Chaos of liquid surface waves in a vessel under vertical excitation with slowly modulated amplitude

Free surface waves in a cylinder of liquid under vertical excitation with slowly modulated amplitude are investigated in the current paper. It is shown by both theoretical analysis and numerical simulation that chaos may occur even for a single mode with modulation which can be used to explain Gollub and Meyer's experiment. The implied resonant mechanism accounting for this phenomenon is further elucidated.

Motor vessel "N. B. Scofield" cruise one of 1953. Cruise Report 53-S-1

(PDF contains 7 pages.)

A schematic analysis and discussion of species taken by otter trawl net by the research vessel Orion from July, 1965 to June 1966 in the Chesapeake Bay and major tributaries

From July 1965 to June 1964 the Natural Resources Institute's Research Vessel ORION took 16 minute tows with a forty (40) foot otter trawl net at 38 selected locations in Chesapeake Bay from the south of the Potomac River to Turkey Point at the head of the Bay and including some tributaries. Shallow and deep hauls were taken at most stations with depths ranging from 5 to 140 feet. A schematic summary of the 54 different species caught was compared with "Fishes of the Chesapeake Bay" by S. F. Hildebrand and W. C. Schroeder. Sixteen species including five not contained in the above references were selected for discussion. (PDF contains 21 pages)

Preliminary comparison of natural versus model-predicted recovery of vessel-generated seagrass injuries in Florida Keys National Marine Sanctuary

Each year, more than 500 motorized vessel groundings cause widespread damage to seagrasses in Florida Keys National Marine Sanctuary (FKNMS). Under Section 312 of the National Marine Sanctuaries Act (NMSA), any party responsible for the loss, injury, or destruction of any Sanctuary resource, including seagrass, is liable to the United States for response costs and resulting damages. As part of the damage assessment process, a cellular automata model is utilized to forecast seagrass recovery rates. Field validation of these forecasts was accomplished by comparing model-predicted percent recovery to that which was observed to be occurring naturally for 30 documented vessel grounding sites. Model recovery forecasts for both Thalassia testudinum and Syringodium filiforme exceeded natural recovery estimates for 93.1% and 89.5% of the sites, respectively. For Halodule wrightii, the number of over- and under-predictions by the model was similar. However, where under-estimation occurred, it was often severe, reflecting the well-known extraordinary growth potential of this opportunistic species. These preliminary findings indicate that the recovery model is consistently generous to Responsible Parties in that the model forecasts a much faster recovery than was observed to occur naturally, particularly for T. testudinum, the dominant seagrass species in the region and the species most often affected. Environmental setting (i.e., location, wave exposure) influences local seagrass landscape pattern and may also play a role in the recovery dynamics for a particular injury site. An examination of the relationship between selected environmental factors and injury recovery dynamics is currently underway. (PDF file contains 20 pages.)

Geographical distribution of the annual catches of yellowfin and skipjack tuna from the Eastern Tropical Pacific Ocean from vessel logbook records, 1952-1955

ENGLISH: The Inter-American Tropical Tuna Commission is engaged in scientific studies of the tuna resources of the Eastern Tropical Pacific Ocean. One of the most important aspects of these investigations is the evaluation of the effects of fishing upon the populations of yellowfin tuna (Neothunnus macropterus) and skipjack (Katsuwonus pelamis) of this region, based upon the analysis of quantitative records of fishing effort and catch. The systematic collection and compilation of statistical information on the operations and production of the tuna fishing Beet have, therefore, been essential parts of the research program since its inception in 1951. SPANISH: La Comisión Interamericana del Atún Tropical está dedicada al estudio cientifico de los recursos de atún del Océano Pacifico Oriental Tropical. Uno de los aspectos más importantes de las investigaciones es la evaluación de los efectos de la pesca sobre las poblaciones de atún aleta amarilla (Neothunnus macropterus) y barrilete (Katsuwonus pelamis) de esta región, sobre la base del análisis de los registros cuantitativos del esfuerzo de pesca y captura respectiva. La recolección sistemática y la compilación de informaciones estadisticas sobre las operaciones y producción de la flota pesquera de atún han sido, consecuentemente, de esencial importancia dentro de nuestro programa de trabajo desde su comienzo en 1951. (PDF contains 77 pages.)

Preliminary economic evaluation of 10 metre (LOA) shallow draft vessel in daily fishery, off Imo River, Cross River State

Scientists from the Institute with the collaboration of Food and Agricultural Organisation (FAO), Rome designed and built a 10-m (LOA) shallow draft vessel. The prototype vessel was tried at Uta-Ewa, Ikot Abasi, Cross River State. The paper deals with the preliminary economic analysis of the performance of prototype vessel. An analysis of the annual return has shown that 43.66% of the annual gross income was paid to labour; 15.91% was spent on repairs and replacements; 7.76% on fuel and lubricants; 24.38% on maintenance costs and the return of investment, 6.2%. This low return of investment is attributable to high percentage of labour costs as well as low fishing intensity

Australian Vessel Performance in the East Coast Tuna Longline Fishery

A sample of daily observations on the activities of Australian vessels longlining for yellowfin tuna, Thunnus albacares, during 1987-90 was analyzed, using a production junction approach, to determine the effects of vessel characteristics and operational practices and conditions. Significant differences were found between the tuna fisheries in the northern and southern regions of the inshore yellowfin tuna fishery in the east Australian Exclusive Economic Zone. The type of vessel used, and fishing practices such as soaktime, patrolling the longline, and choice of surface water temperature were found to have significant effects on yellowfin tuna catch rates.

Competing for the Recreational Dollar: An Analysis of the California Commercial Passenger-Carrying Fishing Vessel Industry

California has a large and diverse marine recreational fishery. Anglers on commercial passenger-carrying fishing vessels (CPFV's) harvest a substantial proportion of California's marine recreational fisheries landings, accounting for about 40 percent and 16 percent of the total 1986 marine recreational catch in southern and northern California, respectively (NMFS, 1987). In 1986, 459,369 CPFV anglers landed some 2,835,021 fish in southern California, while 200,925 CPFV anglers landed 1,240, 100 fish in central and northern California.