scholarly journals Biophysical modeling of larval Baltic cod (Gadus morhua) growth and survival

2002 ◽  
Vol 59 (12) ◽  
pp. 1858-1873 ◽  
Author(s):  
H.-H Hinrichsen ◽  
C Möllmann ◽  
R Voss ◽  
F W Köster ◽  
G Kornilovs

A coupled hydrodynamic–trophodynamic individual-based model of drift and feeding was utilized to analyze the intra- and inter-annual variability in growth and survival of cod (Gadus morhua) larvae in the central Baltic Sea. Highly temporally and spatially resolved simulated flow fields were used to investigate the potential drift of larval cod from the centre of spawning effort in the Bornholm Basin towards their nursery areas through temporally resolved three-dimensional idealized prey fields. Stomach content analyses of larval cod from the Bornholm Basin revealed calanoid copepod nauplii and early copepodite stages to be the preferred prey organisms. The results of the model runs indicate that larval cod changed from a nonlimited to a food-limited stage because of the strong decrease in abundance of the calanoid copepod Pseudocalanus elongatus during the last two decades. The modeling study revealed retention and dispersal from the main spawning ground to be a key process influencing larval survival. When P. elongatus was available in the prey fields, high cod larval survival rates occurred in spring and early summer. In contrast, when P. elongatus was not available, hatched larvae had only high survival probabilities later in the year or if they were transported into shallower coastal regions.

2011 ◽  
Vol 32 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Joana Ribeiro ◽  
Rui Rebelo

AbstractFor amphibians with complex life cycles, the regulation of populations may occur in each life history stage and although available data stress the importance of studying amphibian population dynamics during the larval stage, most studies so far still focus only on the adult phase, due to the difficulty to estimate larval survival under field conditions. Through a two-months capture-recapture study of 646 photo-identified tadpoles of Alytes cisternasii we aimed to estimate tadpole survival in isolated temporary stream pools – their main habitat – as well as to evaluate how pool characteristics and intraspecific competition (tadpole density) affect this parameter. Photo-identification was performed with the help of the software I3S. We used the POPAN formulation of the Jolly-Seber model to estimate survival rates and population size in 9 stream pools. Tadpole density varied from ∼1 to 40 tadpoles · m–2. Tadpole weekly survival was relatively high, varying from 75 to 99% · week–1. Among-pool differences in survival were best explained by pool depth, and not by tadpole density or other pool characteristics. The lower survival estimates were obtained for the deep pools. The very high survival estimates for some pools are an indication that this type of discrete habitat may play an important role for this species. To our knowledge, this is the first time that photo-identification is used to obtain estimates for survival and density of tadpoles.


2006 ◽  
Vol 63 (2) ◽  
pp. 285-295 ◽  
Author(s):  
Heum Gi Park ◽  
Velmurugu Puvanendran ◽  
Anne Kellett ◽  
Christopher C. Parrish ◽  
Joseph A. Brown

Abstract Recently, the nutritional requirements of marine finfish larvae have received considerable attention, and studies have shown that docosahexaenoic acid (DHA) affects the growth and survival of marine finfish larvae. We investigated the effects of different rotifer diets containing variable amounts of DHA on the growth and survival of larval Atlantic cod (Gadus morhua L.). Four different commercial rotifer enrichment formulations were used: spray-dried whole cells composed of Crypthecodinium sp. (ED1), spray-dried whole cells of Schizochytrium sp. (ED2), an oil emulsion (ED3) and ED1, and dried Chlorella at a 7:3 ratio by weight (ED4). The resultant rotifers contained a similar concentration of DHA (1.1–1.6% DW), but the level of DHA differed in proportion to EPA for each enrichment, and was designated ER1–4. Twelve 30-l aquaria were used with three replicates per treatment. Larvae were fed with rotifers from 3 to 43 days post-hatch (dph) at 4000 prey l−1. At the end of the experiment, no significant differences were found in body length and dry weight between the larvae reared on ER1 and ER2. However, larvae reared on ER3 were significantly smaller (both in length and weight) than larvae reared on ER1 and ER2. Larval survival on the ER2 treatment at 43 dph was significantly higher than on the other three treatments. Our results showed a positive effect of rotifer DHA proportions on growth and survival of cod larvae, and demonstrated that Atlantic cod larvae require a high ratio of dietary DHA to EPA.


