Influence of the FSBI Small Research Grants scheme: an analysis and appraisal.

The FSBI Small Research Grants scheme has been running for 25 years, after its initiation during the Society's 25th Anniversary in 1992, while the Wyn Wheeler Grant for retired researchers was started during the 40th Anniversary year. Over this time some £560 000 has been awarded to researchers and it is argued that this has made a disproportionately positive contribution on fish research and researchers as evidenced by journal articles produced as a result of initial FSBI funding and the career trajectories of some recipients. These grants also reflect the international reach of the Society, and the increasing involvement of female researchers in fish research.

Valuing and understanding fish populations in the Anthropocene: key questions to address.

Research on the values of fish populations and fisheries has primarily focused on bio-economic aspects; a more nuanced and multidimensional perspective is mostly neglected. Although a range of social aspects is increasingly being considered in fisheries research, there is still no clear understanding as to how to include these additional values within management policies nor is there a cogent appreciation of the major knowledge gaps that should be tackled by future research. This paper results from a workshop held during the 50th anniversary symposium of the Fisheries Society of the British Isles at the University of Exeter, UK, in July 2017. Here, we aim to highlight the current knowledge gaps on the values of fish populations and fisheries thus directing future research. To this end, we present eight questions that are deeply relevant to understanding the values of fish populations and fisheries. These can be applied to all habitats and fisheries, including freshwater, estuarine and marine.

Comparing anadromous brown trout Salmo trutta in small, neighbouring catchments across contrasting landscapes: What is the role of environment in determining life-history characteristics?

Study of anadromous brown trout Salmo trutta in Orkney, U.K., burns (small streams) with a common-garden sea in Scapa Flow supports the key role of nutrient availability in fresh water, independent of day length, as a determinant of smolt age, with a systematic increase in mean smolt age from 1 to 3 years related inversely to productivity. Whole catchment (8 km2 ) population budgets indicated annual smolt production of around 650 individuals from approximately 100 spawners. Egg-to-smolt survival was 0·65%, while marine survival was estimated from mark-recapture to be between 3·5 and 10%. The question of B-type growth (accelerated growth immediately prior to or during smolt migration) was also addressed, with a strong negative correlation between B-type growth and size at end of winter suggesting that this represents a freshwater compensatory growth response. The data obtained indicate the potential importance of small catchments for supporting anadromous Salmo trutta populations and suggest that small runs of spawners (<100 individuals) are adequate to maintain stocks in such situations. Furthermore, they support the key role of freshwater productivity in determining life-history characteristics over small spatial scales, with Orkney providing a useful natural laboratory for future research into metapopulation genetic structuring and environmental factors at a tractable scale.

Antigenic and cross-protection studies of biotype 1 and biotype 2 isolates of Yersinia ruckeri in rainbow trout, Oncorhynchus mykiss (Walbaum).

AIMS: The study investigated antigen characteristics of biotype (bt) 1 and bt 2 isolates of Yersinia ruckeri. METHODS AND RESULTS: The cell surface characteristics of Y. ruckeri were compared for their antigenic characteristics using polyclonal antibodies that revealed that both biotypes had a homogenous whole-cell protein antigenic profile. Notable differences in the antigenic properties were observed in the lipopolysaccharide profile of both biotypes. Two iron-regulated outer membrane proteins (IROMP) of c.90 and 100 kDa were shown to be major specific antigens. The results demonstrate for the first time differences in antigens between bt 1 and bt 2 isolates of serotype O1 isolates of Y. ruckeri. The protection induced in rainbow trout by a commercial monovalent, and bivalent inactivated vaccine was tested with the outcome that the ability of isolates to cause mortality in vaccinated fish varied with geographical location. In this context, vaccination studies suggested that the O antigen was the dominant immunogenic molecule involved in protection against the disease. CONCLUSIONS: The O antigen of Y. ruckeri was the dominant immunogenic molecule involved in the protection of rainbow trout against enteric redmouth disease. SIGNIFICANCE AND IMPACT OF THE STUDY: There are distinct phenotypic and antigenic differences in Y. ruckeri bt 1 and bt 2 with O antigen recognized as the dominant immunogenic molecule. The data have significance in explaining the lack of success of the earlier monovalent vaccine and demonstrate the effectiveness of the newer bivalent vaccine.

