One of the very best things about diving in the same area for years is learning about the lives of the individual animals who live there. To make this possible, the animal must have features or markings that make it identifiable as an individual, so that it can be recognized over and over again over time. These features can include a missing fin or tail, damaged part of the body, or a distinct color pattern.
It also helps if the animal is rare, because that causes us to notice it in the first place! Last month one such rare fish appeared on the wreck of the St. Anthony off of Maui. A Longfin Batfish (Platax teira) was observed by Autum Hill swimming around inside the cabin on Sept. 7.
This species is not considered native to Hawaii, so initially this individual was thought to be an aquarium release (home aquarium keepers often buy fish as juveniles, but if the fish get too big for the tank, regrettably people sometimes release them into the ocean). However, according to www.hawaiisfishes.com at least two have been reported off Oahu, one off the Big Island and another off nearby Johnston Atoll (Kalama Atoll) only 860 miles to the southwest, so it is possible that an occasional larval individual drifts here naturally from elsewhere in the Pacific or arrives as a juvenile under floating debris.
What made last month’s sighting at the St. Anthony wreck of even more interest is that there have been several other sightings of a Longfin Batfish on the St. Anthony as far back as Dec. 2003. Here’s what we know about the 2003 individual:
On Dec. 15, 2003, Bo Lusher and Andy Schwanke were diving in 85 feet of water off Pu‘u ola‘i, Maui at a site called the 85 ft. Pinnacle, and saw the first Longfin Batfish we had ever seen in Hawaiian waters. INCREDIBLY, the next day a Longfin Batfish was seen on the St. Anthony wreck about 3.5 miles away. Because Andy had taken a photo of it on the 14th we were able to compare the color pattern and tears in the fins and, as you can see in the photos below, it was the same fish! He or she had swum a distance of over 3.5 miles in one day.
Initially he stayed inside the cabin of the wreck, but after a couple days he began swimming around the wreck in the open. He stayed for a few weeks during which time our divers were treated to seeing a fish not normally found in Hawaii. But then one day he was no longer there.
Then in January of 2005 David Fleetham photographed a Longfin Batfish on the St. Anthony again! We were thrilled to be able to use his photos for comparison and to learn that this was the same fish – 1 year older! The cuts in the dorsal fin had healed, but the color pattern could still be used for identification. He resided there again for awhile and one day was gone.
Two other Longfin Batfish sightings and photos from the St. Anthony in March of 2011 and now in September of this year (2016) allow us to compare photos again. Is this the visiting batfish from previous years?
As you can see above, this is not easy to discern. At a glance, it hardly looks like the same individual. Every camera and lens renders a difference in color and aspect ratio, and the fish is almost never in exactly the same position in relation to the camera. However, if you have a few days to spend comparing the photos I think you will agree that it is the same individual! A 13-year visitor to the wreck.
Making identification potentially trickier is the fact that this species of fish apparently sometimes changes color in parts of his body. In the photo on the right, notice the large black areas on part of the dorsal fin, back of body, caudal peduncle and anal fin. David Fleetham was inside the cabin of the wreck and was within a foot of this fish when photographing him with a wide angle lens. Perhaps the fish was stressed in the confines of the cabin with a diver so close and was exhibiting stress coloration, because this black area does not appear in the photo that he took right before this or in any of the other photos of this individual from other sightings.
Judging by the tears and bites in the fins, life is not the easiest wherever he normally resides. In fact, Dr. Jack Randall says, “It is surprising that this species survives, because it is so exposed most of the time, far from shelter, and because it is not a fast swimmer.”
And now, as of Oct. 18, he is gone again, after being last sighted by Rachel Domingo on Oct. 16. His five week stay on the wreck went all too quickly. What other home(s) does this fish have? What makes him return to the St. Anthony? Surely there is an innate urge to find a mate – a hopeless exercise in Hawaii where they are not normally found. Could that be the impetus for his repeated visits to the wreck?
We will never know why he returns, but thanks to observant divers and underwater photography we at least know who this fish is. Knowing that this is the same individual again and again is like knowing a little secret about the life of one fish in the sea.
Written by Pauline Fiene. Photos as credited. Thanks to Andy Schwanke, Benja Iglesis, David Fleetham and Rachel Domingo for photo usage.