Investigation of taste tainting in salmon flesh in the Ribble catchment

This report presents the findings of the first phase of an investigation into the cause(s) of taints in salmonid fish in the River Ribble, commissioned by the North West Region of the Environment Agency. There have been reports of tainting in fish taken from both the estuary and the freshwater river for many years, but the contaminants involved and their source and transport pathway are unknown. Tainting by phenols has been of specific concern in the past. The work programme comprised: examination of tainting reports; collection of salmonids; their submission for taste testing; literature review; analysis of fish flesh using gas chromatography-mass spectrometry (GCMS) and analysis of river bed sediments. From enquiries, three common descriptors of the 'taint' were identified: disinfectanty; diesely; and muddy. The incidence of taints appears transient/irregular and may therefore relate to the incidence of discharges and specific threshold concentrations of pollutants. The literature review showed that a wide range of organic compounds including many industrial chemicals, and others which are naturally occurring, can taint fish flesh. Taste testing confirmed the presence of tainted salmon and trout in the Ribbie Catchment. It identified a low incidence of 'untainted' fish but demonstrated the 'taint' to be not specific to one tainting substance. Differences were found both between the species and fish from different parts of the catchment. Overall, most fish exhibited an unpleasant flavour, though this may have been influenced to some extent by the fact that most were sexually mature. The worst tainting was found in trout from the river Calder: a soapy/chemical aftertaste. An unpleasant earthy/musty flavour distinguished the salmon from the trout. Phenol was shown to have been a minor issue during the present study, whilst no hydrocarbon taints were identified. Examination of tissue from the eight salmon exhibiting the worst taints revealed the presence of aromatic hydrocarbons, but no phenolic compounds. Other notable substances present in the fish were siioxanes and benzophenone. Data from sediment analysis is presented which shows the main compounds present to be aromatic and polyaromatic hydrocarbons, that concentrations at two locations R. Darwen and R. Calder were significantly higher than at other sites, and that some phenolic compounds were detected at low levels. A paucity of fish flesh taste descriptors linked to specific compounds prevented an obvious correlation to be made between the tastes observed and the organic compounds detected. Descriptors frequently used by the taste testing panel (e.g. earthy, musty, astringency, chemical) cannot be linked to any of the compounds identified in the tissue analyses. No taste information was available from the literature on siioxanes. Aromatic hydrocarbons though present in tissue and sediments were not identified as tainting.

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.

Effects of trawling for ocean shrimp (Pandalus jordani) on macroinvertebrate abundance and diversity at four sites near Nehalem Bank, Oregon

Surveys with a remotely operated vehicle (ROV) at four mudhabitat sites with different histories of ocean shrimp (Pandalus jordani) trawling showed measurable effects of trawling on macroinvertebrate abundance and diversity. Densities of the sea whip (Halipteris spp., P<0.01), the flat mud star (Luidia foliolata, P< 0.001), unidentified Asteroidea (P<0.05), and squat lobsters (unidentified Galathoidea, P<0.001) were lower at heavily trawled (HT) sites, as was invertebrate diversity based on the Shannon-Wiener index. Sea cucumbers (unidentified Holothuroidea) and unidentified corals (Hydrocoralia) were observed at lightly trawled (LT) sites but not at HT sites. Hagfish (Eptatretus spp.) burrows were the dominant structural feature of the sediment surface at all sites and were more abundant at the HT sites (P<0.05), a result potentially related to effects from fishery discards. Substantial heterogeneity was found between the northern and southern site pairs, indicating high site-to-site variability in macroinvertebrate densities in these deep (146–156 m) mud habitats. Two of the study sites were closed to trawling in June 2006. The data from this study can be used in combination with future surveys to measure recovery rates of deep, mud, seaf loor habitats from the effects of trawling, thus providing a critical piece of information for ecosystem-based management.

