Bermuda’s Endemic Fundulus Killifish

Bermuda has two endemic species of brackish water killifish, from the genus Fundulus. In 1998, when I was the President of the Bermuda Fry-Angle Aquarium Society, I began researching these killies, as there was very little known about them within the aquarium hobby. My research led me to write three articles about these fish – two for our society’s newsletter and one for a publication of the Bermuda Zoological Society. I am reproducing those articles in this post, so that they can be accessed in one location (and not be lost when I close down my old website).

Since writing my articles, a significant amount of work and research has been undertaken in Bermuda by Mark Outerbridge. I am also including a link to a paper that Mark wrote (along with Samia Sarkis).

Here are some photos that I took of the Bermuda Fundulus. They are not the best quality, I’m afraid, but they give an idea of what the fish looks like.

FOUR a.m. FORAY(written in 1998)

For some time now, we have been discussing collecting the Bermudian endemic killifish, Fundulus bermudae.  The killies are all located in the protected nature reserves which meant that permission had to be sought from the Department of Parks before any collecting could take place.  I sent off a letter seeking permission and then set about learning what I could about the fish.  A visit to the library at the Bermuda Aquarium, Museum and Zoo (BAMZ) revealed that Bermuda’s Fundulus have been the subject of a number of scientific studies in the past, and that they are part of a current project.

Fundulus bermudae has been around for quite some time and was first described in 1874 by Gunther.  The “Field Book of Shore Fishes of Bermuda” by William Beebe and John Tee-Van, published in 1933, states that the fish was abundant in the brackish pools and ponds of the time.  Papers have been written about the species in 1952, 1957, 1967 and 1980.  In 1988, Able and Felley proposed that there is a second species – Fundulus relictus.  They report that relictus is only known from the type locality – Lover’s Lake, a 1.2 acre pond at Ferry Reach.  The major differences between relictus and bermudae involve lower fin-ray and gill-raker counts.  To the casual observer, they appear identical.

A 1986 newsletter of the Bermuda Audubon Society reported that Fundulus bermudae was to be found at Bartram’s Pond, Mullet Bay.  Dr. David Wingate, Government Conservation Officer, reveals that Bartrams Pond was stocked following a trans-location of specimens from Lovers Lake.  The original pond was used as a dump or land-fill around the time of the second world war.  The Audubon Society has since acquired the land and re-constructed a pond.

In 1993, the Department of Agriculture and Fisheries Report listed F. bermudae as being present in Trott’s Pond and Mangrove Lake.  The Lover’s Lake population was listed as F. relictus, as per the finding of Able and Felley some years previous.  The report went on to say that new populations had been found at Evans Pond and the small ponds of West Walsingham, on the Wilkinson Trust land.  It was suggested that these populations were endemic.

In 1994, the Bermuda Audubon Society newsletter reported that Fundulus had been located in Warwick Pond.

An ongoing project involving Bruce Collette and others at Tulane University is likely to determine whether we do, in fact, have two or more species of Fundulus in Bermuda.  Collette and his team will be conducting morphological and molecular systematics  using material collected over the years by Collette (Sterrer).

Bruce Collette lists four distinct populations of Fundulus:  Lover’s Lake, Mangrove Lake, Walsingham Pond and Evans Pond.  The status of the Evans Pond population was unclear, as he had only seen one specimen and had not collected from that location (Sterrer).

I tried to obtain slides of F. bermudae but discovered that there were none available at BAMZ.  Dr. Wolfgang Sterrer was very helpful and contacted Bruce Collette.  He had slides in Washington, DC, and agreed to send some.  Dr. Sterrer pointed out that the line drawing of F. bermudae in his book was actually wrong (the only error in the book – just my luck).  The only picture that I could find was in Beebe and Tee-Van’s book (see illustration above).

