Composição centesimal, colesterol e maturação ovariana do Acetes marinus Omori, 1975 coletado no Baixo Tocantins

A espécie Acetes marinus Omori, 1975, possui total aproveitamento alimentar constituindo-se em uma espécie de grande importância nutritiva para a população regional onde ocorre, porém, é muito pouco estudada. Visando contribuir com um melhor aproveitamento deste recurso foram realizadas coletas mensais de A. marinus durantes os meses de janeiro de 2006 a junho de 2007, em duas praias, próximas da cidade de Cametá, no baixo Tocantins. Foram determinadas a composição centesimal (%) e o teor de colesterol (mg/100g) relacionado aos parâmetros ambientais: pH, temperatura e material em suspensão da sub-superfície da água. A caracterização do desenvolvimento ovariano, baseado nas modificações macro e microscópicas. Para essas duas praias o pH médio anual foi de 7,52 ± 0,71, a temperatura foi de 26,57°C ± 1,26, e o material em suspensão foi de 73mg/L ± 65,53. Para a composição centesimal do A. marinus obteve-se: 87,1 % ± 1,1- umidade; 9,8% ±1,3-cinzas; 71% ± 1,8-proteínas; 5,4% ± 2,9-lipídios; 13,7% ± 2,6- carboidratos; 387,6% ± 13,2 Kcal-valor calórico. O teor de colesterol foi de 374,87mg/100g ± 207,08. Foi revelado um grande potencial nutricional, principalmente protéico, desta espécie, porém esta é rica em colesterol. E para o desenvolvimento ovariano foram descritos três estágios de maturação, baseados em quatro diferentes tipos de ovócitos.

Biodiversidade e variação espaço-temporal da abundância das populações de camarões e estrutura populacional de Farfantepenaeus subtilis (Pérez-Farfante, 1967) (Penaeidae) em um estuário do litoral amazônico brasileiro

Este estudo investigou a biodiversidade e a distribuição espaço-temporal da abundância das populações de camarões e descreveu a estrutura populacional de Farfantepenaeus subtilis em um estuário amazônico. Os camarões foram coletados mensalmente de agosto de 2006 a julho de 2007 nos períodos chuvoso (janeiro a junho) e seco (julho a dezembro) com arrasto-de-fundo e arrasto-de-praia nos setores Médio-Superior (MS), Médio (M) e Inferior (I). Em cada setor dois locais foram amostrados, nos quais dois arrastos de fundo de cinco minutos cada e, três arrastos praiais de 150 m² cada um foram realizados. As variáveis: temperatura, pH e salinidade da água e granulometria e matéria orgânica do sedimento foram analisadas. Para cada camarão foram anotados os Comprimentos Total (CT) e do Cefalotórax (CC), peso total, sexo e estádio de maturação gonadal. A salinidade diferiu significativamente entre os setores I e MS (p<0,05) e o M apresentou baixo teor de matéria orgânica. Em todos os setores os grãos arenosos foram predominantes no substrato, destacando-se a areia fina no setor M. Foram coletados 11.939 camarões, distribuídos em doze espécies e seis famílias. Palaemonidae e Penaeidae tiveram maior riqueza com cinco e três espécies, respectivamente. Penaeidae, Sergestidae e Palaemonidae apresentaram maior abundância, com Xiphopenaeus kroyeri, F. subtilis, Acetes marinus e Nematopalaemon schmitti, contribuindo com 43, 31, 21 e 1,3% do total capturado, respectivamente. As espécies F. subtilis, X. kroyeri e Litopenaeus schmitti contribuíram com 97% da biomassa total. A densidade e a biomassa de F. subtilis diferiram entre o chuvoso e seco (p<0,05), sendo maior no chuvoso. No chuvoso, a densidade de X. kroyeri foi mais elevada nos setores M e I e no seco nos setores MS e M, com maior biomassa no I em ambos períodos sazonais. A densidade e a biomassa de A. marinus foi elevada no setor I (p<0,05). A salinidade, areia, silte e argila influenciaram significativamente a distribuição espaço-temporal da abundância dos camarões (p<0,05). O CC das fêmeas de F. subtilis foi superior aos machos com 13,7 mm e 12,8 mm, respectivamente, e diferiu em março (p<0,05). As fêmeas foram mais abundantes e a razão sexual foi de 0,8:1 com destaque para janeiro, fevereiro, maio e o total analisado (p<0,05). Camarões desenvolvidos ocorreram no chuvoso e a abundância de juvenis foi maior de janeiro a junho quando ocorre o pico mais intenso de desova em mar aberto.

