Distribution and ontogenetic habitat shifts of reefassociated shark species in the northeastern Caribbean

Understanding how reef-associated sharks utilise coastal reef habitats throughout their ontogeny is essential for their effective management. In this study, we assessed the distribution of sharks in the northern Caribbean Netherlands (Saba, Saba Bank and St Eustatius) and ontogenetic shifts in habitat and depth use of the 2 most observed species: Caribbean reef shark Carcharhinus perezi and nurse shark Ginglymostoma cirratum. We used stereo baited remote underwater video (stereo-BRUV) surveys at 376 sites. A total of 126 shark sightings (6 species) were recorded, with C. perezi (n = 72) and G. cirratum (n = 42) most frequently observed. The probability of recording at least 1 shark per deployment ranged from 0.19 to 0.37 and is comparable with shark occurrences in the small number of other stereo-BRUV studies in the Wider Caribbean Region. Habitat type was the most important factor driving reef-associated shark occurrences, with the highest probability of observing C. perezi and G. cirratum in soft-coral habitat. Additionally, occurrences of C. perezi were significantly influenced by the management zone, with highest probabilities of occurrence in no-fishing zones. Almost all observed reef-associated sharks (95.6%) were juveniles, indicating that the study area may be a nursery area. Overall, both species were observed in deeper waters with increasing size, indicating ontogenetic shifts in depth use. Our findings imply that protected areas should not be limited to a single habitat or depth, but focus on protecting a large area with the range of habitats and depths necessary for reef-associated sharks to complete their life cycle.

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Temporal variation in the behaviour of a cooperatively breeding bird, Jungle Babbler (Argya striata) at diel and seasonal scale

10.1101/2021.11.06.467590 ◽

2021 ◽

Author(s):

Soniya Devi Yambem ◽

Manjari Jain

Keyword(s):

Habitat Type ◽

Group Living ◽

Ecological Factors ◽

Limited Resource ◽

Breeding Bird ◽

Individual Behaviour ◽

Time Activity ◽

Seasonal Scale ◽

Almost All ◽

The Impact

Time is an important and limited resource that can drive the trade-off between various essential activities in the lives of animals. Group-living animals need to perform different behaviour to meet their individual needs and also participate in group activities. They must, therefore, partition the available time between these activities which may vary considerably with environmental and ecological conditions. We examined time-activity budget of a cooperative passerine, Jungle Babbler (Argya striata) and how their behaviour vary across diel and seasonal scales. A repertoire of 13 behaviour was recorded of which 12 behaviour that occur throughout the year were examined further in detail. This included individual behaviour such as foraging, grooming, rest, shower and group behaviour such as allogrooming, movement, play, sentinel, mobbing and inter-group fight. Our results indicate that most of the time (about 70%) was spent performing individual behaviour and the remaining time (about 30%) was allocated to social behaviour. We also found almost all behaviour varied across diel and seasonal scale with respect to proportion of time spent performing them. This highlights the impact of environmental factors on how animals partition their time to perform various activities. Our study also lays the foundation for future studies examining the role of ecological factors such as habitat type and predation pressure in driving these patterns of behaviour in Jungle Babblers.

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New records of sharks (Elasmobranchii) from the Andaman and Nicobar Archipelago in India with notes on current checklists

Biodiversity Data Journal ◽

10.3897/bdj.6.e28593 ◽

2018 ◽

Vol 6 ◽

Cited By ~ 1

Author(s):

Zoya Tyabji ◽

Rima Jabado ◽

Dipani Sutaria

Keyword(s):

Geographical Location ◽

Shark Species ◽

Tiger Shark ◽

Limited Information ◽

Nurse Shark ◽

Important Species ◽

Inaccurate Information ◽

Management Measures ◽

Bull Shark ◽

Over Exploitation

The diversity of sharks occurring off the Andaman and Nicobar Archipelago in India has received increased attention in recent years. Yet, available checklists are out of date, often with inaccurate information and a number of commercially important species have not been documented through research and fish landing surveys. Here we report on shark species examined during fish landing surveys conducted from January 2017 to March 2018. Records of twelve previously unreported species from the archipelago are presented and include the bignose shark (Carcharhinusaltimus), pigeye shark (Carcharhinusamboinensis), bull shark (Carcharhinusleucas), snaggletooth shark (Hemipristiselongata), slender weasel shark (Paragaleusrandalli), Arabian smoothhound shark (Mustelusmosis), Indonesian houndshark (Hemitriakisindroyonoi), sand tiger shark (Carchariastaurus), Indonesian bambooshark (Chiloscylliumhasseltii), tawny nurse shark (Nebriusferrugineus), dwarf gulper shark (Centrophorusatromarginatus), and the Indonesian shortsnout spurdog (Squalushemipinnis). These records increase the reported shark species for the archipelago from 47 to 59 and for India from 114 to 116. Additionally, a size extension in the total length ofC.hasseltiiby 27 cm and ofP.randalliby 8 cm is reported. Owing to the bio-geographical location of these islands, species diversity around the archipelago is unique and appears to overlap with that of southeast Asia. With increasing reports of over-exploitation and the operation of a targeted shark fishery by distant water fleets in these waters, the limited information on shark diversity from this region is of concern. Systematic and long-term monitoring of catches, combined with accurate species identification, is crucial to provide information on management measures.

