Scyphozoan jellyfish provide short-term reproductive habitat for hyperiid amphipods in a temperate near-shore environment

Hyperiid amphipods (Order Amphipoda, Suborder Hyperiidea) are known to infest gelatinous zooplankton. However, the temporal backdrop to these associations is less clear, given that data are often gathered during discrete sampling events rather than over time. In general, hyperiids are considered to be pelagic: however, for individuals associated with metagenic jellyfishes in temperate shallow shelf seas, this may not always be the case, as the majority of their gelatinous hosts are present in the water column from spring to the onset of autumn. Here, we explored the temporal patterns of colonisation and overall duration of the association between Hyperia galba and 3 scyphozoan jellyfish species (Aurelia aurita, Cyanea capillata and C. lamarckii) in a temperate coastal system (Strangford Lough, Northern Ireland) during 2010 and 2012. Concomitantly, we used carbon and nitrogen stable isotope ratios to examine whether hyperiid infestation represented a permanent association with their host or was part of a more complex life history. We found that jellyfish were colonised by H. galba ca. 2 mo after they are first observed in the lough and that H. galba reached 100% prevalence in the different jellyfish species shortly before the medusae of each species disappeared from the water column. It is possible that some jellyfish overwintered in deeper water, prolonging the association between H. galba and their hosts. However, all the medusae sampled during the spring and early summer (whether they were newly emerged or had overwintered from the previous season) were not infected with hyperiids, suggesting that such behaviour was uncommon or that individuals had become dissociated from their host during the winter. Further evidence of temporary association came from stable isotope data, where ��13C and ��15N isotope ratios were indicative of feeding outside of their host prior to jellyfish colonisation. In combination, these findings suggest alternating habitat associations for H. galba, with the amphipods spending the majority of the year outside of the 3 scyphozoan species considered here.

Environmental selection on transcriptome-derived SNPs in a high gene flow marine fish, the Atlantic herring (Clupea harengus)

<p>High gene flow is considered the norm for most marine organisms and is expected to limit their ability to adapt to local environments. Few studies have directly compared the patterns of differentiation at neutral and selected gene loci in marine organisms. We analysed a transcriptome-derived panel of 281 SNPs in Atlantic herring (Clupea harengus), a highly migratory small pelagic fish, for elucidating neutral and selected genetic variation among populations and to identify candidate genes for environmental adaptation. We analysed 607 individuals from 18 spawning locations in the northeast Atlantic, including two temperature clines (5-12 ��C) and two salinity clines (5-35���). By combining genome scan and landscape genetic analyses, four genetically distinct groups of herring were identified: Baltic Sea, Baltic-North Sea transition area, North Sea/British Isles and North Atlantic; notably, samples exhibited divergent clustering patterns for neutral and selected loci. We found statistically strong evidence for divergent selection at 16 outlier loci on a global scale, and significant correlations with temperature and salinity at nine loci. On regional scales, we identified two outlier loci with parallel patterns across temperature clines and five loci associated with temperature in the North Sea/North Atlantic. Likewise, we found seven replicated outliers, of which five were significantly associated with low salinity across both salinity clines. Our results reveal a complex pattern of varying spatial genetic variation among outlier loci, likely reflecting adaptations to local environments. In addition to disclosing the fine scale of local adaptation in a highly vagile species, our data emphasize the need to preserve functionally important biodiversity.</p>

Biomarkers reveal the effects of hydrography on the sources and fate of marine and terrestrial organic matter in the western Irish Sea

