Caribbean Sea

November 2025

Fishing aboard Caribbean Fishing Academy, a charter boat based out of San Juan Bay, Puerto Rico, Captain Daryl Wiley and our team were able to deploy a Wildlife Computers miniPAT tag on a 34″ female caught adjacent to a floating tanker 18 miles off the north coast.  This fish carried the tag for approximately 569.10 miles in 23.45 days.  This movement record shows the female moving predominately to the north into the Sargasso Sea and eventually trending toward the west-southwest and the start of the Antilles Current, a pathway we have suspected is a major route dolphinfish take during fall, winter, and spring back toward the Gulf Stream just off the U.S. East Coast.  This record is another result generated from our work with the Caribbean Fishery Management Council.  Click here to learn more.

October 2025

Earlier this month, Dolphinfish Research Program (DRP) personnel embarked on a tagging expedition to Puerto Rico to enhance data collection on dolphin.  In two 8-hour outings, fishing off San Juan, Captain Daryl Wiley and our team tagged and released 17  dolphinfish and a blue marlin aboard Caribbean Fishing Academy, a fishing charter based in San Juan.  These outings contribute to our and grant work with the Caribbean Fishery Management Council (CFMC), which began in September 2024.  During these recent outings, we were able to deploy three satellite tags.  On the first outing, we deployed a satellite tag on a 34″ female dolphinfish, and on day two, we deployed tags on a 48″ male and a 125-pound blue marlin caught at the same location.  We opportunistically deployed the tag on the blue marlin to investigate dolphin-marlin predator-prey relationships, given that both the bull and the blue were caught and released at the same location.  As for the deployments on the dolphinfish, they mark the 12th and 13th of 30th toward our work with the CFMC.  Our objective with our work with the CFMC is to focus conventional and satellite tag deployments in three key tagging zones: the Mid-Atlantic Bight, Puerto Rico, and the United States Virgin Islands.

Thus far, through 15 outings over the past year, we have tagged and released 295 dolphinfish, deployed 13 satellite tags, and generated 17 movements between the aforementioned zones (image above).  This progress contributes to our overall work to better understand the impacts of changing environments and fishing pressure on dolphinfish in the U.S. Caribbean Sea and beyond.

March 2025

On March 8th, we received our 12th overall satellite tag recapture report and 3rd for dolphinfish tagged off La Parguera, Puerto Rico.  The tag recovered on March 8th was attached to a 40.5″ female that was caught by a recreational vessel named Contraste during La Parguera’s coveted seasonal dolphinfish tournament.  The tag was reported to us by Anibal Mercado, an employee of the University of Puerto Rico’s Department of Marine Science, and the angler, Joaquin Oliver, kept the tag safe after he discovered it on his fish.  Joaquin caught the fish in a school with a bull and two other females.  We originally tagged the female, which measured 39″ when released, on February 6th with captain Jesus Duran and mate Emmanuel Markham in a location that was only 18 miles away from where it was recovered.  We caught and released the female with another 41″ female that was also fit with a satellite tag.  Both fish were caught in the same school.  The tag associated with the 41″ female surfaced 40 miles to the east-southeast after remaining with the fish for 17.88 days.  This recaptured fish, along with a third that we tagged and released on February 5th, all remained in the area post-release, a result that we have not previously observed from our tagging work off La Parguera.  The 40″ bull we tagged on February 5th was released with a Wildlife Computers miniPAT tag which produced an estimated geolocation track.  This track (see below) showed the bull headed ~42 miles to the east-southeast and returned back to the area after nine days.

