DOI: 10.25903/w557-bg51
title: Data for: The use of macroalgal habitats by juvenile rabbitfishes on an inshore reef

description: <p><b>Background:</b>Macroalgal beds are increasingly recognised as nursery habitats for coral reef fish, however, the extent to which they are used as a source of food and/or a refuge from predation remain largely unexplored. Here, we investigate the distribution, feeding behaviour, diet, and predation risk for juvenile rabbitfish in macroalgal habitats on Orpheus Island, Great Barrier Reef. </p>

<p><b>Methods:</b>Data was collected through belt transects and point intercept transects. Behavioural feeding observations were conducted to assess primary dietary targets of juvenile S. doliatus within macroalgal habitats. A minimum of 50 focal observations were conducted within macroalgal habitats on the reef flat at each of the three sites, with all feeding observations being conducted between 0900h and 1600h. After locating a juvenile S. doliatus (i.e., between 10-50mm TL), a diver would estimate the total length (TL) of the individual to the nearest 0.1cm then wait 30 seconds to ensure the fish had acclimated to the diver presence prior to commencing the observation period. Each individual would then be followed for an additional 1-2 minutes (mean = 1.3 minutes) during which the number of bites, and the substratum of each bite was recorded. To supplement the behavioural feeding observations, a total of 16 juvenile S. doliatus between 23-45mm TL were collected from the reef flat using a hand net, barrier net, and a dilute clove oil solution (1:10 clove oil to ethanol). Additionally, 16 juvenile S. canaliculatus, and two juvenile S. spinus between 23-55mm TL were collected opportunistically using a hand net, barrier net, and a dilute clove oil solution. The standard and total length of each juvenile fish collected was measured to the nearest 0.1cm using callipers. Using a dissection microscope the entire alimentary tract of each individual was removed and carefully uncoiled, and the content of the stomach removed and placed into a small petri dish. The stomach content was then carefully spread across the petri dish and a photo was taken of the stomach content at 7-14x magnification. A series of random points were then overlaid on each photo with a minimum of 20 points overlaying dietary content. The dietary item found directly under each point was identified to the lowest taxonomic level. Algal material was identified to genus (where possible) or algal function group (following Steneck and Dethier 1994). Consequently, dietary items were placed into one of six categories: Sargassum, foliose algae, corticated terete algae, filamentous algae, unidentified algae and detritus. Proportion of diet was then calculated by dividing the count of each category by the total count of all categories.</p>

<p><b>This data record contains:</b>
5 csv and 3 excel files:
<ul>
<li>one with count and size data of small fish (<10cm) from two time series </li>
<li>one with count and size data of larger fish (>10cm) from two time series</li>
<li>one with benthic point intercept data from two time series</li>
<li>one of focal feeding observations and proportion of bites taken on substrates</li>
<li>one with proportions of gut content from juvenile rabbitfishes (3 species: <i>S. doliatus, S. canaliculatus, S. spinus</i>)</li>
<li>one with proportions of gut content from juvenile and adult rabbitfishes (3 species: <i>S. doliatus, S. canaliculatus, S. spinus</i>)</li>
<li>one with proportions of gut content from juvenile <i>S. doliatus</i> </li>
<li>one with data from focal feeding observations of only <i>S. doliatus</i></li>
</ul></p>
<p>Files available and archived in Open Document Format (.ods)</p>
<p>Software/equipment used to create/collect the data: R Studio version 4.4.0; Microsoft Excel Version 16.89.1</p>
<p>Software/equipment used to manipulate/analyse the data: R studio</p>