Spring habitat use by stocked one year old European sturgeon Acipenser sturio in the freshwater-oligohaline area of the Gironde estuary

Habitat use and growth of juvenile (8–90 mm carapace length, or CL) ornate rock lobsters, Panulirus ornatus, were described with the aid of information from field surveys in Torres Strait and from a laboratory growth experiment. In north-western Torres Strait, small juveniles (<40 mm CL) sheltered in solution holes in the seabed that matched their body size. Most shelters were in limestone pavement and near macroalgae. Larger juveniles sheltered in both solution holes and crevices. Juveniles were found at all depths sampled (3–21 m), and densities of juveniles were uniform over this depth range. The average density of juveniles in the study area in 1992–93 was 63 ha-1. Size distributions of juveniles sampled during August 1992 to March 1993 showed that early growth was 1·4 mm CL week-1. A laboratory trial to examine the effect of temperature on growth showed that juveniles grew 31% faster at 30°C (0·88 mm CL week-1) compared with growth at 26°C (0·67 mm CL week-1) as a result of shorter moult intervals in large juveniles. Size distributions of juveniles sampled at mid year between 1990 and 1995 showed that 10–20% reach legal size (75 mm CL) about one year after settlement.

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Severe decline in Cantabrian Capercaillie Tetrao urogallus cantabricus habitat use after construction of a wind farm

Bird Conservation International ◽

10.1017/s0959270914000471 ◽

2015 ◽

Vol 26 (2) ◽

pp. 256-261 ◽

Cited By ~ 3

Author(s):

MANUEL A. GONZÁLEZ ◽

SERGIO GARCÍA-TEJERO ◽

ERIC WENGERT ◽

BENITO FUERTES

Keyword(s):

Habitat Use ◽

Wind Farm ◽

Tetrao Urogallus ◽

Mediterranean Forests ◽

Cantabrian Mountains ◽

Conservation Areas ◽

North West ◽

Negative Effect ◽

Tetrao Urogallus Cantabricus ◽

One Year

SummaryTetrao urogallus cantabricus is the most endangered capercaillie subspecies and unlike the others it inhabits deciduous forests in the Cantabrian Mountains (north-west Spain). Its southernmost distribution occurs in Mediterranean forests outside conservation areas where wind farm construction is increasing. We surveyed Cantabrian Capercaillie presence in a wintering site one year before and four years after wind farm construction. Sign abundance greatly decreased after wind farm construction indicating a likely negative effect on Cantabrian Capercaillie habitat use. According to the precautionary principle, in order to conserve Cantabrian Capercaillie, all its range should be legally protected to avoid further wind farm construction and human disturbance.

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Marine habitat use and feeding ecology of introduced anadromous brown trout at the colonization front of the sub-Antarctic Kerguelen archipelago

Scientific Reports ◽

10.1038/s41598-021-91405-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jan Grimsrud Davidsen ◽

Xavier Bordeleau ◽

Sindre Håvarstein Eldøy ◽

Frederick Whoriskey ◽

Michael Power ◽

...

Keyword(s):

Habitat Use ◽

Brown Trout ◽

Foraging Ecology ◽

Good Condition ◽

Stomach Contents ◽

Suitable Habitat ◽

Marine Habitat ◽

Resource Needs ◽

One Year ◽

Kerguelen Archipelago

AbstractIn 1954, brown trout were introduced to the Kerguelen archipelago (49°S, 70°E), a pristine, sub-Antarctic environment previously devoid of native freshwater fishes. Trout began spreading rapidly via coastal waters to colonize adjacent watersheds, however, recent and unexpectedly the spread has slowed. To better understand the ecology of the brown trout here, and why their expansion has slowed, we documented the marine habitat use, foraging ecology, and environmental conditions experienced over one year by 50 acoustically tagged individuals at the colonization front. Trout mainly utilized the marine habitat proximate to their tagging site, ranging no further than 7 km and not entering any uncolonized watersheds. Nutritional indicators showed that trout were in good condition at the time of tagging. Stomach contents and isotope signatures in muscle of additional trout revealed a diet of amphipods (68%), fish (23%), isopods (6%), and zooplankton (6%). The small migration distances observed, presence of suitable habitat, and rich local foraging opportunities suggest that trout can achieve their resource needs close to their home rivers. This may explain why the expansion of brown trout at Kerguelen has slowed.