<p>A suite of lipid biomarkers were investigated from surface sediments and particulate matter across hydrographically distinct zones associated with the western Irish Sea gyre and the seasonal bloom. The aim was to assess the variation of organic matter (OM) composition, production, distribution and fate associated with coastal and southern mixed regions and also the summer stratified region. Based on the distribution of a suite of diagnostic biomarkers, including phospholipid fatty acids, source-specific sterols, wax esters and C₂₅ highly branched isoprenoids, diatoms, dinoflagellates and green algae were identified as major contributors of marine organic matter (MOM) in this setting. The distribution of cholesterol, wax esters and C₂₀ and C₂₂ polyunsaturated fatty acids indicate that copepod grazing represents an important process for mineralising this primary production. Net tow data from 2010 revealed much greater phytoplankton and zooplankton biomass in well-mixed waters compared to stratified waters. This appears to be largely reflected in MOM input to surface sediments. Terrestrial organic matter (TOM), derived from higher plants, was identified as a major source of OM regionally, but was concentrated in proximity to major riverine input at the Boyne Estuary and Dundalk Bay. Near-bottom residual circulation and the seasonal gyre also likely play a role in the fate of TOM in the western Irish Sea.</p>

Gorgonians of the South of Portugal: biology, ecology and conservation

O papel ecol��gico das gorg��nias (Octocorallia: Alcyonacea) nos fundos marinhos rochosos �� mundialmente reconhecido. Contudo, a informa����o acerca da ecologia e biologia das esp��cies de gorg��nias nas zonas temperadas do NE Atl��ntico �� manifestamente escassa, especialmente tendo em considera����o as actuais perturba����es globais, regionais e locais. Nos fundos rochosos da costa algarvia at�� aos 30 m, verificouse que v��rias esp��cies de gorg��nias s��o abundantes e frequentes, nomeadamente Eunicella labiata, Eunicella gazella, Eunicella verrucosa, Leptogorgia lusitanica e Leptogorgia sarmentosa. As popula����es de gorg��nias s��o co-dominadas por diferentes esp��cies que apresentaram elevados ��ndices de associa����o, indicando reduzidos n��veis de competi����o entre elas. Em todo o caso, a estrutura dos povoamentos diferiu com as condi����es locais. Todas as esp��cies evidenciaram padr��es de distribui����o semelhantes ao longo do gradiente de profundidade, i.e. a abund��ncia aumenta significamente com a profundidade ap��s os 15 m. A profundidades mais baixas (at�� aos 15 m), a distribui����o das gorg��nias parece ser condicionada por factores abi��ticos e pela competi����o com algas. Com efeito, os padr��es de distribui����o espacial das esp��cies de gorg��nias na costa algarvia s��o determinados pela interac����o de press��es naturais e antropog��nicas (ex. pesca). Ainda que as col��nias de maior tamanho n��o tenham sido restritas a ��reas menos pescadas, em ��reas mais perturbadas pela pesca, a distribui����o dos tamanhos das col��nias estava maioritariamente desviada para tamanhos mais pequenos. Os efeitos das perturba����es naturais nas popula����es de gorg��nias foram evidenciados pela ocorr��ncia de padr��es demogr��ficos distintos em ��reas vizinhas sujeitas a n��veis semelhantes de press��es antropog��nicas. Estes estudos demonstraram, ainda, que os efeitos na distribui����o de frequ��ncias de tamanho das col��nias s��o dependentes das esp��cies de gorg��nias em causa: Eunicella labiata n��o parece ser afectada; Leptogorgia sarmentosa �� tendencialmente afectada por press��es antropog��nicas; Eunicella