Green list of activity providers

for the Manta Ray Experience in Kona, Hawaii

– Rules & Reasons –


The intent of the Green List of Activity Providers is to inform and educate the public so that the manta rays are protected from any adverse consequences of human interaction. Manta Ray Tour Operator Standards AKA Industry Standards for Kona, Hawaii were created in 2013 so that tour operators have specific marine life friendly and safe operational guidelines, but unfortunately not all activity providers have chosen to follow them. The Green List of Activity Providers identifies those tour operators whose method of operation is consistent with the spirit and intent of the industry standards.


The Green List of activity providers is maintained by Hawaii Ocean Watch, a 501(c)(3) non-profit organization.


The Green List committee is responsible for maintaining and updating the Green List. The committee consists of 5-7 people (local captains, dive masters, snorkel guides, managers) who work or have worked and experienced the complex environment of the manta activity. The committee examines the submitted field reports to determine compliance to Standards and will decide by a majority vote if a company will be green-listed. If there is a repetition of non-compliance, the vote will determine if a company should be taken off or does not appear on the Green List.


Field representatives who are working in the manta tourism industry will submit data pursuant to a form to HOW’s Green List committee from each location.  Submissions can be made online, by text, or in writing. The pre-requisite to become a field representative is: a.) been working at the manta sites for more than 6 months and b.) are present at one manta site at least two nights per week. Public data submission is also welcome and will be considered.


For a boat operator to attain “Green List” status, it must adhere to the 6 main Green List criteria which are based on the Industry Standards.

  1. No Touching
  2. No Freediving
  3. No Hull Lighting
  4. No Propeller / No Live-Boating
  5. No Fragmentation
  6. No Anchor


The 6 main Green List criteria are outlined below and organized by:

  1. the criteria,
  2. the reason
  3. the rule


The green list is an ongoing reviewable designation that is updated monthly and companies can either be added or removed based on their adherence to the criterion the 30/31 days prior.


4 of the 6 main Green List criteria have a built in 10% tolerance to protect boat operators from unforeseen circumstances beyond their control and “perfect storms” that may happen e.g. medical emergencies, gear problems, equalization problems, emergency ascents, wind shift, uncooperative participants, people from shore or drama.


·   No Hull Lighting 10%
·   No Touching
·   No Free Diving
·   No Anchor on Coral ·   No Propeller Use
·   No Fragmentation


HOW Criteria: No Touching

CRITERIA #1: No Touching the Manta Rays

REASON: Manta rays are covered with a slime coating which protects them from parasites and infection.  When manta rays come in contact with another object, the coating is mechanically removed.  It has also been documented that unexpected contact “spooks” the rays causing them to leave the area, or collide with objects and people.

RULE: Guests from each company must be briefed on the “No Touch” policy and why.  If touching is observed the guides must remind the guests of the rule.  If the participant continues to touch they should be asked to board the vessel as this may constitute a safety hazard to others.

If a company is observed having individuals touching the rays in excess of 10% of their charters they will be removed from the green list.

HOW Criteria: No Free Diving

CRITERIA #2: No Free Diving Into Midwater

REASON: With 150-200+ snorkelers and 30-40 divers participating in the activity at once, it is imperative that the midwater section be left “open” for the manta rays.  If snorkelers are freediving or divers are coming up into midwater, the activity would be the chaos we are trying to prevent.  A manta ray can weigh upwards of 1500 lbs (680kg) and if startled, it might swim into a person causing serious harm. Further, inexperienced free divers sometimes ascend into people or objects above them.

RULE: Companies who have guests in mid water for extended periods of time in excess of 10% of their charters will be removed from the Green List.

HOW Criteria: No Hull Lighting

CRITERIA #3: No Underwater Hull Lighting – or illumination of water around the ladders, propellers, and rudders.

REASON: The manta rays have learned that lights attract plankton.  They have also learned to get very close to those lights to get the maximum amount of plankton.  Historically, those lights have been either held by divers, snorkelers, or in light crates on the bottom of the ocean. The rays anticipate that when they skim across the top of lights that nothing will harm them. The use of lights on the hull of the boat puts the lights behind and next to the ladders, rudders, and propellers.  The rays swim into the boat’s hardware and are injured.  It has been documented that several strikes to both rudders and propellers have caused serious injuries to the manta rays.

RULE: Any use of hull lighting while within 200 yards of the manta site will result in removal from the Green List.

HOW Criteria: No Propeller

CRITERIA #4: No Propeller Usage and Live Boating During Activity.

REASON:  Propeller usage and live boating is dangerous because it creates the potential for propeller strikes to humans and manta rays.

RULE: Any boat driving through the designated viewing area, i.e. over divers seated at the campfire, or within 10 meters of a snorkel board viewing mantas in excess of 10% of their charters will be removed from the green list.

HOW Criteria: No Fragmentation

CRITERIA #5: No Fragmentation

– Fragmenting is defined as leading the mantas away from the central viewing area (“campfire”).

– The best case scenario for the manta experience is 25-90 minutes after sunset. See appendix.


