Satellite & Acoustic Tracking | Dolphinfish Research Program | Mahi-Mahi | Mahi | Dorado | Dolphin | Dolphinfish
The Dolphinfish Research Program's Satellite Tracking History.
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Satellite & Acoustic Tracking

Another Satellite Tag Goes Full Interval

Article Published April 2023

 

While satellite tags are expensive, they remain one of the principal ways to collect movement data on marine and terrestrial animals independent of direct human contact.  The founder of the Dolphinfish Research Program, Don Hammond, deployed the first satellite tag on a dolphinfish for our program on June 4, 2005.  During his tenure, he deployed fourteen satellite tags, with the majority released using the traditional harpoon method whereby a tag is inserted into the muscle of the fish with a forceful but controlled jab.  Hammond was concerned about the harpoon method being detrimental to the survival of the fish and ultimately leading to lower tag retention.  Consequently, he began experimenting with a new method that required more time with and care of the fish.  He coined the new technique the “thread-through” method in which the tag was essentially buttoned to the fish.  Results from his first five attempts from 2006 through 2008 using the thread-through method, however, did not reveal any differences in survival or retention time on the fish versus the harpoon method.  Then, in 2011, we successfully implemented the thread-through method aboard Missing Angel on a 43″ bull but introduced in-water recovery for the fish and the bull carried the

This 39.5" bull carried a Wildlife Computers mrPAT tag for the full 90-day monitoring period marking the second longest satellite tag retention period obtained for the Dolphinfish Research Program. The tag surfaced off El Salvador on April 10th, 2023.
Daily minimum and maximum temperatures recorded for over 90 days for a 39.5" bull tagged off Guatemala.

tag for our program’s first full monitoring period.  Further modifications were made to the method and, as a result, better results were obtained, including a tag carried for six months, and most recently, three months.  Below is the list of 20 tags deployed by vessels participating in our program that either surfaced after hitting full interval or were recaptured by an angler with the tag still attached to the fish.  While the tags below only represent 25% of our satellite tag movement dataset, if we include premature detachments of greater than a week, which is our lowest preset monitoring period, the percentage more than doubles and the average retention per tag equates to 27 days.  For a species that sits in the middle of the pelagic food web, we feel this method we continue to refine and improve is helping to reveal more information on dolphinfish per satellite tag deployed as well as serve as a distinct contribution to wildlife monitoring.  Interested in sponsoring a satellite tag for our program?  Click here to support our work.

Table:  Vessels that assisted in the deployment of satellite tags that were either carried full interval or were recaptured.  In terms of recaptured satellite tags, three have been retrieved while those denoted “Recapture Unk” indicate fish with tags that transmitted from a vessel in transit or from land.

Rank Tagging Vessel Deployment Location Set Interval Days Status
1 My Three Sons South Carolina 180 182.7 Full Interval
2 Release Guatemala Pacific 90 91.125 Full Interval
3 Yadimar Caribbean Sea 180 55.83 Recaptured Retrieved
4 Missing Angel Caribbean Sea 30 30.38 Full Interval
5 Missing Angel Caribbean Sea 30 30.25 Full Interval
6 Miss Darien Guatemala Pacific 30 30.18 Full Interval
7 Miss Puerto Rico Panama Pacific 30 30.03 Full Interval
8 Tiburon Caribbean Sea 30 30.39 Full Interval
9 Miss Texas Panama Pacific 90 28 Recaptured Unk
10 Lalooli Caribbean Sea 90 20.97 Recaptured Retrieved
11 Lalooli Caribbean Sea 14 14.24 Full Interval
12 Miss Texas Panama Pacific 180 13.5 Recaptured Unk
13 Miss Darien Panama Pacific 20 12 Recaptured Unk
14 Miss Darien Panama Pacific 30 11.5 Recaptured Retrieved
15 CFA Tropical Atlantic 10 9.95 Full Interval
16 CFA Tropical Atlantic 10 9.95 Full Interval
17 CFA Tropical Atlantic 10 9.75 Full Interval
18 Painkiller South Carolina 10 9.78 Full Interval
19 Release Guatemala Pacific 90 9.125 Recaptured Unk
20 Tiz Tiz Panama Pacific 90 2 Recaptured Unk

The History of Satellite Tracking for the Dolphinfish Research Program

Article Published March 2019.

