The reproductive characteristics of co-occurring freespine flathead, Ratabulus diversidens, and mud flathead, Ambiserrula jugosa, that interact with fisheries across continental shelf waters of eastern Australia were examined. Samples were collected across three depth strata and two locations on a monthly basis over two years. Males of both species matured younger and at smaller total lengths (TL) than females. Estimated TL and age (years) at maturity (L50 and A50, respectively) of R. diversidens also varied between locations, but differences were not related to differential growth. Although some mature individuals of both species occurred year-round, they were most prevalent and gonadosomatic indices greatest, between the austral spring and autumn. Mature R. diversidens almost exclusively occurred in deeper offshore waters, whereas the opposite was evident for A. jugosa. Both species displayed asynchronous oocyte development, and were thus considered capable of spawning more than once throughout each spawning season. Potential batch fecundity was positively related to TL for R. diversidens, but not A. jugosa, possibly due to the small size of the latter species. The sex ratios for R. diversidens varied between locations and length categories, and like A. jugosa the larger categories were skewed towards females, a result of divergent growth between sexes. Macroscopic and microscopic evidence indicated both species were gonochoristic. The data provide new information for fisheries management consideration and contribute to the data-poor international knowledge base of platycephalid biology.

中文翻译：

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澳大利亚东南部大陆架水域 Ratabulus diversidens 和 Ambiserrula jugosa (Pisces: Platycephalidae) 的繁殖特征

共生的自由脊扁头鱼的繁殖特性，鼠尾草和泥鳅，龙舌兰, 与澳大利亚东部大陆架水域的渔业相互作用进行了检查。在两年内每月在三个深度层和两个位置收集样本。这两个物种的雄性比雌性成熟得更早，总长度 (TL) 更小。估计的 TL 和成熟年龄（岁）（L50和一个50，分别）的R. diversidens也因地点而异，但差异与差异增长无关。尽管这两个物种的一些成熟个体全年都出现，但它们在南方春季和秋季之间最为普遍，性腺指数最高。成熟R. diversidens几乎只发生在较深的近海水域，而相反的情况很明显A. jugosa. 这两个物种都表现出不同步的卵母细胞发育，因此被认为能够在每个产卵季节产卵一次以上。潜在批次繁殖力与 TL 呈正相关R. diversidens， 但不是A. jugosa，可能是由于后一种物种的体积小。性别比例为R. diversidens因位置和长度类别而异，等等A. jugosa较大的类别偏向于女性，这是两性增长不同的结果。宏观和微观证据表明这两个物种都是生殖器官。这些数据为渔业管理考虑提供了新的信息，并有助于数据贫乏的桔梗生物学国际知识库。