2001 ◽  
Vol 52 (8) ◽  
pp. 1413 ◽  
Author(s):  
Phil J. James ◽  
Lennard J. Tong ◽  
Megan P. Paewai

The effects of stocking density and the presence of shelter on the growth and mortality of early juvenile spiny lobsters, Jasus edwardsii, were determined over periods of 118 and 162 days respectively. Growth in length and weight were significantly slower with increasing stocking densities from 50 to 200 m–2, but overall mortality rates were very low and exhibited no difference amongst the densities tested. Conversely, shelter appeared to help to maintain high survival rates in early juvenile lobsters but had no effect on growth throughout the experiment. For maximum growth and survival in a commercial aquaculture operation, densities of 50 to 100 m–2, and adequate shelter would be recommended for early juvenile spiny lobsters. The implications of these results are discussed in relation to aquaculture of this species.


2007 ◽  
Vol 87 (6) ◽  
pp. 1777-1784 ◽  
Author(s):  
Nicole J. de Voogd

In the present study, carried out in the Spermonde Archipelago, south Sulawesi, Indonesia, an assessment is presented of the farming potential of six sponge species (out of nine candidates considered) possessing pharmacologically promising compounds, i.e. Aaptos suberitoides, Amphimedon paraviridis, Callyspongia (Euplacella) biru, Hyrtios reticulatus, Ircinia ramosa and Pseudoceratina cf. verrucosa. A total of 350 cuttings was threaded on a polyethylene rope and attached to horizontal mooring structures at three experimental sites. Growth and survival were monitored for a period of six months and for some explants for an additional period of ten months. All cuttings were photographed at regular time intervals and growth was measured as increase in length and dry weight. With the exception of P. cf. verrucosa, survival rates were high (80–96%) during the mariculture period. Size increases were too little to be measured in A. suberitoides and P. cf. verrucosa cuttings. Significant growth was only observed for C. biru. The high growth potential and high survival rate of this sponge species suggest that it is a promising candidate for further mariculture development.


2019 ◽  
Vol 70 (4) ◽  
pp. 459
Author(s):  
D. P. Svozil ◽  
R. K. Kopf ◽  
R. J. Watts ◽  
A.O. Nicholls

Different populations of organisms can vary widely in their responses to environmental conditions and this variation is fundamental to the persistence of species. Using a common garden experiment, we examined temperature-specific growth and survival responses of larvae among populations of Murray cod (Maccullochella peelii) from four regions of the Murray–Darling Basin (MDB), Australia. Fish larvae from the four regions differed significantly in their growth and survival responses at high water temperatures ≥26°C. At 30°C, survival rates of larvae by Day 20 ranged from 0% in the Lachlan region to 82% in the southern region. Opposite to the geographical differences in survival, growth of larvae was highest in the Lachlan (14.8–15.4-mm standard length 95% CI) and lowest in the southern region (13.4–13.9-mm standard length 95% CI) at 26°C where sufficient numbers survived for comparison. Geographical differences in growth and survival responses did not follow a consistent latitudinal gradient as observed for other species, but were closely linked with previously described genetic structure. Our results suggest that the upper thermal limit of M. peelii larvae is near common river temperatures in the MDB and that maintaining functional response diversity and underlying genetic diversity will be important for ensuring the resilience of this apex predator under future climate change.


