Long-term changes in Baltic herring (Clupea harengus membras) growth in the Gulf of Finland

2004 ◽  
Vol 61 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Sanna Rönkkönen ◽  
Evald Ojaveer ◽  
Tiit Raid ◽  
Markku Viitasalo

We used the longest available weight-at-age (WAA) time series (from 1950 to 1999) for Baltic herring (Clupea harengus membras L.) in the Gulf of Finland to investigate which environmental factors affect Baltic herring growth. The relationships among WAAs, annual weight increments, and growth rates for different herring year classes, water salinity, temperature, zooplankton abundance, and biomass, as well as stock sizes of herring, sprat, and cod, were evaluated. Our results showed that in the Gulf of Finland, herring weight and growth rate correlated positively with salinity, and WAA correlated positively with the abundance of the marine zooplankton species Pseudocalanus minutus elongatus. A density-dependent mechanism was not likely to explain the changes in herring WAA in the Gulf of Finland, because no significant correlation between herring WAAs and herring abundance could be found. Instead, the zooplankton community structure changed during the research period, which supports the theory of bottom-up controlling mechanism. A strong negative correlation between herring weight and sprat biomass may indicate competition for food between these species.

1983 ◽  
Vol 40 (11) ◽  
pp. 1912-1924 ◽  
Author(s):  
J. Anthony Koslow

A simulation model was used to examine whether predatory interactions may regulate the size structure of marine zooplankton communities, as observed in many freshwater systems. Results of the model were consistent with the freshwater studies, such that large increases or decreases in planktivorous fish led to the dominance of small or large zooplankters, respectively. However, model predictions were not consistent with the recent decline in the northeastern Atlantic of most major elements of the pelagic zooplankton community along with North Sea herring and mackerel stocks. The overall decline of the pelagic community throughout this region indicates that zooplankton abundance may be regulated by physical forcing, and that these populations may be food- rather than predator-limited. Realistic ecological simulations of marine pelagic systems may require more complex two-layer models allowing for the effects of vertical migration, and with day–night differences in food availability and selectivity.


2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Arief Rachman ◽  
Elly Asniariati

<p>Banggai Sea is an interesting ecosystem due to mixing influences from Banda Sea in the west and Maluccas Sea in the east. Therefore, a unique zooplankton community structure and specific distribution pattern should be found in this area. This research was carried on using Baruna Jaya VIII research vessel and samples were collected in 14 sampling stations. Vertical towing using NORPAC plankton net (300 μm) was conducted to collect zooplankton samples. Result showed that inner Mesamat Bay had the lowest abundance of zooplankton, probably due to low water quality resulted from anthropogenic activity. Meanwhile the strait between Liang and Labobo Island had the highest zooplankton abundance in Banggai Sea. Calanoids was the dominant zooplankton taxa in the ecosystem and contributing 55.7% of total density of zooplankton community. The highest importance value made this taxa to be very important factor that regulates the lower trophic level organisms. Results also showed that zooplankton was distributed nearly uniform in eastern but aggregated to several stations in western Banggai Sea. Zooplankton abundance was higher in the central of Banggai Sea, compared to western and eastern area. According to Bray-Curtis clustering analysis the strait between Liang and Labobo Island has unique zooplankton community structure. This might happened due to mixing of water from two highly productive seas that influenced the Banggai Sea ecosystem. From this research we conclude that this strait probably was the zooplankton hot spot area which might also indicate that this area also a hot spot of fishes in the Banggai Sea.</p><p>Keywords: spatial distribution, zooplankton, community structure, hot spot, Banggai</p>


1989 ◽  
Vol 46 (5) ◽  
pp. 810-817 ◽  
Author(s):  
Mark R. S. Johannes ◽  
Donald J. McQueen ◽  
Tom J. Stewart ◽  
John R. Post

A winterkill at Lake St. George, Ontario eliminated most of the piscivorous fish and some of the planktivores and also influenced zooplankton community structure. This disturbance and the subsequent recovery of the populations provided the opportunity to evaluate potential impacts of food and predators on the population structure and abundance of the dominant planktivore; the golden shiner (Notemigonus crysoleucas). interpretation of the 8-yr data set suggested that there was a positive relationship between adult golden shiner condition and zooplankton abundance, but that this did not translate into a significant stock–recruitment relationship between female numbers and young-of-the-year (YOY) recruitment. Also, there was no significant relationship between golden shiner survival and zooplankton abundance. However, there were significant negative correlations between YOY and adult golden shiner survival estimates and predator abundances. We conclude that at Lake St. George, golden shiner recruitment and population density is strongly influenced by predator density and is not influenced by food abundance.


