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Project Work Plan

Department of Interior USGS GE PES

Fiscal Year 2010 Study Work Plan

Study Title: Development of Trojan Y male technology to control non-native fishes in the Greater Everglades
Study Start Date: 1 October, 2009
Study End Date: 30 September, 2010, with possibility of future funding tied to progress
Duration: 12 months
Location (Subregions, Counties, Park or Refuge): Southern Florida, Everglades National Park, Big Cypress National Preserve.
Funding Source: GE PES
Other Complementary Funding Source(s): None
Funding History: This is a first-year GE PES project
Principal Investigators: Pam Schofield, Frank Chapman (UF), Nick Funicelli
Study Personnel: technicians
Supporting Organizations: University of Florida
Associated / Linked Studies: none

Overview & Objective(s): Dozens of non-native fish species have established throughout south Florida (including Everglades National Park, Big Cypress National Preserve, Biscayne National Park and various state and private lands). Thus far, research on these species has focused on documenting their distributions, natural history and physiological tolerances. Research on control of non-native fishes in South Florida is also lacking, although it is potentially very important and useful to natural resource managers.

At present, the only management techniques available to control non-native fishes are physical removal, dewatering or ichthyocides. Unfortunately, all of these methods negatively impact native fauna as well as the targeted non-native fishes and require a great deal of effort (and therefore, funding). Herein, we propose a research program focused on applying a genetic technique common in aquaculture to control of non-native fishes.

Our program focuses on developing a technique (Trojan Y) to control two species of non-native fishes in South Florida (African jewelfish Hemichromis letourneuxi and Mayan cichlid Cichlasoma urophthalmus). However, the concept can be applied to a wide variety of species, including other fishes (e.g., brown hoplo Hoplosternum littorale), invasive applesnails (Pomacea spp.), the Australian red claw crayfish (Cherax spp.) and the green mussel (Perna viridis).

In the first year of the study we will focus on developing and identifying Trojan Y fish. If we are successful in the first year, we hope to continue our research in subsequent years, including: evaluating behavioural attributes of Trojan Y fish to determine whether: 1) they will mate with  wild males  and 2) whether they interact negatively with native species (e.g., are they more aggressive than wild fish?). We also will be proposing a field experiment in subsequent years, wherein we test the hypothesis that addition of Trojan Y fish will drive the non-native species to extinction.

Specific Relevance to Major Unanswered Questions and Information Needs Identified:

  • The proposed project responds to needs stated in the DOI Science Plan for research to develop effective control methods for exotic aquatic vertebrates.
  • Specific projects that could affect the ultimate distribution and abundance of non-native fishes in southern Florida include the Combined Structural and Operational Plan (CSOP) for modified water deliveries to Everglades National Park and Decompartmentalization of Water Conservation Area 3 (Decomp).

Status: In many aquatic species the process of sex determination is very labile and the sex can be manipulated fairly easily to produce either all-male or all-female populations. Production, for example, of YY males has been accomplished for ornamental species, such as the guppy Poecilia reticulata and goldfish Carassius auratus, as well as aquaculture fishes (e.g., tilapias). We will draw on previous work from aquaculture and the ornamental trade to develop Trojan Y fish of non-native cichlid fishes from south Florida.

We currently have populations of both focal species in our laboratory in Gainesville, Florida and are ready to begin breeding them.

Planned Products: We will present an overview of our progress at the Greater Everglades Ecosystem Restoration meeting in July, 2010. We eventually plan to submit our results to a peer-review journal for publication as well as produce a couple of smaller factsheets (one for USGS, one for UF). We would also like to prepare a website to display our results. This website could be expanded and updated as the project continues.


Title of Task 1: Development of Trojan Y fish for African jewelfish and Mayan cichlid
Task Funding: GE PES
Task Leaders: Pam Schofield, Frank Chapman
Phone: 352-264-3530
Task Status (proposed or active): Active
Task priority: High
Budget and Time Frame for Task 1: 2010
Task Personnel: technicians (USGS and UF)

Task Summary and Objectives: The purpose of this task is to experiment with production of Trojan Y fish of two species of non-native cichlid - Mayan cichlid and African jewelfish.

Work to be undertaken during the proposal year and a description of the methods and procedures:

We anticipate that it will take some time and technique refinement to produce Trojan Y fish for the two focal species. This will include breeding the species in the lab (in Gainesville, FL), feeding with appropriate levels of testosterone, breeding back to the previous generation and identifying Trojan Y fish by determining the gender of their progeny (all male).

Specific Task Product(s):

Peer-reviewed manuscript.
Presentation at GEER July 2010.

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Last updated: 10 April, 2015 @ 11:17 AM(KP)