Below this map are articles that cover tag and recapture activity, satellite tag deployments, and research findings from our work in the Eastern Tropical Pacific (ETP) Ocean.  At the bottom of this page is the first article published on our work in the ETP.  Everything in between are progress updates.  To help support our work make a tax-deductible donation at beyondourshores.org/donate or purchase a kit or shirt in our online shop dolphintagging.com/shop.

November 2023

This past month, our tagging program returned to Tropic Star Lodge (TSL), which is located in Pinas Bay, Panama, to outfit TSL’s fleet of Bertrams and additional vessels with conventional tagging equipment in order to continue to tag and release dolphinfish in conjunction with their annual billfish tournament.  While there, we worked with Captain Jesus, mate Aval, Jessica Harvey, and long-time volunteer tagging program participant Don Gates to deploy 10 satellite tags on dolphinfish ranging in size from 40″ to 56″ fork-length.  This work is funded by the Guy Harvey Foundation with additional support from sponsors and supporters of the Beyond Our Shores Foundation.

During the three and half days of nonstop fishing, tournament participants, as well as our vessel, Miss Costa Rica, managed to tag and release 178 dolphinfish with tags, beating our previous November record of 162 set back in 2018.  Since 2018, this effort at TSL has resulted in 1,081 conventionally tagged dolphinfish, which equates to 89% of all fish tagged for our program in the Eastern Tropical Pacific Ocean.  Our recent satellite tag deployments off TSL brings our program total to thirty-nine off Panama, with preliminary geolocation tracking data suggesting fish tend to move further to the south than west on short-time frames, spending more time in Colombian waters. Furthermore, once the tags separate from the fish, their drift patterns suggest a recirculation of surface waters, which supports the recurrence of individual dolphinfish throughout the year.  The recurrence of dolphinfish off Panama has also been observed by at least two dolphinfish reported with conventional tags after 391, and 403, days at liberty, tagged and recovered in nearly the same area.    What remains to be determined is how individuals move throughout the region on 3- and 6-month time frames, which is something we hope our recent tag deployments can help explain.  One of the major questions is how dolphinfish off Panama are connected to the largest dolphinfish fisheries in the region off Ecuador and Peru.  Last year, a satellite tag was recaptured by an angler based in Manta, Ecuador, but we were unable to acquire the tag or any additional capture information.  However, at least one confirmed recovery in Ecuador connected an individual dolphinfish tagged off Panama with coastal Ecuador in 63 days, which further emphasizes the need to observe how individuals move throughout the region over longer time frames.

Wildlife Computers (yellow) and Microwave Telemetry (red) satellite tags post-release drift paths.

Our 38th conventional recovery in the ETP occurred this past month on April 6th, 2023, in Panama (right image below).  The reporter received a small cash reward for the report.  Of all conventional recoveries acquired in the ETP to date, 34 have originated from tags deployed with the assistance of Tropic Star Lodge.  Even though this fish did not have a recorded size when released, it still provides a valuable movement record of a large bull dolphin off Panama that remained or revisited the area after nearly four months at large.  This is the third longest time at large for a fish tagged and recovered in Panama.  The other two were for dolphin recaptured in the same general area as this fish but after 391, and 403, days.

Our 39th conventional recovery in the Eastern Tropical Pacific Ocean (ETP) occurred on April 13th, 2023, off Mexico.  A commercial angler reported the fish and received a small cash reward for providing the capture details.  The bull was tagged and released by Mr. Paolo Coen and his friend Ivan on January 8th, 2023, fishing aboard A-Fin-Ity.  Mr. Coen reported a fork-length of 47″.  The reporter estimated the fish was 49″ when recovered.  One of the important aspects of this recovery is that it shows 2″ of growth after 95 days at liberty for an older fish.  This record will help improve our growth model for dolphinfish.  In addition, the fish was recovered along the continental shelf, which is similar to 3 of 4 satellite tag movements recently acquired from our work in Guatemala.  This latest recovery is our 3rd recovery within Mexico’s Pacific waters (left image below).

Our 37th conventional recovery in the Eastern Tropical Pacific Ocean (ETP) occurred on March 20th, 2023. A commercial angler named Victor reported the fish and received a small cash reward for providing the capture details. The fish weighed 10.4 kilograms (22.92 pounds) gutted. This fish was actually one of the last fish our team tagged fishing aboard Miss Texas on our epic research day off Tropic Star Lodge on November 19th, 2022 (click here to learn about that day). The bull was 44″ fork-length and, when based on length-weight measurements, likely weighed around 24-25 pounds. Based on seafood reports that we have gathered over the years for large fish, a large, gutted fish weighs 15-20% less than when sold whole. Therefore, at a gutted weight of 22.92 pounds, the whole weight was likely between 26.3 and 27.5 pounds, or a 45-46″ fish. The importance here is that this is a growth record for an older fish, which shows minimal changes in length but rather larger changes in weight (2-3 pounds) given the time at liberty (121 days). This latest recovery is our 4th recovery within Costa Rican waters.

