C. W. Bean

The Relationship Between Spatial Distribution and Diet of Arctic Charr, Salvelinus Alpinus, In Loch Ness, U.K.

The pelagic fish community of Loch Ness, U.K., is dominated by Arctic charr, Salvelinus alpinus. Previous studies have shown that the distribution of zooplankton along the south-west to north-east axis of this elongate loch is very dynamic and determined largely by prevailing winds, but Arctic charr are consistently more abundant in the southern half of the loch. In July 1993, the diet compositions of 161 Arctic charr from 53 to 330 mm in length were determined and related to their spatial distribution and those of microcrustacean zooplankton and pelagic chironomid larvae and pupae. Diets were dominated by chironomid larvae, with chironomid pupae, Bythotrephes longimanus, Bosmina coregoni and Daphnia hyalina also frequently taken. Over the whole study period, B. longimanus were more important in the diet of fish from the northern half of the loch, while chironomid larvae were more important for fish from the southern half. As a result, per capita prey weight of fish from the south was greater than that of fish from the north. However, wind-induced changes in the distribution of zooplankton along the loch were accompanied by a change in the diet composition of Arctic charr from the south.

Influences of the Tapeworm Ligula Intestinalis (L.) On the Spatial Distributions of Juvenile Roach Rutilus Rutilus (L.) and Gudgeon Gobio Gobio (L.) in Lough Neagh, Northern Ireland

The aims of the present study were to examine the influences of parasitization by Ligula intestinalis on the spatial distributions of juvenile roach and gudgeon in Lough Neagh, a large eutrophic lake in Northern Ireland. Infestation by Ligula was found to have no effect on the autumnal offshore migration of smaller gudgeon (median length 60 mm, mainly 1+ in age) and roach (median length 56 mm, mainly 1+ in age), although it was previously found to affect the migration of larger, older gudgeon (median length 90 mm, mainly 2+ in age) (the offshore migration of larger roach was not studied). Infestation also had no effect on the summer vertical distributions of smaller gudgeon and roach, but there was a significant effect on larger gudgeon and roach (median length 83 mm, mainly 2+ in age). Within the size ranges studied, larger fish of each species harboured larger parasites, but the precise relationship between host size and parasite size differed significantly. The effect, or otherwise, of Ligula on roach and gudgeon distributions is not related solely to the relative weights of the parasite and host.

Sneak male mating tactics between lampreys (Petromyzontiformes) exhibiting alternative life-history strategies

Interspecific sneak male mating tactics between paired lamprey species are described for the first time. Although alternative mating tactics among petromyzontids have been described previously, including intraspecific sneak males, the presence of sneak male tactics between parasitic and non-parasitic forms suggests that high levels of gene flow between putative lamprey species could remain high, despite large body size discrepancies.

Conservation of the vendace (Coregonus albula), the U.K.'s rarest freshwater fish

Although also formerly present in two lochs in South West Scotland, populations of vendace (Coregonus albula) were until recently believed to persist in only two U.K. lakes, i.e., Bassenthwaite Lake and Derwent Water in North West England. However, although Derwent Water has retained its natural mesotrophic conditions and the status of its vendace population is acceptable, monitoring at Bassenthwaite Lake has failed to record any specimens since 2000 and the species has recently been declared locally extinct. Bassenthwaite Lake has experienced increasing problems from eutrophication, sedimentation and the introduction of fi sh species including roach (Rutilus rutilus) and ruffe (Gymnocephalus cernuus), both of which have more recently also been introduced to Derwent Water and give concern over possible food competition and egg predation. In addition to monitoring, considerable efforts have been made in recent years to conserve vendace through the protection and improvement of their habitats and the establishment of refuge populations. The latter has resulted in the establishment of a population originating from Bassenthwaite Lake in Loch Skeen of South West Scotland, with further attempts still in progress at two other sites. Public awareness of the conservation of this species, which is the U.K.s rarest freshwater fish, has also been actively promoted.

Are phenotypic traits useful for differentiating among a priori Coregonus taxa

A key for three putative species apparently found in three geographic areas, i.e. Coregonus clupeoides (in Scotland), Coregonus stigmaticus (in England), and Coregonus pennantii (in Wales) given in a recent review was tested quantitatively using 544 individuals from nine populations. The classification success of the key was very low (27%). It was concluded that there is currently no robust evidence for the recognition of the three putative species. Furthermore, the use of phenotypic characters alone to distinguish putative species in postglacial fish species such as those of the genus Coregonus that show homoplasy in many of these traits is questioned. In the absence of further evidence, it was concluded that a single highly variable species best describes the pattern of phenotypic variation in these U.K. populations. On this basis it is argued that taxonomic subdivision of U.K. European coregonids is inappropriate and that Coregonus lavaretus should prevail as the species name applicable to all populations.

