The Recent Range Expansion of Great Cormorants Phalacrocorax carbo in Hokkaido, Japan

Squires, Theodore E.; Aoki, Daisuke; Hasegawa, Osamu

doi:10.5253/arde.v109i2.a11

Cited by 5 publications

(11 citation statements)

References 7 publications

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“…The relationship between the prey harvest rate and the predator stocking rate could be driven by the predator-prey relationship between the catfish and the rheophilic fishes. In central Europe, catfish predation is further combined with predation by otters Lutra lutra (Linnaeus, 1758), cormorants Phalacrocorax carbo (Linnaeus, 1758), and gray herons Ardea Cinerea (Linnaeus, 1758) [7,36]. River damming, water pollution (mainly organic pollution and microplastics), and removal of hideouts further pressure the rheophilic fish populations [8][9][10]21].…”

Section: Discussionmentioning

confidence: 99%

“…The rheophilic fishes are a fish species that prefer to live, hunt, and reproduce in fast-moving waters. Their populations are decreasing due to anthropogenic actions-mainly river fragmentation, removal of shelters and spawning sites, water pollution, protection of piscivorous cormorants and otters, and angling pressure [7][8][9][10]. Despite intensive stocking efforts, a reintroduction of the rheophilic fishes failed to stabilize their populations in central Europe due to river fragmentation and poor environmental conditions [11].…”

Section: Introductionmentioning

confidence: 99%

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Harvest Rates of Rheophilic Fish Vimba vimba, Chondrostoma nasus, and Barbus barbus Have a Strong Relationship with Restocking Rates and Harvest Rates of Their Predator Silurus glanis in Lowland Mesotrophic Rivers in Central Europe

Lyach

2021

Sustainability

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The European catfish Silurus glanis (Linnaeus, 1758) is an expanding apex piscivorous predator whose predation may drive fish harvest rates and fish populations. This study aimed to analyze the relationships between intensive catfish stocking/harvesting and harvest rates of putative catfish prey–three rheophilic fish species: vimba bream Vimba vimba, nase Chondrostoma nasus, and barbel Barbus barbus (Linnaeus, 1758). The GAM (generalized additive model) was used to analyze the relationships between the harvest rate and the stocking intensity rate of the catfish and the three rheophilic fish species. The harvest rates and stocking intensity rates were obtained from mandatory angling logbooks collected from 38,000 individual recreational anglers by the Czech Fishing Union on 176 fishing sites over the years 2005–2017 in central Bohemia and Prague (the Czech Republic). Our results show that a higher intensity of catfish stocking and harvesting resulted in a lower harvest rate of rheophilic fishes. Conversely, the stocking rates of rheophilic fishes were not significantly correlated to their harvest rates. In conclusion, a significant negative relationship was found between the harvest rate and the restocking rates of rheophilic fishes and their predator, suggesting that fisheries managers should not perform intensive stocking of both catfish and rheophilic fishes on the same rivers.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Harvest Rates of Rheophilic Fish Vimba vimba, Chondrostoma nasus, and Barbus barbus Have a Strong Relationship with Restocking Rates and Harvest Rates of Their Predator Silurus glanis in Lowland Mesotrophic Rivers in Central Europe

Lyach

2021

Sustainability

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“…Tissue samples for genetic analyses based on microsatellites were taken from the pectoral muscle. Newson et al (2004Newson et al ( , 2005 examined several morphological characteristics for distinguishing between the subspecies of P. carbo in Europe. The gular pouch angle was found to be significantly different between the carbo subspecies (GPA ≤ 65°) and the sinensis subspecies (GPA ≥ 73°), but individuals with intermediate morphology (GPA = 66-72°) could not be identified to subspecies with certainty.…”

