SharkTagger.org

Home
United States
Kaneohe, HI
SharkTagger.org

Preserving shark population integrity through innovative investigations

SharkTagger is a research program focused on the use of advanced telemetry technologies to elucidate shark movement behavior and habitat requirements. Our research objectives are geared towards filling data gaps identified by regional fishery management organizations as critical to engineering effective conservation strategies for shark populations impacted by commercial fisheries.

01/13/2026

Happy New Year everyone! We took some time off social media over the break to reflect on 2025 & our goals for 2026!

Some highlights of 2025:

* We pulled our acoustic receiver array from the FADs around Oahu & Big Island & downloaded silky & oceanic whitetip detection data to wrap up the acoustic telemetry component of the HCTP after 6 years of monitoring! Huge mahalo to for assisting us!

* We conducted shark depredation mitigation trials in Kona by testing three new technologies on the market; Fishtek Sharkguard, RPLEX, and Sharkstopper. We found the electric deterrents to be more effective than the acoustic deterrent. This pilot study is a great starting point to address this extremely important issue for Hawaii small-boat fishers.

* We published the manuscript “Using photo identification to assess demographics & fishery interactions of oceanic whitetip sharks in the main Hawaiian Islands”. A huge mahalo to everyone who submits their oceanic whitetip shark imagery, without your continued collaboration none of this would be possible! (Link in bio for anyone who wants access to the paper)

*We continued amassing photo ID data. We have now uniquely identified 459 individual oceanic whitetip sharks based on their dorsal fin patterns around the main Hawaiian Islands (Kona; n = 439, Oahu; n = 16, Molokai; n = 1, Maui; n = 1, Kau’ai; n = 2). Of these 289 are female, 135 are male & 35 are unidentified s*x.

There is SO much to look forward to in 2026:

* Presenting the results of our depredation trials at the Western Pacific Regional Fishery Management Council (WestPac) Shark Depredation workshop in Honolulu in February & at the WestPac Council Meeting later on in the year.

* And finally analyzing and writing up the depredation study and oceanic whitetip and silky shark FAD association around Hawaii!!

As always we are so grateful to the community that has supported the work to understand the drivers of shark-fishery interactions as we continue to search for solutions.

🤙🏾🦈

12/17/2025

The second device we tested during our trials was the SharkGuard™. This device emits a 50 volt pulsed electric current when in seawater to disrupt the sharks sensory system (the ampullae of Lorenzini around its nose) and leverage sharks’ sensitivity to electric fields.

Summary:

* We found these devices very easy to use, they are small (8 inches) and could be rigged in line or easily attached to a ‘traveller rig’ that we slid down the line when a fish was caught (see pic 3).

* The Sharkguard is depth rated to 500 m meaning it still works at depths the small scale fishers are finding tuna around the Big Island

* It takes one AA battery that lasts for 8-hrs at a time, and only turns on when wet.

* The device appeared to have a deterrent effect, we noted small behavioral reactions to the device on baited lines and during our fishing trials we observed other boats in the area getting sharked when we were not.

But we cannot be 100% certain of the deterrent effect - because we had no shark depredation events when we caught fish - we switched between the deterrent and a control device (device turned off) and landed whole fish when using both devices.

* The good news is that having the device on the line did not impact catch rates. And we landed many whole fish with the device on the line.

*In fact our only depredation event was by a dolphin and it ate our fish before we were able to get the device down the line.

🦈

12/12/2025

One of the devices we tested last week was the RPELX ‘deep-drop’ shark deterrent™

This is an electrical deterrent of 200 volts that attaches to the fishing line. The RPELX is depth rated to 100 m and is useful for fishing in shallower environments or trolling. The device has a 3m electromagnetic field to deter sharks.

Summary::

The RPELX had a really strong deterrent effect on oceanic whitetips at the surface (swipe to see videos). The sharks showed an obvious reaction and turned away multiple times (but did come back each time).

This device works best in shallow (< 100 m) environments, so is best to slide down the line while trolling or if a shark is depredating in the top 100 m.

However, it was tricky to find an optimal configuration for the RPELX and fishing with make dogs at the FADs. Because the device was stopped at the bag, so couldn’t slide down to be within 3ft of the hook.

12/08/2025

What a week - Deterrent trials are finished! We didn’t have much time to post as we went ...so here is a summary and we’ll do some more posts this week about each individual deterrent.

We trialled three shark deterrent devices. Two electric devices that are available on the market - (200V) and Sharkguard (50V) and one acoustic device (in its testing phase that emits the sounds of an Orca hunting)- the SharkStopper.

