Carnivores In Order Research Articles

The Ecological Roles of Medium and Small Carnivores in the Terrestrial Animal Community in Liancheng National Nature Reserve, China.

It is vitally important to understand the ecological roles of medium and small carnivores in the context of the massive decline in the number of large carnivores around the world. Based on a spatial association network of terrestrial birds and mammals, this study analyzed the ecological roles of medium and small carnivores in the community in Liancheng National Nature Reserve. From October 2019 to June 2020, we obtained 3559 independent detections of 20 terrestrial birds and mammals from 112 camera traps. There are seven species that are medium and small carnivores present in the study area, including red fox (Vulpes vulpes), leopard cat (Prionailurus bengalensis), Chinese mountain cat (Felis bieti), stone marten (Martes foina), Asian badger (Meles leucurus), Siberian weasel (Mustela sibirica) and mountain weasel (Mustela altaica). By calculating the Phi coefficient of all species pairs, a spatial association network composed of twelve species was constructed. We analyzed the characterization of spatial associations by the Shannon-Wiener index and Lambda statistic. The results showed that: (1) the status of the network reflects the changes of community composition and structure after the decline in large carnivores and other species; (2) with the exception of the Chinese mountain cat and stone marten, the other five medium and small carnivores were located in the network, which played an important role in the complexity of the network and the maintenance of the community; (3) the medium and small carnivores could not take the place of the large carnivores in order to control the population of herbivores, such as Siberian roe deer (Capreolus pygargus) and Himalayan marmot (Marmota himalayana). The results of this study provide guidance for determining the direction and focus of conservation efforts.

Hemoplasma infection in wild captive carnivores

ABSTRACT: Hemoplasmas are bacteria able to adhere themselves loosely to the plasma membrane of erythrocytes and may parasitize several species of mammals. There are three known species of hemoplasmas that parasitize domestic and wild cats: Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’. Dogs are infected by at least two species of hemoplasmas: ‘Candidatus Mycoplasma haematoparvum’ and Mycoplasma haemocanis. The hemoplasmoses are very important in veterinary clinics, either because of its worldwide distribution and severity of clinical signs, depending on parasite species and host immune competence, or due to its zoonotic potential and capability of infecting endangered species. This study set out to investigate which hemoplasmas species parasitize different captive wild carnivores in order to clarify the epidemiology of hemoplasmoses in wild animals. Furthermore, the research intended to characterize the hematological changes caused by different species of hemotropic mycoplasmas infection in order to establish their clinical importance to wild species and the capacity of these species to become a reservoir of studied agents. Samples of 33 wild felids and 18 wild canids were investigated using polymerase chain reaction (PCR) to detect hemoplasmas DNA and it was observed that the occurrence of infection in these species is 45.5% and 83.3%, respectively. Factors such as age, gender or anaemia are not more frequent in animals positive for the infection. Therefore, it is concluded that infection caused by hemoplasmas in wild carnivores has high prevalence, and either agent pathogenicity is low, or chronic stage is more frequent, resulting in a low rate of diagnosis.

106 Assessment of fecal near infrared reflectance spectroscopy to detect and monitor the reproductive status of endangered Amur and Snow leopard females

Feces from captive and wild carnivores can yield valuable information about an individuals’ physiological and reproductive status, diet, and ecology. Near infrared spectroscopy (NIRS) is a rapid, noninvasive, cost-efficient technique widely used in the agricultural, pharmaceutical, and chemical industries that has gained traction in diagnostic and ecological field applications for herbivore species, such as wild deer, antelope, and giant panda. The aim of this study was to test the transferability of NIRS to measuring reproductive status in feces from 2 endangered carnivore species, the Snow (Panthera uncia) and Amur (Panthera pardus orientalis) leopards. Fecal near infrared spectra analysed with multivariate statistics were used to generate prediction models for estrone-3-glucuronide (E1G) and progesterone (P4). In the E1G NIRS model, fecal samples (n=93) were obtained from 5 female leopards (3 Amur, 2 Snow) at 5 different zoo facilities, whereas for the P4 NIRS model fecal samples (n=51) from only 1 pregnant Amur leopard was available. The hormones were extracted with methanol and quantified by enzyme-linked immunosorbent assays (C. Munroe), where the sample range for E1G was 0.20-2.17 μg/g and the range for P4 was 0.06-61.89 μg/g. The near infrared spectra (350-2500nm) were acquired with an ASD FieldSpec®3 portable spectrometer (Malvern Panalytical, Malvern, UK), and the chemometric analysis was realised using the Unscrambler® X v.10.4 (CAMO Software AS, Oslo, Norway). Hormone reference values were log transformed before chemometric analysis to account for the heterogeneity of variance. Spectral pretreatment of standard normal variate was applied to the truncated wavelength range 700-240 0nm in order to remove interference from the visible region (350-700nm) due to individual diets that can confer colour variants that alter spectral signatures. Initial principal component analysis for the E1G and P4 datasets models showed >95% of the variation was explained by 4 factors, with no separation of principal component analysis scores between species or reproductive status. Quantitative prediction models using partial least-squares regression on selected wavelength ranges yielded a coefficient of determination for E1G and P4 of 0.10-0.04 and 0.35-0.19 for calibrations and validations, respectively. These near infrared models require further mathematical processing and consideration of sample variation due to diet complexity in carnivores in order to accurately assess hormone levels and monitor reproductive cycles in these species. This work was supported by USDA-ARS Biophotonics Initiative grant #58-6402-3-018.

