Find the information such as human life, natural resource,agriculture,forestry, biotechnology, biodiversity, wood and non-wood materials.
Blog List
Thursday, 19 January 2017
The comparative statuses of the Far Eastern seas and the northwestern Pacific Ocean based on the range of integral characteristics of pelagic and bottom trawl macrofauna
Published Date
Journal of Asia-Pacific Biodiversity 30 March 2015, Vol.8(1):31–37,doi:10.1016/j.japb.2015.01.006 Open Access, Creative Commons license,Funding information Original article
Author
Igor V. Volvenko,
Pacific Research Fisheries Center (TINRO-Center), per. Shevchenko 4, Vladivostok, Russia
Received 19 November 2014. Revised 22 January 2015. Accepted 23 January 2015. Available online 3 February 2015.
Abstract Comparison of the pelagial and benthal of the Far Eastern seas (mainly within the borders of the Russian EEZ) and the contiguous part of the Pacific Ocean according to the macrofauna population density, species richness, evenness and diversity, and average individual weight of animals, is provided on the basis of the results of multiannual broad-scale pelagic and bottom trawl surveys carried out in 1977–2010. Keywords
abundance
diversity
size of animals
species evenness
species richness
Introduction
As can be determined from the title of this article, the topic is macrofauna (all animals with a body size ≥ 1 cm) of the northwestern Pacific. However, according to the data available to me, more or less complete information will be provided here not for the entire northwestern quarter of the Pacific Ocean, but only for the Russian EEZ with the adjacent neutral waters and a part of the economic zones of Japan and the Democratic People’s Republic of Korea where, in accordance with intergovernmental agreements, works with involvement of Russian scientists were carried out (Figure 1). These are mainly the subarctic ocean waters, the northwestern third part of the East Sea, the western part of the Bering Sea (also nearly one-third of the water body’s area) and so on, but for the sake of brevity in this article these will be referred to as the Pacific Ocean (or simply Ocean), the East Sea, the Sea of Okhotsk, the Bering Sea and the northwestern Pacific (or the whole region). One more preliminary specification is connected with the method of basic data collection: the pelagic macrofauna in this article refers to the animals caught in the process of pelagic trawling into the midwater trawl with a fine-mesh insertion of 10–12 mm webbing, sewn into its cod end over the length of the last 12–15 m, and the benthic or bottom-dwelling macrofauna stands for the animals, caught into bottom trawls also equipped with a fine-mesh insertion (Table 1).
Figure 1. Location of the trawl stations on the explored water areas of the four water bodies, for which the integral properties of macrofauna were calculated.
Table 1. Composition of the studied macrofauna (number of species in brackets).a
The subject of comparison is six emergent integral properties of macrofauna, characterizing it as a whole:
(1) and (2)
The total number N (ind./km2) and biomass M (kg/km2) of all the specimens – measures of abundance, population density, reflecting the potential reserve of renewable biological resources, productivity of the ecosystem, which provides their reproduction, as well as the intensity of the biogeochemical cycle and the realized ecological environmental capacity in the area of location of this system;
(3)
The average weight of individual W (kg/ind.) – characteristic of average size, mean metabolic rate of the animals, quantity of the resources consumed by them, power and mobility of the individuals, and size of their feeding area, as well as share of carnivores among them;
(4)
Species richness S (number of species) – measure of the taxonomic diversity and of the number of realized ecological niches;
(5)
Evenness of species abundances according to Pielou (1966)J (unit fraction) – index of equitability of specimens to species, synonym of “polydominance” of biocenotic assemblages, the value inversely proportional to the expressiveness of dominance of the dominant species over the others (“monodominance” or “oligomixity”), characteristic of homogeneity of the structure and the complexity of the community’s architecture;
(6)
Species diversity according to Shannon (1948)H (bit/ind.) – measure of uncertainty – ambiguity of belonging of a randomly chosen specimen to a certain species, index of suitability of a certain water area for monospecific or multispecific fishery.
