Life cycle and production of Assiminea japonica V. Martens and Angustassiminea castanea (Westerlund) at a reed marsh in Gamo lagoon, northern Japan (Gastropoda: Assimineidae)
Kurata, K.; Kikuchi, E. (1999). Life cycle and production of Assiminea japonica V. Martens and Angustassiminea castanea (Westerlund) at a reed marsh in Gamo lagoon, northern Japan (Gastropoda: Assimineidae). Ophelia 50(3): 191-214. https://dx.doi.org/10.1080/00785326.1999.10409395
In: Ophelia: International Journal of Marine Biology. Ophelia Publications: Helsingør. ISSN 0078-5326, more
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| Keywords |
Marine/Coastal; Brackish water |
| Abstract |
Population structures, life cycles, growth patterns, and secondary productions of two assimineids, Assiminea japonica and Angustassiminea castanea, were studied at Gamo salt marsh, northern Japan. Cohort analysis revealed a large variation in annual recruitment. It was also revealed that one cohort which had been recruited in a certain year occupied a large proportion of the whole population. Recruitment of A. japonica occurred from August to September whereas that of A. Castanea occurred from September to October. For A. japonica, individuals 1.5 years after recruitment seem to be mature and reproductive, and for A. castanea, individuals at least 1.7 years after recruitment seem to be mature and reproductive. It was estimated that A. japonica had a field longevity of 32–36 months and A. castanea could live for 55 months. Mean annual production of A. japonica (2.73 g AFDW·m-2·yr.-1) during two years was larger than that of A. castanea (0.42 g AFDW·m-2·yr.-1). Secondary production and P/B varied largely between years for both species in relation to the age of the predominant cohorts. P/B of A. japonica at the age of 9–20 mos. was 1.26 whereas that at the age of 21–32 mos. was 0.28. P/B of A. castanea at the age of 20–31 mos. was 0.64 and that at the age of 32–13 mos. was 0.32. |
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