Leishmania in wolves in northern Spain: A spreading zoonosis evidenced by wildlife sanitary surveillance

Leishmaniosis is, to date, considered the second most important emerging vector-borne protozoal disease in the world after malaria. The form of zoonotic visceral leishmaniosis found in the Mediterranean basin is caused by Leishmania infantum, and its life cycle includes the domestic dog and a phlebotomine sandfly vector. This complex epidemiological cycle and its high prevalence of subclinical infection, hinder the surveillance and control of L. infantum, and allows it to go unnoticed at the geographical endemicity limits of the parasite or in recently colonized areas. We, therefore, tested 102 wolves (Canis lupus) and 47 other wild carnivores in order to detect Leishmania DNA by means of PCR. Samples were collected from 2008 to 2014 in Asturias (northern Spain), a region considered non-endemic for the parasite. The results obtained provided valuable information regarding the prevalence of Leishmania in wild carnivores in Asturias and its geographic distribution in the region: an average prevalence of 33% for wolves and an overall prevalence of 40% for all the wild carnivores studied were reported, with a widespread presence of the parasite in the region and an apparent increase in its prevalence in wolves during the last decade. This suggests the usefulness of the wolf as a sentinel species for the detection and study of Leishmania in the field and confirms the value of wildlife sanitary surveillance programs for the detection and monitoring of hitherto disregarded diseases that affect domestic animals and humans.

Diagnóstico de la actividad pesquera artesanal en la Bahía de Tela

El siguiente artículo describe las características que presenta la pesca artesanal en la Bahía de Tela, esta actividad es una de las más significativas para las comunidades del área, no solo por las ventajas que implica realizar esta activad (independencia, nutrición y seguridad alimentaria) pero también, debido a la falta de alternativas económicas y empleo, la pesca es una fuente de ingreso permanente para los pescadores. El objetivo general fue el de elaborar herramientas de manejo y conservación pesquera para la Bahía de Tela (costa norte de Honduras), incluyendo el Refugio de Vida Silvestre Marino Bahía de Tela, Parque Nacional Punta Izopo y Parque Nacional Jeannette Kawas. Para el análisis de la situación socioeconómica de las comunidades pesqueras, se emplearon distintas metodologías como los siguientes: censos pesqueros y encuestas socioeconómicas, esto permitió conocer la problemática que enfrentan.Para los muestreos biológicos, se consideraron tres comunidades representativas del área: las comunidades garífunas de Tornabe, Miami y Tela. La toma de datos de los muestreos pesqueros abarca el periodo de tiempo comprendido desde febrero del 2015- abril del 2016. Con el fin de evaluar los recursos pesqueros se tomaron consideraciones ecológicas, dinámica de poblaciones y esfuerzo pesquero. La pesquería en Tela se encuentra en un estado crucial, ya que aún hay un porcentaje de especies que pertenecen a niveles altos en la cadena trófica; sin embargo si se sigue explotando insosteniblemente, aumentará la explotación de carnívoros de primer orden y luego herbívoros; afectando la salud del ecosistema y la pesquería.Revista Portal de la Ciencia, No. 12, junio 2017; 36-50

