Production of the Euphausiid Crustacean Thysanoëssa raschii in the Gulf of St. Lawrence

1977 ◽  
Vol 34 (3) ◽  
pp. 443-446 ◽  
Author(s):  
F. Berkes
Keyword(s):  
Field Data ◽  
Zooplankton Biomass ◽  
Total Zooplankton ◽  
Loss Of Weight ◽  
Annual Biomass ◽  
The Mean ◽  
Total Zooplankton Biomass ◽  
Population Numbers

From field data on growth and population numbers, production of Thysanoëssa raschii, excluding molts, was calculated to be about 1.8 mg dry wt∙m−3∙yr−1 in the Gulf of St. Lawrence. The mean annual biomass of T. raschii was 0.47 mg dry wt∙m−3, comprising about 1% of the total zooplankton biomass in the Gulf, and giving a production to biomass (P:B) ratio of about 4. Production and biomass were probably underestimated due to some sampler avoidance, lack of egg to nauplius–metanauplius interval of population production and loss of weight due to leaching in preserved samples.

scholarly journals Influence of net-cage fish farming on zooplankton biomass in the Itá reservoir, SC, Brazil

2012 ◽  
Vol 23 (4) ◽  
pp. 357-367 ◽  
Author(s):  
Bruna Roque Loureiro ◽  
Christina Wyss Castelo Branco ◽  
Evoy Zaniboni Filho
Keyword(s):  
Fish Farming ◽  
Dry Weight ◽  
Control Area ◽  
Zooplankton Biomass ◽  
Total Density ◽  
Total Zooplankton ◽  
Net Cage ◽  
Uruguay River ◽  
Cage Fish ◽  
Total Zooplankton Biomass

OBJECTIVES: This study aimed to verify the influence of net-cage fish farming on zooplankton biomass in the Itá reservoir (Uruguay River, Brazil). METHODS: Samples were collected monthly from October/2009 to May/2010 at the surface and at the bottom in two sampling stations, the net-cage area and in a control area using a Van Dorn bottle and a plankton net (68 µm). RESULTS: The Cladocera and Copepoda biomass was estimated by dry weight using a micro-analytical balance, and the Rotifera biomass by Biovolume. Total zooplankton biomass varied between 6.47 and 131.56 mgDW.m-3 Calanoida copepod presented the highest value of biomass (127.56 mgDW.m-3) and rotifers, despite having an important contribution to total density, showed a maximum biomass of 2.01 mgDW.m-3. Zooplankton biomass at the net-cage area surface was higher when compared with the control area during the months of October to January. However, the zooplankton biomass was similar at the bottom of the two areas throughout the studied period. From February until May, zooplankton biomass decreased in both sampling stations, a fact probably associated with the flushing of the reservoir, followed by an increase in water transparency and a decrease in chlorophyll-a concentration in the following months (February to May). CONCLUSIONS: The influence of fish farming on zooplankton biomass was detected at the surface of the net-cage area only from October to January. From February to May this influence was not found, probably by the influence of the flushing of the reservoir.

scholarly journals Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

1993 ◽  
Vol 62 (4) ◽  
pp. 215-226 ◽  
Author(s):  
Juliana H.M. Kouwenberg
Keyword(s):  
Seasonal Variation ◽  
Coastal Region ◽  
Zooplankton Biomass ◽  
High Abundance ◽  
Total Biomass ◽  
Total Zooplankton ◽  
Copepod Abundance ◽  
Bottom Depth ◽  
Total Zooplankton Biomass ◽  
Northwestern Mediterranean

Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish programme Pélagolion/Leopel in the near-coastal region (≤ 25 m bottom depth), the Rhone dilution zone, the neritic region (≤ 200 m bottom depth), and the oceanic region (200–2000 m bottom depth). Abundance of other zooplanktonic groups was estimated and total zooplankton biomass was determined for the upper 50 m. Copepod abundance was highest during September 1986 (all regions) and July 1987 (neritic). Total biomass was highest during July 1987 and May/June 1988, caused by high abundance of many other zooplankters.

