Arctic Lamprey Lethenteron Camtschaticum Research Articles

No strict host specificity: Brain metacercariae Diplostomum petromyzifluviatilis Müller (Diesing, 1850) are conspecific with Diplostomum sp. Lineage 4 of Blasco-Costa et al. (2014).

Metacercariae of Diplostomum petromyzifluviatilis (Digenea, Diplostomidae) from the brain of European river lamprey Lampetra fluviatilis from the Baltic Sea basin and Arctic lamprey Lethenteron camtschaticum from the White Sea basin were studied with the use of genetic and morphological methods. Phylogenetic analysis based on cox1 marker showed that the parasites of both lamprey species were conspecific with Diplostomum sp. Lineage 4 of Blasco-Costa et al. (2014). The name Diplostomum petromyzifluviatilis Müller (Diesing, 1850) has historical precedence as a species described from the brain of lampreys and should be used in genus nomenclature. There were no morphological qualitative differences between the metacercariae from the two lamprey species but those from L. fluviatilis were larger than those from L. camtschaticum. We expanded the data on the second intermediate hosts and the localization of D. petromyzifluviatilis, showing that its metacercariae occur not only in the brain of lampreys but also in the brain and the retina of three-spined stickleback Gasterosteus aculeatus and the vitreous humour of the perch Perca fluviatilis across the European part of the Palearctic.

Historical distribution of Arctic lamprey Lethenteron camtschaticum in Japanese rivers and its change estimated from fishery statistics and fishers’ local ecological knowledge

This study identified the location and geographical characteristics of rivers where Arctic lamprey Lethenteron camtschaticum were captured in the past and present in Japan and evaluated the effectiveness of the local ecological knowledge (LEK) held by inland fishers for estimating species distribution. We collected information about fishery harvests for Arctic lamprey from fishery statistics published in the 1930s and directly from inland fishery cooperatives (FCs). The presence of a historical harvest and its southern limit were largely consistent between the two resources. The fishery harvest was historically distributed in relatively large rivers, with a low downstream gradient, along the Sea of Japan, and the southern limit was estimated to be in the range of 36.45–37.33° N. The number of active FCs decreased from a historical value of 59 to only 14 at present. The southern limit shifted further north to 43.13° N. The LEK from FCs provided sufficient information to estimate the spatial distribution within the local rivers and revealed that a decline in fishery activity had occurred in the upper reaches of rivers. Our data can be used as a baseline for the restoration of Arctic lamprey and to develop a monitoring tool to improve the conservation of inland biodiversity.

New Data on the Distribution of Lamprey Petromyzon marinus and Lethenteron camtschaticum (Petromyzontidae) in Barents and White Seas

Information about the sites of catches of the sea lamprey Petromyzon marinus in the western Barents Sea and Arctic lamprey Lethenteron camtschaticum in the Barents and White seas is presented based on the data of trawl surveys performed in 2004−2016. It is demonstrated that sea lamprey is occasionally encountered in the western Barents Sea; nine specimens have been recorded during the entire period of surveys. The northernmost point of a capture of sea lamprey is located near 76° N and the easternmost point is at 31°15′ E. Arctic lamprey is not numerous in the Barents and White seas; a total of 66 and 17 specimens have been caught, respectively. Its local aggregations are found in the southeastern part of the Barents Sea and in Dvina Bay in the White Sea. Arctic lamprey penetrates to the north to 76° N and into the central part of the Barents Sea.

Spatial Differences in the Distributions of Arctic and Pacific Lampreys in the Eastern Bering Sea

AbstractThe Arctic Lamprey Lethenteron camtschaticum and Pacific Lamprey Entosphenus tridentatus are ecologically and culturally valuable native species that co‐occur in the eastern Bering Sea. Lamprey wounds are often observed on fishes in this region, yet there is a paucity of information on the distribution of anadromous lampreys, lamprey–host interactions, and foraging behavior in the ocean. Our hypothesis was that each lamprey species would be positively associated (distribution and abundance) with their presumed hosts: Arctic Lampreys with smaller fishes that could easily be killed, and Pacific Lampreys with larger hosts that could sustain blood feeding. To examine lamprey distribution, abundance, and associations, we utilized data from two fishery‐independent surveys—one epipelagic trawl survey and one benthic trawl survey—conducted between 2002 and 2012 in the eastern Bering Sea. Distinct distributions of lamprey species were evident in models of their presence and absence by latitude and longitude. Arctic Lampreys inhabited the northern regions on the inner/middle continental shelf in depths less than 100 m, while Pacific Lampreys inhabited waters deeper than 150 m along the continental slope. Pacific Herring Clupea pallasii and juvenile salmonids were found in regions with relatively high Arctic Lamprey catches in the epipelagic trawl survey, and catches of lampreys and these potential hosts were positively correlated. Demersal groundfishes were found in regions with relatively high Pacific Lamprey abundance in the benthic trawl survey, but catches of Pacific Lampreys and these hosts were not consistent. We conclude that Arctic Lampreys and Pacific Lampreys are segregated in the eastern Bering Sea, and although differences in their distributions may be explained by species‐specific host preferences, alternate explanations include differences in seasonal movements, source river locations, and marine residence times. This study provides an initial baseline of the oceanic ecology of lampreys, which increases our understanding of species‐specific differences beyond traditional freshwater studies.