OVERVIEW OF THE EPIZOOTIC SITUATION ON RABIES FOR 2015 IN THE RUSSIAN FEDERATION

The area of rabies in the Russian Federation in recent years covered a large part of the regions of the country. The number of affected animals and the location of disadvantaged areas are permanently and significantly changing, but all of these variations in most cases occur for natural reasons, the study of which allows to understand better the mechanisms of development of the epidemic. The number annual of rabies outbreaks in our country is higher compare with other anthropozoonotic diseases. Rabies in Russian Federation was registered at stably high levels during 2015, with the epizootic process being more intensive at the administrative districts of Central, Privolzhski, and Southern Federal regions. The major rabies reservoir in Russia are wild canines, mostly foxes, raccoon dogs, arctic foxes, wolfs, jackals, corsac foxes. Creation a zonal immune protection around residential areas should be part of an oral vaccination program for wild carnivores in order to minimize the epidemiologic risks.

Regarding beasts and humans: A review of taphonomic works with living carnivores

Understanding how fossil assemblages were formed and which species modified the bones recovered in archaeological sites is no easy task. Nevertheless, during recent decades taphonomists have been working on the study of living carnivores in order to have a framework available for comparing fossil assemblages. In this paper we provide an overview of the results obtained from taphonomic work with living carnivores, the limitations of the results in relation to the variety of procedures implemented, and the application of the results obtained from the fossil record. The experimental conditions, i.e., wild versus captive carnivores, the prey size of the carcasses, etc., in large part determine the validity of the results obtained from taphonomic observations. For this reason we must be cautious when comparing the data with the fossil record. More studies on carnivores, especially on wild species, are necessary for us to increase our knowledge of the role of carnivores in the fossil record.

Diel Variations and Ecological Aspects in Fish Assemblages of a Sandy Beach in the Semi-Arid Region of Northeast Brazil.

ABSTRACT For the demersal fish that inhabit sandy beaches, the variation between day and night periods represents a determinant factor in their behavior, especially for species that live in shallow waters. This research aims at determining whether there are differences in the fish assemblage structure of the sandy beach of Sao Cristovao, RN, Brazil, between diurnal and nocturnal periods. Samplings were carried out in 2011, during spring high tide period, with an otter trawl net. Dissimilarity between diurnal and nocturnal fish assemblages was confirmed by PERMANOVA results. No statistical differences were observed for richness and diversity of fish assemblage between day and night periods. The first and third order carnivores were the significantly more representative trophic categories during night and day periods, respectively. Only four species presented significant differences regarding total length of fish between the periods. The demersal fish assemblage of Sao Cristovao beach presented variations in the density of individuals between day and night periods. Dissimilarities were also recorded in trophic categories and in total lengths of individuals; however this occurred as a result of the high density of some species. The low depth of the beach may prevent the establishment of larger size adult fish, thus becoming a favourable environment for juveniles and small-sized fish species.

The missing lynx — understanding hunters' opposition to large carnivores

Local opposition to large carnivores is a frequent source of conflict and a major obstacle for large carnivore conservation worldwide. The aim of our study is to understand hunters' reasons for opposing large carnivores, paying particular attention to the social dimension of the conflict. In an area where a vigorous conflict about lynx (Lynx lynx) exists without there actually being individuals of this species resident, we conducted group discussions with hunters, a group that includes many lynx opponents. Results were interpreted using the theories of social identity and psychological reactance. We found that, despite the absence of large carnivores, hunters' perceptions and reasoning resembled those present in areas with resident large carnivores. This underlines the significance of the social dimension. Results show that the hunters' position in the lynx conflict is shaped by past experiences with pro‐lynx groups (forestry and nature conservation). In this interaction, hunters see their social identity as being threatened which in turn leads to group discrimination and reactance processes — the latter possibly resulting in illegal shootings of lynx. Thus, hunters' opposition is not solely about the impacts of the lynx, but also about defending their social identity and withstanding impairment of their perceived freedoms by other interest groups. We argue that actively dealing with such group dynamics could serve as a missing link between large carnivore protection and conflict management. Future large carnivore management should focus more on shaping the quality of the interaction between the managers, advocates and opponents of large carnivores in order to overcome group‐conflict and reactance processes.

