Comparing sampling strategies for surf-zone fish communities

2013 ◽  
Vol 64 (2) ◽  
pp. 102 ◽  
Author(s):  
Cassiano Monteiro-Neto ◽  
Luana Prestrelo

Beach seining is used for capturing surf-zone fishes for scientific or fishery purposes. Sampling gear and different sampling approaches pose difficulties for comparative analyses. We compared parallel tows (PT) and beach hauls (BH) using the same beach seine, observing differences in species number (SPUA = number of species m–2), total and relative abundance (CPUA = number of individuals m–2) and average size. ANOVA and PERMANOVA showed that both the number of species and abundance were significantly different between sampling approaches and seasons, with higher values for BH. Most abundant Umbrina coroides showed significant interactions with higher CPUA for PT in summer and Diplodus argenteus for BH from winter to summer. Harengula clupeola and Trachinotus carolinus showed significant differences between sampling strategy with BH capturing more individuals. Trachinotus carolinus and Sardinella brasiliensis both showed differences between seasons with higher CPUA in the summer and autumn respectively. Results suggest that catch structure and composition differ between sampling strategies, but a seasonal component associated with recruitment of one or more species also influenced the catch. The PT appears to be more effective but time consuming. The BH may be an alternative method, but results may not be comparable.

1987 ◽  
Vol 38 (5) ◽  
pp. 607
Author(s):  
AR Jones

Temporal patterns in number of species, number of individual animals and community composition of the soft-sediment zoobenthos of the Hawkesbury estuary are described and related to physicochemical factors. Replicate grabs were taken at 3-month intervals over 3 years (1977-1979) from sites located in three zones: the lower, middle and upper reaches. The number of species and number of individuals showed significant seasonal and annual differences in all zones. However, the pattern of these differences varied among sites and seasonal differences were not repeatable over years. Similarly, differences in community composition as revealed by classification were not seasonal. In the middle and lower reaches, these differences were apparently caused by the over- riding influence of non-seasonal climatic events, i.e. a major flood in 1978 and a drought throughout 1979. In the first two sampling following the flood, sample values for the numbers of both species and individuals were usually lowest and community composition was distinct from pre-flood and drought times. During the drought, the number of species was usually high and community composition relatively distinct. Whereas the number of species and community composition groupings were both significantly related to river discharge, the number of individuals was significantly correlated with temperature. All community variables were sometimes significantly related to salinity. The identity of numerically dominant species, as determined by Fager rankings, varied among times in both the lower and middle reaches. However, the polychaete Nephtys australiensis and the bivalve mollusc Notospisula trigonella were highest ranked overall in both zones. Community patterns in the low-salinity upper reaches differed from those further downstream by showing little change in numbers of species and community composition following the flood. Only the number of species was significantly correlated with any of the measured physicochemical variables, this being partly due to an influx of species during the drought. Furthermore, the upstream community was always dominated by the polychaete Ceratonereis limnetica and was thus the only community that could be characterised by a single species.


2021 ◽  
Vol 6 (2) ◽  
pp. 85
Author(s):  
Eka Yuliawati ◽  
Budi Afriyansyah ◽  
Nova Mujiono

<strong>Mangrove gastropod community in Perpat and Bunting Rivers, Belinyu District, Bangka Regency</strong>. Perpat and Bunting in Bangka Regency have an adequate and natural mangrove ecosystems. However, studies on the structure of the gastropod community in this ecosystem is lacking. This study aimed to discover the structure of the gastropod community in the mangrove ecosystem. This study was carried out from October to November 2019 in riverine mangrove area located in Perpat and Bunting Rivers, District Belinyu, Bangka Regency. Samples were taken from 10 x 10 m plot from six observed stations. A total of 578 individuals of gastropoda were collected, comprised of seven families and 14 species. Number of species ranged from 4 to 9, while number of individuals ranged from 35 to 214. <em>Cerithidea quoyii</em> was a dominant species with 270 individuals (47%) and found in all stations. Gastropods community was in labile condition and prone to environmental change. Species composition of gastropods were similar in both rivers with nine identical species. However, epifaunal species were found separately from arboreal species


2013 ◽  
Author(s):  
Xubin Pan

Sampling is a fundamental tool in ecology and critical for biodiversity measurement. However, basic principles of biodiversity sampling have been overlooked for many years. In this paper, I proposed and explored five principles of sampling for a specific area and biodiversity study. The first principle of sampling, species increasing with area, is that the number of species increases with the area. The second principle of sampling, individuals increasing with area, is that the number of individuals increases with the area. The third principle of sampling, sum of species number, is that the sum of species number in one area and species number in another area is no less than the total species number in the two areas. The fourth principle of sampling, individual complement, is that the sum of the mathematical expectation of individual number of one or several species in the area a and that of the same one or several species in the area A-a is the total individual number N of the same one or several species in the total area A. The fifth principle of sampling, species-area theory, is that the sum of the mathematical expectation of number of species in the area a and that of number of species lost if area A-a is cleared is the total species number M in the total area A.