2018 ◽  
Vol 16 (4) ◽  
pp. 209-221 ◽  
Author(s):  
Anni Djurhuus ◽  
Kathleen Pitz ◽  
Natalie A. Sawaya ◽  
Jaimie Rojas-Márquez ◽  
Brianna Michaud ◽  
...  

Elem Sci Anth ◽  
2015 ◽  
Vol 3 ◽  
Author(s):  
Stephanie E. Wilson ◽  
Rasmus Swalethorp ◽  
Sanne Kjellerup ◽  
Megan A. Wolverton ◽  
Hugh W. Ducklow ◽  
...  

Abstract The Amundsen Sea Polynya (ASP) has, on average, the highest productivity per unit area in Antarctic waters. To investigate community structure and the role that zooplankton may play in utilizing this productivity, animals were collected at six stations inside and outside the ASP using paired “day-night” tows with a 1 m2 MOCNESS. Stations were selected according to productivity based on satellite imagery, distance from the ice edge, and depth of the water column. Depths sampled were stratified from the surface to ∼ 50–100 m above the seafloor. Macrozooplankton were also collected at four stations located in different parts of the ASP using a 2 m2 Metro Net for krill surface trawls (0–120 m). The most abundant groups of zooplankton were copepods, ostracods, and euphausiids. Zooplankton biovolume (0.001 to 1.22 ml m-3) and abundance (0.21 to 97.5 individuals m-3) varied throughout all depth levels, with a midsurface maximum trend at ∼ 60–100 m. A segregation of increasing zooplankton trophic position with depth was observed in the MOCNESS tows. In general, zooplankton abundance was low above the mixed layer depth, a result attributed to a thick layer of the unpalatable colonial haptophyte, Phaeocystis antarctica. Abundances of the ice krill, Euphausia crystallarophias, however, were highest near the edge of the ice sheet within the ASP and larvae:adult ratios correlated with temperature above a depth of 60 m. Total zooplankton abundance correlated positively with chlorophyll a above 150 m, but negative correlations observed for biovolume vs. the proportion of P. antarctica in the phytoplankton estimated from pigment ratios (19’hexanoyloxyfucoxanthin:fucoxanthin) again pointed to avoidance of P. antarctica. Quantifying zooplankton community structure, abundance, and biovolume (biomass) in this highly productive polynya helps shed light on how carbon may be transferred to higher trophic levels and to depth in a region undergoing rapid warming.


2020 ◽  
Vol 32 (3) ◽  
pp. 168-179 ◽  
Author(s):  
V. Venkataramana ◽  
N. Anilkumar ◽  
K. Swadling ◽  
R.K. Mishra ◽  
S.C. Tripathy ◽  
...  

AbstractThe community composition of zooplankton with an emphasis on copepods was assessed in the frontal zones of the Indian sector of the Southern Ocean (SO) during summer 2013. Copepods were the dominant group in both the bongo net and multiple plankton sampler across the entire region. High zooplankton abundance was recorded along each transect in the Polar Front (PF). Community structure in this front was dominated by common taxa, including Ctenocalanus citer, Clausocalanus spp., Calanoides acutus, Calanus propinquus, Calanus australis and Rhincalanus gigas, which together accounted for > 62% of the total abundance. Calocalanus spp., Neocalanus tonsus and C. propinquus were indicator species in the Sub-Tropical Front (STF), Sub-Antarctic Front and PF, respectively. A strong contrast in population structure and biovolume was observed between then PF and the STF. The community structure of smaller copepods was associated with the high-temperature region, whereas communities of larger copepods were associated with the low-temperature region. Thus, it seems probable that physical and biological characteristics of the SO frontal regions are controlling the abundance and distribution of zooplankton community structure by restricting some species to the warmer stratified zones and some species to the well-mixed zone.


