Problems with Unofficial and Inaccurate Geographical Names in the Fisheries Literature

Over a century of fi shery and oceanographic research conducted along the Atlantic coast of the United States has resulted in many publications using unofficial, and therefore unclear, geographic names for certain study areas. Such improper usage, besides being unscholarly, has and can lead to identification problems for readers unfamiliar with the area. Even worse, the use of electronic data bases and search engines can provide incomplete or confusing references when improper wording is used. The two terms used improperly most often are “Middle Atlantic Bight” and “South Atlantic Bight.” In general, the term “Middle Atlantic Bight” usually refers to an imprecise coastal area off the middle Atlantic states of New York, New Jersey, Delaware, Maryland, and Virginia, and the term “South Atlantic Bight” refers to the area off the southeastern states of North Carolina, South Carolina, Georgia, and Florida’s east coast.

Performance of genetically improved farmed tilapia (GIFT) under mono and mixed cui ture with silver barb (Barbodes gonionotus) in south-west Bangladesh

A participatory on-farm trial was carried out to evaluate the production performance of GIFT (genetically improved farmed tilapia) strain of Oreochmis sp., either alone or with silver barb (Barbodes gonionotus), in six rain-fed freshwater ponds of coastal area. There vvere two treatments; (i) GIFT alone at a stocking density of 24,700/ha (T1) and (ii) 1:1 combination of GIFT and silver barb (T1). Each of the treatments had three replications. A significantly (p

Methods of sensory evaluation of quality and application of statistical methods in sensory evaluation problems with special reference to fishery products

The quality of raw and processed fishery products depend on several factors like physiological conditions at the time of capture, morphological differences, rigor mortis, species, rate of icing and subsequent storage conditions. Sensory evaluation is still the most reliable method for evaluation of the freshness of raw processed fishery products. Sophisticated methods like Intelectron fish tester, cell fragility technique and chemical and bacteriological methods like estimation of trimethylamine, hypoxanthine, carbonyl compounds, volatile acid and total bacterial count have no doubt been developed for accessing the spoilage in fish products.

Problems in estimating the response functions of natural climatic recording systems [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): High-resolution proxy records of climate, such as varves, ice cores, and tree-rings, provide the opportunity for reconstructing climate on a year-by-year basis. In order to do so it is necessary to approximate the complex nonlinear response function of the natural recording system using linear statistical models. Three problems with this approach were discussed, and possible solutions were suggested. Examples were given from a reconstruction of Santa Barbara precipitation based on tree-ring records from Santa Barbara County.

Potential risks of contaminants with specific reference to mercury

Fresh water and fish are important to the people who live in the Lake Victoria region therefore the quality of the water and fish is of major importance (Johnson & Odada, 1996). It is well known that dirty water and spoilt fish can lead to poor health and lower standards of living, and that quality can be affected by the pollution in the environment. Even though Lake Victoria is very large, it is relatively shallow and the water remains in the lake basin for a long time (Bootsma & Hecky, 1993). There are a number of environmental issues in Lake Victoria, including water hyacinth~over-population and increased farming causing problems with the lake ecosystem. All these factors combine to keep contaminants within the lake for long time, which will lead to gradually increasing concentrations in the lake. Pollution is a term that covers a wide variety of chemicals and physical changes and their adverse effects on the environment. Here we focus on contaminants, which are unwanted chemicals introduced to the environment. Contaminants include a very wide variety of chemicals, both man-made and natural, for example, mercury, pesticides and herbicides, heavy metals, and natural plant and algae toxins. Many contaminants do not always lead to adverse effects immediately, but can gradually induce long-term problems leading to chronic illnesses and physical damage. A few contaminants have very rapid impacts resulting in immediately obvious changes such as death or injury. Sources of contaminants are varied. Contaminants can get in the lake by the way of agricultural treatment of crops near the lake, industrial effluent, intentional introduction such as fish poisoning byfishermen, natural sources such as heavy metals from particular types of rocks, and even some plants naturally release their toxins. Contaminant sources are not always found near Lake Victoria.

Effects of perturbations on estuarine microcosms

Microcosms containing planktonic communities from Chesapeake Bay responded to enrichment with sewage by developing larger standing crops of phytoplankton and zooplankton. Data suggest that increased productivity would be reflected up the food chain but might increase existing problems with dissolved oxygen and might lead to qualitative changes in the composition of the zooplankton. Either phosphorus or nitrogen was removed more rapidly from solution depending on where and when the experimental water was obtained. Increases in standing crop of algae were associated with loss of nitrogen from solution in two experiments and losses of both nitrogen and phosphorus from solution in one experiment.

