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1

Implications of an extensive salt water barrage on the distribution of black clam in a tropical estuarine system, Southwest coast of India

Nagarathinam Arunpandi, Retnamma Jyothibabu, Loganathan Jagadeesan, Singaram Parthasarathi, Madam Savitha Mohanan Kannampally, Jose Albin Konnakkamannil, Subramanian Pandiyarajan Rethinam

Oceanologia

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2021

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No. 63 (3)

343--355

EN

Based on a monthly field sampling over a year in the Kochi backwaters (KBW), this study presents the larval ecology of black clam and discusses how an extensive saltwater barrage [Thannermukkom barrage (TB)] impacted the natural black clam resource distribution. Spatial variations in salinity were found minimal during the Southwest Monsoon (June-September) due to the predominance of the freshwater associated with heavy monsoonal rainfall. Conversely, significant spatial changes in salinity were evident during the Pre-Southwest Monsoon (March-May) and Post-Southwest Monsoon (October-February). Monthly sampling exercises revealed that the black clam stock in the KBW breeds throughout the year, as their larvae were found (8 indiv. m-3 -494 indiv. m-3) in all the locations. This observation is the modification of the traditional belief that black clam in the KBW breeds only twice a year. Mesohaline condition (salinity 5-18) is the most conducive for peak spawning and larval production. There were two peaks of larval production in the KBW over a year, mainly associated with the prevalence of the optimum salinity conditions on different spatial scales. The closing of the TB after the Southwest Monsoon (September) causes shrinkage of the area of the oligohaline and mesohaline conditions, the most conducive environment for the peak spawning and larval production of black clam in the KBW. This study presents a clear case of how human alterations of the natural environment impact valuable biological resources, which may apply to many similar aquatic ecosystems across the globe.

2

Distribution and abundance of larvae of Palaemon elegans (Decapoda) in the southern Baltic Sea

Dziaduch D.

Biuletyn Instytutu Morskiego w Gdańsku

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2016

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Vol. 31, No. 1

141--145

EN

The assessment of the appearance of non-indigenous species residing in benthic habitats are primarily based on knowledge obtained from their adult stage. However, most of benthic organisms have a planktonic larval stage during their early developmental phase and such a trait is believed to be behind their efficient large-scale spread. The prawn Palaemon elegans invaded into the western part of the Baltic Sea in the 1990s and by 2011 the species had colonized almost the whole sea. Currently, P. elegans has become the most common prawn species inhabiting coastal and open sea areas. The aim of this preliminary survey is to examine spatial distribution, abundance and dispersal ability of the larvae of P. elegans. Material for the studies was collected from the open waters of the southern Baltic Sea (the Gdańsk and Bornholm Basins and the Słupsk Furrow) in summers 2007 and 2008. Larvae (zoeal stages) and also postlarval stages of P. elegans were common in the whole study area and their densities were highest in the Bornholm Basin. Their maximum abundance reached up to 500 ind. · 1000 m-3 in August 2007. In the Słupsk Furrow and the Gdańsk Basin these prawns were found in much lower numbers (about 10 ind. · 1000 m-3). The current study indicates that the dispersal of the larvae of P. elegans with the water currents is one plausible mechanism of the large scale spread of this invasive species to the south-eastern coast of the Baltic Sea as well as, the study confirmed, that the new prawn has high reproductive potential.

PL

Kolonizowanie siedlisk bentosowych przez gatunki obce stwierdza się przede wszystkim po obecności ich form dorosłych. Większość organizmów bentosowych posiada w swoim cyklu życiowym postać larwalną i to na tym etapie rozwoju następuje efektywne i rozległe rozprzestrzenianie się gatunków obcych. Krewetka Palaemon elegans pojawiła się w zachodniej części Bałtyku w latach 90. XX wieku i do 2011 r. skolonizowała prawie całe morze. Obecnie, P. elegans jest najbardziej powszechnym gatunkiem krewetki zasiedlającym przybrzeżne i otwarte wody Bałtyku. Niniejsze badania wstępne mają na celu przedstawienie rozkładu przestrzennego, liczebności oraz możliwości rozprzestrzeniania się larw P. elegans . Materiał do badań zebrano z wód otwartych południowego Bałtyku (Basen Bornholmski, Rynna Słupska i Basen Gdański) latem 2007 i 2008 r. Larwy (stadia zoea) oraz postlarwy P. elegans były powszechne w całym rejonie badań, jednak najliczniej występowały w Basenie Bornholmskim. Ich maksymalna liczebność wyniosła 500 osob. · 1000 m-3 w sierpniu 2007 r. Krewetki te odnotowano również w Rynnie Słupskiej i Basenie Gdańskim, jednak w dużo niższej liczbie, około 10 osob. · 1000 m-3. Niniejsza praca potwierdziła, że rozprzestrzenianie się larw P. elegans na wielką skalę wraz z prądami morskimi ku południowo-wschodnim wybrzeżom Bałtyku oraz wysoki potencjał rozrodczy krewetki jest jednym ze sposobów kolonizacji Bałtyku przez ten inwazyjny gatunek.

