Recruitment of larval Atlantic menhaden (Brevoortia tyrannus) to North Carolina and New Jersey estuaries: evidence for larval transport northward along the east coast of the United States

Age, size, abundance, and birthdate distributions were compared for larval Atlantic menhaden (Brevoortia tyrannus) collected weekly during their estuarine recruitment seasons in 1989–90, 1990–91, and 1992–93 in lower estuaries near Beaufort, North Carolina, and Tuckerton, New Jersey, to determine the source of these larvae. Larval recruitment in New Jersey extended for 9 months beginning in October but was discontinuous and was punctuated by periods of no catch that were associated with low water temperatures. In North Carolina, recruitment was continuous for 5–6 months beginning in November. Total yearly larval density in North Carolina was higher (15–39×) than in New Jersey for each of the 3 years. Larvae collected in North Carolina generally grew faster than larvae collected in New Jersey and were, on average, older and larger. Birthdate distributions (back-calculated from sagittal otolith ages) overlapped between sites and included many larvae that were spawned in winter. Early spawned (through October) larvae caught in the New Jersey estuary were probably spawned off New Jersey. Larvae spawned later (November–April) and collected in the same estuary were probably from south of Cape Hatteras because only there are winter water temperatures warm enough (≥16°C) to allow spawning and larval development. The percentage contribution of these late-spawned larvae from south of Cape Hatteras were an important, but variable fraction (10% in 1992–93 to 87% in 1989–90) of the total number of larvae recruited to this New Jersey estuary. Thus, this study provides evidence that some B. tyrannus spawned south of Cape Hatteras may reach New Jersey estuarine nurseries.

Upwelling, offshore transport, and the availability of rockfish in central California

EXTRACT (SEE PDF FOR FULL ABSTRACT): We used the diet of a seabird, the common murre (Uria aalge), nesting on Southeast Farallon Island and feeding in the Gulf of the Farallones, California, as an index to abundance of juvenile rockfish, then related fish abundance to indices of turbulence and upwelling over an 18-year period, 1973-1990. Strong, persistent upwelling or downwelling led to reduced availability of fish in the study area, in contrast to great abundance when upwelling was mild or pulsed. ... On the basis of our study, one effect might be that fishes thought strong enough to resist Ekman transport could be transported out of normal areas of recruitment.

Multiple-proxy lacustrine record of moisture transport over western North America from 24,000 to 12,000 YBP, Lake Estancia, New Mexico [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Pluvial Lake Estancia in central New Mexico experienced large and rapid fluctuations in surface area and elevation during the build-up to and termination of the last glacial maximum (LGM). Due to continuous groundwater discharge, a minimum pool covering about 400 square kilometers was maintained in the central basin until about 12,000 years ago, ensuring a continuous depositional sequence even during low stands of the lake. ... The sensitive response to fluctuations in climate by several independent proxies at Estancia show that transport of Pacific moisture over western North America changed dramatically during the last Ice Age, perhaps comparable to the large and rapid changes in climate documented from high-latitude ice and North Atlantic marine sediments for the LCM and its transitions.

Assessment of siltation rate and sediment transport in Bombay harbour based on Cesium-137 distribution

Low level aqueous radioactive wastes from the nuclear complex at Trombay are discharged into the Bombay harbour. Of the 6 principal radionuclides comprising the discharge, cesium-137 is most predominantly taken up by silt from the sea water. Isoactivity contours show that activity levels just off the point of discharge, and further south to Pir Pau, were between 50 and 100 pCi/g. Activity in the main channel of the harbour remained below 10 pCi/g, while further north (below the Thane Creek bridge) it was around 20 pCi/g. Activity in the top 6 cm of a core off Trombay naval jetty was <5 pCi/g, reaching a maximum of 178 pCi/g at 14cm below the surface. Thereafter, it tapered off to 5 pCi/g down to a metre.

Techniques for the transport and maintenance of scleractinian coral

Several small scleractinian coral colonies were collected from a remote reef and transferred [to] the Louisiana Universities Marine Center (LUMCON) for in vitro reproductive and larval studies. The species used here were Porites astreoides and Diploria strigosa. Colony size was ~20 cm in diameter. Colonies were brought to the surface by liftbag and stored in modified ice coolers. They were transported from Freeport, TX to Cocodrie, LA by truck for nearly 15 hours where field conditions were simulated in waiting aquaria. This document describes the techniques and equipment that were used, how to outfit such aquaria, proper handling techniques for coral colonies, and several eventualities that the mariculturist should be prepared for in undertaking this endeavor. It will hopefully prevent many mistakes from being made.