While our previous geolocation tracks acquired off of southern Puerto Rico showed dolphinfish can linger for a few days, this was our program’s first track that showed a fish remained in the area for more than a week with the recaptured fish revisiting the area after a month.  In fact, all previous satellite tag movement records acquired from tagging work off La Parguera (n = 11) provided westward movements with popup locations ranging from 100 to 900 miles to the west, with two fish recaptured at fish aggregating devices (FAD) south of the Dominican Republic.  Since 2019, when our program resumed satellite tracking work south of Puerto Rico, 27% of tags have been recaptured (3 of 11), a recapture rate higher than off Panama in the Eastern Pacific Ocean (11%; 6 of 54).  The high recovery rate of large dolphinfish tagged south of Puerto Rico shows that the species is under intense fishing pressure in the northeastern Caribbean Sea.

February 2025

Our last successful satellite tag deployment on a large dorado south of Puerto Rico was April 1st, 2022. We deployed 2 tags on April 1st and 3 tags the day before. During the spring of 2021, we were able to get 2 tags out. During 2020, we did not get to travel due to the pandemic, but in 2019, we got 3 tags out south of PR. Overall, from 2019 through 2022, fishing for dorado south of PR was decent, and in fact, 2022 was really good. Yet, in the 27 outings from the end of the spring 2022 through the springs of 2023 and 2024, we did not encounter one large dorado south of PR or even around PR, that allowed our team to deploy a tag. Thankfully, the lack of deployments finally ended earlier this month when we efficiently found schools of large fish and got 3 tags out. These tags were deployed in conjunction with our project with the Caribbean Fishery Management Council. The deployments this past month bring us to a total of 18 on dorado fishing out of La Parguera, Puerto Rico. A special thanks to Captain Jesus Duran and mate Emmanuel Markham for their assistance with this work. Our team has deployed 14 tags with their assistance. Check out his charter, Lalooli Fishing Charters, out of La Parguera. Then, last week, in association with the same project, we successfully deployed our 8th and 9th tags with Captain Cook Charters and Captain Dave Claeys and his son Cai Claeys (@cai_claeys), who is an amazing mate. They put us on the fish and we deployed Microwave Telemetry 6-month geolocating tags on a 45″ female and 42″ bull from the same school. Check out Captain Cook Charters (@captaincookcharters) to fulfill your fishing dreams off of beautiful St. Croix. They are located in Green Cay Marina.

September 2024

By: Wessley Merten

NOAA Fisheries is partnering with the eight Regional Fishery Management Councils, including the Caribbean Fishery Management Council (CFMC), to plan and implement the U.S. Federal government Inflation Reduction Act (IRA), Climate-Ready initiative.  The program will tackle several critical areas focused on the impacts of climate to confront climate-change impacts using science-based management and pursuing conservation of the nation’s marine resources.  One of the priorities for the CFMC is to better understand the effects of climate and fishing pressure on dolphinfish in the U.S. Caribbean Sea and Mid-Atlantic Bight (MAB) and we are excited to announce that our project, entitled “Understanding the impacts of climate change and fishing pressure on the dolphinfish (Corpyhaena hippurus) in the U.S. Caribbean and beyond”, was awarded to our research foundation earlier this month.  Over the next 27 months, our program will embark on our most intensive satellite tracking initiative in the Atlantic over the course of our 23-year history; we are setting out to deploy 30 satellite tags on sub-adult and adult dolphinfish  September 17th,

between Puerto Rico (10), the United States Virgin Islands (10), and the Mid-Atlantic Bight (10) to better understand how the species moves within and to the U.S. Caribbean Sea. We are also pleased to report that on September 17th, fishing aboard Captain Geof Lewis’s vessel, Calm Chaos, with son and mate Richard Lewis, as well as a team from Phenom Yachts, we deployed our first satellite tag associated with this project on a 34″ bull 70 miles south of Rhode Island.  With this deployment, and the 29 ensuing deployments, we intend to strengthen the CFMC efforts to better integrate scientific tools to prepare for and respond to climate change and develop management measures or processes to better understand climate change and fishing impacts on dolphinfish in the region.  Below are the overall objectives of this research project:

• Enhance the understanding of dolphinfish migration patterns by collecting and analyzing satellite tracking data on the species movement patterns in three different regions: Puerto Rico, United States Virgin Islands, and Mid-Atlantic Bight (MAB).  Compare this information to oceanographic, meteorological, and environmental databases.
• Link and evaluate obtained results with existing fishery dependent and independent data obtained through the Dolphinfish Research Program, increasing the empirical information through enhancing stakeholder participation, and engaging fishers and graduate students in field work, and analysis.
• Provide management recommendations to improve the species fisheries management regulations to the CFMC which could also be applicable to other councils such as the Gulf, Mid-Atlantic Bight, and South Atlantic Fishery Management Councils (SAFMC).