Inter and intra-population phenotypic and genotypic structuring in the European whitefish Coregonus lavaretus, a rare freshwater fish in Scotland

This study revealed between-lake genetic structuring between Coregonus lavaretus collected from the only two native populations of this species in Scotland, U.K. (Lochs Eck and Lomond) evidenced by the existence of private alleles (12 in Lomond and four in Eck) and significant genetic differentiation (FST = 0·056) across 10 microsatellite markers. Juvenile C. lavaretus originating from eggs collected from the two lakes and reared in a common-garden experiment showed clear phenotypic differences in trophic morphology (i.e. head and body shape) between these populations indicating that these characteristics were, at least partly, inherited. Microsatellite analysis of adults collected from different geographic regions within Loch Lomond revealed detectable and statistically significant but relatively weak genetic structuring (FST = 0·001-0·024) and evidence of private alleles related to the basin structure of the lake. Within-lake genetic divergence patterns suggest three possibilities for this observed pattern: (1) differential selection pressures causing divergence into separate gene pools, (2) a collapse of two formerly divergent gene pools and (3) a stable state maintained by balancing selection forces resulting from spatial variation in selection and lake heterogeneity. Small estimates of effective population sizes for the populations in both lakes suggest that the capacity of both populations to adapt to future environmental change may be limited.

Assessment and conservation of whitefish (Coregonus lavaretus) in the U.K.

The whitefish (Coregonus lavaretus (L.)) is of high biodiversity value in the U.K., where it exists as a total of only seven native populations in England (Brotherswater, Haweswater, Red Tarn and Ullswater), Scotland (Loch Eck and Loch Lomond) and Wales (Llyn Tegid also known as Bala Lake), and is protected by national conservation legislation. However, an absence of fisheries means that information on its populations is scarce and must be obtained by dedicated surveys and associated activities. A standardised national assessment protocol using hydroacoustics and survey gill netting is described and results are presented from its use on the three whitefish populations of Scotland and Wales. For the remaining four English populations where the assessment protocol has not yet been specifically applied, comparable data are available from similar surveys, augmented by long-term fish entrapment records at one lake. These surveys revealed that the whitefish populations of Loch Eck, Red Tarn and Ullswater were in favourable condition. However, the condition of whitefish in Brotherswater, Haweswater, Llyn Tegid and Loch Lomond was considered to be unfavourable. Conservation measures specific to the whitefish populations of greatest concern in Haweswater, Llyn Tegid and Loch Lomond are described, including the management of water levels, local control of nesting cormorants (Phalacrocorax carbo (L.)) and establishment of refuge populations.

Conservation Evo-Devo: Preserving Biodiversity by Understanding Its Origins

Unprecedented rates of species extinction increase the urgency for effective conservation biology management practices. Thus, any improvements in practice are vital and we suggest that conservation can be enhanced through recent advances in evolutionary biology, specifically advances put forward by evolutionary developmental biology (i.e., evo-devo). There are strong overlapping conceptual links between conservation and evo-devo whereby both fields focus on evolutionary potential. In particular, benefits to conservation can be derived from some of the main areas of evo-devo research, namely phenotypic plasticity, modularity and integration, and mechanistic investigations of the precise developmental and genetic processes that determine phenotypes. Using examples we outline how evo-devo can expand into conservation biology, an opportunity which holds great promise for advancing both fields.

Evidence of a recent decline in river lamprey Lampetra fluviatilis parasitism of a nationally rare whitefish Coregonus lavaretus: is there a diamond in the ruffe Gymnocephalus cernuus?

Lamprey-induced scarring of the nationally rare Coregonus lavaretus, a known host of a freshwater-resident population of European river lamprey Lampetra fluviatilis, was found to have declined precipitously since the establishment of several non-native fishes in Loch Lomond. Evidence presented in this study points to the possibility that L. fluviatilis in this lake may have altered its trophic ecology in response to the negative impact that non-native species, in particular ruffe Gymnocephalus cernuus, have had on their favoured host.

The Scottish invasion of pink salmon in 2017

Pink salmon Oncorhynchus gorbuscha (Walbaum 1792) (reviewed by Heard, 1991 and Quinn, 2006) is the smallest of the migratory Pacific salmon. As natives of the Pacific Ocean, they spawn in fresh water at latitudes between about 40o and 70o N in countries bordering both sides of the Pacific Ocean. This article is protected by copyright. All rights reserved.