1993 ◽  
Vol 27 (7-8) ◽  
pp. 353-361 ◽  
Author(s):  
B. Pinel-Alloul

Excessive concentrations of phosphorus are a common feature of hardwater eutrophic lakes in western Canada. Preliminary experimental lime treatment showed that this approach had a great potential to reduce phosphorus content and algal biomass. Therefore, two pairs of experimental and reference lakes were selected for a whole lake lime treatment and monitored for a full year prior to manipulation. This study presents the composition and size structure of the Zooplankton community of the lakes before treatment in order to assess the natural summer and inter-lake variations. Before lime treatment, seasonal means of total Zooplankton abundance and biomass ranged from 17 ± 8 to 127 ± 84 ind. L−1 and from 4 ± 2 to 138 ± 236 mg m−3, respectively. The two experimental lakes (Halftnoon and Lofty) were the richest in Zooplankton while the references lakes (Crooked and Jenkins) were the poorest. A total of 30 Zooplankton species (17 rotifers, 2 calanoids, 4 cyclopoids and 7 cladocerans) were recorded as well as 3 chaoborid species. The composition and size structure of Zooplankton varied between lakes and dates. Rotifers accounted for the majority of Zooplankton abundances (59-91%) while Cladocera (78-99%) or Copepoda (74%) in Crooked lake formed most of the Zooplankton biomass. Summer variations of the Zooplankton groups were described along with changes in size spectra. The temporal variation and the inter-lake differences in Zooplankton structure were discussed in relation to trophy, fish and invertebrate predation, and cyanophyte interactions.


2017 ◽  
Vol 74 (8) ◽  
pp. 1218-1232 ◽  
Author(s):  
Mika Rahikainen ◽  
Kirsi-Maaria Hoviniemi ◽  
Samu Mäntyniemi ◽  
Jarno Vanhatalo ◽  
Inari Helle ◽  
...  

The Baltic Sea is one of the world’s most stressed sea areas. Major threats to the ecosystem include eutrophication and oil spills. The progression of anthropogenic nutrient enrichment is lengthy and gradual, while oil spills cause rapid changes in the system, with varying impact time. We quantify the impact of eutrophication and the key ecological covariates on the population dynamics of the major pelagic fish stock, the Baltic herring (Clupea harengus membras), in the Gulf of Finland. The full life cycle of herring is represented with a probabilistic state-space model. Moreover, we analyse the impact of the oil spill from M/T Antonio Gramsci in 1987 on herring survival. The results confirm impact of the spill on the early life-stage survival; the observed high frequency of malformed herring larvae in surveys signaled elevated mortality of the year class. The optimal July–August chlorophyll a concentration for herring reproduction is approximately 5 μg·L−1. This level is currently exceeded, suggesting recruitment impairment due to eutrophication. The herring stock was also recruitment-overfished. Analysis suggests deceleration of herring growth as salinity descends below 6 psu.


2018 ◽  
Vol 66 (2) ◽  
Author(s):  
Johanna Medellín-Mora ◽  
Rubén Escribano ◽  
Wolfgang Schneider ◽  
Marco Correa-Ramírez ◽  
Nestor Campos

Zooplankton is an important component to understand oceanographic dynamics, they are considered good indicators of environmental variability, since most species are short-lived they can be tight coupling of climate and population dynamics, and some taxa are sensitive to variables such as temperature, quality and quantity of food, oxygenation and stratification. In the Colombian Caribbean two oceanographic cruises were carried out, in order to characterize and analyze the biodiversity of the continental margin, for the periods May-June 2008 and November-December 2009. The objective of this study was to determine which oceanographic variable was the most important in the distribution of zooplankton in the oceanic waters, and how the variables structure the community. In each cruise, zooplankton samples were obtained by vertical hauls with a 1 m2 diameter conical net (200 μm mesh size). The zooplankton community structure was studied by automated image analysis (ZooImage), which combined with abundance data, allowed to calculate the slope of size spectrum, and diversity indexes of taxa and sizes. The environmental variables included temperature, salinity, oxygen and chlorophyll a of the water column, and were used to calculate the stratification with the Brunt-Vaiisala frequency; this information was complemented by satellite images of temperature, surface chlorophyll, geostrophic currents and sea level, obtained from MODIS and AQUA products. The association between environmental variables and the zooplankton community structure was determined using Spearman’s correlation ranges with the Bioenv routine and a stepwise regression model, and Principal component analysis (PCA). Our results showed spatial and temporal patterns in the oceanographic conditions of the study area, such as upwelling in the Northeast region, strong stratification in the Southwest, and mesoscale activity. The abundance of zooplankton exhibited differences between the two climatic seasons and zones. Temporal differences were also evident in the size and diversity of taxa (ANOVA 2-way p <0.05). These changes were related to the moderate upwelling and the activity of mesoscale eddies. Cyclonic and anticyclonic eddies of variable size can either transport or retain zooplankton over cross-shelf and oceanic areas, thus modifying the taxonomic structure of the community. According to the Bioenv analysis, the main variables that explained the abundance and composition of zooplankton were sea level and chlorophyll a (Spearman correlation = 0.49). The stepwise regression showed that stratification, oxygen and chlorophyll a were the most important predictors of zooplankton abundance and size. Rev. Biol. Trop. 66(2): 688-708. Epub 2018 June 01. 


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