Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals

<em>Abstract.</em> —Long-lived marine species are particularly vulnerable to human perturbations for reasons related both to the species’ demographics and human perception. Marine turtles provide an illustrative example: species delay maturity from 10 to as late as 30–60 years, and human monitoring of turtle populations focuses primarily on nesting adult females and nest production. Apparently marine turtles are trading early reproduction for later reproduction at a larger size, facilitating higher fecundity to overcome variable, often very high, natural mortality in eggs and early life stages. Human perturbations increase mortality of marine turtles at all life stages. However, population modeling has shown that annual survival of some stages, particularly large juveniles and adults, may be particularly critical to population maintenance and recovery. At the same time, monitoring focused on the larger, usually older, life stages of long-lived marine species may be a relatively poor indicator of actual population health and trends. High bycatch of long-lived marine species in long-line fisheries is outlined and concerns raised. Precautions, based on long-lived species’ vulnerability and the limitations of our ability to adequately monitor population status, should be built into management regimes.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam G. Clause ◽  
Aaron J. Celestian ◽  
Gregory B. Pauly

AbstractPlastic pollution, and especially plastic ingestion by animals, is a serious global issue. This problem is well documented in marine systems, but it is relatively understudied in freshwater systems. For turtles, it is unknown how plastic ingestion compares between marine and non-marine species. We review the relevant turtle dietary literature, and find that plastic ingestion is reported for all 7 marine turtle species, but only 5 of 352 non-marine turtle species. In the last 10 years, despite marine turtles representing just 2% of all turtle species, almost 50% of relevant turtle dietary studies involved only marine turtles. These results suggest that the potential threat of plastic ingestion is poorly studied in non-marine turtles. We also examine plastic ingestion frequency in a freshwater turtle population, finding that 7.7% of 65 turtles had ingested plastic. However, plastic-resembling organic material would have inflated our frequency results up to 40% higher were it not for verification using Raman spectroscopy. Additionally, we showcase how non-native turtles can be used as a proxy for understanding the potential for plastic ingestion by co-occurring native turtles of conservation concern. We conclude with recommendations for how scientists studying non-marine turtles can improve the implementation, quality, and discoverability of plastic ingestion research.


2003 ◽  
Vol 18 (2) ◽  
pp. 215-240

AbstractThis article explains the provisions of the Convention for the Conservation of Migratory Species of Wild Animals (CMS) and its subsidiary marine wildlife instruments as they relate to bycatch management. The CMS was primarily developed with the purpose of protecting and conserving migratory species and their habitats. The Convention was initially regarded as little more than a paper accord. Since its inception the CMS has undergone gradual significant changes not only in its scope but also in its geographical coverage. There are ten subsidiary instruments currently in force under the CMS which include regional accords on a wide range of marine species such as cetaceans, marine turtles and pinnipeds. These agreements have considerable potential for regulating the incidental capture of marine wildlife in fisheries. Issues of interest in regard to these agreements include the use of non-binding instruments, and mechanisms for coordination between accords. This article examines the CMS and its subsidiary instruments; it identifies challenges facing the Convention, and provides options for the development of more comprehensive approaches to the management of bycatch.


2021 ◽  
Author(s):  
Sathishkumar Pragasam

Abstract The impact of artificial lighting on birds and animals has been a subject of research for many decades. These studies have established that light pollution from offshore facilities result in disturbing effects on migratory birds and marine animals. It is understood from the various studies that light emanating from offshore structures attract birds at night and disorient them during their migratory flight. As they are distracted from their flight path, they are either found trapped by the light that they keep circling around the installations or make them to take shelter in the installations, ultimately making them miss their migratory journey. This results in reduced winter survival and reduced reproduction success. Many birds are also found to die eventually because of bird strike or by getting themselves incinerated in flares. Congregation of birds in offshore installations also lead to risks related to helicopter landing / take-off. It is also observed that artificial light attracts marine species like turtles and fishes, which result in adverse effects like alteration of feeding habits, impacted circadian rhythm and interference with their reproductive function. From the knowledge of aforementioned disruptive effects of artificial lighting, significant efforts have been made to develop lighting systems for offshore installations that are eco-friendly. Various means of mitigating the undesirable effects of artificial lighting in offshore installations are being tried in the last couple of decades.