Dr. Wingate has been surveying Bermuda’s ponds for the last 10 years.  He was able to give a detailed account of the existing populations.  Original populations exist in Lovers Lake, Mangrove Lake, Trott’s Pond, Walsingham West Pond, Warwick Pond and Evans Pond.  Additionally, specimens have been trans-located from some of these ponds in order to establish additional populations.  The Lovers Lake specimens went to nearby Bartram’s Pond and specimens from Walsingham West went to Blue Hole Park.  Artificial ponds, one salt and one fresh, were created on Nonsuch Island.  The saltwater pond was stocked from Trott’s Pond and the freshwater pond was stocked from Mangrove Lake.  The move to freshwater necessitated a two-week period of acclimatisation but the population adapted well and is thriving.

Most of Bermuda’s ponds are brackish, if not pure seawater.  Warwick Pond, however, is close to being freshwater.  Dr. Wingate therefore believes that the Warwick Pond population is likely to be the most distinct, if the various populations are found to be different species.

In the afternoon of Friday, 28th August, 1998, I met with Dr. Wingate to discuss this issue.  He granted us permission to collect Fundulus, but suggested that we only collect from Bartram’s Pond.  There are a number of concerns.  As research is still ongoing to determine whether or not each pond holds a distinct species, it is imperative that specimens from one location are not transferred to another.  If all captive specimens come from the same pond, control should prove easier.  Secondly, Bartram’s Pond is not one of the original populations, having been stocked itself from Lover’s Lake.  It was therefore deemed to be a better option for collecting for the aquarium hobby.

Dr. Wingate asked for the assistance of members of our society to stock the recently created pond at Paget Marsh.  Extensive restoration work has recently taken place in Paget and a new freshwater pond has been created.  Dr. Wingate wishes to stock the pond with Fundulus and the nearest population is at Warwick Pond.  Warwick Pond is rapidly silting up, so it makes sense to trans-locate some of its population to safeguard it against possible extinction.  Of course, I informed Dr. Wingate that we would be happy to assist in any way that we could.  The problem, for many of our members, was that he wanted to attempt the trans-location at 4am that Sunday (30th August).  I made some telephone calls but a combination of short notice and the proposed collecting time meant that only Nyon Steede and myself were available.

At 4am that Sunday morning, Nyon and I joined Dr. Wingate at the Warwick Pond.  Dr. Wingate had suggested that 4am would be an ideal time to catch the Fundulus.  He explained that the oxygen levels in the pond would be depleted, due to there being no photosynthesis of plants during darkness.  This, he suggested, would cause the Fundulus to rise to the surface for air.  We would then “spotlight” them with a flashlight and easily net them.  That was the theory.  We tried a number of spots around the pond and merrily “spotlighted” away.  I even waded into the muddy, and smelly, back side of the pond.  We were swarmed by Gambusia holbrooki but didn’t spot a single Fundulus.  We were up early and there was no sense in calling it a day so soon.  Neither Nyon or I had ever seen Fundulus in the wild, so Dr. Wingate suggested that we take a drive to Bartram’s Pond.

We made stops at a pond on Belmont Golf Course and Blue Hole Park.  Dr. Wingate had seen Fundulus teeming in Blue Hole during the day-time but then, in the dark of night with a flashlight, we only caught fleeting glimpses of a couple.  When we caught a Fundulus in our light, it made for cover.  So much for being attracted to the light.  We had learned the hard way that Fundulus are unlikely to be caught in this manner.

We made our way to Bartram’s Pond.  The idea had been to use the Warwick Pond as a test for our collecting methods.  We would then plan an outing for the members to collect at Bartram’s.  Circumstances change, and here we were, up early with collecting equipment at the suggested collecting site.  By the time we reached the edge of the pond, daylight was beginning to creep in.  As with the other locations, “spotlighting” failed to attract Fundulus.  As it got lighter, we began to see a number of Fundulus, swimming amongst the Gambusia.  There were small numbers of them, just one or two at a time.  They were also just out of reach of my collecting net.  Believing that we would not collect any that day, we began to discuss returning on another day with a seine net.  Almost ready to pack up and leave, I agreed to get into the pond in an effort to reach the few Fundulus that were swimming out of reach.