Distribution and ecology of lampreys Lethenteron spp. in interior Alaskan rivers.

This study describes phenetic characteristics and examines the life history of anadromous Arctic lamprey Lethenteron camtschaticum and freshwater-resident Alaskan brook lamprey Lethenteron alaskense in two tributaries of the middle Yukon River, Alaska. Larval lampreys could not be identified to species using pigmentation density patterns or trunk myomere counts, but adults could be identified to species based on colouration, body size and oral-disc dentition. Although larvae were patchily distributed in both rivers, there was a greater proportion of sample locations where Lethenteron spp. were absent in upper reaches than in middle and lower reaches. Relative abundance, density and median and maximum total length (LT ) of larvae were highly variable among sampling locations. Current velocity, substratum type and coarse woody debris were most strongly correlated with larval Lethenteron spp. density; velocity and substratum size was negatively correlated, whereas woody debris was positively correlated. Water depth, dissolved oxygen levels and specific conductance did not influence habitat selection. Length-frequency distributions, diet composition (organic detritus ≥ 98%), assimilation efficiency (>70%) and gut fullness (<0·2 mg diet ash-free dry mass) were similar for larvae, regardless of river or sampling location. These results increase understanding of Lethenteron spp. biology and ecology in interior Alaska drainages and add to the existing literature on Lethenteron spp. life history.

Interpreting Lamprey Attacks on Pacific Cod in the Eastern Bering Sea

AbstractAdult anadromous lampreys attack several species targeted by large‐scale commercial fisheries in the North Pacific Ocean, and the potential negative impact to these host fishes is not well understood. The Arctic Lamprey Lethenteron camtschaticum and Pacific Lamprey Entosphenus tridentatus are anadromous species that feed in the eastern Bering Sea, and lamprey parasitism is evident on Pacific Cod Gadus macrocephalus near the Bering Slope. To examine this parasitic interaction, we first built models using morphological measurements from lamprey oral discs to predict which lamprey species caused the observed wounds on Pacific Cod. We then examined lamprey wounding rates and explored healing patterns related to the severity and location of lamprey wounds. We scanned 8,746 Pacific Cod for lamprey wounds and found that 4.9% of the cod had at least one wound. Lamprey wound morphology was better predicted by an oral disk model built for Pacific Lamprey than by a similar model built for Arctic Lamprey. The occurrence of lamprey wounds that had penetrated muscle tissue but had not completely healed was more prevalent as Pacific Cod length increased. Generalized additive model results indicated that latitude and mean Pacific Cod length were important in predicting lamprey wounding rates at a sampling station. Recently inflicted lamprey wounds that penetrated Pacific Cod muscle tissue were observed four times as often as superficial wounds that did not penetrate muscle tissue, but superficial wounds were twice as likely to reach a completely healed state. No difference was detected in the likelihood of a lamprey wound to reach a completely healed state among different host body regions. While there is a potential for lamprey attacks to negatively affect individual host fish, we emphasize the importance of understanding population dynamics between native lampreys and their hosts, as this could aid in explaining variations in the natural mortality of commercially important fish species in the eastern Bering Sea.

Distribution and size composition of the arctic lamprey Lethenteron camtschaticum in the North Pacific

Results of the long-term study of the spatial and vertical distribution of the parasitic anadromous Arctic lamprey Lethenteron camtschaticum (Tilesius, 1811) (Petromyzontidae) in the North Pacific and data on its size composition are given. This species is most frequent in the northwestern Sea of Japan and the western Bering Sea. The maximum concentrations are noted in waters of southern Primorye, southwestern Sakhalin, the northwestern part of the Sea of Okhotsk, and the northern part of the Bering Sea, which is probably explained by the increased number of its victims, Pacific salmon. Near the bottom, Pacific lampreys are extremely few and are primarily encountered at depths less that 400 m, and in the Pelagic zone, in the 100-m layer. The catches have contained Arctic lampreys having a total length of 15–79 cm. The lampreys of several size groups in the catches may indicate that L. camtschaticum spends not less than four years in the sea. No relationship has been found between the body length and the capture depth. Analyzed are the relationships between the body length and weight and the body length and the condition factor. The seasonal dynamics of these indices are considered.

