Growth, episodic recruitment and age truncation in populations of a catadromous percichthyid, Macquaria colonorum

2010 ◽  
Vol 61 (4) ◽  
pp. 397 ◽  
Author(s):  
Chris T. Walsh ◽  
Charles A. Gray ◽  
Ron J. West ◽  
Dylan E. van der Meulen ◽  
Lindsay F. G. Williams
Keyword(s):  
Habitat Degradation ◽  
Environmental Flows ◽  
Anthropogenic Impacts ◽  
Fish Length ◽  
Commercial Fishing ◽  
Marginal Increment ◽  
History Of ◽  
Young Of The Year ◽  
Three Rivers ◽  
Episodic Recruitment

Temperate basses and perches (family Percichthyidae) worldwide have declined in distribution and abundance during the past few decades due to anthropogenic impacts such as fishing, habitat degradation and alteration to river flows. This study examined differences in the age, growth and longevity of Macquaria colonorum among three south-eastern Australian coastal rivers. Estimates of ages were made by counting opaque zones in sectioned otoliths. Ages were validated by using marginal increment analysis, staining fish otoliths with oxytetracycline and sampling young-of-the-year fish. Length-at-age data from 1644 fish indicated that growth of M. colonorum is rapid in the first 3 to 4 years, after which it slows considerably. Females grew faster and reached larger asymptotic lengths than males. The species was found to be long lived, with the oldest fish estimated at 41 years. Population age structures indicated variable year-class strengths in all three rivers and there was an absence of larger, older (>10 years) individuals in the populations from the two rivers with a history of commercial fishing. These results indicate that M. colonorum populations, similar to other global percichthyid and estuarine-dependent fishes, have been subjected to episodic recruitment and age truncation and that these are likely influenced by environmental flows and fishing pressure.

scholarly journals Monitoring Skeletal Anomalies in Big-Scale Sand Smelt, Atherina boyeri, as a Potential Complementary Tool for Early Detection of Effects of Anthropic Pressure in Coastal Lagoons

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 159
Author(s):  
Chiara Leone ◽  
Francesca De Luca ◽  
Eleonora Ciccotti ◽  
Arianna Martini ◽  
Clara Boglione
Keyword(s):  
Early Detection ◽  
Habitat Degradation ◽  
Anthropogenic Impacts ◽  
Coastal Lagoons ◽  
Ecological Status ◽  
Detection Methods ◽  
Anthropogenic Pressures ◽  
Morphological Examination ◽  
Skeletal Anomalies

Mediterranean coastal lagoons are increasingly affected by several threats, all concurrently leading to habitat degradation and loss. Methods based on fish for the assessment of the ecological status are under implementation for the Water Framework Directive requirements, to assess the overall quality of coastal lagoons. Complementary tools based on the use of single fish species as biological indicators could be useful as early detection methods of anthropogenic impacts. The analysis of skeletal anomalies in the big-scale sand smelt, Atherina boyeri, from nine Mediterranean coastal lagoons in Italy was carried out. Along with the morphological examination of fish, the environmental status of the nine lagoons was evaluated using a method based on expert judgement, by selecting and quantifying several environmental descriptors of direct and indirect human pressures acting on lagoon ecosystems. The average individual anomaly load and the frequency of individuals with severe anomalies allow to discriminate big-scale sand smelt samples on the basis of the site and of its quality status. Furthermore, a relationship between skeletal anomalies and the environmental quality of specific lagoons, driven by the anthropogenic pressures acting on them, was found. These findings support the potentiality of skeletal anomalies monitoring in big-scale sand smelt as a tool for early detection of anthropogenic impacts in coastal lagoons of the Mediterranean region.

scholarly journals Urban manta rays: potential manta ray nursery habitat along a highly developed Florida coastline

2020 ◽  
Vol 43 ◽  
pp. 51-64 ◽  
Author(s):  
JH Pate ◽  
AD Marshall
Keyword(s):  
Anthropogenic Impacts ◽  
Life Stage ◽  
Nursery Habitat ◽  
Future Research ◽  
Separate Species ◽  
Western Atlantic ◽  
Photo Identification ◽  
History Of ◽  
High Site ◽  
Manta Ray

The giant oceanic manta ray Mobula birostris was listed in the US Endangered Species Act as a threatened species in 2018, yet insufficient data exist on manta populations throughout US waters to designate critical habitat. Taxonomic and genetic evidence suggests that manta rays in the Western Atlantic are a separate species (M. cf. birostris) and little is understood about the ecology and life history of this putative species. The juvenile life stage of both M. birostris and M. cf. birostris is particularly understudied. Here, we are the first to describe the characteristics of a manta ray population along a highly developed coastline in southeastern Florida using boat-based surveys and photo identification of individuals. Fifty-nine manta individuals were identified between 2016 and 2019. All males were sexually immature based on clasper development, and 96% of females were classified as immature based on size and absence of mating scars or visible pregnancies. Twenty-five (42%) individuals were observed more than once during the study period and 8 individuals were sighted over multiple years. The occurrence of juveniles, high site fidelity and extended use of the study area by juvenile manta rays suggest that southeastern Florida may serve as a nursery habitat. High occurrence of fishing line entanglement (27% of individuals) and vessel strike injury were documented, and rapid wound healing was observed. Future research and conservation efforts will focus on identifying the physical and biological features of the potential nursery habitat and on mitigation of anthropogenic impacts.