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Potential Distribution of Fall Armyworm in Africa and Beyond, Considering Climate Change and Irrigation Patterns

10.21203/rs.3.rs-196606/v1 ◽

2021 ◽

Author(s):

Bipana Paudel Timilsena ◽

Saliou Niassy ◽

Emily Kimathi ◽

Elfatih. M. Abdel-Rahman ◽

Irmgard Seidl-Adams ◽

...

Keyword(s):

Central Africa ◽

Fall Armyworm ◽

Large Area ◽

Western Africa ◽

The North ◽

Management Interventions ◽

Population Establishment ◽

Almost All ◽

North And South ◽

Irrigation Patterns

Abstract The fall armyworm, Spodoptera frugiperda (FAW), first invaded Africa in 2016 and has since become established in many areas across the continent where it poses a serious threat to food and nutrition security. We re-parameterized the existing CLIMEX model to assess the FAW global invasion threat, emphasizing the risk of transient and permanent population establishment in Africa under current and predicted future climates, considering irrigation patterns. FAW can establish itself in almost all countries in eastern and central Africa and a large part of western Africa under the current climate. Climatic barriers, such as heat and dry stresses, may limit the spread of FAW to North and South Africa. Future predictions suggest that FAW invasive range will retract from both northern and southern regions towards the equator. However, a large area in eastern and central Africa is predicted to have an optimal climate for FAW persistence. These areas will serve as FAW ‘hotspots’ from where it may migrate to the north and south during winter seasons and then pose an economic threat. Our projections can be used to identify countries at risk for permanent and transient FAW-population establishment and inform timely integrated pest management interventions under present and future climate in Africa.

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Life after death: behaviour of multiple shark species scavenging a whale carcass

Marine and Freshwater Research ◽

10.1071/mf18157 ◽

2019 ◽

Vol 70 (2) ◽

pp. 302 ◽

Cited By ~ 8

Author(s):

J. S. E. Lea ◽

R. Daly ◽

C. Leon ◽

C. A. K. Daly ◽

C. R. Clarke

Keyword(s):

Indian Ocean ◽

Western Indian Ocean ◽

Sperm Whale ◽

Shark Species ◽

Tiger Shark ◽

Nurse Shark ◽

Life After Death ◽

Galeocerdo Cuvier ◽

Carcharhinus Leucas ◽

Bull Shark

A drone was used to study the richness and behaviour of scavengers attracted to the carcass of a sperm whale (Physeter microcephalus) in Seychelles, Western Indian Ocean. Over 30 sharks of 3 species (tiger shark Galeocerdo cuvier, bull shark Carcharhinus leucas and tawny nurse shark Nebrius ferrugineus) were recorded scavenging on the carcass. Tiger sharks dominated the scavenging, but with no evidence of agonistic behaviours or hierarchy, and may have facilitated scavenging by other species. Drone use allowed the analysis of such behaviours without observer influence, providing new insights into communal scavenging events.

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Democratic transition in Guatemala: Toward a consolidated democracy or a failed state?

Estudios Latinoamericanos ◽

10.36447/estudios2012.v32.art3 ◽

2012 ◽

Vol 32 ◽

pp. 5-30

Author(s):

Karol Derwich

Keyword(s):

Latin American ◽

Democratic Transition ◽

Western Hemisphere ◽

Political Regime ◽

Caribbean Region ◽

Failed State ◽

Democratic System ◽

Democratic Systems ◽

Almost All ◽

Latin American And Caribbean

Since the late 1970s almost all Latin American and Caribbean countries have been experimenting with democracy. Some of them have succeeded in transitioning to a more democratic political regime, like Uruguay and Chile, while others are still trying to consolidate their democratic systems, such as Brazil and Mexico whereas others are encountering serious difficulties, like Bolivia and Ecuador. There are also states that have failed totally to build democratic systems, function confidently and accomplish basic assignments. In the most extreme cases, the failure of the democratization process has led to the total dysfunctioning of a state or even its collapse. The most significant example of this kind in the Western Hemisphere is Haiti. However, there are many more countries in the Latin American and Caribbean region that have serious problems with the proper adoption of democratic systems. This article is an attempt to analyze the problems with building a stable democratic system in Guatemala.