The same water areas have already been compared between one another 5 years ago according to the six aforementioned properties (Volvenko 2009d). For that purpose they used the data of 19,436 pelagic trawl stations, made in 160 scientific research expeditions, carried out by the “TINRO-Center” institute from December 24, 1979 to November 30, 2005. From then, onward data from more than 22,000 trawl stations, most of which are benthic, were added to the available materials. This provided an opportunity to verify and specify the previously made comparisons of the water bodies based on the pelagic macrofauna, supplementing them with the comparisons of the benthic macrofauna, as well as with the comparison between the benthal and pelagial. In this manner the purpose and the objectives of this article are defined.
Materials and methods
The source materials for calculations were taken from the two databases (Volvenko and Kulik, 2011 and Volvenko, 2014b) containing the information on macrofauna from 41,596 trawl stations, made during 33 years (to be more accurate, from June 15, 1977 until September 6, 2010) with involvement of TINRO’s employees in 305 scientific research expeditions, which were carried out for the purpose of monitoring of the state of ecosystems and bioresources of the northwestern part of the Pacific Ocean and the contiguous seas (Table 2). These data were previously used for preparation of eight reference books, integrating in a tabular form the information on the species composition, occurrence, and abundance of the macrofauna of the pelagial (Pelagic macrofauna, 2012a–c) and benthal (Benthic macrofauna, 2014a–e) of the area under survey.
Table 2. Sample values, made in the pelagic water layer and (after the/) near the bottom.
Water body
Explored area, thous. km2
No. of trawl stations
No. of specimens caught, mln. ind.
Bering Sea
886/342
3543/4126
38.4/6.8
Sea of Okhotsk
1486/1368
8100/6763
63.5/20.6
East Sea
425/199
2343/5395
20.4/7.4
Pacific Ocean
3116/333
8459/2867
251.4/11.4
Whole water area
5912/2243
22,445/19151
373.7/46.2
It is necessary to note that the vessels working there could trawl at a depth of ≤ 2025 m, so the bottom stations are placed close to the shoreline as the pelagic ones and cover a significantly smaller area (see Figure 1, Table 2). Subsequently: (1) in the databases there are no materials about the deep-dwelling trawling nekton, benthos, and nektobenthos; (2) fusion of the data from the pelagic and benthic trawlings for the calculation of the general integral properties of the macrofauna of the whole water massive is incorrect, and for that reason the pelagial and benthal are considered separately from each other.
For the sake of convenience of comparison the results achieved are presented in three formats: in two tables – with numeric characteristics of the integral properties and with the range of water bodies according to these characteristics, as well as in graphic form. By construction of charts the following considerations previously published (Volvenko 2009d) were taken into account.
The diversity of species is unambiguously defined by two of its components H = J·logS. The biomass can also be expressed in terms of a simple product M = N·W. Thus, only four axes – J, S, N, and W – are needed for the formation of a virtual space, where each water body may be presented as a point, the location of which in relation to the other equivalent points will sufficiently characterize its comparative state according to the six integral properties altogether. Such a presentation simplifies and makes evident the natural ecologic and/or biogeographic classification of the water bodies. The formal complexity consists only in the fact that it is impossible to render all four variables together in one three-dimensional space, and four- and more dimensional spaces are difficult to perceive for us – inhabitants of a three-dimensional world. Because of these limitations it turns out that the interrelations of any three variables can be visually demonstrated by one solid figure, and all the possible relations of the four variables – only by four solids. Thus, N, J, S,and W give four different combinations by three at a time: (1) NJS, (2) NWS, (3) JWS, and (4) NJW. These four three-dimensional projections are presented in Figure 2, intended for visual comparison of the pelagial and benthal of different water bodies. All the projections of N and W were preliminarily converted into logarithmic form for the convenience of presentation of the variables with lognormal frequency distribution.
Figure 2. The comparative status of different water bodies, presented in the form of their mutual arrangement in the three-dimensional space of the integral properties. Here and in Figure 3 the dark points correspond to the pelagial, the light ones – to the benthal. Along the X-, Y,- and Z-axes: lgN and lgW – common logarithms of the average population density in the units of quantity and the average individual weight of the specimen. A = the whole explored area; B = Bering Sea; E = East Sea; J = index of equitability of a number of specimens to species, O = Sea of Okhotsk; P = waters of the Pacific Ocean, S = species richness.