In partnership with Casa Vieja Lodge based in Puerto San Jose, Escuintla, Guatemala, the Guy Harvey Foundation, and sponsors of the Dolphinfish Research Program, in mid-January 2023, six popup satellite archival transmitters were deployed off Guatemala on dorado ranging in size from 39″ to 43″ fork-length. In addition, vessel Release, Spindrift, and Makaira participated to tag and release 20 more dorado with conventional plastic dart tags. This effort marks the beginning of a concerted effort to better understand the movements and life history patterns of dorado off Guatemala and contributes to ongoing research being conducted in Panama, Ecuador, Costa Rica, Mexico, and within the Southern California Bight by the DRP.  More updates will be posted here soon.

By Dr. Wessley Merten – November 2022

During our recent expedition to Tropic Star Lodge, our tagging program deployed 162 conventional tags and 12 satellite tags.  This brings our TSL project total to 662 conventional tags and 31 satellite tags deployed.  In this article, we introduce our first geolocation track acquired from a 44″ bull tagged last November as well as an ongoing analysis of the differences in vertical habitat utilization between dolphinfish monitored in the Western Central Atlantic versus Eastern Tropical Pacific Ocean.  A special thanks goes out to the staff, captains, and mates of Tropic Star Lodge for their help with tagging and releasing 162 dolphinfish during the recent Annual Billfish Conservation tournament.

By Dr. Wessley Merten – March 2022

Last November marked the third field expedition for the Dolphinfish Research Program to Tropic Star Lodge to determine the horizontal and vertical movements of dolphinfish in the Eastern Tropical Pacific Ocean (ETP).  This field expedition and research is funded by the Guy Harvey Ocean Foundation.  During the most recent expedition, a total of 12 satellite tags were deployed, and we have received data from 9 so far with 2 more scheduled to report in May.  Since 2018, we have deployed 20 satellite tags on dolphinfish ranging in size from 36″ to 56″ fork-length.  When combined with TSL’s conventional tagging participation, which has amounted in the tag and release of 572 dolphinfish, of which 20 have been recaptured,  a preliminary dataset is taking shape that shows both fine scale and broad movements, habitat use, and fishery dynamics in this part of ETP.  Detailed updates on the progress of our research and program expansion in the ETP are available on this webpage.  A special thanks goes out to the entire TSL staff as well as the captains and mates for their help in making this effort possible!

By Dr. Wessley Merten – January 2022

A special thanks goes out to the Sustainable Fisheries Partnership (SFP) and MARTEC in Costa Rica for providing the funds for our tagging program to expand our tagging operations to Quepos, Costa Rica, this past month.  We distributed over 400 tags to local charter and recreational anglers based out of Marina Pez Vela and we are happy to report that the tags are starting to be put to good use.  Check out our video report (click here) which documents our recent trip down to Quepos, CR, to initiate this work.

By Dr. Wessley Merten – November 2021

Between the Western Central Atlantic Ocean (WCA), where our tagging program has been active since 2002, and the Eastern Pacific Ocean (EPO), where our program expanded with funding provided by the Guy Harvey Ocean Foundation three years ago, there are stark contrasts in oceanography, environmental variability, and pelagic habitat.  Last year, with field work based out of Tropic Star Lodge, we began to investigate how adult male and female dolphinfish vertical movement patterns off Panama compare to data collected on dolphinfish in the WCA since 2005. Many factors, including the productivity of surface waters, patterns of upwelling, the presence and absence of shallow oxygen minimum layers and differences in temperature, ocean currents, and the existence of holopelagic algae may influence differences in how adult dolphinfish behave between these two oceans.  All are observations that have never been concurrently documented for this species. Important to better describing the ecological niche that dolphinfish occupy and how vertical movement constraints or strategies could expose fish to differing rates of fishing mortality between these oceans, results can aid fishery managers in better predicting how dolphinfish may be exposed to different fishing gear types based on the prevailing oceanographic and environmental conditions. Using a thread-through satellite tag method, we acquired a 26-day and 30-day (full interval) record for a 39″ bull and 45″ cow, respectively, last November. The fish were caught aboard Miss Puerto Rico and Miss South Africa. They were tagged and released on two consecutive days during last year’s tagging trip approximately 20 miles west-southwest of TSL. While this work is certainly exciting on the water (see highlights from last November’s tagging trip in the video below), data analysis

