Resumen.-El tiburón musola parda Mustelus henlei forma parte de una importante pesquería comercial en la costa occidental de Baja California Sur, México. Sin embargo, se han realizado muy pocos trabajos sobre biología, reproducción y alimentación de esta especie. Nuestro estudio, es el primer trabajo que se realiza en esta especie en la plataforma continental (14 m a 250 m de profundidad) de B.C.S. Mediante un análisis taxonómico, se identificaron un total de 24 tipos de presas, de los cuales 15 fueron crustáceos, 6 peces y 3 cefalópodos. De acuerdo al índice de importancia relativa (IIR) la presa principal fue la langostilla Pleuroncodes planipes (81,4%), seguida de la materia orgánica no identificada (MONI) (15,7%), la macarela Scomber japonicus (0,94%) y los restos de peces (0,84%). En el análisis de importancia de presas por sexos, se encontró que tanto en hembras como en machos, la langostilla P. planipens fue la presa más importante, después MONI y S. japonicus. Las especies importantes en la dieta del tiburón que se encontraron en zonas más profundas (120 a 150 m) a bordo del crucero BIP XII, fueron similares a las encontradas en la localidad más somera (14-40 m) de Punta Lobos, siendo la presa dominante la langostilla y también el MONI. De acuerdo al Índice de Levin M. henlei es considerado un tiburón especialista. Se observó una superposición de dieta por sexo, área y talla. Con el análisis SIMPER se muestró una baja similitud entre las dietas, con valor de significancia reducida entre sexos, tallas y áreas. De acuerdo a la prueba ANOSIM no se encontraron diferencias significativas. El conocer que M. henlei presenta un comportamiento especialista puede ayudar no sólo a la conservación de la especie, sino de su hábitat y de los organismos que se encuentran en él y que son de vital importancia para el tiburón.Palabras clave: Contenido estomacal, superposición de dieta, especialista, Punta Lobos, Baja California Sur, MéxicoAbstract.-The Brown smooth-hound Mustelus henlei is part of an important commercial fishery on the western coast of Baja California Sur (BCS), Mexico. However, very few studies have been performed on the feeding and reproduction biology of these sharks in Mexico. Our study is the first work focusing on this species on the western shelf (14 m to 250 m in depth) of B.C.S. We identified a total of 24 types of prey contents in the stomachs of M. henlei: 15 crustaceans, 6 fish, and 3 cephalopods. According to the index of relative importance (IRI) the main prey items for M. henlei was the pelagic red crab Pleuroncodes planipes (81.4%), followed by unidentified organic material (UOM) (15.7%), the mackerel Scomber japonicus (0.94%), and fish remains (0.84%). Conducting a prey analysis considering sex of M. henlei, P. planipes was the most important prey in both females and males, followed by UOM, and S. japonicus. Sharks found in deeper areas (120-150 m) and those caught on board the exploration ship BIP XII had a similar dietary composition to those found in the shallow waters of Punta Lobos (...
Four new malformations observed in blue shark embryos in the western coast of Baja California Sur, Mexico are reported in this study. The embryos of blue shark samples were obtained on board the industrial fishing boat ‘Damasta’; the organisms were frozen and transferred to CIBNOR Fish Ecology Laboratory where the corresponding measurements were taken and malformations observed. The first malformation was the presence of one nostril in two female embryos that showed short and crushed snouts. The second one was observed in a female with two jaws and the middle portion of the column trunk in screw-shape. The third one was an embryo with dicephaly, two separate vertebral columns, two first dorsal fin pairs, absence of the second dorsal fin, five pelvic fins and two joint caudal fins. The fourth malformation observed was an embryo with incomplete development and undifferentiated sex. Malformations are still a mystery and also an object of study because they affect different organisms, not only sharks but also fish. It is highly relevant to know the causes and perform further studies to understand if the origin is either genetic or anthropogenic.
Background: Malformations of the Round stingray Urobatis hallerii, Cooper 1863 captured off the southwestern coast of Baja California Sur, México are reported in this study. Methods: The ray was an adult male captured by artisanal fishery in the area of Estero Banderitas. Size measurements of total length and disk width were taken; the organism could be photographed when captured. Results: Malformations of U. hallerii were found in the posterior part of the spine, a distortion in the upper part of the tail and in the left fin close to the tail. The specimen was considered able to reach the adult size usually reported in other specimens of this species despite the spine malformations because of its benthic habits and not losing its mobility completely. Conclusions: The observed malformations were likely due to genetic alterations although other studies are needed to see if other environmental factors could cause malformations in marine organisms mainly in fish and elasmobranchs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.