I stepped down into the pond and was about knee deep in water.  The bottom of the pond was quite firm and nowhere near the quagmire of Warwick Pond.  There was some detritus on the bottom that was stirred up by my standing in it.  There I stood, with my dip-net submerged in front of me.  I waited for a Fundulus to swim over the net and then quickly lifted it.  I caught some and others swam quickly away.  After catching a couple of loner Fundulus, I glanced down near to my feet.  To my surprise, I was surrounded by Fundulus.  They were obviously attracted by the stirred up debris from the bottom of the pond and were swimming through it, looking for food.  Collecting then became easy, like shooting the proverbial fish in a barrel.  In no time I had nine Fundulus in the bucket.  We checked for males and discovered that there were at least two.  We didn’t want to collect more.  This collection was not planned and we were unsure whether our members would have tanks ready for new fish.  It was now 7.30 am.  Our 4am foray had lasted 3 ½ hours.

When I got the bucket of Fundulus home, I checked the sexes and found that I had 3 males and 6 females – three trios.  I soon contacted our two most active fish breeders, Jeremy Lodge and Chris Roy, who were keen and ready to take a trio each.  I took a trio myself.  The water from Bartram’s Pond was tested and the specific gravity / salinity was found to be the same as seawater.

I took a number of slide photographs of the Fundulus that day, both male and female.  Copies have been supplied to BAMZ and I have the others.

Fundulus bermudae is closely related to Fundulus heteroclitus, which can be found along the eastern coast of the United States.  Dr. Wingate has found a dead female bermudae on Nonsuch Island that was at least 5 inches long.  Heteroclitus have been listed as reaching 7 inches in length.  We can be certain that, as far as killifish are concerned, F. bermudae is on the large side.  The specimens that I collected were about 2 inches in length, the larger specimens being the females.  They are a pleasant olive green in colour with a pattern of vertical bars.  The male has a black spot, surrounded by a white edge, at the rear of his dorsal.

I went down to the ocean and obtained some fresh seawater that I placed in a 5 gallon tank.  The tank is equipped with a sponge filter.  I added two floating mops and one sinking mop to the tank and then added the trio of Fundulus.  The following day I offered regular flake food that was immediately gobbled up.  It is apparent that these Fundulus are very easy to maintain in captivity.  They spawned in the first week of captivity, preferring the floating mops, very close to the surface of the water.  I  picked 8 eggs from the mops and placed them in a jar.

About two weeks later I again located eggs in the floating mops and was able to pick 9.  I considered the possibility that the parents were gobbling up eggs after they had been laid so I decided to check the mops early in the morning.  For the next two days I was able to pick 8-9 eggs a day, all of them being found in the floating mops, close to the surface of the water.  These initial observations suggest that the fish deposit small numbers of eggs over a period of days.  Regular examination of the mops is therefore necessary to gather the most eggs.  The eggs have not yet hatched but hatching is expected to occur after about 3 weeks, judging on reports concerning heteroclitus.

With three trios of wild fish in captivity, I expect that we will be able to adequately supply any demand for the fish with F1 fry (first generation from wild parents).  I will make the fish available free of charge.  This will avoid the need to collect any further wild fish.  There is already interest from the United States and the US hobbyists may be supplied with eggs, which are easier to mail than live fish.

Those members who still wish to try collecting wild Fundulus will still get their chance.  Dr. Wingate still needs to trans-locate some of the Warwick Pond population to Paget Pond.  Hopefully, we will be able to accomplish this in daylight hours, in the near future.  It will not be as simple as collecting in Bartram’s Pond.  I have since returned to Warwick Pond and baited an area with fish food.  I did not see any Fundulus, but  I am hopeful that the fish still exists in Warwick Pond.

It is very important that Bermuda’s hobbyists take every step to protect our natural resources.  Even offspring from our captive Fundulus should not be released into our ponds – unless specifically directed by Dr. Wingate.  Once in our tanks, the fish might be exposed to diseases that do not exist in the ponds.  Releasing fish back into the wild might also release diseases or bacteria that could harm the environment.  Dr. Wingate and the Parks Department have shown trust in us and we must ensure that we prove worthy of it.

