Spawning preferences of mahi-mahi

Spawning preferences of mahi-mahi

Spawning preferences of mahi-mahi

Here’s a new article about the spawning preferences of mahi. Mahi is an important fish to both commerce and the ecosystem. Hopefully, more research will be done in this important area.

In the Florida Straits at night, and under a new moon is the preference for spawning mahi-mahi, according to a new study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science.

These new details on the daily life of the highly sought-after migratory fish can help better manage their populations and provide scientists with new information to understand the impacts to the animal from changing environmental conditions.To uncover these important details about the behaviors of mahi-mahi, or dolphinfish, the research team tagged captive spawning fish located at the UM Experimental Hatchery to build predictive spawning models and then used the models with data collected from mahi-mahi tagged in the wild. The study is the first to use acceleration data from remotely transmitting pop-up satellite tags to predict the spawning habitat of a wild marine fish. The UM Experimental Hatchery is the only place in the country where spawning mahi-mahi are kept in captivity.

To build the predictive models, the research team tagged five spawning mahi-mahi (Coryphaena hippurus) at the UM Hatchery and waited overnight to record the timing of when they spawned. In total, 40 individual spawning events were tracked in captivity. Then, they paired the acceleration data collected from the tags with the exact time of spawning to estimate when the animals would spawn in the wild.

To test the models’ capability to estimate where and when the fish spawned in the wild, the researchers tagged 17 wild mahi-mahi off the coast of Miami and two in the Gulf of Mexico.

From an analysis of the satellite tag data, the researchers found that wild mahi-mahi spawn at night, primarily during a new moon at depths greater than they would normally be. The Florida Straits appeared to be an important spawning habitat for mahi-mahi, although the models suggest that some limited spawning takes place further north.

They found that mahi-mahi typically go deeper in the water column at night and are more surface oriented during the day. However, the phase of the moon had an effect on their nighttime depth distribution with a full moon bringing mahi-mahi closer to the surface at night.

They also found that mahi-mahi use behavioral thermoregulation to stay between a relatively narrow temperature window of about 27-28 degrees Celsius (80 — 82 degrees Fahrenheit). When surface waters are warmer, they move deeper and swim northward with the Gulf Stream to regulate their temperature, while fish tagged in cooler months stayed primarily in surface waters and migrated east and west between Florida and the Bahamas, rather than swimming north. They were also found to be the most active at cooler temperatures and in warm waters during a full moon at night.

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Spawning preferences of mahi-mahi

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