Norman Mercado-Silva

Helminth Parasites of Freshwater Fishes of the Pánuco River Basin, East Central Mexico

Abstract This study presents results from a survey of helminth parasites of fishes in the Pánuco River basin, in the states of San Luis Potosí, Hidalgo, Querétaro and Guanajuato, all in east central Mexico. Seventeen freshwater fish species (n = 1,019) were examined for helminths between May 1997 and September 1998. Thirty-one helminth species were collected: 11 allogenic species, mostly Nearctic in origin, and 20 autogenic species. Two anthropogenically introduced species were recorded. The most prevalent and widespread helminth taxon was Posthodiplostomum minimum (metacercariae). The helminth fauna of fishes of the Pánuco River is dominated by trematodes (12 species) and nematodes (11 species) accompanied by a few monogenean (4 species), cestode (3 species), and acanthocephalan (1 species) taxa. Most of the helminth taxa reported have been reported from other regions of Mexico. Thus, the helminth parasite fauna of fishes of the Pánuco River basin are not exclusive, including a primordially autogenic Neotropical species component mixed with a mainly allogenic, globally distributed Nearctic species component. The regional freshwater fish helminth fauna is associated with the ichthyofaunanal composition of the basin. The nematode family Rhabdochonidae displays high species richness in this hydrological basin of Mexico.

Validation of a fish-based index of biotic integrity for streams and rivers of central Mexico

An existing version of a fish assemblage-basedindex of biotic integrity (IBI) for the streamsand rivers of west central Mexico was testedwith independent data to validate itsusefulness as a measure of ecosystem qualityand to determine the geographic area where itis effective. Fish assemblages from 63 uplandsites in 10 basins in central Mexico(Armería, Ameca, Coahuayana, Marabasco,Purificación, Grande de Morelia, Grande deSantiago, Lerma, Balsas and Pánuco) wereassessed using the metrics and scoring criteriafrom the existing IBI and then compared withindependent evaluations of habitat and waterquality. IBI scores were congruent withhabitat and water quality values in theArmería, Purificación and Marabascobasins, where the IBI was first developed, aswell as in the adjacent Ameca and Coahuayanabasins. We conclude that the IBI can be usedwithout modification to assess environmentalquality in non-coastal streams and riverswithin these five basins. Further data areneeded from the Grande de Morelia, Grande deSantiago and middle Lerma basins, but ourresults suggest that the existing IBI may alsobe effective here. However, the existing IBIdoes not consistently reflect habitat and waterquality conditions in the Balsas and Pánucobasins and must be modified before it can beapplied there. Necessary modifications in theBalsas basin appear to be small and relatedprimarily to changes in the scoring criteriafor metrics. However, in the Pánuco basinmore substantive changes in the nature of themetrics are required. Changes in the IBI forthese basins are proposed. The IBI is nowvalidated for use in river monitoring,conservation and restoration efforts in 5basins in west central Mexico and suggestionsfor its application in other basins areavailable here.

Helminth Parasites of Freshwater Fishes of the Ayuquila River, Sierra de Manantlán Biosphere Reserve, West Central Mexico

Abstract This study presents results from the first survey of the helminth parasites of fishes in the Ayuquila River, Sierra de Manantlán Biosphere Reserve, in the states of Jalisco and Colima, west central Mexico. Twenty-eight helminth species were collected from 14 freshwater fish species in July 2000 and February 2001. No helminth species collected is exclusive to the Ayuquila River: 11 are allogenic species, mostly Nearctic in origin, and 17 are autogenics. Three introduced species were recovered. Saccocoelioides sogandaresi (Trematoda) was the most prevalent and widespread helminth recovered. The fish helminth fauna of the Ayuquila River is dominated by trematode and nematode species with only a few monogenean and acanthocephalan species. The fauna exhibits considerable overlap with that reported for other freshwater basins in Mexico, and all helminths recovered have been reported previously from Mexico.

