National Marine Fisheries Service

About: National Marine Fisheries Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Population & Fisheries management. The organization has 3949 authors who have published 7053 publications receiving 305073 citations. The organization is also known as: NOAA Fisheries & NOAA National Marine Fisheries Service.

Measuring Subjective and Objective Well-being: Analyses from Five Marine Commercial Fisheries

Abstract: Well-being is an important indicator of how participants in an industry are doing. Since the 1970s, anthropologists have been developing and utilizing "well-being" as an indicator, along with identifying the advantages and disadvantages of such a metric. Building on this experience, a "well-being" index is useful if it (1) is easily developed from available data; (2) enables temporal and spatial comparisons; (3) can be applied at multiple scales; and (4) possesses subjective and objective elements. The subjective element reflects how individuals and members of occupational communities perceive their situation. Using five case studies of North American marine commercial fisheries, an approach to representing subjective and objective measures of well-being is illustrated and evaluated. These studies show that commercial fishing has historically been a highly valued occupation from both subjective and objective perspectives. However, the status of commercial fishing has been in a state of decline over the pa...

Analysis of stomach contents of the porbeagle shark ( Lamna nasus Bonnaterre) in the northwest Atlantic

Abstract: Stomachs of 1022 porbeagle sharks (Lamna nasus) ranging in size from 85-264 cm were examined from the Canadian porbeagle shark fishery and a scientific cruise in the northwest Atlantic between February 1999 and January 2001. Teleosts occurred in the majority of stomachs and constituted 91% of the diet by weight. Cephalopods occurred in 12% and were the second most important food category consumed. Pelagic fish and cephalopods comprised the largest portion of the diet in the spring while groundfish dominated the diet in the fall. Diet did not differ significantly between the sexes. Stomach fullness differed slightly but significantly across months and declined slightly with fork length. The porbeagle is primarily an opportunistic piscivore with a diet characterized by a wide range of species. Diet composition changed seasonally following a migration from deep to shallow water.

Genetic architecture of growth and early life-history transitions in anadromous and derived freshwater populations of steelhead

Abstract: Heritabilities of growth, precocious maturation and smolting were measured in 75 families of juvenile steelhead or rainbow trout Oncorhynchus mykiss, progeny of within and between line matings (crosses) of wild, anadromous steelhead and wild, resident (lake) rainbow trout originally derived from the same anadromous stock 70 years earlier. The tagged yearling progeny were combined by line in common freshwater rearing containers and graded into three categories: mature, smolt or rearing (undifferentiated) at age 2 years. Heritabilities of precocious male maturity, smolting and growth were moderate to high, and the genetic correlation between growth and smolting was low. Smolting and precocious male maturity were highly variable among families within lines and significantly different between lines. Each of the four lines produced significant numbers of smolts at age two. Smolting and maturation were negatively genetically correlated, which may explain the persistence of smolting in the lake population despite strong selection against lake smolts; balancing selection on male maturation age may help to maintain variation for smolting. The high heritability of smolting, coupled with the inability of smolts that leave the lake to return to it indicates that the genetic potential for smolting can lie dormant or be maintained through a dynamic interaction between smolting and early maturation for decades despite complete selection against the phenotype. The results have significant implications for the preservation of threatened anadromous stocks in fresh water and the inclusion of resident fish of formerly anadromous populations, currently trapped behind long-standing barriers to migration, as one component of the same population.

Sexual Dimorphism in Wild Bottlenose Dolphins (Tursiops truncatus) from Sarasota, Florida

Abstract: We examined sexual dimorphism in external morphometric characters from 19 male and 32 female bottlenose dolphins ( Tursiops truncatus ) that were physically mature. These animals are long-term residents of the coastal waters near Sarasota, Florida, and were examined as part of an ongoing capture-release project. Males were significantly larger than females in 20 of 29 measurements; only one of eight measurements of the head showed significant absolute dimorphism. Proportional dimorphism (i.e., dimorphism corrected for body size) was less pronounced; only four linear measurements and three girth measurements exhibited significant differences between sexes. In addition, scarring of the dorsal fin occurred more frequently on males than on females. The occurrence of sexual dimorphism in this population of bottlenose dolphins is consistent with the model of a polygamous mating system.