Effects of El Niño events on energy demand and egg production of rockfish (Scorpaenidae: Sebastes): a bioenergetics approach

Fish bioenergetics models estimate relationships between energy budgets and environmental and physiological variables. This study presents a generic rockfish (Sebastes) bioenergetics model and estimates energy consumption by northern California blue rockf ish (S. mystinus) under average (baseline) and El Niño conditions. Compared to males, female S. mystinus required more energy because they were larger and had greater reproductive costs. When El Niño conditions (warmer temperatures; lower growth, condition, and fecundity) were experienced every 3−7 years, energy consumption decreased on an individual and a per-recruit basis in relation to baseline conditions, but the decrease was minor (<4% at the individual scale, <7% at the per-recruit scale) compared to decreases in female egg production (12−19% at the individual scale, 15−23% at the per-recruit scale). When mortality in per-recruit models was increased by adding fishing, energy consumption in El Niño models grew more similar to that seen in the baseline model. However, egg production decreased significantly — an effect exacerbated by the frequency of El Niño events. Sensitivity analyses showed that energy consumption estimates were most sensitive to respiration parameters, energy density, and female fecundity, and that estimated consumption increased as parameter uncertainty increased. This model provides a means of understanding rockfish trophic ecology in the context of community structure and environmental change by synthesizing metabolic, demographic, and environmental information. Future research should focus on acquiring such information so that models like the bioenergetics model can be used to estimate the effect of climate change, community shifts, and different harvesting strategies on rockfish energy demands.

The Demand for Eastern Oysters, Crassostrea virginica, from the Gulf of Mexico in the Presence of Vibrio vulnificus

California, in response to health concerns, initiated a program on 1 March 1991 which required anyone selling eastern oysters, Crassostrea virginica, from the Gulf of Mexico area to notify potential consumers that there was a risk in consuming them raw. This mandatory warning, followed shortly thereafter by a similar warning in other states, including Louisiana and Florida, received extensive press cover-age throughout the country and particularly in the Gulf area. This paper examines the extent to which the demand for Gulf-area oysters has been reduced as a result of mandatory warning labels and negative publicity. In general, the results suggest that since 1991 the “summer” dockside price has been reduced by about 50% as a result of warning labels and associated negative publicity, while the “winter” dockside price has been reduced by about 30%.

Trade secrets: a ten year overview of the illegal import of sea turtle products into the United States

For more than 25 years all sea turtle products have been prohibited from international commerce by the 170-member nations of the Convention on International Trade in Endangered Species (CITES). Sea turtles continue to be threatened by direct take (including poaching) and illegal trade despite multi-national protection efforts. Although take may contribute significantly to sea turtle decline, illegal take is difficult to measure since there are few quantified records associated with legal fisheries and fewer still for illegal take (poaching). We can, however, quantify one portion of the illegal sea turtle trade by determining how many illegal products were seized at United States ports of entry over a recent 10-year period. The United States Fish and Wildlife Service (USFWS) oversees the import and export of wildlife and wildlife products, ensuring that wildlife trade complies with United States laws and international treaties. Additionally, the USFWS has legal authority to target suspected illegal wildlife activity through undercover and field investigations. In an effort to assess the scale of illegal sea turtle take and trade, we have conducted a 10-year (1994 – 2003) review of the law enforcement database maintained by the USFWS. This database tracks the number and type of wildlife cases, the quantity of seized products, and the penalties assessed against violators. These data are minimum estimates of the sea turtle products passing through the United States borders, as smuggled wildlife is oftentimes not detected.

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.

Status of fish broodstock management and seed production in Bangladesh

The study was conducted with the broad objectives to assess the existing situation of broodstock management and fish seed production in private fish seed farms in Bangladesh. The data were collected from 100 private hatcheries and 40 nurseries in seven upazilas under four districts. There was no shed in forty hatcheries and the owners faced many problems. Brood fish ponds were found suitable for rearing brood fish. About 66% of the hatchery owners collected brood fish from their own ponds and ponds of neighboring areas. Activities like pond preparation; manuring and supplementary feeding were done properly but stocking density of brood fish in 76% of the hatcheries was 3,000-7,000 kg/ha. Infection of argulosis was found in brood fish of 87% of the hatcheries. About 67% of the hatchery owners practiced inter-species crossing. Major problems faced by the hatchery owners were argulosis of brood fish, unavailability of pure brood stock, inadequate brood fish pond. The hatchery owners were found interested to find out the preventive measures of argulosis, develop pure brood stock of indigenous carp and import pure strain of exotic carp. According to the nursery operators, they cultivated hybrid fry because of high demand, rapid growth and good taste. Problems of using hatchery spawn as mentioned by the nursery operators were inbreeding, under sized and aged brood stock, stunted growth, physical deformities and high mortality of spawn due to unknown causes.

Import substitution of combination wire rope. Part 1. Design, production and evaluation of a prototype combination wire rope

Model combination wire ropes with different covering materials were prepared and worked out specification for the prototype. A table model hand operated wire rope twisting machine was also developed for this. Prototype combination wire rope was twisted in collaboration with M/s South India Wire Ropes Ltd., Alwaye. Specification details, properties and field performance of the prototype studied are reported.

Import substitution of combination wire rope. Part 2. Production and standardisation of 17 mm dia combination wire rope.

The prototype combination wire rope (Cift-CWR 1) developed for deep sea trawling was further studied for improvement, optimisation of efficiency and standardization. A series of improved prototype combination wire ropes (Cift-CWR 2 to 6) were twisted and evaluated their mechanical properties and reported in this paper with recommendations for a standard 17mm dia combination wire rope of 6S (7C+8+1 Scr) + 6 Crs(6+1+1 Crc) construction.

Import substitution of combination wire rope. Part 3: Comparison of standard Cift-CWR and imported combination wire rope

Tensile and extension properties of standard Cift-CWR and imported combination wire ropes from Japan, Norway and Denmark are studied and the analysis is presented in the paper. Tensile and chemical properties of steel wire, tensile and abrasive properties of PP covering, effect of twist on material at different stages are worked out and reported.