Zooplankton and Trophic State Relationships in Florida Lakes

1983 ◽  
Vol 40 (10) ◽  
pp. 1813-1819 ◽  
Author(s):  
J. S. Bays ◽  
T. L. Crisman
Keyword(s):  
Trophic State ◽  
Size Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Crustacean Zooplankton ◽  
Trophic State Index ◽  
Total Zooplankton ◽  
Eutrophic Lakes ◽  
Florida Lakes ◽  
Total Zooplankton Biomass

Zooplankton, including ciliated protozoans, were collected from 39 Florida lakes of widely ranging trophic state. Annual mean biomass values for different zooplankton groups were regressed against Carlson's Trophic State Index based on annual mean chlorophyll a concentration. Whereas total zooplankton biomass yielded a significant regression with increasing trophic state, microzooplankton (ciliates, rotifers, and nauplii) accounted for more of the relationship than macrozooplankton (cladocera, calanoids, and cyclopoids). Within the microzooplankton, the regression improved with decreasing body size. Macrozooplankton biomass exhibited a weak statistical relationship with lake trophic state, but the different component groups were variable in their response. The dominance within the zooplankton community shifts from macrozooplankton to microzooplankton with increasing trophic state, and the microzooplankton can constitute between 50 and 90% of the total zooplankton biomass in eutrophic lakes. Changes in zooplanktivore community structure with increasing trophic state show that whereas total fish biomass increases, dominance shifts from visually oriented predators, such as bass and bluegill, to pump filter-feeding planktivores, such as gizzard shad (Dorosoma cepedianum). While Florida zooplankton communities are similar in size structure to tropical communities, no statistically significant differences were found between empirical equations of crustacean zooplankton biomass and trophic state determined from temperate and Florida data bases.

scholarly journals Interannual dynamics of zooplankton in the Kola Section of the Barents Sea during the recent warming period

2019 ◽  
Vol 76 (Supplement_1) ◽  
pp. i10-i23
Author(s):  
Irina P Prokopchuk ◽  
Alexander G Trofimov
Keyword(s):  
Barents Sea ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Calanus Finmarchicus ◽  
The Arctic ◽  
Zooplankton Abundance ◽  
Total Zooplankton ◽  
The Barents Sea ◽  
Warming Period ◽  
Total Zooplankton Biomass

Abstract Our research focused on the analysis of interannual variability of zooplankton in the Kola Section (the Barents Sea) in the period of current warming in the Arctic basing on previously unpublished data. The zooplankton community was investigated based on the analysis of 240 plankton samples, collected in late May–early June 2009–2017. A total of 74 zooplankton taxa of nine phyla were identified in the plankton samples, but copepods were the most diverse and numerous taxonomic group. The biodiversity index varied considerably from year to year, but a stable tendency for the index to increase since the beginning of the period studied was observed. Copepods dominated in terms of abundance and biomass, comprising on average 73–96% of the total zooplankton abundance and 81–96% of the total zooplankton biomass. Calanus finmarchicus was the main zooplankton species utterly dominated by abundance and biomass (on average 92 and 97% respectively). Considerable differences in zooplankton abundance and biomass at different stations of the section were observed. Although the investigations were carried out during a warming period, interannual differences in zooplankton abundance and biomass were observed. Zooplankton biomasses were higher in the years with higher temperatures and stronger water inflow.

Zooplankton Seasonal Dynamics and Community Structure in Severn Sound, Lake Huron

1995 ◽  
Vol 30 (4) ◽  
pp. 673-692
Author(s):  
A.F. Gemza
Keyword(s):  
Community Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Point Sources ◽  
Total Zooplankton ◽  
Fish Community Structure ◽  
Calanoid Copepods ◽  
Diacyclops Thomasi ◽  
Annual Means ◽  
Total Zooplankton Biomass

Abstract The limnetic zooplankton of Severn Sound, a eutrophic embayment, were studied between 1978 and 1989. Forty-one species of zooplankton were identified from samples collected in the sound. Total zooplankton biomass ranged seasonally from a minimum of 3.9 mg/m3 at less eutrophic stations to over 1,625 mg/m3 at the most eutrophic sites. Annual means ranged from 38 to 373 mg/m3. At the most eutrophic sites the zooplankton community was dominated by the cladoceran Bosmina longirostris. Cyclopoid and calanoid copepods increased in dominance as conditions approached mesotrophy. Calanoid copepods were insignificant contributors at the eutrophic sites, averaging less than 3% of the total zooplankton biomass. Total zooplankton biomass declined with distance from shore and phosphorus point sources as conditions became less eutrophic. Significant empirical relationships (r>0.79) were measured between zooplankton biomass and total phosphorus and phytoplankton biovolume. Densities of several species, Eubosmina coregoni, Daphnia retrocurva and Diacyclops thomasi declined by over 50% during the 11-year period of study and may be related to a shift in fish community structure.

