Photo thermal induced effects on testes and pituitary gonadotropic cells during resting phase of reproductive cycle in a murrel, Channa punctatus (Bloch)

Effects of various combinations of photoperiod and temperature (NL-NT, LD 15:9-28°C, NL-28°C and LD 15:9 NT) were studied on testicular activity and pituitary gonadotropic cells in Channa punctatus during resting phase of reproductive cycle. Long photoperiod (LD 15:9-28°C) and warm temperature (NL-28°C) regimes were found to be more effective for testicular maturation and secretory activity of gonadotropic cells suggesting testicular maturation via brain-pituitary-testicular axis.

A description of certain indigenous fishing methods from Southern Dahomey

A survey of certain Dahomean fishing methods showed them to be specifically adapted to the exploitation of floodplains and shallow water lagoons. Several types of fish-parks are described, ranging from small installations thaI funclion as refuge traps, to larger constructions that act as a form of fish culture. Ponds are also dug in the floodplains in order to conserve fish isolated during the dry season. These methods all give high yields and are worthy of consideration for use elsewhere on the African continent.

La reproducción de la merluza en el Mar Argentino (Merlucciidae, Meluccius merluccius hubbsi) : 1. Descripción histológica del ciclo del ovario de merluza

The present paper deals on the histological description of the hake ovary made on the basis of gonad observations of 394 females during the period April 1966 March 1967. The material was obtained from weekly sampling of commercial catches carried out at the Institute of Marine Biology (Prov. Buenos Aires, Argentina). The anatomical and histological description of the standard ovary and the adopted terminology are given. The maturation process is divided into five periods, from ovocyte formation to yolked ovocyte formation, with its histological description. Ovary changes are analyzed on detail. The following conclusions were outlined: 1. Analysis demonstrated that although some specimens were totally spawned others, at the end of the spawning period, retaining a great number of ovocytes in different maturity stages. Therefore, postspawners have been classified as follows: Postspawned II : This stages is characterized by the empty ovarian structure, with ovocytes in stage II, which will remain in the resting phase untill next spawning season. Postspawned III and IV: Their main characteristics are: tissue destruction, bloody residuals and remaining ovocytes in stage III and IV, respectively. 2. Some transformations were found in ovaries of postspawned III and IV. They are classified as follows, according to its origin and structure: Developed from follicular cell membrane – a) Glandular formations, b) Epiteloid formations - Originated from remaining ovocytes, c) Ovocyte disintegration, d) Ovocyte with follicular cell infiltration. 3. All those structures derived from postpawners III and IV have a temporary character and will be reabsorbed. Their presence delay the recuperation of the organ and its reproductive functions. Consequently, the possibility of those structures acting as control mechanisms is suggested. 4. Transformations pointed out in paragraph Nº 2 prevent the possibility of consecutive spawning originated from the remaining ovocytes (II and IV). 5. No structures originated from postspawners III and IV were found during summer season. 6. Reproductive cycle of hake has been described monthly. It was observed that maturing ovaries predominate in summer (November-December).