First record of partial albinism in two catfish species of Genidens (Siluriformes: Ariidae) in an estuary of Southern Brazil

Abstract

ABSTRACT

First Report of Albinism in the Threatened Gillbacker Sea Catfish Sciades parkeri (Siluriformes, Ariidae)

“…Belly pale. This study presents the first record of albinism in Sciades parkeri, a threatened species [ 4 ], increasing albinism in Ariidae family [ 8,9 ] and expands records for Amazon estuary. Albinism is an inherited condition genetically determined or environmentally induced, that results in little or total absence of pigment in the skin and eyes [ 10,11 ].…”

“…Although considered rare in vertebrate groups [ 12 ], the albinism in fish is most common, as it is, in Elasmobranchii fishes such as sharks and stingrays (e.g. [ [13][14][15][16] ]) and also Catfishes, as well as representatives of the families Ariidae, Ictaluridae, Loriicaridae, Pimelodidae and Siluridae [ 8,9 ]. It is worth mentioning that it seems more common in Ariidae species that, likewise most sharks and stingrays, inhabit brackish and marine waters, whereas the other aforementioned families inhabit freshwater strictly.…”

“…cave species), however, this phenomenon is still poorly understood in cave biology [ 12 ]. Taking into account that albino specimens are more susceptible to predation than non-abnormal colored specimens [ 8 ], it is very interesting that the S. parkeri albino reported here has achieved sexual maturity, which is calculated to individuals around 50 to 70 cm SL [ 5,7 ]. In addition, it is known that albinos have pathological deficiencies, such as weak vision [ 8,16 ], for this reason it is most common in nocturnal fish (i.e.cryptobiotic) such as the Batrachoididae pacuma toadfish [ 17 ] and Anguillidae eels [ 18 ].…”

“…Taking into account that albino specimens are more susceptible to predation than non-abnormal colored specimens [ 8 ], it is very interesting that the S. parkeri albino reported here has achieved sexual maturity, which is calculated to individuals around 50 to 70 cm SL [ 5,7 ]. In addition, it is known that albinos have pathological deficiencies, such as weak vision [ 8,16 ], for this reason it is most common in nocturnal fish (i.e.cryptobiotic) such as the Batrachoididae pacuma toadfish [ 17 ] and Anguillidae eels [ 18 ]. However, we can expect that the latter is not a major disadvantage for S. parkeri in the Amazon estuary due to the high concentration of suspended sediments thus, nearly zero visibility conditions, obligating fish and other aquatic fauna to depend on other sensory organs.…”

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“…Albinism and leucism have been observed in different varieties of animals including fishes and they are not exclusive to any ecological or taxonomical group. It has been reported in more than 20 species of teleost and 36 species of cartilaginous fishes from freshwater and marine environment www.trjfas.org ISSN 1303-2712DOI: 10.4194/1303-2712 worldwide (Veena, Thomas, Raje, & Durgekar, 2011;Leal, Horst-Schulz, Lehmann-Albornoz, Machado, & Ott, 2013;Wakida-Kusunoki & Amador-del-Ángel, 2013). …”