Results and discussion
The aforementioned forms of comparison of different seas between each other (Table 3 and Table 4, Figure 2) demonstrate the following peculiarities characteristic of them:
Table 3. Integrative characteristics of pelagic and (after the/) benthic macrofauna.
Water body
Total abundance
Average mass of an animal
Species richness
Evenness
Diversity
N
M
W
S
J
H
thous. ind./km2
t/km2
kg/ind.
species
unit fraction
bit/ind.
Bering Sea
562.307/89.745
7.874/28.146
0.014/0.314
277/552
0.371/0.389
3.014/3.544
Sea of Okhotsk
439.312/740.347
12.043/16.654
0.027/0.022
393/820
0.380/0.224
3.277/2.168
East Sea
234.650/126.562
6.606/14.472
0.028/0.114
185/593
0.317/0.520
2.386/4.786
Pacific Ocean
213.738/79.971
5.771/32.928
0.027/0.412
608/669
0.395/0.344
3.649/3.228
Whole water area
324.151/488.564
7.722/20.633
0.024/0.042
825/1306
0.438/0.251
4.248/2.575
Table 4. Ranging of the water bodies according to the six integral characteristics.
Place
N
M
W
S
J
H
pel.
ben.
pel.
ben.
pel.
ben.
pel.
ben.
pel.
ben.
pel.
ben.
1
B
O
O
P
E
P
P
O
P
E
P
E
2
O
E
B
B
P≈O
B
O
P
O
B
O
B
3
E
B
E
O
O≈P
E
B
E
B
P
B
P
4
P
P
P
E
B
O
E
B
E
O
E
O
ben.= benthal; B = Bering Sea; E = East Sea; O = Sea of Okhotsk; P = waters of the Pacific Ocean; designation of the properties as in Table 3; pel. = pelagial.
The pelagial of the East Sea differs from the pelagial of all the other seas by the largest average sizes of animals and the lowest indexes of the remaining properties: population density (according to the number and biomass), species diversity and its components – species richness and evenness. The macrofauna of the benthal of this sea is also characterized by the minimal biomass, but intermediate values of sizes, numbers, and species richness, and due to the greatest evenness based on the abundance of species, the diversity of the benthic population of the East Sea is higher than that of the other seas.
In the pelagial of the Sea of Okhotsk dwell almost as large hydrobionts, as in the pelagial of the East Sea, but their number is significantly greater, and the other characteristics—biomass, species richness, evenness, diversity—have the maximal quantities among all of the considered Far Eastern seas. The benthal of the Sea of Okhotsk differs from the others by the smallest sizes of hydrobionts; that is why here, regardless of the largest number of the benthic population, its biomass appears to be average. In addition, regardless of the record species richness, the species diversity here is minimal due to the lowest species evenness based on the number of individuals.
For the pelagial of the Bering Sea registered maximal number, the smallest animals and average other characteristic. The benthal of this sea is characterized by the smallest values of the species richness and their numbers. Because of the largest sizes of the individuals, their total biomass turns out to be maximal. The species evenness and diversity of the benthic population are on an average level.
In the pelagial of the Pacific waters the abundance of macrofauna is lower than in the seas, but their species richness, evenness, and diversity are higher, and the average size of animals are nearly the same as in the Okhotsk and the East Seas. In the benthal of the ocean the number of hydrobionts is also lower than in the contiguous seas. However, due to the largest sizes of the specimens dwelling here, their total biomass is significantly higher than the biomass of other habitat groups. The species diversity and both of its two components are presented here at the average levels.
The integral properties, calculated for the pelagic macrofauna of the whole region under survey, consistently differ from those calculated for separate water bodies. The species diversity grows, as it comprises all the species dwelling in every basin. The species evenness of the composition also grows as all the local areas of dominance of different dominant species are maximally averaged. Accordingly, the diversity also grows. All the other properties – number, biomass, average weight of an animal – take the arithmetic average (weighted average) values for all the water bodies belonging within the area under survey. In the benthal of the northwestern Pacific nearly the same is observed, but the equitability of specimens to species by the smoothing of data from the whole explored water area does not grow. That is why the diversity of species does not grow either.
