Entity

Time filter

Source Type

New Brunswick, Canada

Braden L.M.,University of Victoria | Braden L.M.,College of the Atlantic | Barker D.E.,Vancouver Island University | Barker D.E.,Huntsman Marine Science Center | And 3 more authors.
Fish and Shellfish Immunology | Year: 2015

Juvenile pink salmon larger than 0.7 g reject the sea louse, Lepeophtheirus salmonis, and are considered resistant to the infection. Robust innate defense responses in the skin contribute to the observed resistance. In contrast adult pink salmon captured at sea or shortly before spawning carry large numbers of the parasite, suggesting inability to control the infection. The purpose of this research is to better understand these apparently contradictory conclusions by comparing a suite of genetic and cellular markers of resistance to L. salmonis in the skin of juvenile and mature pink salmon. The expression of major histocompatibility factor II, C-reactive protein, interleukin-1β, interleukin-8 and cyclooxygenase-2 was down-regulated in mature but not juvenile pink salmon. Similarly, skin at the site of parasite attachment in juvenile salmon was highly populated with MHIIβ+ and IL-1β+ cells that were either absent, or at reduced levels at similar sites in mature salmon. In addition, mucocyte density was relatively low in the skin of mature salmon, irrespective of louse infection. In juveniles, the higher mucocyte density decreased following louse attachment. We show that in mature pink salmon, genetic and histological responses in skin are depressed and speculate that salmonid defense against L. salmonis is modulated by maturation. © 2015. Source


Wildish D.J.,Canadian Department of Fisheries and Oceans | Wildish D.J.,Huntsman Marine Science Center
Journal of Natural History | Year: 2012

A lineal "island" theory is proposed to account for the dispersal of marine/estuarine, supralittoral talitrid populations, both to and from isolated shore "islands" on continental and true oceanic islands. Evolution may occur following dispersal to shores that are contiguous with ecologically open habitats, inclusive of sub-tropical forest litter and caves. Specific hypotheses of the lineal "island" theory are therefore: the conventional wrack hypothesis 1 - direct from marine supralittoral wrack to subtropical forest litter; the driftwood hypothesis 2(a) - direct from marine supralittoral driftwood to subtropical forest litter; the driftwood hypothesis 2(b) - direct from the marine supralittoral driftwood to caves opening on a marine supralittoral; and the driftwood hypothesis 2(c) - direct from the marine supralittoral driftwood via caves to subtropical forest litter. Circumstantial evidence supporting each hypothesis is presented using the ecology and distribution data of the talitrid fauna of the northeast Atlantic islands, north of 25°N and south of 40°N, including the Canaries, Madeira and the Azores archipelagos. The currently known talitrid fauna of all these islands includes 15 species: seven endemic, subtropical landhoppers, two synanthropically introduced landhoppers, three wrack generalists, one sand-burrowing specialist, one specialist cavehopper, and one specialist driftwood hopper. Based on distributional data from the northeastern Atantic islands, specialist driftwood hoppers have a long distance dispersal capability, which makes them potential colonizers of distant oceanic islands. Talitrids provide an excellent model of dispersal and speciation, whose evolutionary pathways can be solved by modern genetic methods. © 2012 Copyright Taylor and Francis Group, LLC. Source


Wildish D.J.,Canadian Department of Fisheries and Oceans | Wildish D.J.,Huntsman Marine Science Center | Martell D.J.,Canadian Department of Fisheries and Oceans
Zoosystematics and Evolution | Year: 2013

Describing and comparing epidermal integumentary pigment patterns is a relatively under-used method for taxonomically distinguishing many species of closely related amphipods (Crustacea, Amphipoda). Three general methods are available to do this: comparing photographs; creation of detailed drawings of one or more somites; and drawings of the pigment patterns of the whole dorsal body surface. We describe a simple digital method by which diagrams can be made of the dorsal pigment patterns (DPP) of the cephalon, peraeon, and pleon. Digital DPP diagrams are an inexpensive approach to the inclusion of epidermal pigment patterns as a means of identifying some, although not all, species of amphipods.© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Tosh J.J.,University of Guelph | Garber A.F.,Huntsman Marine Science Center | Garber A.F.,Canadian Department of Fisheries and Oceans | Trippel E.A.,Canadian Department of Fisheries and Oceans | Robinson J.A.B.,University of Guelph
Journal of Animal Science | Year: 2010

