Use of otoliths to estimate size at sexual maturity in fish

The viability of an alternative method for estimating the size at sexual maturity of females of Plagioscion squamosissimus (Perciformes, Sciaenidae) was analyzed. This methodology was used to evaluate the size at sexual maturity in crabs, but has not yet been used for this purpose in fishes. Separation of young and adult fishes by this method is accomplished by iterative adjustment of straight-line segments to the data for length of the otolith and length of the fish. The agreement with the estimate previously obtained by another technique and the possibility of calculating the variance indicates that in some cases, the method analyzed can be used successfully to estimate size at sexual maturity in fish. However, additional studies are necessary to detect possible biases in the method.

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A comparison of the allometric growth in Uca leptodactyla (Crustacea: Brachyura: Ocypodidae) from two subtropical estuaries

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315404009828h ◽

2004 ◽

Vol 84 (4) ◽

pp. 733-735 ◽

Cited By ~ 9

Author(s):

Rosana Carina Flores Cardoso ◽

Maria Lucia Negreiros-Fransozo

Keyword(s):

Growth Pattern ◽

Sexual Maturity ◽

Carapace Length ◽

Brazilian Coast ◽

Allometric Growth ◽

Size At Sexual Maturity ◽

Subtropical Estuaries ◽

Habitat Similarity

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

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Detecting Straight Line Segments Using a Triangular Neighborhood

Advances in Visual Computing - Lecture Notes in Computer Science ◽

10.1007/978-3-642-17277-9_33 ◽

2010 ◽

pp. 320-328 ◽

Cited By ~ 1

Author(s):

Shengzhi Du ◽

Chunling Tu ◽

Barend Jacobus van Wyk

Keyword(s):

Line Segments ◽

Straight Line

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An Automatic Measurement Method for Absolute Depth of Objects in Two Monocular Images Based on SIFT Feature

10.20944/preprints201705.0028.v1 ◽

2017 ◽

Author(s):

Lixin He ◽

Jing Yang ◽

Bin Kong ◽

Can Wang

Keyword(s):

Automatic Measurement ◽

Depth Estimation ◽

Depth Information ◽

Scale Invariant ◽

Line Segments ◽

Sift Feature ◽

Novel Approach ◽

Straight Line ◽

Object Depth ◽

Scale Invariant Feature

It is one of very important and basic problem in compute vision field that recovering depth information of objects from two-dimensional images. In view of the shortcomings of existing methods of depth estimation, a novel approach based on SIFT (the Scale Invariant Feature Transform) is presented in this paper. The approach can estimate the depths of objects in two images which are captured by an un-calibrated ordinary monocular camera. In this approach, above all, the first image is captured. All of the camera parameters remain unchanged, and the second image is acquired after moving the camera a distance d along the optical axis. Then image segmentation and SIFT feature extraction are implemented on the two images separately, and objects in the images are matched. Lastly, an object depth can be computed by the lengths of a pair of straight line segments. In order to ensure that the best appropriate a pair of straight line segments are chose and reduce the computation, the theory of convex hull and the knowledge of triangle similarity are employed. The experimental results show our approach is effective and practical.

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Low-level Grouping of Straight Line Segments

Procedings of the British Machine Vision Conference 1991 ◽

10.5244/c.5.16 ◽

1991 ◽

Cited By ~ 19

Author(s):

A. Etemadi ◽

J. P. Schmidt ◽

G. Matas ◽

J. Illingworth ◽

J. Kittler

Keyword(s):

Line Segments ◽

Low Level ◽

Straight Line

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Seasonal variations in the population biology of Salmostoma bacaila (Cyprinidae) from a tributary of the Payra River, Bangladesh

Zoology and Ecology ◽

10.35513/21658005.2019.2.7 ◽

2019 ◽

pp. 113-119

Author(s):

Ahamed Ahamed ◽

Faruque Ahmed Zoarder ◽

Jun Ohtomi

Keyword(s):

Sex Ratio ◽

Seasonal Variations ◽

Population Biology ◽

Sexual Maturity ◽

Condition Factor ◽

Gonadosomatic Index ◽

Spawning Season ◽

Frequency Distributions ◽

Size At Sexual Maturity ◽

Management And Conservation

Some biological parameters of Salmostoma bacaila – including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor – were studied. Samples were collected seasonally during June 2017 to May 2018 from a tributary of the Payra River. The overall sex ratio was significantly different from the expected value of 1:1 (p < 0.001), in favour of male specimens. Females were significantly larger than males. Size at sexual maturity was estimated at 7.6~7.7 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate that the main spawning season is from spring to summer. The LWRs showed negative allometric growth in both sexes, but with clear seasonal variation. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The fin¬dings of this study will be helpful for management and conservation of S. bacaila populations.