March 2024

By: Wessley Merten

In the Fall of 2016, our group initiated a volunteer vessel catch and effort program to monitor charter, recreational, and small-scale commercial catch and effort. This research is funded by the Puerto Rico Department of Natural and Environmental Resources.  When examining by year over year between 2016 and 2023, annual catch success from a total of 2,596 fishing trips has decreased from 65% to 49%. Annual catch success is defined as the number of trips anglers landed one target species (dorado, tuna, or wahoo) or released a billfish. When looked at another way, the percentage of annual trips that resulted in no catch for an outing (i.e., getting skunked) has increased from 35% to 51% over the period.  In terms of angler catch success, and upon review of 118 offshore research outings taken over the past 14 years around the island, the 2023-24′ season around Puerto Rico has been the worst year we have documented.  While the reason(s) for the poor fishing off PR during 2023-24′ have yet to be determined, the evidence presented in the DRP’s March 2024 newsletter reiterates the importance of our ongoing citizen-driven data collection and should signal to fishery managers throughout the WCA that improvements in dolphinfish management in the region is needed now.

October 2023

By: Wessley Merten

Recently, the Dominican Republic submitted data to the Food and Agricultural Organization (FAO) that estimates their 2021 commercial dolphinfish landings to be 880.7 metric tons or 1,940,000 lbs. We were told that the estimate of commercial dolphinfish anglers in the Dominican Republic is 2,369 based on communication with the DR Government. If the 2021 landings data are divided by the number of anglers, the result is annual landings estimate of 818 lbs per angler, a value that we believe is extremely low relative to data that our program is collecting. Beginning this past July, our program program began monitoring the catch of two commercial anglers in the Dominican Republic. One was surveyed once several years ago, and the other has never been surveyed by the government.  Data presented here for angler 1, an individual who fishes offshore for dolphinfish, amounts to landings of 11,173 lbs across 35 outings.  On average, angler 1 landed 311 lbs per outing (min: 40 lbs; max: 700 lbs), and anecdotally, this angler said the fishing has been slow.

For angler 2, an angler who fishes no more than 6 miles offshore, across 5 coastal outings in early October, this angler has already landed 445 lbs of dolphinfish and averages 89 lbs per outing.  Based on these statistics, our confidence in the 2021 DR FAO landings estimate is still low, but they do provide further evidence that the decrease in Florida recreational landings in recent years could be related to a dramatic rise in landings up current in the Western Caribbean Sea. Currently, only the DR, Mexico, and Cuba report dolphinfish specific landings in the Western Caribbean Sea, and the latter two submitted 13,200 lbs and 19,800 lbs, respectively, as their 2021 FAO estimate.  Mexico and

Cuba’s values are only slightly higher than the amount of landings from the offshore angler we are monitoring in the Dominican Republic that we surveyed across 35 outings.  Are commercial landings for dolphinfish in Mexico and Cuba really that low now?  Two decades ago, both Cuba and Mexico were recording annual commercial landings of dolphinfish greater than 660,000 lbs, which means commercial landings have dropped at least 98% in these nations. Unfortunately, over this same time period, it is unknown how much dolphinfish were landed by recreational fleets, including for-hire charters, yet participants in our tagging program in Mexico have shared with us that charter boats are landing more than 2 dolphinfish per trip, Mexico’s daily bag limit, and we have had a few dolphinfish recaptured in Cuban waters by commercial anglers. These observations, along with the increase in urban sprawl and population size in major resort communities in Mexico and other resort locations around the Western Caribbean Sea, further stress the need to enhance our society’s ability to properly document exploitation patterns for dolphinfish in the region if we want to bring back dolphinfish abundance and conserve the resource for generations to come.