In summary the electronic devices showed more promising deterrent effects than the acoustic device. Oceanic whitetips appeared to react negatively to both electric deterrents which emit a pulse of electric current when a shark comes within a 3ft of the hook.

Fishing was pretty slow but we managed to catch at least 16 whole fish including; ahi (yellowfin and bigeye over 50lbs), tombo (albacore tuna), aku (skipjack) and shibi (small tunas) .

We didn’t have any instances of depredation where a shark took a bite of the fish from the line. But we lost a few at depth. We also had a some problems with dolphins stealing our bait from the line.

This makes it difficult to determine if the deterrent devices were effective, because we were able to land fish with the devices switched on and off! But we were fishing next to fishers getting sharked and we weren’t, so there may be some promise in these devices!

Trials will continue over the next month so we can increase our sample size!

Huge mahalo to Jason & Radon on Kalohokai and & on for taking us out and helping us conduct these trials!

Stay tuned for more detailed updates this week 🤙🏾

11/30/2025

Shark depredation mitigation trials are about to begin this week in Kona!

We are testing three new deterrents on the market:
1) the Fishtek Sharkguard
2) RPELX and the
3) SharkStopper.

Kona fishers - where have you had the most depredation issues lately? Comment below or message us and we will go to those locations first!

We will keep you guys posted about our progress 🤙🏾

11/04/2025

A couple of days ago we received this imagery from & of an oceanic whitetip shark interaction in really shallow waters just off the coast of Maui between Po’olenalena and Palauea..You can see from the video its swimming over a shallow reef!

The female shark was estimated to be carrying ~15ft of trailing gear too. The large fish under her throat is a remora.

It is extremely unusual for oceanic whitetips to be using shallow waters, as they are usually found over deep oceanic / pelagic habitats much further offshore.

We think that this individual may be in distress and that’s why its hanging around so close to shore.

For incidental interactions with this species the best handling recommendations across management agencies require the removal of as much fishing line as possible, leaving less than 3 feet, when safe to do so.

Seems like this skinny little lady got a bit unlucky - if anyone sees her please let us know! We are interested in tracking her fate!

Mahalo for the 📸 &

10/28/2025

Bycatch in global tropical tuna purse seine fisheries represents a significant source of mortality for manta and devil rays (mobulids), which are globally threatened. Previous studies have shown that mortality of mobulids captured in purse seine fisheries can be significantly reduced when handling times on deck are less than 3 minutes. However, interventions must be operationally feasible, and safe for human operators if they are to be successfully implemented at a large scale.

A new study by Cronin et al. is a brilliant example of how strong collaboration and knowledge sharing between researchers and fishers enabled the design and creation of a manta sorting grid, a bycatch reduction device (BRD) for mobulids captured in purse seine operations. The sorting grid consists of a rigid frame, typically made of stainless steel, with cords or ropes arranged in a grid (swipe to see pictures of it in action and is designed to eliminate the need for direct manual handling, protect sensitive body parts of mobulids, and streamline the release process so they are back in the water faster. It also allows tuna to pass through while retaining mobulids on top.

The authors state that ‘fishers’ practical knowledge and hands-on experience with gear and fishing operations provided valuable insights that helped shape the feasibility, design, testing, and refinement of this device.

Link to the paper is in our stories!

Speaking of which, our long history of working with fishers in the search for depredation mitigation options has revealed some partially effective strategies. But we are happy to report that we have received some additional funding to test a few new shark deterrent devices that have recently hit the market. We plan to take you along for the ride as the project develops and we start testing as soon as the federal government resumes and can disperse the funding!

10/15/2025

We have another confirmed re-sight of an oceanic whitetip shark!

Last month, on 1 September 2025, & encountered this 6ft male oceanic whitetip off Kona. He was cruising with another oceanic whitetip and a pod of pilot and melon-headed whales and was clean of fishing gear.

Then, just over a month later & encountered the same individual off Kona again hanging around with a pod of pilot whales and still clean of fishing gear.

Oceanic whitetip sharks are often found around Kona associating with pods of pilot whales. Overall, about 20% of our photo submissions of oceanic whitetip encounters are recorded in association with pilot whales. Normally, these types of associations result in a benefit for one of the species either through shelter and decreased predation risk or an increase in feeding opportunities

Pilot whales are extremely efficient at detecting food, and their distribution links closely with their primary food source, squid which is also a component of the diet of oceanic whitetips. Pilot whales also share their catch within their pods and family groups, so it’s possible that this allowed OCS to benefit from scraps that are not consumed.

Mahalo to everyone who submits their interaction imagery to us, we really appreciate it!

