National Centers for Coastal Ocean Science Coastal Ecosystem Assessment Program: a manual of methods

Environmental managers strive to preserve natural resources for future generations but have limited decision-making tools to define ecosystem health. Many programs offer relevant broad-scale, environmental policy information on regional ecosystem health. These programs provide evidence of environmental condition and change, but lack connections between local impacts and direct effects on living resources. To address this need, the National Oceanic and Atmospheric Administration/National Ocean Service (NOAA/NOS) Cooperative Oxford Laboratory (COL), in cooperation with federal, state, and academic partners, implemented an integrated biotic ecosystem assessment on a sub-watershed 14-digit Hydrologic Unit Code (HUD) scale in Chesapeake Bay. The goals of this effort were to 1) establish a suite of bioindicators that are sensitive to ecosystem change, 2) establish the effects of varying land-use patterns on water quality and the subsequent health of living resources, 3) communicate these findings to local decision-makers, and 4) evaluate the success of management decisions in these systems. To establish indicators, three sub-watersheds were chosen based on statistical analysis of land-use patterns to represent a gradient from developed to agricultural. The Magothy (developed), Corsica (agricultural), and Rhode (reference) Rivers were identified. A random stratified design was developed based on depth (2m contour) and river mile. Sampling approaches were coordinated within this structure to allow for robust system comparisons. The sampling approach was hierarchal, with metrics chosen to represent a range from community to cellular level responses across multiple organisms. This approach allowed for the identification of sub-lethal stressors, and assessment of their impact on the organism and subsequently the population. Fish, crabs, clams, oysters, benthic organisms, and bacteria were targeted, as each occupies a separate ecological niche and may respond dissimilarly to environmental stressors. Particular attention was focused on the use of pathobiology as a tool for assessing environmental condition. By integrating the biotic component with water quality, sediment indices, and land- use information, this holistic evaluation of ecosystem health will provide management entities with information needed to inform local decision-making processes and establish benchmarks for future restoration efforts.

Assessment of Saurida tumbil (Bloch) stock in the northwest continental shelf water of India

Based on the data collected from New Ferry Wharf, Sassoon Dock and exploratory survey of MFV Saraswati on the Northwest coast of India, the growth, mortality, population and stock parameters of Saurida tumbil is reported in the present communication. The Von Bertalanffy growth function (GF) parameters for growth on length were found to be L∞=49.8 cm, K=0.96/year, t0 = -.141 year. The length at recruitment (lr) is 80 mm. (tr=.167 year) while the length at first capture (lc) for the commercial trawl fishery is 100 mm (tc=0.25 year). The annual fishing mortality coefficient (F) for 1983-85 was 0.43, the natural mortality coefficient (M) was 1.33 and the exploitation ratio (E) was 0.25. The yield per recruit (Y/R) attained the maximum of 54.99 g at F=1.091 for E=0.45 for the present tc at 0.25 year. The annual total stock (P) and standing stock (P) in the exploitation portion at the inshore grounds to a depth of about 50 m were estimated to be 12,811 tons and 6,034 tons respectively. The average annual yield of 2,635 tons at the present F=0.439 (E=0.247) was less than the maximum sustainable yield (MSY) for 3,331 tons attainable from the inshore grounds at E=0.45.

The characteristics of distribution and change of the seawater temperature and salinity of Cai river estuary and Northern Part of Nha Trang bay in the dry and rainy season

In this paper, some results of analyzing the hydrographic characteristics of the seawater temperature and salinity are presented. The received results showed that: in dry season, the influence of the Cai river water has is limited in Cai river estuary with the approximate transferable distance from the river mouth to the open sea of about 1 km. The isohaline 32%o could be defined as the separate boundary of the Cai river water; In rainy season, due to the river water discharges are high, the influence of Cai river water could be transferred to the open sea and island areas. The immerge of the Cai river water in the open sea areas in rainy season has changed the vertical structure of salinity and temperature in the northern part of Nhatrang bay. In both seasons, the Cai river water have influenced in the surface water layers 0 - 2m and the water layers deeper than 2m are influenced by the sea waters with the salinity of higher than 32%o.

Survival rates of different postlarval stages of Penaeus monodon Fabricius

The objective of this study is to determine survival rates of different postlarval stages upon stocking in the Leganes ponds. Twelve 3m x 2m x 2m suspension nets made of nylon cloth (mesh size = 0 . 1 mm) were set up in a Leganes Station pond (ave. water depth = 1 m) by means of 3-m long poles stacked at distances approximating the area of each net. The net bottom was filled with topsoil at least 15 cm thick to stimulate the pond bottom. At least 60 cm of the upper edge of each net was above the water level to prevent mixing of water inside and outside the net. P.monodon of stages P SUB-11 , P SUB-15 , P SUB-21 (from the hatchery) and P SUB-25 (from the wet lab) were stocked in the nets at 200/sq m or 1,200 fry/net. Due to lack of fry, only one P SUB-25 net was stocked. Each net had two large dried miapi branches as shelter from predation and cannibalism for the young sugpo fry. Fresh lablab was fed at the rate of one pail (approximately 5 kg) every four days per net. Harvest data show relatively higher survival rates for P SUB-15 and P SUB-18 compared to P SUB-11 and P SUB-25 with no significant difference between these two stages. The results for P SUB-25 may not be valid because the stock came from the wet lab in comparison to the other postlarval stages which were reared in the hatchery. Moreover, the P SUB-25 stock had no replicates and the net itself (no. 10) was discovered to have many holes. These preliminary results point to P SUB-15 as the best stage for harvest from the hatchery in terms of high pond recovery and lesser expense in rearing compared to older postlarvae.