Weight-Length and Length-Length Relationships of the Endangered Zebra Pleco Hypancistrus zebra (Siluriformes, Loricariidae) from the Xingu River, Amazon, Brazil
Fábio J. T. Barros, E. L. C. Rodrigues, Mayllon C. de S. Moura, R. Torres, Eris A. Paula, L. Sousa
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引用次数: 0
Abstract
Hypancistrus zebra is a Loricariid endemic to a very limited stretch of the Xingu River and has a high value in the ornamental fish trade. The natural populations have experienced high fishing pressure since the late 80s and were recently impacted by the construction of the third largest hydroelectric dam complex in the world, the Belo Monte Project. Since 2004, it has been considered critically endangered and had its capture and trade forbidden. Even with its capture and trade prohibited since 2004, the species continues to be one of the most trafficked fish in the world. The biometric knowledge of the species is essential for monitoring its natural populations and management in ex situ environments. This work aims to establish the weight-length relationship (WLR) and length-length relationship (LLR) of the species and to evaluate the condition factor (K) of H. zebra rescued from trafficking. The study was conducted at the Laboratório de Aquicultura de Peixes Ornamentais do Xingu from February 2022 to June 2022, estimating the parameters of WLR and LLR of 1165 specimens divided into four simple linear regression (SLR) models: all specimens, only juveniles, only females, and only males. The K of 190 specimens rescued from trafficking by the Brazilian Federal Police was evaluated. The WLRs and LLRs were estimated using SLR. The difference between the allometry coefficients (b) and between the residuals of the models (juveniles, females, and males) was evaluated using the ANOVA significance test. The total length of the species ranged from 1.6 to 9.3 cm. The coefficient of allometry (b) of the WLR of the species is 3.22 and of the LLR is 1.04, demonstrating that H. zebra presents positive allometric growth. The evaluation of the residuals of the models showed differences between ontogenetic stages and between sexes. The development of juveniles is isometric until the first sexual maturation phase and differs in negative allometric for females and positive allometric for males, showing sexual dimorphism in the species. Among the specimens rescued from trafficking, 54.74% were underweight, and 13.16% were under 60% of the expected K value, demonstrating the poor conditions in which these animals are transported by trafficking.
斑马鱼是新谷河流域特有的一种观赏鱼类,具有很高的贸易价值。自80年代末以来,自然种群经历了很高的捕捞压力,最近受到世界第三大水电大坝建设的影响,贝罗蒙特项目。自2004年以来,它被视为极度濒危物种,并被禁止捕获和交易。即使自2004年起禁止捕捞和贸易,该物种仍然是世界上贩运最多的鱼类之一。该物种的生物特征知识对于监测其自然种群和在迁地环境中进行管理至关重要。本研究旨在建立该物种的重量-长度关系(WLR)和长度-长度关系(LLR),并评估被贩运的斑马获救的条件因子(K)。研究于2022年2月至2022年6月在Laboratório de Aquicultura de Peixes Ornamentais do Xingu进行,对1165个标本的WLR和LLR参数进行了估算,并将其分为4种简单线性回归模型:所有标本、仅幼鱼、仅雌性和仅雄性。对巴西联邦警察从贩运中救出的190个标本中的K进行了评估。用单反法估计WLRs和llr。异速生长系数(b)和模型(幼鱼、雌性和雄性)残差之间的差异使用ANOVA显著性检验进行评估。总体长1.6 ~ 9.3 cm。异速生长系数(b)为3.22,异速生长系数为1.04,表明斑马呈正异速生长。模型残差的评估显示个体发育阶段和性别之间存在差异。在第一次性成熟阶段之前,幼鱼的发育是等长的,雌性的负异速生长和雄性的正异速生长不同,显示了物种的两性二态性。在被贩运的动物中,54.74%的动物体重不足,13.16%的动物体重低于预期K值的60%,表明这些动物被贩运的条件很差。
期刊介绍:
The Journal of Applied Ichthyology publishes articles of international repute on ichthyology, aquaculture, and marine fisheries; ichthyopathology and ichthyoimmunology; environmental toxicology using fishes as test organisms; basic research on fishery management; and aspects of integrated coastal zone management in relation to fisheries and aquaculture. Emphasis is placed on the application of scientific research findings, while special consideration is given to ichthyological problems occurring in developing countries. Article formats include original articles, review articles, short communications and technical reports.