An updated checklist of marine copepoda from Peninsular Malaysia with notes on their functional traits and distributional records

An up-to-date checklist of marine zooplankton copepods from the water of Peninsular Malaysia is presented, there are 235 species of copepods which consists of 89 genera and 44 families. Extensive list of bibliographical references with synonymy, detailed information on their functional groups, and distributional data are provided for each species. The checklist is based on taxonomic and ecological literature until 28 May 2020. Calanoida recorded the most diverse order with 101 species in total, followed by Harpacticoida with 70 species and 61 species from Cyclopoida. As for Canuelloida, Monstrilloida and Siphonostomatoida all recorded with 1 species respectively. There are 192 species of copepod recorded along the west coast (Malacca Strait) and 123 species on the east coast (South China Sea). Endemicity at species level attains 1% for the whole Peninsular Malaysian coast, with 2 genera restricted to the east coast (Kensakia parva and Brachiella malayensis) and one genus to the west coast (Labidocera jaafari). There are six dominant species that can be found along the coast of Peninsular Malaysia (Acartia erythraea, Acartia pacifica, Bestiolina similis, Euterpina acutifrons, Microsetella norvegica, Paracalanus aculeatus, Oithona nana, Oithona simplex and Temora discaudata).

Effect of temperature on population growth of copepod, Euterpina acutifrons

This study was aimed at determining the optimum temperature for culturing the copepod, Euterpina acutifrons. The trial was conducted for 10 days in chambers at temperatures of 25⁰C, 27⁰C, 29⁰C and 31⁰C. Ten adult individuals of the copepod were randomly collected and placed into three replicate experimental flasks for each treatment. Throughout the trial, the salinity, light intensity, and photoperiod were maintained at 30 ±2psu, 100molm-2s-1 and 12:12 light-dark cycle, respectively. The copepods were fed with 80,000cell/ml Isochrysis sp. daily. At the end of the trial, the total numbers of E. acutifrons nauplii, copepodites and adults were determined and counted using Sedgwick-Rafter. The highest population was found at 27⁰C with mean total population of 800±100 individuals from an initial of 10 individuals. This was followed by those reared at 25⁰C and 29⁰C where the population counts were 700±100 individuals and 367±115 individuals, respectively. At the 31⁰C, all the copepod specimens were found dead on day 5th. Statistical analysis showed that the temperature had a significant effect (P<0.05) on the population growth of the copepod. The population of nauplii was higher in lower temperature (25⁰C) set compared to the one at higher temperature (29⁰C). However, the copepodite number was greater at 27⁰C. Growth of the copepod was highest at 27⁰C (0.438K) followed by sets at 25⁰C (0.425K) and 29⁰C (0.361K). Based on the results of this analysis, it is suggested to culture copepod at temperature 25⁰C for nauplii production and 27⁰C for producing more copepodites.

Caracterização da fauna e flora associada ao sistema de maricultura de macroalgas desenvolvido na praia de Pitangui, Extremo/RN

