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Boston, MA, United States

While single factor diet studies appear to be of simple design, the space constraints in aquaculture caused by the need to filter the aqueous media often create constraints on the implementation of the experimental design. A number of papers have been published in which the experimental design and subsequent analysis is incorrect. This paper reviews the principles of experimental design as it related to single factor diet evaluation studies in aquaculture. By adhering to simple design principles to ensure that experimental units are independent, the data generated by future experiments will be of high quality and results more robust. Source

Fiedler G.C.,University of Maryland University College | Rhyne A.L.,Edgerton Research Laboratory | Rhyne A.L.,Roger Williams University | Segawa R.,Tokyo Metroplitan University | And 2 more authors.
BMC Evolutionary Biology | Year: 2010

Background. The hippolytid genus Lysmata is characterized by simultaneous hermaphroditism, a very rare sexual system among Decapoda. Specialized cleaning behavior is reported in a few pair-living species; these life history traits vary within the genus. Unfortunately, the systematics of Lysmata and the Hippolytidae itself are in contention, making it difficult to examine these taxa for trends in life history traits. A phylogeny of Lysmata and related taxa is needed, to clarify their evolutionary relationships and the origin of their unique sexual pattern. In this study, we present a molecular phylogenetic analysis among species of Lysmata, related genera, and several putative hippolytids. The analysis is based upon DNA sequences of two genes, 16S mtDNA and nuclear 28S rRNA. Phylogenetic trees were estimated using Bayesian Inference, Maximum Likelihood, and Maximum Parsimony. Results. Phylogenetic analysis of 29 species of Lysmata, eight genera of Hippolytidae and two genera of Barbouriidae based on a single (16S, 28S) and combined gene approach (16S+28S) indicates that three groups of Lysmata differentiate according to antennular morphology: (1) Lysmata, having a multi-segmented accessory branch, (2) Hippolysmata (prior to Chace 1972), with a one-segmented accessory branch, and (3) a third group of Lysmata outliers, with one-segmented unguiform accessory branch, and close affinity to the genera Exhippolysmata and Lysmatella. The monophyly of the clade bearing a multi-segmented accessory branch is robust. Within the short accessory branch clade, species with specialized cleaning behaviors form a monophyletic clade, however, the integrity of the clade was sensitive to alignment criteria. Other hippolytid and barbouriid genera used in the analysis are basal to these three groups, including one displaying simultaneous hermaphroditism (Parhippolyte). The two barbouriid species occur in a separate clade, but among hippolytid taxa. Conclusions. The data support the historical morphological division of Lysmata into clades based on accessory branch morphology. The position of the "cleaner" shrimps, indicates that specialized cleaning behavior is a derived trait. The topologies of the cladograms support the monophyly of the barbouriids, but do not support their elevation to familial status. Taxa ancestral to the genus Lysmata display simultaneous hermaphroditism, suggesting that this life history trait evolved outside the genus Lysmata. © 2010 Fiedler et al; licensee BioMed Central Ltd. Source

Fortune S.M.E.,University of British Columbia | Trites A.W.,University of British Columbia | Perryman W.L.,Southwest Fisheries Science Center | Moore M.J.,Woods Hole Oceanographic Institution | And 2 more authors.
Journal of Mammalogy | Year: 2012