July 2023

By: Wessley Merten

In 2019, we resumed a study to document the movements of dolphinfish in the Caribbean Sea by deploying satellite tags on adult dolphinfish during the spring run off the Southwest Coast of Puerto Rico (SW PR).  This research builds on earlier tagging work we did in the same area between 2011 and 2014 in which three satellite tags were deployed.  In total, 15 satellite tags have been deployed, with 12 deployed since 2019.  Of those 12, two were recaptured south of the Dominican Republic, which equates to a 16% recovery rate.  Even if we assess the recovery rate based on all PSATs deployed off SW PR, since 2011, two of 15 tags recovered equates to a 13% recovery rate.  Both tags were recaptured by anglers fishing FADs south of DR, and in both instances, we awarded those anglers with several hundred dollars to successfully ship us the tags.  Aside from the importance of documenting the recovery rate of satellite tagged fish moving west from PR waters, the information gleaned from these tags as well as our ability to refurbish and redeploy the tags enhances our ability to learn more about this important pelagic fish and the dolphinfish fishery in the region.  Interestingly, the 44″ female followed a similar track as the 47″ male recaptured in 2019 (click here

or that story).  Similar to the bull’s movement, while not considered a broad-scale movement, the 625-mile long track showed us that this cow used a variety of habitats throughout the region at a varied pace.  Following a rapid daily movement northwest into the Mona Passage after being released, the succeeding four days were spent just offshore Rincon, Puerto Rico, and northeast of Isla Desecheo from April 1st until April 4th.   The fish then moved northwest into the tropical Atlantic before moving back south through the Mona Passage at a steady pace of 27 miles per day.  The cow moved from the tropical Atlantic in the northern part of the Mona Passage to the Caribbean Sea in the southern part of the Mona Passage in three days.  From here, the cow moved westward and seemed to orient relative to deep depth contours associated with the continental shelf.  Prior to the six-day westward movement to the recapture site, there were three instances when the fish moved southeast for one to two days moving against the prevailing southeasterly tradewinds.  Anglers fishing south of Puerto Rico have provided accounts of outings where they seemed to follow schools, called cardumens in Puerto Rico, east.  These short jaunts confirm that this cow was making short easterly movements, but it is unknown whether or not the cow was schooling.  After the final short southeasterly movement, the fish moved west 150 miles in one day, which is the fastest daily movement obtained over the monitoring period.  That distance traveled in one day equates to an hourly movement rate of 6.25 miles per hour.  However, when the cow was south of DR, the average daily movement rate slowed down to 21 miles per day before the fish was recaptured a FAD south of Barahona, DR.  Total time at liberty between deployment and recapture was 21.97 days.

In terms of depth use, the female’s vertical habitat use was a stark contrast to the habitat use observed for the 47″ male tracked in the same area in 2019.  For the female, aside from repetitive deep diving behavior off Rincon for a few days, deep dives for extended periods of time were lacking for the cow.  While the deepest observed depth for the cow was 150.6 meters, similar to the 149.3 meters observed for the big bull, vertical water column use ranged from 0-50% of that depth.  The female did show deeper diving behavior at night, which was similar to the 2019 bull, but the bull consistently dove to depths at or near the maximum depth during the 55-day track.  This is the first time our program has acquired geolocation tracks that were similar in path in the same area between sexes for dolphinfish which makes these datasets a unique glimpse into behavioral differences between adult male and female dolphinfish.  One caveat to disclose is the entire dataset was acquired for the 47″ bull.  This led to a very precise depth record for where the bull was at any given time during the monitoring period.  For the cow, we opted for the 15-minute standard rate dataset to allow for more timely and less costly tag refurbishment.  Despite the major differences in sampling rate between datasets, depths recorded at 15-minute intervals would still show extensive depth use, which was not the case for the female’s record.  These records and observations obtained excite us as we forge ahead to tag and release more healthy adult dolphinfish off Southwest, Puerto Rico, in the future.  The anglers involved in this work off Southwest, PR, are as follows:  Captain Manuel Botello (2011); Captain Milton Carlo (2011-2014); Anibal Santiago (2011-2014); Captain Jesus Milo Duran (2019-present); Captain Dan Hack (2021-present); Captain Yunyi Gonzalez (2022-present); Anglers Dagobuerto Rodriquez, Emmanuel Markham, Jose Lebron, Irving Baez, Alexis Alfalla.