1999 ◽  
Vol 59 (1) ◽  
pp. 43-53 ◽  
Author(s):  
M. APOLINÁRIO

The community structure in and around two barnacle (Chthamalus challengeri Hoek) patches (sites A and B) which extended from the middle to the upper intertidal zone on a pebbly shore in Magarisaki (Amakusa, Kyushu, Japan), was studied during summer and winter of 1995 and 1996. The results show a significant decrease in the proportion of substrate covered by barnacles from January 1995 to July 1996. The number of species, number of individuals, and biomass also decreased in the patch areas through time. There were significant differences between inside and outside the patches for percentage of substrate covered by barnacles, number of individuals, number of species, and biomass during the first year. Numbers of some gastropods were significantly higher in the barnacle patches, suggesting that the presence of barnacles create favorable microhabitat for the other taxa.


Author(s):  
Lina Budiarti ◽  
Jaenudin Kartahadimaja ◽  
Miranda Ferwita Sari ◽  
Destieka Ahyuni ◽  
Ni Siluh Putu Nuryanti, Dulbari

The abundance of predatory arthropods in the rice field ecosystem acts as a biological agent that suppresses pest populations. This study aims to analyze the types of species, individuals, and abundance of predatory arthropods. The research was conducted at the Lampung State Polytechnic Seed Teaching Farm in August-December 2020. The rice plant lines planted by Lampung State Polytechnic were 14 New Type Rice (PTB) lines, namely Pandan Wangi (PW, B1, B2, B3, B4, B7, D2, D3, F3, F4, H1, H4, K, and L2 with 2 and comparable superior varieties namely Ciherang (CH) and Gilirang (Gil)). Rice cultivation is carried out conventionally. Observations of predatory arthropods that inhabit rice canopy were carried out using 3 double swings of insect nets / sweepnets per treatment plot. Insect collection was carried out at 06.00-09.00 WIB then identified in the Food Crops Laboratory II, counting the number of species, number of individuals and relative abundance. The results showed that predatory arthropods that inhabit the canopy of rice plants in several rice plant lines were obtained from the Oxyopidae, Tetragnathidae, Lycosidae, Coenagrionidae, Correidae, Coccinellidae, Chrysomelidae, and Staphylinidae families. The Tetragnathidae and Coenagrionidae families have the highest proportion of species and are found in each rice plant line.


2016 ◽  
Vol 43 (2) ◽  
pp. 291-301
Author(s):  
Sultana Rajia ◽  
Md Mahabub Alam ◽  
Gawsia Wahidunnessa Chowdhury ◽  
Muntasir Akash ◽  
Md Anwarul Islam

A study on status and diversity of birds of Ramna Park, Dhaka, Bangladesh was conducted from July 2013 to March 2014. Data were collected through direct field observations where 6 days had been spent in every month in the field. A total of 50 species of birds belonging to 11 orders and 28 families were observed. Of the 50 species, 84% were residents and 16% migrants, 50% were passerines, 50% non-passerines. Passeriformes presented the highest number (25 species) of observed birds. Only Clamator jacobinus was recorded as summer migrant among the migratory birds. We found Psittacula eupatria considered as Near Threatened globally according to IUCN. Corvus splendens was the most common with the highest number of individuals in comparison to other bird species. We observed single individual of Clamator jacobinus followed by Psittacula eupatria and Apus pacificus throughout the study. Regarding the relative abundance, 18% species were very common, 30% common, 16% fairly common and 36% few. Calculating the Shannon-Wiener and Simpson’s indices of diversity and species evenness, we found maximum number of species and individuals in the month of December while minimum in the month of July. Anthropogenic activities such as festivals, random assemblies and gatherings, dumping of plastics, polythene and papers, noise from the vehicles were common inside and around the park, which may be threats to birds.Bangladesh J. Zool. 43(2): 291-301, 2015


1986 ◽  
Vol 37 (4) ◽  
pp. 521 ◽  
Author(s):  
AR Jones ◽  
CJ Watson-Russell ◽  
A Murray

