10.1007/s10152-014-0400-9

5. Life history of Lineus viridis (Müller, 1774) (Heteronemertea, Nemertea)

Author:
Jörn von Döhren; Patrick Beckers; Thomas Bartolomaeus
Source:
Helgoland marine research 2012 v.66 no.3 pp. 243-252
ISSN:
1438-387X
Subject:
animals; autumn; dimorphism; eggs; females; gonads; hermaphroditism; life history; males; mating behavior; oogenesis; sand; sperm competition; spermiogenesis; spring; surveys; North Sea
Abstract:
... Lineus viridis is a common nemertean species of North-Atlantic intertidal sand flats. Its mating behaviour is peculiar insofar as this species is reported to be polyandric. However, detailed information on this topic is lacking. In order to get more data on the reproduction, oogenesis and life history of this species, a population in the Wadden Sea on the Isle of Sylt (North Sea) was studied betwe ...
DOI:
10.1007/s10152-011-0266-z

6. Gonad morphology, oocyte development and spawning cycle of the calanoid copepod Acartia clausi

Author:
Sonja M. Eisfeld; Barbara Niehoff
Source:
Helgoland marine research 2007 v.61 no.3 pp. 193-201
ISSN:
1438-387X
Subject:
Acartia; abdomen; clutch size; developmental stages; egg production; eggs; females; gonads; head; histology; oocytes; oogenesis; oogonia; reproductive traits; spawning; North Sea
Abstract:
... Information on gonad morphology and its relation to basic reproductive parameters such as clutch size and spawning frequency is lacking for Acartia clausi, a dominant calanoid copepod of the North Sea. To fill this gap, females of this species were sampled at Helgoland Roads from mid March to late May 2001. Gonad structure and oogenesis were studied using a combination of histology and whole-body- ...
DOI:
10.1007/s10152-007-0066-7

7. Carbonic anhydrase activity and biomineralization process in embryos, larvae and adult blue mussels Mytilus edulis L.

Author:
D. Medaković
Source:
Helgoland marine research 2000 v.54 no.1 pp. 1-6
ISSN:
1438-387X
Subject:
Mytilus edulis; X-ray diffraction; adults; aragonite; biomineralization; calcification; calcite; carbonate dehydratase; crystals; enzyme activity; gonads; larvae; mussels; quartz; shell gland
Abstract:
... To decide whether a physiological role can be attributed to enzymatic activity with respect to crystal formation and biomineralization of the first larval shell, carbonic anhydrase (CA) activity was measured in embryos and larvae of the blue mussels Mytilus edulis L. Also, CA activity was determined in the mantle edge and gonads of adult mussels with different shell length and condition index. The ...
DOI:
10.1007/s101520050030