Jørgensen C, Lydersen C, Brix O, Kovacs K M
Norwegian Polar Institute, Polar Environmental Center, N-9296 Tromsø, Norway.
J Exp Biol. 2001 Nov;204(Pt 22):3993-4004. doi: 10.1242/jeb.204.22.3993.
This study investigated physiological and behavioural aspects of diving development in pups of the harbour seal Phoca vitulina. Behavioural data (4280 h, 6027 dives) from time/depth recorders (N=13) deployed on pups aged 0-19 days are presented concomitantly with physiological measurements (N=8, sampled both early and late in the nursing period) of blood oxygen stores and body composition. Pups grew from 12.6+/-1.8 kg (mean age 2 days, total body fat 16+/-4 %) to 22.2+/-2.5 kg (mean age 16 days, total body fat 35+/-5 %; means +/- S.D.) over the duration of the experiment. Pups less than 5 days of age had an elevated haematocrit and reduced plasma volume compared with older pups. Although plasma volume and blood volume increased, mass-specific blood oxygen stores (total haemoglobin) fell during the study period. Simultaneously, the following behavioural indicators of diving ability increased: the proportion of time spent in the water, dive depth, dive duration, bottom time and maximum daily swimming velocity. In addition, the proportion of dives that were identified by cluster analyses as being U-shaped increased significantly with age. On the basis of the measured blood oxygen stores, less than 1 % of the recorded dives exceeded the calculated aerobic dive limit. Thus, development in blood oxygen stores or rates of oxygen consumption did not seem to restrain the rate of neonatal dive development in harbour seals. It appears that behavioural modifications (experience and learning) may be the primary rate-limiting factors for ontogeny of diving skills in neonates of this species.
本研究调查了港海豹（Phoca vitulina）幼崽潜水发育的生理和行为方面。展示了部署在0至19日龄幼崽身上的时间/深度记录器的行为数据（4280小时，6027次潜水），同时还给出了血液氧储备和身体组成的生理测量数据（N = 8，在哺乳期早期和晚期均进行采样）。在实验期间，幼崽体重从12.6±1.8千克（平均年龄2天，全身脂肪16±4%）增长到22.2±2.5千克（平均年龄16天，全身脂肪35±5%；平均值±标准差）。与较大的幼崽相比，小于5日龄的幼崽血细胞比容升高，血浆量减少。尽管血浆量和血量增加，但在研究期间，质量特异性血液氧储备（总血红蛋白）下降。同时，以下潜水能力的行为指标增加：在水中花费的时间比例、潜水深度、潜水持续时间、水底停留时间和最大每日游泳速度。此外，通过聚类分析确定为U形的潜水比例随年龄显著增加。根据测得的血液氧储备，记录的潜水中不到1%超过了计算出的有氧潜水极限。因此，血液氧储备或氧消耗率的发育似乎并未限制港海豹幼崽新生儿期潜水发育的速度。看来行为改变（经验和学习）可能是该物种新生儿潜水技能个体发育的主要限速因素。