3

Trace metal concentrations in free-ranger, tube-dweller chironomid larvae and a weakly polluted fluvial sediment

Grzybkowska M., Dukowska M., Michałowicz J., Leszczyńska J.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 4

445--455

EN

The objective of this study was to analyze macroinvertebrate assemblages dominated by Chironomidae (Diptera) and to assess the protective nature of these midges’ larval tubes against trace metals in the weakly polluted Bzura River. This low order lowland river flows through the Łódź City Municipal Area and is supplied by a large amount of organic matter from ecotones and a polluted roadside. Determination of metal content in sediments and chironomid tissue and tubes was conducted using atomic absorption spectroscopy. Our study has shown that the composition of chironomid assemblages was not determined by trace metals but rather by high organic enrichment, which caused the dominance of two species representing the same trophic group − gathering collectors − but differing in behavior. One of them belongs to free-rangers (Prodiamesa olivacea), while the other (Chironomus riparius) to tube-dweller larvae. Although the accumulation of certain trace metals in the tubes was found, the larvae of both types of behavior had a similar concentration of metals in their tissues, which proves effective metal detoxification in these insects.

4

Location and development of larvae of Contracaecum rudolphii Hartwich, 1964 (Nematoda: Anisakidae) in experimentally infected asps Leuciscus aspius (Linnaeus, 1758) (Pisces: Cyprinidae)

Dziekońska-Rynko J., Rokicki J., Mierzejewska K., Wziątek B., Bielecki A.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

296--301

EN

Laboratory-reproduced and bred asps were experimentally infected with Contracaecum rudolphii larvae, either directly or with previously infected copepods. In the fish exposed to larval infection, the intensity and prevalence of infection were noticeably higher than in the group exposed to copepods. The course of larvae development was similar in both groups. In the larvae measuring ca. 1000 μm in length, the gastrointestinal tract with a developed ventriculus, ventricular appendix and intestinal caecum was clearly visible. The mouth was surrounded by three lips. Over the 10-week experimental period, slightly-coiled larvae surrounded with a thin theca but no encysted larvae were found in the fish exposed to larvae. On the other hand, spirally-stranded and encysted larvae were observed after the 7th week in the fish exposed to infected copepods. The results demonstrated that in the experimentally infected asps, the intensity and prevalence of infection as well as the location of the larvae in a fish depended on the type of invasive material applied.

5

Effect of vegetation and management on occurrence of larvae and adults of generalist Maniola jurtina L. (Lepidoptera) in meadow habitats

Kulfan J., Strbova E., Zach P.