gazella e Leptogorgia lusitanica aparentam ser afectadas, quer por press��es naturais, quer por press��es antropog��nicas. Os efeitos verificados nos padr��es da distribui����o de frequ��ncias de tamanho, particularmente a tend��ncia para o desvio destas frequ��ncias para tamanhos mais pequenos em ��reas sujeitas a perturba����es, poder��o ter consequ��ncias para a biodiversidade dos fundos sublitorais rochosos na costa algarvia. Com efeito, o presente estudo apoia o paradigma geral de que os corais s��o habitats que suportam comunidades de elevada biodiversidade e abund��ncia. Num dos poucos estudos que examinam a rela����o entre as gorg��nias e as suas comunidades de invertebrados epibent��nicos, foi verificado que as gorg��nias (Eunicella gazella e Leptogorgia lusitanica) sustentam comunidades ricas (11 phyla, 181 taxa) e abundantes (7284 indiv��duos). Estas comunidades s��o dominadas por anf��podes, mas os poliquetas tiveram um grande contributo para os n��veis elevados de biodiversidade. Verificou-se, igualmente, que o tamanho da col��nia desempenha um papel fundamental na biodiversidade, na medida em que as col��nias de menor tamanho apresentaram um contributo mais baixo, comparativamente ��s m��dias e grandes. Ainda que ambas as gorg��nias partilhem a maioria das esp��cies amostradas, 11 e 18 taxa foram exclusivos de Eunicella gazella e Leptogorgia lusitanica, respectivamente (excluindo indiv��duos com presen��as ��nicas). No entanto, a maioria destes taxa eram ou pouco abundantes ou pouco frequentes. A excep����o foi a presen��a de plan��rias (Turbellaria) de colora����o branca nas col��nias de Eunicella gazella, provavelmente beneficiando do efeito de camuflagem proporcionado pelos ramos com a mesma colora����o. Com efeito, a complementaridade entre as comunidades epibent��nicas associadas a ambas as gorg��nias diminuiu quando usados os dados de presen��a/aus��ncia, sugerindo que os padr��es de biodiversidade s��o mais afectados pelas altera����es na abund��ncia relativa das esp��cies dominantes do que pela composi����o faun��stica. As comunidades de epifauna bent��nica associadas a estas gorg��nias n��o s�� apresentaram valores elevados de ��-diversidade, como de ��- diversidade, resultantes de padr��es intrincados de variabilidade na sua composi����o e estrutura. Ainda que o conjunto de esp��cies dispon��veis para coloniza����o seja, na generalidade, o mesmo para ambos os locais, cada col��nia apresenta uma parte deste conjunto. Na sua totalidade, as col��nias de gorg��nias poder��o funcionar como uma metacomunidade, mas a estrutura das comunidades associadas a cada col��nia (ex. n��mero total de esp��cies e abund��ncia) parecem depender dos atributos da col��nia, nomeadamente superf��cie dispon��vel para coloniza����o (altura, largura e ��rea), complexidade e heterogeneidade (dimens��o fractal e lacunaridade, respectivamente) e cobertura epibent��nica ���colonial��� (ex. fauna colonial e algas macrosc��picas; CEC). Numa primeira tentativa para quantificar a rela����o entre as gorg��nias e os invertebrados epibent��nicos a elas associados (em termos de abund��ncia e riqueza espec��fica), verificou-se que a natureza e a intensidade destas rela����es dependem da esp��cie hospedeira e variam para os grupos taxon��micos principais. No entanto, independentemente do grupo taxon��mico, a riqueza espec��fica e a abund��ncia est��o significativamente correlacionadas com a CEC. Com efeito, a CEC provavelmente devido a um efeito tr��fico (aumento da disponibilidade alimentar directo ou indirecto), combinado com a superf��cie dispon��vel para coloniza����o (efeito esp��cies-��rea) foram as vari��veis