FIRST RECORDS OF MORPHOLOGICAL ABNORMALlTIES IN LEATHERJACK

Transcription

1 California Fish and Game 85(2): CALIFORNIA FISH ANO GAME FIRST RECORDS OF MORPHOLOGICAL ABNORMALlTIES IN LEATHERJACK ADRIAN F. GONZALEZ-ACOSTA, GUSTAVO DE LA CRUZ-AGÜERO, RUBEN RODRIGUEZ-SANCHEZ, JOSE DE LA CRUZ-AGÜERO, ANO JOSE LUIS CASTRO-AGUIRRE Coleccion Ictiologíca, Departamento de Pesquerias y Biologia Marina Centro Interdisciplinario de Ciencias Marinas I.P.N. AP. 592, Playa El Conchalito s/n La Paz, Baja California Sur, 23000, Mexico agacosta@hotmail.com In November 1997, 4 specimens of leatherjack, Oligoplites SGurUS, were caught using a modified stationary flume net (Melvor and Odum 1986, Gonzalez-Acosta ) deployed al the mouth of the tidal channel of El Conchalito mangrove swa01p, Laguna de La Paz, Baja California Sur, Mexico (24 08'17"N, '51 "W). Leatberjack were collected at temperatures ranging from 21.0 to 25.5 C, salinities from 37.1 to 41.5%0, and dissolved oxygen concentrations from 4.8 to 7.1 mg/1iter. Al! specimens were deposited and catalogued in the ichlbyological collection of Centro Interdisci p1inario de Ciencias Marinas (CICIMAR-IPN) (Series CI:4683). X-ray photographs revealed anomalies in 2 specimens: a curvature of the spinal column between the 1" and 11 th vertebrae (lordosis) in 1 fish (Fig. la), and a blunt and rounded apex of the upper jaw in the other fish (Fig. l c) that differs fro01 the normal mouth shape of leatherjack (Figs. 1 b and d). This malfonnation is perhaps due to the reduction of the frontal, nasal, or maxil!ary bones. (The x-ray was not clear enough to say which bones were affected). The number of spines and soft rays in dorsal and anal fins were the same as those published (Smith-Vaniz 1995), but gill rakers were fewer than previousjy reported (Table 1). Dawson (1964) and Dawson and Heal (1976) reviewed several cases of skeletal structural abnor01alities in fishes; however, this is the first record of defor01ities in leatherjack. Most teratologies probably occur during embryonic and larval development, which are usually associated with skeletal anomalies (Koumondourus et al. 1997). Lordosis may be caused by genetic factors, i.e., mutation, or the absence of a functional swim bladder (Chatain 1994), or induced by adverse environmental factors, such as temperature (Kocan et al. 1996), ascorbic acid (vitamin C) and mineral deficiencies (Wimberger 1993). Exposure to genotoxic substances, such as pesticides, oil, and heavy metals may cause hereditary deformations of the skeletal structure of fish (Lindesjoo and Thulin 1992) due to disorders in col!agen metabolism in bones (Chatain 1994). However, several abnormalities in fish have been caused t Gonzalez-Acosta, A.F Ecologia de la comunidad de peces asociada al manglar del estero El Conchalito, Ensenada de La Paz, Baja California Sur, Mexico. M.S. Thesis, Centro lnterdiciplinario de Ciencias Marinas-1PN, Mexico. 79

2 80 CALIFORNIA FISH ANO GAME Figure 1. X-ray photograph 01 leatherjack speeimens from El Conchalito mangrove swamp, Laguna de La Paz, Baja California Sur, Mexico. a) Specimen with lordosis, b) and d) normal fish and e) speeimen with abnormal upper jaw. by mechanical stress in aquacultural activities (Haaker 1977). The mandibular deformation observed here could be related to unfavorable environmental factors, as Carls and Rice (1990) consider extreme temperature as lhe main cause of deformed jaws. Although lordosis and other anomalies have a negative influence on morphology, growth, and survival oí' fi sh, sorne abnormal individuals can survive in natural populations for several years, as did specimens of northern anchovy, Engraulis mordax (Haaker 1977).

