Cyprinodontiformes vivíparos e ovovivíparos
Livebearer Cyprinodontiformes
Artigos - O Ovovivíparo de Endler
Articles - Endler's Livebearer
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Cyprinodontiformes vivíparos e ovovivíparos Livebearer Cyprinodontiformes Artigos - O Ovovivíparo de Endler Articles - Endler's Livebearer |
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Endler's Livebearer Armando Pou - published at this website in June 2006 |
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Introduction
Right through this extraordinary occasion, Armando staggered me with the below message, as response to my request for publish an issue about this species. With the consent of the author it self, I have the honour to share this information considered by me as extremely significant and imperative to be familiar with Poecilia wingei. Thank you very much to Adrian and to Armando.
From : Pou, Armando Sent : Wednesday, June 1st 2006 20:10 Subject : Information on ELBs ( P. wingei ).
This is the basic collection information : Where “ Laguna de los Patos “ use to be ( in the late 1990’s ) there are now four basic bodies of water. Two on one side of a relatively new large road ( Autopista Sucre ) and two on the other. There is a shantytown on the edges of one of the lakes and untreated sewage flows into it. I found no fish life in this one ( at least none that I could readily see as I did not dip my nets in that mess). The second lake adjacent to it was polluted with fill and dump debris but had many “ Endler's livebearers “ ( Poecilia wingei ) in it. This body of water appeared void of any large fish predators and was 100% Endler from the samples I took. The third and fourth lakes were across the highway. Both had been stocked with Chichlids, one was in a clay mining compound, was void of shoreline vegetation and I found no Endlers or guppies to exist in it. The fourth lake contained Endlers along it's reed filled shore. Many displayed an unusually large amount of black pigmentation ( I called the lake “ Black Endler Pond “ in the Tropical Fish Hobbyist article ). The lakes periodically flood, in fact one floods out into “ Laguna Malagueña ” after heavy rains. “ Laguna Malagueña “ lies adjacent to the ocean on perimeter road ( La carretera perimetro que sigue la costa del mar ). At one time this body of water had both Endlers and Picta but since it now opens to the sea at high tide many of the Endlers have disappeared ( on one of my trips during the rainy season in the 90’s I had confused this laguna as being part of Laguna de los Patos ). There are also slow moving streams and ditches leaving three of the lakes at “ Laguna de los Patos “. The only place I actually saw guppies in Cumaná was away from these warmer, brackish, polluted waters. Like the Manzanares River, which was a good 15 degrees cooler than the Laguna, the water was much clearer and flowed well. There have been many discussions about Endler “ types “ in the hobby. I have included locations where these Endlers were collected. ( Actual collection data I found from old notes ) :
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1) Laguna De Los Patos North Lake – “ Double Sword Endler “, “ Black Chest Stripe “ ( Like original fish from the 70’s ), “ Snake Skin Endler “ ( Collected in March 2004, and 1998 )
Additionally, this is some of the information I provided to TFH in 2004.
