Two New Host Species for the Parasitic Fungus Ichthyophonus hoferi in the Northwest Atlantic

1972 ◽  
Vol 29 (12) ◽  
pp. 1776-1777 ◽  
Author(s):  
Jerry D. Hendricks
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Parasitic Fungus ◽  
New Host ◽  
Yellowtail Flounder ◽  
Limanda Ferruginea ◽  
New Hosts ◽  
Longhorn Sculpin ◽  
New Host Species

Microscopic examination of kidney tissues from eight Gulf of Maine fish species revealed cysts of the fungus Ichthyophonus hoferi, Plehn and Mulsow, in individuals from three species. Two of these species, the longhorn sculpin (Myoxocephalus octodecemspinosus) and the Atlantic cod (Gadus morhua), are new hosts for this parasite in Gulf of Maine waters. The other species, the yellowtail flounder (Limanda ferruginea), was previously reported as an Ichthyophonus host.

Corynosoma wegeneri (Acanthocephala: Polymorphida) and Pseudoterranova decipiens (Nematoda: Ascaridoidea) Larvae in Scotian Shelf Groundfish

1992 ◽  
Vol 49 (10) ◽  
pp. 2062-2069 ◽  
Author(s):  
David J. Marcogliese ◽  
Gary McClelland
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Host Record ◽  
Melanogrammus Aeglefinus ◽  
Scotian Shelf ◽  
New Host ◽  
New Host Record ◽  
Pseudoterranova Decipiens ◽  
Sea Raven ◽  
Longhorn Sculpin

We examined larvae of the seal parasites Corynosoma wegeneri and Pseudoterranova decipiens in various fish species collected from Western and Sable Island banks between February 1989 and October 1990. Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice (Hippoglossoides platessoides), yellowtail flounder (Pleuronectes ferrugineus), windowpane (Scophthalmus aquosus), longhorn sculpin (Myoxocephalus octodecemspinosus), and sea raven (Hemitripterus americanus) were infected by both parasites, longhorn sculpin being a new host record for C. wegeneri. Only C. wegeneri occurred in winter flounder (Pleuronectes americanus), and neither parasite was found in northern sand lance (Ammodytes dubius) or capelin (Mallotus villosus). The two parasites were most numerous in sea raven and longhorn sculpin. Corynosoma wegeneri was more prevalent in fish sampled in 1989–90 than in previous surveys of Atlantic cod and haddock from the Scotian Shelf. Pseudoterranova decipiens and C. wegeneri occurred throughout the sampling area, but small fishes in the vicinity of Sable Island had the heaviest sealworm infections, and both parasites in longhorn sculpin declined with distance from Sable Island. Increases of C. wegeneri in groundfish, like recent increased levels of P. decipiens infection on the Scotian Shelf, can be attributed to the dramatic growth of the grey seal (Halichoerus grypus) population on Sable Island.

scholarly journals Surveys of larval sealworm (Pseudoterranova decipiens) infection in various fish species sampled from Nova Scotian waters between 1988 and 1996, with an assessment of examination procedures

2001 ◽  
Vol 3 ◽  
pp. 57 ◽  
Author(s):  
G McClelland ◽  
DJ Martell
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
New Host ◽  
Pseudoterranova Decipiens ◽  
Infection Parameters ◽  
Routine Inspection ◽  
Frozen Fish ◽  
Nova Scotian ◽  
New Host Records ◽  
Benthic Consumers

Between November 1988 and October 1996, >10,000 fish from the Breton Shelf, Sable Island Bank and the northeastern Gulf of Maine were examined for larval anisakines. Larval sealworm, Pseudoterranova decipiens, occurred in 30 of 39 species surveyed, including 8 new host records, Enchelyopus cimbrius, Lycodes reticulatus, Eumesogrammus praecisus, Lumpenus lumpretaeformis, Lumpenus maculatus, Cryptacanthodes maculatus, Artediellus atlanticus and Triglops murrayi. The parasite was most prevalent and abundant in mature demersal piscivores and benthic consumers. Sealworm densities (nr kg-1 host wt.), however, were greatest in small benthophagous fish including mature E. cimbrius, A. atlanticus, T. murrayi and Aspidophoroides monopterygius, and juvenile Hippoglossoides platessoides. ANOVA revealed that geographical disparities in sealworm prevalence and abundance were highly significant in 14 of 20 species tested, although significant disparities between samples from each of the three areas were evident only in H. platessoides. Almost invariably, infection parameters were greatest in fish from Sable Island Bank. ANOVA also indicated that sealworm prevalence and/or abundance increased significantly in Sable Island Bank populations of Gadus morhua, H. platessoides, and seven other species between 1985-1986 and 1989-1990. Routine examinations, in which host flesh was sliced and candled, proved as efficacious as digestion in warm (35° C) pepsin-HCl for detection of larval sealworm in the flesh of large frozen fish. Procedures employing fresh (iced) samples, digestion at ambient temperature and microscopy are recommended, however, for surveys of small benthic consumers. Many of the sealworm infecting the latter hosts are tiny (2 to 10 mm in length) nematodes, which escape detection by routine inspection, and may not survive in warm pepsin-HCl solution.