Freshwater, Fish and the Future: Proceedings of the Global Cross-Sectoral Conference

2016 ◽  
Keyword(s):  
Environmental Flows ◽  
Economic Valuation ◽  
Assessment Method ◽  
Fiscal Constraints ◽  
Use Of Data ◽  
Recreational Fishery ◽  
Murray Darling Basin ◽  
History Of ◽  
Harvest Data ◽  
Murray Cod

<em>Abstract</em> .—The collection and use of data to manage the freshwater fisheries of Australia’s Murray–Darling basin (MDB) has a poor history of success. While there was limited assessment data for early subsistence and commercial fisheries, even after more robust data became available during the 1950s its quality varied across jurisdictions and was often poorly collated, assessments were not completed, and the data were underutilized by management. The fishery for Murray Cod <em>Maccullochella peelii </em> is given as an example, where the fishery declined to the point of closure and then the decline continued to the extent that Murray Cod was listed as a threatened species and all harvest now only occurs through the recreational fishery. Lessons from such poor population assessments have not been fully learned, however, as there remains a paucity of harvest data for this recreational fishery. Without a proper assessment, a true economic valuation of this fishery has not been made. As the MDB is Australia’s food bowl, there are competing demands for water use by agriculture, and without a proper assessment of the worth of the fishery, it is difficult for Murray Cod to be truly considered in either economic or sociopolitical discussions. The poor state of MDB rivers and their fish populations (including Murray Cod) has, however, resulted in political pressure for the development of the sustainable rivers audit, a common assessment method for riverine environmental condition monitoring. This audit undertakes standardized sampling for fish and a range of other variables at a number of fixed and randomly selected sites on a 3-year rotating basis. While the sustainable rivers audit has provided a range of data indicating that the condition of rivers is generally very poor, these data have yet to be fully utilized to determine the potential state of the fisheries (such as Murray Cod) or to set targets for rehabilitation, such as for environmental flows. While, to date, data analyses have been somewhat restricted by fiscal constraints, more comprehensive use of data, together with full fishery valuations, should be seen as the way forward for improved management.

scholarly journals Long-term Annual Aerial Surveys of Submersed Aquatic Vegetation (SAV) Support Science, Management, and Restoration

2019 ◽  
Author(s):  
Robert J. Orth ◽  
William C. Dennison ◽  
Cassie Gurbisz ◽  
Michael Hannam ◽  
Jeni Keisman ◽  
...  
Keyword(s):  
Aquatic Vegetation ◽  
New Technologies ◽  
Anthropogenic Impacts ◽  
Monitoring Program ◽  
Commercial Fishing ◽  
Submersed Aquatic Vegetation ◽  
Essential Information ◽  
Aerial Surveys ◽  
The Impact

Abstract Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984–present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These examples demonstrate how periodically quantifying coverage of this important foundational habitat answers basic research questions locally, as well as globally, and provides essential information to resource managers. New technologies are enabling more frequent and accurate aerial surveys at greater spatial resolution and lower cost. These advances will support efforts to extend the applications described here to similar issues in other areas.

Global Offshore Hazardous Materials Sites GIS

2004 ◽  
Vol 38 (3) ◽  
pp. 36-43 ◽  
Author(s):  
John A. Lindsay ◽  
Robert Aguirre
Keyword(s):  
United States ◽  
Information System ◽  
Spatial Data ◽  
Hazardous Materials ◽  
The United States ◽  
Easy Access ◽  
Commercial Fishing ◽  
The Earth ◽  
History Of ◽  
Associated Data

Underwater dumpsites or hazardous material sites lie in every ocean on the earth. A geographic information system (GIS) project documents the locations and associated data of Global Offshore Hazardous Materials Sites (GOHMS) potentially posing threats to human health, safety, navigation, commercial fishing, and the environment. Nearly 350 sites are currently in the project. This paper discusses some of the history of hazardous materials disposal and loss at sea, primarily off the United States coast between 1945 and 1970 when few guidelines existed to geographically document an underwater site. Although not publicly distributed at present, the GOHMS GIS project is intended to add value to existing historical information by providing site investigators and responders easy access to waste stream locations and other spatial data through NOAA's Office of Response and Restoration and the National Marine Sanctuaries Program.