Return Migrants and Satellite Tags Surface

By Dr. Wessley Merten – March 2020

In November 2018, the Beyond Our Shores Foundation (BOSF) began work to expand the Dolphinfish Research Program (DRP) to the Tropic Star Lodge

(TSL) in southwestern Panama.  This work continues today and is funded in part by the Guy Harvey Ocean Foundation (GHOF).  Through mid-March 2020, a total of 500 dolphin have been tagged and released by 21 vessels and approximately 154 anglers.  This effort has led to the recovery of 14 dolphinfish in the Eastern Pacific Ocean (EPO) and the deployment of eight pop-up satellite archival transmitters.  We recently received three recaptures reported by Captain Fernando Brias of Dios Primero, an artisanal fishermen based out of San Miguel Bay, that provided the first evidence of annual residents in Panama.  In a recent longline set, three fish had tags, and of those, two were fish that were tagged and released by Miss Puerto Rico and Miss England off Piñas Bay, Panama, in January 2019.

FIGURE 1 – QUANTITATIVE (LEFT) AND QUALITATIVE (RIGHT) MOVEMENT DYNAMICS OF DOLPHINFISH IN THE EASTERN TROPICAL PACIFIC OCEAN.  NUMBERS INDICATE DAYS AT LIBERTY.  TWO DOLPHINFISH WERE RECENTLY RECOVERED OVER PANAMA’S CONTINENTAL SHELF AFTER 391 AND 403 DAYS AT LIBERTY, THE FIRST TWO EXAMPLES OF ANNUAL RESIDENTS IN PANAMA.  IN ADDITION, RECENT SATELLITE TAG DEPLOYMENTS (BLUE ARROWS) REVEALED LARGE SOUTHERLY MOVEMENTS INTO COLUMBIAN WATERS IN 26 AND 30 DAYS.  TSL=TROPIC STAR LODGE; CO=COLUMBIA; PA=PANAMA; HS=HIGH SEAS; PT=PLAYA TAMBOR, COSTA RICA; PA=PUNTA ARENAS, COSTA RICA; GC=GULF OF CHIRIQUI.

While we do not know whether these fish remained in Panamanian waters for their entire time at liberty (resident substock?), these events could be the first evidence of annual return migrants to the region.  The question then becomes, where did they go?  Of the other conventional recoveries obtained, four were fish that were recaptured west-northwest of Panama.  As for satellite tag deployments, recent movements showed west-southwest to nearly southerly dispersals into Columbian waters.  After only 15 months of research funded by the Guy Harvey Ocean Foundation, we are beginning to acquire fascinating examples of the movements and life history patterns of dolphinfish in the EPO.  Stay tuned for our next update that will examine the vertical movement strategy of the bull and cow that moved south into Columbian waters.

FIGURE 2 – QUANTITATIVE MOVEMENT DYNAMICS OF DOLPHINFISH OFF PIÑAS BAY, PANAMA. NUMBERS INDICATE DAYS AT LIBERTY. THE UNLABELED RED OVAL IN THE CLUSTER OF YELLOW OVALS (RELEASES) WAS A FISH RECAPTURED AFTER 56 DAYS AT LIBERTY. BLUE= SATELLITE TAG MOVEMENTS; RED= CONVENTIONAL MOVEMENTS. A COMMA INDICATES MULTIPLE FISH RECAPTURED IN A LONGLINE SET.

First Year of Research Complete

By Dr. Wessley Merten – December 2019

It has been a year since the Dolphinfish Research Program expanded to the Tropic Star Lodge located in Pinas Bay, Panama. Recently, with support from the Guy Harvey Ocean Foundation and the Guy Harvey Research Institute, we embarked on our second research expedition to continue working with the Captains, mates, and visiting anglers at TSL to implement a robust tagging program in their waters. Below are some updates regarding our progress to date.

Total reported releases from 11.24.2018 to 11.24.2019: 447
# of Outings with reported releases: 101
Average size tagged: 30.96″ through 11.24.19
Largest fish tagged: 59″ (Record: Mr. Steve Roden)
Smallest fish tagged: 15″ (Record: Captain Fidel)
Most tagged in a single outing: 21 – Miss South Africa 11.27.18
PSAT movements: 6 records acquired – total monitoring time 33.69 days Longest single record 12.29 days.

Conventional Recaptures: 8 with a 1.8% recapture rate
Maximum conventional tag days at liberty = 96
Longest conventional tag movement = 796 mi. WNW caught by VZ purse seiner (Tagged by Miss Skandia) (oceanic and coastal stock mixing) (see article below)
Longest satellite tag movement = 168 mi W pop-off after 13 days
Maximum days at liberty for return migrant off Pinas Bay = 56

A total of 9 vessels at TSL have had fish recaptured or helped with a PSAT deployment.