Oxidative stress, DNA damage and p53 expression in the larvae of atlantic cod (Gadus morhua) exposed to ultraviolet (290–400 nm) radiation

2001 ◽  
Vol 204 (1) ◽  
pp. 157-164 ◽  
Author(s):  
M.P. Lesser ◽  
J.H. Farrell ◽  
C.W. Walker
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Growth Arrest ◽  
Individual Performance ◽  
Cellular Growth ◽  
Pyrimidine Dimer ◽  
Uvb Radiation

Decreases in stratospheric ozone levels from anthropogenic inputs of chlorinated fluorocarbons have resulted in an increased amount of harmful ultraviolet-B (UVB, 290–320 nm) radiation reaching the sea surface in temperate latitudes (30–50 degrees N). In the Gulf of Maine, present-day irradiances of ultraviolet-A (UVA, 320–400 nm) radiation can penetrate to depths of 23 m and UVB radiation can penetrate to depths of 7–12 m, where the rapidly developing embryos and larvae of the Atlantic cod (Gadus morhua) are known to occur. Laboratory exposures of embryos and larvae of Atlantic cod to ultraviolet radiation (UVR) equivalent to a depth of approximately 10 m in the Gulf of Maine resulted in significant mortality of developing embryos and a decrease in standard length at hatching for yolk-sac larvae. Larvae at the end of the experimental period also had lower concentrations of UVR-absorbing compounds and exhibited significantly greater damage to their DNA, measured as cyclobutane pyrimidine dimer formation, after exposure to UVB radiation. Larvae exposed to UVB radiation also exhibited significantly higher activities and protein concentrations of the antioxidant enzyme superoxide dismutase and significantly higher concentrations of the transcriptional activator p53. p53 is expressed in response to DNA damage and can result in cellular growth arrest in the G1- to S-phase of the cell cycle or to programmed cell death (apoptosis). Cellular death caused by apoptosis is the most likely cause of mortality in embryos and larvae in these laboratory experiments, while the smaller size at hatching in those larvae that survived is caused by permanent cellular growth arrest in response to DNA damage. In addition, the sub-lethal energetic costs of repairing DNA damage or responding to oxidative stress may also contribute to poor individual performance in surviving larvae that could also lead to increases in mortality. The irradiances of UVB radiation that elicit these responses in cod larvae can occur in many temperate latitudes, where these ecologically and commercially important fish are known to spawn, and may contribute to the high mortality of cod embryos and larvae in their natural environment.

The influence of spatially variable and connected recruitment on complex stock dynamics and its ecological and management implications

2019 ◽  
Vol 76 (6) ◽  
pp. 937-949 ◽  
Author(s):  
Lisha Guan ◽  
Yong Chen ◽  
James A. Wilson ◽  
Timothy Waring ◽  
Lisa A. Kerr ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Temporal Trends ◽  
Substantial Reduction ◽  
Management Implications ◽  
Agent Based ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The Individual

To evaluate the influence of spatially variable and connected recruitments at spawning component scale on complex stock dynamics, a typical agent-based complex stock was modeled based on the Atlantic cod (Gadus morhua) stock in the Gulf of Maine. We simulated three scenarios with different degrees of connectivity (i.e., individual exchange) between the spatially variable recruitments of 36 spawning components within four subpopulations under the stock. Subsequently, the temporal trends were compared for different scenarios in age-1 recruitment, spawning stock biomass, and local depletion proportion of the overall complex stock and the individual subpopulations. Results show that increased recruitment connectivity from 0.1–0.2 to 0.6–0.8 between various components tends to increase the productivity and stability of a complex stock at local and global scales and reduce the proportion of depleted components due to overfishing. Moreover, depletions of less productive components may occur without a substantial reduction in the overall complex stock biomass and recruitment.

