Progress report on fish counting on the Rivers Itchen and Test

This progress report summarises work on NSHEB Mark 10 fish counters which are installed at Woodmill on the River Itchen and Nurseling Mill and Connegar Bridge on the River Test. Counters are evaluated and salmon behaviour regarding the counters examined. The report includes a a list of equipment needed for the efficient running of the project in the future.

The effects of environmental stress on the physiology of growth in rainbow trout, Salmo gairderi Richardson

There is little doubt that both mammalian and teleost growth hormones can accelerate growth and increase food conversion efficiency in all commonly-reared species of salmonid fish. In those vertebrates that have been closely studied (predominantly mammals), the pituitary hormone somatotropin (GH or growth hormone) is a prime determinant of somatic growth. The hormone stimulates protein biosynthesis and tissue growth, enhances lipid utilization and lipid release from the adipose tissues (a protein-sparing effect) and suppresses the peripheral utilization of glucose. The present study is a prerequisite for future work on growth hormone physiology in salmonids and should contribute to our understanding of the mechanisms of growth suppression in stressed fish. Plasma growth hormone (GH) levels were measured in rainbow trout using a radioimmunoassay developed against chinook salmon growth hormone.

Oxygen flux through salmonid spawning gravels

Laboratory and field studies have shown that the survival of salmonid fish eggs and alevins is dependent upon the supply rate or flux of dissolved oxygen through gravel beds used for spawning. Although there have been a number of studies concerned with North American species there are few data for Atlantic salmon (Salmo salar) and the brown trout (S. trutta). For this study intragravel seepage velocities and dissolved oxygen concentrations have been measured throughout the incubation period in spawning gravels utilized by brown trout (Salmo trutta). Variation in the hatching success of batches of trout and salmon (Salmo salar) can, in part, be attributed to a critical threshold of oxygen flux through the gravels.

The effects of a sand layer upon swim-up success in UK salmonids

There are two main ways in which gravel composition and changes therein arising from siltation, can influence the survival of young salmonids. First, the composition of the gravel will affect its permeability and, hence, may influence the survival of eggs and alevins through its effect upon the rate of supply of oxygen and the rate of removal of metabolic products. Second, the composition of the gravel may affect the ease, or otherwise, of emergence at the time of swim-up and alevins may become trapped in the gravel and perish. This aspect is the main concern of the present report. Experiments were conducted to examine the effects upon fry emergence of a sand layer deposited on the gravel surface. The study concludes that fry of brown trout and Atlantic salmon emerged through layers of sand up to 8 cm thick but the percentage emergence, even from the controls with no sand, was relatively low (5 - 68%). There was no firm evidence that the experimental treatments influenced percentage emergence, timing of emergence or weight of fry at the time of emergence.

The production of freshwater fish for food

It has been estimated that in England and Wales fresh water covers some 340 square miles of which about one quarter is inhabited mainly by salmon and trout; in Scotland the lakes cover an area of 340 square miles. The principal object of this publication is to make available in handy form some of the methods, especially those involving the use of manures, by which crops of fish from water can be increased. The cultivation of water which this implies may be compared directly to the cultivation of farm land: the conditions for growth are made as favourable as possible, the seed is sown in the form of young fish, and after one or perhaps two growing seasons the crop is harvested. There are however many waters about the country where marketable fish are already available and can be removed without prejudice to, and indeed to the advantage of, sporting fisheries. In such cases it is necessary only to remove the fish and to rely on the natural processes of reproduction of those which are left to repopulate the water. Farming waters in the true sense is the concern of the greater part of this publication; the removal of crops of otherwise unwanted fish is considered in the last two sections on perch trapping and eel fisheries.

Symposium on World tuna fisheries: commemorating the 50th anniversary of the establishment of the Inter-American Tropical Tuna Commission

The Inter-American Tropical Tuna Commission (lA TTC) came into existence in 1950, after its convention, signed by representatives ofCosta Rica and the United States in 1949, was ratified. It was the first international tuna organization, and only the third international fisheries organization, whose staff has had the responsibility for performing scientific research, the others being the International Pacific Halibut Commission, established in 1923, and the International Pacific Salmon Fisheries Commission, established in 1937. The current members of the IATTC are Costa Rica, Ecuador, EI Salvador, France, Guatemala, Japan, Mexico, Nicaragua, Panama, the United States, Vanuatu, and Venezuela. The first Director ofthe IATTC was Dr. Milner B. Schaefer, who was in that position from 1950 to 1963. He was followed by Dr. John L. Kask (1963-1969), Dr. James Joseph (1969-1999), and Dr. Robin L. Allen (1999-present). The success ofthe IATIC showed that it was possible to carry out research and management on an international, high-seas fishery successfully. Since then other international organizations for tuna management, including the International Commission for the Conservation of Atlantic Tunas (1969), the Forum Fisheries Agency (1979), the Commission for the Conservation of Southern Bluefin Tuna (1994), and the Indian Ocean Tuna Commission (1996), were established. Appropriately, the 50th anniversary celebration was held in Costa Rica, one of the two charter members of the IATTC. Persons who have held important positions in international fishery management in various parts ofthe world spoke at the celebration. Their presentations, except for that describing the Indian Ocean Tuna Commission, are reproduced in this volume.