  1. Greater Good – Since the 1990s the activity has been centralized so that no group missed out on seeing the manta rays (campfire method). One light column = one place for the mantas to congregate = most amount of manta rays for the maximum amount of time. Fragmentation can create 2-10+ different light sources spread out over 100 square meters.  It often results in groups not seeing and experiencing the manta rays at all.
  2. Fragmentation causes mantas to navigate through a “minefield” of mooring and anchor lines. – As opposed to having one location to go to, the rays swim through the manta site searching for the most plankton. Manta rays are unable to see what is directly in front of them so anchor lines are “invisible” to them and harm them.
  3. Accounting for Divers – Plankton is usually more abundant over the reef. When snorkel groups fragment away from the rubble bottom where the campfire is located, they often force other dive companies to relocate onto the reef to view the rays. Moving groups of divers going in different directions increases the anxiety level of the divers and increases the likelihood of someone following the wrong group. Again, all light sources should be concentrated in one place for the rays to feed so that everyone will see them.
  4. Changing manta behavior – The Kona manta industry rates the plankton amount on a scale of 0-5. 0 being no plankton, 5 being plankton so thick it blocks light. Plankton concentration in natural current lines is approx. a 2.5 or 3 on a good day.  When snorkel rafts continuously fragment over the reef where plankton is in a higher concentration, the rays are learning that there will always be a level 3 or 4 plankton to feed on. We are noticing a change in the behavior of the mantas at the campfire. In 2005-2009 a level 2 would have held the rays all night.  Today we are seeing that they aren’t staying at the campfire unless it is 2.5 or 3.
  5. Injuring mantas due to overcrowding in shallow waters. – Snorkel rafts who conduct their activities in 15 feet or less of depth are often attracting larger numbers of rays due to the abundance of plankton. A larger number of mantas don’t have the room to maneuver and back flip so they are running into the bottom and/or urchins, getting scraped, as well as running into each other.

RULE for Makako Bay:

All snorkel rafts must disconnect from vessel without delay and go to the central viewing area after getting all guests situated in the water.

The campfire area is defined as the area within a 10 meter diameter of the campfire ring being used by the divers located in the rubble/sand chute in Makako Bay.

There are 2 campfire rings that can be used:

  1. “The Regular Campfire”: The ring of rocks at 35ft where the divers normally set up their dive.
  2. “The Deep Campfire”: This is a ring of rocks at 45ft where the rubble meets the sand. This campfire is used as a back-up to the regular campfire on nights with moderate to severe ground swell.

Due to documented manta entanglement and boat hardware collisions, no snorkel rafts can be attached to its vessel with the lights on for an extended period of time. Lights should be turned on when guests start to enter the water and should be turned off when guests begin to exit the water at the end of the experience.

If at 45 minutes after sunset the plankton is not building and/or the rays are not staying, then snorkel and dive groups may disperse and go on a night reef tour. If companies choose to put participants into the water prior to sunset, they are still required to go to the campfire until 45 minutes after sunset. Operators must show that they first go to the campfire and promote the best case scenario.

“FINE PRINT” to address the situation that many companies have the bests intention not to fragment, but are forced to leave the campfire because the rays are feeding with groups that purposely fragment: these groups will not be penalized if they stay at the campfire for at least 20 minutes before relocating to assure that their guests still get a manta show. Companies who stay at the fragmentation location after the initial offender has left will also be considered fragmenting.

Most important is that a company shows their willingness and intent to work towards the best case scenario.

RULE for Keauhou:

All snorkel rafts must disconnect from vessel without delay and go to the central viewing area after getting all guests situated in the water. Due to documented manta entanglement and boat hardware collisions, no snorkel rafts can be attached to its vessel with the lights on for an extended period of time. Lights should be turned on when guests start to enter the water and should be turned off when guests begin to exit the water at the end of the experience.

Due to no divers being present at Keauhou the central viewing area may shift from night to night but will always be located between/close to the 4 existing moorings, but never in or near the boat channel for Keauhou harbor.

The central viewing area is also defined as the location where the majority of the groups are seeing manta rays. To reiterate, the purpose of a central viewing area is to have the maximum amount of mantas for the maximum amount of time.

The first snorkel board to have a manta stay and barrel roll will be the initial board.  Groups entering into the water afterwards will join the area where the mantas have already congregated.

Companies who fragment more than 10% of their charters will be removed from the Green List.

HOW Criteria: No Anchor on Coral

CRITERIA #6: No Anchor Dropping on Coral.

REASON: Damage to coral is against State law. It is common knowledge that a healthy reef is imperative for a healthy ocean and vital for a sustainable manta ray industry.  Damage caused to the reef from anchors is careless and totally unnecessary.
At Makako Bay there are currently 7 underwater mooring balls for boats to tie to and a huge sand area to drop an anchor in.  In Keauhou there are 4 mooring balls for boats to tie to and several small places to carefully drop anchor if conditions are right.

RULE: Companies dropping anchor on coral or in an area where there is high probability of coral, without putting a spotter in the water, will be removed from the Green List.

(Obviously) companies who drop anchor because of a stalled engine or eminent danger will not be penalized unless it becomes a reoccurring problem.

Appendix: Best Case scenario for the Manta Ray Experience in Kona, Hawaii

Times for entering the water are based on data collected between 1998-2012 with the goal of creating an environment that results in the most consistent manta sightings.

Ideal Campfire Setup