Host species of mistletoes (Loranthaceae and Viscaceae) in Australia

2020 ◽  
Vol 68 (1) ◽  
pp. 1
Author(s):  
Nicole F. Clark ◽  
Jen A. McComb ◽  
Andrew W. Taylor-Robinson
Keyword(s):  
Alien Species ◽  
Host Species ◽  
Current Knowledge ◽  
Sampling Effort ◽  
New Host ◽  
Host Family ◽  
Single Host ◽  
New Hosts ◽  
Host Families ◽  
New Host Species

In order to study the relationships between mistletoes and their host species, comprehensive collections of both mistletoes and hosts are needed. The effect of sampling effort on the estimation of mistletoe host range was demonstrated in a comparison of an inventory of host mistletoe interactions published by Downey in 1998 and a 2019 inventory presented here, which is based on data from collections in the Australian Virtual Herbarium and information in the literature. New hosts were recorded for 93% of the 90 Australian mistletoes. There were 338 previously known hosts recorded to be parasitised by additional mistletoe species, and 317 new host species that were not previously known as mistletoe hosts (25 being alien species). These were from 78 new host genera and 13 new host families. The total number of host species was 1186 within 327 genera from 92 host families. A total of 63% of all Australian mistletoes parasitise species of either Eucalyptus or Acacia or both these genera. The large rise in host species recorded in less than two decades between inventories suggests that current knowledge of hosts is still incomplete, such that further new hosts will be discovered in future. Some mistletoe species show a strong preference to one host family or genus but due to insufficient collecting it is premature to conclude that any of the three species known from a single host are host specific.

The influence of forage fish abundance on the aggregation of Gulf of Maine Atlantic cod (Gadus morhua) and their catchability in the fishery

2014 ◽  
Vol 71 (9) ◽  
pp. 1349-1362 ◽  
Author(s):  
David E. Richardson ◽  
Michael C. Palmer ◽  
Brian E. Smith
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Distribution Patterns ◽  
Fish Populations ◽  
Dependent Data ◽  
Forage Fish ◽  
Catch Per Unit Effort ◽  
Sand Lance ◽  
Unit Effort

Shifts in the distribution and aggregation patterns of exploited fish populations can affect the behavior and success of fishermen and can complicate the interpretation of fisheries-dependent data. Starting in 2006, coinciding with an increase in sand lance (Ammodytes spp.) abundance, Gulf of Maine Atlantic cod (Gadus morhua) concentrated on Stellwagen Bank, a small (405 km2) underwater plateau located in the southwestern portion of the larger (52 461 km2) stock area. The cod fishery in turn concentrated on Stellwagen Bank. Specifically, the proportion of Gulf of Maine cod landings caught in a single 10-minute square area (260 km2) encompassing the tip of Stellwagen Bank increased from 12% in 2005 to 45% in 2010. An increase in landings per unit effort in the fishery coincided with the concentration of the fleet on Stellwagen Bank. Overall, both fisheries-independent and fisheries-dependent data indicate that an increase in sand lance abundance resulted in cod aggregating in a small and predictable area where they were easily caught by the fishery. More broadly, this work illustrates how changes in the distribution patterns of fish and fisherman can decouple trends in abundance and fisheries catch per unit effort.

scholarly journals Estimating and mitigating the discard mortality of Atlantic cod (Gadus morhua) in the Gulf of Maine recreational rod-and-reel fishery

2016 ◽  
Vol 73 (9) ◽  
pp. 2342-2355 ◽  
Author(s):  
Connor W. Capizzano ◽  
John W. Mandelman ◽  
William S. Hoffman ◽  
Micah J. Dean ◽  
Douglas R. Zemeckis ◽  
...  
Keyword(s):  
Best Practice ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Related Factors ◽  
Discard Mortality ◽  
Recreational Fishery ◽  
Receiver Array ◽  
Management Plans

