This study estimated age and growth of the largest extant fish, the whale shark (Rhincodon typus) by counting vertebral band pairs from 92 specimens comprising 43 males (2.68–9.88 m total length [TL]), 30 females (1.60–7.02 m TL), and 19 unsexed individuals (2.83–6.67 m TL) taken by Taiwanese commercial fisheries during 2001–06. Growth band pairs up to 25 and 42 were counted for a 6.38-m TL female and a 9.88-m TL male, respectively. Using marginal increment ratio and centrum edge analysis, band pairs were postulated to be formed twice a year. The two-parameter von Bertalanffy growth function provided the best fit without significant differences between sexes. Growth parameters were calculated for both sexes as L∞ = 16.80 m TL, k = 0.037 year–1; annual band pair formation would modify these parameters to L∞ = 15.34 m TL, k = 0.021 year–1. Using data reported in another study for 50% size at maturity for males (8.1 m TL), and the largest immature and smallest mature females (8.7 and 9.6 m TL, respectively) in the Indo-Pacific, these TLs converted to ages at maturity of 17 years for males and 19–22 years for females. The longevity was calculated to be 80.4 years.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Animal Ecology. Summary 1. This paper examines the population biology of two related species of bothriocephalid cestodes, parasites of teleostean fish, which live in sympatry. One species, Bothriocephalus barbatus, needs in its life cycle only one obligatory intermediate host, a copepod. The second species, B. gregarius, needs the same intermediate host first, but also utilizes a non-obligatory paratenic host, which is a gobiid fish. In the case of B. gregarius, definitive hosts can be infested via the intermediate host or the paratenic host. A simple mathematical model was built to investigate the effect of the addition of a paratenic host into the life cycle of a parasite. Results of the simulation clearly demonstrated that the maintenance or absence of infectivity of cestode larvae in the paratenic host could explain the observed levels of infection in both definitive hosts. 3. Acquisition of paratenic hosts has two advantages: the recovery of lost infective stages in a previously non-suitable intermediate host, and an increase in the time of infection during which the definitive host could be infected as the result of eatingcopepods in its planctonophagous juvenile existence and by eating gobies in its predaceous older stages. 4. Using the basic transmission rate as a measure of fitness, we also investigated the possibility of maturation of B. gregarius in the paratenic host, e.g. the acquisition of a new definitive host by the parasite. Basic transmission rates and numerical simulations suggest that there is no benefit for the parasite in evolving towards this strategy.

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Age and growth ofthe turbot (P. maxima L., 1758) and the brill (S. rhombus L., 1758) in the Gulf of Lion.The a e and rowth of the turbot and the brill have been determined with otoliths (sagitta). On these otolit~s, the krmation of the hyaline zone can be seen in the summer and an opaque zone in the winter. In both species, the two sexes have identical length/weight relationships. By contrast, the are wide divergences in the age/length and age/weight relationships. At the same age in both species, Kmales are always longer and heavier than males. Zusammenfassung Alter und Wachstum von Psetta maxima&INN& 1758) und Scophthalmus rhombus (LINN~, 1758) im Golfvon Lion Das Alter und das Wachstum des Steinbutts (P. maxima L., 1758) und des Butts (S. rhombus L., 1758) wurden auf Grund der Morphologie und der Grof3e der Sagitta ermittelt. Der Otolith wies im Friihjahr eine durchsichtige und im Winter eine undurchsichtige Zone auf. Unabhkgig vom Geschlecht war die Beziehung Lan e Gewicht bei beiden Gattungen gleich. Dagegen wurden gerin e Unterschiede in den Beziehungen Afte-r-Grofle und Alter-Gewicht festgestellt. Bei Tieren gleichen Afters beider Gattungen sind die Weibchen groider und schwerer als die Mknchen. R h m 6 Age et croissance de Psetta maxima (LINN~?, 1758) et Scophthalmus rhombus INN^, 1758) duns le Golfe du Lion L'ige et la croissance du turbot (P. maxima L., 1758) et de la barbue (S. hornb bus L., 1758) sont analyses h pa& d'une etude morphologique et dimensionnelle de la sagitta. Sur cet otolithe, une zone hyaline s'observe au printemps et une zone opaque en hiver. Quel que soit le sexe, nous observons la mGme relations taille-masse chez les deux esplrces. I1 existe par contre de Ikgkres divergences pour les relations i e-taille et ige-oids. Dans les deux esplrces, au meme ige, les femelles sont toujours plus grandes et p k s lourdes que i s miles.

The occurrence of the cysticercoïd stage of the bird tapeworm Flamingolepis liguloïdes (Cestoda, Cyclophyllidea) was studied across the salt marshes of the French Mediterranean coast. It was observed in 11 populations of the intermediate host Artemia (Crustacea, Anostraca) and investigated. A relationship between the prevalence of the parasite in Artemia and the population density of flamingoes on the sites studied is shown by the results. Parasitism in the infected host populations increases with the size of Artemia. Cysticercoïds are found in the thorax of juvenile Artemia, whereas they are packed in the abdomen in the adults. During growth of Artemia, the localisation of parasites is related to allometric changes in the thorax/abdomen proportion. In infected populations, up to 22.8% of Artemia are red coloured and present an altered behaviour. These physiological and ethological changes are discussed in terms of adaptive strategy by the parasite.