A maricultura da macroalga Gracilaria birdae está sendo desenvolvida de forma experimental na praia de Pitangui, município de Extremoz, RN, com a colocação de balsas flutuantes como estruturas de cultivo a aproximadamente de 200m da linha da praia em maré baixa. O presente trabalho objetivou realizar um levantamento preliminar das comunidades da microflora e da fauna acompanhante no cultivo da macroalga Gracilaria birdae, situado na região costeiro marinha de Pitangui, Extremoz/RN. O experimento foi realizado através de coletas sistemáticas no entorno das balsas flutuantes de cultivo da macroalga Gracilaria birdae e zona de arrebentação da praia de Pitangui. As amostras planctônicas foram obtidas com uso de redes de plâncton com malha de 20 e 68 µm coletadas à superfície, ao redor de uma balsa de cultivo recém-instalada com 9m de extensão. O material planctônico coletado foi fixado em solução de formol a 4% e identificado em microscópio óptico, com auxílio de chaves de identificação do plâncton marinho. A ictiofauna foi coletada com o uso de uma rede de arrasto do tipo “picaré”, com dimensões de 20m de comprimento, 1,5 m de altura e 5 mm de malha entre nós. A comunidade fitoplânctonica foi composta pelos gêneros Bellerochea sp., Odontella sp., Striatella sp., Coscinodiscus sp., Fragilaria sp., Hemidiscus, sp. Rhabdonema sp., Triceratium sp., Campylodiscus sp., Chaetoceros sp e Asterionella sp. Já a comunidade zooplanctônica apresentou: Foraminifera, Copepoda: Oithona sp e Corycaeus sp.; Euterpina acutifrons; Parvocalanus crassirotris, Paracalanus quasimodo e Acartia lilljeborgi; Larva Cifonauta (Bryozoa) e Larva de Bivalve (Mollusca). A ictiofauna capturada compreendeu um total de 333 indivíduos, dentre os quais se identificou representantes de sete ordens, 15 famílias e 25 espécies. As ordens identificadas foram Perciformes (56%), Clupeiformes (12%), Pleuronectiformes (12%), Siluriformes (8%), Albuliformes (4%), Beloniformes (4%) e Tetraodontiformes (4%). Essas análises preliminares auxiliarão em estudos posteriores relacionados à análise de impactos à diversidade e riqueza do plâncton decorrentes do cultivo da macroalga Gracilaria birdae, em sistema de cultivo do tipo balsa, além de registros da ictiofauna para zona de arrebentação da praia de Pitangui.

Copepod assemblages as a bioindicator of environmental quality in three coastal areas under contrasted anthropogenic inputs (Gulf of Gabes, Tunisia)

The study of copepod assemblages indicated the presence of 22 species and 12 families in the southern coast of Sfax, 20 species and 13 families in the northern coast and 14 species and 8 families in the Ghannouch area, with a dominance of Oithonidae (79, 51 and 43% in the southern, northern and Ghannouch coasts, respectively). The relative abundance and the richness diversity of Oithonidae were found to be the most relevant indicators of anthropogenic pollution. Oithona nana, Euterpina acutifrons and Acartia clausi differed significantly in abundance between these three areas under differing degrees of pollution. The study of the structure, composition and density of the copepod fauna showed that the southern coast was a pollution-resistant ecosystem (H′ = 1.49 ± 0.33 bits ind−1; 22 species; density = 51.375 ± 4.340 × 103 ind m−3) followed by Ghannouch area (H′ = 1.74 ± 0.28 bits ind−1; 15 species; density = 11.979 ± 5.651 × 103 ind m−3) and the northern coast, considered as a restored area (H′ = 1.95 ± 0.26 bits ind−1; 21 species; density = 6.516 ± 4.304 × 103 ind m−3). The three ecosystems can thus be classified according to their degree of resistance to the anthropogenic inputs based on the results of the physico-chemical parameters and the species diversity as follows: southern coast > Ghannouch area > northern coast.

Observations on the laboratory culture of the harpacticoid copepod Euterpina acutifrons (Dana, 1847) using different diets

Hatching success, nauplii production, maturation and survival of the harpacticoid copepod Euterpina acutifrons (Dana, 1847) fed on mono/mixed culture of Isochrysis galbana, Tetraselmis gracilis, Chaetoceros calcitrans and Chlorella marina were studied. The time taken for E. acutifrons to mature was the lowest with a diet of I. galbana followed by C. calcitrans. Percentage of survival was highest with a mixed diet of 75% I. galbana and 25% C. calcitrans (84%) followed by T. gracilis (68%). The study also revealed that both feed type and concentration played significant role in production and survival of E. acutifrons. Mixed diet of I.galbana and C. calcitrans showed maximum adult production followed by a diet of T.gracilis. The mean values of all the three stages of the copepod viz., adults, ovigerous females and copepodite-nauplii were found much greater in the treatment with replacement of the culture medium and feed. Mass culture using different organic feeds was also carried out and it was found that mean growth in terms of adult stage production was found to be higher when fed with rice bran followed by groundnut oil cake (GOC) and the least in cow dung treatment. In rice bran treatment, copepodites showed higher production rate when compared to the other two feeds. Mean growth in terms of nauplii production was also higher in rice bran fed group followed by GOC fed group and the least in cow dung treatment.

