Greener Futures Sydney Whitaker and Abby Ehlers

Coral reefs of the Florida Keys are seeing a significant decline in coral cover, much more offshore than nearshore. One reason for this decline is the intense competition between hard coral and macroalgae. Parrotfish are extremely important herbivores in the Florida Keys tending to graze on macroalgae. Parrotfish have a complex social structure where all start out as females, with the largest and most dominant fish becoming the supermale. This supermale is the fish that sets the territory for the harem of females, protecting them. The most abundant of these fishes in the Florida Keys are the Redband and Stoplight parrotfish. Knowing what makes up a parrotfish's territory can help us to predict their influence on the reef.

Redband parrotfish and Stoplight parrotfish!
Throughout the middle Florida Keys, data on redband and stoplight parrotfish was collected from 15 paired reef sites, 5 nearshore and 10 offshore.
50 meter transects were laid out across each reef site. Along these transects, site surveys were conducted to determine the percentage of each substrate found on the reef.
Redband and stoplight supermales were followed along the 50 meter transects for 10 minute time periods. Flags were dropped to mark the outer edge of each supermale's territory.
The distance between these flags was measured out, forming a complex polygon representing their territories. Pictures were taken inside and outside the territory surrounding each of the flags.
The pictures were analyzed for substrate percentages in a computer program called CPCe.
The percentage of substrate cover observed between nearshore and offshore.
Left from top to bottom: territory size, average harem size, social structure. Right from top to bottom: difference in turf algae, difference in fleshy algae, difference in coral.
The decrease in coral cover and increase in marcoalgae abundance has caused a shift to favor small, generalist feeders such as the redband parrotfish.

We discovered that redbands become increasingly abundant offshore in harem size and social structure where the coral degradation is observed the most. As coral decline continues to increase and move nearshore, we expect to see a severe shift in the social structure of redband and stoplight parrotfish.

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