Taking a More Adaptable Approach to Dolphin Management
SAFMC Feature Article | 4-9-2024
Known for their dramatic golden, green, and blue neon colors, aggressive pursuit of baits, acrobatics, and delicious fillets, Dolphin (Coryphaena hippurus) are a favorite target of offshore fishermen. Dolphin, also known as Mahi Mahi or Dorado, are found in tropical and temperate waters around the globe and particularly favored in the Caribbean and off the U.S. Atlantic coast. Fishermen often search for “weed lines” or floating mats of Sargassum where baitfish, shrimp, and a multitude of other species seek shelter and offer rapidly growing Dolphin feeding opportunities. Dolphin are one of the fastest growing fish in the sea, reaching sexual maturity in only 3-4 months and growing from larval stage to 8-12-inch fish during that time. They are also short-lived, with a mean less than two years old and a maximum life span of four years.
Dolphin are managed by the South Atlantic Fishery Management Council in U.S. federal waters of the Atlantic Ocean from the Florida Keys to Maine. The Dolphin Wahoo Fishery Management Plan was implemented in 2004, establishing initial management measures for the fishery in federal waters along the Atlantic coast, including catch levels, allowable gear, bag and trip limits, and other parameters.
The most recent management changes to the Dolphin fishery, implemented through Amendment 10 on May 2, 2022, included updates to catch levels and slight modifications to the recreational and commercial sector allocations (93% recreational, 7% commercial). The amendment also addressed gear requirements in the commercial fishery, eliminated the requirement for an operator card, and reduced the recreational vessel limit for Dolphin from 60 fish to 54 fish (excluding headboats). The recreational bag limit was not modified and remains 10 fish per person per day. A 20-inch fork length minimum size limit is in place for federal waters off the coast of South Carolina, Georgia, and east Florida. The stock is not classified as overfished nor undergoing overfishing.
Dolphin are a short-lived and highly productive stock. Such species can generally withstand more fishing pressure than less-productive stocks. Since their productivity is thought to be largely environmentally driven, the abundance and availability of Dolphin is sporadic from year-to-year. In addition, as a highly migratory species, Dolphin are harvested across international boundaries, limiting the capacity of the U.S. to manage the entire stock. Data are also limited as not all countries collect and report data on Dolphin. Consequently, these traits and data limitations have hindered the development of a comprehensive stock assessment. A more effective approach could be the use of a management strategy evaluation (MSE) to identify management procedures that may work best to address management objectives for Dolphin managed by the Council.
Management Strategy Evaluation – Allowing Flexibility in Management Approaches
The high demand for Dolphin, both recreationally and commercially, and recent concerns over user conflicts, highly variable availability, and international harvest, has sparked the need to consider a more flexible and adaptive management approach. NOAA Fisheries is currently conducting a MSE to develop innovative ways to manage Dolphin in the U.S. Atlantic. The goal is to design an approach that maximizes stakeholder objectives, reduces conflicts, and best fits the life history of Dolphin. The MSE aims to:
- Predict the amount of Dolphin that will be available each year
- Maximize the usage of Dolphin across sectors and regions
A management strategy evaluation is a way to test fishery management strategies, which may include regulations or harvest control rules, before implementing them. The approaches tested are called management procedures. These management procedures specify how different management actions will be adjusted based on the changing behavior of the stock. For example, in years when the stock availability is high, the fishery can adapt to take advantage of the high abundance.
The management procedures are tested on their abilities to respond to a variety of different environmental, data, and stock scenarios to help ensure they are appropriate for application in the real fishery. Each hypothesized scenario is quantified in an operating model. Candidate management procedures are tested across a suite of different operating models that include historical and future uncertainties about the system dynamics.
Stakeholder involvement in the MSE process is crucial. One on the criteria for evaluating the management procedures is how well they meet certain objectives for the stock. These objectives are defined by stakeholders and reflect what priorities they value in the fishery. The MSE process for Dolphin has included a series of stakeholder workshops held along the Atlantic coast in 2023. In addition, a Dolphin MSE Stakeholder Working Group was formed in early 2024. Members will work with MSE analysts to refine initial management procedures, finalize and rank management objectives, and provide input on management procedure performance. Members represent various regions and sectors.
While the MSE may not reveal a specific outcome or strategy that meets every management goal for the stock, it does allow for the comparison of different management options and evaluation of their biological, social, and economic tradeoffs. The process is designed to test potential management procedures to see how they might perform under many possible scenarios. Learn more about the MSE process for Dolphin in this recent feature from NOAA Fisheries.
Dolphin Management Looking Forward
Based on public input received during the development of Dolphin Wahoo Amendment 10, the Council began development of Regulatory Amendment 3 in 2021 with options to extend the current 20-inch fork length minimum size limit for Dolphin further north, potentially from North Carolina through Maine. Currently, the minimum size limit only applies in federal waters from the east coast of Florida through South Carolina. The amendment also includes options to reduce recreational retention limits (bag or vessel) for private and/or for-hire vessels, and remove for-hire captain and crew bag limit retention for Dolphin.
During its December 2023 meeting, the Council decided to pause development of Regulatory Amendment 3 until a report is available from the Dolphin MSE or until the December 2024 meeting of the Council, whichever is earlier. Meanwhile, recognizing public concerns about regional declines in the availability and quality of the Dolphin fishery, the Council is also looking at potential sources of declines in the availability of Dolphin and efforts to collectively manage Dolphin, both regionally and internationally.
The Caribbean Fishery Management Council recently developed management actions for the commercial and recreational Dolphin fishery that would apply to federal waters off the coast of Puerto Rico and the U.S. Virgin Islands. An update on these efforts was provided to the South Atlantic Council during its June 2023 meeting.
The Council will continue to receive updates on the MSE from NOAA Fisheries and is scheduled to address Dolphin management again during its December 2-6, 2024 meeting in Wrightsville Beach, NC.