October 2022

By: Wessley Merten

Data collection on highly migratory fish stocks (HMS) is difficult.  For dolphinfish, while not officially recognized by regional fishery management bodies as an HMS species, it is no different.  To collect data on dolphinfish, for the past two decades, the Dolphinfish Research Program (DRP) has distributed more than 60,000 tags to thousands of anglers throughout the Atlantic, Pacific, and Indian Oceans to compile basic statistics on distribution, occurrence, movements, and growth.  In August 2021, the Sandman Fishing Team reached out to us to get involved.  While their fishing team was one of 366 vessels to receive tags from the DRP in 2021, it was the only new tagging vessel to generate eight recoveries through their dedication to tagging over the past year.  Last October, we showcased their efforts in our monthly newsletter (click here for that story), and over the last month, four additional Sandman tagged fish have been recovered.  The following summarizes all recoveries:

• All occurred within Dominican Republic (DR) waters in the fall
• All were reported by DR commercial anglers
• 7 of 8 recaptures occurred at fish aggregating devices (FADs)
• All recovered fish were originally tagged at FADs

• Tagged fish in DR waters, on average, grew 2″ while at liberty
• One tagged off Florida grew 10″ in 200 days and moved to DR
• Movements were to the northwest, averaging 13.52 miles/day
• Sandman’s recapture rate is 6.5% (8 of 122 tagged)

Sandman’s high recapture rate rivals our top tagging teams (Killin Time II and WamJam) in the Florida Keys, and like in the Keys, is indicative of high fishing pressure but off the north coast of DR.  Another factor that could be contributing to the high recapture rate may be due to horizontal compression of the species due to the high number of FADs distributed around DR.  Wilson et al. (2020), estimated that 2,500 FADs were active off DR, which is the highest number of FADs present in any Caribbean Island nation by fourfold.  Is it then coincidental that commercial dolphinfish landings in DR have increased 70% since 2014 during the time period in which FAD use has proliferated?

In the most recent year (2019) of reported landings to the Food and Agricultural Organization (FAO), the Dominican Republic ranked second in terms of commercial dolphinfish harvest, but 3 times lower than France, the top commercial dolphinfish fleet in the Western Central Atlantic Ocean (WCA).  The U.S. directed dolphinfish fleet ranked 9th in the WCA and was 4 times lower than DR and 13 times lower than France.  This information is reported here because, recently there have been several articles published that blame the U.S. directed commercial dolphinfish fleet for the decrease in abundance and size of dolphinfish in the Florida Keys/South Florida region.  What these articles failed to report, quote, or cite, however, is that less than 1,000 miles away, dolphinfish landings have increased dramatically during the same time period.  Even more shocking is these skewed reports failed to mention that the U.S. recreational (for-hire and private) fleet landed 13,053,698 pounds of dolphinfish in 2019, 4.4 times higher than the largest commercial harvester of the species in the WCA (France at 2,949,781 pounds), nearly 13 times the Dominican Republic commercial industry, and 57 times the U.S. commercial fleet.

