Contrasting patterns of residency and space use of coastal sharks within a communal shark nursery

2017 ◽  
Vol 68 (8) ◽  
pp. 1501 ◽  
Author(s):  
Beverly Z. L. Oh ◽  
Michele Thums ◽  
Russ C. Babcock ◽  
Jessica J. Meeuwig ◽  
Richard D. Pillans ◽  
...  
Keyword(s):  
Marine Protected Areas ◽  
Space Use ◽  
Tidal Range ◽  
Northern Australia ◽  
Small Areas ◽  
Mobile Species ◽  
Brownian Bridges ◽  
Selection For ◽  
Carcharhinus Melanopterus ◽  
Derived Data

The benefits of marine protected areas are difficult to estimate for mobile species, but their effectiveness can be increased if essential habitats, such as nursery areas, are protected. In the present study we examined movements of juvenile blacktip reef (Carcharhinus melanopterus) and sicklefin lemon (Negaprion acutidens) sharks in a coastal nursery in northern Australia. Telemetry-derived data were modelled using Brownian bridges and overlaid with maps of habitats and no-take zones. Juvenile N. acutidens were typically residents (≥30 days) of the nursery with small areas of core space use (<1.9km2), whereas juvenile C. melanopterus were non-residents (<30 days) and used larger areas (<5.6km2). Both species exhibited positive selection for sandflats and mangroves, and avoidance of deeper lagoonal and slope habitats. Monthly patterns were examined only for resident N. acutidens, and residency decreased with increasing shark length and varied seasonally for males but not females. Space use showed weak declines with increasing tidal range, and slight increases with mean air pressure, rainfall and shark length. Protecting sandflat and vegetated habitats may increase the efficacy of no-take zones for juvenile N. acutidens, because they exhibit residency and affinity to these features. Conversely, such protection will be of limited benefit for juvenile C. melanopterus, because they exhibit low residency and broader movements.

The extent of Mission grasses and Gamba Grass in the Darwin region of Australia's Northern Territory

2002 ◽  
Vol 8 (4) ◽  
pp. 281 ◽  
Author(s):  
Louise Kean ◽  
Owen Price
Keyword(s):  
Land Tenure ◽  
Hot Spots ◽  
Northern Australia ◽  
Weed Species ◽  
Small Areas ◽  
Major Threat ◽  
Potential Habitat ◽  
Potential Source ◽  
Andropogon Gayanus ◽  
Prompt Action

Mission grasses Pennisetum polystachion (L.) Schult. and P. pedicellatum (Trin) and Gamba Grass Andropogon gayanus (Kunth) are three weed species that are thought to be spreading rapidly in the vicinity of Darwin and may pose a major threat to ecosystems in northern Australia. The distribution of the species was assessed from a vehicle along 913 km of roads near Darwin. The study provided data on the potential source of further spread and an analysis of the potential habitat of the weeds. For analysis, roadsides were divided up into 200 m cells and the distributions of the grasses were compared against land tenure and broad land unit maps, Mission grasses were present in approximately 52% of cells, and were particularly common around the rural residential/horticultural area of Humpty Doo. They occurred equally commonly in all broad land units, but differed among tenures, being particularly common on freehold land. Gamba Grass occurred in 15% of cells, with hot spots in a number of areas. It was most common on freehold land, and was rare on conservation reserves. It also showed an association with broad land units reflecting wetter areas. Mission grasses are so widespread in the Darwin region that control can only be contemplated in very small areas requiring frequent treatment of re-invading plants. It may be possible to control Gamba Grass in conservation reserves and Crown land if prompt action is taken. For all three species, preventing their spread to new areas should be a high priority.

Persistence of mobile species in marine protected areas

2008 ◽  
Vol 91 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Urmila Malvadkar ◽  
Alan Hastings
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Mobile Species

scholarly journals TEST RESULTS FOR CLONES OF GARLIC

2018 ◽  
pp. 11-12
Author(s):  
B. S. Salomov ◽  
M. H. Aramov
Keyword(s):  
Selection Process ◽  
Test Results ◽  
Tropical Regions ◽  
Small Areas ◽  
State Register ◽  
New Varieties ◽  
Selection For ◽  
The Republic ◽  
High Yielding Varieties ◽  
Almost All