Report upon the commercial fisheries in the Lancashire River Authority Area and their effect upon rod angling and spawning stock in the rivers and particularly the River Lune

The stock of salmon in any river is largely dependent upon the escapement of sufficient fish to ensure that an adequate quantity of ova is deposited and full use is made of all suitable spawning areas. At the present time, no accurate information is available on the numbers of fish entering rivers. Therefore, catch returns provide valuable information on fish stocks. This report summarises the catch returns for salmon in the Lancashire River Authority in the North of England for the years 1960-1964. Rivers included are the Lune, Ribble, Kent, Leven and Duddon.

The juvenile salmonid populations of the River Lune catchment, 1981 to 1985

The aim of this study was to assess the status of the juvenile salmonid populations of the River Lune and its tributaries. There was special emphasis on juvenile salmon stocks in view of the implementation of a net limitation order in 1980. The number of licensed instruments were reduced as follows: (1) Drift, hang or whammel nets - from 12 to 10 (2) Draft or seine nets - from 3 to 1 (3) Heave or haaf nets - from 4 6 to 2 6 For the purpose of this report, the River Lune system has been divided into 13 subcatchments and these are examined with a view to detecting any trends in the data such as subcatchment productivity, partitioning between salmon and trout nursery streams, and whether the restrictions on salmon fishing had any discernible effects on juvenile salmon productivity. The effect of flow and instream obstructions on salmonid densities are also investigated as these have been shown to be important factors affecting abundance. Throughout the study period a programme of enhancement stocking took place primarily with salmon ova and fry. The possible impact of this on the results of the surveys has been assessed. The distribution and abundance of juvenile salmon was found to be relatively consistent in each of the 13 subcatchments studied over the 1981-1985 period.

A summary report on juvenile salmonid populations of the River Lune catchment, 1981 to 1991

This report summarises the fisheries electrofishing survey work undertaken on the River Lune, England, in the period 1981-85 and 1991. As part of a long term monitoring programme by the National Rivers Authority, juvenile surveys, with the emphasis on salmonids, have been carried out on the River Lune on a number of occasions since 1981. The latest survey in 1991 now gives the opportunity to assess what, if any, changes have occurred in the juvenile populations across the last 11 years and how future fisheries management may impact on the River Lune as a fishery. The areas of trout and salmon, fry and parr production will be considered in detail, as will adult trout populations. Water quality issues will be mentioned briefly as will habitat issues, where they are deemed to be important in affecting fish densities.

River Lune juvenile fish stock assessment 1997 with particular reference to salmonids

This report presents data from the juvenile salmonid fish stock assessment which is part of the routine Environment Agency riverine monitoring programme. A total of 110 sites was electrofished throughout the Lune catchment between 15th July 1997 and 14th October 1997. These sites included 84 that had been previously sampled in the last comprehensive survey of the catchment, in 1991. The aim of this survey was to assess the distribution and abundance of juvenile salmon and trout in the River Lune catchment and to compare results with those of previous surveys.

Tracking migratory salmonids

The River Ribble drains into the Irish sea on the West coast of England. The estuary is approximately 20Km long, tunnel shaped, tapering from a 100m width at Preston dock to 5 km at Lytham where it enters the sea. This is a preliminary report on a study of oxygen requirements of Atlantic salmon (Salmo salar)and sea trout (Salmo trutta) in an estuary. Oxygen sending transmitters attached to fish were used to determine exposure of individuals to different dissolved oxygen concentrations as they moved in from the sea through the estuary of the River Ribble. This estuary is subject to extreme variations in dissolved oxygen concentrations. This report is based on the latest transcription and analysis of data completed in October 1983. The aim of this report is to give an overview of the work done and conclusions which are apparent at this stage.

An analysis of the historical catch data from the migratory salmonid fisheries of the River Ribble

The Ribble catchment is the largest and most diverse river system within National Rivers Authority (NRA), North West's Central Area. The river is approximately 100km in length and rises in a limestone area west of the Pennines. This report examines changes in the size and composition of the salmon and sea trout catches from the Ribble migratory salmonid fisheries during the years 1937 to 1991. Comparisons are made between the rod and net fisheries for both salmon and sea trout of the Ribble and Hodder. Patterns of catches shown by the Ribble fisheries are compared with those of other individual rivers and with patterns for the North West Region as a whole. An attempt is made to identify if any relationship exists between catch and stock abundance. Catch patterns shown by the Ribble and Hodder salmon fisheries are compared with electronic resistivity counter data from the two rivers. Annual salmon catch patterns and redd count data are compared both locally and regionally. Recommendations for future studies are made in the light of the report's findings.