Professor Endler explained that they were possibly a distinct Poecilia species closely related to the guppy, P. reticulata. His had been the last collection of this Poecilid. These fish collected in the 1970’s made it into the tropical fish trade where they have been given the name - Endler's livebearer or Endlers. He also informed me that Franklin F. Bond originally collected the same specie along with Poecilia reticulata in 1937 and that this collection of specimens was still at the University of Michigan Museum of Zoology, in a jar labelled Lebistes reticulatus. Dr Endler gave me some directions from memory to the lake where he had found these fish. The hunt was on ! In order to understand the origins and evolution of the Endler's Livebearer you have to become familiar with the early history of Cumaná. Cumaná was the first fortified European settlement on the mainland of the Americas. Cumaná Castle is a dense limestone fortress, which sits atop a ridge of this coastal city. From it, the Spanish Conquistadors were able to protect the two main riches that brought them there. The first being the pearl trade and the second being a vast salt mine. After years of exploitation, a great storm, or hurricane, hit Cumaná; the torrential runoff burst past the levy the Spaniards had built at the mouth of the mine and flooded it out. Several attempts were made to pump the water out of the mine. When these failed the mines were abandoned. This was the birth of Laguna de Los Patos. Over the centuries numerous earthquakes have occurred in this region. Many times these earthquakes destroyed the town and often diverted the path of the Manzanares River. I speculate that these seismic events coupled with the flooding and displacement of this river may have also played a role in establishing the fish fauna of the various lakes of this region. During my first trips to Cumaná I erroneously identified La Laguna Malagueña as Laguna de Los Patos. La Laguna Malagueña is more of a true lagoon or estuary whereas Laguna de Los Patos, while sometimes brackish, ( especially during the height of the dry season, specific density at surface : 0.008 ) is a lake. Both of these bodies of water and other smaller ponds and rock pits interconnect during the rainy season via a series of drainage ditches and run-off pipes as the timeless cycle of water makes its journey to the sea. Both Laguna de Los Patos and Laguna la Malagueña have been fragmented into several smaller components by road expansions and modern mining activities, which now extract clay and cement products. As we approached Laguna de Los Patos I grew tense with anticipation of what would lie there. My last trip was in December of 1998 and much had changed since that time. It was the height of the dry season and the heat was oppressive. The pungent smell of burning rubbish hung heavily in the air. As I walked towards the lake my worst fears were realized. The edges of Laguna de Los Patos had been filled in by building materials and rubbish. The sort of materials that would normally be found in a land fill, but here they were being used to form a foundation that eventually will be occupied by ranchos or shanty town dwellings common in the poorer outskirts of Venezuela. The four lakes that comprise Laguna de Los Patos are heavily polluted. The two lakes which now lie on the eastern side of a highway called Autopista Antonio Jose Sucre are somewhat cleaner than those that lie on the western part of the highway. The larger of the eastern two lakes is within the mining compound and has very scant vegetation remaining along its fringes. Additionally it has been stocked with Cichlids, which have effectively eradicated most of the Endlers. The smaller lake is easily accessible from the highway and contains a very interesting population of melanistic Endlers.One of these Endlers appeared nearly black from the surface but eluded every attempt I made to net it. I did collect some specimens from this nameless pond, or rock pit, which I dubbed black endler pond to differentiate it from the other nearby biotopes. Although there were also cichlids present, the edges of this deep pond had plenty of vegetation, which afforded the Endlers hiding places. Two larger lakes are found on the western side of the highway. The southern most of these is so heavily polluted with raw sewage and debris from a shantytown that sits on its southern shore that I could find no signs of fish life in it. The northern lake is now the last stronghold of the original endlers. Although also polluted and ranging from milky white to tan in colour, Endlers are very common here. Apparently this deep lake is so lacking in oxygen that no cichlids or other predatory fish survive here, allowing the Endlers to flourish near the surface. Unlike Professor Endler's observations, I did not see Poecilia reticulata present at these lakes and believe that guppies do not co-exist with Endlers in Cumaná. If they did they would almost certainly hybridize. I feel that it is here where the first Endlers began to appear perhaps over four hundred years ago when that great storm flooded out the mine. The founding population was probably made up of a few hardy and tolerant individual specimens that rapidly multiplied to fill the lake. This would make the Endlers only recently divergent from guppies and still in the process of evolving into a unique species. The lack of predators here has allowed the spectacular colours Endlers are known for to evolve, female preference being the selecting force or pressure rather than predation. I would like to return to this lake with the proper equipment to take salinity and water samples at different depths because I suspect that the specific gravity will increase with depth. From a water hyacinth choked drainage ditch leaving the northern lake of Laguna de Los