A large number of forms and varieties of garlic created in the selection process allowed this culture to spread almost all over the world: in temperate regions, in subtropics and even in tropical regions. Currently, the world's acreage of garlic is 1.438 million hectares, the average yield is 16.9 tons per hectare, the gross yield is 24.255 million tons. The largest producers of garlic are China, India, South Korea and Egypt. The highest yield was recorded in Uzbekistan, Egypt, China, Tadjikistan. In Uzbekistan, it is grown everywhere, mainly on household plots and small areas in farms. In the republic, varieties of garlic are South-violet (1972) and May VIR (1978). Since 2004, the Surkhandarya Scientific Experimental Station of the VegetableMelon Crops and Potato Research Institute has been conducting selection work to create new varieties of garlic. As a result of the research, the Chidamli variety was introduced and, since 2016, introduced into the State Register. All zoned varieties belong to the group of autumn-sprouting varieties. In 2011- 2015, about 100 promising clones of garlic were evaluated in the south of Uzbekistan. The effectiveness of selection for the size of bulbs and teeth is revealed. Clones with a mass of bulbs and teeth are isolated. Clones with a bulb weight of more than 80 g and a tooth mass of more than 6 g are distinguished. They are a valuable source for the creation of high-yielding varieties of garlic in Uzbekistan.

scholarly journals Managing mobile species with MPAs: the effects of mobility, larval dispersal, and fishing mortality on closure size

2008 ◽  
Vol 66 (1) ◽  
pp. 122-131 ◽  
Author(s):  
W. J. F. Le Quesne ◽  
Edward A. Codling
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Larval Dispersal ◽  
Population Model ◽  
Marine Reserves ◽  
Spatially Explicit ◽  
Fishing Mortality ◽  
Mobile Species ◽  
Explicit Dynamic ◽  
Dynamic Population

Abstract Le Quesne, W. J. F., and Codling, E. A. 2009. Managing mobile species with MPAs: the effects of mobility, larval dispersal, and fishing mortality on closure size. – ICES Journal of Marine Science, 66: 122–131. The use of closed areas (marine protected areas, marine reserves, no-take zones) has been suggested as a possible solution to the perceived global fisheries crisis. However, to optimize the design and evaluate the effectiveness of closed areas, we need to understand the interaction between larval dispersal, adult mobility, and fishing mortality. In this paper, a simple, spatially explicit dynamic population model was developed to examine the effects of these interacting factors on optimal closure size and resulting yields. The effect of using one large or several smaller closed areas was also examined. Our model confirmed previous results: closed areas do not improve the yield of populations that are optimally managed or underexploited and, as mobility increases, optimum closure size increases. The model also predicted some interesting counter-intuitive results; for overexploited stocks, the greatest benefit from closed areas can be obtained for stocks with highest mobility, although this may require closure of 85% of the total area. For the tested parameter settings, adult spillover had greater potential to improve yield than larval export, and using several small closed areas rather than a single larger one had the same effect as increasing the mobility of the population.

No-trawl area impacts: perceptions, compliance and fish abundances

2012 ◽  
Vol 39 (3) ◽  
pp. 237-247 ◽  
Author(s):  
H.J. BLOOMFIELD ◽  
C.J. SWEETING ◽  
A.C. MILL ◽  
S.M. STEAD ◽  
N.V.C. POLUNIN
Keyword(s):  
High Mobility ◽  
Fishing Effort ◽  
Fish Abundance ◽  
Management Tool ◽  
Small Areas ◽  
Abundance Data ◽  
Mobile Species ◽  
Baited Traps ◽  
Fish Abundances ◽  
Size Data

SUMMARYMPAs are being established worldwide at an increasing rate, however empirical evidence for benefits to mobile species of small areas closed to fishing in temperate regions are little known. Using two North Sea prohibited trawling areas (PTAs) established > 80 years ago, social (fishers’ perceptions), management (fishing effort and compliance) and ecological (fish abundance and size) data were combined to assess the PTAs against their primary societal (conflict resolution) and secondary ecological (stock protection) objectives. Fishers perceived that the PTAs resolved conflicts between static and mobile gear sectors, despite evidence of non-compliance. However, few fishers perceived that they personally benefited from the PTAs. Fish abundance and size data from baited traps (BT) and video (BV) provided no evidence of PTA effects, but trawling effort was a significant predictor of BT fish abundance data and improved the model of BV fish abundance data. The absence of PTA effects on fish is attributable to non-compliance, the high mobility of the fish involved and their continued exploitation within the PTAs using static gear. This points to the need for greater understanding of the behaviour of fishers in relation to closures. The study also highlights the challenges of quantifying possible fishery benefits of small temperate closed areas and questions whether widely advocated fishery benefits may have enhanced initial support, but failure to deliver them may erode faith in such closures as a fisheries management tool.

scholarly journals Restricted constrictors: Space use and habitat selection of native Burmese pythons in Northeast Thailand

2020 ◽  
Author(s):  
Samantha Nicole Smith ◽  
Max Dolton Jones ◽  
Benjamin Michael Marshall ◽  
Surachit Waengsothorn ◽  
George A. Gale ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Animal Movement ◽  
Brownian Bridge ◽  
Radio Telemetry ◽  
Space Use ◽  
Population Level ◽  
Human Settlements ◽  
Small Areas ◽  
Agricultural Conversion ◽  
Selection Of