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A checklist of aquatic nematodes from Cuban Archipelago

Zootaxa ◽

10.11646/zootaxa.4731.3.1 ◽

2020 ◽

Vol 4731 (3) ◽

pp. 301-320

Author(s):

JOSÉ ANDRÉS PÉREZ-GARCÍA ◽

ALEXEI RUIZ-ABIERNO ◽

MAICKEL ARMENTEROS

Keyword(s):

Gulf Of Mexico ◽

Habitat Type ◽

Caribbean Sea ◽

Abundant Species ◽

Algal Turf ◽

Sampling Effort ◽

Large Area ◽

Free Living ◽

Seagrass Meadows ◽

Aquatic Nematodes

The diversity of free-living aquatic nematodes is largely unknown for the Gulf of Mexico and Caribbean Sea. The Cuban Archipelago is an important part of this because of its large area and diversity of habitats. We analyzed the free-living nematodes from 83 sites from seven aquatic habitats around Cuba, to produce a checklist for many habitats, including seagrass meadows, coral degradation zones, algal turf, bare sands, unvegetated muds, freshwater and anchihaline caves, and deep-sea sediments. The checklist contains 469 species, 229 genera, 50 families, and 9 orders. Chromadorida, Enoplida, and Monhysterida were the best represented orders with 112, 100, and 83 species respectively. The most abundant species were Euchromadora vulgaris, Terschellingia longicaudata, Desmodora pontica, Sabatieria pulchra , and Epsilonema sp. Most of the listed species were new records for the region. There were differences in the number of species recorded in each habitat type, with seagrass meadows having 280 species, coral degradation zones having 139 species, deep waters having 116 species, algal turf having 114 species, bare sands having 100 species, unvegetated muds having 78 species, freshwater caves having 19 species, anchihaline caves having 16 species, and freshwater streams having 6 species. The checklist is the most comprehensive recent report of the diversity of free-living nematodes in the regions of Gulf of Mexico and Caribbean Sea. The reported diversity is higher than many other regional checklists likely reflecting the intense sampling effort and the variety of microhabitats in Cuban Archipelago.

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Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States

Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States ◽

10.47886/9781888569810.ch22 ◽

2007 ◽

Keyword(s):

Gulf Of Mexico ◽

Yucatan Peninsula ◽

The United States ◽

Shark Species ◽

Nurse Shark ◽

Negaprion Brevirostris ◽

Carcharhinus Limbatus ◽

Yucatán Peninsula ◽

Gill Net ◽

Juvenile Sharks

Abstract.—Mexican coastal waters of the Gulf of Mexico serve as nursery areas for many shark species and traditional fishing grounds for artisanal fishermen. To characterize the use of these areas as shark nurseries, obtain information on the biology of juvenile sharks and understand the fishing pressure on these resources, a multiyear study was conducted in Laguna Yalahau, a shallow coastal lagoon located on the northeastern corner of the Yucatán Peninsula. Using primarily gill-net surveys and tagging of juvenile sharks during the late spring months of May–June, our binational research team conducted six expeditions inside the lagoon from 1995 to 2001. Sixty-seven species of teleosts, elasmobranchs, and other marine vertebrates consisting of 5,590 individuals were collected during the surveys. We captured 1,384 sharks of which 99% were neonate, young-of-the-year, or older juvenile blacktip sharks Carcharhinus limbatus, confirming that Laguna Yalahau is a primary nursery for that species. Other sharks collected were lemon shark Negaprion brevirostris, bonnethead Sphyrna tiburo, nurse shark Ginglymostoma cirratum, and Atlantic sharpnose shark Rhizoprionodon terraenovae. Using the Petersen method during 2000 and 2001, we estimated the sampled population size of newborn blacktip sharks in the lagoon to be 726 and 1,066, respectively, born to approximately 189 and 277 maternal females, respectively. Over the course of the study, 1,155 sharks were tagged and released. The recapture rate of tagged sharks by artisanal fishermen was 21.9%, more than five times the rate for similar sharks off the Florida coast, and all recaptures came from the coast of the Yucatán Peninsula. In light of this high recapture rate, it appears that Laguna Yalahau serves as a primary nursery for sharks that have been heavily exploited by Mexican artisanal fishermen.