Polish Journal of Ecology

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2012

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Vol. 60, nr 3

601-609

EN

Larvae and adults of some generalist insect species co-occur in identical habitats whereas adults and larvae of other generalist species do not co-occur and occupy different habitats. The Meadow brown, Maniola jurtina (L.) (Lepidoptera: Nymphalidae), is common and widely distributed in Europe where it is considered a habitat generalist. As knowledge about the occurrence of the larvae of the Meadow brown is scarce (different and more difficult methods are needed to collect larvae compared to adults) a complex assessment of the life strategy of this generalist is limited. We addressed here the question as to whether the adults and larvae of the Meadow brown co-occurred in the same habitats and how they depended on the type of grassland vegetation and habitat management. We expected co-occurrence of adults and larvae and similar effects of habitat management on them. We selected four habitat types belonging to the alliance Arrhenatherion elatioris W. Koch 1926, which form mosaic patterns in the rural landscape of central Slovakia: (1) extensive meadows mown once a year, (2) extensive meadows mown twice a year, (3) abandoned meadows, and (4) ecotones between deciduous forests and meadows mown once a year. Adults were counted in each habitat on seven transects 50 m long (in seven replicates) during the summer of 2003, 2004 and 2005. Larvae were collected in each habitat on 10 transects 50 m long (ten replicates) by sweeping vegetation (60 sweepings per transect) at night in May 2005 and 2006. Both adults and larvae occurred in all the mentioned types of habitats. A high abundance of adults and larvae was recorded in extensive meadows mown once a year and in ecotones. The lowest abundance of adults and larvae was found in abandoned meadows. The differences between abandoned meadows and ecotones (in the case of adults) and between abandoned meadows and extensive meadows mown once a year (in the case of larvae) were significant in all study years (P <0.05; multiple comparisons, K-W ANOVA). In the abandoned meadows the number of adults and larvae (median) was approximately 2 to 5 and 5 to 25 times lower than in the preferred habitats, respectively. Maximum numbers of both adults and larvae per single recording/sampling date were obtained in extensive meadows mown once a year; that is 185 adults in a transect 350 m long and 4 m wide and 267 larvae in the transect 500 m long (600 sweepings). Hence, similar to adults, larvae tend to be habitat generalists. Our results have confirmed the "advantageous" life strategy of M. jurtina which enables the species to adapt to a wide range of habitats, including those under strong pressure from humans. Comparing management practices in the study habitats, meadows which are mowed once a year were the most appropriate alternative for this species.

6

Impact of prey field variability on early cod larval survival: a sensitivity study of a Baltic cod Individual-based Model

Schmidt J.O., Hinrichsen H-H.

Oceanologia

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2008

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No. 50 (2)

205-220

EN

Existing coupled biophysical models for Baltic larval cod drift, growth and survival use idealised constructed mean prey fields of nauplius distributions. These simulations revealed the best feeding conditions for Baltic cod larvae longer than 6 mm. For shorter, first feeding larvae (between 4.5 and 6 mm) pronounced differences in growth and survival were observed, which depend on food availability and to a lesser degree on ambient temperature. We performed runs with an Individual-based Model (IBM) for Baltic cod larvae in order to demonstrate how natural variability in prey abundance influences the survival success of first feeding larvae. In the Baltic, this larval stage lives mainly between 20 and 40 m depth and feeds exclusively on the nauplii of different calanoid copepods (Acartia spp., Pseudocalanus acuspes, Temora longicornis and Centropages hamatus). Prey data obtained from vertically stratified samples in the Bornholm Basin (Baltic Sea) in 2001 and 2002 indicate a strong variability at spatial and temporal scales. We calculated larval survival and growth in relation to natural variation of prey fields, i.e. species-specific nauplius abundance. The results of the model runs yielded larval survival rates from 60 to 100% if the mean size of nauplii species was taken and lower survival if prey consisted of early nauplius stages only.

7

Combined effects of lead ions and UV radiation on general met abolism in common frog Rana temporaria Linnaeus, 1758 Larvae

Formicki G., Stawarz R., Zamachowski W.

Chemia i Inżynieria Ekologiczna

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2006

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Vol. 13, nr 1-2

23-27

EN

General metabolism and lead accumulalion was studied in common frog tad-poles irradiated with UV (UV-A of 0.24 kJ . m-2, UV-B of 2.7 kJ . m-2) during lead poisoning (1 mg/dm3 Pb2+) and during recovery after lead poiso-ning. General melabolism of larvae during lead poisoning ranged between 0.061 +- 0.004 and 0.079 +- 0.016 mg O2/g . h-1 and the differences between experimental groups were insignificant. Significanl differences occurred after the 24, 48 and 72 hours of recovery period after the Pb2+ poisoning. General metabolism of tadpoles exposed lo UV during recovery period after lead poisoning was increasing, after initial drop (0.059 +- 0.010 mg 02/g. h-1), reaching the highesl level of 0.192 +- 0.028 mg O2/g . h-1 after 72 h. The level of accumulated lead ranged from 0.305 +- 0.156 to 0.521 +- 0.263 mg/g d.m. UV did not influence significanlly on lead accumulation and removal.

