Stock structure of Lethrinus laticaudis (Lethrinidae) across northern Australia determined using genetics, otolith microchemistry and parasite assemblage composition

2018 ◽  
Vol 69 (4) ◽  
pp. 487 ◽  
Author(s):  
Diane P. Barton ◽  
Laura Taillebois ◽  
Jonathan Taylor ◽  
David A. Crook ◽  
Thor Saunders ◽  
...  
Keyword(s):  
Isolation By Distance ◽  
Spatial Scales ◽  
Distance Effect ◽  
Fishing Effort ◽  
Northern Territory ◽  
Otolith Microchemistry ◽  
Stock Structure ◽  
Northern Australia ◽  
Complementary Techniques ◽  
Population Genetic Analyses

The grass emperor Lethrinus laticaudis is a conspicuous element of the commercial and recreational catch from nearshore reef systems across northern Australia. The nearshore reef systems across northern Australia are exposed to increasing levels of fishing pressure from commercial and recreational fishers. To inform ongoing management of this species, the present study examined the stock structure of L. laticaudis across northern Australia using a combination of complementary techniques. In all, 342 L. laticaudis samples were collected from 13 locations in the coastal waters of northern Australia ranging from the Pilbara region of Western Australia to Moreton Bay in south-east Queensland. Population genetic analyses using microsatellite markers demonstrated that there were at least four genetically distinct populations across northern Australia with gene flow between management jurisdictions (with significantly more separation between Western Australian and Northern Territory locations than between Northern Territory and Queensland locations). An isolation by distance effect was evident (genetic differences increasing linearly with distance). Otolith microchemistry and parasitology analyses indicated some spatial structuring of populations within broader regions. These findings of restricted connectivity at small spatial scales suggest that L. laticaudis is vulnerable to localised depletion in areas where fishing effort is concentrated. This conclusion is consistent with recent observations of fishery declines in heavily fished locations.

Contemporary fire regimes of northern Australia, 1997 - 2001: change since Aboriginal occupancy, challenges for sustainable management

2003 ◽  
Vol 12 (4) ◽  
pp. 283 ◽  
Author(s):  
Jeremy Russell-Smith ◽  
Cameron Yates ◽  
Andrew Edwards ◽  
Grant E. Allan ◽  
Garry D. Cook ◽  
...  
Keyword(s):  
National Parks ◽  
Fire Regime ◽  
Spatial Scales ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Northern Territory ◽  
Frequency Interval ◽  
Northern Australia ◽  
Noaa Avhrr ◽  
Fine Resolution

Considerable research has been undertaken over the past two decades to apply remote sensing to the study of fire regimes across the savannas of northern Australia. This work has focused on two spatial scales of imagery resolution: coarse-resolution NOAA-AVHRR imagery for savanna-wide assessments both of the daily distribution of fires ('hot spots'), and cumulative mapping of burnt areas ('fire-scars') over the annual cycle; and fine-resolution Landsat imagery for undertaking detailed assessments of regional fire regimes. Importantly, substantial effort has been given to the validation of fire mapping products at both scales of resolution. At the savanna-wide scale, fire mapping activities have established that: (1) contrary to recent perception, from a national perspective the great majority of burning in any one year typically occurs in the tropical savannas; (2) the distribution of burning across the savannas is very uneven, occurring mostly in sparsely settled, higher rainfall, northern coastal and subcoastal regions (north-west Kimberley, Top End of the Northern Territory, around the Gulf of Carpentaria) across a variety of major land uses (pastoral, conservation, indigenous); whereas (3) limited burning is undertaken in regions with productive soils supporting more intensive pastoral management, particularly in Queensland; and (4) on a seasonal basis, most burning occurs in the latter half of the dry season, typically as uncontrolled wildfire. Decadal fine-resolution fire histories have also been assembled from multi-scene Landsat imagery for a number of fire-prone large properties (e.g. Kakadu and Nitmiluk National Parks) and local regions (e.g. Sturt Plateau and Victoria River District, Northern Territory). These studies have facilitated more refined description of various fire regime parameters (fire extent, seasonality, frequency, interval, patchiness) and, as dealt with elsewhere in this special issue, associated ecological assessments. This paper focuses firstly on the patterning of contemporary fire regimes across the savanna landscapes of northern Australia, and then addresses the implications of these data for our understanding of changes in fire regime since Aboriginal occupancy, and implications of contemporary patterns on biodiversity and emerging greenhouse issues.