Awesome pics snapped by:

📸

03/20/2025

🦈 NEW RE-SIGHT 🦈

This female oceanic whitetip was first sighted at FAD C on 1-Feb-2022 by .kayleigh @ . She hung around FAD C for the next week, and the team sighted her twice more on the 6th and 9th of February and then .boyd.underwater of Seadog Productions photographed her on the 14th February 2022.

Fishers often report oceanic whitetips sitting on the FADs and these consistent resights corroborate these observations. Our acoustic data also show similar residency behaviors to some extent, although we find a lot of individual variability in FAD residency times. Some individuals spend a few hours at a FAD while others hang around for days or weeks. Then disappear for extended periods of time before being redetected again.

Awesomely, 10 months later on 17 December 2022 this lady was spotted again back at FAD VV by .kayleigh & team.

Fast forward a bit over two years later and this same gal was encountered back at FAD VV on 14 Feb 2025, by & !

It’s so amazing to see she is still looking super healthy and completely clean of fishing gear! Hopefully she stays smart and avoids fishing interactions!

Mahalo as always to everyone who submits their imagery!

📸 .kayleigh .boyd.underwater

03/14/2025

Hawai’i is home to so many marine protected species. Protected species are those that are exempt from harm under various federal or state legislation and in Hawai’i these include; all marine mammals, i.e. Hawaiian monk seals, and many species of whales and dolphins, as well as sea turtles, manta rays, and oceanic whitetip sharks.

We have teamed up with the Division of Aquatic Resources (DAR) Protected Species Program (PSP), who are helping us manage and maintain our oceanic whitetip dorsal fin catalog. The PSP is responsible for conserving, protecting, and enhancing the protected marine animal species found in Hawaiian waters. They do this through public outreach and education, invasive predator management, pono (responsible) fishing advocacy, animal and habitat monitoring, marine debris removal, stranding response, and more.

Outreach and education are so important for everyone who lives in and visits Hawai’i to get more information on Hawai’i’s protected species. We love seeing how far and wide these outreach materials can be found around the islands. This is great for us, as it expands our outreach capacity for our oceanic whitetip shark dorsal fin catalog too!

The PSP team is working on getting species ID guides at all harbors, fishing stores, dive stores, charter, fishing, and dive boat operations across the Hawaiian islands, to help ocean-goers with species identification and where to report their sightings.

If you are a shop owner, fisher, boat owner / operators and would like to any outreach materials, please reach out to our friends at

03/04/2025

Oceanic whitetip shark photo submissions are always less frequent for us over the winter months. It’s difficult for us to tease apart whether this is because there are fewer sharks present? Or do fewer interactions occur because tourist boats have shifted focus to whale watching tours? Or perhaps they aren’t going out as much because of the weather and / or tourist numbers are lower in the winter?

Last week from submitted the second oceanic whitetip interactions (for our database) of 2025! The team encountered 3 beautiful oceanic whitetips with pilot whales at VV buoy on Feb 14, 2025.

Slide 2 shows one shark with evidence of a fishery interaction with the hook imbedded in its left pec fin, and well over a body length of trailing line attached.

We are always interested to hear from fishers and in-water folks about your oceanic whitetip shark interactions.

Fishers - have you had problems with shark interactions lately? Are there fish around?

In-water folks - have your interactions with oceanic whitetips been more or less frequent over the winter?

Interestingly, our tag data tends to show lots of individual variability in oceanic whitetip movements . Our satellite tag data show individuals making broad scale movements away from the islands, with some returning. While our acoustic data show almost year-round detections (see last slide).

Let us know! And if you have had any interactions lately and if you have pictures - please submit!

Mahalo as always to everyone who submits their imagery to us! We really appreciate you.

Epic 📸 by

02/27/2025

Detecting and monitoring retained and bycatch species caught in the Hawaii longline fishery is one of the main goals of our NOAA Fisheries colleagues Jenny and Josh. Their Electronic Monitoring (EM) team has been making awesome progress lately on their Artificial Intelligence (AI) models and excitingly, they have finally been able to add sharks as a new addition to the model!

Model performance metrics and testing of raw video footage through the algorithm demonstrates some great potential for the model, although some enhancements are needed to reduce false positives and missed sharks.

We are excited about EM paired with AI as a tool to monitor sharks incidentally caught by fishing vessels with the potential to expand coverage to fishing fleets with limited or no monitoring.

Address

Kaneohe, HI

Website

http://sharktagger.org/

Alerts

Be the first to know and let us send you an email when SharkTagger.org posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The Organization

Send a message to SharkTagger.org:

Shortcuts

Want your organization to be the top-listed Non Profit Organization in Kaneohe?