摘要
本文依据1989／1990和1990／1991两个南极夏季在普里兹湾以北海域所获的拖网样品，应用分布混合分析方法，研究大磷虾种群的年龄结构。结果表明，种群内最多可能包括6个年龄组：当年幼体，l＋，2＋，3＋，4+和5+龄虾。年龄组成的地区变化较大，特别是1+龄虾，有时很强，有时完全不存在；5+龄虾的比重很小，平均不到1%，在多数样品中分析不出来。在全部6734尾所分析的大磷虾（当年幼体0+不包括在内）中，1+龄占25．63%，2+龄占22．53%，3+龄占43．46%，4+龄占7．89%，5+龄占0．49%由于取样点都在外海，1+和2+龄虾的比例大大低于大磷虾种群实际应有的比例。在成体中3+龄虾占绝对优势（83．8％），反映生殖后的死亡率相当高。从各年龄组的平均体长可以发现，从未成体（1+）到次成体（2+）体长增长很快（14．22mm／a），而从次成体到成体（3+），生长主要是性腺发育，体长增长缓慢（5mm／a）。
Age-groups of krill (Euphausia superba Dana) collected from the Prydz Bayregion in austral summer of 1989/1990 and 1990/1991 were studied by means ofdistribution mixture analysis from length-frequency data. The results showed thatkrill population might consist of as many as six age-groups: O+,1+,2+,3+,4+ and 5+.Differences in age structure of samples collected at different stations were great,especially in the strengths of 1+ age-groups. Age group 5+ was very weak (small),no more than l % by average- Among the 6 734 specimens (larvae not included)analysed. 1+ accounted for 25.63%; 2+, 22.53%; 3+, 43.46 %; 4+, 7.89 % and 5+0.49 %. The proportions of 1+ and 2+ age-groups observed might be much lowerthan the real ones in the krill population, since all the samples used for the presentstudy were from the open area. That the 3+ was the dominant (87.3gh ) age-groupamong the adults indicated that mortality after spawning must be high. The incre-ases between the mean body lengths of successive age groups showed that high growthrate (14 mm/a) occured in the stage from 1+ juvenile to the 2+ subadult, and de-creased rapidly (5mm/a) during the stage from subadult to the adult (3+), owingto the growth of sexual products.'
出处
《海洋与湖沼》
CAS
CSCD
北大核心
1995年第6期598-605,共8页
Oceanologia Et Limnologia Sinica
基金
国家八五攻关专题!85-905-02-01号