mais relacionadas com os padr��es de abund��ncia e riqueza espec��fica. Por outro lado, ainda que a complexidade estrutural seja frequentemente indicada como um dos factores respons��veis pela elevada diversidade e abund��ncia das comunidades bent��nicas associadas a corais, a dimens��o fractal e a lacunaridade apenas foram relevantes nas comunidades associadas a Leptogorgia lusitanica. A validade do paradigma que defende que a complexidade estrutural promove a biodiversidade poder�� ser, ent��o, dependente da escala a que se realizam os estudos. No caso das gorg��nias, o efeito da complexidade ao n��vel dos agregados de gorg��nias poder�� ser muito mais relevante do que ao n��vel da col��nia individual, refor��ando a import��ncia da sua conserva����o como um todo, por forma a preservar a diversidade de esp��cies hospedeiras, o seu tamanho e estrutura. Actividades antropog��nicas como a pesca, podem, ainda, ter efeitos negativos ao n��vel da reprodu����o de esp��cies marinhas. Analogamente ao verificado para os padr��es de distribui����o espacial das popula����es de gorg��nias na costa algarvia, a informa����o relativa �� sua reprodu����o �� igualmente escassa. Os estudos realizados em popula����es de Eunicella gazella a 16m de profundidade, demonstraram que o desenvolvimento anual das estruturas reprodutivas �� altamente sincronizado entre os sexos. A raz��o entre sexos na popula����o foi de 1.09 (F:M), encontrando-se perto da paridade. A espermatog��nese estende-se por 6 a 8 meses, enquanto que a oog��nese �� mais demorada, levando mais de um ano para que os o��citos se desenvolvam at�� estarem maduros. Antes da liberta����o dos g��metas, foi observada uma elevada fecundidade nas f��meas (27.30��13.24 o��citos p��lipo���1) e nos machos (49.30��31.14 sacos esperm��ticos p��lipo���1). Estes valores encontram-se entre os mais elevados reportados �� data para zonas temperadas. A liberta����o dos g��metas (n��o h�� evid��ncia de desenvolvimento larvar, nem �� superf��cie da col��nia, nem no seu interior) occorre em Setembro/ Outubro, ap��s um per��odo de elevada temperatura da ��gua do mar. As f��meas emitem o��citos maduros de elevadas dimens��es, retendo, todavia, os o��citos imaturos que se desenvolvem apenas na ��poca seguinte. Ainda que o efeito da pesca nas popula����es de gorg��nias da costa do Algarve seja percept��vel, ��s taxas actuais, o mergulho recreativo n��o aparenta afectar seriamente estas popula����es. Contudo, sendo uma ind��stria em expans��o e conhecendo-se a prefer��ncia de mergulhadores por ��reas rochosas naturais ricas em esp��cies bent��nicas, futuramente poder�� vir a afectar estes habitats. A monitoriza����o de mergulhadores na costa algarvia mostrou que a sua maioria (88.6 %) apresenta comportamentos que podem impactar o habitat, com uma taxa m��dia de contactos de 0.340��0.028 contactos min���1. Esta taxa foi mais elevada em mergulhadores com moderada experi��ncia e na fase inicial do mergulho (0���10 min). Os contactos com as barbatanas e m��os foram comuns, resultando, maioritariamente, na resuspens��o do sedimento, mas geralmente apresentando um impacto reduzido. Todavia, a fauna tamb��m foi afectada, quer por danos f��sicos, quer pela interac����o com os mergulhadores, e num cen��rio de expans��o significativa desta actividade, os impactos na fauna local poder��o aumentar, com consequ��ncias para os ecossistemas de fundos rochosos da costa sul de Portugal. Na sua globalidade, a informa����o recolhida nos estudos que contemplam esta tese, por ser em grande parte totalmente nova para a regi��o, espera-se que contribua para a gest��o da zona costeira do Algarve.

