spatial modeling of fish distributions

Abstract

Fish abundance is thought to be related to environmental factors and interactions between species. Catches at locations close to each other may also be similar resulting in spatial autocorrelation. The aim of this report is to assess the relationship between fish abundance and environmental correlates, the relationship between distributions of different fish species and temporal trends in fish abundance. Data for whiting, haddock and cod fish species were collected under the North Sea-International Bottom Trawl Survey (NS-IBTS) from 1994 to 2005. Approximate full Bayesian inference was performed based on the Integrated Nested Laplace Approximation (INLA) approach. Predictions of fish catches per quarter and age class for 1994 and 2005 were done for each of the three species. Results show that there is a relationship between fish abundance and depth of the sea. Different species are more abundant at locations of different depth which varied with quarter and age class. Further to this, t