T90-Steert: Letzte Untersuchungen vor der Übernahme ins EU-Regelwerk

After due consideration the EU Commission has decided in December 2005 to admit cod-ends made of netting turned 90 de-grees (T90) as an allowable alternative for the cod fishery of the Baltic. The construction was included as one of two admissibles versions into the newly issued EU regulation 2187/2005 on technical measures for the conservation of fishery resources of the Baltic. This contribution describes some of the investigations preceeding that decision with which some of the previous demurs could be dispelled. In the course of these experiments it was detected that the cod-end netting material plays an important role for the mesh selection of a T90 cod-end, whereas the netting twine diameter is negligible. Problems with modern twine mate-rial have to be taken in consideration for constructional changes of T90 cod-ends. A relation of 1 to 2 in the circumferences in meshes at the joining round between last row of the belly and extension/cod-end turned out to be acceptable. Both the hauling technique (sidetrawler or sterntrawler) and an extensive use in the commercial fishery proved to be of no relevance for to the selection of T90 cod-ends. Taken alone, the different hydrodynamic conditions in a cod-end are insufficient to fully explain the selection phenomena. This was demonstrates by the material-related differences in selectivity of T90 cod-ends.

Zum tierschutzgerechten Betäuben und Töten von Aal

Slaughtering of eels should be done not only under animal welfare aspects but as well under consumer protection and economical aspects with respect to technical feasibility. Methods must be practicable for enterprises slaughtering quantities of several kilograms up to several tons per day. Most methods applied up to now in whole Europe were (are) not in accordance with animal welfare mainly due to lacking prescriptions and alternative methods. The great number of experiments carried out within the frame of this project demonstrates the difficulties to combine optimal welfare demands with economical and technical fesibility aspects in one method. Measurements of EEG (electroencephalogram) and ECG (electrocardiogram) have shown that the method laid down in the german legislation does not perfectly stun all eels. This method was improved by applying a „prestun“ with 220 V for 1sec., followed by a 5 min phase at 45 V to prolongue the time of unconsciousness after the stun. Inflating nitrogen gas into the stunning bath additionally causes asphyxia during the stun. By this method 93% of the eels were stunned or even killed. Applying 220 V for bigger batches of eels (~400 kg) will cause big problems with the energy supply. Therefore this method is restricted to batches of 20 - 50 kg. The method laid down in the german legislation probably can be improved. Eels were stunned successfully without water, avoiding the problems of regional differences in the conductivity of the water. Other types of current and other frequencies and a combination of both should be tested as well as alternative electrode geometries also with respect to blood spots which occasionally occurred in the muscles preferably of bigger eels (>800 g). For the time being the method laid down in the german legislation is a reasonable compromise and under animal welfare aspects represents a considerable improvement.

The EC Water Framework Directive and its implications for the Environment Agency

The bulk of the European Community's water policy legislation was developed between the mid 1970s and the early 1990s. These directives addressed specific substances, sources, uses or processes but caused problems with differing methods definitions and aims. The Water Framework Directive (WFD) aims to resolve the piecemeal approach. The Environemnt Agency (EA) welcomes and supported the overall objective of establishing a coherent legislative framework. The EA has been discussing the implications of the WFD with European partners and has developed a timetable for the implementation and a special team will commission necessary research.

Electric fishing survey of the gravel addition sites on the River Wyre, Grizedale Beck and Joshua's Beck.

Although geographically the River Wyre lies between two rivers containing major migrations of adult salmon and sea trout, its rod & line fisheries have for a number of years produced exceptionally low catches. In order to determine the causes of this the Wyre Salmon and Sea trout Restoration Group (WSSRG) was conceived in 1994 as a partnership between the then National Rivers Authority (now Environment Agency), local landowners, angling clubs and interested parties. Two studies of 1994 and 1995 stated that there is a shortage of useable spawning gravels on the river. This is compounded by Abbeystead Reservoir acting as a gravel trap, the siltation of gravels on several side becks and problems with access to available gravels by returning adults. There was also perceived to be a need for accurate fishery data from the river encompassing redd counts, catch data and surveys of fry populations. The 1995 report suggested a number of management proposals which might be adopted in order to improve and create available spawning habitat for migratory salmonids. Funding was made available to create three spawning gravels on each of two side becks (Grizedale Beck and Joshua's Beck) and the addition of gravels to a site oh the main river below Abbeystead Reservoir. Modifications were also made to the fish pass at Abbeystead to allow easier passage of fish. These improvements were made in the autumn of 1995. Salmonid spawning redd counting was undertaken on the whole Wyre catchment in 1995/1996 and specific surveys by electric fishing on the gravel enhancement sites in the summer of 1996. This report details the current state of the improvement works that were undertaken and presents the results of electric fishing surveys in September 1996. A number of lessons have been learnt which will be of great benefit to the Fisheries Function in other parts of the Wyre catchment and the Central Area in general.