Author(s):  
John S. Gray ◽  
Michael Elliott

As the oceans cover 70% of the earth’s surface, marine sediments constitute the second largest habitat on earth, after the ocean water column, and yet we still know more about the dark side of the moon than about the biota of this vast habitat. The primary aim of this book is to give an overview of the biota of marine sediments from an ecological perspective—we will talk of the benthos, literally the plants and animals at the bottom of the sea, but we will also use the term to include those organisms living on the intertidal sediments, the sands and muds of the shore. Given that most of that area is below the zone where light penetrates, the photic zone, the area is dominated by the animals and so we will concentrate on this component. Many of the early studies of marine sediments were taxonomic, describing new species. One of the pioneers was Carl von Linnaeus (1707–1778), the great Swedish biologist who developed the Linnaean classification system for organisms that is still used today (but under threat from some molecular biologists who argue that the Linnaean system is outdated and propose a new system called Phylocode). Linnaeus described hundreds of marine species, many of which come from marine sediments. The British marine biologist Edward Forbes was a pioneer who invented the dredge to sample marine animals that lived below the tidemarks. Forbes showed that there were fewer species as the sampled depth increased and believed that the great pressures at depths meant that no animals would be found deeper than 600 m. This was disproved by Michael Sars who in 1869 used a dredge to sample the benthos at 600 m depth off the Lofoten islands in Norway. Sars found 335 species and in fact was the first to show that the deep sea (off the continental shelf) had high numbers of species. Following these pioneering studies, one of the earliest systematic studies of marine sediments was the HMS Challenger expedition of 1872–1876, the first global expedition. The reports of the expedition were extensive but were mostly descriptive, relating to taxonomy and general natural history.


Science ◽  
2020 ◽  
Vol 369 (6499) ◽  
pp. 65-70 ◽  
Author(s):  
Flemming T. Dahlke ◽  
Sylke Wohlrab ◽  
Martin Butzin ◽  
Hans-Otto Pörtner

Species’ vulnerability to climate change depends on the most temperature-sensitive life stages, but for major animal groups such as fish, life cycle bottlenecks are often not clearly defined. We used observational, experimental, and phylogenetic data to assess stage-specific thermal tolerance metrics for 694 marine and freshwater fish species from all climate zones. Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming. The sequence of stage-specific thermal tolerance corresponds with the oxygen-limitation hypothesis, suggesting a mechanistic link between ontogenetic changes in cardiorespiratory (aerobic) capacity and tolerance to temperature extremes. A logarithmic inverse correlation between the temperature dependence of physiological rates (development and oxygen consumption) and thermal tolerance range is proposed to reflect a fundamental, energetic trade-off in thermal adaptation. Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish. By 2100, depending on the Shared Socioeconomic Pathway (SSP) scenario followed, the percentages of species potentially affected by water temperatures exceeding their tolerance limit for reproduction range from ~10% (SSP 1–1.9) to ~60% (SSP 5–8.5). Efforts to meet ambitious climate targets (SSP 1–1.9) could therefore benefit many fish species and people who depend on healthy fish stocks.


2016 ◽  
Vol 22 (2) ◽  
pp. 101-112
Author(s):  
Dalytė Matulevičiūtė

Abstract Several species of willowherb (Epilobium) are considered as agricultural weeds and their prevalence has become an increasing problem in agriculture. The aim of this study was to investigate the role of willowherb plants in the initial stage of vegetation succession a year after the use of glyphosate. The study was based on the examination of thirteen willowherb specimens collected in the apple orchard of 0.2 ha area in August 2008, one month after glyphosate treatment, and vegetation field investigations in the same orchard in July 2009. The coverage of herb layer, the abundance and life stages of Epilobium plants in twenty plots of 1 m2 in size were investigated. The specimens of willowherbs, which survived the glyphosate application in 2008, were identified as Epilobium ciliatum and E. tetragonum. A year after the glyphosate treatment, the willowherb plants prevailed in the vegetation. One alien (E. ciliatum) and three native (E. hirsutum, E. parviflorum and E. tetragonum) species of willowherb were found. E. ciliatum was the most abundant. This species was characterized by the highest number of reproductive and virginile plants. E. parviflorum and E. tetragonum plants were abundant with a very high proportion of reproductive plants. Only pre-reproductive plants of E. hirsutum occurred in the study plots. The reproductive plants represented more than one third of the total number of willowherb plants. The distribution patterns of willowherb species in the plots were very variable.


