dos Santos José Enemir, Sales Naiara Guimarães, dos Santos Marcella Lourenço, Arantes Fábio Pereira, Godinho Hugo Pereira
Rev Biol Trop. 2016 Jun;64(2):537-45. doi: 10.15517/rbt.v64i2.19052.
Early development of fish larvae is a highly dynamic process and its study may provide important information about ontogenetic development, bioenergetic growth, behaviour, taxonomic characteristics for identification in natural environments, identification of spawning areas, and population monitoring. With the aim to provide knowledge about their growth and behaviour, to support larval rearing, and also taxonomic purposes, we studied the life history of the Prochilodus argenteus and P. costatus from hatching until the complete absorption of the yolk. Larvae were obtained through artificial reproduction at the Hydrobiology and Aquaculture Station of Três Marias, Minas Gerais, Brazil. Immediately after hatching, 100 larvae of each species were put in two plastic incubators for conditioning. On a daily basis, larvae behavior was recorded and 14 larvae of each species were collected to analyse body morphology. On the first day after hatching, larvae of P. costatus and P. argenteus showed an elongated and transparent body; the yolk sac was filled with individualized yolk globules. In both species, the embryonic fin rounded the caudal region of the body, the retina was non-pigmented and the gut was obliterated. At the second day post-hatching, larvae of both species dendritic chromatophores had emerged, the mouth was obliterated and the pectoral fin was observed. The larvae showed 38-43 myomeres in P. costatus and 42-43 in P. argenteus. For both species, the gas bladder was inflated and the lumen of the gut was already open. On the third day post-hatching, the mouth of P. costatus and P. argenteus was already open in a sub-terminal position; the retina was pigmented; the gill arches had lamellar protrusions and were partially covered by the operculum. On the fourth day post-hatching, the pigmentation pattern was maintained with greater intensity; the mouth occupied a terminal position, the yolk sac was almost completely reabsorbed, and the pectoral and caudal fins showed mesenchymal rays in both species. The gut showed a broad lumen with folded mucosa and epithelium with striated border. The larvae of both species showed similar swimming behaviour. Our study provided understanding about the morphophysiological aspects, species identification, larval development and growth, and the ontogenic characteristics of two Neotropical fishes with importance for commercial and sports fishing.
鱼类幼体的早期发育是一个高度动态的过程，对其研究可为个体发育、生物能量生长、行为、自然环境中分类鉴定的分类特征、产卵区识别以及种群监测提供重要信息。为了了解它们的生长和行为，支持幼体培育，并用于分类目的，我们研究了银锯脂鲤和科氏锯脂鲤从孵化到卵黄完全吸收的生活史。幼体通过巴西米纳斯吉拉斯州特雷玛丽亚斯水生生物学和水产养殖站的人工繁殖获得。孵化后，立即将每个物种的100尾幼体放入两个塑料培养箱中进行培育。每天记录幼体行为，并收集每个物种的14尾幼体进行身体形态分析。孵化后的第一天，科氏锯脂鲤和银锯脂鲤的幼体身体细长且透明；卵黄囊充满了单个的卵黄球。在这两个物种中，胚胎鳍环绕着身体的尾部区域，视网膜无色素，肠道闭塞。孵化后第二天，两个物种的幼体都出现了树枝状色素细胞，口闭塞，观察到胸鳍。科氏锯脂鲤的幼体有38 - 43个肌节，银锯脂鲤有42 - 43个。对于这两个物种，鳔充气，肠道腔已经开放。孵化后第三天，科氏锯脂鲤和银锯脂鲤的口已在亚末端位置张开；视网膜有色素；鳃弓有片状突起，部分被鳃盖覆盖。孵化后第四天，色素沉着模式更加明显；口占据末端位置，卵黄囊几乎完全被吸收，两个物种的胸鳍和尾鳍都显示出间充质鳍条。肠道显示出宽阔的腔，黏膜折叠，上皮有纹状缘。这两个物种的幼体表现出相似的游泳行为。我们的研究提供了对两种新热带鱼类形态生理方面、物种鉴定、幼体发育和生长以及个体发育特征的理解，这对商业和休闲捕鱼具有重要意义。