Body growth of North Atlantic right whales (Eubalaena glacialis) was described from measurements of known-age live and dead individuals to gain insights into the nutritional needs and life-history strategies of this endangered species. Body lengths from 154 individuals revealed that calves more than doubled in size and attained three-fourths of asymptotic adult size by the time they had weaned at 12 months. Calves gained on average ∼1.7 cm and ∼34 kg per day while nursing during this extremely rapid growth phase. Mean predicted lengths and body mass were 4.2 m and 1.1 metric tons (mt) at birth, 10.3 m and 13.5 mt at weaning, and 13.6 m and 29.6 mt when fully grown. Growth of right whales was best described using a 2-phased Gompertz growth model and could not be fit using any of the single continuous growth models commonly used for other mammals. Rapid growth during dependency may minimize the risk of predation and maximize calf survival. Rapid calf growth also may maximize development of the mouth and baleen to optimize foraging efficiency of juveniles at the time of weaning, as well as improve reproductive fitness by reducing the age at which sexual maturity is attained. However, transferring the amount of energy needed to support the rapid postnatal growth of North Atlantic right whales may ultimately affect the intervals between pregnancies (>3 years) of mature females. © 2012 American Society of Mammalogists. Source

Storai T.,Centro Of Educazione Ambientale E Alla Sostenibilita Laguna Of Nora | Zinzula L.,Centro Of Educazione Ambientale E Alla Sostenibilita Laguna Of Nora | Repetto S.,Localita Piana Nord | Zuffa M.,Museo L. Donini | And 2 more authors.
Fisheries Research | Year: 2011

The species composition and extent of large elasmobranch bycatch in the Sardinian tuna trap fisheries have received minimal attention in the primary literature. The Sardinian Large Elasmobranch Database (SLED), a non-governmental project, contains records from direct observations, fishing industry sources and reviews from the literature regarding the extent and composition of large elasmobranch bycatch from the only six tuna traps at six fishing sites (Saline; Capo Testa; Carloforte; Portoscuso; Calasetta; and Portopaglia) from the period of 1990 to 2009. During this time period, 42 bycatch events were documented that were comprised of the incidental capture of 15 Mobulid rays and 27 large sharks representing ten species and seven families (23% of the total elasmobranch species previously reported in Sardinian waters). Even though the low number of collective elasmobranchs captured (n= 42) in this study does not pose a conservation concern several bycatch species considered rare and/or depleted in this region were among the species observed. Mobula mobular was the most abundant elasmobranch species caught, with Alopias vulpinus the most commonly caught shark species. There were differences in the catch per unit effort between the six sites with the highest CPUE occurring in Saline, Carloforte and Porto Paglia. Although the sheer volume and conservation impact of traditional tuna traps on large elasmobranchs is exceeded by other fishing gears in Mediterranean waters, small scale (long term) bycatch monitoring programs are vital when evaluating the presence, biodiversity and conservation of elasmobranchs in previously unstudied areas. © 2011 Elsevier B.V. Source

Rotjan R.D.,Tufts University | Rotjan R.D.,Edgerton Research Laboratory | Dimond J.L.,Western Washington University
Journal of Experimental Marine Biology and Ecology | Year: 2010

A detailed understanding of the dual role of parrotfish as both key herbivores and potentially important corallivores is essential to the study of coral health and reef trophodynamics. Some Caribbean parrotfish regularly consume live coral, and discriminate both among coral species and among colonies within a particular species. While they prefer Montastraea spp. corals, which are dominant Caribbean reef builders, causes of selective and persistent grazing of certain colonies remain unknown. We manipulated coral exposure to parrotfish grazing through a long-term cage exclusion experiment in Belize, comparing initially grazed vs. intact (non-grazed) Montastraea spp. colonies. We measured nutrition-related characteristics (C:N ratio, %C, and %N) as well as defensive characteristics (nematocyst density and skeletal hardness) to determine if any of these variables accurately predicted parrotfish grazing. There were substantial reductions in coral nutritional quality (C:N) associated with parrotfish grazing, although these changes appear to be a consequence rather than a cause of parrotfish selectivity. Likewise, nematocyst densities were suppressed in grazed corals, also likely a result of chronic grazing stress. We found no intraspecific differences in skeletal hardness related to grazing. These results provide further demonstration of the physiological consequences of grazing, but the cause of preferential grazing by parrotfishes on certain Montastraea spp. colonies still requires further investigation. © 2010 Elsevier B.V. All rights reserved. Source

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