While there remain several key unknowns with regards to the harvest of dolphinfish in the region (click here for that analysis), what some recent calls to action fail to take into account are the biological attributes of dolphinfish.  Many of these attributes, such as an early age of maturation, high reproductive capacity, fast growth, large size at maturity and short lifespan, suggest it can sustain considerable rates of exploitation if the population is managed properly.  But, in DR, there is no management plan for dolphinfish.  Across the Caribbean Sea, there is no management plan for dolphinfish.  In the Gulf of Mexico, there is no management plan for dolphinfish.  From North Carolina north, and throughout the Caribbean Sea and Gulf of Mexico, any size dolphinfish can be harvested.  The use of j-hooks and dropback techniques, both of which are detrimental to the species, remain prolific among recreational and artisanal anglers throughout the region.  Additionally, there remains a lack of participation among anglers to provide relevant data for scientists and managers to consider to examine fishing pressure and dynamics exuded on the WCA stock, data that is needed to better manage the species.

Sandman’s recent participation and results showcase how individuals can make a difference through our tagging program on the knowledge of the WCA dolphinfish stock.  Their participation sheds light on real issues that face the WCA stock and can be used as evidence to drive constructive management of the species for the future and for all stakeholders.

May 2022

In 2019, our tagging program reinitiated a study to describe the movements of dolphinfish within the broader Caribbean Sea by deploying more satellite tags off the southwest coast of Puerto Rico.  Building off of work that began in the area in 2011, we deployed three  satellite tags in 2019, and one of them was recaptured at a fish aggregating device (FAD) south of Isla Sanoa, DR, on May 20th, 2019.  That was the first time a satellite tag had been recovered for our tagging program, and we were able to successfully retrieve the tag and acquire a very detailed record of the movement of the 47″ bull.  Click here for that story.  Recently, we deployed five tags in the same area, and another was recovered at a FAD, but this time 20 miles southeast of Barahona, DR.  Thankfully, we were able to compensate the anglers who recovered the 44″ female (pictured below being released), and they shipped the geolocating tag back to us.  While we have not yet processed the track, with this article we share the 21-day point-to-point movement as well as some details on the vertical behavior of this female while at large.  During the first 12 days post-release the female made frequent and repetitive dives  deeper than 75 meters.  During the last 9 days before being recovered, however, the female only exceeded a depth of 25 meters three times.  Aside from the fact that two out of 14 spring satellite tags deployed off southwest PR since 2019 were recovered within 30 miles of each other at FADs south of DR, a trend of decreasing depth use from east to west is similar to that of the bull, which suggests that FAD presence may have an effect on the vertical movements of dolphinfish monitored in this region.  A special thanks to Lalooli and Liqueo fishing teams (pictured above) based out of Boqueron, Puerto Rico, for their help with the recent tag deployments.

April 2022

Our quest to describe the movements of dolphinfish within the Caribbean Sea continued in April with the Lalooli and Liqueo fishing teams based out of Boqueron, Puerto Rico.  Those crews deployed a total of five popup satellite archival transmitters on adult male and female dolphinfish ranging in size from 38″ to 48″ fork-length.  This work began nearly a decade ago, and so far, we have successfully deployed 16 satellite tags and have received several conventional  recoveries. Of the tags recently deployed, one popped up on its scheduled date and another was recaptured at a fish aggregating device southeast of Barahona, Dominican Republic.  Updates on these movement records will be posted soon.

