Etnografía y alimentación entre los Toba-Nachilamole#ek y wichí-Lhuku’tas del Chaco Central (Argentina), Cap. 1, 2 y 3.

Se reproducen tres capítulos relacionados con la ictiología del libro de Pastor Arenas, gracias a su gentileza.

The relationship between otolith increments and time for yellowfin and skipjack tuna marked with tetracycline

ENGLISH: The rate at which increments are deposited on the sagittal otoliths of yellowfin (Thunnus albacares) and skipjack (Katsuwonus p elamis) tunas is determined by a markrecapture experiment using tetracycline. During growth in fork length from 40 to 110 em, and for a period of up to 389 days, yellowfin of the Revillagigedo Islands- Baja California region deposit one increment per day in either the postrostrum or rostrum position of the otolith. For skipjack of the same region, rostrum increments underestimate time by approximately 24 percent during growth from 42 to 64 cm and over the maximum interval of 249 days. The growth rate of each species is estimated from the recapture fork length and the linear change in an otolith dimension following tetracycline injection. Over specific ranges in fork length the rates are 3.06 and 1.15 em per month for yellowfin and skipjack, respectively. SPANISH: La rapidez (tasa) en la que se depositan los incrementos en los otolitos sagitales del aleta amarilla (Thunnus albacares) y el barrilete (Katsuwonus pelamis) se determina mediante un experimento al recapturar los peces que han sido marcados con tetraciclina. Durante el crecimiento de la longitud de horquilla de 40 a 110 cm y por un período hasta de 389 días, se forma en el aleta amarilla de la región de las Islas Revillagigedo-Baja California, un incremento diario ya sea en el parte del postrostrum o rostrum de los otolitos. Con respecto al barrilete de la misma region los incrementos en el rostrum subestiman aproximadamente el tiempo en un 24 por ciento durante el crecimiento de 42 a 64 cm y sobre un intervalo máximo de 249 días. El índice de crecimiento de cada especie se estima en la recaptura según la longitud de horquilla y el cambio lineal en la dimensión de un otolito después de la inyección de tetraciclina. La variación específica sobre la longitud de horquilla de los índices son 3.06 y 1.15 cm por mes para el aleta amarilla y el barrilete, respectivamente. (PDF contains 54 pages.)

The integrated approach of water hyacinth control on Lake Kainji: with special regard to the design, construction and installation of a water hyacinth barrier across the River Niger

This document lists the undesirable effects of water hyacinth (Eichhornia crassipes) on fisheries in Lake Kainji (Nigeria) and the integrated Water Hyacinth Control Programme in its ongoing fisheries management and development activities on the lake. Special regard is given to the design, construction and installation of a water hyacinth barrier across the River Niger. (PDF contains 44 pages)

Studies of the effects from extracts from two local plants (Tephrosia vogelii and Parkia clappertoniana) on Clarias gariepinus (Tengels)

Studies were carried out using 96hr static toxicity bioassay to determine the effect of lethal concentrations of extracts from two local plants Tephrosia vogelii and Parkia clappertoniana which are known fish poison, on a species of mud fish. Clarias gariepinus Phytochemical analysis of the plant extracts was done and the extract from T. vogelii was found to contain alkaloids, tannins and flavonoids, while the extract from P. clappertoniana was formed to contain alkaloids tannins and saponins. Experimental fish were exposed to test water separately polluted by varying concentrations of extraction of both plant species ranging from 0.50mgl super(-1), 1.50mgl super(-1), 2.50mgl super(-1), 3.0mgl super(-1), 5.00mgl super(-1), 10.00mgl super(-1) in the case of T. vogelii and 5.00mgl super(-1), 7.50mgl super(-1), 10.00mgl super(-1), 15.00mgl super(-1), 20.00mgl super(-1) and 30.00mgl super(-1) in the case of P. clappertaniana. Behavioural hispathological and heamatological examinations were made. Both plant extracts were found to have lethal effects at the higher concentrations, affecting the gills and the central nervous system as well as having a depressive effect on the total count and increasing platelet and white blood cell count. Symptoms of toxicosis observed include, initial inactivation agitated swimming, tumbling movement air gulping, increased opercular beat and period of quiescence/knockdown before death. Marked differences were also observed in the hematological and histopathological analysis of poisoned fish. Lower concentrations of the extracts had sub lethal effects on the fish, which manifested as zigzag movement air gulping increased opercular movement etc. None of these effects were observed in the control experiment

Food and feeding habits of Heterotis niloticus from River Kaduna floodplain

A total of 61 Heterotis niloticus specimen were examined and evaluated to determine the food and feeding habits using the frequency of occurrence, point and dominance methods. The specimens had mean standard length of 27.09 plus or minus 4.73cm, total length of 33.40cm body weight of 90-900g. The gut length ranges from 34-104cm while the gut weight range from 2.79-130g. It was observed that the fish fed mostly on plankton with rotifers and polyscysits having the highest number of frequency and dominant value with mean value of 43.03 plus or minus 4.12 and 11.73 plus or minus 1.15, 37.45 plus or minus 3.27 and 8.32 plus or minus 0.38 respectively. Arcella had the least mean frequency of occurrence of 3.27 plus or minus 17. Amoeba sp had the least mean dominance value of 7.06 plus or minus 50 and Aphnocapsa sp had the least mean frequency of occurrence of 1.10 plus or minus 0.29 and Navicula sp had the least mean dominance value of 4.31 plus or minus 1.11. Heterotis niloticus of River Kaduna flood plain is therefore considered to be predominantly planktivorous

Variations temporelles de Vibrio cholerae Non 01 et conditions environnementales dans un site aquacole (Lagune Ebrié, Côte d'Ivoire)

The annual cycle of Vibrio cholerae in the environment surrounding the Layo aquaculture facility (Ebrié lagoon) was studied from March 1991 to April 1992. Vibrio cholerae counts were coupled with the determination of physical and chemical characteristics of water and the estimation of biological richness of this environment.

