1 |
Sperm whale diet in New ZealandGómez-Villota, Felipe Unknown Date (has links)
Stomach contents of 19 mature sperm whales, 18 males and one female, that stranded on New Zealand beaches between the mid 1990s and 2004 were examined, identified and measured. Three of the stomachs were empty. All other samples consisted almost entirely of cephalopod beaks. A total of 23,223 cephalopod beaks (10,647 upper and 12,576 lower), representing at least 36 species in 17 families were found in the remaining 16 stomachs. Non-cephalopod remains in the stomachs of sperm whales stranded in New Zealand included limited quantities of fish, salps, crustacean exoskeletons, a copepod, some wood and sand.The present investigation represents the most comprehensive study of the diet of sperm whales in New Zealand since the early 1960s. The results show that oceanic squid of the families Histioteuthidae, Cranchiidae, Onychoteuthidae and Octopoteuthidae are the most common remains found in the stomachs of sperm whales stranded on New Zealand beaches, with the families Onychoteuthidae, Histioteuthidae, Octopoteuthidae and Architeuthidae being the most important by estimated weight in whale diet, and the families Cranchiidae, Pholidoteuthidae and Ancistrocheiridae secondarily so.The beaks of three cephalopod species thought to be restricted to Antarctic waters (Kondakovia longimana, Mesonychoteuthis hamiltoni and Psychroteuthis glacialis) were found in 12 of the stomachs, suggesting these whales had recently migrated into New Zealand from more southern feeding grounds. The amount of local cephalopod beaks in the stomachs suggests some of the stranded sperm whales did not feed much within New Zealand waters in the days prior to stranding.The beaks of Taningia danae, Octopoteuthis megaptera, Octopoteuthis sp. 'Giant' and Lepidoteuthis grimaldii are illustrated and described. Oblique and lateral illustrations of the lower beaks are given, as well as sections of the rostrum, jaw angle, shoulder and lateral wall, to show the major identifying features for each of the species.Squid are an important component of food chains in the Southern Ocean and they act as both high-level predators and prey for apex predators. Therefore, seasonal fluctuations in their abundance must have cascading effects on the diets of apex predators. With increasing global fishing effort, and with cephalopods representing over 4% of the global annual catch, there are competing interests between the ocean's top teuthophagous predators and the fishing industry.Uncertainty of the effects fisheries have on the marine ecosystem has stimulated numerous research studies in recent years. However, despite the economic and ecological importance of cephalopods, there are few ecological studies on them or their significance in the trophic systems of the deep-sea and their life cycles and distribution patterns are only now beginning to be understood. Additional dietary studies that investigate the cephalopod composition and size-class structure in the diet of predators are needed to assess their importance in deepsea food webs, and the potential impact that deep-sea fisheries might have on associated and dependant species, namely apex oceanic predators.The results of this study provide the first significant insight into the diet of the sperm whale, one of the most important apex predators in New Zealand waters.
|
2 |
Sperm whale diet in New ZealandGómez-Villota, Felipe Unknown Date (has links)
Stomach contents of 19 mature sperm whales, 18 males and one female, that stranded on New Zealand beaches between the mid 1990s and 2004 were examined, identified and measured. Three of the stomachs were empty. All other samples consisted almost entirely of cephalopod beaks. A total of 23,223 cephalopod beaks (10,647 upper and 12,576 lower), representing at least 36 species in 17 families were found in the remaining 16 stomachs. Non-cephalopod remains in the stomachs of sperm whales stranded in New Zealand included limited quantities of fish, salps, crustacean exoskeletons, a copepod, some wood and sand.The present investigation represents the most comprehensive study of the diet of sperm whales in New Zealand since the early 1960s. The results show that oceanic squid of the families Histioteuthidae, Cranchiidae, Onychoteuthidae and Octopoteuthidae are the most common remains found in the stomachs of sperm whales stranded on New Zealand beaches, with the families Onychoteuthidae, Histioteuthidae, Octopoteuthidae and Architeuthidae being the most important by estimated weight in whale diet, and the families Cranchiidae, Pholidoteuthidae and Ancistrocheiridae secondarily so.The beaks of three cephalopod species thought to be restricted to Antarctic waters (Kondakovia longimana, Mesonychoteuthis hamiltoni and Psychroteuthis glacialis) were found in 12 of the stomachs, suggesting these whales had recently migrated into New Zealand from more southern feeding grounds. The amount of local cephalopod beaks in the stomachs suggests some of the stranded sperm whales did not feed much within New Zealand waters in the days prior to stranding.The beaks of Taningia danae, Octopoteuthis megaptera, Octopoteuthis sp. 'Giant' and Lepidoteuthis grimaldii are illustrated and described. Oblique and lateral illustrations of the lower beaks are given, as well as sections of the rostrum, jaw angle, shoulder and lateral wall, to show the major identifying features for each of the species.Squid are an important component of food chains in the Southern Ocean and they act as both high-level predators and prey for apex predators. Therefore, seasonal fluctuations in their abundance must have cascading effects on the diets of apex predators. With increasing global fishing effort, and with cephalopods representing over 4% of the global annual catch, there are competing interests between the ocean's top teuthophagous predators and the fishing industry.Uncertainty of the effects fisheries have on the marine ecosystem has stimulated numerous research studies in recent years. However, despite the economic and ecological importance of cephalopods, there are few ecological studies on them or their significance in the trophic systems of the deep-sea and their life cycles and distribution patterns are only now beginning to be understood. Additional dietary studies that investigate the cephalopod composition and size-class structure in the diet of predators are needed to assess their importance in deepsea food webs, and the potential impact that deep-sea fisheries might have on associated and dependant species, namely apex oceanic predators.The results of this study provide the first significant insight into the diet of the sperm whale, one of the most important apex predators in New Zealand waters.
