Oceanographic and Bathymetric Features as the Target for Pelagic MPA Design: A Case Study on the Cape of Gata

Abstract

The Cape of Gata region (southeast Spain) allocates the thermo-haline Almeria–Oran front (AOF), which separates two biogeographical zones, with a very irregular bathymetry, consisting of two canyons and seamounts in an area of 100 × 100 km. An interdisciplinary oceanographic sampling strategy allowed us to solve mesoscale processes including current–bathymetry interactions. Subsurface fertilizing processes and elevated chlorophyll a concentrations were found at the front, seamount, and submarine canyons, turning an apparently oligotrophic area into a rich one. According to a horizontal tracking simulation, the deep chlorophyll maximum (DCM) at the front is located above the pycnocline and travels fast offshore, transporting productivity from the fertilization process quickly from the region. The DCM at the seamount, in contrast, develops below the pycnocline and remains for almost three weeks in this area. In spite of the coastal marine protected areas (MPAs), a high surface nitrate concentration plume with its origin in a small coastal area without any protection was detected. Local circulation patterns and bathymetry–current interactions provide elevated productivity in surface water which is vertically connected to deep-sea fauna via the daily vertical migration of zooplankton, suggesting elevated biodiversity on the seamount and canyons of the area studied. Based on these results, and considering the presence of coastal MPAs and a Coastal Area Management Program, future studies on benthic fauna, an enlargement of coastal MPAs, and a transboundary land–deep-sea management program are suggested.

Surface Chlorophyll-A Fronts in the Yellow and Bohai Seas Based on Satellite Data

“…As shown in Figures 4 and 7, although SST fronts were strong in winter, t vertical mixing and light-limitation inhibited the formation of chl-a fronts [32,4 discussed in Section 4.1. Therefore, there was no distinct links between the chl-a f SST front in winter.…”

“…An oceanic front is a narrow zone of intensified horizontal gradients of water properties (i.e., physical, chemical, or biological) that separates different water masses (e.g., [1,2]). Fronts are a common marine phenomenon occurring in coastal, shelf, and pelagic waters, and play an important role in hydrodynamics and the transport of heat, salt, and nutrients, influencing ecological processes, sedimentation, and ocean-atmosphere interaction (e.g., [2][3][4][5]).…”

Biophysical Processes Determining the Connectivity of the Alboran Sea Fish Populations

“…no-take Marine Protected Areas, MPAs) is a key tool used in marine conservation to enhance ecosystem resilience and reduce the decline of fisheries resources. The effectiveness of a MPA (and network of MPAs) is highly dependent on careful consideration of connectivity processes in their design (Muñoz et al, 2018). In the Alboran Sea MPAs, east-west and along-shore connectivity are, in addition to mesoscale and topographic-induced processes, of higher relevance compared to potential north-south connectivity.…”

“…MPAs were initially thought as the main conservation mechanisms for coastal ecosystems, while their importance as a management measure to recover fish stocks at the continental shelf and slope is increasing (e.g. European hake, Muñoz et al 2018). However, one of the main challenges with MPAs networks design is the general mismatch between fisheries dependency and the larval supply provided by MPAs (Andrello et al, 2017), mainly associated with local communities highly dependent on small-scale fisheries.…”