Review on parasitic and non-parasitic forms of the arctic lamprey Lethenteron camtschaticum (Petromyzontiformes, Petromyzontidae) in the Eurasian arctic

Arctic lamprey Lethenteron camtschaticum is an important and poorly studied component of the aquatic ecosystems in the Northern part of Eurasia. In this region, the species has two life history forms: anadromous and resident, which are very closely related genetically. In this review data on morphology, distribution, ecology, abundance, economic value and preservation of these two forms from the basins of the Barents, White, Kara, Laptev, East Siberian, Chukchi and Bering Seas are presented (over 70 rivers in 9 Russian watershed districts). For the first time, rigorous amounts of previously published and authors’ own experimental data, observations and Russian historical documents, normally unobtainable for English speaking researchers, have been comprehensively analyzed. The review leads to the understanding of the forms belonging to the same species.

Population structure and gene flow among anadromous arctic lamprey (Lethenteron camtschaticum) populations deduced from polymorphic microsatellite loci

Information on migration ecology is important for effective conservation and management of fishery resources, particularly diadromous animals. We investigated the genetic population structure and gene flow pattern of anadromous Arctic lamprey Lethenteron camtschaticum by analyzing polymorphic microsatellite loci. Bayesian population structure analysis was used to estimate the existence of two genetically divergent ancestral sources and latitudinal gradual changes of their frequencies among the present populations. When hypotheses of historical migration models were tested using coalescent-based methods, the best model was found to be an n-island model assuming equal population size and reciprocal migration among all populations. These results suggest that L. camtschaticum has considerable ability to migrate long distances in the sea and has lower homing abilities. For resource management of L. camtschaticum, unconstrained gene flow across all populations should be maintained. The present findings might be beneficial for conservation and contribute the sustainable use of L. camtschaticum resource.

Downstream migration in ammocoetes of the Arctic lamprey Lethenteron camtschaticum in some Kamchatka rivers

This paper considers the major patterns of downstream migration in Arctic lamprey ammocoetes in Kamchatka rivers. Ammocoetes of different age groups are shown to be constantly noted in the composition of the migrant part of a river community. The greatest intensity of downstream migration in ammocoetes of the age class 0+ is noted in the period of their primary dispersion in late July-early August. The ammocoetes of the age groups 1+ and older migrate from spring to late autumn, but their concentrations are not high. The significant similarity of such a biologic feature as downstream migration in ammocoetes and juvenile salmonids serves as an example of ecological analogy.

Population structure of arctic lamprey Lethenteron camtschaticum from the Kol River (Western Kamchatka)

Phenetic diversity is investigated and the taxonomic status of lampreys (Petromyzontidae) from the Kol basin (Western Kamchatka) is verified. Typically anadromous lamprey, anadromous lamprey forma praecox, resident lamprey, smolts, and larvae of lamprey are discovered and described. Their comparative analysis is made by standard morphometric characters. Differences between the forms by plastic characters depend on size and weight. No significant differences are found by major taxonomic characters between the forms of anadromous and resident lampreys which would indicate their taxonomic separation. Phenetic types of spawners are representatives of the population of one complexly structured species represented by life forms realizing different life history strategies (anadromous and resident), and belong to the species Arctic lamprey Lethenteron camtschaticum (Tilesius, 1811).

Sexual dimorphism and some special traits of spawning behavior of the Arctic Lamprey Lethenteron camtschaticum

The sexual dimorphism and the role of secondary sexual characters in the spawning period of the Arctic Lamprey Lethenteron camtschaticum from the Utkholok basin (Kamchatka) are studied for the first time. The importance of the urogenital papilla in males and of the keel in females during egg fertilization and in con- struction of the redd is shown. By visual observations, underwater and above water videography, two forms of spawning behavior are revealed: group behavior in the current and paired behavior in the inshore part of the river, where the current is slower. The typically anadromous form, the anadromous forma praecox, and river lamprey reproduce together. The strategy of the spawning behavior is directed first of all towards better fertili- zation of eggs and finally towards reproductive success of the species.