The half-lives of biological activity of some pesticides in water

In the absence of analytical methods, the half-lives of biological activity of pesticides can be estimated by bioassays. To determine the half-lives of biological acivity of pesticides to fish, static bioassays were conducted in the laboratory with ten different formulations of pesticides using Labeo rohita as a bio-indicator. The half-lives of biological activity for ten different pesticides in soft water at pH 7.5 and 27°C, ranged from 4.6 days to 11.8 days. The half-life of biological activity of Sumithion 50% EC was only 4.6 days. In contrast, Dimecron 50% EC degraded very slowly and its half-life of biological activity on L. rohita was about 11.8 days. Sumithion 50% EC, Padan 50% SP, EPN 45% EC, Diazinon 40% EC and Diazinon 10 G degraded in less than five to seven days indicating that these pesticides are desirable for rice-fish culture. Contamination by pesticides with long-term residual toxicity in waters may eventually cause high levels of fish mortality.

Global analysis of mRNA half-lives and de novo transcription in a dinoflagellate, Karenia brevis

Dinoflagellates possess many physiological processes that appear to be under post-transcriptional control. However, the extent to which their genes are regulated post-transcriptionally remains unresolved. To gain insight into the roles of differential mRNA stability and de novo transcription in dinoflagellates, we biosynthetically labeled RNA with 4-thiouracil to isolate newly transcribed and pre-existing RNA pools in Karenia brevis. These isolated fractions were then used for analysis of global mRNA stability and de novo transcription by hybridization to a K. brevis microarray. Global K. brevis mRNA half-lives were calculated from the ratio of newly transcribed to pre-existing RNA for 7086 array features using the online software HALO (Half-life Organizer). Overall, mRNA half-lives were substantially longer than reported in other organisms studied at the global level, ranging from 42 minutes to greater than 144 h, with a median of 33 hours. Consistent with well-documented trends observed in other organisms, housekeeping processes, including energy metabolism and transport, were significantly enriched in the most highly stable messages. Shorter-lived transcripts included a higher proportion of transcriptional regulation, stress response, and other response/regulatory processes. One such family of proteins involved in post-transcriptional regulation in chloroplasts and mitochondria, the pentatricopeptide repeat (PPR) proteins, had dramatically shorter half-lives when compared to the arrayed transcriptome. As transcript abundances for PPR proteins were previously observed to rapidly increase in response to nutrient addition, we queried the newly synthesized RNA pools at 1 and 4 h following nitrate addition to N-depleted cultures. Transcriptome-wide there was little evidence of increases in the rate of de novo transcription during the first 4 h, relative to that in N-depleted cells, and no evidence for increased PPR protein transcription. These results lend support to the growing consensus of post-transcriptional control of gene expression in dinoflagellates.

Proposed Environmental Quality Standards for Phenol in Water

This is the Proposed Environmental Quality Standards (EQS) for Phenol in Water prepared for the National Rivers Authority, and published by the Environment Agency in 1995. The report reviews the properties and uses of phenol, its fate, behaviour and reported concentrations in the environment and critically assesses the available data on its toxicity and bioaccumulation. The information is used to derive EQSs for the protection of fresh and saltwater life and for the abstraction of water to potable supply. Phenol is widely used as a chemical intermediate and the main sources for phenol in the environment are of anthropogenic origin. Phenol may also be formed during natural decomposition of organic material. The persistence of phenol in the aquatic environment is low with biodegradation being the main degradation process (half-lives of hours to days). Phenol is moderately toxic to aquatic organisms and its potential to bioaccumulate in aquatic organisms is low.

The Fisheries for Mangrove Cockles,Anadaraspp., from Mexico to Peru, With Descriptions of Their Habitats and Biology, the Fishermen’s Lives, and the Effects of Shrimp Farming

