ÍNDICES PARASITOLÓGICOS DE LA MERLUZA PERUANA MERLUCCIUS GAYI PERUANUS (GINSBURG, 1954) (PERCIFORMES: MERLUCCIIDAE) ADQUIRIDOS DEL TERMINAL PESQUERO DE VENTANILLA, CALLAO, PERÚ

La “Merluza peruana” Merluccius gayi peruanus (Ginsburg, 1954), es la especie más abundante y económicamente importante en la pesquería de arrastre de fondo en el Perú. El objetivo del presente trabajo fue evaluar los índices parasitológicos de la merluza peruana M. gayi peruanus procedentes del Terminal Pesquero de Ventanilla durante los meses de enero a febrero del 2014. Se recogieron los parásitos, se fijaron, preservaron y se cuantificaron mediante procedimientos estandarizados. Se colectó un total de quince especies parásitas, con una abundancia media total y de riqueza de especies de 1,55 y 0,90. Los ectoparásitos estuvieron representados por el monogeneo Anthocotyle americana y los copépodos Caligus debueni, y Neobrachiella insidiosa pacifica. Los endoparásitos por los digeneos Aporocotyle wilhelmi, Derogenes varicus y Lecithochirium genypteri. Los cestodos fueron Diphyllobothrium pacificum, Diphyllobothrium arctocephalinum, Callitetrarhynchus gracilis, Grillotia dollfusi y Clestobothrium crassiceps. Los nematodos se identificaron como Anisakis simplex y Contracaecum sp. Los acantocefalos corresponden a Corynosoma obtuscens y Bolbosoma sp. Clestobothrium crassiceps, A. wilhelmi, A. americana y A. simplex presentaron la mayor frecuencia de dominancia. La prevalencia y abundancia media de C. crassiceps estuvo asociada con la longitud total del hospedero. Solo A. wilhelmi, presentó valores de factor de condición de la merluza peruana más altos en los peces no parasitados. Los índices de interactividad (CC ) de ectoparásitos y endoparásitos mostraron que 50 las comunidades parasitarias fueron mayormente no interactivas o aisladas. Los cuatro estimadores no paramétricos Chao-2, Jacknife-1, Jacknife-2 y Bootstrap para determinar la riqueza de especies parasitas indicaron que se requiere aumentar el esfuerzo de muestreo en la merluza peruana.

SEM evidence for existence of an apical disc on the scolex of Clestobothrium crassiceps (Rudolphi, 1819): comparative results of various fixation techniques

The scolex of the bothriocephalidean cestode Clestobothrium crassiceps was studied by means of scanning electron microscopy (SEM). The comparative results of various fixation procedures and techniques are presented. The scolex of C. crassiceps is oval to globular and exhibits two deep bothria which appear in the form of two lobes separated by a longitudinal groove. At the apex of the scolex, resembling a beret, an apical disc is present (oval, flattened and with a sinuous edge). Our results are compared with those previously reported in other species of Clestobothrium. This study represents the first report which highlights the presence of an apical disc in the scolex of C. crassiceps. It describes the effects of different procedures applied to our material during preparation and a comparative analysis results obtained using these various methods.

Ultrastructure and cytochemistry of vitellogenesis and the vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758) (Gadiformes, Merlucciidae)

