Tag Archives: Update

Update on Research

From last week:

  • Paper needing revision for Journal of Fish Biology. I received quite general reviews, in some places very general comments with very little attention to results. Since the modeling is quite complex and the statistical analyses quite detailed, I would have appreciated much more attention to those parts. The paper deals with the consequences of massive mortality events , think floods, wildfires, rain-on-snow, on evolution of traits (in particular body growth and age at sexual maturity) and on population dynamics of affected fish populations. The results are interesting, there are consequences on the evolution of traits, albeit of small magnitude with respect to simulations where traits are not allowed to evolve, but very little consequences on population dynamics and risk of extinction. So, there is evolution, but in term of consequences at the higher level (population), nothing to write home about. This has consequences also when thinking about fishery-induced evolution of traits. One of the reviewers is asking for more generality (you never go wrong asking for more generality, yes we are talking about floods, but you need to write that you are also talking about oxygen crisis, poison, oil spills, divine intervention, basically everything that can generate a strong response. I believe floods are not general enough, since they unfortunately kill people, kill fish and other animals, cause billion of dollars of damage every year all over the world etc.). Other requests are connections to conservation measures (not much unfortunately, floods are just a common occurrence, especially in mountain streams) and other stuff on the "minor" side.
  • Received request for moderate revision of a paper submitted to Hydrobiologia. Doable, I should stress more the novelty of my approach and clarify the use of water velocity as a predictor for suitability of habitat for the growth of a clam of great commercial value. It is an area of research I am not actively pursuing, but I enjoy giving answers to very applied questions. I have a wide range of interests, and how to solve "real" problems is one of them. However, I do not know I will continue working in this area or not. I'd enjoy write another paper on the use of ensembles to better predict the distribution of species of commercial value. The idea is there and the algorithm has been partially developed, the problem is as always time and focus. This is the abstract of the paper:

    "Species distribution models are still scarcely applied for the estimation of potential productivity of aquaculture species. Here, we show how a simple species distribution model can be used for the rapid estimation of commercial yield potential and for the identification of suitable sites for Tapes philippinarum in two North Adriatic lagoons. We use a two-part species distribution model with sediment type, hydrodynamism, dissolved oxygen and salinity as predictors. The first component of the model uses logistic regression to identify the areas in which clams occurs or not, while the second component estimates the potential yield (kg m-2) by applying a  weighted geometric mean  of suitability values. We estimate the weights  of the geometric mean with site-specific yield data  by a constrained linear regression, validate the model on independent data and then apply the two-part conditional model to the whole surfaces of the two lagoons. The model provides a good prediction of the yield data in the validation dataset (R2adj = 0.86). The calibration and application of a simple HSM  model can be a useful tool for objectively identifying the most suitable sites for aquaculture activities and support the sustainable management of farming activities in the Po river delta."

    I plan to send the ms back to Hydrobiologia in a couple of weeks. I need also to redraw a figure and I will test my skills with Adobe Illustrator, just for fun.

  • I am almost ready to submit with my colleagues the manuscript on the estimation of parameters of parameter-rich von Bertalanffy growth curve functions using the Empirical Bayes method as implemented in ADMB. Lots of code, lots of figures, lots of testing. I learned a lot, but it took a lot of time. The problem now is setting the introduction properly. It is not easy, as the ms has the aim of providing both a "novel" method and new biological insights on the growth process. The methods has been applied to a couple of populations of marble trout, and it generated some very interesting results on the shared (think about year class effects) and individual (genetic + stochasticity, like finding a good spot for foraging) determinants of the observed variation in growth trajectories. In about a week at most, I will submit the paper to American Naturalist.
  • I submitted almost a couple a months ago to American Naturalist my solo paper on the evolution of a quantitative trait following extreme events, and since the 24th of September is waiting for American Naturalist's Assistant Editor and Editor decision. I am waiting too.