Using remote sensing indicators to investigate the association of landings with fronts: Application to the Alboran Sea (western Mediterranean Sea)

Abstract

This study examined links between the variability of coastal front features and composition of fishery landings. Satellite‐derived sea surface temperature data allowed the detection of thermal fronts and calculation of front metrics that account for gradient, persistency, and vicinity. Landings data were clustered by functional group (according to habitat use, size, morphology), and trophic level (TL). Three independent time series analyses, based on two different classes of statistical methodologies, were carried out: (i) correlation analysis performed on species aggregated by functional groups, and (ii) compositional analysis performed on the top five species landed and on species aggregated by trophic level. Analyses were carried out for the Moroccan coast of the Alboran Sea (western Mediterranean Sea). Results of the proposed type of application were discussed with respect to their potential for improving scientific knowledge and management of fisheries in data‐poor areas. Pelagic landings were associated with front indicators in two‐thirds of tested cases. The results demonstrated a markedly different association between landings and front features in the Nador fishing zone, relative to M'diq and Al Hoceima. Improved performance of the front gradient and persistence indicator was detected, with respect to the front gradient only for flatfish and demersal landings. Compositional data regression outlined a different role for Sardina pilchardus and Trachurus trachurus in the Al Hoceima and M'diq landings, and in the latter case the dominance of these two species in the landings seemed to respond to the front density indicator. A decreasing trend in TL > 3.5 landings was detected with increasing front distance.

Oceanographic drivers of marine mammal and seabird habitat-use across shelf-seas: A guide to key features and recommendations for future research and conservation management

“…blue whale Balaenoptera musculus, fin whale Balaenoptera physalus and humpback whale; Doniol-Valcroze et al, 2007;Dalla Rosa et al, 2012). Piscivores, such as black-legged kittiwake, common dolphin Delphinus delphis, common guillemot, Magellanic penguin Spheniscus magellanicus and northern gannet, also frequently forage at tidal-mixing fronts (Kinder et al, 1983;Durazo et al, 1998;Goold, 1998;Scales et al, 2014b;Cox et al, 2016, likely because the aggregating effects of these features on plankton predictably attract high densities of forage and pelagic fish (Hansen et al, 2001;Alemany et al, 2009;Brigolin et al, 2018). Across the southeastern Bering Sea, individuals present at these features have been directly linked to high density patches of fish prey (Decker and Hunt, 1996;Kokubun et al, 2008), where capture rates were increased (Vlietstra et al, 2005).…”

Remote Sensing of Ocean Fronts in Marine Ecology and Fisheries

“…The most challenging problem is how to combine such multiple diverse characteristics as those enumerated above. The multispectral composite frontal map analysis developed by Peter Miller seems to be the most promising (Miller, 2004(Miller, , 2009Miller et al, 2015a;Brigolin et al, 2018;Suberg et al, 2019). Entropic texture-edge detection for image segmentation.…”

Bayesian longitudinal models for exploring European sardine fishing in the Mediterranean Sea

“…At regional level, strong declines in sardine landings have been reported in different Mediterranean areas [11]. Causes of these recent declines have been related to high fishing impact, competition between pelagic organisms or ecosystem effects [12,13,14].…”