The proposed Lune net limitation order 1999 and associated byelaws

The River Lune rises in the hills around Tebay in thje North of England and runs through rural farming country to Morecambe bay. It is generally considered as a river of high purity and unspoiled nature. The salmon fishery was at one time considered amongst the best in England and Wales, with very high catches to both rod and net fishermen. During the late 1960's the disease UDN decimated the stock. Since then there has been a recovery of the stock, but this is considered by most anglers and netsmen to be a partial recovery of some of the previous stock components. In recent years anglers and netsmen have voiced their concerns over the Lune stock and have lobbied for action to improve the Lune fishery. This net limitation order (NLO) and the separate byelaw in conjunction with habitat improvement are proposed as part of the strategy for future conservation and management of this salmon fishery. The fishery is currently exploited by 37 licensed netsmen, the highest number of any single estuary in England and Wales. There are 26 haaf, 10 drift and 1 seine nets available. Current estimates of the rod fishery are that 1100 to 1400 anglers fish 14 000 days per year. The River Luhe is one of the few rivers within England and Wales that has the benefit of an accurate fish counter. The counter is at Forge Weir approximately 4 km upstream of the tidal limit. The counts, together with records of the catches from the rod and net fishery, enable a reasonably accurate assessment of both rod and net exploitation. Extensive surveys of the juvenile population, carried out in 1991 and 1997, provide additional information. The purpose of this document is to describe and explain the current state of the salmon population in the River Lune and in doing so, demonstrate the current need for stock conservation. A second purpose is to demonstrate that the proposed NLO and byelaw package should allow the salmon population to reach its conservation target (spawning escapement target).

Fish pass design - criteria for the design and approval of fish passes and other structures to facilitate the passage of migratory fish in rivers

Many of British rivers hold stocks of salmon (Salmo salar L.) and sea trout (Salmo trutta L.) and during most of the year some of the adult fish migrate upstream to the head waters where, with the advent of winter, they will eventually spawn. For a variety of reasons, including the generation of power for milling, improving navigation and measuring water flow, man has put obstacles in the way of migratory fish which have added to those already provided by nature in the shape of rapids and waterfalls. While both salmon and sea trout, particularly the former, are capable of spectacular leaps the movement of fish over man-made and natural obstacles can be helped, or even made possible, by the judicious use of fish passes. These are designed to give the fish an easier route over or round an obstacle by allowing it to overcome the water head difference in a series of stages ('pool and traverse' fish pass) or by reducing the water velocity in a sloping channel (Denil fish pass). Salmon and sea trout make their spawning runs at different flow conditions, salmon preferring much higher water flows than sea trout. Hence the design of fish passes requires an understanding of the swimming ability of fish (speed and endurance) and the effect of water temperature on this ability. Also the unique features of each site must be appreciated to enable the pass to be positioned so that its entrance is readily located. As well as salmon and sea trout, rivers often have stocks of coarse fish and eels. Coarse fish migrations are generally local in character and although some obstructions such as weirs may allow downstream passages only, they do not cause a significant problem. Eels, like salmon and sea trout, travel both up and down river during the course of their life histories. However, the climbing power of elvers is legendary and it is not normally necessary to offer them help, while adult silver eels migrate at times of high water flow when downstream movement is comparatively easy: for these reasons neither coarse fish nor eels are considered further. The provision of fish passes is, in many instances, mandatory under the Salmon and Freshwater Fisheries Act 1975. This report is intended for those involved in the planning, siting, construction and operation of fish passes and is written to clarify the hydraulic problems for the biologist and the biological problems for the engineer. It is also intended to explain the criteria by which the design of an individual pass is assessed for Ministerial Approval.

The ecology and management of the European grayling Thymallus thymallus (Linnaeus). Interim report

The European grayling, Thymallus thymallus, is a highly under-rated freshwater fish, particularly in the United Kingdom. As such, little scientific research has been conducted on its biology, ecology or specific management plans, in comparison to the related species, salmon, Salmo salar L. and brown trout, Salm.o trutta trutta L. or the nearest relative to T. thymallus, the Arctic grayling, Thymallus arcticus (Walbaum), whose life history has been well documented in view of its high ranking by anglers, as a game fish. However, the importance of sound scientific research cannot be over stressed for this species, which can potentially provide an excellent fishery and source of income in salmonid depauparate rivers. The aim of this report therefore, is to review all available information on the biology, ecology and management of the European grayling, T. thymallus, incorporating findings for T. arcticus to bridge subjects where the literature is scarce, and propose management strategies for T. thymallus in the United Kingdom, bridge subjects where the literature is scarce, and propose management strategies for T. thymallus in the UK.