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Minimum Cell Connection in Line Segment Arrangements

International Journal of Computational Geometry & Applications ◽

10.1142/s0218195917500017 ◽

2017 ◽

Vol 27 (03) ◽

pp. 159-176

Author(s):

Helmut Alt ◽

Sergio Cabello ◽

Panos Giannopoulos ◽

Christian Knauer

Keyword(s):

Linear Time ◽

Optimal Solution ◽

Time Algorithm ◽

Linear Time Algorithm ◽

Constant Number ◽

Line Segments ◽

Straight Line ◽

Minimum Number ◽

Number Of Segments ◽

Connection Problems

We study the complexity of the following cell connection problems in segment arrangements. Given a set of straight-line segments in the plane and two points [Formula: see text] and [Formula: see text] in different cells of the induced arrangement: [(i)] compute the minimum number of segments one needs to remove so that there is a path connecting [Formula: see text] to [Formula: see text] that does not intersect any of the remaining segments; [(ii)] compute the minimum number of segments one needs to remove so that the arrangement induced by the remaining segments has a single cell. We show that problems (i) and (ii) are NP-hard and discuss some special, tractable cases. Most notably, we provide a near-linear-time algorithm for a variant of problem (i) where the path connecting [Formula: see text] to [Formula: see text] must stay inside a given polygon [Formula: see text] with a constant number of holes, the segments are contained in [Formula: see text], and the endpoints of the segments are on the boundary of [Formula: see text]. The approach for this latter result uses homotopy of paths to group the segments into clusters with the property that either all segments in a cluster or none participate in an optimal solution.

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Chamelea gallina reproductive biology and Minimum Conservation Reference Size: implications for fishery management in the Adriatic Sea

BMC Zoology ◽

10.1186/s40850-021-00096-4 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Giada Bargione ◽

Fortunata Donato ◽

Giulio Barone ◽

Massimo Virgili ◽

Pierluigi Penna ◽

...

Keyword(s):

Sexual Maturity ◽

Adriatic Sea ◽

Seawater Temperature ◽

Reproductive Capacity ◽

Great Effort ◽

Important Species ◽

Spawning Period ◽

The Past ◽

Chamelea Gallina ◽

Size At Sexual Maturity

Abstract Background The striped venus clam Chamelea gallina is an economically important species in Adriatic Sea fisheries. The use of hydraulic dredging for its catch has a long history in Italy and its management faced several stages of development in the last 40 years. A great effort has been made in the past two decades to move from poorly or weakly managed fisheries to a well-structured co-management system to improve the sustainability of this fishery. However, a prerequisite for appropriate resource management is a sound knowledge of the biology and reproductive strategy of the species. Results We investigated three major biological features– the gametogenic cycle, size at sexual maturity and partial fecundity – by microscopic, histological and video analysis techniques. We demonstrated that its breeding season is driven by rises in seawater temperature and chlorophyll-a concentration and that its spawning period lasted from March to September. Size at sexual maturity was reached very early in the life cycle. As regards partial fecundity – the number of mature oocytes potentially released by females with ripe gonads in a single release event – varied in relation to size. Nevertheless, the reduction on the Minimum Conservation Reference Size (MCRS) from 25 to 22 mm (Delegated Regulation (EU) 2020/2237) lead to a 40% reduction in the number of emitted eggs. Conclusions We suggest that the ability of Adriatic clam stocks to withstand the strong fishing pressure of the past 40 years and the present one is due to their high reproductive potential and multiple spawning events combined with the effect of management measures (closed areas/seasons, quota, MCRS) and technical constraints on the gear and the sieve on board. Moreover, since the reduced MCRS for Venus shells is still larger than the size at maturity, it will probably not be detrimental to the reproductive capacity of the stock.

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Mapping with Monocular Vision in Two Dimensions

International Journal of Natural Computing Research ◽

10.4018/jncr.2010100106 ◽

2010 ◽

Vol 1 (4) ◽

pp. 56-65 ◽

Cited By ~ 1

Author(s):

Nicolau Leal Werneck ◽

Anna Helena Reali Costa

Keyword(s):

Optical Axis ◽

Two Dimensions ◽

Obstacle Detection ◽

Uniform Motion ◽

Mapping Algorithms ◽

Multiple Images ◽

Line Segments ◽

Straight Line ◽

Camera Intrinsic Parameters ◽

Over Time

This article presents the problem of building bi-dimensional maps of environments when the sensor available is a camera used to detect edges crossing a single line of pixels and motion is restricted to a straight line along the optical axis. The position over time must be provided or assumed. Mapping algorithms for these conditions can be built with the landmark parameters estimated from sets of matched detection from multiple images. This article shows how maps that are correctly up to scale can be built without knowledge of the camera intrinsic parameters or speed during uniform motion, and how performing an inverse parameterization of the image coordinates turns the mapping problem into the fitting of line segments to a group of points. The resulting technique is a simplified form of visual SLAM that can be better suited for applications such as obstacle detection in mobile robots.

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