KELIMPAHAN ZOOPLANKTON DAN BIOMASSA IKAN TERI (Stolephorus spp.) PADA BAGAN DI PERAIRAN KWATISORE TELUK CENDERAWASIH PAPUA (Abundance of Zooplankton and Biomass of Anchovy (Stolephorus spp.) of Liftnet at Kwatisore Bay, Cendrawasih Gulf, Papua)

ABSTRACT<br /><br />Millions of organisms can be found in the Cenderawasih Gulf National Park area, especially in the waters of the Kwatisore Bay, Nabire and has been well-known to almost all over the world. Large zooplankton is an important food for migrated fish larvae and all kinds of fish including anchovies. Anchovy is the food of large and small pelagic fish groups. Groups of fish that use plankton as food were included anchovy. The main catch product of lift net at the Kwatisore bay is anchovy (Stolephorus spp.). This study aims to assess the level of availability of anchovy in relation to the abundance of zooplankton as food and to analyze the influence of anchovy fishing activities with lift net fishing gear. The results were obtained 51 species of zooplankton, which consists of 44 types holoplankton and 7 types of meroplankton. There were 17 species of zooplankton were found in the stomach of anchovy with the subgroup dominated by copepods (73.51 %). Among 17 species of zooplankton there 2 types that were found in all four sampling periods, namely Calanus sp. 2 and Euterpina acutifrons. There is a relationship between the abundance of individual zooplankton in the waters of the anchovy biomass and also between the abundance of zooplankton and biomass of anchovy.<br /><br />Keywords: abundance of zooplankton, biomass of anchovy, lift net at Kwatisore<br />-------<br /><br />ABSTRAK<br /><br />Jutaan organisme dapat ditemukan dalam kawasan Taman Nasional Teluk Cenderawasih khususnya di perairan Kwatisore, Nabire dan telah terkenal sampai hampir ke seluruh dunia. Zooplankton berukuran besar merupakan makanan penting bagi ikan-ikan yang bermigrasi dan larva semua jenis ikan termasuk didalamnya ikan teri. Ikan teri merupakan makanan dari kelompok ikan pelagis besar dan kecil. Kelompok ikan-ikan yang banyak memanfaatkan plankton dari kelompok ikan pelagis kecil diantaranya ikan teri. Hasil tangkapan utama bagan penangkap ikan pelagis kecil di perairan Kwatisore ialah jenis teri (Stolephorus sp.). Tujuan penelitian ini adalah untuk mengkaji tingkat ketersediaan ikan teri dalam kaitannya dengan kelimpahan zooplankton sebagai makanannya serta menganalisis pengaruh dari aktivitas penangkapan ikan teri dengan alat tangkap bagan. Secara keseluruhan dari seluruh stasiun dalam setiap periode sampling, diperoleh 51 jenis zooplankton yang terdiri atas 44 jenis holoplankton dan 7 jenis meroplankton. Terdapat 17 jenis zooplankton yang ditemukan dalam lambung ikan teri dengan didominasi oleh Sub-grup Copepoda (73,51%). Diantara ke-17 jenis zooplankton tersebut terdapat 2 jenis yang ditemukan pada keempat periode sampling yaitu Calanus Sp.2 dan Euterpina acutifrons. Hasil analisis regresi linier antara biomassa ikan teri hasil tangkapan bagan dan kelimpahan maupun antara biomassa ikan teri hasil tangkapan bagan dan jumlah jenis zooplankton menunjukkan adanya korelasi positif.<br /><br />Kata kunci: kelimpahan zooplankton, biomassa ikan teri, bagan di Kwatisore

COMPORTAMIENTO ALIMENTARIO DE LA LARVA DEL HUACHINANGO DEL PACÍFICO Lutjanus peru (NICHOLS & MURPHY, 1922) (PERCOIDEI: LUTJANIDAE) AL INICIO DE LA ALIMENTACIÓN EXÓGENA

