Field: Environmental Science & Biology Title

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Field: Environmental Science & Biology

Title: The Impact of Hunting on Populations of Invasive Lionfish (Volitans pterois and Volitans miles) on the Island of Roatan

Research Proposal

Abstract: The invasion of Lionfish to the Atlantic Seaboard and Mesoamerican Barrier Reef System (MBRS) has significantly disrupted community and population dynamics across the Atlantic Coast and in the Caribbean. Many studies spanning from the late 1980’s to present day have been conducted in an effort to understand this species and its spread. Ever since their release into the wild in the early 1980s they have ravaged numbers of local fish populations spanning from North Carolina to Venezuela. Many of the Caribbean islands have had to deal with the disruption of local reef population structure and dynamics produced by this species because of its nonspecific diet and lack of natural predators. In recent years Roatan, an island located at the end of the MBRS, has begun to feel the effects that the Lionfish invasion has on local reef communities that are integral in sustaining the function of the ecosystem. Currently there are efforts being made to remove the Lionfish before it devastates populations and communities consisting of native fish species which help account for the island’s only real industry, tourism. The purpose of this project is to provide data on whether or not the hunting of lionfish is significantly affecting the invasive population that surrounds Roatan. With this information further measures can be taken in determining the best method for their ultimate containment and/or eradication.

Main Problem/Question: The main question that I will answer is whether or not the hunting of lionfish is having a significant impact on their population sizes. Because of the ever-growing island population and tourism industry on Roatan, the waters have become dangerously overfished and local fishermen have begun to target Lionfish as a potential source of income and sustenance. Although they possess venomous spines they are considered to be very palatable with a taste similar to grouper. One of the problems with obtaining Lionfish is that unlike traditional fishing with a line and net, Lionfish can only be effectively caught by means of spear fishing. In addition, spear fishing is outlawed within the area of the Roatan Marine Park. This law creates a bureaucratic road-block that has provided a safe haven for Lionfish where they can survive and reproduce without the pressure of predation by hunters. Also because they are invasive they do not have any natural predators in the area. The absence of predators and an abundance of prey have led to the expansion of Lionfish populations around the Bay Islands. Local and international efforts are being made to see that their populations are contained before they completely decimate communities of local reef fish. However to accomplish this, more data is needed to better understand what types of methods are actually working to contain and possibly eradicate this problem.

Methods/Approaches: To address the effects of hunting on Lionfish population size, I will conduct a comparative study between areas on the reef where both hunting and diving is sparse to areas where there is documented evidence that hunting is taking place. To do this I plan on choosing a total of twenty different dive sites equally divided between the two types of areas. I will be performing an Atlantic and Gulf Rapid Reef Assessment (AGRRA) because it will allow me to correlate the data that I obtain with previous assessments that have been conducted in the past. AGRRA is a standardized method for the assessment of reef health that, besides fish surveys, also looks at the deterioration of coral as well as the extent and types of algal growth present in a given area. I will be using the protocols used by AGRRA to conduct surveys of Lionfish population sizes. At each one of sites I will enter the water by means of scuba diving and will set up a series of 30 meter lines (transects) in accordance to the AGRRA fish survey protocols. I will then swim along these lines and make note of all the fish that I come across. I will remain at somewhat shallow depths ranging from about 5 to 20 meters (roughly 15-60 feet) because that is the zone that contains the highest abundance of healthy reef which is where Lionfish are typically found. Sites will be chosen on the basis of similarity of depth and topography. To locate the areas for repeated visits I will use an above water GPS unit. Once in the water I will use the same number of transects at each location and will spend the same amount of time at each site. Site visits will be at the same time of the day between 10am and 1pm to maximize the amount of overhead sunlight. After all of the data collection has been achieved I will create a database of all of the different fish sightings and run a statistical analysis on the numbers of Lionfish I see along with those of the reef fish to determine whether or not there is an appreciable difference between the different sites.

Plan of Research: I plan on residing on Roatan for a little over two months from mid-May to mid-July. In this span of time I will be able to conduct a survey at every site twice while making two dives per day. I will only do two sites per day to remove any effects that fatigue may have on data collection. I will have both long distance and on-site supervisors throughout the duration of my research. My University of Iowa faculty and long distance advisor while I am away will be Dr. Stephen Hendrix. When I am in Roatan my on-site advisor will be Jenny Myton who is the Honduras Field Manager for the Coral Reef Alliance. The equipment that I will be using for the AGRRA fish surveys will be provided to me by the Roatan Marine Park. All of the data collection and some of the comparative analysis will be conducted while I am on Roatan. The remainder of the data analysis and the writing up of my findings will be conducted back in Iowa City during the remainder of the summer and the fall semester.

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