Argyrosomus regius (Asso, 1801) fishery and ecology in portuguese waters, with reference to its relationships to other european and african populations

Tese de doutoramento, Biologia (Biologia Marinha e Aquacultura), Universidade de Lisboa, Faculdade de Ci��ncias, 2014

Comparison of the Distribution, Abundance, and Diversity of Zooplankton in Trevor Channel and Alberni Inlet, Barkley Sound, Vancouver Island, Canada

Senior thesis written for Oceanography 444

Mapping multi-species habitat use for marine conservation planning

Tese de Doutoramento, Ci��ncias do Mar (Biologia Marinha)

Sei whale (Balaenoptera borealis) ecology and management in the North Atlantic

Tese de Doutoramento em Ci��ncias do Mar, especialidade em Ecologia Marinha.

Ecological interactions between zooplankton and photosynthetic bacteria in Crawford Lake, Ontario

The present study was carried out to test the hypothesis that photosynthetic bacteria contribute a large portion of the food of filter feeding zooplankton populations in Crawford Lake, Ontario. The temporal and spatial variations of both groups of organisms are strongly dependent on one another. 14 By using C-Iabelled photosynthetic bacteria. the ingestion and clearance rates of Daphnia pulex, ~. rosea, and Keratella spp were estimated during summer and fall of 1982. These quantitative estimations of zooplankton ingestion and clearence rates on photosynthetic bacteria comprised an original addition to the literature. Photosynthetic bacteria comprised a substantial portion of the diet of all four dominant zooplankton species. The evidence for this is based on the ingestion and clearance rates of the dominant zooplankton species. Ingestion rates of D. pulex and D. rosea ranged 5 5 -1 -1 - -- 5 - -- 5 from 8.3X10 -1 to 14.6XlO -1 cells.ind. hr and 8.1X10 to 13.9X10 cells.ind. hr ��� Their clearance rates ranged from 0.400 to 1.000 -1 -1 -1 -1 ml.ind. hr. and 0.380 to 0.930 ml.ind. hr ��� The ingestion and clearance -1 -1 -1 -1 rates of Keratella spp were 600 cell.ind. hr and 0.40 ul.ind. hr respectively. Clearance rates were inversely proportional to the concentration of food cells and directly proportional to the body size of the animals. It is believed that despite the very short reg~neration times of photosynthetic bacteria (3-8 hours) their population densities were controlled in part by the feeding rates of the dominant zooplankton in Crawford Lake. By considering the regeneration times of photosynthetic bacteria and the population clearance rates of zooplankton, it was estimated that between 16 to 52% and 11 to 35% of the PHotosynthetic bacteria were' consumed�� by Daphnia�� pulex. and Q.. rosea per day. The temporal and spatial distribution of Daphnia pulex, !.. rosea, Keratella quadrata, K. coChlearis and photosynthetic bacteria in Crawford Lake were also investigated during the period of October, 1981 to December, 1982. The photosynthetic bacteria in the lake, constituted a major food source for only those zooplankton Which tolerate anaerobic conditions. Changes in temperature and food appeared to correlate with the seasonal changes in zooplankton density. All four dominant species of zooplankton were abundant at the lake's surface (O-4m) during winter and spring and moved downwards with the thermocline as summer stratification proceeded. Photosynthetic bacteria formed a 2 m thick layer at the chemocline. The position of this photosynthetic bacterial J-ayer changed seasonally. In the summer, the bacterial plate moved upwards and following fall mixing it moved downwards. A vertical shift of O.8m (14.5 to 15.3m) was recorded during the period of June to December. The upper limit of the photosynthetic bacteria in the water column was controlled by dissolved oxygen, and sulfide concentrations While their lower limit was controlled by light intensity. A maximum bacterio- 1 chlorophyll concentration of 81 mg Bchl.l was recorded on August 9, 1981. The seasonal distribution of photosynthetic bacteria was controlledinpart' by ��theg.-"z1ai'_.Q;~.zoopl. ank:tCm;-.Qther -ciactors associated with zooplankton grazing were oxygen and sulfide concentrations.

STUDIES ON TAXONOMY, DISTRIBUTION, ECOLOGY AND REPRODUCTIVE POTENTIAL OF ROTIFERS FROM SELECTED CENTRES IN COCHIN BACKWATER SYSTEM, KERALA