2014 ◽  
Vol 71 (9) ◽  
pp. 2515-2529 ◽  
Author(s):  
T. Kristiansen ◽  
K. W. Vollset ◽  
S. Sundby ◽  
F. Vikebø

Abstract The ability of larval fish to find food successfully after hatching is critical for their growth and survival during the early life stages. However, the feeding ecology of larval fish is strongly dependent on prevailing physical and biological conditions. Small changes in the prey distribution, turbulence, light, and ocean temperature can affect larval survival probabilities. This study combined physical and biological observations collected from Atlantic cod (Gadus morhua) spawning grounds from Lofoten, Norway, during the years 1991–1992 with an individual-based model (IBM) that is able to simulate behaviour, feeding, and growth. Observational data on the vertical distribution of larval cod revealed that they congregated at 10–25 m during the day, although the highest abundance of prey was generally in the upper 10 m. Using the behavioural component of the IBM, we analysed the mechanistic interactions between larval bioenergetics and the physical–biological environment and compared modelled with observed vertical larval cod distribution. During periods of both low and high prey densities, turbulence had a significant impact on larval cod feeding and growth rates as well as on larval vertical distribution. At low prey abundance (<5 nauplii l−1), turbulence enhanced encounter rates were very important for sustaining ingestion and growth rates for first-feeding larval cod. Our results suggest that turbulence allowed larval cod to sustain high ingestion rates even deeper in the water column, where prey densities are usually lower.


2016 ◽  
Vol 74 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Hans-Harald Hinrichsen ◽  
Christoph Petereit ◽  
Anders Nissling ◽  
Isa Wallin ◽  
Didzis Ustups ◽  
...  

A hydrodynamic model coupled with a Lagrangian particle tracking technique was utilized to simulate spatially and temporally resolved long-term environmentally related (i) size of habitat suitable for reproduction, (ii) egg/yolk-sac larval survival, (iii) separation of causes of mortality, and (iv) connectivity between spawning areas of Baltic flounder with pelagic eggs. Information on reproduction habitat requirements and mortality sources were obtained from field or laboratory studies. In our modelling study we only quantified physical processes generating heterogeneity in spatial distribution of eggs and yolk-sac larvae, as e.g. predation is not accounted for. The spatial extent of eggs and larvae represented as modelled particles is primarily determined by oxygen and salinity conditions. The reproduction habitat most suitable was determined for the Gdansk Deep, followed by the Bornholm Basin. Relatively low habitat suitability was obtained for the Arkona Basin and the Gotland Basin. The model runs also showed yolk-sac larval survival to be to a large extent affected by sedimentation. Eggs initially released in the Arkona Basin and Bornholm Basin are strongly affected by sedimentation compared with those released in the Gdansk Deep and Gotland Basin. Highest relative survival of eggs occurred in the Gdansk Deep and in the Bornholm Basin. Relatively low survival rates in the Gotland Basin were attributable to oxygen-dependent mortality. Oxygen content had almost no impact on survival in the Arkona Basin. For all spawning areas mortality caused by lethally low temperatures was only evident after severe winters. Buoyancy of eggs and yolk-sac larvae in relation to topographic features appear as a barrier for the transport of eggs and yolk-sac larvae and potentially limits the connectivity of early life stages between the different spawning areas.


BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043844
Author(s):  
Natalia Araujo ◽  
Samantha Morais ◽  
Ana Rute Costa ◽  
Raquel Braga ◽  
Ana Filipa Carneiro ◽  
...  

IntroductionProstate cancer is the most prevalent oncological disease among men in industrialised countries. Despite the high survival rates, treatments are often associated with adverse effects, including metabolic and cardiovascular complications, sexual dysfunction and, to a lesser extent, cognitive decline. This study was primarily designed to evaluate the trajectories of cognitive performance in patients with prostate cancer, and to quantify the impact of the disease and its treatments on the occurrence of cognitive decline.MethodsParticipants will be recruited from two main hospitals providing care to approximately half of the patients with prostate cancer in Northern Portugal (Portuguese Institute of Oncology of Porto and São João Hospital Centre), and will comprise a cohort of recently diagnosed patients with prostate cancer proposed for different treatment plans, including: (1) radical prostatectomy; (2) brachytherapy and/or radiotherapy; (3) radiotherapy in combination with androgen deprivation therapy and (4) androgen deprivation therapy (with or without chemotherapy). Recruitment began in February 2018 and is expected to continue until the first semester of 2021. Follow-up evaluations will be conducted at 1, 3, 5, 7 and 10 years. Sociodemographic, behavioural and clinical characteristics, anxiety and depression, health literacy, health status, quality of life, and sleep quality will be assessed. Blood pressure and anthropometrics will be measured, and a fasting blood sample will be collected. Participants’ cognitive performance will be evaluated before treatments and throughout follow-up (Montreal Cognitive Assessment and Cube Test as well as Brain on Track for remote monitoring). All participants suspected of cognitive impairment will undergo neuropsychological tests and clinical observation by a neurologist.Ethics and disseminationThe study was approved by the Ethics Committee of the hospitals involved. All participants will provide written informed consent, and study procedures will be developed to ensure data protection and confidentiality. Results will be disseminated through publication in peer-reviewed journals and presentation in scientific meetings.


