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THE INTERACTION BETWEEN BREEDING AND GROWTH RATE IN THE BARNACLE ELMINIUS MODESTUS DARWIN
Author(s) -
Crisp D. J.,
Patel Bhupendra
Publication year - 1961
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1961.6.2.0105
Subject(s) - biology , barnacle , hermaphrodite , slow growth , breed , growth rate , zoology , anatomy , ecology , crustacean , geometry , mathematics , economics , macroeconomics
Elminius modestus Darwin is shown to be a slightly protandrous hermaphrodite in which the testes, vesiculae seminales and penes develop in specimens measuring between 3 and 5 mm, and the ovaries in specimens measuring from 4 to 6 mm. Fast growing specimens mature and bear embryos within 6 to 7 weeks of settlement, but crowding may slow down growth and delay the maturation of the ovary considerably. Very slow growing specimens may eventually become mature at an abnormally small size. When individuals were prevented from breeding by isolation but were grown otherwise under identical conditions, they grew significantly faster and to a larger size than individuals which were able to cross‐fertilize and breed. The valves of the shell showed less difference in growth rate than any other structure. The slower growth of breeding individuals was caused not by competition due to their closer proximity, but by loss of tissue as egg masses. The mean difference in tissue weight, excluding shell, was about equal to the calculated loss of tissue in the form of eggs. Details are given of wet and dry weights and of the weights of the individual shell compartments of this species.