COLLECTING CLOSE TO HOMEA Return Visit to Bartram’s Pond(written in 1999)

Members may recall a previous article entitled “Four am Foray” in which I recounted an early morning expedition to collect our native killifish – Fundulus bermudae. That trip resulted in the collection of 9 fish that were subsequently bred by some of our members.

Recently, we have been contacted by a number of US killifish fanciers, who have read the article on the web-site and are keen to obtain some F. bermudae. In an effort to boost the captive population (and the availability of eggs for export) we decided to conduct a second collecting trip.

Four of us set out for Bartram’s Pond, in St. Georges, on Sunday 27th June, 1999, My intrepid co-collectors were Chris Roy, Jeremy Lodge, and Darin Mosley (with son Tristan). Having learned a valuable lesson on the “four am foray” we planned this trip for a much more reasonable time of 9.00 am. We figured that this was late enough not to cause sleep deprivation and early enough to avoid the heat of the midday sun. It had only taken a few minutes to catch the fish on the first trip, so I assumed that we wouldn’t be at the pond for any more than a half-hour. Wrong!

I was the only one of our group to have been to Bartram’s Pond before, so I led the way through the trees and bushes until we found ourselves at the pond. As with most of the ponds in Bermuda, Bartram’s Pond is a nature reserve. Collecting fish from the ponds is illegal without specific prior permission from Dr. Wingate at the Parks Department. We had been given permission to collect from this pond only.

On my first visit to the pond last year, I found the bottom of the pond to be quite firm with only a slight covering of silt. When I stepped down into the pond on this occasion, I was surprised to find myself sinking mid-calf into the silt. This visit was to prove quite different to the first. I tried collecting in the same spot, and manner, as I had on the previous visit but found nothing but Gambusia (mosquito fish). After wading out a little further I was able, with a bit of perseverance, to catch two Fundulus. Things were not looking good.

Meanwhile, Jeremy had moved further along the bank to check out other spots. He began calling out to us that he could see huge blue killies from his position. The Fundulus that we had caught before were not huge and they certainly were not blue. With a certain degree of scepticism, I got out of the water and walked around to Jeremy’s position to see his “Bermuda Blue Killie”. I had to eat my words. The killies there were indeed “huge” in comparison to those we had seen previously. As they moved through the water, the upper body did appear to be a light blue, with a bright yellow underbody (males).

Jeremy got into the water but the Fundulus appeared to be just out of reach. Quoting the motto of the British S.A.S. – “Who Dares, Wins”, I eased past Jeremy and out into the deeper water. I moved out until the water was past my waist. The silt from the bottom was stirred up so much that I couldn’t see any fish at all. I stood still for a few minutes and, eventually, the silt began to settle and I began to see these gorgeous fish schooling in front of me. They appeared to be 4-5 inches long and flashed the bright yellow and pale blue colours as they passed. Whilst the water was up past my waist, my feet were deep in silt. A huge group of snails took a distinct liking to my left leg and attached themselves to it. It was not a comfortable feeling and on a number of occasions I tried to brush them off. It was as futile as King Canute ordering the waves to stop. I left them to munch on my shin after a while.

As the silt settled, the fish began to come closer and, before long, they were within reach. I found that if I remained motionless, with my net submerged in front of me, I was able to catch the large Fundulus. I had to wait patiently until a group of them swam over my submerged net. At the right time, I quickly lifted the net and snagged a few prize specimens. I soon mastered the trick of balancing a bucket of water in my left hand whilst netting the fish with my right hand. Successful nettings were interspersed with periods of waiting, as the schooling killies moved around to other parts of the pond. Eventually, I had quite a number of fish in the bucket, and I was tiring of being breakfast for a horde of snails.

None of the others had managed to catch any Fundulus – but I had the advantage of a larger net that was obviously needed. This was proven once I handed the net to Darin, as he too was soon catching Fundulus.

We had undertaken to supply the Bermuda Aquarium with a quantity of the Fundulus for display and each of us also wanted to take some home. We got more water from the pond and began to count out males and females into various buckets. We were happy that we had collected sufficient fish for all of our needs and we decided to wrap things up. By the time we left the pond it was almost 11.30am and the sun was getting pretty hot.

