Maturity, ovarian cycle, fecundity, and age-specific parturition of black rockfish (Sebastes melanops)

From 1995 to 1998, we collected female black rockfish (Sebastes melanops) off Oregon in order to describe their basic reproductive life history and determine age-specific fecundity and temporal patterns in parturition. Female black rockfish had a 50% probability of being mature at 394 mm fork length and 7.5 years-of-age. The proportion of mature fish age 10 or older significantly decreased each year of this study, from 0.511 in 1996 to 0.145 in 1998. Parturition occurred between mid-January and mid-March, and peaked in February. We observed a trend of older females extruding larvae earlier in the spawning season and of younger fish primarily responsible for larval production during the later part of the season. There were differences in absolute fecundity at age between female black rockfish with prefertilization oocytes and female black rockfish with fertilized eggs; fertilized-egg fecundity estimates were considered superior. The likelihood of yolked oocytes reaching the developing embryo stage increased with maternal age. Absolute fecundity estimates (based on fertilized eggs) ranged from 299,302 embryos for a 6-year-old female to 948,152 embryos for a 16-year-old female. Relative fecundity (based on fertilized eggs) increased with age from 374 eggs/g for fish age 6 to 549 eggs/g for fish age 16.

Solar-cycle modulations of ENSO: a possible source of climatic change

An association between long-term changes in the solar cycle and the frequency of El Niño events has been identified in historical records of El Niño and sunspot number. Although no known mechanism can explain the apparent relationship, the association is strong. A possible coupling between the sun and the ocean's mixed layer, involving ENSO, is worthy of further study.

Exploratory analysis of resource demand and the environmental footprint of future aquaculture development using Life Cycle Assessment

Increases in fish demand in the coming decades are projected to be largely met by growth of aquaculture. However, increased aquaculture production is linked to higher demand for natural resources and energy as well as emissions to the environment. This paper explores the use of Life Cycle Assessment to improve knowledge of potential environmental impacts of future aquaculture growth. Different scenarios of future aquaculture development are taken into account in calculating the life cycle environmental impacts. The environmental impact assessments were built on Food and Agriculture Organization statistics in terms of production volume of different species, whereas the inputs and outputs associated with aquaculture production systems were sourced from the literature. The matrix of input-output databases was established through the Blue Frontiers study.

The Los Alamos General Circulation Model hydrologic cycle

As the global population has increased, so have human influences on the global environment. ... How can we better understand and predict these natural and potential anthropogenic variations? One way is to develop a model that can accurately describe all the components of the hydrologic cycle, rather than just the end result variables such as precipitation and soil moisture. If we can predict and simulate variations in evaporation and moisture convergence, as well as precipitation, then we will have greater confidence in our ability to at least model precipitation variations. Therefore, we describe here just how well we can model relevant aspects of the global hydrologic cycle. In particular, we determine how well we can model the annual and seasonal mean global precipitation, evaporation, and atmospheric water vapor transport.

Climatological aspects of the large-scale hydrologic cycle in the United States

We describe a 2.5-degree gridpoint atmospheric hydrology/climatology of precipitable water, precipitation, atmospheric moisture convergence, and a residual evaporation or evapotranspiration for the coterminous United States. We also describe a large-scale surface hydrology/climatology of a residual soil moisture, streamflow divergence, or runoff, as well as precipitation and evaporation. Annual and seasonal means and interrelationships among various components of the hydrologic cycles are discussed.