A Model of Marine Fish Herbivory in Cold Waters Dietary Choice, Growth, Food Processing and Metabolism of Temperate-Zone Seaweed-Eating Fishes

霍恩博士提出的研究将包括实验，旨在进一步了解为什么温带和高纬度海域的食草鱼类种类如此之少，而热带水域的数量却多得多。试验将重点研究1)海藻韧性在温带草食性鱼类饲料选择中的作用；2)这些鱼类在不同蛋白质含量的饲料中生长；3)温度对这些冷水草食性动物食物加工效率和代谢需求的影响。这些实验将检验一些假设，这些假设构成了温带鱼类食草模型的基本要素。该模型预测1)只有相对不活跃的鱼类才能在低环境温度下通过全海藻饮食满足它们的能量需求，因此2)只有在一年中较温暖的时期，海藻饮食才对较活跃的鱼类在能量上可行。要研究的鱼类是两种丰富的加州近海物种——一种是来自岩石潮间带的迟缓的全年食草动物（Cebidichthys violaceus），另一种是来自邻近海带床群落的活跃的季节性食草动物（sebases mysstinus）。

The research proposed by Dr. Horn will comprise experiments designed to further our understanding of why there are so few species of herbivorous fishes in temperate and high latitudes of the ocean as compared to much larger numbers in tropical waters. The experiments will focus on the 1) role of seaweed toughness in dietary choice of temperate-zone herbivorous fish, 2) growth of these fish on diets of varying protein content and 3) the effect of temperature on food processing efficiencies and metabolic requirements of these cold-water herbivores. These experiments will test hypotheses that form the essential elements of a model of temperate-zone fish herbivory. This model predicts that 1) only relatively inactive fish can meet their energy demands at low environmental temperatures on an all-seaweed diet and therefore that 2) a seaweed diet is energetically feasible for more active fish only during the warmer periods of the year. The fishes to be studied are two abundant inshore California species--a sluggish year-round herbivore (Cebidichthys violaceus) from the rocky intertidal zone and an active, seasonal herbivore (Sebastes mystinus) from the adjacent kelp bed community.