乌苏里江大麻哈鱼（♀）婚姻色差异的生态指征意义

黑龙江大麻哈鱼（Oncorhynchus keta）繁殖群体由鄂霍次克海经俄罗斯境内的黑龙江干流洄游至我国境内即分成黑龙江和乌苏里江两个地理群体。过去大麻哈鱼洄游至我国时婚姻色均较浓艳，但近十年来发现洄游至乌苏里江的大麻哈鱼部分个体婚姻色浓艳，部分婚姻色很浅或无色。为了揭示婚姻色浓淡差异的原因及其对大麻哈鱼繁殖适应性的指征作用，笔者于2011年9月20～29日，对乌苏里江大麻哈鱼回归繁殖群体进行了调查，共采集样品94尾，将其划分为婚姻色浓艳个体组（红色度a＋值〉13）和浅淡个体组（红色度a赤〈7），进行了两群组间的繁殖生态学参数比较分析。结果表明，浅淡个体的成熟系数（CSI）、卵径、卵重、年龄、体长和体质量均小于浓艳个体，且差异极显著（P〈0．01）；婚姻色浅淡个体的绝对繁殖力显著小于浓艳个体（P〈0．05）；但二者的肥满度指数差异不显著。两群组间各繁殖生态参数间相关关系的差异分析表明，婚姻色浅淡个体性腺发育落后于浓艳个体，表明婚姻色浅淡个体的繁殖适合度低于婚姻色浓艳个体。

Ecological Implication of Nuptial Colors in Chum Salmon (Oncorhynchus keta ) in Chinese Ussuri River

Chum salmon （Oncorhynchus keta） breeding population in Amur River immigrated from Okhotsk Sea in Russia runs into two geographic populations Amur population and Ussuri population when the salmon reach China border. In the past decade, China A- mur population developed strong nuptial colors very well, but few Ussuri population showed strong nuptial colors, even did not when they entered China. There were two groups faint color females （red chrominance a＊〉13 ） and strong color females （red chrominance a＊〈7）in Ussuri females whose breeding parameters were analyzed during 20th~29th of September in 2011 to evaluate the implica- tions of nuptial colors differentiation within a population in Ussuri River. It was found that the age, gonado-somatic index （GSI）, egg diameter and weight, body length and body weight of the faint color females were all smaller than the strong color females very signifi- cantly （P〈0.01）. The faint color females were found to have less absolute fecundity than the strong color females did significantly （P〈0.05）, without significant differences in condition factor between the two groups. Correlations among reproductive parameters between the two groups revealed that the faint color females had lagged gonad development behind the strong color females, indicating that the strong color females shared higher reproductive fitness than the faint color females.