Chichencanaab pupfish species, an update

Authors: Arcadio Valdés-González

Year: 2012 (xliv)

Abstract

The Chichencanaab lagoon is situated at the center of the Yucatan Peninsula, Northwest of Quintana Roo, constituted by a set of consecutive lakes in seven to 12 sections in a row flowing north to south of up to 30 km long and one km with of swamp at its best. It is the habitat of 7 Cyprinodon species with recent speciation, perhaps 8,000 years (Strecker, 2006). The cracking of the species has been suggested as of habitat isolation and/or niche partitioning process by specialization to different diets intakes. Recent global warming, together with touristic industry and urban development has made tremendous impact on the stability of the system and now threatens to vanish all species richness. The original purpose of this project was to gain understanding on the difficulties faced when several attempts were made to establish these fish under captivity, having lost all of them on several occasions, always due to micobacterial infection. The idea was to search for information on: are all these fish endangered, does these fish are infected from its origin or while in transit to the lab? For that reason we programmed a visit on the 15th- 20th of March 2011, with SEMARNAT permit No. SGPA/DGVS/00915/11. Dizuche and La Presumida Municipalities were visited at eight locations, 1) Extremo Norte, dried; 2) Buluckax, stagnant lagoon, low level, dried native mangrove (Conocarpus erecta) and aboundant cortadera (Cladium jamaicense); 3) Balneario Chichenkanaab, public park with low water level, dried shore vegetation; 4) Laguna de San Diego, water level very low, no water flow; 5) Villa Guadalupe cross road, the same situation, low water level, water not flowing; 6) Laguna La Esmeralda, same story, water not flowing, dried vegetation on former shore; 7) La Cenegosa was impossible to reach for lots of Cyperus grass invasion, the shores off limits, lots of deep mud; and 8) Santa Gertrudis Laggon, a former swamp now dried most of it, invaded by Cyperus grass locally called, la cortadora, at the end far away we could see an almost round bright green body of water surrounded completely by the same plant, local people called this area bad water and they assume it is a sinkhole or similar with underground water ways to the sea, for men and animals have been reported as lost and found away in the ocean. We found the location impacted by water loss even causing native mangrove vegetation to be dried, the shore bench one to two meters below the former zone, making water slow or not flowing, lots of biobild up material on the bottom (silt, mud, sludge, algae,) 30 to 70 cms deep, scum on top of the water, making it a very difficult for the fish to exist. The most common species found were Cyprindon verecundus, beltrany and labiosus at different locations, few C. maya at one location, few C. simus hybrids at the same spot, and C. suavum not found, perhaps completely lost for the type of feeding habits. We were able to collect a good number of fish, but many of them died very soon after collected, presenting diverse symptoms such as discoloration, bright color or red spots, belly swollen, popped eyes. The fish brought to the lab we made field imprint slides from the cloacal mucus, for further analysis on the lab. Two trios of C. labiosus, C. beltrani, and C. verecundus were carried to the lab, but were lost few days after arrival, not leaving any descendents. The imprints stained for Ziehl Neelsen gave positive results for Mycobacterium spp. , also some eggs, guts and excreta were used to do mycobacterial cultures with positive results, preliminary chemical tests points to Mycobacterium marinum, further work is on the go with PCR to corroborate these results. Apparently Mycobacterial infection is enzootic on the entire region in advanced state, making the fish sick and prone to die after being collected. We recommend not doing any further fish sampling until two or three years have passed to see if the species could recover once the habitat is cleaned by storms and heavy rains, and hope for habitat recover.