Zooplankton and the total phosphorus – chlorophyll a relationship: hierarchical Bayesian analysis of measurement error

2008 ◽  
Vol 65 (12) ◽  
pp. 2644-2655 ◽  
Author(s):  
Amy M. Kamarainen ◽  
Freya E. Rowland ◽  
Reinette Biggs ◽  
Stephen R. Carpenter
Keyword(s):  
Measurement Error ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Empirical Studies ◽  
Predictive Ability ◽  
Zooplankton Biomass ◽  
Hierarchical Bayesian ◽  
Total Zooplankton ◽  
Residual Variation ◽  
Total Zooplankton Biomass

Zooplankton grazing is important in resolving residual variation around the total phosphorus – chlorophyll a relationship. In empirical studies, zooplankton body size is often a better predictor of residual variation than zooplankton biomass. We investigate whether higher measurement error associated with zooplankton biomass may explain its lower predictive ability. We collected five replicate zooplankton biomass samples in 19 lakes, allowing us to quantify measurement error in volumetric zooplankton biomass with greater precision than in previous studies. A hierarchical Bayesian model was used to assess the predictive ability of volumetric zooplankton biomass and mean individual zooplankton length, corrected for measurement error. We found consistent effects of total zooplankton biomass, but not zooplankton length, on chlorophyll a. This finding does not appear to be related to the higher precision with which total zooplankton biomass was measured in our study, but rather to ecological factors. Interlake variation outweighed the effects of measurement error in estimating the strength of relationships between zooplankton variables and chlorophyll a. Our findings therefore suggest that studies to estimate zooplankton effects on phytoplankton should allocate resources to study a larger range of lakes over different time periods than to process replicate samples to reduce measurement error.

scholarly journals Permafrost thaw lakes and ponds as habitats for abundant rotifer populations

2017 ◽  
Vol 3 (2) ◽  
pp. 354-377 ◽  
Author(s):  
Paschale N. Bégin ◽  
Warwick F. Vincent
Keyword(s):  
Rapid Change ◽  
Zooplankton Biomass ◽  
Total Zooplankton ◽  
Interference Effects ◽  
Top Down ◽  
Thermokarst Lakes ◽  
Β Diversity ◽  
Order Of Magnitude ◽  
Thaw Lakes ◽  
Total Zooplankton Biomass

Thermokarst lakes and ponds were sampled across a range of permafrost landscapes in subarctic Québec (Nunavik, Canada) to compare their rotifer and other zooplankton characteristics with a set of rock-basin lakes and ponds in the region. A total of 24 rotifer species were identified, with an average of seven taxa per waterbody. Rotifer abundance was an order of magnitude higher in the thaw ponds than in rock-basin waters. In some thaw ponds, rotifers accounted for >50% of the total zooplankton biomass, but for <10% in all of the rock-basin waters. Neither α- nor β-diversity was significantly different between the two waterbody types. Grazing experiments with microspheres (0.5–6 µm diameter) showed that medium-sized particles (2–3 µm) were preferred to smaller and larger particles; clearance rates were <0.05% of the water column per day, implying that the rotifer populations were unlikely to be bottom-up limited by food availability. Rotifer abundance was negatively correlated with cladoceran densities, suggesting possible interference effects. Chaoborus larvae were also present and may exert a top-down control. Thermokarst ponds are currently favorable environments for rotifers, but the rapid change they have begun to experience brings uncertainty about their ongoing capacity to sustain these prolific communities.

scholarly journals LONG-TERM CHANGES OF COPEPODA (CRUSTACEA) ABUNDANCE AND BIOMASS IN THE DANUBE AND ODESA REGIONS OF THE BLACK SEA AS INDICATOR OF WATER QUALITY

2021 ◽  
Author(s):  
Yuliia Kharytonova ◽  
◽  
Vasil Dyadichko ◽  
Keyword(s):  
Black Sea ◽  
Fish Larvae ◽  
Ecological Status ◽  
Zooplankton Biomass ◽  
The Black Sea ◽  
Total Biomass ◽  
Ecological State ◽  
Total Zooplankton ◽  
Main Components ◽  
Total Zooplankton Biomass

