Knapp Jessica M, Aranda Guillermo, Medina Antonio, Lutcavage Molly
Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, United States of America; Large Pelagics Research Center, University of Massachusetts Amherst, Gloucester, Massachusetts, United States of America.
Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI-MAR), Universidad de Cádiz, Puerto Real, Cádiz, Spain.
PLoS One. 2014 Jun 9;9(6):e98233. doi: 10.1371/journal.pone.0098233. eCollection 2014.
Despite attention focused on the population status and rebuilding trajectory of Atlantic bluefin tuna (Thunnus thynnus), the reproduction and spawning biology remains poorly understood, especially in the NW Atlantic. At present, the eastern and western spawning populations are believed to exhibit different reproductive characteristics and, consequently, stock productivity. However, our study suggests that the two spawning populations, the Gulf of Mexico and the Mediterranean Sea, could show similar reproductive features and spawning strategies. Between 2007 and 2009, gonad samples from female Atlantic bluefin tuna were collected in the northern Gulf of Mexico (n = 147) and in the western Mediterranean Sea (n = 40). The histological and stereological analysis confirmed that sampled eastern and western bluefin tuna exhibit the same spawning duration (three months) but the spawning in the Gulf of Mexico begins one month earlier than in the Mediterranean Sea. Western bluefin tuna caught in the peak of the spawning season (May) showed a similar spawning frequency (60%) to the spawning peak observed in the Mediterranean Sea (June). Fecundity for the Gulf of Mexico fish (28.14 eggs · g(-1)) was lower but not significantly different than for fish sampled in the Mediterranean Sea (45.56 eggs · g(-1)). Our study represents the first comparative histological analysis of the eastern and western spawning stocks whose findings, combined with new determinations of size/age at maturity and possible alternative spawning areas, might suggest basic life history attributes warrant further scientific and management attention.
尽管人们关注大西洋蓝鳍金枪鱼（Thunnus thynnus）的种群状况和恢复轨迹，但对其繁殖和产卵生物学仍知之甚少，尤其是在西北大西洋地区。目前，人们认为东部和西部的产卵种群表现出不同的繁殖特征，因此种群生产力也不同。然而，我们的研究表明，墨西哥湾和地中海这两个产卵种群可能表现出相似的繁殖特征和产卵策略。在2007年至2009年期间，从墨西哥湾北部（n = 147）和地中海西部（n = 40）采集了雌性大西洋蓝鳍金枪鱼的性腺样本。组织学和体视学分析证实，所采样的东部和西部蓝鳍金枪鱼产卵持续时间相同（三个月），但墨西哥湾的产卵开始时间比地中海早一个月。在产卵季节高峰期（5月）捕获的西部蓝鳍金枪鱼的产卵频率（60%）与在地中海观察到的产卵高峰期（6月）相似。墨西哥湾鱼类的繁殖力（28.14个卵·g⁻¹）较低，但与在地中海采样的鱼类（45.56个卵·g⁻¹）相比没有显著差异。我们的研究是对东部和西部产卵种群的首次比较组织学分析，其结果与成熟时大小/年龄的新测定以及可能的替代产卵区域相结合，可能表明基本的生活史特征值得进一步的科学和管理关注。