3 NOTES 81 Table 1. Measurements (mm) and eounts 01 leatherjaek speeimens in Fig. 1: a) Individual with lordosis, (e) speeimen with abnormal mouth, and normal fish (b and di. Characteristics Fish a Fish b Fish c Fish d Standard length L L08.3 Totallength Head length Lower jaw length Upper jaw length Ocular diameter Pectoral fin length Deep body Dorsa l fin V+I,20 V+I, 20 V+I,19 V+I,19 Anal fin II+I, l9 II+I,20 II+I, 19 II+I,l9 Gil! rakers (upper + lower) 6+14= = = =21 Number of venebrae ACKI\lOWLEDGMENTS We thank M. Torres Alfaro, Centro Interdisciplinario de Ciencias Marinas, Instituto Politecnico Nacional (CICIMAR-IPN), for help during sampling and P.L. Haaker and an anonymous reviewer for their useful comments. Consejo Nacional de Ciencia y Tecnolgia (CONACyT) and Direccion de Estudios de Posgrado e Investigacion del IPN (DEPI-IPN) supported this research. We also thank the Programa Institucional de Formacion de Investigadores del IPN (PIFI-IPN) and Comision de Fomento de las Actividades Academicas del IPN (COFAA). LlTERATURE GITED Carls, M. and S.D. Rice Abnormal development and growth reductions of pol!oek Theragra chalcogramma embryos exposed to waler-soluble fraetion of oi!. Fishery Bulletin 88: Chatain, B Abnormal swim bladder development and lordosi s in sea bass (Dicentrarchus labrax) and sea bream esparus aurarus). Aquaculture 119: Dawson, C.E A bibliography of anomalies of fish es. Gulf Re seareh Repon 1 : Dawson, C. E. and E. Hea! A bibliography of anomalies of fishes, Supplement 3. Gulf Research Report 5: Haaker, C.R Abnormal vertebral development in northern anchovy, Engrau/is mordax Girard. California Fish and Game 63: Kocan, R.M., J.E. Hose, E.D. Brown, anel T.T. Baker Pacifie herring (Clupea poi/osi) embryo sensivity to Prudhoe Bay petroleum hydrocarbons: Laboratory evaluation and in SilU exposure at oiled and unoiled siles in Prince William SOllnd. Canadian Journal of Fisheries and Aquatic Sciences 53: Koumoundourlls, G., F. Gagliarcli, P. Divanaeh, C. Bog.liOne, S. Catauclella, and M. Kentouri Normal and abnormal osleological clevelopment ol' caudal fin in Sparus al/rala L. fry. Aquaculture 92:

4 82 CALIFORNIA FISH ANO GAME Lindesjoo, E. and J. Thulin A skeletal eleformity of northern pike (Esox lucius) related to pulp mill efouents. Canaelian Journal of Fisheries and Aquatic Seienees 49: Mclvor, e.e. anel W.E. Oelum The Hume net: A qllantitative methoel for sampling fishes ancl macrocrustaceans on tidal marsh slirfaces. Estllaries 9: Smith- Vaniz, W.F Carangielae. Pages i/!: W. Fiseher, F. Krupp. W. Schneieler, e. Sommer, K.E. Carpenler, anel V.H. iem, eelilors. Guía FAO para la ielentific ac ión ele especies para los fines ele la pesca, Pacífico centro-oriental. Volume Ir, Food anel AgriclIlture Organizati on of tlle Uniteel Nations. Rome, Italy. Wimberger, P.H Effects of vitamin C deficiency on body shape and skull osteology in Geophagus brasiliensis: lmplicat ions for inlerprelations of morphological plasticity. Copeia 1993: Received: 16 Deeember 1998 Accepted: 30 April 1999

5 CALIFORNIA FISH and GAME "CONSERVATION THROUGH EDUCATION" VOLUME 85 SPRING 1999 NUMBER 2