Fish Communities in Lake Tanganyika, Their Ecology and Evolution

我们在过去十年的实地研究表明，在坦噶尼喀湖的沿海鱼类群落中，合作性种间关系和竞争性种间关系高度融合。鱼类群落的巨大多样性归因于该湖泊中慈鲷的爆炸性适应。我们对该鱼群的等位酶电泳系统发育研究表明，至少有7个古老的祖先谱系形成了目前的慈鲷动物群，该湖可以被认为是东非主要慈鲷谱系的进化水库。那个湖的物种组成在地理上各不相同。1988年和1989年在赞比亚的穆普伦古首次调查了南部地区的鱼类区系，并与以前调查过的中部（坦桑尼亚的马哈尔）和北部（扎伊尔的卢汉加和奔巴）地区进行了比较。南部地区的物种数量比中部和北部地区多出10种，约为中部和北部地区的1 / 4。在三个区域中，有相关但不同的物种占据了一些等效的生态位。在一群使用贝壳产卵的慈鲷中，大多数是南方地区特有的，在它们的繁殖过程中发现了宿主-寄生虫关系。在某些鱼食性或鳞食性鱼类种群中，体色和颚侧度存在多态性。这种多态性与狩猎策略密切相关。每一种变体的觅食效率都可以提高，因为它们很难防御有专门狩猎策略的掠食者。这种种内“合作”和同一行会物种之间的种间合作表明，相互依存关系是群落组织各个层面的重要因素。本文还研究了同居近缘种间生境利用的灵活性。当几个种类的食藻动物被从一个区域移除时，相同的物种会重新占据相同的位置。同样，在对12种蓝藻进行为期一年的连续去除实验中，相同的繁殖地被相同的物种重新占据。这些结果表明，对于微生境的利用，每个物种都有一个狭窄的适应带，并且微生境在物种之间通常是不可交换的。少

Our field studies in the last decade have documented that cooperative interspecific relationships as well as competitive ones are highly incorporated in coastal fish communities in Lake Tanganyika. The great diversity of the fish community is attributed to the explosive adaptation of cichlids in this lake. Our phylogenetic study of this fish group by allozyme electrophoresis indicated that at least seven old, ancestral lineages contributed to present cichlid fauna and this lake can be recognized as an evolutionary reservoir of major lineages of cichlids in East Africa.The species composition varies geographically within that lake. Fish fauna of the southern region was investigated for the first time at Mupulungu, Zambia in 1988 and 1989 and compared with that of the central (Mahale, Tanzania) and northern (Luhanga and Pemba, Zaire) regions surveyed before. The species number was greater in the southern region by 10 species than in the central and northern regions and a quarter of the s … More pecies were endemic to the southern region. Some equivalent niches were occupied by related but different species among the three regions. In a group of cichlids using shells for spawning, most of which are endemic to the southern region, a host-parasite relationship was recognized during their reproduction.Polymorphism in body color and jaw laterality within a population was found in some piscivorous or lepidophagous species. This polymorphism was closely linked to hunting tactics. The foraging efficiency of each morph can increase because of the difficulty of defense for a prey against predators each having specialized hunting tactics. This intraspecific "cooperation" and the interspecific cooperation between species in the same guild, found in our previous study, indicate that interdependent relationships are important elements on various levels of the community organization.The flexibility in the habitat utilization among cohabiting related species was also studied. When several species of algal eaters were removed from an area, the same species re-occupied the same sites. Similarly, in successive removal experiments of brooding pairs in 12 lamprologini species for one year, the same breeding sites were re-occupied by the same species. These results suggest that for the use of microhabitat each species has a narrowly tuned adaptive zone and microhabitats are usually not exchangeable between species. Less