Studies on the biology of limpets: II. The breeding of Patella vulgata L. in Britain

Abstract

Some preliminary observations in North Cornwall (Orton, 1946) showed that the periods of breeding of the three British species of limpets were different. In order to determine these differences more accurately, and to study the breeding cycle, samples oflimpets from six localities in Britain were examined at regular intervals for 5 years. This paper gives the results obtained for the common limpet Patella vulgata, which was present at all the localities sampled and was the most intensively studied of the three species. Later papers will deal with the remaining species and with other aspects of the investigations.The work fell rougWy into two stages. For.the first season, 1945-46, it was necessary to determine exactly the distribution of sexes in the various sizegroups at the different stations, since it was known that at Plymouth the small sizes were preponderantly male (Orton, 1920(Orton, , 1928 and rougWy equal numl?ers of both sexes are desirable for regular observations on breeding. At the same time the opportunity was taken to re-investigate sex-phenomena which had been noted previously and thought to indicate a change of sex during the life-history (Orton, 1920(Orton, , 1928. For the remaining period of study emphasis was placed on determining the exact period of spawning in the various localities, and on possible spawning stimuli.Although J. H. O. collected most of the samples that were taken personally, as distinct from those collected by other professional or amateur collectors, all three authors have taken part in the field work. J. H. O. was mainlyresponsible for the examination of the gonad stages, their grouping, and the calculation of the various numerical factors, J. M. D. carried out the histologicalwork and described the arbitrary stages, whilst A. J. S. analysed the breeding cycle and explored the relationship between meteorological factors and spawning. This paper has been prepared by A. J. S. and J. M. D., who are responsible for all opinions expressed herein.

The reproductive cycle ofPatella candei gomesiiDrouët, 1858 (Mollusca: Patellogastropoda), an Azorean endemic subspecies

“…In the literature, temperature has been linked to the reproductive cycles of Patella species (Orton et al, 1956;Fretter and Graham, 1976). Species with planktotrophic larvae spawn just prior to the time when plankton is maximal (ensuring food for the larvae) at a time of rising or high sea surface temperatures (Branch, 1981).…”

“…Spawning may also be triggered by sea roughness (Orton et al, 1956;Fretter and Graham, 1976;Bowman and Lewis, 1977;Bowman and Lewis, 1986). In the Azores, sea roughness is higher in winter, arguing in favour of the extended period of spawning.…”

“…Several studies have been undertaken concerning the reproductive cycles of Patella species (Orton et al, 1956;Orton and Southward, 1961;Blackmore, 1969;Lewis and Bowman, 1975;Bowman and Lewis, 1986). Most are based on the macroscopic index described by Orton et al (1956).…”

“…Most are based on the macroscopic index described by Orton et al (1956). The present work reports on a preliminary investigation of the reproductive seasonality of the two ecological morphotypes of P. candei gomesii in São Miguel (Azores).…”

Reproduction in the intertidal limpetCellana ornatain southern New Zealand

“…Their reproductive cycles vary, with some having extended breeding seasons with multiple spawnings (e.g., Cellana radiata (Balaparameswara Rao 1973); Cellana radians (Creese & Ballantine 1983)) and others having restricted spawning periods per year, with long resting stages in between (e.g., Patella vulgata (Orton et. al.…”