PL

Zbadano metabolizm ogólny i poziom skumulowanego ołowiu u larw żaby trawnej naświetlanych promieniowaniem UV (UV-A - 0.24 kJ . m-2, UV-B - 2.7 kJ . m-2) w czasie zatruwania ołowiem (1 mg/dm3 Pb2+) i w okresie od-truwania. Larwy w czasie zatruwania ołowiem zużywały od 0.061 +- 0.004 do 0.079 +- 0.016 mg O2/g . h-1. Różnice pomiędzy poszczególnymi grupami nie były statystycznie istotne. Znaczące różnice zaobserwowano po 24, 48 i 72 godzinach odtruwania. Poziom metabolizmu ogólnego larw eksponowanych na UV w czasie odtruwania początkowo się obniżył (0.059 +- 0.010 mg O2/g . h-1), a następnie wzrósł osiągając największe wartości po 72 godzinach od-truwania (0.192 +- 0.028 mg O2/g . h-1). Badane larwy skumulowały od 0.305 +- 0.156 do 0.521 +- 0.263 mg/g s.m. ołowiu. Nie stwierdzono znaczącego wpływu UV na kumulację i usuwanie jonów ołowiu z organizmu badanych larw.

8

Influence of composting of diseased leaves of common horse-chestnut (Aesculus hippocastanum L.) on survivability of larvae and pupae of Cameraria ohridella (Deschka & Dimić)

Dzięgielewska M., Kiepas-Kokot A., Kaup G.

Chemia i Inżynieria Ekologiczna

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2005

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Vol. 12, nr 4

377-382

EN

The results of research and observations on survivability of larvae and pupae of Cameraria ohridella in a compost pile set up in the period of late autumn were presented. The obtained results have shown insufficient temperature of compost mass for pupae dying and the protective role of high moisture to help pupae preserve life. In comparison with the wintering of pupae under treecrowns, the obtained results have revealed benefits of composting conducted even in unfavourable ambient conditions (low temperature). Comparative results for leaves stored in plastic bags have confirmed a considerable role of law moisture of wintering environment in pupa dying. The necessity for removing leaves bas been confirmed, their composting, however, ought to begin in the spring period.

PL

Przedstawiono wyniki badań i obserwacji nad przeżywalnością larw i poczwarek szrotówka kasztanowcowiaczka w pryzmie kompostowej, założonej w okresie późnej jesieni. Uzyskane wyniki świadczą o niewystarczającej dla zamierania poczwarek temperaturze kompostowanej masy i ochronnej roli dużej wilgotności dla zachowania żywotności poczwarek. Uzyskane wyniki w porównaniu do zimowania poczwarek pod koroną drzew na powierzchni ziemi świadczą na korzyść kompostowania, prowadzonego nawet w niekorzystnych warunkach otoczenia (niska temperatura). Wyniki porównawcze dla liści przechowywanych w workach foliowych świadczą o znaczącej roli małego uwilgotnienia środowiska zimowania w zamieraniu poczwarek. Potwierdzono konieczność uprzątania liści, ale ich kompostowanie powinno rozpoczynać się w okresie wiosennym. Zimowanie natomiast powinno być prowadzone przy jak najniższej wilgotności liści.

9

Anisakis simplex (Rud., 1809) (Nematoda: Anisakidae): growth and morphometry of larvae from spring spawning herring (Clupea harengus membras L.) in the Vistula lagoon and adjacent areas of the Baltic Sea

Shukhgalter O.

Oceanological Studies

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2002

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Vol. 31, No. 1-2

67-73

EN

Third-stage A. simplex larvae are described infesting baltic herring in the Vistula Lagoon and adjacent areas of the Baltic Sea (ICES-subdivisions 26). Morphometric measurements and peculiarities of allometric growth of A. simplex larvae are similar to those found as larvae of fishes in other regions, range size was wider. Growth of A. simplex larvae during spawning migration of their hosts was noted. High infestation (up to 375 specimens per fish) and the wide size range of larvae (8.0-30.0 mm) confirms that the third-stage A. simplex larvae stay alive in their hosts and increase over time.