Variance components were estimated for 2 body size traits of Atlantic cod at 2 time points. Wild-caught founders from 3 regions off eastern North America were spawned and their progeny were reared at 2 locations in 2 consecutive years. Full-sib families (n = 148) were kept separate until individuals achieved a size large enough to be tagged. At that time (220 d of age), BW and length of 47,637 offspring from 90 sires and 89 dams were recorded. The juveniles were then transferred to sea cages at 3 sites, where they grew further for more than a year. A second set of measurements was collected on 11,839 fish (634 d of age). Dispersion parameters were estimated using REML in bivariate analyses. Models included fixed degree-days (covariate), year × location subclasses, and genetic groups composed of connected families within region of origin. Random factors were animal (additive genetic effects), considering known relationships among the fish; dam (maternal effects); and family (effects common to full-sibs). At tagging, heritability estimates were small to moderate (0.15 and 0.24 for BW and length, respectively; SE = 0.14), similar to or somewhat larger than the proportions of variation ascribed to dams and families (11 to 16%). Later, heritability estimates were greater (0.27 ± 0.08 and 0.31 ± 0.09 for BW and length, respectively), whereas dam and family variance proportions were very small (3 to 4%). Omitting maternal or family components substantially increased the values obtained for heritability at both time points. At the later point, failure to account for maternal effects inflated heritability estimates by about 24% for both traits; ignoring family effects had double the impact. These effects persisted even though endogenous feeding lasts only a couple of weeks in this species and the fish had been pooled since tagging. Discarding data from parents that were completely confounded with their mates decreased heritability estimates slightly (by 0.04, for both traits) at the second point, with no loss of precision despite 15% fewer records and 34% fewer parents; the improved design seemed to have more fully disentangled the additive genetic effects. Estimates of genetic correlations between traits and between time points were very large (>0.89). The results imply that genetic variation exists for body size of cod at both stages. Poor data structure and inadequate models can potentially lead to overstatement of heritability, and thus also of the predicted selection response. © 2010 American Society of Animal Science. Source


Gonzalez-Ortegon E.,Bangor University | Gonzalez-Ortegon E.,Spanish Institute of Oceanography | Sargent P.,Northwest Atlantic Fisheries Center | Pohle G.,Huntsman Marine Science Center | Martinez-Lage A.,University of La Coruna
Aquatic Invasions | Year: 2015

This study documents the introduction of the European Baltic prawn, Palaemon adspersus Rathke, 1837 to the coastal waters of northeastern North America, specifically the west coast of Newfoundland and the Magdalen Islands in the Gulf of St. Lawrence, Canada. Species identification was verified using morphological and genetic criteria. In September 2011, the first specimens of P. adspersus were collected in Gulf of St. Lawrence waters near Stephenville Crossing, Newfoundland, Canada. In 2012, additional P. adspersus specimens were collected in this area and at St. Andrew’s, located further south in western Newfoundland and in 2013 several egg-bearing females were collected further north in York Harbour. Accidental transport by ballast water of ships seems the likely vector for transport of Baltic prawn to the Gulf of St. Lawrence from Northern Europe or the Caspian Sea. It is possible that this shrimp has a wider presence in Atlantic Canadian waters but, due to its close resemblance to native shrimp species, it may have been previously misidentified, as occurred with specimens collected from the Magdalen Islands. We further expect that other species of the genus Palaemon, including P. elegans Rathke, 1837 from the Baltic Sea or northeastern United States, and P. macrodactylus Rathbun, 1902 from the northeastern United States, may invade the Gulf of St. Lawrence. We provide an illustrated key for the identification of these exotic Palaemon species and to differentiate them from native members of the subfamily Palaemoninae. © 2015 The Author(s). Source

Discover hidden collaborations