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Population status and habitat use of southern right whales in the sub-Antarctic Auckland Islands of New Zealand

J. Cetacean Res. Manage. ◽

10.47536/jcrm.vi.274 ◽

2020 ◽

pp. 111-116

Author(s):

Nathalie J. Patenaude ◽

C. Scott Baker

Keyword(s):

New Zealand ◽

Habitat Use ◽

Molecular Sexing ◽

Right Whales ◽

The Status ◽

Southern Right Whales ◽

Major Shift ◽

Cow Calf ◽

High Concentrations ◽

One Year

In the winters of 1995, 1996 and 1997, research was conducted in the Auckland Islands to evaluate the status of southern right whales inthe New Zealand sub-Antarctic. Whales were present in high concentrations each year (maximum count of 146 whales) in a small area onthe northeast side of the main island. Cow-calf pairs averaged 12% (range 9% to 14%) of the total population. Most cow-calf pairs weresighted resting at the surface (60%) or travelling (36%) and showed a strong preference for shallow ( < 20m depth) nearshore waters. Theratio of females to males, as determined by molecular sexing using biopsy samples, varied from 54% to 39% over the three years but didnot differ significantly from 1:1 in any year. Both males and females were found in varying group sizes, with the occurrence of social/sexualactivity predominant (85%) in groups of three or more whales. Most single whales were found resting (59%) and occasionally approachedthe research vessel (19%). A total of 217 individual whales have been photo-identified over the three years of this study, 24% of which wereresighted more than once in a season and approximately 15% of which were resighted in more than one year. The high density of whalesin Port Ross during winter months, the presence of cow-calf pairs, including newborns, and the frequency of social and sexual activityindicates that the Auckland Islands are a primary wintering habitat for southern right whales in New Zealand waters. However, the lowresighting rates within season and documented movement to nearby Campbell Island (290km) suggest that some whales are not residentin the Auckland Islands throughout the season. The rarity of right whales along the main islands of New Zealand and their apparent increasein numbers in the Auckland Islands suggests a major shift in habitat use from pre-exploitation times or the loss of a component of ahistorically sub-divided stock.

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Movements and habitat use of the invasive species Lithobates catesbeianus in the valley of the Grote Nete (Belgium)

Belgian Journal of Zoology ◽

10.26496/bjz.2016.44 ◽

2020 ◽

Vol 146 (2) ◽

Cited By ~ 1

Author(s):

Sarah Descamps ◽

Alain De Vocht

Keyword(s):

Invasive Species ◽

Home Range ◽

Habitat Use ◽

Lithobates Catesbeianus ◽

Radio Transmitter ◽

American Bullfrog ◽

The Mean ◽

One Year ◽

Eutrophic Ponds ◽

Alluvial Forest

Nine adult American bullfrogs (Lithobates catesbeianus) were tagged with an internal radio transmitter and tracked during one year in the valley of the Grote Nete (Belgium). The mean ± SD core range area (KDE50) was 15.00 ± 22.41m2. The home range area (KDE95) had a mean ± SD of 429.78 ± 510.97m2. Shores of larger eutrophic ponds and small temporary pools in alluvial forest were chosen as habitat. The total area used (MCP95) had a mean of 11,086.73 ± 12,239.00m2. The study revealed a mean action radius of 270.78 ± 199.17m and individuals moved up to 742m in a single displacement. These results show that the dispersion of the American bullfrog in a valley system such as the Grote Nete can proceed very rapidly. A positive correlation between weight and distance covered within one movement was found, which could suggest that dominant individuals are capable of covering greater distances in search of optimal habitat for reproduction, foraging or hibernation.

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