Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 30 for “"commercial fishery"”.
-
The commercial fishery for sharks in the South-Western Cape, with an analysis of the biology of the two principal target species, Callorhinchus Capensis Dumeril and Galeorhinus Galeus Linn
The South African shark fishery began in World War 2, based on a demand for shark liver oil. The initial landings are estimated at 3750 tons per annum, but have since declined to approximately 820 tons of shark, principally Galeorhinus galeus, with an additional 800 tons of Callorhjncbus capensis. …
-
Summer Movements of Bigmouth Buffalo in Lake Poinsett, South Dakota
… An evaluation of large mesh gill nets as a commercial fishery tool indicated that 10.0 cm bar measure gill nets were most effective for harvesting bigmouth buffalo in Lake Poinsett.
-
Relationships between climate, growth and fisheries production in a commercially exploited marine fish
… relationships of fish captured by the commercial fishery to each climate and environmental variable using an exponential model. Fish growth rate was measured using otolith chronologies for juveniles (years 0-2) and adult (years 3-10). Lastly, annual catch data from the commercial …
-
Livelihoods of small-scale fishers of Struisbaai : implications for Marine Protected Area planning.
… coast of Struisbaai. The others are: a migratory commercial line fishery, boat and shore-based recreational fishery, chokka squid commercial fishery, and commercial trawlers. The overall aim of this study is to understand the human (social, economic, cultural and institutional) dimensions of the …
-
Ecology of the migration and distribution of the anchovy Engraulis capensis off Namibia
… and age composition were also obtained from the commercial fishery statistics. Stomach contents extracted from samples of anchovy shoals were compared to water samples from their environment. Data on diet obtained from the fishery catch statistics are analysed to indicate feeding trends.
-
Understanding links between flow regime and fish populations in the Saskatchewan River Delta
… were removed from fish sampled from the commercial fishery at Cumberland Lake, Saskatchewan. Cohort strength was then estimated by assigning the year of hatch to individual fish. The cohort strength was compared against discharge from a gauge below the E.B. Campbell hydroelectric …
-
Growth and Yield-Per-Recruit Modeling of Spot (<i>Leiostomus xanthurus</i>) in the Chesapeake Bay, and a Comparison of Biological Reference Points
<p>Spot were sampled from the Chesapeake Bay commercial fishery from 1993–1995 to determine if spot are overfished. Transversely sectioned otoliths were determined to be the most appropriate structure for ageing spot. It was determined that spot have a high natural mortality rate (M = 0.9) and fast …
-
An investigation of diet management strategies for the culture of the South African abalone, Haliotis midae
… many of the I 00 or so species of abalone are commercially and recreationally exploited. The continuing demand for abalone has resulted in the overexploitation of wild stocks throughout the world. ·Most commercial abalone fisheries are characterised by high yields at the beginning of the …
-
Use Of Multi-Gear Sampling To Improve Abundance Estimates Of Demersal Coregonids In The Laurentian Great Lakes
… the Laurentian Great Lakes food webs and the commercial fishing industry. Hydroacoustic sampling has proven useful when performing stock assessments because hydroacoustics provide rapid spatial coverage as well as lower size and species selectivity compared to other assessment methods. The …
-
Biophysical interactions in the Iceland Basin
… link between primary producers and the important commercial fishery for Atlantic Cod. However, one result of ocean warming is that the distribution of the cold water loving Calanus finmarchicus is being pushed northwards which adversely affects the food supply to juvenile Cod. Perhaps of more …
-
Quantifying Discard Mortality of Undersized and Ovigerous Crabs in the Gulf of Mexico Blue Crab Fishery
<p>Blue crabs support a valuable commercial fishery in the Gulf of Mexico. Most states require the release of undersized and ovigerous blue crabs, yet mortality of these discarded crabs is an understudied component of total mortality. The first objective of this project was to quantify discard …
-
ESTIMATION OF MORTALITY RATES FOR THE GULF MENHADEN STOCK AND REFERENCE POINT IMPLEMENTATION FOR THE FISHERY
… Gulf menhaden stock is the target of a large commercial fishery in the Gulf of Mexico. To address the needs of both the stock and fishery, I performed two studies. I first addressed the natural mortality rates currently used in the Gulf menhaden stock assessment. To update these rates, I used …
-
Determining the Trophic Role of Gulf Menhaden (<i>Brevoortia patronus</i>) Using Carbon and Nitrogen Stable Isotopes
… finfish. Gulf menhaden also support a large commercial fishery, and little is known about the impact of fishing on the role of this species as a filter feeder in the food web. This study examines the spatial, temporal and ontogenetic dynamics of food selectivity and trophic role observed in …
-
Spatial Distribution and Stock-Recruitment Analysis of the Atlantic Surfclam, <i>Spisula solidissima</i>, in the Mid-Atlantic Bight and on Georges Bank
… <p>Atlantic surfclams support a major commercial fishery in the western North Atlantic Ocean. The stock is not and historically has not been overfished nor has overfishing occurred; however, in recent years landings per unit effort have declined. A species distribution function model …
-
Life-History Characteristics and Fishery Dynamics of Red Drum (<i>Sciaenops ocellatus</i>), in the North-Central Gulf of Mexico
… in the Gulf of Mexico, and support a small commercial fishery in Mississippi. Despite their popularity, the stock is assessed using data limited approaches that necessitate accurate life history information. I estimated the year-specific and year-aggregated escapement rates for the …
-
Management Strategy Evaluation for the Atlantic Surfclam, <i>Spisula solidissima</i>, Using a Fisheries Economics Model
… surfclam productivity in the MAB and increased fishery viability as indicated by improvement in performance metrics. The active agents of the MSE model are individual fishing boats with economic and quota constraints influenced by captain’s behaviors over a spatially varying population. …
-
Entangled Eden: ecological change and the Lake Huron Commercial Fisheries, 1835-1978
… and investigates the causative role of the commercial fisheries in that change. The repeated failures of various regional and international efforts designed to improve management of the lake’s fisheries are also examined. The fundamental argument is that economic considerations were the …
-
Climate impacts and adaptation in the Dungeness crab fishery: a social-ecological systems perspective
… it supports one of the largest and most valuable commercial fisheries, as well as culturally important recreational and subsistence harvests. Yet over the past decade, Dungeness crab fisheries have faced numerous closures from the effects of long-term ocean change and associated extreme events. My …
-
Population structure of lake trout (Salvelinus namaycush) In Atlin Lake, British Columbia and contributions to local fisheries: a microsatellite DNA-based assessment
… stock analysis of samples collected from the commercial fishery and recreational anglers indicated that all of the genetic subpopulations contribute to the fishery along with lake trout subpopulations in the interconnecting Tagish Lake; suggesting that no one subpopulation is being depleted by …
-
In-Stream Reactivity of Dissolved Organic Matter and Nutrients in Proglacial Watersheds
… ecologically productive marine zone and valuable commercial fishery. Furthermore, this study provides information about watersheds undergoing glacial recession to GOA basin-wide estimates of DOM export and future research initiatives focusing on in-stream DOM processing.
Page 1 of 2