2019 ◽  
Vol 47 (5) ◽  
pp. 1307-1325 ◽  
Author(s):  
Caroline Busch ◽  
Helen Wheadon

Abstract Chronic myeloid leukaemia (CML) is a paradigm of precision medicine, being one of the first cancers to be treated with targeted therapy. This has revolutionised CML therapy and patient outcome, with high survival rates. However, this now means an ever-increasing number of patients are living with the disease on life-long tyrosine kinase inhibitor (TKI) therapy, with most patients anticipated to have near normal life expectancy. Unfortunately, in a significant number of patients, TKIs are not curative. This low-level disease persistence suggests that despite a molecularly targeted therapeutic approach, there are BCR-ABL1-independent mechanisms exploited to sustain the survival of a small cell population of leukaemic stem cells (LSCs). In CML, LSCs display many features akin to haemopoietic stem cells, namely quiescence, self-renewal and the ability to produce mature progeny, this all occurs through intrinsic and extrinsic signals within the specialised microenvironment of the bone marrow (BM) niche. One important avenue of investigation in CML is how the disease highjacks the BM, thereby remodelling this microenvironment to create a niche, which enables LSC persistence and resistance to TKI treatment. In this review, we explore how changes in growth factor levels, in particular, the bone morphogenetic proteins (BMPs) and pro-inflammatory cytokines, impact on cell behaviour, extracellular matrix deposition and bone remodelling in CML. We also discuss the challenges in targeting LSCs and the potential of dual targeting using combination therapies against BMP receptors and BCR-ABL1.


2020 ◽  
Vol 9 (12) ◽  
pp. 3943
Author(s):  
João Caramês ◽  
Ana Catarina Pinto ◽  
Gonçalo Caramês ◽  
Helena Francisco ◽  
Joana Fialho ◽  
...  

This retrospective study evaluated the survival rate of short, sandblasted acid-etched surfaced implants with 6 and 8 mm lengths with at least 120 days of follow-up. Data concerning patient, implant and surgery characteristics were retrieved from clinical records. Sandblasted and acid-etched (SLA)-surfaced tissue-level 6 mm (TL6) or 8 mm (TL8) implants or bone-level tapered 8 mm (BLT8) implants were used. Absolute and relative frequency distributions were calculated for qualitative variables and mean values and standard deviations for quantitative variables. A Cox regression model was performed to verify whether type, length and/or width influence the implant survival. The cumulative implant survival rate was assessed by time-to-event analyses (Kaplan–Meier estimator). In all, 513 patients with a mean age of 58.00 ± 12.44 years received 1008 dental implants with a mean follow-up of 21.57 ± 10.77 months. Most implants (78.17%) presented a 4.1 mm diameter, and the most frequent indication was a partially edentulous arch (44.15%). The most frequent locations were the posterior mandible (53.97%) and the posterior maxilla (31.55%). No significant differences were found in survival rates between groups of type, length and width of implant with the cumulative rate being 97.7% ± 0.5%. Within the limitations of this study, the evaluated short implants are a predictable option with high survival rates during the follow-up without statistical differences between the appraised types, lengths and widths.


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