Relative Importance of Nutritional Condition and Refuge Availability for Survival of the Blackeye Goby (Rhinogobiops nicholsii)

The objectives of my research have been to determine (1) whether nutritional condition affects the survival of recently settled recruits of the blackeye goby (Rhinogobiops nicholsii) and (2) whether refuge availability may influence the importance of nutritional condition. For the experiments I conducted at WIES in 2002-05, recruits were fed high or low food rations in the laboratory for 15 d, after which pairs of high- and low-ration fish of the same size were placed on standardized 0.25-m2 rock plots constructed in Big Fisherman Cove, Santa Catalina Island. Laboratory data include condition indices (Fulton's Condition Factor) and growth rates for high- and low-ration fish. In the field, plots were monitored daily to determine mortality over 12 d. Behavioral data were also taken; we recorded whether fish were out, exposed on the plot or hiding, on top of the rocks or between the rocks, and if they were at the exterior of the plot or the interior. Additionally, we recorded the number of recruits that settled to each plot during the daily surveys. Gobies that survived to the end of the field experiment were collected so that field growth rates could be calculated. For experiments examining the interactive effects of refuge availability, pairs of fish were placed on plots in three levels of refuge availability: high, medium, and low. The same types of data were collected during experiments looking at the importance of both condition and refuge availability. In the summer of 2006, laboratory experiments will be conducted looking at the effects of predator presence on stress, feeding behavior, and growth of the blackeye goby. We will cross two levels of refuge availability (low/high) with two predator-exposure treatments (present/absent). Data collected will include cortisol (stress hormone) levels, growth rates, and feeding behavior (how many fish actively feeding, how many fish swim up in water column to food).

本研究旨在明确两大核心目标：其一，营养状况是否会影响黑眼虾虎鱼（*Rhinogobiops nicholsii*）新近定居幼体的存活率；其二，庇护所可获得性是否会调控营养状况对幼体存活的影响效应。

2002至2005年间，本研究于WIES开展实验。实验初期，在实验室中将幼体分为两组，分别投喂高、低两种口粮水平，持续饲养15天；随后将规格一致的高、低口粮组幼体配对，放置于圣卡塔利娜岛大渔夫湾（Big Fisherman Cove）内标准化的0.25平方米岩质实验样地中。

实验室阶段采集的数据包括两组幼体的营养状况指标（富尔顿条件系数（Fulton's Condition Factor））与生长速率。野外阶段每日对样地进行监测，以统计12天内的幼体死亡率。同时同步记录行为数据：记录幼体是否外出暴露于样地、是否藏匿于岩石顶部或缝隙之间，以及幼体处于样地外侧还是内侧。此外，在每日调查中记录定居至各实验样地的幼体数量。

野外实验结束时仍存活的虾虎鱼将被采集，以便计算其野外生长速率。针对庇护所可获得性的交互效应实验，研究者将幼体配对放置于高、中、低三种庇护可获得性水平的样地中。在考察营养状况与庇护所可获得性重要性的实验中，均采集了上述同类数据。

2006年夏季，本研究团队将开展实验室实验，探究捕食者存在与否对黑眼虾虎鱼的应激反应、摄食行为与生长速率的影响。本次实验将设置两种庇护可获得性水平（高/低）与两种捕食者暴露处理（存在/不存在）的交叉设计，采集的数据包括皮质醇（cortisol，应激激素）水平、生长速率以及摄食行为指标（主动摄食的幼体数量、游至水层中觅食的幼体数量）。