On the way back, we delivered about 20 Fundulus to the Aquarium, where they were placed in quarantine. Hopefully, they will be on display soon. By midday, I had my trio of Fundulus in a tank at home.

I tested the water from Bartram’s Pond and found the salinity to be 35 ppt (or Specific Gravity 1.026). The pH was 7.0 and the Total Alkalinity was 180 ppm (the latter two measured using Mardel Saltwater test strips). I obtained a bucket of ocean water and found that to have a salinity of 37 ppt (or Specific Gravity 1.027). So, as you can see, the water in the pond is very close to being ocean water. I am presently keeping my trio in seawater but they can be gradually acclimatised to freshwater.

Whilst the fish had appeared to be between 4-5 inches in the pond, once they were in the tank and a tape measure could be used, I determined that the larger male was about 3 inches total length, and the females were 2 1/2 inches. The females are a drab olive colour with the vertical stripe pattern. The males have a wonderfully bright yellow lower half to the body and fins but the pale blue upper body is not visible in the tank. Perhaps correct lighting and a larger, decorated, tank may bring out the natural colours.

My trio have quickly taken to flake food and the spawning mops. Within the first week of captivity, I collected over 20 eggs from the mops and they will be sent overseas. If anyone is interested in acquiring some of these fish, please contact Chris, Jeremy, Darin or myself and we will be glad to assist.

Fundulus bermudaeThe Rodney Dangerfield of Bermuda’s Endemics

Written in 2003 for “Critter Talk”, the publication of the Bermuda Zoological Society, and intended for a non-fishkeeping readership.

I have to say that Fundulus bermudae is the Rodney Dangerfield of Bermuda’s endemic species, because it gets no respect!  Ask a Bermudian to name an endemic species and they may answer Bermuda Cedar – Juniperus bermudiana, the Cahow (Bermuda Petrel) – Pterodroma cahow, or the Skink (Bermuda Rock Lizard) – Eumeces longirostris.   I would be surprised if anyone mentioned Fundulus bermudae.  Even if you narrowed the question, and asked what fish inhabit Bermuda’s ponds, the answer you would get would most likely be the Guppy (more correctly, the Mosquitofish – Gambusia holbrooki) which is an introduced species.  So, what is this little known or respected Bermuda endemic?

Fundulus bermudae is a killifish, a type of fish often referred to as a killie.  It inhabits many of Bermuda’s ponds but seems to be little known by Bermuda’s human residents.  Ironically, there appears to be greater interest in the fish overseas than there does locally.  I have received requests for F. bermudae eggs from as far afield as Sweden.

Fundulus bermudae has been around for quite some time and was first described in 1874 by Gunther.  A variety of scientific studies have been conducted over the years, yet the fish remains largely unknown to the general public.  Some studies have suggested that there are more than one species of endemic Fundulus in Bermuda, but further studies are required to finally determine how many species we have. DNA samples should provide a definitive answer and plans are underway to have such samples collected and tested.

There are very few pictures of F. bermudae available – no respect!  When I first attempted to obtain slides of F. bermudae, I discovered that there were none available at BAMZ.  Dr. Sterrer pointed out that the line drawing of F. bermudae in his book was actually wrong (the only error in the book).  The only picture that I could find was an illustration in Beebe and Tee-Van’s 1933 ‘Field Book of Shore Fishes of Bermuda’.  I have since been able to photograph the fish myself.

Dr. Wingate has been surveying Bermuda’s ponds for over a decade.  He is able to give a detailed account of the existing populations.  Original populations exist in Lovers Lake, Mangrove Lake, Trott’s Pond, Walsingham West Pond, Warwick Pond and Evans Pond.  Additionally, specimens have been trans-located from some of these ponds in order to establish additional populations.  The Lovers Lake specimens went to nearby Bartram’s Pond and specimens from Walsingham West went to Blue Hole Park.  Artificial ponds, one salt and one fresh, were created on Nonsuch Island.  The saltwater pond was stocked from Trott’s Pond and the freshwater pond was stocked from Mangrove Lake.  The move to freshwater necessitated a two-week period of acclimatisation, but the population adapted well and is thriving.