Is anthropogenic cougar mortality compensated by changes in natural mortality in Utah? Insight from long-term studies

Understanding the interplay between exploitation and natural mortality is essential to guiding sustainable conservation of wildlife. Exploitation of carnivores by humans has long been thought to result in compensatory reductions of natural mortality among survivors. If rates of human exploitation exceed natural mortality, however, such actions will ‘add’ to overall mortality and could imperil the sustainability of such actions. We applied competing risk analyses to ⩾16years of data for heavily harvested and semi-protected cougar populations in Utah to test the additive and compensatory mortality hypotheses, while accounting for parameter uncertainty. We additionally tested for presence of the two primary mechanisms by which compensatory mortality can arise: density dependence and individual heterogeneity in mortality risks. Despite an opportunity for compensation in the heavily harvested population, we could not reject the additive mortality hypothesis when uncertainty in parameter estimates was accounted for. In the semi-protected population, however, we detected evidence for partial compensation of increased anthropogenic exploitation via reductions in natural mortality. As may be common in carnivore studies, we found that ignoring uncertainty in estimates of cause-specific mortality systematically led to biased conclusions regarding additive and compensatory mortality hypotheses. Efforts should be made to address and minimize this uncertainty in demographic studies of carnivores in order to avoid flawed management recommendations. To attain the necessary sample sizes for making sound inference, this may require that the spatial extent of management units be extended for territorial species with large home-range requirements.

The earliest Acheulean technology at Atapuerca (Burgos, Spain): Oldest levels of the Galería site (GII Unit)

This work presents a study of the oldest Acheulean lithic assemblages from the Galería site, specifically the GIIa subunit, which has been dated to c. 503 ± 95 ka, and compares them with the subsequent subunit in the sequence, GIIb, dated to around 237–269 ka. The main goals of this study are to offer a detailed technological characterization of the earliest Acheulean presence in Atapuerca and to assess the elements determining the technological variability in a given site by studying the sequence, evaluating the concept of variability and defining the aspects which determine it. The Galería site does not display the features of a living space. It is a cave which was accessed by both humans and carnivores in order to obtain the animal biomass of the herbivores that had fallen down into the cave through a natural shaft. The archaeological record is therefore incomplete and fragmented, since it is the product of highly changeable occupational dynamics. In the lower Galería levels, we identified the development from an almost exclusive use of cobbles as blanks for knapping activities in the earliest periods to an increasing use of flakes. In terms of raw materials, the initially predominant use of Neogene chert and quartzite evolved towards a more balanced use of six raw materials. Furthermore, there was an increase in the size of the large tools. After comparing these two Acheulean assemblages, it is important to put them into context by taking into account a) the significance of cobbles and flakes as blanks; b) the significance of cleavers; and c) the use of raw materials such as quartzite, sandstone or chert. These aspects have traditionally been used to facilitate comparisons of the technologies used within the Iberian Peninsula, and comparisons between the Acheulean technology of the Iberian Peninsula and North Africa and the European (i.e. trans-Pyrenean) Acheulean technology.

Wildlife disease ecology in changing landscapes: Mesopredator release and toxoplasmosis

Changing ecosystem dynamics are increasing the threat of disease epidemics arising in wildlife populations. Several recent disease outbreaks have highlighted the critical need for understanding pathogen dynamics, including the role host densities play in disease transmission. In Australia, introduced feral cats are of immense concern because of the risk they pose to native wildlife through predation and competition. They are also the only known definitive host of the coccidian parasite, Toxoplasma gondii, the population-level impacts of which are unknown in any species. Australia's native wildlife have not evolved in the presence of cats or their parasites, and feral cats may be linked with several native mammal declines and extinctions. In Tasmania there is emerging evidence that feral cat populations are increasing following wide-ranging and extensive declines in the apex predator, the Tasmanian devil, from a consistently fatal transmissible cancer. We assess whether feral cat density is associated with the seroprevalence of T. gondii in native wildlife to determine whether an increasing population of feral cats may correspond to an increased level of risk to naive native intermediate hosts. We found evidence that seroprevalence of T. gondii in Tasmanian pademelons was lower in the north-west of Tasmania than in the north-east and central regions where cat density was higher. Also, samples obtained from road-killed animals had significantly higher seroprevalence of T. gondii than those from culled individuals, suggesting there may be behavioural differences associated with infection. In addition, seroprevalence in different trophic levels was assessed to determine whether position in the food-web influences exposure risk. Higher order carnivores had significantly higher seroprevalence than medium-sized browser species. The highest seroprevalence observed in an intermediate host was 71% in spotted-tailed quolls (Dasyurus maculatus), the largest mammalian mesopredator, in areas of low cat density. Mesopredator release of cats may be a significant issue for native species conservation, potentially affecting the population viability of many endangered species.