Major Dolphin Recovery in the Eastern Pacific Ocean –

By Dr. Wessley Merten – September 2019

For a species as important as dolphin to so many fishing sectors in the Atlantic Ocean, one would think that we would know the status of the health of the population in the region.  Unfortunately, neither the National Oceanic and Atmospheric Administration (NOAA) nor any of the international fisheries management agencies in the Atlantic (e.g., International Commission for the Conservation of Atlantic Tunas (ICCAT) or Caribbean Regional Fisheries Mechanism (CRFM)) have made it a priority to conduct a modern stock assessment on the species.  The only modern stock assessment on dolphin was conducted by the Inter-American Tropical Tuna Commission (IATTC) which we reported about in our May 2018 newsletter.  Tropic Star Lodge (TSL).  This research is one component of GHOF’s

Eastern Tropical Pacific Seascape (ETPS) project which is a partnership between GHOF, the Guy Harvey Research Institute, Nova Southeastern University and TSL.  The objective of the ETPS project is to tag and collect migratory data from 3 species of billfish (sailfish, blue and black marlin) in the Pacific Ocean in order to shed light on the differences between the habitat use of the 3 species.  In addition, the project aims to collect migratory data on sharks, rooster fish, and dolphinfish.  In terms of dolphinfish and our involvement in the ETPS project, through the end of August 2019, a total of 381 dolphin have been tagged and released, of which 9 have been recovered.  Our most recent recovery reported by Pablo Luis Suarez and Gastelum Zuñiga Mario Francisco (Figure 1 – above) shows that large individuals of the purported resident coastal sub-stock in Panama can mix with the oceanic sub-stock in the high seas.  This is the first quantified evidence of these dynamics.  Mr. Suarez and Mr. Francisco caught the fish aboard a Venezuelan flagged purse seiner M/N Taurus-1 while fishing in the high seas of the EPO.  M/N Taurus-1 was targeting tuna when the dolphin was caught.  In addition to acknowledging Mr. Suarez and Mr. Francisco for reporting the recovery, we would like to thank IATTC and Marlon Roman in particular for sending us the tag that was recovered on the fish.  We would also like to congratulate Captain Mosquera of Miss Skandia of the Tropic Star Lodge for tagging and releasing this bull in January 2019.  For more information on other movements recorded to date (Figure – article below) offshore TSL, in the Gulf of Panama, or along the continental shelf break from northwestern Panama to Costa Rica, click here to read a brief but detailed article.  To help the DRP send kits to anglers from southern California to Manta, Ecuador, and to expand throughout the eastern tropical Pacific Ocean consider making a donation today.  Click here to donate to DRP expansion in the Pacific.

Tropic Star Lodge Dolphinfish Research Program Update –

By Dr. Wessley Merten – February 2019

Expansion to the Tropic Star Lodge –

By Dr. Wessley Merten – December 2018

Built in 1963, the Tropic Star Lodge has a rich history and exemplary reputation as one of the best fishing destinations in the world.   The Tropic Star Lodge has provided the ultimate experience for offshore and inshore fishermen for more than 50 years and is very active in fisheries conservation work.  The Tropic Star Lodge was not only the first fishing resort in Panama to begin releasing all roosterfish and cubera snapper but it also adopted the use of circle hooks in the early 90s to improve the survival rates of released fish. Tropic Star Lodge, along with many leaders in Panama, have been responsible for establishing a 20-mile non-commercial fishing zone around Piñas Bay and also a decree that protects all billfish and roosterfish from commercial harvest.    Click here to read a document prepared by Panama’s Authority in Aquatic Resources.  Many of the topics discussed and progress explained in that document are the result of years of work with many different entities including the Tropic Star Lodge.

The tremendous conservation efforts outlined in the document above are fantastic achievements for Panama and we are pleased to announce that through the support of the Tropic Star Lodge, Guy Harvey Research Institute at NOVA Southeastern University, Guy Harvey Ocean Foundation, and captains, mates, local and visiting fishermen in Panama, the Dolphinfish Research Program successfully expanded to southwest Panama during the 2018 Tropic Star Billfish Tournament.  We outfitted the lodge’s fleet of Bertrams, along with 4 private boats, with more than 1100 conventional tags and we began our satellite tracking and fishing fleet work.   We are extremely excited to get the Tropic Star Lodge involved in the Dolphinfish Research Program to help advance ocean conservation and our knowledge of the life history, movements, population dynamics of dolphinfish in Panama.