Novel non-motile phenotypes of Yersinia ruckeri suggest expansion of the current clonal complex theory.

The biochemical and cell surface characteristics of 63 non-motile isolates of Yersinia ruckeri from various sources were compared using the API 20E rapid identification system and conventional phenotypic methods. Eight individual phenotypic groups from a variety of fish species were observed from the data set. Non-motile isolates were not exclusively observed from serogroup O1; membership of biotype 2 was recorded for representatives from serogroups O2-O7. Variations in phenotypes highlights that new clonal groups are arising and that the current typing scheme requires expansion. Previously, it was hypothesized that disease was caused by a few virulent clones; data in this paper suggests that this assumption is not the case. The lipopolysaccharide (O antigen) type in the non-motile biotype was different from other isolates of Y. ruckeri.

Efficacy of in-feed probiotics against Aeromonas bestiarum and Ichthyophthirius multifiliis skin infections in rainbow trout (Oncorhynchus mykiss, Walbaum).

AIMS: The aim of this study was to assess the efficacy of in-feed probiotics as a preventive measure against skin infections caused by Aeromonas bestiarum and Ichthyophthirius multifiliis (Ich) in rainbow trout. METHODS AND RESULTS: Fin rot was induced in fish by intradermal injection with 0.1 ml volumes containing 10(5) cells per ml A. bestiarum at the base of the dorsal fin. Ich infections resulted from immersion in Ich-contaminated water. Each probiotic was administered orally [10(8) cells per g feed for GC2 (Aeromonas sobria) and 10(10) cells per g feed for BA211 (Brochothrix thermosphacta)] for 14 days. Results showed that, after challenge with A. bestiarum, probiotics GC2 and BA211 led to 76% and 88% survival, respectively, in contrast to 22% survival for controls. Fish fed with probiotic GC2 had 100% survival after challenge with Ich compared with 2% for probiotic BA211 and 0% for controls. Analysis of innate immune responses revealed that probiotic GC2 promoted higher phagocytic activity, whereas probiotic BA211 led to enhanced respiratory burst activity. CONCLUSION: Of the two probiotics examined, GC2 was more effective in protecting against both fin rot and Ich. Each probiotic appeared to stimulate different pathways within the innate immune system. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first demonstration that probiotics can protect fish against surface infections. Furthermore, this is the first time a probiotic has been shown to protect against a eucaryotic pathogen, namely I. multifiliis.

Colonisation and extinction in relation to competition and resource partitioning in acanthocephalans of freshwater fishes of the British Isles.

This paper challenges two paradigms long held in relation to the ecology of parasites in freshwater systems: (1) autogenic species are poorer colonisers than allogenic ones; and (2) parasites with direct life cycles are more successful colonisers than those with complex life cycles. Using new and existing data for Acanthocephala in freshwater fish from the British Isles, it is suggested that all six species present have been able to colonise and persist successfully, in spite of the supposed limitations of their autogenic life-style. It is proposed that these parasites have overcome these limitations by a variety of means, which apply equally to all species considered. Foremost among these is the utilisation of a migratory fish host as either a preferred or a suitable host in their life cycle, allowing colonisation of new areas and rescue effects in established areas, whilst equally important is the use of a common and widespread crustacean as the intermediate host. In addition, all six species appear to exhibit resource partitioning by host at either or both the larval and adult stages, thus reducing the potential for competition and further facilitating colonisation and survival. This hypothesis is supported by data from previous studies both on acanthocephalans from Europe and North America and on other autogenic parasites. It also provides an explanation for the apparently atypical host utilisation patterns of some acanthocephalan species in areas on the edge of their distributions, notably in Ireland.

Gill protein turnover: costs of adaptation.

Measurements of gill protein synthesis, and hence turnover, were greatly facilitated over the last decade by the application of "flooding dose" methodology to non-mammalian species. Numerous studies show that in fish and aquatic invertebrates, gills are among the most active tissues with respect to protein turnover, this being true under a variety of environmental and nutritional conditions. The main components being turned over in fish gills are probably collagen, primarily in the gill arches, and epithelial cell proteins in the filaments, both arches and filaments having similar protein synthesis rates. Intriguingly, differences are apparent between protein synthesis rates of adjacent holobranchs, the first (most anterior) being significantly more active than the second or third, perhaps hinting at functional differences between holobranchs. Experimental estimates of energetic costs for protein synthesis, derived from cycloheximide treatment of isolated perfused gills, give a maximum value of 14 mmol O2/g protein synthesized, which is about double theoretical costs. Environmental stressors, such as heavy metals or acid/aluminum, have variable effects on branchial protein turnover. Limited data suggest that zinc or acid exposure depresses protein synthesis, whereas acid/aluminum increases it quite markedly. Calculations indicate that whereas effects within the gills may be substantial, in terms of whole animal energetics, the costs of branchial adaptation are likely to be small.

