Age and Growth of the Butterfish, Peprilus tricanthus, in the Lower York River

In response to rapid population growth as well as to address the nutrient reduction goals for the Chesapeake Bay established by the Virginia Department of Environmental Quality (VDEQ), the Hampton Roads Sanitation District (HRSD) initiated the York River Treatment Plant (YRTP) Expansion Phase 1 project. The existing YRTP is a conventional step-feed activated sludge plant and is rated for an average daily design flow of 57 million liters per day (MLD). This project proposes to expand the existing treatment capacity to 114 MLD and to reduce the nutrients discharged to the York River, a tributary for the Chesapeake Bay. In order to meet the effluent limits set by the VDEQ, a treatment upgrade to limit of technology (LOT) or enhanced nutrient removal (ENR) was required. Malcolm Pirnie worked with HRSD and the VDEQ to develop and evaluate ENR process alternatives to achieve the required effluent limits with the goal of determining the most reliable and cost effective alternative to achieve the aggressive nutrient reduction goals. This paper will highlight the key issues in determining the most desirable treatment process considering both economic and non-economic factors.

Download Full-text

Age and growth pattern of the thin-lipped mullet Liza Ramada in the Eastern coast of Libya.

International Journal of Bioassays ◽

10.21746/ijbio.2016.06.007 ◽

2016 ◽

Vol 5 (06) ◽

pp. 4620

Author(s):

Manal M. Khalifa ◽

Ramadan A. S. Ali ◽

Abdalla N. Elawad* ◽

Mohammad El. ElMor

Keyword(s):

Frequency Distribution ◽

Age Groups ◽

Age Determination ◽

Age And Growth ◽

Eastern Coast ◽

Growth Equation ◽

Length Frequency Distribution ◽

Length Frequency ◽

Scale Reading ◽

Von Bertalanffy Growth Equation

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in Eastern coast of Libya. Aging was done by two methods: counting annuli on scales and by length frequency distribution, a total of 218 scales were studied for age determination, in addition of 334 fishes specimen for length frequency distribution reading. Four age groups were determined from scale reading, and five age groups from length frequency distribution methods, the parameters of the Von Bertalanffy growth equation for both sex of all individuals were estimated at 35.4 cm, 0.187 per year, -1.14 years and 2.4, for male were estimated at 35.7 cm, 0.17 per year, -1.367 and 2.3, for female were 38.6 cm, 0.156 per year, -1.383 and 2.4, for L∞, k and t0, and φ′, respectively.

Download Full-text