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Morphometric measurements of newborn blue shark Prionace glauca (Linnaeus, 1758) and characteristics of its potential parturition areas in coastal waters of Montenegro (Southeastern Adriatic)

Acta Adriatica ◽

10.32582/aa.60.1.6 ◽

2019 ◽

Vol 60 (1) ◽

pp. 61-67

Author(s):

Ilija Ćetković ◽

Ana Pešić ◽

Aleksandar Joksimović ◽

Jovana Tomanić ◽

Stefan Ralević

Keyword(s):

Coastal Waters ◽

Adriatic Sea ◽

Gravid Female ◽

Fishing Gear ◽

Shark Species ◽

Morphometric Measurements ◽

Blue Shark ◽

The World ◽

Different Types ◽

Almost All

The blue shark belongs to the group of the most widespread pelagic sharks in the world. It inha-bits the pelagic zone of almost all warm and temperate seas and oceans. As it is one of the most abundant shark species, it is frequently caught in different types of fishing gear operated in the pela-gic zone. This study provides the first data on the reproduction of this species in Montenegrin waters (in the Southeastern Adriatic Sea). Six newborn blue sharks were found during our field excursions. For three of them, detailed morphometric measurements are presented. Alongside the newborns, a gravid female was also recorded. The data was collected in the period from April to October 2017. According to the published literature and the data presented in this paper, species reproduction is likely to be seasonal. A review of the areas where the specimens were recorded was carried out in order to infer if the adult females choose them specifically as their parturition grounds

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The Thermal Decomposition of Thorium Oxalate

Australian Journal of Chemistry ◽

10.1071/ch9510644 ◽

1951 ◽

Vol 4 (4) ◽

pp. 644 ◽

Cited By ~ 1

Author(s):

R Beckett ◽

ME Winfield

Keyword(s):

Electrical Conductivity ◽

Thermal Decomposition ◽

Weight Loss ◽

Weight Loss Curve ◽

Large Area ◽

Small Temperature ◽

X Ray ◽

Almost All ◽

Thorium Oxalate ◽

Composition Of Products

The thermal decomposition of hydrated thorium oxalate was followed by determining weight loss, change in electrical conductivity, and chemical composition of products. At temperatures below 200�C. the weight-loss curve indicated the existence of a tri- and a dihydrate and possibly a pentahydrate of thorium oxalate as stages m the dehydration. At higher temperatures dehydration was accompanied by loss of CO and CO2. Almost all the (C2O4)= decomposed sharply over a small temperature range near 300�C. Although some carbonate was formed, it did not exceed a concentration of 0.076 mole per mole of total thorium. According to chemical analysis the residue after heating at 350�C. was ThO2 with a trace of carbonate and water. X-ray analysis, however, showed it to be a mixture of ThO2, and a second substance whose identity is unknown. In the electron microscope the hydrated oxalate and the thoria produced from it were little different in appearance. Both appeared as relic crystals which were square prisms about l μ across and 0.2 μ thick, with a characteristic central aperture which exposed a large area of surface.

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Fish Habitat: Essential Fish Habitat and Rehabilitation

Fish Habitat: Essential Fish Habitat and Rehabilitation ◽

10.47886/9781888569124.ch15 ◽

1999 ◽

Keyword(s):

Shallow Water ◽

Large Scale ◽

Benthic Communities ◽

Fish Habitat ◽

Habitat Type ◽

Demersal Fish ◽

Sediment Type ◽

Essential Fish Habitat ◽

Shark Species ◽

Management Plans

Abstract.— Major amendments in 1996 to the Magnuson-Stevens Fishery Conservation and Management Act require fisheries managers to define “essential” fish habitat and address the impact of fishing gear in their management plans. However, before considering what might qualify as essential fish habitat, it is necessary to first understand the association between fish and their habitat. Some studies have already revealed subtle relationships between fishes and sediment type; however, this approach does not quantify habitat complexity. We undertook a large-scale survey of demersal fish populations and benthic communities in the southern North Sea and eastern English Channel. As in other studies, water depth was closely linked to the main dichotomy in assemblage composition. Flatfishes occurred in shallow water, whereas roundfishes and small shark species were found in deeper habitats. Within each of these two sample station groupings, the assemblages dichotomised further on the basis of habitat type and benthic faunal associations. Three further groupings were identified within the deepwater habitat. These groupings were characterized by the presence of rocks, broken shells, or a large biomass of sessile epibenthos. Small shark species were almost exclusive to habitats with shelly substrata. In contrast, the shallow-water habitats were topographically less complex with sessile epibenthos of a smaller biomass. Flatfishes that were visual predators were most closely associated with habitats with some sessile epibenthos, whereas sole Solea solea , which largely locate their prey using chemosensory cues, were more closely associated with the least complex habitat. Although these flatfish habitats are intensively fished by bottom trawls, the characteristic sessile epifauna are relatively fast growing and are probably able to withstand such disturbance. In contrast, the deepwater sessile communities had sessile epifauna of a greater biomass with some slow-growing species that would be more vulnerable to fishing disturbance. However, these habitats are seldom fished using invasive techniques.

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