|
3 |
Bats, insects and pecans: habitat use and ecosystem services of insectivorous bats in a pecan agroecosystem in central TexasBraun de Torrez, Elizabeth Claire 22 January 2016 (has links)
Comprehensive wildlife conservation strategies must include consideration of the agricultural matrix and its integration into the greater landscape. Bats are postulated to provide critical pest suppression services, but the effects of agricultural intensification on insectivorous bats are not clear. Few studies have thoroughly investigated the ecosystem services provided by bats due, in part, to limited understanding of species-specific habitat use in agricultural landscapes, difficulties in prey identification, and the challenge of quantifying the impact of bats on pest populations and crops. My dissertation integrates these components to describe ecological relationships between the insects and bats associated with a pecan agroecosystem in central Texas. Specifically, I focus on the predator-prey relationship between bats and the pecan nut casebearer moth (PNC), a devastating pest of pecans. I begin with a literature review of the ecosystem services of insectivorous bats and the data necessary to thoroughly evaluate these services. I then assess the potential factors influencing species composition and spatio-temporal distributions of bats within the pecan agroecosystem. My results demonstrate higher activity and diversity of bats within the pecan agroecosystem than in the surrounding landscape likely due to roosting opportunities, but species-specific and seasonal differences exist in the effects of management intensity. Next, I investigate direct interactions between bats and PNC by measuring prey consumption patterns. I found that five species of bats prey upon PNC moths during all three critical population peaks prior to insecticide application, but there is variability in consumption among species. Finally, I assess indirect interactions between bats and pecans, by evaluating the effect of bat predation risk on pecan damage by PNC larvae. A negative relationship between foraging activity by bats and both PNC moths and PNC larval damage to pecans provides evidence that bat predation has quantitative downstream effects. My results highlight the conservation value of the agricultural matrix for bats and the complexities of accurately documenting ecosystem services provided by free-ranging mobile organisms.
|
4 |
ANALYSIS OF DIETARY OVERLAP BETWEEN YELLOW PERCH (PERCA FLAVESCENS) AND ROUND GOBY (NEOGOBIUS MELANOSTOMUS) IN WESTERN LAKE ERIE THROUGH GUT AND STABLE ISOTOPE ANALYSESMarschner, Caroline A. 21 November 2003 (has links)
No description available.
|
5 |
Microscopic Sampling of Dentine and Bone Collagen: Development of Sampling Methods for Carbon and Nitrogen Isotope AnalysisCurtis, Mandi J. January 2021 (has links)
Sampling methods for dentine and bone collagen have been evolving for several
decades. Incremental dentine collagen sampling and bone collagen sampling
have been limited by the available technology throughout that time. As the
technology for isotope ratio mass spectrometry analysis improves, the sampling
methods should improve as well. This research focused on developing a new
incremental dentine collagen sampling method and bone collagen microsampling
method for stable isotope analysis. This research aimed to increase the
temporal resolution of incremental dentine collagen sampling and provided
sequential collagen sampling from bone collagen for stable carbon and nitrogen
isotope analysis while limiting the destructive nature of bioarchaeological
analysis. It was determined that the temporal resolution for incremental analysis
could be reduced to approximate three months, opposed to the nine months
found in other sampling methods. It was also determined that detailed isotopic
data could be obtained from bone collagen when sampling the microstructures.
The increased amount of isotopic data from the bone collagen was an
improvement on the commonly used bulk collagen sampling. This research can
be utilised to answer several of the questions that archaeologists have been
asking about past populations. Isotopic analysis using the methods developed in
the research can provide a more detailed observation of the diet and health of past populations.
In addition, the developed methods for bone and dentine collagen reduced the amount of tissue
subjected to destructive analysis.
|
6 |
The Foods And Crops Of The Muisca: A Dietary Reconstruction Of The Intermediate Chiefdoms Of Bogota (bacata) And Tunja (hunza), ColombiaGarcia, Jorge Luis 01 January 2012 (has links)
The Muisca people of the Eastern Cordillera of Colombia had an exceptionally complex diet, which is the result of specific subsistence strategies, environmental advantages, and social restrictions. The distinct varieties of microclimates, caused by the sharp elevations in this part of the Andes, allows for a great biodiversity of plants and animals that was accessible to the native population. The crops of domesticated and adopted plants of the Muisca include a wide variety of tubers, cereals, fruits, and leaves that are described in detail in this thesis. The Muisca used an agricultural method known as microverticality where the different thermic floors are utilized to grow an impressive variety of species at various elevations and climates. This group also domesticated the guinea pig, controlled deer populations and possibly practiced pisiculture, patterns that are also described in this text. Some of the foods of the Muisca were restricted to specific social groups, such as the consumption of deer and maize by the chiefly classes and the consumption of roots and tubers by the lower class, hence the complexity of their dietary practices. The utensils utilized in the preparation and processing of foods, including ceramics and stone tools were once of extreme importance in the evolution of the Muisca diet and form an important part of this research as well as the culinary methods that are described in the Spanish chronicles and by contemporary experts. The majority of food products utilized by the Muisca in antiquity are still part of the diet of contemporary Colombians and the current uses of these foods can allow us to understand how these products were used by this pre-Columbian society. On the other hand, knowledge of the practices used by the Muisca can facilitate the preservation of these foods in the modern diet and avoid the introduction and replacement of these foods by nonnative products, which can be less nutritious.
|
Page generated in 0.0652 seconds