AbstractAnimal movement and resource use are tightly linked. Investigating these links to understand how animals utilize space and select habitats is especially relevant in areas that have been affected by habitat fragmentation and agricultural conversion. We set out to explore the space use and habitat selection of Burmese pythons (Python bivittatus) in a patchy land use matrix dominated by agricultural crops and human settlements. We used radio telemetry to record daily locations of seven Burmese pythons over the course of our study period of approximately 22 months. We created dynamic Brownian Bridge Movement Models (dBBMMs) for all individuals, using occurrence distributions to estimate extent of movements and motion variance to reveal temporal patterns. Then we used integrated step selection functions to determine whether individual movements were associated with particular landscape features (aquatic agriculture, forest, roads, settlements, terrestrial agriculture, water), and whether there were consistent associations at the population level. Our dBBMM estimates suggested that Burmese pythons made use of small areas (98.97 ± 35.42 ha), with low mean individual motion variance characterized by infrequent moves and long periods at a single location. At both the individual and population level, Burmese pythons in the agricultural matrix were associated with aquatic environments. Only one individual showed a strong avoidance for human settlements which is troublesome from a human-wildlife conflict angle, especially as Burmese pythons have been observed entering human settlements and consuming livestock in our study site. Our study is one of the first to contribute to the knowledge of Burmese python ecology in their native range as the majority of studies have focused on invasive populations.

Conservation Criminology: Modelling Offender Target Selection for Illegal Fishing in Marine Protected Areas

2019 ◽  
Vol 59 (6) ◽  
pp. 1455-1477 ◽  
Author(s):  
Damian P Weekers ◽  
Renee Zahnow ◽  
Lorraine Mazerolle
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Target Selection ◽  
Environmental Criminology ◽  
Wildlife Crime ◽  
The Past ◽  
Marine Park ◽  
Regional Population ◽  
Selection For ◽  
Insight Into

AbstractThe emergence of conservation criminology over the past decade provides a unique insight into patterns of wildlife crime. Wildlife crime has a dramatic impact on many vulnerable species and represents a significant challenge to the management of protected areas around the world. This paper contributes to the field of conservation criminology by examining the travel patterns of fishing poachers in the Great Barrier Reef Marine Park in Australia. The results demonstrate that distance is a key feature of offender target selection, reflecting the established environmental criminology concept of distance decay. The analysis also reveals a significant relationship between individual no-take zones and regional population areas. The applicability of a nodal-oriented approach to wildlife crime prevention is discussed.

Space use by white-headed woodpeckers and selection for recent forest disturbances

2015 ◽  
Vol 79 (8) ◽  
pp. 1286-1297 ◽  
Author(s):  
Teresa J. Lorenz ◽  
Kerri T. Vierling ◽  
Jeffrey M. Kozma ◽  
Janet E. Millard ◽  
Martin G. Raphael
Keyword(s):  
Space Use ◽  
Forest Disturbances ◽  
Selection For

Shark and ray community structure in a turbid, nearshore coral reef habitat

2020 ◽  
Vol 71 (9) ◽  
pp. 1194 ◽  
Author(s):  
Arthur Yon ◽  
Mark G. Meekan ◽  
Samantha Andrzejaczek ◽  
Sarah Martinez ◽  
Conrad W. Speed
Keyword(s):  
Austral Summer ◽  
Common Species ◽  
Northern Australia ◽  
Underwater Video ◽  
Reef Habitat ◽  
Management Zones ◽  
Marine Park ◽  
Abundance And Diversity ◽  
Carcharhinus Melanopterus ◽  
Coral Reef Habitat

The coastline of northern Australia may be a refuge for elasmobranchs threatened or extirpated from much of their former ranges across South-East Asia. In this study, we used baited remote underwater video stations to survey the abundance, size and assemblage of elasmobranchs in the Cobourg Marine Park in northern Australia. Two sites were sampled inside the park and one site was sampled outside the park, covering two management zones: open and partially protected. During the austral summer, 85 individuals of 12 species of elasmobranch were observed over 12 days. No significant differences were observed among sites in either size or abundance for common species. Videos were dominated by Carcharhinus melanopterus (relative abundance±s.d., 0.29±0.90h–1), Nebrius ferrugineus (0.03±0.24h–1) and Urogymnus granulatus (0.08±0.28h–1), which comprised &gt;81% of all individuals. Environmental variables had no measurable effect on the abundance of elasmobranchs. The abundance and diversity of elasmobranchs in Cobourg Marine Park is high compared with other similar turbid, inshore areas of northern Australia. The large number of juveniles observed in our surveys also suggests the possibility of a nursery area.

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