794 resultados para Northeastern Technical College
Resumo:
This study, part of a broader investigation of the history of exploitation of right whales, Balaena glacialis, in the western North Atlantic, emphasizes U.S. shore whaling from Maine to Delaware (from lat. 45°N to 38°30'N) in the period 1620–1924. Our broader study of the entire catch history is intended to provide an empirical basis for assessing past distribution and abundance of this whale population. Shore whaling may have begun at Cape Cod, Mass., in the 1620’s or 1630’s; it was certainly underway there by 1668. Right whale catches in New England waters peaked before 1725, and shore whaling at Cape Cod, Martha’s Vineyard, and Nantucket continued to decline through the rest of the 18th century. Right whales continued to be taken opportunistically in Massachusetts, however, until the early 20th century. They were hunted in Narragansett Bay, R.I., as early as 1662, and desultory whaling continued in Rhode Island until at least 1828. Shore whaling in Connecticut may have begun in the middle 1600’s, continuing there until at least 1718. Long Island shore whaling spanned the period 1650–1924. From its Dutch origins in the 1630’s, a persistent shore whaling enterprise developed in Delaware Bay and along the New Jersey shore. Although this activity was most profi table in New Jersey in the early 1700’s, it continued there until at least the 1820’s. Whaling in all areas of the northeastern United States was seasonal, with most catches in the winter and spring. Historically, right whales appear to have been essentially absent from coastal waters south of Maine during the summer and autumn. Based on documented references to specific whale kills, about 750–950 right whales were taken between Maine and Delaware, from 1620 to 1924. Using production statistics in British customs records, the estimated total secured catch of right whales in New England, New York, and Pennsylvania between 1696 and 1734 was 3,839 whales based on oil and 2,049 based on baleen. After adjusting these totals for hunting loss (loss-rate correction factor = 1.2), we estimate that 4,607 (oil) or 2,459 (baleen) right whales were removed from the stock in this region during the 38-year period 1696–1734. A cumulative catch estimate of the stock’s size in 1724 is 1,100–1,200. Although recent evidence of occurrence and movements suggests that right whales continue to use their traditional migratory corridor along the U.S. east coast, the catch history indicates that this stock was much larger in the 1600’s and early 1700’s than it is today. Right whale hunting in the eastern United States ended by the early 1900’s, and the species has been protected throughout the North Atlantic since the mid 1930’s. Among the possible reasons for the relatively slow stock recovery are: the very small number of whales that survived the whaling era to become founders, a decline in environmental carrying capacity, and, especially in recent decades, mortality from ship strikes and entanglement in fishing gear.
Resumo:
The abundance of the common starfish, Asterias forbesi, fluctuates widely over time. The starfish is a predator of pre-recruit northern quahogs, Mercenaria mercenaria. During the 1990’s, starfish became scarce in Raritan Bay and Long Island Sound. Quahog populations concurrently erupted in abundance and quahog landings have risen sharply in both locations. The extensive scale of this observation would seem to imply a cause and effect; at the least, both populations may be responding differently to a large scale exogenous factor.
Resumo:
The annual catches of four small longliners operating off northeast Brazil from 1983 to 1997 were examined across different areas and locations. The total catch comprised tunas (30%), sharks (54%), billfishes (12%), and other fish species (4%). Fishing strategy and annual composition of catches showed large spatial and temporal variabilities with the dominant catches alternating among yellowfin tuna, Thunnus albacares; gray sharks, Carcharhinus spp.; and blue shark, Prionace glauca. Catches of blue and gray sharks showed a significant interaction among seamounts, with gray sharks occurring in maximum abundance around those seamounts that had relatively deep summits and low-sloping depth profiles. Results are discussed in terms of the various factors that may have influenced distribution of effort.
Resumo:
Red snapper, Lutjanus campechanus, is subject to significant overfishing in U.S. Gulf of Mexico waters, and regulations are being implemented to reduce fishing mortality and restore them to a 20% spawning potential ratio by the year 2009. One source of mortality that must be reduced to achieve this goal is the incidental capture ofjuvenile red snappers in shrimp, Penaeus spp., trawls. NOAA's National Marine Fisheries Service is conducting research to develop shrimp trawl modifications to reduce the snapper bycatch. An important part of this research is the study of juvenile red snapper behavior on commercial shrimp grounds and in relation to trawling gear. An area of high juvenile red snapper abundance was identified off the coast of Mississippi. Most snappers were observed around structures or objects on the bottom which they appeared to use for refuge or orientation. Those ranging over barren bottom had no apparent point of orientation. When encountered by shrimp trawls, most juvenile snappers rose above the trawl footrope and fell back into the trawl. These observations have directed research toward modifying shrimp trawls to release juvenile red snappers after entry, rather than preventing them from entering a shrimp trawl.
Resumo:
This study examined the technical efficiency in artisanal fisheries in Lagos State of Nigeria. The study employed a two stage random sampling procedure for the selection of 120 respondents. The analytical techniques involved descriptive statistics and estimation of technical efficiency following maximum likelihood estimation (MLE) procedure available in FRONTIER 4.1. The MLE result of the stochastic frontier production function showed that hired labour, cost of repair and capital items are critical factors that influences productivity of artisanal fishermen with the coefficient of hired labour being highly elastic. This implies that employing more labour will significantly increase the catch in the study area. The predicted farm efficiency with an average value of 0.92 showed that there is a marginal potential of about 8 percent to increase the catch, hence the income of the fishermen. The study further examined the factors that influence productivity of fishermen in the study area. Year of education, mode of operation and frequency of fishing have important implication on the technical efficiency of fishermen in the study area.