Systematics and Biogeography of the Silverside Tribe Menidiini (Teleostomi: Atherinopsidae) Based on the Mitochondrial ND2 Gene

Abstract The silverside fish tribe Menidiini (Teleostei: Atherinopsidae) consists of four genera, Menidia, Labidesthes, Poblana, and Chirostoma, that are distributed along the Atlantic coast of North America, throughout the Gulf of México, insular United States, and the Mesa Central of México. It has been suggested that Chirostoma, Poblana, and Menidia should be recognized as a single genus under the nominal Menidia. To test this hypothesis, phylogenetic relationships within the tribe Menidiini were assessed using the mitochondrially encoded ND2 gene. Monophyly of the Menidiini tribe was supported. Results also failed to support monophyly for the genera Menidia and Chirostoma as currently recognized. A central Mexican clade, inclusive of Chirostoma and Poblana, was recovered as monophyletic and strongly supported. Relationships within the Mesa Central clade support a previously recognized “humboldtianum” clade and the paraphyly of Chirostoma with respect to Poblana.

Impact of rainbow smelt (Osmerus mordax) invasion on walleye (Sander vitreus) recruitment in Wisconsin lakes

Rainbow smelt (Osmerus mordax) are invaders of inland lakes in the Laurentian Great Lakes region of North America and have negatively affected native fish populations. Walleye (Sander vitreus) comprise an important fishery throughout the Great Lakes region and could be affected by rainbow smelt invasions. We test for declines of young-of-the-year walleye (YOY-W) density in 12 of the 26 known rainbow smelt invaded lakes in Wisconsin. Invaded lakes showed significantly lower YOY-W densities than uninvaded lakes during the period 1985–2004. In 94% (17/18) of years, YOY-W densities from invaded lakes were lower than those from uninvaded lakes. Declines (~70%) in YOY-W densities were observed in three lakes with data from before and after rainbow smelt invasion. For 10 invaded lakes with more than two YOY-W density estimates between 1985 and 2004, YOY-W densities averaged 13% below expected densities. Our results demonstrate the potential impacts of rainbow smelt invasion on walleye tribal, commercial, and rec...

Notropis calabazas (Teleostei; Cyprinidae): New Species from the Rio Panuco Basin of Central Mexico

Abstract A new species of cyprinid, Notropis calabazas, is described from the Río Calabazas, a small tributary of the Río Verde in the Río Pánuco basin in San Luis Potosí state, central México. It belongs to the Notropis calientis complex, which is defined primarily on the occurrence of reduced and interrupted cephalic and lateralis sensory canals. Notropis calabazas is unique in having 17 or more gill rakers on the second gill arch versus 16 or fewer. Notropis calabazas can also be distinguished from the other three members of the complex by its relatively high numbers of gill rakers on the first arch, total lateral line scales, pored lateral line scales, body circumferential scale rows and caudal peduncle circumferential scale rows, and its relatively low numbers of supraorbital and infraorbital cephalic sensory pores. Notropis calabazas is uncommon within its limited range and warrants official designation as a protected species.

Threatened fishes of the world: Chirostoma aculeatum Barbour, 1973 (Atherinopsidae)

Chirostoma aculeatum is a rare silverside found only in central Mexico. Its conservation status is considered in addition to providing information regarding its ecology, life history, and distribution.

Edmundo Díaz Pardo (1945–2013)

