Studies of the effects of industrial pollution in the lower Patapsco river area: 1. Curtis Bay Region 1941

Industrial effluents in the lower Patapsco area, which constitutes the navigable portion of the river and includes Baltimore Harbor, are many and include waste acid, distillery waters, tannery wastes and copper as (ferrous sulphate) from pigment and steel industries. (PDF contains 22 pages (2 on 1)

Problems of industrial fisheries development in the Cross River State

The industrial fisheries as opposed to artisanal fisheries in Cross River State, Nigeria, is discussed, considering the prospect of industrial fisheries in the State and identifying the major fish and shrimp resources within the coastal waters. Industrial fishing was introduced in 1973 when the state government invited a Japaneese company to carry out a joint exploratory shrimp fishing venture. The contributions made by the Seastate Seafoods Company, the Eyib's Nutritional Food and the Arawak Fishing Companies towards the increase in the number of fishing fleet in the state are noted.

Design of a Recreational Fishing Survey and Mark-Recapture Study for the Blue Crab, Callinectes sapidus, in Chesapeake Bay

The development of bay wide estimates of recreational harvest has been identified as a high priority by the Chesapeake Bay Scientific Advisory Committee (CBSAC) and by the Chesapeake Bay Program as reflected in the Chesapeake Bay Blue Crab Fishery Management Plan (Chesapeake Bay Program 1996). In addition, the BiState Blue Crab Commission (BBCAC), formed in 1996 by mandate from the legislatures of Maryland and Virginia to advise on crab management, has also recognized the importance of estimating the levels and trends in catches in the recreational fishery. Recently, the BBCAC has adopted limit and target biological reference points. These analyses have been predicated on assumptions regarding the relative magnitude of the recreational and commercial catch. The reference points depend on determination of the total number of crabs removed from the population. In essence, the number removed by the various fishery sectors, represents a minimum estimate of the population size. If a major fishery sector is not represented, the total population will be accordingly underestimated. If the relative contribution of the unrepresented sector is constant over time and harvests the same components of the population as the other sectors, it may be argued that the population estimate derived from the other sectors is biased but still adequately represents trends in population size over time. If either of the two constraints mentioned above is not met, the validity of relative trends over time is suspect. With the recent increases in the human population in the Chesapeake Bay watershed, there is reason to be concerned that the recreational catch may not have been a constant proportion of the total harvest over time. It is important to assess the catch characteristics and the magnitude of the recreational fishery to evaluate this potential bias. (PDF contains 70 pages)

The design of multimesh, multidepth gillnet fleets for use in the Lake Victoria Fisheries Research Project

Multimesh, multidepth gillnet fleets are useful in assessing fish stock abundance, size distribution and depth distribution. Using data collected on net mesh selectivity for Nile perch, Lates niloticus (L.), in the Kenyan waters of Lake Victoria, suitable mesh sizes for gillnet fleets for use in the Lake Victoria Fisheries Research Project were determined. The modal selection length for Nile perch in the mesh sized used in the earlier experiment were determined, as was the size range vulnerable to capture. Initial trials suggest 60% of the Nile perch swim within 5 m of the bottom. Setting and hauling of the nets is simple and quick, allowing the nets to be used at the same time as other sampling programmes.

Movements of bocaccio (Sebastes paucispinis) and greenspotted (S. chlorostictus) rockfishes in a Monterey submarine canyon: implications for the design of marine reserves

In August and September of 1997 and 1998, we used SCUBA techniques to surgically implant Vemco V16 series acoustic transmitters in 6 greenspotted rockfish (Sebastes chlorostictus) and 16 bocaccio (S. paucispinis) on the flank of Soquel Canyon in Monterey Bay, California. Fish were captured at depths of 100–200 m and reeled up to a depth of approximately 20 m, where a team of SCUBA divers anesthetized and surgically implanted acoustic transmitters in them. Tagged fish were released on the seafloor at the location of catch. An array of recording receivers on the seafloor enabled the tracking of horizontal and vertical fish movements for a three-month period. Greenspotted rockfish tagged in 1997 exhibited almost no vertical movement and showed limited horizontal movement. Two of these tagged fish spent more than 90% of the time in a 0.58-km2 area. Three other tagged greenspotted rockfish spent more than 60% of the time in a 1.6-km2 area but displayed frequent horizontal movements of at least 3 km. Bocaccio exhibited somewhat greater movements. Of the 16 bocaccio tagged in 1998, 10 spent less than 10% of the time in the approximately 12-km2 study area. One fish stayed in the study area for about 50% of the study time. Signals from the remaining 5 fish were recorded in the study area the entire time. Bocaccio frequently moved vertically 10–20 m and occasionally displayed vertical movements of 100 m or greater.

Design of a half ton dehydrator for fish

A half-ton capacity artificial dryer has been designed at the Central Institute of Fisheries Technology for drying fish like Mackerel, Sardine, White bait etc. The dryer is a hot air recirculation type. 80 KW thermostatically controlled heating coils are made use of for heating the air. The air is circulated by means of an axial flow pattern fan. Drying takes place at a temperature of 115 degrees F. The structure of the dryer comes to about Rs. 20,000.

General principles of the design of trawl net

The classification and the principles of design and construction of trawls in general are described. The method of calculating the length of rope required at each part for mounting the net and the requirements of floats and sinkers are given. The cutting rates to tailor machine made webbing are also indicated.

A case study on the impact of industrial effluent disposal on the fishery of Amba River estuary, Maharashtra

The impact of waste discharge on fishery resources is a matter of great concern. The accepted norm in all environmental impact assessment studies is to avoid areas of high fishery potential while locating a marine outfall. Contemplating on this aspect a case study was conducted in the Amba River estuary before and after the establishment of a petrochemical complex at Nagothane. The treated wastewater from this complex is released through a subsurface outfall after adopting effective control measures for marine disposal of waste. Experimental trawling was done at five locations covering a distance of 30 km during 1990 to 1991. The catch rate within the estuary varied from 0.6 to 255 kg/h (av 24 kg/h). The trend indicated considerable decrease in fishery potential from the mouth of the estuary (av 64 kg/h) to the upstream location (av 11 kg/h). A total of 49 species of fishes, 16 species of prawns, 7 species of crabs and 1 species of lobster were identified from the collections. Number of species gradually increased from the interior segment at Dharamtar (8) to the outer area near Revas (18). A comparison of the quantitative and qualitative nature of the post outfall and pre outfall data revealed only marginal difference. The study indicates that if necessary precautions are taken to render the waste harmless the marine ecology will hardly be affected.

Design of refrigerated sea water plant for preservation of fish

To study the feasibility of employing refrigerated sea water on board fishing vessels for the preservation of fish, a pilot model has been designed, the details of which are presented in this paper.

Design of a detachable type fish drier

The paper describes the design of a detachable type fish drier which has been designed to operate on commercial scale. The drier with a raw material capacity of one tons has been designed after effecting all improvements on the design of the existing tunnel driers available in India. The cost of one drier works out to Rs. 2,16,700/- approximately.