When Captain Jesus Duran and mate Dagobuerto Rodriquez of Boquerón, Puerto Rico, posed for a picture with a popup satellite archival transmitter (PSAT) on March 25^th, 2019, we didn’t think we would ever see the tag again.  That day, while fishing 20 miles south of Cabo Rojo Lighthouse, they attached the PSAT to a beautiful 47” male dolphinfish.   The fish was hooked on a ballyhoo that was left drifting behind Yadimar, a 25’ Grady-White, by photographer Anthony Dooley of Rincón, while at the same time we fought, landed, and tagged a 38” female dolphinfish with another PSAT.  Over the past decade, with funding from Puerto Rico’s Department of Natural and Environmental Resources, our tagging program, known internationally as the Dolphinfish Research Program, has deployed more than 20 PSATs on adult dolphinfish around the island.  Attaching the devices to these fish allows us to garner a glimpse into their daily behavior as well as short and long-term migration patterns, information that is useful for improving dolphinfish management and advancing species conservation.  The process of deployment, however, is nerve-wracking.  Generally, once the fish is revived and released, you can be certain that the costly tag you just attached to your fish will never be in your possession again.  Well, that is, at least, what we thought.  A few months after we tagged our 47” bull, we noticed that tag was transmitting from land.  How could that be?  Well, simply put, another fishermen caught it and they brought the tag home!  For the first time in this

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20-year study, we were able to successfully recover a PSAT.  In most cases, having a fish captured that is carrying a PSAT is not advantageous to our research.  However, in this case, the fish carried the tag for 57 days, and by retrieving the tag, we acquired a more detailed record of the behavior of the fish over that time period than if the tag had not been recovered.  Typically, a tag detaches from a fish after a monitoring period that we set (e.g., 30, 90, or 180 days) and we retrieve a portion of data recorded on the device while attached to the fish via satellite uplink.  In the case of our recovered PSAT, we were able access the tag’s hard-drive to download the entire dataset.  This occurrence, to the best of our knowledge, is the first-time a PSAT has been recovered on a dolphinfish, and it represents one of the most detailed daily records of a bull dolphinfish in our world’s oceans.  This information is critical in order to better understand how large dolphin behave in the Caribbean Sea, a region that lacks this information, and to ultimately ensure the long-term sustainability of the dolphin fishery throughout the region.

While not considered a broad-scale movement, the 445-mile long track showed us that this bull used a variety of habitats throughout the region at a varied pace.  For the first six days, the fish lingered within a few miles of the shelf edge off La Parguera before moving northwest into the Mona Passage on March 31^st.  Once in the Mona Passage, the fish meandered for 12 more days off the western insular platform, due west of Boquerón Bay and within the vicinity of Abrir La Sierra, an important shelf-edge reef system off the west coast.  After the fish utilized the shelf and open ocean coastal waters off southwestern Puerto Rico for 18 days, it began more direct and transitory movements toward the northwest bisecting the Mona Passage in seven days.  The fish swam an average of 12 miles per day in the middle of the Mona Passage and then slowed to an average of six once the fish arrived off Punta Cana on April 17^th.  The fish then swam south along the eastern coast of the Dominican Republic before heading back into the Caribbean Sea southeast of Isla Saona on April 26^th, four days shy of spending the entire month of April in the Mona Passage.  For the remaining 24 days of the track, the fish occupied a 2000 square kilometer area south of La Romana, DR, which was half as much area covered during the first part of the track off PR and while in the Mona Passage.  Within DR coastal waters, the fish revisited previously visited areas at 3 to 20 day intervals.  The fish was captured at a fish aggregating device (FAD) south of Isla Saona on May 20^th.

During the 18 days the fish was off southwestern Puerto Rico, it experiences its deepest and most complex diving behaviors.  On March 28^th, a day when the bull was estimated to be right along the shelf break off La Parguera, the bull’s average daily depth was only 14 meters but during night average depth use extended to 51 meters with several dives taken between 100 and 142 meters.  During sunrise and sunset the bull was also observed to dive to 57 and 116 meters with the brightest time of day spent in depths less than 36 meters.

While along the west coast of Puerto Rico on April 6^th, the bull dove to its deepest depth, 149.3 meters, of the entire 57-day.  Two days later, the fish displayed similar diving behavior as observed off La Parguera while the bull was estimated to be off the shelf edge west of Boquerón Bay.  On that day, the deepest depths to 129 meters were registered around sunrise.

