Eurytemora affinis (Poppe, 1880) (Copepoda, Calanoida) in the Gulf of Riga, Baltic Sea — elemental composition and diurnal vertical migration

Crustaceana ◽  
2020 ◽  
Vol 93 (3-5) ◽  
pp. 447-466
Author(s):  
Astra Labuce ◽  
Solvita Strake ◽  
Inta Dimante-Deimantovica
Keyword(s):  
Surface Layer ◽  
Baltic Sea ◽  
Elemental Composition ◽  
Vertical Migration ◽  
Clupea Harengus ◽  
Elemental Content ◽  
Eurytemora Affinis ◽  
Diurnal Vertical Migration ◽  
Trade Offs ◽  
Gulf Of Riga

Abstract The present paper reports the results of two surveys conducted in the Gulf of Riga (Baltic Sea) during 1997. Elemental composition (carbon and nitrogen) and diurnal vertical migration (DVM) throughout development of the calanoid copepod Eurytemora affinis (Poppe, 1880) were studied. This is a species with a high genetic and morphological heterogeneity, inhabiting a seasonally stratified, herring (Clupea harengus Linnaeus, 1758) rich ecosystem. The DVM of copepods is a widespread advantageous behaviour, although with several trade-offs. At the expense of time spent in the food-richer surface layer, copepods avoid visual predators (planktivorous fish) by descending to greater depths, thereby decreasing their mortality. Being a part of the food web, copepods themselves serve as a source of nutrients with specific elemental contents. In the present study, we observed differences both in DVM and elemental content between the developmental stages of the studied species. The majority (57-89%) of nauplii and 1st to 3rd copepodids were found near the thermocline during daytime, whereas at night they were detected above the thermocline. The 5th stage copepodids and adults displayed evident nocturnal ascent, when most (>90%) individuals moved above 15 m depth. During daytime, they tended to disperse throughout the water column. Carbon (C%) and nitrogen (N%) in dry weight of E. affinis increased with ontogenetic development, reaching the highest values in 4th to 5th copepodids and adults. Adult males showed higher values of C% and N%, as well as an increased C : N molar ratio, compared to adult non-ovigerous females. The amount of time spent at the food-richer surface layer appeared to be related to N% in E. affinis.

scholarly journals Evidence from the past: exploitation as cause of commercial extinction of autumn-spawning herring in the Gulf of Riga, Baltic Sea

2018 ◽  
Vol 75 (7) ◽  
pp. 2476-2487
Author(s):  
Brian R MacKenzie ◽  
Henn Ojaveer
Keyword(s):  
Baltic Sea ◽  
Biological Data ◽  
Clupea Harengus ◽  
Marine Ecology ◽  
Resource Base ◽  
Fishery Resource ◽  
Animal Populations ◽  
Gulf Of Riga ◽  
Commercially Important ◽  
The Baltic

Abstract Historical marine ecology has shown that many exploited animal populations declined before their abundance was quantified by scientists. This situation applies for autumn-spawning herring (Clupea harengus) in the Baltic Sea. This stock used to be the dominant spawning group of herring in the early decades of the 1900s and supported several commercially important fisheries, including in the Gulf of Riga (GoR). However, the GoR stock declined during the 1960–1970s and has not recovered. Neither the former biomass nor reasons for its decline are known. Here, we recover and analyse historical fishery and biological data and conduct population development simulations to evaluate the hypothesis that exploitation may have been sufficient to lead the stock towards commercial extinction. We found that the estimated exploitation pattern, including exploitation of juveniles, was unsustainable and led to stock decline. The pattern of exploitation of this stock was consistent with that which caused collapses of other herring stocks, which have since recovered. If autumn-spawning herring in the GoR recovers, our findings indicate that this stock could support sustainable annual yields of ∼4000 t and diversify the fishery resource base, which is presently restricted to a relatively small number of species for essentially local coastal inhabitants.

scholarly journals Survey of Presence of Non-Indigenous Eurytemora Carolleeae in the Gulf of Riga (Baltic Sea) Five Years After its First Discovery

2018 ◽  
Vol 72 (4) ◽  
pp. 230-235
Author(s):  
Labuce Astra ◽  
Ikauniece Anda ◽  
Strāķe Solvita ◽  
Souissi Anissa
Keyword(s):  
Baltic Sea ◽  
Calanoid Copepod ◽  
Reproduction Rate ◽  
Indigenous Species ◽  
Physiological Plasticity ◽  
Eurytemora Affinis ◽  
Male And Female ◽  
Key Species ◽  
Gulf Of Riga ◽  
Non Indigenous Species