Copepoda are the most important zooplanktonic group constituting the primary food for fish larvae and some fishes. Copepoda have the longest life cycles among the Black Sea mesozooplankton, so their biomass and percentage of total zooplankton biomass is greatly reduced by eutrophication. The percentage of Copepoda from the total biomass of zooplankton is a reliable indicator of the ecological status of the water bodies. For the Black Sea marine waters the indicator of “good” ecological status (GES) is the average annual biomass of Copepoda, which exceeds 45% of the total biomass of zooplankton. Changes of total biomass of zooplankton, biomass of Copepoda, the abundance and biomass of dominant species – Oithona davisae Ferrari F. D. & Orsi, 1984, Acartia (Acartiura) clausi Giesbrecht, 1889 and A. (Acanthacartia) tonsa Dana, 1849 in the Danube and Odesa marine regions from 1970 to 2019 were analysed. Also the ecological quality class in the Nort-Western part of Black sea by Copepoda indicators from 2004 to 2017 were established according to Water Framework Directive US. The total zooplankton biomass had been decreasing in Ukrainian waters and % of Copepoda from total zooplankton biomass was increasing. These tendencies shown a positive change in the forage base of commercial planktophagous fishes and ecological class status of the investigated aquatories. The abundance and biomass of O. davisae, A. clausi and A. tonsa were decreased from 2016 to 2019. The highest values of their metrics were in 2016 and the lowest rates observed in 2019. O. davisae, A. clausi and A. tonsa were the main components of copepods number and biomass. The Acartia species formed higher part of Copepoda biomass than O. davisae. The ecological state was “good” (GES) only in Danube-Dnieper coastal waters and Danube delta in 2004–2017 where Copepoda formed more than 45 % of total zooplankton biomass. In waters of Northwester Black Sea bays, shallow and deepwater shelfs the ecological state was “Bad” (notGES), the part of Copepoda was lower than 45 %.

scholarly journals Main characteristics of arrowworms in the Bering Sea (species composition, distribution, biomass, production)

2021 ◽  
Vol 201 (2) ◽  
pp. 416-424
Author(s):  
К. M. Gorbatenko
Keyword(s):  
Species Composition ◽  
Biomass Production ◽  
Bering Sea ◽  
Mesh Size ◽  
Zooplankton Biomass ◽  
Total Zooplankton ◽  
Composition Distribution ◽  
Total Zooplankton Biomass ◽  
Epipelagic Layer ◽  
The Bering Sea

 Zooplankton was sampled from the epipelagic layer (0–200 m) in the Bering Sea using Jedae net (mouth 0.1 m2, mesh size 0.168 mm) in 1986–2018. Arrowworms were the most numerous predators, represented with 3 species: Parasagitta elegans, Eukrohnia hamata, and Pseudosagitta maxima. Their summary biomass was 215.7 mg/m3, on average (26.3 % of the total zooplankton biomass), and varied seasonally from 105.9 mg/m3 in winter to 311.8 mg/m3 in autumn. Parasagitta elegans dominated absolutely (> 99 % WW). Mean stock of this species was 64.36. 106 t; its seasonal yield was estimated as 22.1. 106 t in winter, 78.5. 106 t in spring, 191.9. 106 t in summer, and 130.3. 106 t in autumn, so its mean production was 422.8. 106 t WW per year.

scholarly journals Winter Zooplankton in a Small Arctic Lake: Abundance and Vertical Distribution

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 912
Author(s):  
Vladimir G. Dvoretsky ◽  
Alexander G. Dvoretsky
Keyword(s):  
Vertical Distribution ◽  
Deep Water ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Trophic Levels ◽  
Arctic Lakes ◽  
The Arctic ◽  
Total Zooplankton ◽  
Total Abundance ◽  
Total Zooplankton Biomass

Zooplankton assemblages are of great importance in aquatic food webs because they link lower (microplankton) and higher trophic levels (top predators). Small water bodies in the Arctic regions of Russia are less studied in winter because of severe ice conditions. For this reason, we analyzed the winter zooplankton community in Lake Kulonga (western coast of Kola Bay, Barents Sea). A total of 9 taxa were found in the samples. The total abundance varied from 200 to 1320 ind. m−3, averaging 705 ind. m−3. The total zooplankton biomass was 1.8–72.8 mg of wet mass m−3 with an average of 30 mg m−3. These parameters were lower than in other Russian Arctic and sub-arctic lakes in summer. Old copepodites of Cyclops spp. dominated the zooplankton community at deep-water stations in terms of the total abundance consisting of 24–33%. The copepod Macrocyclops albidus prevailed in terms of the total zooplankton biomass comprising 30–33% at deep-water stations while Cyclops scutifer and copepodites Cyclops spp. had the highest biomass at shallow water stations. Vertical distribution demonstrated different patterns at neighboring stations, probably as a result of differences in the density of fish predators.

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