2020 ◽  
Vol 8 (3) ◽  
pp. 208 ◽  
Author(s):  
Agusti Torres ◽  
Ana-Maria Abril ◽  
Eric E. G. Clua

Baited remote underwater video systems (BRUVs) are efficient devices for remotely characterising the assemblage and relative density of fishes and other marine organisms. However, technological constraints (e.g., battery life and limited storage memory) typically limit deployment times to <2 h making it very difficult to capture the presence of marine species, including rare and elusive ones. We developed an extended duration (24 h) BRUV to enable fisheries-independent surveying of a pelagic shark population in the western Mediterranean. Video data revealed seven visits (three nocturnal, four diurnal) by blue sharks (Prionace glauca) over a period of 1355 h. In the future, this cost-effective device could be fitted with a wireless video transmitter to provide real-time observations of marine animals for scientific or ecotourism purposes.


Author(s):  
Michael W. Shafer ◽  
Eric Morgan

Bio-logging devices are systems mounted to an animal that measure parameters associated with the animal or its environment. These devices date back to the 1930’s in their simplest form, while modern devices use suites of digital sensors, microcontrollers, and wireless data communication. Despite these advances, there has always been a fundamental relationship between power consumption and the amount of science that can be conducted. There are now a number of commercially available devices that use solar cells to supplement their daily energy budget, but supplemental solar power is not useful for species that are nocturnal, subterranean, aquatic, or spend significant time beneath dense forest canopies. As such, there have been calls from the marine biology community for devices that could harvest power from their environments. For these marine species, alternative energy harvesting techniques are required. Here we explore a new application for energy harvesting as a power source for marine wildlife bio-logging tags. Marine animals cover wide swaths of the ocean, making tracking and data collection challenging. Tagging these animals with devices that track their location and/or collect data about the animal or its surroundings require large batteries and have limited life spans due to high power requirements for satellite data relays. With limited solar irradiance at depth making solar power less attractive, we review and explore other forms of energy that could be harvested, such as energy from fluid flow and hydrostatic pressure cycles. We investigate the energy potential from a number of sources and compare these values with the requirements of current bio-logging systems to assess required transduction efficiencies. The application of energy harvesting on animal tags could result in nearly indefinite life systems allowing for data collection from a single animal over the course of many years.


2016 ◽  
Vol 113 (42) ◽  
pp. E6325-E6334 ◽  
Author(s):  
Steven M. Stanley

Procedures introduced here make it possible, first, to show that background (piecemeal) extinction is recorded throughout geologic stages and substages (not all extinction has occurred suddenly at the ends of such intervals); second, to separate out background extinction from mass extinction for a major crisis in earth history; and third, to correct for clustering of extinctions when using the rarefaction method to estimate the percentage of species lost in a mass extinction. Also presented here is a method for estimating the magnitude of the Signor–Lipps effect, which is the incorrect assignment of extinctions that occurred during a crisis to an interval preceding the crisis because of the incompleteness of the fossil record. Estimates for the magnitudes of mass extinctions presented here are in most cases lower than those previously published. They indicate that only ∼81% of marine species died out in the great terminal Permian crisis, whereas levels of 90–96% have frequently been quoted in the literature. Calculations of the latter numbers were incorrectly based on combined data for the Middle and Late Permian mass extinctions. About 90 orders and more than 220 families of marine animals survived the terminal Permian crisis, and they embodied an enormous amount of morphological, physiological, and ecological diversity. Life did not nearly disappear at the end of the Permian, as has often been claimed.


Author(s):  
Jaisakthi Seetharani Murugaiyan ◽  
Mirunalini Palaniappan ◽  
Thenmozhi Durairaj ◽  
Vigneshkumar Muthukumar

Marine species recognition is the process of identifying various species that help in population estimation and identifying the endangered types for taking further remedies and actions. The superior performance of deep learning for classification is due to the property of estimating millions of parameters that have to be extracted from many annotated datasets. However, many types of fish species are becoming extinct, which may reduce the number of samples. The unavailability of a large dataset is a significant hurdle for applying a deep neural network that can be overcome using transfer learning techniques. To overcome this problem, we propose a transfer learning technique using a pre-trained model that uses underwater fish images as input and applies a transfer learning technique to detect the fish species using a pre-trained Google Inception-v3 model. We have evaluated our proposed method on the Fish4knowledge(F4K) dataset and obtained an accuracy of 95.37%. The research would be helpful to identify fish existence and quantity for marine biologists to understand the underwater environment to encourage its preservation and study the behavior and interactions of marine animals.


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