Les saisons marines devant Abidjan

From March 1966 to March 1970 some hydrographic observations were collected twice a week at a coastal station, off Abidjan. These data show the alternation of well defined water masses over the Ivorian Continental shelf. Grouping all observations on a T-S diagram, it is possible to differentiate four marine seasons, which are typical of an austral type of climate such as is observed off Pointe Noire.

Forensic Fisheries Science: Literature Review and Research Suggestions

Recent years have seen a dramatic increase in litigation against the National Marine Fisheries Service, NOAA. Litigation may affect personnel throughout the agency, including scientists, whose work is often directly or indirectly influenced by complex legal requirements, but who may not be in a position to comment or engage in public dialogue. It may be helpful for scientists and other agency personnel to join the ongoing discussion in the legal community regarding the interface of science and law. This paper provides a starting point with a selected introduction to relevant legal literature in this area. It uses the phrase “forensic fisheries science” to describe the application of science to legal requirements in the fishery management context. It concludes with suggestions for future research that could assist NMFS scientists as they grapple with the challenge of using science to help the agency meet its complex legal requirements. Forensic: belonging to, used in, or suitable to courts of judicature or to public discussion and debate; argumentative, rhetorical; relating to or dealing with the application of scientific knowledge to legal problems (Merriam-Webster Online Dictionary )

A Review of Stock Identification of Haddock, Melanogrammus aeglefinus, in the Northwest Atlantic Ocean

Haddock, Melanogrammus aeglefinus, is a principal commercial species distributed throughout the northwest Atlantic Ocean, with major aggregations occurring on Georges Bank and on the Scotian Shelf. This review examines all available information on stock structure of haddock to evaluate the suitability of current stock units and to investigate areas that require further research. Combined information from tag-recapture, demographic, recruitment, meristic, parasitic, and genetic studies provide evidence for the identification of haddock stocks, with major population divisions occurring between New England, Nova Scotia, and Newfoundland waters. Within each of these major divisions a number of discrete stocks appear to exist, although uncertainty remains in the amount of separation found within each region. Research utilizing more recent stock identification techniques should refine and improve our understanding of haddock stock structure in the northwest Atlantic.

Regional Fisheries Advisory Committee 4th March, 1985

This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 4th March, 1985. The report contains sections on Public Water Supplies in West Cumbria, proposals for water supply for British Nuclear Fuels Limited (BNFL), and the proposals for a fish pass at Ennerdale Weir. The section on BNFL looks at the proposal of British Nuclear Fuels Limited to take more water from Wastwater. This section includes information about Wastwater, Calder Valley Boreholes, Mine Water and the River Ehen, and other groundwater investigations. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Climatological data in Mexico [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): This is a previous presentation of what has been observed in points spread in Mexico. The existing data amount is large enough that an atlas was given out in 1977. This atlas has information which goes back to the beginning of the country. The original data sets from which this atlas was issued exist in a variety of storage forms ranging from simple paper blocks up to books and magnetic tapes.

Tag-reporting levels for red drum (Sciaenops ocellatus) caught by anglers in South Carolina and Georgia estuaries

A total of 1784 legal-size (≥356 mm TL) hatchery-produced red drum (Sciaenops ocellatus) were tagged and released to estimate tag-reporting levels of recreational anglers in South Carolina (SC) and Georgia (GA). Twelve groups of legal-size fish (~150 fish/group) were released. Half of the fish of each group were tagged with an external tag with the message “reward” and the other half of the fish were implanted with tags with the message “$100 reward.” These fish were released into two estuaries in each state (n=4); three replicate groups were released at different sites within each estuary (n=12). From results obtained in previous tag return experiments conducted by wildlife and fisheries biologists, it was hypothesized that reporting would be maximized at a reward level of $100/tag. Reporting level for the “reward” tags was estimated by dividing the number of “reward” tags returned by the number of “$100 reward” tags returned. The cumulative return level for both tag messages was 22.7 (±1.9)% in SC and 25.8 (±4.1)% in GA. These return levels were typical of those recorded by other red drum tagging programs in the region. Return data were partitioned according to verbal survey information obtained from anglers who reported tagged fish. Based on this partitioned data set, 14.3 (±2.1)% of “reward” tags were returned in SC, and 25.5 (±2.3)% of “$100 reward” tags were returned. This finding indicates that only 56.7% of the fish captured with “reward” tags were reported in SC. The pattern was similar for GA where 19.1 (±10.6)% of “reward” message tags were returned as compared with 30.1 (±15.6)% for “$100 reward” message tags. This difference yielded a reporting level of 63% for “reward” tags in GA. Currently, 50% is used as the estimate for the angler reporting level in population models for red drum and a number of other coastal finfish species in the South Atlantic region of the United States. Based on results of our study, the commonly used reporting estimate may result in an overestimate of angler exploitation for red drum.