Patos I pulled a small jewel - a single male specimen of the fabled black pectoraled Endlers. After exhaustively searching the other bodies of water and with several hundred Endlers collected, this was the only one with black pectoral fins. This characteristic is a recessive trait that Professor John Endler described as being present in 20% of the fish he collected in 1975. Somehow this black pectoral form of Endler has over time disappeared from the existing wild populations. There are other interesting morphs that occasionally pop up in wild populations of Endlers. Note the photograph with the female with black markings on the dorsal and extended dorsal rays. This specimen, along with the other female with the black spot on her side and the male with the black anal fins ( next to the gonopodium ), came from black Endler pond. I now made my way north towards the ocean and La Laguna Malagueña which sits on the landside of the perimeter road : Avenida Universidad. Compared to Laguna de Los Patos this estuary is fairly unpolluted and thriving. It is a fresh to brackish water estuary largely surrounded by Black Mangroves, Buttonwood, and several other coastal hardwoods. These trees were alive with small rookeries of scarlet ibis, egrets, heron’s cormorants and brown pelicans. On the ocean side of the laguna there is a finger channel or canal crossing under the beach side road. On my earlier trips to Cumaná in the late 90’s this channel was full of livebearers and other fresh water fish. In addition to Endlers I found P. picta, a molly species, Cichlids, what appeared to be a Rivulus killifish and numerous fiddler crabs. At that time this channel died a couple hundred yards from the ocean. On this trip the same channel laid open to the ocean during high tide. Now it only contains Cichlids and Picta. The water of the laguna itself ranged from a pea green colour to a silty red-gray. It was quite stagnant in areas, where a mucousy white film covers the surface. The bottom of the lagoon was mucky and rich in leaf detritus. The familiar smell of rotting seaside vegetation was everywhere. The area surrounding the lagoon was quite arid; red soils dominating the cliff side of the laguna and calcareous sand on the ocean side. Laguna la Malagueña is still largely fresh water during low tide, but I believe the salt content in it increases during high tide and that the salinity also increases to a lesser extent during the dry season. The water depth varies from a few centimeters to three or four meters, the largest portion being shallow flats. At one time there were as many as 15 to 20 basic types or forms of Endlers present at La Laguna Malagueña, with 7 or 8 forms being abundant. One of the attractive common types was the one established in the hobby from Dr. Endler's original collection in 1975. The orange and peacock strains now often seen in the hobby are descendants from my first collection in Laguna la Malagueña. I only managed to collect a couple of specimens of the orange form during this trip. They were all on the inland portion of the Laguna. The Endlers seem to have been negatively impacted by the channel's re-opening to the ocean. The P. pictas that exist in Laguna la Malagueña are very robust and large. An occasional male form exists which is completely orange with transverse black bars. All the male Pictas develop a spectacular dorsal fin when fully mature. Their dorsal fins are brilliant yellow with black spots and more rays than other populations I have seen in Trinidad and Brazil. These fish are roughly 1-1/2 times larger than typical Endler males with a stockier appearance. The differences between the Endler's Livebearer and P. reticulata are several. P. reticulata is highly variable, I've rarely collected two specimens of reticulata from the same location that exhibit similar makings or coloration, yet there exists a limited number of basic types of Endlers within these lakes. The double swords on the caudal fins and the dominance of orange, black and green colorations are a couple of the characteristics commonly found in most wild Endlers. None of my collections from elsewhere in northern Venezuela or Trinidad come close to the vividness and intensity of colour of the fish from these lakes. As if painted with watercolours the orange and black sometimes bleeds into the gonopodium and other fins, which are always clear in other wild guppy populations. Morphologically speaking Endlers also have a more angular appearance than reticulata, seeming almost bent at the dorsal and having a longer SL ( Standard Length ) to CFH ( Caudal Fin height ) ratio. This gives them a thinner more elongated appearance. The habitat of the two fish also varies. P. reticulata usually exists in flowing streams or waterways in which the water temperature averages in the mid to upper 70's F, while the water of these lakes was consistently in the low to mid 80's especially in the shallows. Additionally, I cannot stress enough the stagnant reduced biotopes in which Endlers seem to thrive. Finally, in my opinion, perhaps the trait that differentiates the Endlers most from guppies is the presence of what I believe to be very active melanophores. The black coloration exhibited by endler males fades when stressed and intensifies when displaying territorially or during courtship behavior. This characteristic is more reminiscent of Pictas than reticulata and is one I believe sets Endlers apart from reticulata. In 1998 I set up a series of 10 ten-gallon aquariums with 3-4 male Endlers to each female. The black coloration on the dominant male would intensify and the female showed a marked preference for this fish. At the time I did not quantify my results because it was very difficult to determine which male was mating more frequently with the female and differentiating which offspring belonged