Composition and assemblage structure of demersal fish from São Cristóvão beach, Areia Branca, RN

Fish assemblages are an important element of sandy beaches, as they are fundamental for these ecosystems' balance of energy. Descriptions of the structure of fish assemblages in the sandy beaches of northeastern Brazil are scarce; this is especially true for the state of Rio Grande do Norte, which northern coast is poorly studied. This study aimed to identify the fish fauna of São Cristóvão Beach and to determine their assemblage structure. Three trawlings, considered as replicates, were undertaken monthly, in the same day, during 10 minutes each time, parallel to the coastal line, and in the direction of current, from February 2010 to January 2011. To describe the general pattern of the fish assemblage, the abundance, frequency and trophic categories of each species were estimated. On São Cristóvão Beach, 8894 individuals were captured, belonging to 58 species, 48 genera and 28 families. The most abundant and frequent species were Pomadasys corvinaeformis (Steindachner, 1868), Cathorops spixii (Agassiz, 1829), Stellifer rastrifer (Jordan, 1889), Pellona harroweri (Fowler, 1917), Stellifer stellifer (Bloch, 1790), Chirocentrodon bleekerianus (Poey, 1867), Larimus breviceps Cuvier, 1830, Menticirrhus americanus (Linnaeus, 1758)and Conodon nobilis (Linnaeus, 1758). The most abundant trophic category was first order carnivores. The ichthyofauna of São Cristóvão Beach is diversified and the most representative families match those observed in sandy beach ecosystems from other Brazilian regions. The results presented here reflect the basic knowledge necessary to conduct further research in the region.

Mouth Allometry and Feeding Habits of Some Mediterranean Fishes

Feeding habits, diet composition, and food consumption in fishes have been related to various morphological characteristics notably the mouth (e.g., Karpouzi and Stergiou 2003), gut length (Kapoor et al. 1975, Kramer and Bryant 1995, Karachle and Stergiou 2010) and tail (Palomares and Pauly 1989, 1998, Pauly 1994, Karachle 2008). In particular, mouth shape and position, dentition, branchial spines (in terms of structure and number) and distance between gill rakers, and pharyngeal bone structure are strongly connected to species’ feeding and diet composition (Al-Hussaini 1947, Verigina 1991, Wootton 1998, Boyle and Horn 2006). Mouth gape is considered as an important, yet restraining, factor for food selection, capture, handling, and consumption (Keast and Webb 1966, Kapoor et al. 1975, Wainwright and Richard 1995, Karpouzi and Stergiou 2003, Makrakis et al. 2008, Goatley and Bellwood 2009). As fish grow, they tend to prey upon a greater size range of food items, and the mean size of the prey consumed increases, a fact more evident in second order carnivores and apex predators (Scharf et al. 2000, 2009, Stergiou and Karpouzi 2002, Karpouzi and Stergiou 2003, Arim et al. 2010). Such an increase in prey-size consumed is generally attributed to both morphological (e.g., ontogenetic mouth size increase) and physiological factors (e.g., vision acuity, increasing swimming ability), that allow predators to consume larger prey (Keast and Webb 1966, Kaiser and Hughes 1993, Juanes 1994, Juanes and Conover 1994, Hart 1997, Wootton 1998, Fordham and Trippel 1999). Therefore, and especially in carnivorous fishes, mouth shape and size can be used for the explanation of interACTA ICHTHYOLOGICA ET PISCATORIA (2011) 41 (4): 265–275 DOI: 10.3750/AIP2011.41.4.02

Carnivores, biases and Bergmann's rule

Studies of Bergmann's rule may encompass a non-random subsample of extant homeotherms. We examined patterns of correlation between skull length and geographical latitude in 44 species of carnivores in order to test the validity of Bergmann's rule in the Carnivora. Results were then compared to those of other studies. Significant positive cor- relation between skull length and latitude was found in 50% of carnivore species, while significant negative corre- lation was found in only 11% of species. These results indicate that the occurrence of Bergmann's rule in the Carnivora is less frequent than earlier published data suggest. Publication bias is not detected in published data. Therefore, previous studies of geographical size variation might be biased in favour of species known to follow Berg- mann's rule. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81, 579-588.