Changes in tissue and plasma free amino acid concentrations after feeding in Atlantic cod.

Atlantic cod, Gadus morhua, were maintained on a diet of sandeel and after a 6-day fast were refed a single meal. Concentrations of free amino acids (AAs) were measured in hepatic portal and cardiac blood as well as in the stomach and white muscle at intervals of 6h up to 24h post-feeding. The appearance of both essential and non-essential AAs in the hepatic portal blood was significantly correlated, up to 12h after feeding, to their abundance in the diet. There was a significant decline in total AA concentration in cardiac blood after 6h, followed by a significant increase at 12h. No significant changes in total AA concentration were observed in the other tissues, although mean concentration increased at 12 or 18h. At a more detailed level, the post-prandial changes in concentration of some essential AAs were consistent with their having a role in the stimulation of protein synthesis after feeding.

The effect of short-term fasting and a single meal on protein synthesis and oxygen consumption in cod, Gadus morhua.

Rates of protein synthesis and oxygen consumption (MO2) in cod were compared in both fasted and refed animals. During a 14-day fast both protein synthesis and respiration rates fell to stable values after 6 days. When a meal of whole sandeel at 6% body weight was fed to fish fasted for 6 days, protein synthesis and MO2 increased to a maximum at between 12 and 18 h after feeding. Peak MO2 was about twice the pre-feeding values, while whole animal protein synthesis increased four-fold. There were differences between tissues in the timing of maximum protein synthesis; the liver and stomach responded faster than the remainder of the body. Maximum protein synthesis rates in the liver and stomach occurred at 6 h after feeding, at which time their calculated contribution to total MO2 was 11%. Similar calculations suggested that the integrated increment in whole animal protein synthesis contributed between 23% and 44% of the post-prandial increase in MO2. It was concluded that protein synthesis is an important contributor to increased MO2 after feeding in cod.

Protein synthesis in a fish heart: responses to increased power output.

The effects of exercise on the rates of protein synthesis in the chambers of the trout heart were investigated in vitro and in vivo. An in vitro rainbow trout heart preparation was developed which permitted perfusion of the coronary supply to the compact region of the ventricular muscle. This preparation was used to examine the mechanical responses to preload pressures, the oxygen consumption at different power outputs and the rates of protein synthesis in the various heart components. By increasing preload pressure it was possible to double cardiac output, oxygen consumption and power output without changing heart rate. Mechanical efficiency of the hearts was approximately 20%. Perfusion of the coronary vessels improved cardiac output. Protein synthesis was measured in isolated hearts by the incorporation of [3H]phenylalanine added at high concentration (1.35 mmol l-1) to the perfusion medium. The various chambers of the heart showed marked differences in their rates of protein synthesis. Increasing cardiac output and power output in vitro by twofold over 20 min increased the fractional rate of protein synthesis by approximately 2.5-fold in the atrium and ventricle but did not affect the rates in the bulbus arteriosus. Perfusion of the coronary vessels significantly increased the rates of protein synthesis of the compact layer of the ventricle. In vivo there were no significant differences in the fractional protein synthesis rates between the atrium and ventricle; slow-speed continuous swimming over 40 min (1.5 body lengths s-1) caused an increase in the rates of protein synthesis in all the chambers except the bulbus arteriosus. The stimulation in the fractional rates of protein synthesis by approximately 32% was not as great as in vitro. Both in vivo and in vitro the increased rates of protein synthesis occurred without any change in RNA to protein ratios, indicating an improved activity of protein synthesis per unit of RNA. It is concluded that short-term increases in cardiac contractility, possibly acting through the mechanical stretch on the cardiac muscle, stimulated protein synthesis, particularly in the ventricle, through increased ribosomal activity.