 

The Dolphinfish Research Program’s (DRP) satellite tracking program has engaged sport and small-scale commercial fishermen in the quest to acquire detailed descriptions of habitat use, feeding, and migration data on dolphinfish for the past fifteen years.  Our satellite tracking program consists of four components: raising funds to purchase pop-up satellite transmitters (PSATs) from our sponsors and private donors, fostering the participation of new fishing teams in different locations to aid in the deployment of PSATs, acquiring detailed descriptions of how male and female dolphinfish behave and move, and publishing the results in scientific journals to advance our understanding and management of dolphinfish in order to ensure the future conservation of the species.  Each component presents challenges.

First, while the costs of certain models of PSATs have lowered over the years, the most sophisticated tags capable of gathering the greatest amount of data still cost $5,000 each.  Second, recruiting a captain and their fishing team to help offset outing costs along with giving up a trophy dolphin if caught for science also presents challenges.  Third, once the tag is deployed and the fish is at large, there are a multiude of events that could result in little to no data being collected at all which include, but are not limited to, tag failure, destruction through predation, or damage to the antennae, etc.  Finally, acquiring enough data after overcoming the aformentioned challenges to advance our knowledge of this species through science takes years of work.  Remarkably, over the past fifteen years, our major corporate and fishing club sponsors, private donors, and network of fishing teams have helped the program acquire over 400 days of satellite tracking data from male and female dolphin along the U.S. East Coast, the Bahamas, Caribbean Sea, and Eastern Tropical Pacific Ocean.Each component presents challenges.  First, while the costs of certain models of PSATs have lowered over the years, the most sophisticated tags capable of gathering the greatest amount of data still cost $5,000 each.  Second, recruiting a captain and their fishing team to help offset outing costs along with giving up a trophy dolphin if caught for science also presents challenges.

Third, once the tag is deployed and the fish is at large, there are a multiude of events that could result in little to no data being collected at all which include, but are not limited to, tag failure, destruction through predation, or damage to the antennae, etc.  Finally, acquiring enough data after overcoming the aformentioned challenges to advance our knowledge of this species through science takes years of work.  Remarkably, over the past fifteen years, our major corporate and fishing club sponsors, private donors, and network of fishing teams have helped the program acquire over 400 days of satellite tracking data from male and female dolphin along the U.S. East Coast, the Bahamas, Caribbean Sea, and Eastern Tropical Pacific Ocean.  These data have already been published in five scientific journals and used to describe the overall daily vertical movement strategy and habitat use of adult male dolphinfish, migration routes and pathways among jurisdictions throughout the western central Atlantic Ocean, differences in movement patterns observed from conventional tagging data, gender specific habitat use and movement differences, behavior near fish aggregating devices (FADs), and more.Through the years, the DRP’s tagging technique also evolved from in-water harpon tagging to an on-board thread-through method developed by Don Hammond.

While the DRP has not published a scientific paper on the difference between tagging techniques, observed data indicate more data is acquired and tags achieve their programmed interval more frequently using the new method.  By using this technique in combination with a tagging cradle developed in 2018, our goal is to acquire 200 days of satellite tracking data over the next 12 months working with multiple fishing teams in the Caribbean Sea, Mid-Atlantic Bight, and Eastern Tropical Pacific Ocean.  Gathering these data will allow us to better understand the movements and habitat use of this species in areas that completely lack these data yet fishing pressure on the species is high and abundance appears to be lower than in the past.  Help us fund the acquisition of detailed data records on this vital fish species.  There is no donation too small to help us acquire 200 days of data in the next 12 months.  Donate to our satellite tracking program today.  Click here to donate.

This page is currently being further developed.  Visit our publications page to see reports and scientific manuscripts from data compiled throughout the history of the DRP.

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