Spatial and temporal shifts in stable isotope values of the bottom-dwelling shrimp Nauticaris marionis at the sub-Antarctic archipelago

Spatial and temporal dynamics of carbon and nitrogen stable isotope signatures of the bottom-dwelling caridean shrimp Nauticaris marionis were measured during April and May between 1984 and 2000 in the vicinity of Marion Island (the Prince Edward Islands, Southern Ocean). There was one trophic-level enrichment in bulk δ15N and δ13C signatures between small ( 20 mm) specimens of N. marionis, suggesting distinct trophic differentiation among major shrimp size groups. Both δ15N and δ13C values of N. marionis increased with the depth, reflecting changes in their diet. There were no clear temporal trends in bulk δ15N signatures of N. marionis. However, compound-specific δ15N measurements of amino acids indicated that N. marionis from the inter-island realm occupied the trophic level of second order carnivores, while similarly sized shrimps in the near-shore realm were at the trophic level of first order carnivores. Compound-specific measurements also identified a change in the source of inorganic nitrogen at the base of the food web between the inter-island and near-shore realms. In contrast to the bulk δ15N values, a significant shift in bulk δ13C values of N. marionis was observed between 1984 and more recent years. This temporal change appears to be linked to changes in the overall productivity of the Prince Edward Island inter-island system, which could be linked to global climate change.

Swallowing the bait: is recreational fishing in Australia ecologically sustainable?

Recreational fishing is a growing component of the total fishery harvest in many countries, but the impacts of this sector on aquatic resources are often ignored in the management of aquatic systems. Recreational fishing is open-access, and in many inshore regions, the recreational harvest exceeds the commercial harvest. The environmental impacts from recreational angling can be both ecologically significant and broad in scope and include: the removal of a considerable biomass of a wide variety of species; discarded by-catch; possible trophic cascades through the removal of higher order carnivores; impacts on habitat through bait harvesting; impacts of introduced and translocated species to support angling fisheries; direct impacts on sea-birds, marine mammals and reptiles; and angler generated pollution. Management, for several reasons, has largely ignored these environmental impacts from recreational fishing. Recreational fishing impacts are cumulative, whereas there is a tendency for consideration of impacts in isolation. Recreational fishing lobbyists have generally been successful in focusing public and political attention on other impacts such as commercial fishing, and recreational fishing has tended not to come under close scrutiny from conservation and environmental groups. Without changes to the monitoring and management of recreational fisheries that incorporate the broad ecological impacts from the activity, it may not be ecologically sustainable in the long term and Australia will not meet its international obligations of protecting aquatic biodiversity. The definition of property rights and appropriate measures to prevent or manage large scale marine restocking are two emerging issues that also need to be addressed.

The Chaetognatha Community of the Agulhas Current: Its Structure and Related Properties

An objective technique was used to identify and study related groups of chaetognath species from the Southwest Indian Ocean off the coast of the Republic of South Africa. Groups or community—type data agreed with, corroborated, and extended the scope of data on single species, multiple species and hydrographic conditions. The most representative groups were from the data of the N70V—nets which formed 3 groups. The 1st (or main) group was composed of 9 species and was distributed as a unit almost solely in the upper 200 meters of oceanic waters, and occurred in neritic waters only when > 1 to 2 species were absent. This agrees with and corroborates individual species data as each was, according to its distribution and abundance, a resident of the general ocean and each showed, except 3 species found predominantly in deeper waters, a positive correlation with the flow—pattern of the Agulhas current. The 2nd (or associate) group of 3 species was found 61% of the time at mixed—water stations, the best of these being located along a line where mixing between neritic waters and the Agulhas current was most likely to occur. Hydrographic data gave no indication of the latter. The 3rd group was made up of 1 oceanic— species which was distinctive by virtue of its vertical distribution; it was a mesoplanktonic beast, inhabiting water >200 m in depth. Species fecundity correlated quite well with each group and its distribution, in that neritic individuals of only one species of the 1st (main) group contained significantly more eggs than corresponding oceanic individuals whereas neritic individuals of all 3 species of the 2nd (associate) group contained significantly more eggs than corresponding oceanic individuals. This evidence suggests that the species of each group were reacting similarly to their environment and that fecundity is a suitable index to hydrographic conditions. Despite the close similarity of chaetognath species in regard to their habitats and niches considerable overlap existed among the species as a result of differences in their horizontal and vertical distributions, in their abundances, in their size relationships, in food diversity which apparently allows for some specialization in feeding but not in a rigid manner, and finally in structural aspects of the food chain itself as 2 of the larger species appeared to function as 2nd—order carnivores.