Abstract In the brackish ecosystem of the Gulf of Riga, the calanoid copepod Eurytemora affinis is a key species, but recently a new non-indigenous species Eurytemora carolleeae was discovered in the region. In the present study, we aimed to validate the presence of E. carolleeae in the southern part of the Gulf of Riga five years after its first discovery. The study area is the closest region to the Rīga harbour — the main source of non-indigenous species arrival in the Gulf. Recent studies have predicted the possible potential of E. carolleeae invasion due to its physiological plasticity. Male and female specimens of Eurytemora were collected in spring, summer, and autumn of 2013, and analysed based on three morphological indicators. Despite the higher reproduction rate of E. carolleeae, this intrusive species does not seem to have succeeded in establishing during the five-year period after its first discovery in the Gulf of Riga, and hence does not present a threat to the native E. affinis population in the study area.

scholarly journals Nash equilibrium can resolve conflicting maximum sustainable yields in multi-species fisheries management

2016 ◽  
Vol 74 (1) ◽  
pp. 78-90 ◽  
Author(s):  
Niclas Norrström ◽  
Michele Casini ◽  
Noél M. A. Holmgren
Keyword(s):  
Nash Equilibrium ◽  
Baltic Sea ◽  
Fisheries Management ◽  
Clupea Harengus ◽  
The Other ◽  
The Baltic Sea ◽  
Trade Offs ◽  
Spawning Stock ◽  
Point Solution ◽  
The Baltic

The current fisheries management goals set by the European Commission states that fish stocks should be harvested to deliver maximum sustainable yields (MSY) and simultaneously, management should take ecosystem considerations into account. This creates unsolved trade-offs for the management of the stocks. We suggest a definition of a multi-species-MSY (MS-MSY) where no alternative fishing mortality (F) can increase yield (long term) for any ecologically interacting stock, given that the other stocks are fished at constant efforts (Fs). Such a MS-MSY can be solved through the game theoretic concept of a Nash equilibrium and here we explore two solutions to this conflict in the Baltic Sea. We maximize the sustainable yield of each stock under two constraints: first, we harvest the other stocks at a fixed F (FNE); second, we keep the spawning stock biomasses of the other stocks fixed [biomass Nash equilibrium (BNE)]. As a case study, we have developed a multi-species interaction stochastic operative model (MSI-SOM), which contains a SOM for each of the three dominant species of the Baltic Sea, the predator cod (Gadus morhua), and its prey herring (Clupea harengus), and sprat (Sprattus sprattus). For our Baltic Sea case, MS-MSYs exist under both the FNE and the BNE, but there is no guarantee that point solutions exists. We found that the prey species’ spawning stock biomasses are additive in the cod growth function, which allowed for a point solution in BNE. In the FNE, the herring MSY was found to be relatively insensitive to the other species’ fishing mortalities (F), which facilitated a point solution. The MSY targets of the BNE and the FNE differ slightly where the BNE gives higher predator yields and lower prey yields.

Trophic decoupling of mesozooplankton production and the pelagic planktivores sprat Sprattus sprattus and herring Clupea harengus in the Central Baltic Sea

2018 ◽  
Vol 592 ◽  
pp. 181-196 ◽  
Author(s):  
M Bernreuther ◽  
J Peters ◽  
C Möllmann ◽  
J Renz ◽  
J Dutz ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Clupea Harengus ◽  
Sprattus Sprattus

scholarly journals Adult body growth and reproductive investment vary markedly within and across Atlantic and Pacific herring: a meta-analysis and review of 26 stocks

2021 ◽  
Author(s):  
Thassya C. dos Santos Schmidt ◽  
Doug E. Hay ◽  
Svein Sundby ◽  
Jennifer A. Devine ◽  
Guðmundur J. Óskarsson ◽  
...  
Keyword(s):  
Egg Size ◽  
Meta Analysis ◽  
Reproductive Investment ◽  
Body Growth ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Atlantic Herring ◽  
Additional Information ◽  
Trade Offs ◽  
Investment In Reproduction

AbstractLife-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.

scholarly journals Elemental Inventory in Fish Otoliths Reflects Natal Origin of Atlantic Herring (Clupea harengus) From Baltic Sea Juvenile Areas

2019 ◽  
Vol 6 ◽  
Author(s):  
Dorothee Moll ◽  
Paul Kotterba ◽  
Klaus Peter Jochum ◽  
Lena von Nordheim ◽  
Patrick Polte
Keyword(s):  
Baltic Sea ◽  
Clupea Harengus ◽  
Atlantic Herring ◽  
Natal Origin ◽  
Fish Otoliths

Modeling Relationships between Baltic Sea Herring (Clupea harengus) Biology and Contaminant Concentrations Using Multivariate Data Analysis

2010 ◽  
Vol 44 (23) ◽  
pp. 9018-9023 ◽  
Author(s):  
Katrin Lundstedt-Enkel ◽  
Rickard Bjerselius ◽  
Lillemor Asplund ◽  
Kerstin Nylund ◽  
Yang Liu ◽  
...  
Keyword(s):  
Data Analysis ◽  
Baltic Sea ◽  
Multivariate Data Analysis ◽  
Multivariate Data ◽  
Clupea Harengus
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