Where do we draw the line? A simulation approach for evaluating management of marine fish stocks with isolation-by-distance stock structure

2015 ◽  
Vol 72 (7) ◽  
pp. 968-982 ◽  
Author(s):  
Ingrid Spies ◽  
Paul D. Spencer ◽  
André E. Punt
Keyword(s):  
Marine Fish ◽  
Isolation By Distance ◽  
Management Strategies ◽  
Marine Species ◽  
Fishing Effort ◽  
Stock Structure ◽  
Pacific Cod ◽  
Entire Area ◽  
Lower Productivity ◽  
Management Protocol

There is no established management protocol for stocks subject to isolation-by-distance (IBD) stock structure. This study examines several management strategies for two marine fish species subject to IBD using simulation: Pacific cod (Gadus macrocephalus) in the Aleutian Islands (AI) and northern rockfish (Sebastes polyspinis) in the Eastern Bering Sea (EBS) and AI. A one-dimensional stepping stone model was used to model IBD and was intended to mimic regions where marine species are exploited along a continental shelf. The performance of spatial assessment and management methods depended on how the range was split. Splitting anywhere within the managed area led to fewer demes falling below target and threshold biomass levels and higher yield than managing the entire area as a single unit. Equilibrium yield was maximized when each deme was assessed and managed separately and under catch cascading, in which harvest quotas within a management unit are spatially allocated based upon the distribution of survey biomass. The longer-lived rockfish declined more slowly than Pacific cod and experienced greater depletion in biomass under disproportionate fishing effort because of lower productivity. Overall, splitting a management area of the size simulated in the model improved performance measures, and the optimal management strategy grouped management units by demes with similar relative fishing effort.

Genetic isolation by distance and localized fjord population structure in Pacific cod (Gadus macrocephalus): limited effective dispersal in the northeastern Pacific Ocean

2009 ◽  
Vol 66 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Kathryn Maja Cunningham ◽  
Michael Francis Canino ◽  
Ingrid Brigette Spies ◽  
Lorenz Hauser
Keyword(s):  
Population Structure ◽  
Pacific Ocean ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Puget Sound ◽  
Pacific Cod ◽  
Genetic Population ◽  
Pacific Cod Gadus Macrocephalus ◽  
Gadus Macrocephalus ◽  
Northeastern Pacific

Genetic population structure of Pacific cod, Gadus macrocephalus , was examined across much of its northeastern Pacific range by screening variation at 11 microsatellite DNA loci. Estimates of FST (0.005 ± 0.002) and RST (0.010 ± 0.003) over all samples suggested that effective dispersal is limited among populations. Genetic divergence was highly correlated with geographic distance in an isolation-by-distance (IBD) pattern along the entire coastal continuum in the northeastern Pacific Ocean (~4000 km; r2 = 0.83), extending from Washington State to the Aleutian Islands, and over smaller geographic distances for three locations in Alaska (~1700 km; r2 = 0.56). Slopes of IBD regressions suggested average dispersal distance between birth and reproduction of less than 30 km. Exceptions to this pattern were found in samples taken from fjord environments in the Georgia Basin (the Strait of Georgia (Canada) and Puget Sound (USA)), where populations were differentiated from coastal cod. Our results showed population structure at spatial scales relevant to fisheries management, both caused by limited dispersal along the coast and by sharp barriers to migration isolating smaller stocks in coastal fjord environments.

scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

Stock structure of blue threadfin Eleutheronema tetradactylum across northern Australia, as indicated by parasites

2011 ◽  
Vol 78 (3) ◽  
pp. 923-936 ◽  
Author(s):  
B. R. Moore ◽  
J. Stapley ◽  
Q. Allsop ◽  
S. J. Newman ◽  
A. Ballagh ◽  
...  
Keyword(s):  
Stock Structure ◽  
Northern Australia

scholarly journals Sensing the Same Fishing Fleet with AIS and VIIRS: A Seven-Year Assessment of Squid Jiggers in FAO Major Fishing Area 41

2019 ◽  
Vol 12 (1) ◽  
pp. 32
Author(s):  
Javier Ruiz ◽  
Isabel Caballero ◽  
Gabriel Navarro
Keyword(s):  
Infrared Imaging ◽  
Spatial Scales ◽  
Fishing Effort ◽  
Automatic Identification ◽  
Identification System ◽  
Sources Of Information ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
High Degree ◽  
Fishing Area