Degeneration of postovulatory follicles in the Iberian sardine Sardina pilchardus: structural changes and factors affecting resorption

Inaccuracy in the aging of postovulatory follicles (POFs) and in estimating the effect of temperature on the resorption rate of POFs may introduce bias in the determination of the daily spawning age classes with the daily egg production method (DEPM). To explore the above two bias problems with f ield-collected European pilchard (Sardina pilchardus, known regionally as the Iberian sardine), a method was developed in which the time elapsed from spawning (POF age) was estimated from the size of POFs (i.e., from the cross-sectional area in histological sections). The potential effect of the preservative type and embedding material on POF size and the effect of ambient water temperature on POF resorption rate are taken into account with this method. A highly significant loglinear relationship was found between POF area and age; POF area shrank by approximately 50% per day. POFs were also shown to shrink faster at higher temperatures (approximately 3% per degree), but this temperature effect is unlikely to be an important source of bias in the assignment of females to daily spawning classes. The embedding material was also shown to influence the size of POFs, the latter being significantly larger in resin than in paraffin sections. In conclusion, the size of POFs provides an indirect, reliable estimation of the time elapsed from spawning and may thus be used to test both the validity of POF staging criteria for identifying daily classes of spawners and the effect of other factors (such as temperature and laboratory processing) in applications of the DEPM to S. pilchardus and other fish species.

Marine reserves: they enhance fisheries, reduce conflicts, and protect resources

Marine fishery reserves, its fishery and non fishery benefits are discussed. Problems with marine fishery reserves are also pointed out.

High level of hybridisation in three species of Indian major carps

Thirty individuals of each species of Indian major carps, i.e., Catla catla, Cirrhinus cirrhosus (C. mrigala) and Labeo rohita, obtained from a nursery near Mymensingh, Bangladesh were analysed by means of allozyme electrophoresis. Twenty-one loci were studied. Several loci revealed significant deviation from Hardy-Weinberg expectations caused by deficiency of heterozygotes, indicating Wahlund effects due to problems with species identification. Moreover, bimodal distributions of individual heterozygosity within the three putative species indicated hybridisation. This was confirmed using analysis of individual admixture proportions, as individuals misidentified to species and hybrids between species were observed. Furthermore, factorial correspondence analysis to visualize genetic relationships among individuals revealed three distinct groups containing misclassified individuals, along with some intermediate individuals interpreted as hybrids. Ten per cent of all C. catla and L. rohita had been erroneously identified to species, and 40 per cent of all presumptive C. catla were hybrids between C. catla x C. cirrhosus and C. catla x L. rohita. In the case of C. cirrhosus, 37 per cent of the samples were C. cirrhosus x L. rohita hybrids. Thirty per cent of all presumptive L. rohita turned out to be hybrids between L. rohita x C. catla and L. rohita x C. cirrhosus. The high incidence of hybrids in C. catla might be responsible for slower growth of the fish in aquaculture.

South & West Cumberland Fisheries Advisory Committee 12th January, 1976.

This is the report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 12th January 1976. The report contains sections on land drainage representation on local committees, actions to be taken to solve problems with Braithwaite Weir, Enneralde compensation flow, fisheries activities report, recommendations for future policy by association hatcheries and progress made in implementing the recommendations contained in 'Taking Stock' publication. The section on fisheries activities reported by area fisheries officers looks at migratory fishing and spawning, U.D.N. disease appearance, poaching and prosecutions, biological work at Mockerkin Tarn and the River Calder. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Comparing autonomous underwater vehicle (AUV) and vessel-based tracking performance for locating acoustically tagged fish

Autonomous underwater vehicles (AUV’s) are increasingly used to collect physical, chemical, and biological information in the marine environment. Recent efforts include merging AUV technology with acoustic telemetry to provide information on the distribution and movements of marine fish. We compared surface vessel and AUV tracking capabilities under rigorous conditions in coastal waters near Juneau, Alaska. Tracking surveys were conducted with a REMUS 100 AUV equipped with an integrated acoustic receiver and hydrophone. The AUV was programmed to navigate along predetermined routes to detect both reference transmitters at 20–500 m depths and tagged fish and crabs in situ. Comparable boat surveys were also conducted. Transmitter depth had a major impact on tracking performance. The AUV was equally effective or better than the boat at detecting reference transmitters in shallow water, and significantly better for transmitters at deeper depths. Similar results were observed for tagged animals. Red king crab, Paralithodes camtschaticus, at moderate depths were recorded by both tracking methods, while only the AUV detected Sablefish, Anoplopoma fimbria, at depths exceeding 500 m. Strong currents and deep depths caused problems with AUV navigation, position estimation, and operational performance, but reflect problems encountered by other AUV applications that will likely diminish with future advances, enhanced methods, and increased use.