Distribution of planktonic decapods with special reference to Acetes from nearshore waters of Bombay

Distribution and seasonal variation of decapod larvae were studied from 8 stations off Versova and Mahim during Nov. 1979 to Dec. 1980. Decapod larvae were encountered throughout the year contributing 7.27% of total zooplankton. Numerically, they were more to Versova (av. 1766/100 m super(3)) than Mahim (av. 970/100 m super(3)). Acetes) spp. were common along both the transects. They were represented by Acetes indicus, A. siibogae and A. erythraeus. The effect of physico-chemical parameters in the occurrence of decapod larvae is discussed.

Occurrence and abundance of Acetes shrimps in the Kutubdia channel of Bangladesh coastal water

This investigation was carried out from June ‘89 to May ‘90 and focuses on the occurrence and abundance of Acetes shrimps in the Kutubdia channel. The shrimps of the genus Acetes occurred throughout the year in the area of investigation. Acetes showed a bimodal peak in occurrence, one in late monsoon season (August - September) and other in pre-monsoon season (February - March). But the maximum number of Acetes shrimps was recorded in March (462 individuals/haul). The Acetes population of this channel was dominated by four species, Acetes erythraeus (38.50%), A. indicus (32.98%), A. chinensis (4.48%) and A. japonicus (3.32%).

Size frequency distribution and carapace length-total length relationship of Acetes chinensis in the Kutubdia channel of Bangladesh coast

The seasonal mean size distribution of A. chinensis were estimated as 29.229mm ±4.77, 25.125mm ±2.55, 25.165mm ±2.29 and 32.44mm ±3.63 for annual, monsoon, postmonsoon and pre-monsoon period, respectively. Seasonal mean carapace length distribution were estimated as 9.37mm ±1.457, 8.063mm ±0.63,8.258mm ±0.59 and 10.37mm ±l.ll3 for annual, monsoon, post-monsoon and the pre-monsoon season. The carapace length and total length relationships was found to be TL= - 1.39±3.23 CL. Linear relation was found in arithmetic and as well as logarithmic scale.

Preparation of edible powder from Jawla (Acetes sp.) prawns

Four methods were employed for the preparation of prawn (Acetes) powder in this study. The analytical characteristics and bacteriological quality of the edible powders are presented for each method.

Protein from Jawla prawn (Acetes spp.) and Squilla (Orato squilla nepa)

A simple method of isolation of protein from jawla prawn and squilla, which does not involve any chemical treatment, is reported. The method consists in blending the jawla prawn/squilla with equal quantity of water, removal of chitinous matter, heating the pulp at 112°C for 15-20 minutes and drying the precipitated protein after filtration.

Recruitment of lesser sandeel Ammodytes marinus in relation to density dependence and zooplankton composition

Recent recruitment failure of lesser sandeel Ammodytes marinus, a key prey fish in the North Sea, followed by several years of low spawning stock biomass, prompted us to investigate factors influencing the recruitment of this species. We tested 2 hypotheses that relate to ecological mechanisms of recruitment regulation in lesser sandeel: (1) a positive spawning stock–recruitment relationship is decoupled in years associated with high abundances of age-1 sandeels and (2) the survival success of early larvae depends specifically on the abundance of Calanus finmarchicus and not C. helgolandicus. The findings of the present study supported both hypotheses and resulted in a multiple linear recruitment model with pronounced predictive capabilities. The model includes interactions between age-1 abundance and spawning stock biomass, plus the effect of C. finmarchicus abundance, and it explained around 65% of the inter-annual variation in recruitment in contrast to only 12% by a traditional Ricker curve. We argue that early egg production in C. finmarchicus supports the survival of larvae, and that climate-generated shifts in the Calanus species composition lead to a mismatch in timing between food availability and the early life history of lesser sandeels.