Spatial patterns in the number of species, number of individual animals and community composition of the benthos of the Hawkesbury Estuary, N.S.W., are described and related to physicochemical factors. Replicate grabs were taken from deep and shallow sites located on transects across the estuary for each of five times at intervals of 3 months. The number of species and number of individuals always differed significantly along the estuary but the pattern of difference varied with both depth and time. Although a monotonic decline in the number of species along the estuary never occurred, the two most- seaward transects usually supported the most species and the three furthest-upstream transects the least. The number of species was usually more highly correlated with salinity than with sedimentary variables but salinity correlations were not always significant. The number of individuals was not related to any abiotic variable in a consistent way. Significant depth-related differences occurred only for the number of individuals although the pattern of difference varied among both transects and times. Sediment-associated differences also varied with transect and time. Where consistent differences occurred, highest species numbers were sometimes associated with sand and sometimes with coherent clay. Consequently the species-sediment relationship is not always a simple linear function of grain size and different aspects of sediment structure may be influential. Sediments with greater habitat heterogeneity sometimes supported more species and sometimes fewer species than more uniform sediments. Classification and ordination analyses revealed major patterns in community composition that were most closely related to salinity and minor patterns related to sediment grade. Community changes did not always correspond with physicochemical changes and hence the latter were not always good predictors of biological variables.


2017 ◽  
Vol 68 (7) ◽  
pp. 1391 ◽  
Author(s):  
D. Harasti ◽  
K. A. Lee ◽  
R. Laird ◽  
R. Bradford ◽  
B. Bruce

Stereo baited remote underwater video systems (stereo-BRUVs) are commonly used to assess fish assemblages and, more recently, to record the localised abundance and size of sharks. The present study investigated the occurrence and size of white sharks (Carcharodon carcharias) in the near-shore environment off Bennett’s Beach, part of a known nursery area for the species in central New South Wales, Australia. Six stereo-BRUV units were deployed approximately fortnightly between August and December 2015 for periods of 5h in depths of 7–14m. Stereo-BRUVs successfully recorded 34 separate sightings of 22 individual white sharks. The highest number of individuals detected during a single day survey was eight. All C. carcharias observed on stereo-BRUVs were juveniles ranging in size from 1.50 to 2.46-m total length (mean±s.e., 1.91±0.05m; n=22). The time to first appearance ranged from 15 to 299min (mean±s.e., 148±15min). This study demonstrates that the use of stereo-BRUVs is a viable, non-destructive method to obtain estimates of the size and presence of white sharks, and may be useful in estimating relative abundance in near-shore environments where white sharks are known to frequent.


2006 ◽  
Vol 4 (2) ◽  
pp. 291-294 ◽  
Author(s):  
Mark D. Bowen ◽  
Simone Marques ◽  
Luiz G. M. Silva ◽  
Volney Vono ◽  
Hugo P. Godinho

On site human observations and video images were collected and compared at the window of the Igarapava Dam fish ladder (IDFL), rio Grande , Southeastern Brazil, between March 1st and June 30th, 2004. We conducted four experiments with two humans (Observer 1 and Observer 2) observing fish passage in the IDFL window while a Sony 3CCD video camera (Observer 3) recorded fish passage at the same time. Experiments, each one hour in length, were distributed throughout the diel cycle using full spectrum lights. We identified fish species, the number of individuals for each species, and the real time that they passed. Counts from each human observer were compared to the video counts. The fish species most commonly observed in the window were - curimba (Prochilodus lineatus), mandi-amarelo (Pimelodus maculatus), piau-três-pintas (Leporinus friderici) and ferreirinha (Leporinus octofasciatus). The number of species and individuals were indistinguishable for the three observers. But, the number of species and individuals were significantly different among experiments. Thus, the three observers register the same number of species and count the same number of individuals even when these two response variables differ significantly among experiments. Based on these results, we concluded that the video count was an accurate method to assess fish passage at the IDFL.


2007 ◽  
Vol 4 (3) ◽  
pp. 1069-1094
Author(s):  
M. Rivas-Casado ◽  
S. White ◽  
P. Bellamy

Abstract. River restoration appraisal requires the implementation of monitoring programmes that assess the river site before and after the restoration project. However, little work has yet been developed to design effective and efficient sampling strategies. Three main variables need to be considered when designing monitoring programmes: space, time and scale. The aim of this paper is to describe the methodology applied to analyse the variation of depth in space, scale and time so more comprehensive monitoring programmes can be developed. Geostatistical techniques were applied to study the spatial dimension (sampling strategy and density), spectral analysis was used to study the scale at which depth shows cyclic patterns, whilst descriptive statistics were used to assess the temporal variation. A brief set of guidelines have been summarised in the conclusion.


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