Generally, it appears that addition of the multiple new data provided an opportunity to specify the previously published (Volvenko 2009d) quantities of the integral characteristics of the pelagic macrofauna (Table 3), but at that no changes in the status of different water bodies according to any of the indexes appeared (Table 4, Figure 2). Along with this, totally different interrelations were acquired for the benthal — according to all of the considered integral characteristics of the benthic macrofauna the water bodies are ranged in a different order.
By comparison of the pelagic and benthic macrofaunas (Table 3), the following patterns are discernible.
First, the quantity of the benthic population is, as a rule, lower than the pelagic one (the exception is the Sea of Okhotsk), but the biomass is always greater. It is mostly explained by the larger sizes of the inhabitants of the benthal (the Sea of Okhotsk is again the exception).
Second, near the bottom more species dwell than in the mid-water layer, but the ultimate value of the species diversity is defined not by its richness, but by the equitability of specimens to species: the greater the equitability, the greater is the diversity. That is why in the Bering and in the East Seas the benthic population is more diverse than the pelagic one, and in the Sea of Okhotsk and in the Ocean, on the contrary.
In addition, the distances between the points in Figure 2 show that the benthal of the Sea of Okhotsk, according to interrelation of the integral characteristics, appears to be close to the pelagial of that sea and of the other water bodies, probably because of its relative shallowness, the largest area of the shelf. Accordingly, the benthic macrofaunas of the East Sea, the Bering Sea and the Pacific Ocean are similar to each other according to the integral characteristics and significantly differ from the other habitat groups. The properties of the oceanic macrofauna are much closer to the properties of the Bering Sea than to those of the East Sea, apparently, because the latter is connected to the Ocean by very shallow and narrow straits. It hinders the transit of the inhabitants of the bottom and of the bottom waters through them.
Now let us pay attention to the interrelations of different integral properties. The ranging of the water bodies (Table 4) according to J and H both in the pelagial and in the benthal, and in the pelagial according to S, J, and H, fully coincides. This means that according to these characteristics a 100% positive rank correlation is observed. In the benthal, S with H and N with W correlate negatively. Pair Pearson correlations, unlike the rank correlations, are statistically significant only for the positive relations Mwith W in the benthal (r = 0.952, p = 0.048), H with J in the pelagial (r = 0.974, p = 0.026) and in the benthal (r = 0.999, p = 0.001). The two latter correlations once again quantitatively confirm the conclusion drawn previously (ref. also to: Volvenko, 2007, Volvenko, 2008 and Volvenko, 2009a) about the fact that in the northwestern Pacific the diversity mostly depends not on the species richness, but on the equitability of specimens to species.
Comparison of the data from Table 2 and Table 3 showed a difference for the pelagial and the benthal, but in all the cases there was a statistically significant positive dependence of the species richness on the sampling size (Figure 3). This long-known (ref. to e.g.: Watson, 1835, Jaccard, 1908, Arrhenius, 1921, Gleason, 1922 and Preston, 1948) regularity means that in the course of time with continuation of the monitoring any estimations of the richness of species are sure to increase. We can estimate by how much they will increase, using numerous specific methods (Sukhanov, 1991, Bunge and Fitzpatrick, 1993, Colwell and Coddington, 1994, Nichols and Conroy, 1996, Boulinier et al., 1998, Chazdon et al., 1998, Chao, 2005and Colwell, 2013; and many others), which give different results. But in this article estimates of the potential number of species which can be found in each reservoir of the northwestern Pacific are not given. Instead, only real data of the actual observations are provided (Table 3). The main aspect is that Figure 3 confirms the aforementioned comparisons of the pelagial and the benthal: no matter how fully the checklists would be completed with notes of rare, numerically insignificant species, other factors being equal, the richness of benthic species would be significantly greater than that of the pelagial species.
Figure 3. Dependence of the species richness (S) – Y-axis on the size of sampling: the explored area (A, thous. km2), number of trawl stations (Nst, units), and number of caught individuals (Nind, mln. of ind.) – X-axis. The data are taken from Table 2. The indications of the points are the same as in Figure 2.