Infrastructure facilities for deep-sea and off-shore fishing

The author presents a brief account of the infrastructure facilities required for the fishing industry. He describes those facilities presently available in Sri Lanka, and those that are under construction, and gives a few suggestions indicating the nature of infrastructure facilities that are vital to the local situation at its present stage of development. The principal facilities discussed are (1) fish landing places; (2) unloading handling facilities; (3) vessel servicing facilities; and (4) navigation aids.

Financial assistance for purchase of large fishing vessels

The Government of Sri Lanka is improving off-shore and deep-shore fishing by introducing more sophisticated and larger vessels into the Sri Lanka waters, together with the offer of subsidies, tax holidays and other concessions to those who seek to operate such fishing vessels. As a first step, some thirty 38 foot class fishing vessels are to be introduced. The requisite variety and quantity of fishing gear is supplied together with the vessels, and operators will be given further assistance to either export or market their catches locally by provision of insulated fish transport vans, jeeps with trailers, crushed ice plants, fish storage cabinets and adequate spares for at least the next few years. A description is given of the credit terms offered for the purchase of such vessels, pre-shipment finance, and loans and hire purchase facilities.

Tracing sediment transport and bed regime in Nha Trang Bay

Three spatial structure groups of radionuclides in U and Th series, 210Pb-excess and 137Cs, and 40K were found based on analyzing temporal and spatial datum of their content by factor analysis with oblique rotation in Nhatrang bay. U and Th spatial structure with their contours decreased toward the offshore, ran longshore and divided seawater of bay into two parts with strong gradient on both sides. Inside part located from center of Nhatrang bay toward the seashore with three main deposit centers of their contents higher than 23 Bq/kg.dry for 238U and 40 Bq/kg.dry for 232Th, indicated unstability of shoreline. Almost sediments coming from river extended toward the offshore, were stopped and transported toward southeastern. The outside part was less than above mentioned content. The boundary line between two parts superposed with the constantly limit line of turbid plume in the rainy season. Direct influence of the continental runoff was limited by the 9 Bq/kg.dry contour of 238U, 19 Bq/kg.dry contour of 232Th. Longshore current was a predominant process whereas lateral transport as sifting and winnowing process of finer grains in sediments of Nhatrang bay. Areas that had very low content of 137Cs and 210 Pb-excess adjoining shoreline showed areas being eroded. Accumulation of 137Cs and 210 Pbexcess nearby river mouth characterized for fine compositions of sediments controlled by seasonal plumes and sites further toward the south indicated finer materials transported from river and accumulated in lack of hydrodynamic process. Near shore accumulation of 40K revealed the sediments there originated from bed erosion.

Viability of Penaeus monodon eggs after simulated transport conditions

P. monodon spawners, transported from maturation pens suffer from stress which in turn may lead to lowered spawning rate or fertility. Spawning the females in the maturation site and transporting the eggs to the hatchery site is being considered as an alternative. Egg transport costs may be reduced to a minimum by using eggs from ablated spawners, transported at high density with no aeration. Experiments on higher egg densities as well as on transport of nauplii should, however, be undertaken.

Transport of sugpo, Penaeus monodon juveniles

This study was made as an attempt to investigate the optimum packing density and the ice quantity suitable for the transport of Penaeus monodon juveniles. The results revealed that prawns of 40 mg size can be packed to as much as 3,000 per bag. While packing densities above 3,000 per bag containing 8 L seawater and 16 L oxygen can be used only for short transport periods. On the other hand in the ice-quantity experiment, mortality rate was less than 1% in all the bags containing 300 g, 600 g, 900 g and 1200 g of ice. A packing temperature of 20~’C must be maintained hence, 50 g of ice per hour should be allowed per box, counting from the moment the box is sealed to the time it is estimated to be opened.

Improved facilities for marine biology in East Africa

In 1967 the then University College of Dar es Salaam built a small laboratory on the shore at Kunduchi, 16 km from the main campus and 24 km north of Dar es Salaam. This was used for undergraduate field courses, and as a base for staff from the University to carry out research. It soon became apparent that the urgent need for studies of the marine environment in the East African area, and the lack of existing facilities, necessitated the development of the Kunduchi Marine Biology station into a research establishment with its own staff of full time scientists. This operation began in 1970: necessary structural modifications have been made to the building, staff have been recruited, and the station has been equipped with an adequate range of field and laboratory apparatus. A varied programme of research is now actively under way.