Using line transect sampling to detect cetaceans and floating litter during vessel survey in western Black Sea

2021 ◽  
Author(s):  
Romulus-Marian Paiu ◽  
Arda M. Tonay ◽  
Costin Timofte ◽  
Angelica Paiu ◽  
Mihaela Mirea Candea ◽  
...  
Keyword(s):  
Black Sea ◽  
Average Density ◽  
The Black Sea ◽  
Line Transect ◽  
Common Dolphin ◽  
Line Transect Sampling ◽  
Delphinus Delphis ◽  
Transect Sampling ◽  
Continuous Survey ◽  
Similar Density

<p>                The quality of the Black Sea ecosystem is partly but importantly dependent on the survival and sustainability of the top predator populations. It is difficult to foresee all consequences for the regional biodiversity if cetaceans disappear as it had happened with the Mediterranean monk seals in the past. During 7 days, between 30 September and 7 October, 2019, a joint oceanographical survey was made with a multipurpose R/V Mare Nigrum in offshore as well as deep sea locations, within the Romanian (RO), Bulgarian (BG) and western Turkish (TK) national waters of the Black Sea in the frame of ANEMONE project. The total track line was around 700 nautical miles and the sampled area covered 9754,58 km<sup>2</sup>. Observations were made of cetaceans and floating litter, following line transect sampling method, with a single platform (2 observers, on the left and right of the vessel bridge) over 380.44 km of transects. A total of 54 cetacean sightings and 81 floating litter items were recorded. All the three species, short-beaked common dolphin (<em>Delphinus delphis</em> ssp. <em>ponticus</em>), Black Sea bottlenose dolphin (<em>Tursiops truncatus</em> ssp. <em>ponticus</em>), and Black Sea harbour porpoise (<em>Phocoena phocoena </em>ssp. <em>relicta</em>), were registered with a similar density (individuals/km<sup>2</sup>), 0.012 for RO sector and 0.013 for BG-TK sector. The number of debris varied between 1 and 24 items, reaching 5.26± 5.93 items on average. Among the transects, 53% contained less than 5 items and only 13% were with more than 10 items. Based on these results, the average density of floating macro-litter in BG waters was found 2.43 ± 2.4 items/km<sup>2</sup>, 1.73 ± 1.24 items/km<sup>2 </sup>in the RO waters and 2.43±2.17 items/km<sup>2</sup> in TR waters. This study was the first to make a joint and continuous survey effort for both cetaceans and litter simultaneously in the Black Sea.</p><p><strong>Key words:</strong>  Black Sea, cetaceans, marine litter, joint cruise, ANEMONE project.</p>

scholarly journals Estimating a resource selection function with line transect sampling

2002 ◽  
Vol 6 (4) ◽  
pp. 213-228 ◽  
Author(s):  
Bryan F. J. Manly
Keyword(s):  
Resource Selection ◽  
Probability Function ◽  
Resource Selection Function ◽  
Line Transect ◽  
Selection Function ◽  
Line Transect Sampling ◽  
Selection Probability ◽  
Transect Sampling ◽  
Conditional Maximum ◽  
Habitat Variables

A resource selection probability function is a function that gives the prob- ability that a resource unit (e.g., a plot of land) that is described by a set of habitat variables X1 to Xp will be used by an animal or group of animals in a certain period of time. The estimation of a resource selection function is usually based on the comparison of a sample of resource units used by an animal with a sample of the resource units that were available for use, with both samples being assumed to be effectively randomly selected from the relevant populations. In this paper the possibility of using a modified sampling scheme is examined, with the used units obtained by line transect sampling. A logistic regression type of model is proposed, with estimation by conditional maximum likelihood. A simulation study indicates that the proposed method should be useful in practice.

Host use pattern and life history of Liopetrolisthes mitra, a crab associate of the black sea urchin Tetrapygus niger

2000 ◽  
Vol 80 (4) ◽  
pp. 639-645 ◽  
Author(s):  
J.A. Baeza ◽  
M. Thiel
Keyword(s):  
Sea Urchin ◽  
Black Sea ◽  
Sea Urchins ◽  
Austral Summer ◽  
Average Density ◽  
The Black Sea ◽  
Reproductive Pattern ◽  
Host Use ◽  
Austral Spring ◽  
Use Pattern

The porcellanid crab Liopetrolisthes mitra is a common associate of the black sea urchin, Tetrapygus niger in north central Chile. The host-use pattern, population dynamics and reproductive pattern of L. mitra on sea urchins were examined between January 1996 and February 1997. Each month, between 60 and 95 per cent of all collected urchins hosted crabs, with the highest frequency of cohabitation occurring during the austral summer (January to March). Group sizes of crabs on individual urchins ranged from 1 to 25 crabs per host. The average density of crabs on the urchins ranged from 2 to 5.5 crabs per host. Large urchins were inhabited by crabs more frequently than small urchins but urchin size had no effect on the number or size of crabs. The sex ratio of adult crabs was ˜1:1 during most months. Reproduction occurred throughout the year but was most intense during the austral spring and summer (October to March), when the highest percentage of ovigerous females were found. Similarly, recruitment of L. mitra occurred throughout the year but reached a peak during austral summer and early autumn (January to May). All life stages of L. mitra including recently settled megalopae and reproductive adults were found on urchins. Size–frequency analysis indicated that many crabs live >1.5 years. The results of this study confirm that the association between L. mitra and T. niger is strong and persists throughout the benthic life of the commensal crab.