Sensitivity of angler benefit estimates from a model of recreational demand to the definition of the substitute sites considered by the angler

Fishery managers are mandated to understand the effects that environmental damage, fishery regulations, and habitat improvement projects have on the net benefits that recreational anglers derive from their sport. Since 1994, the National Marine Fisheries Service (NMFS) has worked to develop a consistent method for estimating net benefits through site choice models of recreational trip demand. In estimating net benefits with these models, there is a tradeoff between computational efficiency and angler behavior in reality. This article examines this tradeoff by considering the sensitivity of angler-welfare estimates for an increase in striped bass (Morone saxatalis) angling quality across choice sets with five travel distance cutoffs and compares those estimates to a model with an unrestricted choice set. This article shows that 95% confidence intervals for welfare estimates of an increase in the striped bass catch and keep rate overlap for all distance-based choice sets specified here.

A database for the industrial trawl fishery of Cote d'Ivoire

Fishery statistics for the industrial trawl fishery of Cote d'Ivoire have been well documented since 1968. However, data processing has changed significantly with time and some of the data files have been lost. In 1997, the Centre de Recherches Oceanologiques d'Abidjan decided to retrieve and process all trawl data available from different sources. This paper gives an overview of the database covering the period 1968 to 1997 and describes its coverage, format, structure and use. The database was developed using MS ACCESS and is a powerful tool for storing information about this fishery, and for analysis of its dynamics over a period of 30 years.

Escalation in shrimp production in the Sierra Leone industrial fishery

Applying Turkey's jackknife method on MSY estimates from the surplus production models of Schaefer and Fox showed that the optimum yield for shrimps in industrial fishery in Sierra Leone is estimated at 2,686.8 t with 15,822 fishing days. Annual catch for 1996 was 2,788 t, indicating an escalation in exploitation which, if prolonged, could bring reduced productivity as experienced in the fishery some years ago.

The Irwell. Story of an industrial river

This is the Irwell: Story of an industrial river document produced by the North West Water in 1979. This report is a leaflet format document. It focuses on the historical evolution of River Irwell, since it was “born” the river Irwell, about three hundred million years ago when shallow seas covered most of south east Lancashire and Europe to present years. It looks at Irwell’s pollution, highlighting the Irwell’s lower stretches were some of the region was the most polluted due to the population growth and establishment of industrial activities i.e. Lancashire’s great cotton industry, breach and dye works, paper mills, tanneries, chemical and gas works. Wastes from these industries were discharged directly to the river, together with crude sewage from an ever increasing population. However over the years the condition of the Irwell was gradually improved.

The Cheshire Meres an analysis of data and a prioritisation of sites

This is a report on the Analysis of Data and a Prioritisation of Sites at the Cheshire Meres by the Institute of Freshwater Ecology. The report addresses data collected by the Agency for 24 basin sites in Cheshire. At least two samples were collected from each site, though not simultaneously. Sites were visited in May/June and in November. The determinands are standard and they included: water, temperature, conductivity, pH, DO, fractional white light penetration, TSS, chlorophyll, TP, ortho-phosphate, nitrate-, nitrite-, ammonium and silicate. Though concentrations were often higher than for other lakes in the region, rather exceeding criteria for classification as eutrophic lakes, the results confirmed that the series of lakes is, naturally, highly eutrophic and nothing in the present data differs so far from expectation that is persuasive that the ecosystems are reacting adversely to environmental stress. The data set is review and summarised, site-by-site, in an appendix. The grounds for prioritisation are discussed. Whether or not this preferred prioritised option is adopted, the Agency is recommended to review the way it carries out monitoring. The determinands and the sampling frequency need to be geared to the information that is required.

River Yealm SAP Consultation

This is the River Yealm Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Yealm Salmon Action Plan (SAP). This strategy represents an entirely new approach to salmon management within the UK and introduces the concept of river-specific salmon spawning targets as a salmon management tool. The River Yealm Salmon Action Plan follows the format of those completed for the rivers Tamar, Lynher, Tavy, Camel, Fowey and Plym. It is the final one of seven action plans that will be produced for salmon rivers managed by Cornwall Area. The River Yealm SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery. Notably there are potable water abstractions in the headwaters, workings for china clay on the main tributary, two inert waste landfill sites and an aggregate quarry adjacent to the main river and inputs from several Sewage Treatment Works (STW) and two industrial estates. The main River Yealm has been designated as River Ecosystem Class 1 for its water quality objectives. This is the highest water quality target set for rivers.