E MINENT Mexican ichthyologist EDMUNDO DÍAZPARDO passed away 6 November 2013 in the City of La Piedad, State of Michoacán, Mexico, at the age of 68. ‘‘Mundo,’’ as he was known to his students, friends, and colleagues, was a dedicated educator, academic, and mentor who enthusiastically shared his experience and knowledge of Mexican ichthyology with numerous generations of students at various institutions in Mexico, Europe, and North and Central America. Edmundo was born in Mexico City on 20 November 1945 to Gregorio Dı́az Palacios and Clemencia Pardo Alegre. He majored inBiology in 1969at theEscuela NacionaldeCienciasBiológicas of the Instituto Politécnico Nacional (ENCB-IPN) in Mexico City. His undergraduate thesis ‘‘Anatomı́a del tubo digestivo de Lepisosteus tropicus Gill, 1863’’ (Anatomy of the digestive tract of Lepisosteus tropicus Gill, 1863) was one of the first of his many contributions to ichthyology and natural resources conservation in Mexico. After graduation, he continued his education at ENCB-IPN, where he completed M.S. and Ph.D. degrees in 1980 and 1992, respectively. While completing his graduate degrees, he also served several roles at ENCB-IPN. He was Chief and Curator of the Laboratory of Chordates between 1975–1991, and later Chief and Curator of the Ichthyology and Limnology Laboratorybetween1991–2001.After retiring from the Instituto Politécnico Nacional in 2002, he went on to become a professor at the Facultad de Ciencias Naturales (Biology) of the Universidad Autónoma de Querétaro (UAQ), where he founded and served as Curator of the Central Mexico Fish Collection. Edmundo’s academic activity transcended education and research institutions. He co-founded the Mexican Ichthyological Society (SIMAC), which he later led as President between 1998 and 2000. In recognition of his work in the society and as an academic, SIMAC appointed him in 2006 as an Honorary Member. He also co-founded the Mexican Association of Limnology and the Mesoamerican Network of Biotic Resources, a group dedicated to conservation and biological research throughout Mesoamerica. Sharing his knowledge about natural resources and ichthyology was important to Edmundo; throughout his career he gave more than 100 conference presentations and invited talks at diverse venues, both in Mexico and abroad. In addition to his work with scientific societies, Edmundo was a soughtafter authority who participated in the design of several regulations and codes for the legal protection of natural resources in Mexico. He participated as a member of the commissions responsible for designing the official Mexican 1994, 2001, and 2010 ‘‘red lists’’ (generally identified as NOM-ECOL-059) identifying species at risk or under a special conservation status. Despite being a recognized academic and having served many important administrative roles at research institutions, Edmundo was adamantly against elitism in the academic realm; it was easy to get him going against superiority in academia. Edmundo understood the value of zoological collections and fomented their formation and use. Following the steps of his mentor, Dr. José Álvarez del Villar, he expanded and established several fish collections at numerous academic institutions in Mexico. In addition to the expansion of the Ichthyological Collection at ENCB (with acronym COPEMEX, ENCB-IPN-P), he also worked on establishing the fish collections at the Universidad Autónoma de Querétaro (UAQ–PCM) and the Universidad Autónoma de Morelos (CP-UAEM); these two collections today bear his name. He, along with other important already departed ichthyologists including J. Álvarez del Villar, Salvador Contreras Balderas, and Andrés Reséndez Medina, can be considered among the pillars of ichthyology in Mexico. Edmundo’s international academic activity included work as a visiting researcher with Dr. C. L. Hubbs (Scripps Institution of Oceanography, University of California–San Diego) in 1973. In 2000 he participated as a visiting researcher at the Museo Nacional de Ciencias Naturales de Madrid, Spain, where he actively collaborated with Dr. I. Doadrio Villarejo. In 2008 he was a guest academic at Auburn University (Alabama, USA). In the late 2000s he also interacted with numerous collaborators in Nicaragua, Guatemala, and Costa Rica via the Mesoamerican Network of Biotic Resources. Throughout his career he worked in close collaboration with several U.S.-based scientists with interests in Mexican fishes (e.g., Henry L. Bart–Tulane University; John Lyons–University of Wisconsin; Barry Chernoff–Wesleyan University, among many others), which often resulted in new discoveries and advances in our knowledge of freshwater fishes. Edmundo was a teacher for numerous generations of biologists at the Instituto Politécnico Nacional, the Universidad Autónoma del Estado de Morelos, the Universidad Autónoma de Querétaro, and the Universidad Michoacana