Most of Bermuda’s ponds are brackish, if not pure seawater.  Warwick Pond, however, is close to being freshwater.  Dr. Wingate therefore believes that the Warwick Pond population is likely to be the most distinct, if the various populations are found to be different species.  However, attempts to catch Fundulus at Warwick Pond have been unsuccessful and the status of that population is unknown.  It is hoped that some Warwick Pond Fundulus can be caught and relocated to the recently created pond at Paget Marsh.

It is important to note that we still do not know whether we have multiple species, or sub-species, of killifish in Bermuda.  It is possible that each of the primary ponds could hold distinct species.  Until this is determined by the DNA testing, it is crucial that fish from different ponds are not mixed.

Fundulus bermudae is closely related to Fundulus heteroclitus, which can be found along the eastern coast of the United States.  Specimens that I have collected were about 3  inches in length but some have been found that reached 5 inches in length. They flash bright yellow and pale blue colours when viewed in the ponds.  When they are first captured, the males have a pale blue upper body with bright yellow flanks and fins and are very attractive. The blue colouration fades once in captivity.  The females are a pleasant olive green in colour with a pattern of vertical bars.  The male has a black spot, surrounded by a white edge, at the rear of his dorsal fin.

Collecting fish from the ponds is illegal without specific prior permission from the Parks Department. It is very important that we take every step possible to protect our natural resources.  Even offspring from captive Fundulus should not be released into our ponds, to ensure that no diseases or bacteria are released that could harm the environment.  Members of the Bermuda Fry-Angle Aquarium Society have collected Fundulus previously, but only from Bartram’s Pond.  By collecting from this one location, we know that specimens in the aquarium hobby come from a single population.

These Fundulus are easy to maintain in captivity.  They spawn readily, preferring to deposit their eggs in floating mops made of nylon yarn. They place the eggs on the mops very close to the surface of the water.  The eggs are hard enough that they can be picked by hand from the mops and placed into another container to hatch. 

So, the next time that you think of Bermuda’s endemic species, I hope that you remember our Fundulus killies.  Keep an eye out for them the next time you visit one of the ponds that they inhabit and you may be rewarded by their blue and yellow colours as they dash past.

SUBSEQUENT RESEARCH BY MARK OUTERBRIDGE

Mark Outerbridge (Bermuda Department of Conservation Services) has undertaken extensive research on Bermuda’s Fundulus populations, since I wrote the above articles. His research has included scientific fish counts for each of the ponds that hold Fundulus, as well as taking fin clippings from each of the populations. These fin clippings were sent for DNA analysis, in the hope that such work could definitively answer the question of how many distinct species of Fundulus exist in Bermuda.

The DNA work has not been completed. However, so far, it has been determined that the populations in Lover’s Lake and Bartram’s Pond (which was stocked from Lover’s Lake) are indeed the species Fundulus relictus. At this time, the other populations are considered to be Fundulus bermudae, albeit that the possibility still exists of additional species or sub-species. As was posited back in 1998, the population in Warwick Pond is still considered to have the potential to be a distinct species, along with Evans Pond. They also hold the most at-risk populations.

As the Fundulus are not marine species, they are not protected by the Fisheries (Protected Species) Act 1972. However, both F. bermudae and F. relictus are considered to be endangered species as per IUCN criteria and are therefore protected by the Protected Species Act 2003. That act makes it an offence to catch, possess, or export these species.

The following chart shows the species identity and estimated populations in each pond, as per the work conducted by Mark in 2007.

Much more information can be found in the “Recovery Plan for Killifish in Bermuda (Fundulus bermuda, Fundulus relictus)”, by Mark Outerbridge and Samia Sarkis, published in 2011. The research paper can be accessed using this link. The Recovery Plan also includes the following two photographs of Bermuda’s Fundulus (female on left and male on right).

3 Comments

  1. Thank you for the most interesting & informative articles on the Bermuda Killifish. I had totally forgotten about their existence & reading your pieces reminded me once again. Your writings are greatly appreciated.

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