Biological armours are potent model systems for understanding the complex series of competing demands on protective exoskeletons; after all, armoured organisms are the product of millions of years of refined engineering under the harshest conditions. Fishes are no strangers to armour, with various types of armour plating common to the 400–500 Myr of evolution in both jawed and jawless fishes. Here, we focus on the poachers (Agonidae), a family of armoured fishes native to temperate waters of the Pacific rim. We examined armour morphology, body stiffness and swimming performance in the northern spearnose poacher (Agonopsis vulsa) over ontogeny. As juveniles, these fishes make frequent nocturnal forays into the water column in search of food, while heavily armoured adults are bound to the benthos. Most armour dimensions and density increase with body length, as does body stiffness. Juvenile poachers have enlarged spines on their armour whereas adults invest more mineral in armour plate bases. Adults are stiffer and accelerate faster than juveniles with an anguilliform swimming mode. Subadults more closely approximate adults more than smaller juveniles, with regards to both swimming and armour mechanics. Poacher armour serves multiple functions over ontogeny, from facilitating locomotion, slowing sinking and providing defence.

中文翻译：

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游泳和防御：装甲鱼（Agonidae）个体发育中的竞争需求


生物装甲是理解对保护性外骨骼的一系列复杂竞争需求的有效模型系统；毕竟，装甲生物是在最恶劣的条件下经过数百万年精心设计的产物。鱼类对盔甲并不陌生，在有颌和无颌鱼类的 400-500 迈尔进化过程中，各种类型的盔甲都很常见。在这里，我们重点关注偷猎者（Agonidae），这是一种原产于环太平洋温带水域的甲鱼。我们通过个体发育研究了北方矛鼻盗猎者（Agonopsis vulsa）的盔甲形态、身体刚度和游泳性能。作为幼鱼，这些鱼经常在夜间进入水体寻找食物，而全副武装的成鱼则被束缚在底栖动物中。大多数装甲尺寸和密度随着车身长度的增加而增加，车身刚度也是如此。青少年偷猎者的盔甲上有较大的刺，而成年人的盔甲底部则有更多的矿物质。成鱼比幼鱼更僵硬，加速更快，具有鳗鱼状的游泳模式。在游泳和装甲力学方面，亚成体比体型较小的幼体更接近成体。偷猎者的盔甲在个体发育过程中具有多种功能，包括促进运动、减缓下沉和提供防御。