The studies were conducted in nine stations with varying ecological characteristics along Cochin backwaters and adjoining canals. Many workers opined that the distribution of rotifers is cosmopolitan. The significance of rotifers as first food for early larvae was indicated by Fujita. Aquaculture is a fast growing field in fisheries sector and it is gaining more importance as the fish landings and supply are getting irregular. A consistent supply of fish/shellfish can only be achieved through aquaculture. The success of any culture activity depends on the timely production of seeds of finfishes/shellfishes. The availability of wild seed is seasonal and erratic. So, a dependable source of seed of fishes and shellfishes is possible only through large scale production in hatchery. A successful seed production activity depends on the availability of a variety of suitable live feed organisms in sufficient quantities at the proper time for use in the larval stages. As the live feeds promote high growth rates, easy digestion, assimilation and the quality of not contaminating the culture water when compared to other artificial feeds, make the culture of live feed organisms the principal means of providing food for the larvae of finfishes and shellfishes. Rotifers are considered to be an excellent and indispensable food for larvae of many finfishes and crustaceans. It (1960) was the first to culture Brachionus plicatilis for feeding marine fish larvae, and now it is being extensively used as live feed in hatcheries all over the world. They are a group of microscopic organisms coming under the Phylum Rotifera which comprises of about 2000 species. Their slow swimming habits, ability to tolerate a wide range of salinities, parthenogenetic mode of reproduction and ability to get enriched easily, make rotifers an ideal live feed organism. The major factors such as temperature, salinity and food that influence the reproductive potential and thereby the population size of rotifer, Salinity is one of the most important aspect influencing the reproductive rate of rotifers. The feed type and feed concentration play a vital role in influencing the reproductive rate of rotifers. For culture of rotifers, the commonly used micro algae belong to Chlorella, Nannochloropsis, Isochrysis and Tetraselmis. While some studies have suggested that, algal diet has little effect on reproductive rates in 1979 while using the rotifer, Brachionus plicatilis as feed for the larvae of red sea bream, Pagrus major. It is generally accepted that rotifers play a pivotal role in the successful rearing of marine fish larvae.

Comparative Studies on the Abundance of Zooplankton in the Surrounding Sea & Lagoons in the Lakshadweep

Composition and distribution of various groups and species of zooplankton at Kavaratti, Agatti and Suhelipar atolls of the Lakshadweep group of islands are reported . Higher biomass and diversity occur in the sea surrounding atolls compared to lagoons . Copepoda forms the dominant component of zooplankton . Zooplankton washed across the reef into the lagoon may be serving as food to the reef community . No fauna endemic to lagoons are encountered.

Biochemical studies on some Tropical Esturine Zooplankton Species

Percentages of protein, carbohydrate and lipid which form the major biochemical constituents of 10 species of zooplankton from Cochin backwaters were estimated . Protein invariably formed the major constituent in terms of dry weight. Carbohydrate content was in general very poor . Both protein and lipid were low for organisms with higher water content and did not show any reciprocal relationship . The results in general supported the view that protein may function as a metabolic reserve in zooplankton and that the availability of a constant supply of food may render large amount of lipid storage unnecessary in tropical zooplankton.

Algal blooms and zooplankton standing crop along the southwest coast of India

Dept. of Marine Biology, Microbiology and Biochemistry,CUSAT

Studies on the Biology, Ecology and Fishery of the sea cucumber Holathuria (hetriatyla) scabra (Jaeger) from southeast coast of India

The distribution of the holothurian H. KH.) scabra indicated its availability all along coastal areas on Palk Bay from Rameswavam to Mallipattinam and along the Gulf of Hannah coast from Pamban to Ervadi and Tuticmhin,'at 4~2O m depth.The major fishing for holmthurians was done by skin diving at all the centres. The tallu valai was operated at Tuticorin and Vedalai and trawlevs were operated at Rameswaram.The fmod of H. KN.) scabra consists of ovganic matter which contains mud, sand, shell debris, bivalves and algae. Obsehvatinns indicated the species seems to be a n0n���se1ective feeder. The assimilation efficiency from sediment to faeces indicated that the faecal pellets of H. KH.) scabra are semidigested.A multiple relationship was fitted between total length, total weight, gutted weight, gonad weight and maturity stages were found significant.The fishing season for holothurians commences from October to March along Gulf of Manner coast and from March to October along Palk Bay coast.The percentage of catches recorded by skin diving, trawlere and tallu valai were 80.04%, 10.27% and 9.69% respectively. Skin diving contributes to maximum catch.The holothurians landed all along the Gulf of Manner and Palk Bay coasts constitute 25.6% and 74.4% respectively. This showed that Palk Bay coast is more productive.