Abstract In recent years, the recreational contribution to the total catch of Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) has increased with recreational discards outnumbering recreational landings by 2:1. However, the discard mortality (DM) rate of cod released in the recreational fishery remains poorly understood, thus contributing to the uncertainty in stock assessments and fishery management plans. The current study examined the capture-related factors most detrimental to cod DM in the GOM recreational rod-and-reel fishery. Atlantic cod (n = 640; 26.0–72.0 cm) were angled from June–October 2013 on southern Jeffreys Ledge in the western GOM using fishing gear representative of the local recreational fishery. A subset (n = 136) was also tagged with pressure-sensing acoustic transmitters before being released into an acoustic receiver array (n = 31) deployed to monitor survival up to 94 days. To properly model DM up to the fishery-wide level, all cod were visually assessed for capture-related injuries according to a four-level injury score index. Mean tackle-specific DM rates of 15.4 and 21.2% were estimated for bait- and jig-captured cod, respectively, with an overall 16.5% mean DM rate for the 2013 GOM recreational cod fishery. Twenty-nine cod tagged with acoustic transmitters were identified as dead, where the majority (∼90%) died within 16 h post-capture. Upon evaluation with a specifically adapted parametric survival analysis, greater incidence of mortality was attributed to the capture and handling process (rather than release) for moderately and severely injured cod. Based on the capture-related factors associated with the highest injury rates, we recommend minimizing fight and handling times, avoiding areas with small cod, educating inexperienced anglers, and favouring bait over jigs to mitigate mortality. Results will continue to inform the development of fishery management plans and enhance survival through dissemination of “best practice” techniques to fishery stakeholders.

Advances in Fish Tagging and Marking Technology

2012 ◽  
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Stock Assessment ◽  
Stock Identification ◽  
Quality Of Data ◽  
Mark Recapture ◽  
International Industry ◽  
Research Initiatives

<i>Abstract</i>.—In the Gulf of Maine region, Atlantic cod <i>Gadus morhua</i>, are managed as three separate stocks: in U.S. waters, the Gulf of Maine (5Y) and Georges Bank (5Z) stocks and in Canadian waters, the Bay of Fundy stock (4X). The Northeast Regional Cod Tagging Program (NRCTP), a large-scale, international collaborative tagging program, was initiated in 2003 and provides the first region-wide, international snapshot of cod movements, mixing, and growth across all three management areas. As the 2008 stock assessment of Atlantic cod was approaching, these mark–recapture data (114,473 tag releases and >6,500 recaptures) were being analyzed for stock identification purposes. Analysis of raw and weighted data indicate exchanges between different areas which are likely related to spawning behavior, maturation, and environmental conditions. Two core assumptions when defining a stock are that (1) the stock is self-sustaining and that (2) neighboring stocks exist in isolation; the migration patterns observed in the current study may substantially violate both assumptions. With additional ongoing assessments into spatial variation in key life history characteristics of growth and natural mortality, the NRCTP exemplifies the role of conventional mark–recapture data in the complex process of stock identification. The geographic scale and quality of data collected during the NRCTP also confirm the value of international, industry-science collaborative research initiatives; involving this data in both stock assessments and future management initiatives is rewarding to the ~250 commercial and recreational fishermen who tagged cod for this program.

Using acoustic telemetry to observe the effects of a groundfish predator (Atlantic cod, Gadus morhua) on movement of the American lobster (Homarus americanus)

2013 ◽  
Vol 70 (11) ◽  
pp. 1625-1634 ◽  
Author(s):  
Marissa D. McMahan ◽  
Damian C. Brady ◽  
Diane F. Cowan ◽  
Jonathan H. Grabowski ◽  
Graham D. Sherwood
Keyword(s):  
Home Range ◽  
Behavioral Response ◽  
Acoustic Telemetry ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Homarus Americanus ◽  
American Lobster ◽  
Habitat Area ◽  
Predation Rates

American lobster (Homarus americanus) landings have more than quadrupled in the last two decades (1990–2010), coinciding with the collapse of Gulf of Maine groundfish fisheries such as Atlantic cod (Gadus morhua). Recently there has been speculation that the release of lobster from predatory control may have resulted in both lower predation rates and increased foraging areas. We used fine-scale acoustic telemetry within a 200 m × 250 m field enclosure to test the hypothesis that cod induce lobsters to decrease movement and seek refuge. We found a large amount of variation in the behavioral response of individual lobsters to predators; however, the addition of cod into the enclosure reduced maximum daily home range area and significantly reduced the distance traveled from shelter habitat area for all individuals. When predators were removed from the enclosure, lobsters responded by increasing home range area and significantly increasing the distance traveled from shelter habitat area. These results represent the first experimental evidence for American lobster range contraction and subsequent expansion in the presence and absence of cod, respectively.

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