Vitellogenesis and vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758), were studied by means of transmission electron microscopy (TEM) and cytochemistry. During vitellogenesis, four developmental stages were distinguished at the TEM level: (I) a stem cell stage of the gonial type; (II) an early differentiation stage, predominantly exhibiting lipid and protein synthetic activity; (III) an advanced differentiation or vitellocyte maturation stage, primarily exhibiting active glycogenesis still accompanied by an increase in lipid accumulation; and (IV) a mature vitellocyte stage. Vitellogenesis involves: (1) an increase in cell volume; (2) an extensive development of parallel, frequently concentrically arranged, cisternae of granular endoplasmic reticulum (GER) that produce dense, proteinaceous shell-gobules; (3) the development of Golgi complexes engaged in the packaging of this material; (4) an accelerated accumulation of unsaturated and saturated lipid droplets, along with their continuous enlargement and fusion; (5) the formation of individual β-glycogen particles and α-glycogen rosettes and their accumulation in the form of glycogen islands scattered among lipid droplets in the cytoplasm of maturing and mature vitellocytes; and (6) the rapid accumulation of large, saturated lipid droplets accompanied by dense accumulations of α- and β-glycogen along with proteinaceous shell-globules or shell-globule clusters in the peripheral layer during the advanced stage of vitellocyte maturation. Vitellogenesis in C. crassiceps generally resembles that previously described for three other bothriocephalideans, but differs from that of other cestode orders. Cytochemical staining with periodic acid-thiocarbazide-silver proteinate for glycogen indicates a strongly positive reaction for β-glycogen particles and α-glycogen rosettes, which form several large glycogen accumulations around the large, saturated lipid droplets of maturing and mature vitellocytes. Some hypotheses concerning the interrelationships between patterns of vitellogenesis, the possible modes of egg formation, embryonic development and life cycles in cestodes, and their phylogenetic implications are commented upon.

Cestoda and monogenea of some teleost fishes off the Mudanya Coast (Sea of Marmara, Turkey)

The following helminths are reported from the Sea of Marmara off the Mudanya coast. Cestoda: Didymobothrium rudolphii in Solea solea, Clestobothrium crassiceps in Merluccius merluccius, tetraphyllidean larvae in Gobius niger, G. cobitis, M. merluccius, Eutrigla gurnardus, S. solea, Scorpaena scrofa and Progrillotia dasyatidis in G. niger. Monogenea: Trochopus pini in E. gurnardus, Ligophorus confusus in Liza ramada, Tetraonchoides paradoxus in Uranoscopus scaber, Microcotyle mugilis in L. ramada and Anthocotyle merluccii in M. merluccius.

A comparison of the structure of the scolex of Bothriocephalus scorpii (Müller 1776) and Clestobothrium crassiceps (Rud. 1819) and the mode of attachment of the scolex to the intestine of the host

1. Two Pseudophyllidea, Bothriocephalus scorpii (Müller) and Clestobothrium crassiceps (Rud.), have been obtained from Scophthalmus maximus (L.) and Merluccius merluccius (L.) respectively, from fishing grounds to the west of the British Isles.2. The musculature of the scolex in both has been compared relative to the form and mode of function of that organ. All the major groups of muscles are present in both, but their arrangement is modified in C. crassiceps, due to the presence of hemispherical bothria, instead of open grooves, and a sphincter muscle around the bothrial opening.3. The mode of attachment is discussed briefly in C. crassiceps, and in more detail in B. scorpii, where the structure of the scolex was found to be admirably suited to the form of the host's mucosa. The effect on the mucosa is slight, due to the absence of very powerful muscles and of other specialized adhesive structures.4. The nervous system of the scolex in both species has been compared, and a fundamental similarity has been found. Modifications in C. crassiceps are associated with shortening of the scolex and the difference in form of the bothria.5. The excretory system shows the same correlation with the form of the scolex.

THE METAZOAN PARASITES OF THE HETEROSOMATA OF THE GULF OF ST. LAWRENCE: IV. CESTODA

Diplocotyle olrikii, Clestobothrium crassiceps, Bothriocephalus scorpii, and B. claviceps; Scolex pleuronectis, Phyllobothrium sp. (larva), and a tetraphillidean plerocercoid (Cestoda) were identified in a study of 560 specimens of Heterosomata (Hippoglossoides platessoides, Hippoglossus hippoglossus, Limanda ferruginea, Liopsetta putnami, Pseudopleuronectes americanus, and Scophthalmus aquosus) from the Gulf of St. Lawrence area. The distribution of the hosts is indicated.

THE CESTODA OF CANADIAN FISHES III. ADDITIONS TO THE PACIFIC COASTAL FAUNA

An additional collection of cestode material from the Canadian Pacific coastal region comprised Ligula intestinalis, Schistocephalus solidus, Clestobothrium crassiceps, Grillotia erinacea and Proteocephalus arcticus. The common tetrarhynchoid larva of Ophiodon elongatus is identified with Nybelinia surmenicola Okada and some notes upon its biology are given.