Abstract Habitat information from the fjordic environments of the Chilean Patagonia is sparse, la... more Abstract Habitat information from the fjordic environments of the Chilean Patagonia is sparse, largely due to the region’s inaccessibility and lack of baseline studies from most areas. Here we present the results of a preliminary mapping study in Comau Fjord. The fjord is located within the Los Lagos region of Chile and is 30 km long and up to 10 km wide. This study is primarily based around the Huinay Scientific Field Station. Since vessels equipped with a multibeam echo sounder are unavailable in this region, an autonomous underwater vehicle (AUV) was utilized for these surveys. The AUV survey data can provide the basic information to develop habitat suitability modeling and, with repeat surveys, measure the spatiotemporal variability in benthic communities, including the impacts of any anthropogenic activity (from aquaculture or shellfish harvesting in the fjord). Habitat maps were produced at two sites within Comau Fjord: Huinay Bay and Cross Huinay, applying the Teledyne Gavia AUV which uses a 500 kHz GeoSwath+ sonar. A total of 16 habitats were identified from the combined analysis of sidescan sonar, bathymetry, and seabed images. The habitats were graded as poor and were assessed as declining over the last 5 years.
Acoustic methods are routinely used to provide broad scale information on the geographical distri... more Acoustic methods are routinely used to provide broad scale information on the geographical distribution of benthic marine habitats and sedimentary environments. Although single-frequency multibeam echosounder surveys have dominated seabed characterisation for decades, multifrequency approaches are now gaining favour in order to capture different frequency responses from the same seabed type. The aim of this study is to develop a robust modelling framework for testing the potential application and value of multifrequency (30, 95, and 300 kHz) multibeam backscatter responses to characterize sediments’ grain size in an area with strong geomorphological gradients and benthic ecological variability. We fit a generalized linear model on a multibeam backscatter and its derivatives to examine the explanatory power of single-frequency and multifrequency models with respect to the mean sediment grain size obtained from the grab samples. A strong and statistically significant (p < 0.05) cor...
Fisher's knowledge offers a valuable source of information to run parallel to observed data a... more Fisher's knowledge offers a valuable source of information to run parallel to observed data and fill gaps in our scientific knowledge. In this study we demonstrate how fishers' knowledge of historical fishing effort was incorporated into an Ecopath with Ecosim (EwE) model of the Irish Sea to fill the significant gap in scientific knowledge prior to 2003. The Irish Sea model was fitted and results compared using fishing effort time-series based on: (i) scientific knowledge, (ii) fishers' knowledge, (iii) adjusted fishers' knowledge, and (iv) a combination of (i) and (iii), termed “hybrid knowledge.” The hybrid model produced the best overall statistical fit, capturing the biomass trends of commercially important stocks. Importantly, the hybrid model also replicated the increase in landings of groups such as “crabs & lobsters” and “epifauna” which were poorly simulated in scenario (i). Incorporating environmental drivers and adjusting vulnerabilities in the foraging ar...
Abstract Habitat information from the fjordic environments of the Chilean Patagonia is sparse, la... more Abstract Habitat information from the fjordic environments of the Chilean Patagonia is sparse, largely due to the region’s inaccessibility and lack of baseline studies from most areas. Here we present the results of a preliminary mapping study in Comau Fjord. The fjord is located within the Los Lagos region of Chile and is 30 km long and up to 10 km wide. This study is primarily based around the Huinay Scientific Field Station. Since vessels equipped with a multibeam echo sounder are unavailable in this region, an autonomous underwater vehicle (AUV) was utilized for these surveys. The AUV survey data can provide the basic information to develop habitat suitability modeling and, with repeat surveys, measure the spatiotemporal variability in benthic communities, including the impacts of any anthropogenic activity (from aquaculture or shellfish harvesting in the fjord). Habitat maps were produced at two sites within Comau Fjord: Huinay Bay and Cross Huinay, applying the Teledyne Gavia AUV which uses a 500 kHz GeoSwath+ sonar. A total of 16 habitats were identified from the combined analysis of sidescan sonar, bathymetry, and seabed images. The habitats were graded as poor and were assessed as declining over the last 5 years.
Acoustic methods are routinely used to provide broad scale information on the geographical distri... more Acoustic methods are routinely used to provide broad scale information on the geographical distribution of benthic marine habitats and sedimentary environments. Although single-frequency multibeam echosounder surveys have dominated seabed characterisation for decades, multifrequency approaches are now gaining favour in order to capture different frequency responses from the same seabed type. The aim of this study is to develop a robust modelling framework for testing the potential application and value of multifrequency (30, 95, and 300 kHz) multibeam backscatter responses to characterize sediments’ grain size in an area with strong geomorphological gradients and benthic ecological variability. We fit a generalized linear model on a multibeam backscatter and its derivatives to examine the explanatory power of single-frequency and multifrequency models with respect to the mean sediment grain size obtained from the grab samples. A strong and statistically significant (p < 0.05) cor...
Fisher's knowledge offers a valuable source of information to run parallel to observed data a... more Fisher's knowledge offers a valuable source of information to run parallel to observed data and fill gaps in our scientific knowledge. In this study we demonstrate how fishers' knowledge of historical fishing effort was incorporated into an Ecopath with Ecosim (EwE) model of the Irish Sea to fill the significant gap in scientific knowledge prior to 2003. The Irish Sea model was fitted and results compared using fishing effort time-series based on: (i) scientific knowledge, (ii) fishers' knowledge, (iii) adjusted fishers' knowledge, and (iv) a combination of (i) and (iii), termed “hybrid knowledge.” The hybrid model produced the best overall statistical fit, capturing the biomass trends of commercially important stocks. Importantly, the hybrid model also replicated the increase in landings of groups such as “crabs & lobsters” and “epifauna” which were poorly simulated in scenario (i). Incorporating environmental drivers and adjusting vulnerabilities in the foraging ar...
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Papers by Clive Fox