The bull’s deep diving behaviors during sunrise, sunset, and night continued through the middle section of the Mona Passage near el Pinchincho, but when the fish arrived off Punta Caña and the eastern shores of the Dominican Republic (DR) on April 17^th, depth use had decreased to a daily average of 2 meters and the fish only ventured to depths below 50 meters during 20 dives over a two-week period.  The majority of those dives also occurred once the fish was estimated to be off the southeastern coast of DR, where the continental shelf habitat protrudes into the southern portion of the Mona Passage from Isla Saona.

The majority of those dives also occurred once the fish was estimated to be off the southeastern coast of DR, where the continental shelf habitat protrudes into the southern portion of the Mona Passage from Isla Saona.  For the remainder of the track while the fish was south of La Romana, crepuscular and night-time diving behaviors were extensive but rarely exceeded 100 meters like the dives observed off southwestern PR.

During the 57-day monitoring period, the bull experienced three full and two new moon phases.  Depth use during these periods did not show a pattern or trend.  Depth use during the full moon phases varied from deep during the first phase, shallow during the second, and back to deep during the third.  During the new moon phases, diving behavior was shallow during the first phase but deep during the second phase.  In terms of patterns or trends observed over the period, both night and the presence of extensive shelf habitat, which likely affect differences in foraging habits for prey, appeared to be drive changes in the vertical movements of this animal.

Another remarkable facet of this dolphinfish tracking event, as well as others that our program has logged around Puerto Rico, is the collaboration of the parties involved to help deploy tags as well as retrieve the tag that was the focus of this article.  The tag was retrieved through the help and assistance of Chris Whitley and Rick Alvarez, anglers who have extensive fishing experience in the Dominican Republic, as well as Oscar Paredes, Harbor Master at Marina Casa de Campo, who contacted fishermen in the local artisanal fishing co-op to locate the tag, and then helped ship it to our HQ.   This event also would not have occurred without the assistance of Captain Duran, mate Rodriquez, and photographer Dooley.  Over the past decade, six different captains and fishing teams have helped deploy satellite transmitters around the island, with the most recent being Captain Alexis and Sein Lopez of Aguadilla whom helped deploy a PSAT on a 34” bull on April 21^st, 2021.  A special thanks to everyone involved in the deployment of satellite tags on dolphinfish in Puerto Rico.  It is simply amazing how this event and the study of this species have brought together so many people on the island for the vital purpose to better understand and manage the most landed pelagic species on the island.

St. Croix to the Dominican Republic

Captain Colt Cook and angler Duncan Wright aboard Hook n Cook tagged and released a 20″ dolphin north of St. Croix in the southwestern portion of the Anegada Passage on August 3rd, 2020. On September 23rd, 2020, artisanal fishermen Alido Baez of Bayahibe, Dominican Republic, recaptured Hook n Cook’s fish aboard La Fiera, which had grown 5″. This is the 11th within-region Caribbean Sea conventional recovery and first from north of St. Croix to south of Saona Island, DR, spanning the entire USVI/PR continental shelf corridor to the southwestern edge of the Mona Passage. When combined with the other recoveries reported south of PR and DR since 2011, the average movement rate is 8.93 miles per day. In the image to the left the numbers represent days at liberty for 7 of the 11 recoveries. The only other recovery generated from the Anegada Passage was tagged and released aboard World Class Anglers by Captain Josh Slayton and was recaptured in the northwestern portion of the Mona Passage by Captain Matthew Bierley, showing that fish can move through the Mona Passage from the Caribbean Sea toward the Tropical Atlantic.

Straight-line distance between tag and recapture sites = 257.58 miles; Straight-line movement rate = 5.05 miles per day; Days at liberty = 51; Growth rate = .098″/day or .68″/week.

Merten, W.B., Appeldoorn, R.S., Hammond, D.L. 2016. Movement dynamics of dolphinfish (Coryphaena hippurus) in the northeastern Caribbean Sea: Evidence of seasonal re-entry into domestic and international fisheries throughout the western central Atlantic. 175, 24-34. Click Here for the PDF