to which male would be practically impossible. When the dominant or alpha male was removed from the aquarium, within a day or two one of the other subordinate males' black coloration would intensify and it would become the new alpha male. This occurred in each and every tank. In 2001 I placed in each aquarium four Endler females with one Endler male and one male guppy from Trinidad. Without exception the females chose the Endler male with the intense black coloration. This year I introduced a variant to the same experiment. I have placed four female guppies from Trinidad in each tank along with one male Endler and one male Trinidad guppy. What I am finding is quite fascinating. It seems that the female guppies are choosing the male Endlers equally to the male guppies. These results are too preliminary and I am not truly satisfied with my observations, as both lines have been established for several years now and in my mind they are both domestic stocks. I am hoping in the future to be able to run the same experiment with completely wild caught fish. |
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Flame Tail
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Common Peacock
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Peacock Half Tux
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Center Peacock
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Solid Red Stripe Peacock
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White Pecock
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Red Chest
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Top Light Blue Sword
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Orange Spoted
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Center Monocle
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Snake Chest
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Double Red Stripe
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Dr. Endler had mentioned to me that he was unable to hybridize P. reticulata and Endlers, and felt that this cross would produce sterile offspring. I have not found this to be the case. I believe that initially, wild caught fish are difficult to hybridise with other species because they are imprinted with specific cues that signal to them what members of their own species should look like, behave like and maybe even smell like. Once a domestic or aquarium population is established however, the offspring of these fish are more easily coaxed into hybridising. One method I have used involves raising single specimens of different species together. Of course the species have to at least belong to the same genus. Livebearing fish are particularly easy to hybridise. In the past I have successfully hybridised P. picta and Endlers as well as P. reticulata and Endlers. The latter cross producing completely fertile offspring while the former cross varied in fertility rates. Although the P. picta X Endler was less fertile initially ( some pairs never producing offspring ), I was able to establish a continuous line through colony breeding. I guess the question still remains : Are Endlers a local race of the common guppy or are they in fact a distinct species ? In light of some of the information I have uncovered, the argument can be made that since man played a role in their origins, they should not be considered a species. However, species have always influenced other species. In fact, it is a cornerstone in the theory of evolution. Predator-prey relationships, symbiosis, parasitism, even domestication have all led to new species. What about hybridisation ? I believe Endler's livebearers, Poecilia reticulata, Poecilia picta and Poecilia parae are all closely related species. This is similar to the relationship between the platys and swordtails of Mexico and Central America. Many members of the Xiphophorus family will also hybridise and produce fertile offspring but are considered distinct species. Whether Endlers are ever categorized as a separate species, subspecies, or are found just to be a local variant of P. reticulata, they certainly do inhabit unique biotopes and the same forces which brought about their evolution will undoubtedly one day bring their extinction. Venezuela is an incredible country with beautiful people and eco-variety which ranges from the majestic Andes to the evergreen pantanals and from the Orinoco's Amazon to the coastal scrubland which is this region of Sucre. However, before you gather your buckets and collecting nets know that this is also a country on the verge of civil war and its government is well on its way to a totalitarian dictatorship ala Cuba. Make sure you acquire the necessary ornamental fish permits from INAPESCA and that you have arranged to export your fish. As my plane left Cumaná I noticed several other smaller ponds and lakes around this region which I did not get a chance to explore. These may also yield interesting Poecilids. |
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Author's foot note : Recently “ Endler's Livebearer “ has been re-classified as a new species by Dr. Fred Poeser's new taxon paper ( Poecilia wingei ). This publication is an excellent source of information !!! My only disagreement is a casual statement Dr. Poeser made that the fish from Laguna de los Patos were probably due to human introductions or “ aquarium releases “. This impoverished area of Venezuela has few “ Aquarium hobbiest “, and certainly not in the 1930's when the fish were first discovered by Franklin F. Bond. This region of South America is constantly under dynamic upheavals, both storm related and geologic. I believe that it is more plausible that these fish found their way into the Laguna de los Patos through one of these events.
Contributions to Zoology 74: 97–115. |
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