Predatory nature of the littoral amphipod Echinogammarus marinus: gut content analysis and effects of alternative food and substrate heterogeneity

Interspecific interactions are major structuring forces in marine littoral communities; however, it is unclear which of these interactions are exhibited by many key-component species. Gut content analysis showed that the ubiquitous rocky/cobble shore amphipod Echinogammarus marinas, often ascribed as a mesograzer, consumes both algae and macroinvertebrates. Further, laboratory experiments showed that E. marinus is an active predator of such macroinvertebrates, killing and consuming the isopod Jaera nordmanni and the oligochaete Tubificoides benedii. Predatory impacts of E. marinus were not alleviated by the presence of alternative food in the form of alga discs. However, in the presence of prey, consumption of alga by E. marinus was significantly reduced. Further, survival of prey was significantly higher when substrate was provided, but predation remained significant and did not decline with further increases in substrate heterogeneity. We conclude that such amphipods can have pervasive predatory impacts on a range of species, with implications for community structure, diversity and functioning.

A PRELIMINARY ASSESSMENT OF THE DISTRIBUTION OF THE SEA LAMPREY (PETROMYZON MARINUS L.), RIVER LAMPREY (LAMPETRA FLUVIATILIS (L.)) AND BROOK LAMPREY (LAMPETRA PLANERI (BLOCH)) IN NORTHERN IRELAND

Lampreys are endangered in Europe, and European states are legally required to take measures to ensure their protection. However, there is currently little information on the distribution of the three species present in Northern Ireland. Anecdotal records of adult lampreys were collated from anglers and other sources, and a systematic electrofishing survey was undertaken to establish the distribution of lamprey ammocoetes. Lampreys were found in seven of the nine Northern Irish river catchments. Brook lampreys (Lampetra planeri (Bloch)) were widely distributed, but the two anadromous species, sea lamprey (Petromyzon marinus L.) and river lamprey (Lampetra fluviatilis (L.)), were more limited in their distribution, possibly due to barriers restricting migration.

Functional responses of the intertidal amphipod Echinogammarus marinus: effects of prey supply, model selection and habitat complexity.

The influence of predation in structuring ecological communities can be informed by examining the shape and magnitude of the functional response of predators towards prey. We derived functional responses of the ubiquitous intertidal amphipod Echinogammarus marinus towards one of its preferred prey species, the isopod Jaera nordmanni. First, we examined the form of the functional response where prey were replaced following consumption, as compared to the usual experimental design where prey density in each replicate is allowed to deplete. E. marinus exhibited Type II functional responses, i.e. inversely density-dependent predation of J. nordmanni that increased linearly with prey availability at low densities, but decreased with further prey supply. In both prey replacement and non-replacement experiments, handling times and maximum feeding rates were similar. The non-replacement design underestimated attack rates compared to when prey were replaced. We then compared the use of Holling’s disc equation (assuming constant prey density) with the more appropriate Rogers’ random predator equation (accounting for prey depletion) using the prey non-replacement data. Rogers’ equation returned significantly greater attack rates but lower maximum feeding rates, indicating that model choice has significant implications for parameter estimates. We then manipulated habitat complexity and found significantly reduced predation by the amphipod in complex as opposed to simple habitat structure. Further, the functional response changed from a Type II in simple habitats to a sigmoidal, density-dependent Type III response in complex habitats, which may impart stability on the predator−prey interaction. Enhanced habitat complexity returned significantly lower attack rates, higher handling times and lower maximum feeding rates. These findings illustrate the sensitivity of the functional response to variations in prey supply, model selection and habitat complexity and, further, that E. marinus could potentially determine the local exclusion and persistence of prey through habitat-mediated changes in its predatory functional responses.