This paper provides the first description of the mangrove cockle, Anadara spp., fisheries throughout their Latin American range along the Pacific coast from Mexico to Peru. Two species, A. tuberculosa and A. grandis, are found over the entire range, while A. similis occurs from El Salvador to Peru. Anadara tuberculosa is by far the most abundant, while A. grandis has declined in abundance during recent decades. Anadara tuberculosa and A. similis occur in level mud sediments in mangrove swamps, comprised mostly of Rhizophora mangle, which line the main-lands and islands of lagoons, whereas A. grandis inhabits intertidal mud flats along the edges of the same mangrove swamps. All harvested cockles are sexually mature. Gametogenesis of the three species occurs year round, and juvenile cockles grow rap-idly. Cockle densities at sizes at least 16–42 mm long ranged from 7 to 24/m2 in Mexico. Macrofaunal associates of cockles include crustaceans, gastropods, and finfishes. The mangrove swamps are in nearly pristine condition in every country except Honduras, Ecuador, and Peru, where shrimp farms constructed in the 1980’s and 1990’s have destroyed some mangrove zones. In addition, Hurricane Mitch destroyed some Honduran mangrove swamps in 1998. About 15,000 fishermen, including men, women, and children, harvest the cockles. Ecuador has the largest tabulated number of fishermen, 5,055, while Peru has the fewest, 75. Colombia has a large number, perhaps exceeding that in Ecuador, but a detailed census of them has never been made. The fishermen are poor and live a meager existence; they do not earn sufficient money to purchase adequate food to allow their full health and growth potential. They travel almost daily from their villages to the harvesting areas in wooden canoes and fiberglass boats at low tide when they can walk into the mangrove swamps to harvest cockles for about 4 h. Harvest rates, which vary among countries owing to differences in cockle abundances, range from about 50 cockles/fisherman/day in El Salvador and Honduras to 500–1,000/ fisherman/day in Mexico. The fishermen return to their villages and sell the cockles to dealers, who sell them mainly whole to market outlets within their countries, but there is some exporting to adjacent countries. An important food in most countries, the cockles are eaten in seviche, raw on the half-shell, and cooked with rice. The cockles are under heavy harvesting pressure, except in Mexico, but stocks are not yet being depleted because they are harvested at sizes which have already spawned. Also some spawning stocks lie within dense mangrove stands which the fishermen cannot reach. Consumers fortunately desire the largest cockles, spurning the smallest. Cockles are important to the people, and efforts to reduce the harvests to prevent overfishing would lead to severe economic suffering in the fishing communities. Pro-grams to conserve and improve cockle habitats may be the most judicious actions to take. Preserving the mangrove swamps intact, increasing their sizes where possible, and controlling cockle predators would lead to an increase in cockle abundance and harvests. Fishes that prey on juvenile cockles might be seined along the edges of swamps before the tide rises and they swim into the swamps to feed. Transplanting mangrove seedlings to suitable areas might increase the size of those habitats. The numbers of fishermen may increase in the future, because most adults now have several children. If new fishermen are tempted to harvest small, immature cockles and stocks are not increased, minimum size rules for harvestable cockles could be implemented and enforced to ensure adequate spawning.

Environmental Studies of Monterey Bay and the Central California Coastal Zone : Progress Report: First Half of 2nd Year of Operation--July 1971-February 1972

PDF contains 94 pages.

Telling stories, understanding lives, working toward change

Stories are helping us learn more about the livelihoods of the fishers and farmers with whom we work in eastern India. We are engaged with these communities in processes and activities aimed at improving their lives and promoting changes in government policy and service delivery in aquaculture and fisheries. Stories are told in several languages by women and men who fish and farm, about their lives, their livelihoods and significant changes they have experienced. We also record stories as narrated to us by colleague-informants. The written and spoken word, photographs, drawings and films – all are used to document the stories of people’s lives, sometimes prompted by questions as simple as “What do people talk about in the village?” Through the power of language, stories can be an entry point into livelihoods programming, monitoring and evaluation, conflict transformation and ultimately a way of giving life to a rights-based approach to development. (PDF contains 10 pages).

Environmental Studies of Monterey Bay and Central California Coastal Zone. First half-year of operation, July 1970-February 1971

(PDF contains 141 pages)

Adapting to climate change: Combining economics and geomorphology in coastal policy

How is climate change affecting our coastal environment? How can coastal communities adapt to sea level rise and increased storm risk? These questions have garnered tremendous interest from scientists and policy makers alike, as the dynamic coastal environment is particularly vulnerable to the impacts of climate change. Over half the world population lives and works in a coastal zone less than 120 miles wide, thereby being continuously affected by the changes in the coastal environment [6]. Housing markets are directly influenced by the physical processes that govern coastal systems. Beach towns like Oak Island in North Carolina (NC) face severe erosion, and the tax assesed value of one coastal property fell by 93% in 2007 [9]. With almost ninety percent of the sandy beaches in the US facing moderate to severe erosion [8], coastal communities often intervene to stabilize the shoreline and hold back the sea in order to protect coastal property and infrastructure. Beach nourishment, which is the process of rebuilding a beach by periodically replacing an eroding section of the beach with sand dredged from another location, is a policy for erosion control in many parts of the US Atlantic and Pacific coasts [3]. Beach nourishment projects in the United States are primarily federally funded and implemented by the Army Corps of Engineers (ACE) after a benefit-cost analysis. Benefits from beach nourishment include reduction in storm damage and recreational benefits from a wider beach. Costs would include the expected cost of construction, present value of periodic maintenance, and any external cost such as the environmental cost associated with a nourishment project (NOAA). Federal appropriations for nourishment totaled $787 million from 1995 to 2002 [10]. Human interventions to stabilize shorelines and physical coastal dynamics are strongly coupled. The value of the beach, in the form of storm protection and recreation amenities, is at least partly capitalized into property values. These beach values ultimately influence the benefit-cost analysis in support of shoreline stabilization policy, which, in turn, affects the shoreline dynamics. This paper explores the policy implications of this circularity. With a better understanding of the physical-economic feedbacks, policy makers can more effectively design climate change adaptation strategies. (PDF contains 4 pages)

Design of a half ton dehydrator for fish

A half-ton capacity artificial dryer has been designed at the Central Institute of Fisheries Technology for drying fish like Mackerel, Sardine, White bait etc. The dryer is a hot air recirculation type. 80 KW thermostatically controlled heating coils are made use of for heating the air. The air is circulated by means of an axial flow pattern fan. Drying takes place at a temperature of 115 degrees F. The structure of the dryer comes to about Rs. 20,000.

Half the fishers in the world

Tracing the road ahead for women in fisheries in Asia, a continent that produces the most fish and supports the largest number of fishers in the world.