Global Fishing Watch and VIIRS-DNB (visible infrared imaging radiometer suite day/night band) signals are compared for the jigger fleet in FAO (Food and Agriculture Organization of the United Nations) Major Fishing Area 41 during the maximum feasible time span (2012–2018). Both signals have shown a high degree of consistency at all temporal and spatial scales analyzed, including seasonal cycles, lack of signal for some years and interannual tendencies. This indicates that both signals are a fair representation of the fishing effort exerted by the jigger fleet in this zone. The high degree of consistency does not support views questioning satellite AIS (automatic identification system) as a reliable tool to survey fishing activities. Instead, our results add evidence supporting the value of remote sensing, in particular, when independent sources of information (such as VIIRS-DNB and AIS) are combined, as a relevant tool to add transparency and support compliance of fishing activities in vast and distant regions of the ocean.

Genotyping-by-sequencing reveals genomic homogeneity among overwintering Pacific Dunlin (Calidris alpina pacifica) aggregations along the Pacific coast of North America

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Iva Popovic ◽  
David P L Toews ◽  
Carson C Keever ◽  
C Toby St. Clair ◽  
Blake A Barbaree ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
River Estuary ◽  
Genotyping By Sequencing ◽  
Genomic Diversity ◽  
Nucleotide Polymorphisms ◽  
Migratory Connectivity ◽  
Calidris Alpina ◽  
The Pacific

Abstract Information on how migratory populations are genetically structured during the overwintering season of the annual cycle can improve our understanding of the strength of migratory connectivity and help identify populations as units for management. Here, we use a genotype-by-sequencing approach to investigate whether population genetic structure exists among overwintering aggregations of the Pacific Dunlin subspecies (Calidris alpina pacifica) sampled at 2 spatial scales (within and among overwintering sites) in the eastern Pacific Flyway. Genome-wide analyses of 874 single nucleotide polymorphisms across 80 sampled individuals revealed no evidence for genetic differentiation among aggregations overwintering at 3 locations within the Fraser River Estuary (FRE) of British Columbia. Similarly, comparisons of aggregations in the FRE and those overwintering in southern sites in California and Mexico indicated no genetic segregation between northern and southern overwintering areas. These results suggest that Pacific Dunlin within the FRE, Sacramento Valley (California), and Guerrero Negro (Mexico) are genetically homogeneous, with no evident genetic structure between sampled sites or regions across the overwintering range. Despite no evidence for differentiation among aggregations, we identified a significant effect of geographical distance between sites on the distribution of individual genotypes in a redundancy analysis. A small proportion of the total genotypic variance (R2 =0.036, P = 0.011) was explained by the combined effect of latitude and longitude, suggesting weak genomic patterns of isolation-by-distance that are consistent with chain-like migratory connectivity between breeding and overwintering areas. Our study represents the first genome-scale investigation of population structure for a Dunlin subspecies and provides essential baseline estimates of genomic diversity and differentiation within the Pacific Dunlin.

Parameters of Kava Used as a Challenge to Alcohol

1986 ◽  
Vol 20 (1) ◽  
pp. 70-76 ◽  
Author(s):  
John Cawte
Keyword(s):  
Alcohol Abuse ◽  
Northern Territory ◽  
Clinical Effects ◽  
Pacific Island ◽  
Human Metabolism ◽  
Northern Australia ◽  
Surprising Effect ◽  
Greek Tradition ◽  
High Level

The kava bowl, a traditional feature of Pacific Island societies, has been adopted and adapted by a number of Aboriginal (Yolngu) communities of northern Australia, where it was introduced in the hope that it would challenge alcohol. This paper reports a study of its usage at Elcho Island, Northern Territory. At the high level of intake in this community, medical effects hitherto unreported are being observed. Some, such as a condition of detachment, reminiscent of the archetypal ‘blissful indolence’ of the lotus-eaters of Greek tradition as limned by the poet Homer, are obvious to the lay observer. Other effects are apparently advantageous for the management of alcohol abuse and some forms of psychosis. A surprising effect is the occurrence of a pellagrinous reaction. These observations indicate that further studies of the clinical effects and the human metabolism of high dosage kava are needed. Looming over all are questions of pharmacology. Do the kava pyrones possess anxiolytic or antipsychotic properties? Do they indeed have the property for which Pacific missionaries introduced them to Australia, as an alternative to alcoholism?

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