Growth profiles of male Cyprinus carpio, 12 uninfected (healthy) and 12 infected with the crustacean Argulus indicus and associated fungus Saprolegnia sp. are presented. The fish were maintained under controlled conditions and provided with ad libitum food for 8 weeks. The instantaneous (G) and relative (h) rates of growth, and production (P) in uninfected carp (0.003 to 0.036 g.d-', 0.29 to 3.68%, 0.25 to 3.23 grespectively)weremuchhigherthan thoseofinfectedcarp( -0.007 too.021 g.d-',0.71 to 2.17x, 0.59 to 1.76 g). The condition factor (K) for uninfected carp was 4.5 to 4.8 compared to 2.6 to 3.0 for infected carp. During each of the 8 wk the weekly change in weight of infected carp was about 4% less than that of uninfected carp. These data show that Argulus-Saprolegnia infections significantly suppress carp growth and indicate that comparative growth rates can be used as indicators of parasite stress.
An investigation was made of the physical, chemical conditions of the water and substrate of nursery-cum-research-cum-rearing-cum-stocking ponds at Central Inland Fisheries Research Institute, Kamal. Temperature, pH, CO 2 , dissolved oxygen, chloride, phosphate, alkalinity, nitrates, organic matter, total solids, turbidity, electric conductivity, nitrogen, P 20 S , sand, silt, clay, Caco l , etc. were measured monthly. Statistical analysis of these factors showed some significant correlations. The phyto-and zooplankton were also sampled and the seasonal changes in abundance recorded.
Morphological and taxonomic descriptions are given of an erpobdellid found to be a new species of Erpobdella Blainville, 1818 collected from Montezuma Well, Arizona, U.S.A. Mature individuals of Erpobdella montezuma sp. nov. do not exceed 71 mm total length, have three pairs of eyes with the second and third pairs smaller, and have dorsal paramedial stripes that are densely pigmented. On the dorsum and venter of each annulus lie 14–18 small white-tipped papillae containing the sensory organs. Six pairs of bunches of large testicular follicles (three to five in a bunch) are present. The morphological and anatomical variations between E. punctata and E. montezuma are described.
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