At last, it is essential to refer to the monograph, dedicated to the biology of the Far Eastern seas of Russia (Shuntov 2001), where on page 540 generalization of the reported data is given in a tabular form, where the same basins of the northwestern Pacific are structured according to the concentration of biogenes, primary production, biomasses of nekton (fishes and squids), and of bottom-dwelling benthos (benthic invertebrates), but unfortunately, the source quantitative data are not provided for all of the characteristics. In the mentioned Table (Shuntov 2001, Table 211)for the biomasses of nekton and benthos the water bodies are placed in a different order. Particularly, the Bering Sea is leading according to both of the characteristics. Most likely, the differences are explained by the inconsistency of the source data. Comparisons of abundance of the whole macrofauna of the pelagial and benthal with the abundance of nekton, as well as abundance of the bottom trawling macrofauna with abundance of bottom-grab benthos, are not entirely correct. More than that, benthic trawl surveys encompass significantly smaller areas rather than the bottom-grab ones, especially in the ocean. One should also note that the estimations of the abundance of fishes and squids are given in the monograph for the whole Bering Sea, and in the current article, only for the northwestern part of it. In the monograph, the data for the pelagial of the East Sea are provided only for the 1980s, when there were large amounts of pollock and Pacific sardine, and in this article they are averaged with the data of the following decades.
In addition, by comparison of the data presented in Table 211 in the monograph (Shuntov 2001) with the data in Table 3 and Table 4 in this paper positive rank correlations of the number of pelagic population with the nekton biomass (at that Pearson pair correlation of the average number with the biomass upper limit of r = 0.991, p = 0.009) and concentration of biogenes with the benthic population biomass were found (there are no quantitative data on the biogenes for calculation of r and p in Table 211 of V.P. Shuntov 2001). Taking into consideration low compatibility of catch tools, regions, and terms data, these correlations can be treated as accidental. But both of them are rationally interpreted. (1) The main part of the pelagic population consists of nekton, the biomass of which is directly proportional to its number (Volvenko, 2009b and Volvenko, 2009c). (2) The biogenes concentration correlates positively along with the biomass of the benthic population, not the pelagic one, due to the fact that organic substance of low trophic levels (the biomass of which depends on availability of biogenes) is not fully ingested by the pelagic population in the northwestern Pacific, and the substantive part of it comes to organic debris, filling the ecosystem energy reserve available only for benthos and nektobenthos (Dulepova 2002).
Finally, note that this article provides only the utterly generalized comparative characteristic of water bodies with averaged data on maximum possible place-time scales – >30 years and thousands of square kilometers. Actually, the spread of integral properties inside each of the water bodies is far from homogeneous. The main consistent patterns of their space variability in the northwestern Pacific water area are examined in other publications (Volvenko, 2009e, Volvenko, 2012 and Volvenko, 2014a).
Acknowledgments
The author expresses his gratitude to Professor V.P. Shuntov (TINRO-Center) for discussion of the main points of this paper and useful remarks, which were considered during the manuscript preparation.
Benthic macrofauna of Peter the Great Bay (Japan/East Sea): occurrence, abundance, and biomass. 1978–2009. 2014a. Vladivostok: TINRO-Centre (In Russian).
Benthic macrofauna of the northwestern part of Japan (East) sea: occurrence, abundance, and biomass. 1978–2010. 2014b. Vladivostok: TINRO-Centre (In Russian).
Benthic macrofauna of the western part of the Bering Sea: occurrence, abundance, and biomass. 1977–2010. 2014e. Vladivostok: TINRO-Centre (In Russian).
Statistical methods for estimating species richness of woody regeneration in primary and secondary rain forests of NE Costa Rica
Forest biodiversity research, monitoring and modeling: Conceptual background and old World case studies, 1998, Parthenon Publishing, Paris, pp. 285–309
Pelagic macrofauna of the western part of the Bering Sea: occurrence, abundance, and biomass. 1982–2009. 2012c. Vladivostok: TINRO-Centre (In Russian).
General Patterns of Spatial-temporary Distribution of the Integral Characteristics of Pelagic Macrofauna of the North-Western Pacific and Biological Structure of Ocean
Journal of Earth Science and Engineering, Volume 2, 2012, pp. 1–14
General patterns of spatial distribution of the integral characteristics of benthic macrofauna of the northwestern Pacific and biological structure of ocean
Open Journal of Ecology, Volume 4, 2014, pp. 196–213
No comments:
Post a Comment