The study evaluates the hybridizations between two African catfish, C. gariepinus and macromystax, using artificial reproduction. Fecundity gonadosomatic index were assessed, growth performance at different developmental stages was evaluated. results indicated that both species possess a similar index. parent possesses significantly (p < 0.05) higher male reproductive quality than macromysta...

  Reproduction and spawning patterns of the king fish (Scomberomorus commerson) were studied in the Persian Gulf (Hormozgan Province) and Oman Sea from Oct 2006 to Sep 2007. A total of 1120 fish was collected from different landing sites along the Iranian waters. Yearly analysis of the reproductive stages and gonadosomatic index showed a single reproductive cycle beginning in March and continue...

The freshwater crab Aegla platensis was used as a model to induce ovarian growth by adding different neuroregulators to a pellet food formulation. Added compounds were the dopaminergic inhibitor spiperone or the enkephalinergic inhibitor naloxone, both of them at a dose of 10(-8) mol/animal. Animals were fed on the enriched pellets twice a week. After 7 wk, the gonadosomatic index (GI) was calc...

Munida subrugosawas sampled monthly from November 1997 to November 1999 in the Beagle Channel by means of an epibenthic trawl. The reproductive cycle started in May, re£ected by the occurrence of ovigerous females. Maximum size of oocytes, maximum value of gonadosomatic index in females (16.8 gmmcarapace length [CL]71) and males (1.6 gmmCL71), and the proportion ( 70%) of ovigerous females with...

Adult Channa punctatus murrels of both sexes (60-80 g) were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month) throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960) and Fiske and Subbarow (1925), respectively. Gonads were fixed to judge the state of maturati...

The Las Vegas Wash (LW) delivers tertiary-treated municipal wastewater effluent, nonpotable shallow groundwater seepage, and runoff from the urbanized Las Vegas Valley to Las Vegas Bay (LX) of Lake Mead. To investigate the potential for contaminants in LW influent to produce effects indicative of endocrine disruption in vivo, adult male and female common carp (Cyprinus carpio) were exposed in c...

Chronic environmental stress is known to induce evolutionary change. Here, we assessed male life-history trait divergence in the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but reproductively isolated toxic/nontoxic and surface/cave habitats. Examining both field-caught and common garden-reared specimens, we in...

This study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analy...