科研之友
微信
新浪微博
Facebook
分享链接
摘要
Calanoid copepods from the genus Acartia are well studied because they are promising live feeds in marine larviculture. Several Acartia spp. are adapted to the occurrence of sudden unfavorable environmental conditions and can arrest their embryogenesis by entering quiescence. This trait can be used practically for establishing an egg bank, where embryos can be kept alive and hatched at a later time. The stored embryos can be shipped to end-users and the hatched nauplii used directly as live feed as well as they can be used to establish new copepod cultures. Acartia tonsa (Dana) is a cosmopolite and therefore an obvious candidate for being mass produced centrally at specific offsite installations, transferred and used worldwide. Moreover embryos from other species from this genus are shown in the present paper to have similar capacities in terms of survival in cold storage. To avoid the transfer of exogenous species in new environments, it is recommended to cultivate regional or even local species of copepods. In the present contribution we compare the cold storage capacity of embryos produced by seven strains of Acartia spp. isolated from different zoogeographical regions ranging from Northern Europe to the subtropical USA and tropical Asia. Our results showed that cold storage capacity of embryos is very dependent on egg size. The longest storage capacity, with egg hatching success >50% is demonstrated for embryos originating from temperate European waters and in particular from Adriatic Mediterranean and Baltic Sea waters (240 and 150 days, respectively) while the shortest storage capacities were found from species from sub-tropical Mexican Gulf, USA (10 days). Higher survival has a tendency to correlate with larger egg biovolume. However, we cannot exclude a possible and unknown unidirectional selection for embryo storage tolerance caused by the management practice in long term continuous cultures. We conclude that the studied embryos from the genus Acartia can all be stored for different time periods and hence are relevant for being used as regional/local egg banks and further studies for developing future live feed items. Statement of relevance: We consider calanoid copepod live feed products as a valuable supplement or alternative source for hatcheries. This is due to the fact that by introducing copepod nauplii as first feed items more fish species with small mouth gapes will be cultivated. Copepod organisms cannot be shipped due to the fact that they are fragile organisms. However, their embryos in a cold storage situation enter arrested development that lasts viable for months. We investigate seven strains of Acartia spp. embryos for their capabilities to be cold stored and conclude that all strains have that capability. This is considered promising for future mass production of calanoids for the benefit of the industry.
- 出版日期2016-4-20