Section: Methodsmentioning

confidence: 99%

“…The GPA method can be used to identify the two subspecies of cormorants from observations or photos of live birds, and dead birds which were drowned in nets or shot. However, there is a range of angles which overlap between the two subspecies (Alström 1985, Newson et al 2004. In the case of dead individuals with intermediate GPA values, the subspecies can also be identified using other biometrical measurements (Newson et al 2004(Newson et al , 2005.…”

Section: Introductionmentioning

confidence: 99%

“…However, there is a range of angles which overlap between the two subspecies (Alström 1985, Newson et al 2004. In the case of dead individuals with intermediate GPA values, the subspecies can also be identified using other biometrical measurements (Newson et al 2004(Newson et al , 2005. However, potential hybridisation between the subspecies may weaken the accuracy of the gular pouch angle method.…”

Section: Introductionmentioning

confidence: 99%

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Combining biometrics and genetics to distinguish two subspecies of the Great Cormorant Phalacrocorax carbo carbo and P. c. sinensis at an inland lake in southeast Norway

Grøndahl,

Johnsen

2024

Ornis Norv.

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Cover photo: Adult Great Cormorant of the subspecies Phalacrocorax carbo sinensis in breeding plumage. Photo: Frode Falkenberg. Great Cormorants Phalacrocorax carbo are now regularly seen in inland watercourses in southeast Norway, after the P. c. sinensis subspecies first established breeding colonies in coastal south Norway in 1996. Although both the sinensis and carbo subspecies occur, the ratio between them is unknown. We tested the accuracy of subspecific identification based on biometrics and genetic analyses in 75 Great Cormorants that drowned in fishing nets in a lake in southeast Norway during the period 2009-2020. Primarily based on the gular pouch angle (GPA), we classified 40 individuals to the carbo subspecies and 35 individuals to the sinensis subspecies. Eight of the carbo individuals and 14 of the sinensis individuals were within the overlapping range of GPA and were therefore classified to subspecies by supplementary measurements (bill depth minimum and bill length). Genetic analyses were based on seven polymorphic microsatellite markers. Assuming one panmictic population, we performed Structure analyses to separate the genotypes into two assumed genetic clusters. The two clusters, carbo and sinensis, could only be separated when adding information about morphological subspecies identities for the carbo, sinensis and carbo/sinensis groups. The sinensis and the carbo/sinensis groups belonged almost entirely to one genetic cluster, whereas the carbo group consisted of individuals with varying proportions of mixed ancestry. Furthermore, we found significant genetic differentiation between the carbo and sinensis groups, and between the carbo and the carbo/sinensis groups, but no significant differentiation between the sinensis and the carbo/sinensis groups. Our results suggest that gene flow is more common from sinensis into carbo than vice-versa, and that the use of GPA < 73° has limitations for the identification of Great Cormorant subspecies in areas where both forms occur. We conclude that the numbers of carbo vs. sinensis individuals in our sample were 32 and 43, respectively.

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Exploring predators of Pacific salmon throughout their life history: the case of Japanese chum, pink, and masu salmon

Okado,

Hasegawa

2024

Rev Fish Biol Fisheries

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The Recent Range Expansion of Great Cormorants Phalacrocorax carbo in Hokkaido, Japan

Cited by 5 publications

References 7 publications

Harvest Rates of Rheophilic Fish Vimba vimba, Chondrostoma nasus, and Barbus barbus Have a Strong Relationship with Restocking Rates and Harvest Rates of Their Predator Silurus glanis in Lowland Mesotrophic Rivers in Central Europe

Harvest Rates of Rheophilic Fish Vimba vimba, Chondrostoma nasus, and Barbus barbus Have a Strong Relationship with Restocking Rates and Harvest Rates of Their Predator Silurus glanis in Lowland Mesotrophic Rivers in Central Europe

Combining biometrics and genetics to distinguish two subspecies of the Great Cormorant Phalacrocorax carbo carbo and P. c. sinensis at an inland lake in southeast Norway

Exploring predators of Pacific salmon throughout their life history: the case of Japanese chum, pink, and masu salmon

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