Challenge and response in the Indus Basin

Water Policy ◽  
2014 ◽  
Vol 16 (S1) ◽  
pp. 58-86 ◽  
Author(s):  
Madison Condon ◽  
Don Kriens ◽  
Anjali Lohani ◽  
Erum Sattar
Keyword(s):  
River Flow ◽  
Environmental Flows ◽  
Irrigation System ◽  
River System ◽  
Indus Basin ◽  
Implementation Challenges ◽  
History Of ◽  
Basin Irrigation ◽  
Indus Waters Treaty ◽  
Institutional Architecture

The authors examine the complex history of the development of the Indus Basin and the challenges faced by Pakistan during the evolution of the Indus Basin Irrigation System and the country's responses to date. The Indus river system must meet the multiple needs of agriculture, energy and flood security. Pakistan's constitutional structure, in which the federation shares overall responsibility for the operation of the Indus with the provinces, poses unique management and implementation challenges. What are the institutional arrangements Pakistan needs to address the challenges to the Indus Waters Treaty it signed with India in 1960? How is the country going to regulate the use of over-abstraction in the basin with the increased reliance on groundwater to maintain agricultural productivity? What are the institutional mechanisms in place to manage increased river flow variations from glacial melt as a result of climate change and for coping with devastating floods? At the same time, is the country maintaining adequate environmental flows to its delta? Provincial mistrust and a lack of institutional capacity underpins the history of the Indus in Pakistan with the Interprovincial Water Accord 1991 serving as a ray of hope on which to build a new institutional architecture of cooperation.

PARTING (WITH) THE DEAD: BODY PARTIBILITY AS EVIDENCE OF COMMONER ANCESTOR VENERATION

2012 ◽  
Vol 23 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Pamela L. Geller
Keyword(s):  
Social Class ◽  
Life Histories ◽  
Postmortem Changes ◽  
Body Parts ◽  
Ancestor Veneration ◽  
Social Settings ◽  
Three Rivers Region ◽  
The Reformation ◽  
History Of ◽  
Three Rivers

AbstractAs a complement to life histories authored by many researchers of Maya bones, this study narrates death histories. The latter entails detection of perimortem and postmortem changes to decedents' bodies, followed by translation of these changes' encoded meanings. Biographical analysis of body parts and the buildings in which they are situated facilitates such an endeavor. Past investigations of partibility have focused on protracted processing of noble and royal bodies as a means to reconstitute decedents' identities. Commoners' burials, however, have received far less attention. Consequently, it is difficult to determine if partible practices differ according to or transcend social class. To address this lacuna, a multiscalar frame is applied to a burial sample comprised of decedents from varied social settings in the Three Rivers region, northwestern Belize. Identification of widely shared practices related to the becoming and venerating of ancestors offers a springboard for examining particulars within patterns. Scaling down, commoner burials unearthed at the minor center RB-11 are summarized and special attention is paid to the death history of Individual 71. This decedent's intentionally fragmented body reflects general thinking about ancestors as partible and dividual persons. Yet, certain attributes of Individual 71's burial are unique to the sample as a whole, which demonstrates how social class, circumstance, and individual life history are also instrumental in the reformation of ancestorhood.

Australian waterbirds - time and space travellers in dynamic desert landscapes

2010 ◽  
Vol 61 (8) ◽  
pp. 875 ◽  
Author(s):  
R. T. Kingsford ◽  
D. A. Roshier ◽  
J. L. Porter
Keyword(s):  
Resource Availability ◽  
Environmental Flows ◽  
Anthropogenic Impacts ◽  
Aquatic Organisms ◽  
River Regulation ◽  
Population Declines ◽  
Time And Space ◽  
Regulated Rivers ◽  
Spatial And Temporal Scales ◽  
Resource Patches

Australia’s waterbirds are mostly nomadic, capitalising on highly variable aquatic resources in the arid interior (70% of the continent) for feeding and breeding. Waterbirds, unlike most aquatic organisms, can move between catchments, exploiting habitat wherever it occurs. In Australia, patterns of resource availability for waterbirds are mostly pulsed with peaks of productivity, coinciding with flooding and differing in time and space, affecting individuals, species and functional groups of waterbirds. Australian waterbirds are no different from waterbirds elsewhere, with their behaviour reflecting broad-scale resource availability. They respond to changing patterns of resource distribution, with rapid movements at spatial and temporal scales commensurate with the dynamics of the resource. The most serious conservation threat to waterbirds is a bottleneck in resource availability, leading to population declines, increasingly forced by anthropogenic impacts. River regulation and other threats (e.g. draining) reduce the availability of wetland habitat and decrease the probability of viable resource patches. It is axiomatic that waterbirds need water and such population bottlenecks may occur when the availability of water across the continent is limited. The rehabilitation of regulated rivers with environmental flows and protection of naturally flowing rivers in the arid region are essential for long-term sustainability of Australia’s waterbird populations.

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