scholarly journals KEPADATAN POPULASI MAMALIA DARAT KARNIVORA DI CAMP LEAKEY KAWASAN TAMAN NASIONAL TANJUNG PUTING, KALIMANTAN TENGAH

Jurnal BIOMA ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. 83
Author(s):  
Siwi Arthapati Mandiri ◽  
Paskal Sukandar ◽  
Yossa Istiadi
Keyword(s):  
Data Collection ◽  
Population Density ◽  
National Park ◽  
Line Transect ◽  
Line Transect Sampling ◽  
Clouded Leopard ◽  
Helarctos Malayanus ◽  
Transect Sampling ◽  
Palm Civet ◽  
Leopard Cat

Borneo has wide land that support high biodiversity. One of them is Tanjung Puting National Park (TPNP), which have biodiversity such as terrestrial mammalian carnivore. Carnivore has a role to maintain its ecosystems. But, there are no data for population density of terrestrial mammalian carnivore. The object of this research is to find out population density of terrestrial mammalian carnivore in Camp Leakey, TPNP, Central Borneo. This research accomplished in September-October 2015 in Camp Leakey. Using line-transect sampling. Data collection was accomplished at 18.00-24.00 Central Indonesian Time (WITA) on eight transects with three times replication by direct surveys and indirect surveys. This research has obtained five species, malayan sun bear (Helarctos malayanus), sunda clouded leopard (Neofelis diardi), leopard cat, and group of civet, like small-toothed palm civet (Arctogalidia trivirgata) and asian palm civet (Paradoxurus hermaphroditus). Population density of each species from the highest to the lowest is 13,5 Individual of leopard cat/km2, 9,84 Individual of malayan sun bears/km2, 4,31 Individual of sunda clouded leopard/km2, and 3,65 Individual of civet/km2. Malayan sun bears, sunda clouded leopards and civets prefer to be in land forest. Leopard cats prefers to be in transition forest.

scholarly journals Performance of Parametric Model for Line Transect Data

2020 ◽  
pp. 1-7
Author(s):  
Noryanti Muhammad ◽  
Gamil A.A. Saeed ◽  
Wan Nur Syahidah Wan Yusoff
Keyword(s):  
Simulation Study ◽  
Present Model ◽  
Parametric Model ◽  
Line Transect ◽  
Population Abundance ◽  
Line Transect Sampling ◽  
Detection Function ◽  
Transect Sampling ◽  
Proposed Model ◽  
Shoulder Condition

One of the most important sides of life is wildlife. There is growing research interest in monitoring wildlife. Line transect sampling is one of the techniques widely used for estimating the density of objects especially for animals and plants. In this research, a parametric estimator for estimation of the population abundance is developed. A new parametric model for perpendicular distances for detection function is utilised to develop the estimator. In this paper, the performance of the parametric model which was developed using a simulation study is presented. The detection function has non-increasing curve and a perfect probability at zero. Theoretically, the parametric model which has been developed is guar-anteed to satisfy the shoulder condition assumption. A simulation study is presented to validate the present model. Relative mean error (RME) and Relative Bias (RB) are used to compare the estimator with well-known existing estimators. The results of the simulation study are discussed, and the performance of the proposed model shows promising statistical properties which outperformed the existing models. Keywords: detection function, line transect data, parametric model

scholarly journals Double Kernel Method Using Line Transect Sampling

2016 ◽  
Vol 41 (2) ◽  
Author(s):  
Omar Eidous ◽  
M.K. Shakhatreh
Keyword(s):  
Kernel Method ◽  
Kernel Estimator ◽  
Real Data ◽  
Line Transect ◽  
Population Abundance ◽  
Line Transect Sampling ◽  
Numerical Examples ◽  
Bootstrap Techniques ◽  
Transect Sampling ◽  
Kernel Type

A double kernel method as an alternative to the classical kernel method is proposed to estimate the population abundance by using line transect sampling. The proposed method produces an estimator that is essentially a kernel type of estimator use the kernel estimator twice to improve the performances of the classical kernel estimator. The feasibility of using bootstrap techniques to estimate the bias and variance of the proposed estimator is also addressed. Some numerical examples based on simulated and real data are presented. The results show that the proposed estimator outperforms existingclassical kernel estimator in most considered cases.

Incidental by-catch of Delphinus delphis in the Black Sea

2019 ◽  
Vol 166 ◽  
pp. 145
Author(s):  
R.I. Rizac ◽  
A.C. Stoian ◽  
D.G. Soare ◽  
C. Gal ◽  
T. Soare
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Delphinus Delphis ◽  
By Catch
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