El comportamiento alimentario de larvas del huachinango del Pacífico fue estudiado bajo condiciones controladas, con énfasis especial durante el inicio de la alimentación exógena (al tercer día después de la eclosión). Durante un periodo de cinco minutos fueron observadas de manera individual diez larvas de L. peru, antes y después de ser alimentadas con rotíferos (Brachionus rotundiformis) y nauplios de copépodos (Euterpina acutifrons) en densidades de 5 presas/ml. Para describir parte del comportamiento relacionado con el evento de alimentación se registró el número de veces que las larvas adoptaron una “postura” de ataque, así como el número de ataques por larva a los diferentes tipos presa. Se observó que previo al suministro de alimento, las larvas despliegan tres tipos de conducta: nado, reposo, e impulso rápido. Una vez que fue suministrado el alimento, el patrón de conducta de las larvas cambió, independientemente del tipo de presa. La frecuencia de nado incrementó pero los desplazamientos fueron más cortos y pausas más frecuentes. El periodo de reposo de las larvas disminuyó significativamente y se observaron dos patrones de acción modal asociados directamente al proceso de alimentación: 1) postura sigmoide (“S”), adoptada posterior a la detección de una presa, 2) ataque, evento durante el cual la larva se impulsa espontáneamente en dirección de la presa, independientemente de si se logra o no la captura del alimento. Menos del 50 % de las larvas observadas desplegaron una postura de ataque y el número promedio de ataques por larva durante el tiempo de observación fue menor a 1.5, independientemente del tipo de presa. Los resultados son similares a los reportados para otras larvas de peces durante el inicio de la alimentación exógena y sugieren que los nauplios de copépodos son una presa adecuada durante la primera alimentación de las larvas de L. peru. Feeding behaviour of the Pacific red snapper Lutjanus peru (Nichols & Murphy, 1922) (Percoidei: Lutjanidae) larvae at the onset of exogenous feeding The behaviour of the Pacific red snapper Lutjanus peru larvae during the onset of exogenous feeding at day 3 after hatching at 26º C was studied. Ten larvae were directly observed during 5 min each before and after the addition of feed. Rotifers (Brachionus rotundiformis) and copepod nauplii (Euterpina acutifrons) were used as live feed at a density of 5 prey/ml. Larval behavior was described before and after prey addition. Also, the number of larvae that displayed an attack posture and the number of attacks per larvae during the observation period were recorded. Before prey addition, the larvae displayed three types of conduct: swimming, resting and fast impulse. This behavioral pattern changed with the presence of feed, regardless of prey type. The swimming conduct increased duration but changed to a short distance and frequent pauses. The resting conduct reduced its duration and two new modal action patterns associated to feeding were present: “S” posture after prey detection and the attack which consisted in a direct larval strike towards the prey and may include prey capture. Less than 50% of the observed larvae displayed the attack posture and the mean number of attacks per larvae was less than 1.5 during the observation period regardless of prey type. Results are similar to the reported for other species during the onset of exogenous feeding and suggest that copepod nauplii may be a more suitable prey during first feeding of L. peru.

The epizoic marine diatom Sceptronema orientale (Licmophoraceae, Licmophorales): epitypification and emendation of specific and generic descriptions

Sceptronema orientale was found epizoic on the harpacticoid copepod Euterpina acutifrons (Dana) collected from several locations along Bahía Anegada, Province of Buenos Aires, Argentina. Material was examined with light and scanning electron microscopy and new data about the morphology of the chloroplast and ultrastructural details of the girdle, valves, apical slit fields and rimoportulae pattern were obtained. Based on this new knowledge the descriptions of the species and of the monotypic genus Sceptronema are emended. Considering that in the protologue three pictures were designated as iconotype, the material from Ría del Jabalí is chosen as an epitype to serve as the interpretative type of Sceptronema orientale. A comparison with the morphologically similar genera Licmophora and Gato was conducted and the inclusion of Sceptronema in the Family Licmophoraceae, Order Licmophorales is proposed.