Towards spatial management of fisheries in the Gulf: benthic diversity, habitat and fish distributions from Qatari waters

Abstract

As with many other regions in the world, more complete information on the distribution of marine habitats in the Gulf is required to inform environmental policy, and spatial management of fisheries resources will require better understanding of the relationships between habitat and fish communities. Towed cameras and sediment grabs were used to investigate benthic habitats and associated epifauna, infauna and fish communities in the central Gulf, offshore from the east coast of Qatar, in water depths of between 12 and 52 m. Six different habitats were identified: (i) soft sediment habitats of mud and (ii) sand, and structured habitats of (iii) macro-algal reef, (iv) coral reef, (v) mixed reef, and (vi) oyster bed. The epibenthic community assemblage of the mud habitat was significantly different to that of sand, which in turn differed from the structured habitats of coral reef, mixed reef and oyster bed, with the macroalgal assemblage having similarities to both sand and the other structured habitats. Fish assemblages derived from video data did not differ between habitats, although certain species were only associated with particular habitats. Epibenthic diversity indices were significantly lower in mud, sand and macro-algal habitats, with no differences recorded for fish diversity. Soft sediment grab samples indicated that mud habitats had the highest benthic diversity, with Shannon-Weiner values of >4, and were more diverse than sand with values of 3.3. The study demonstrates high biodiversity in benthic habitats in the central and southwestern Gulf, which may in part be due to the absence of trawling activity in Qatari waters. There is a strong influence of depth on benthic habitat type, so that depth can be used to predict habitat distribution with a high level of accuracy. The presence of outcrops of hard substrata creates a mosaic of patchy shallow structured benthic habitat across extensive areas of the offshore seabed. Such heterogeneity, and the association of commercially exploited fish species with specific habitats, indicates that this region is well suited to a spatial approach to fisheries management.

Choosing best practices for managing impacts of trawl fishing on seabed habitats and biota

“…For example, the prohibition of trawling in Venezuela inshore in 2001 and territorial waters in 2009 led to increased catches by small‐scale fishers who supplied 70% of annual fisheries production (compared to only 6%, or 70,000 t, by trawlers in 2007). In Qatar, the number of artisanal fishers (+52%), the artisanal catch (+159%) and the size of artisanal‐class vessels increased after closure of its bottom‐trawl fishery in 1993 (Al‐Abdulrazzak, ; El Sayed, ; FAO, ; Walton et al, ). Bottom trawling was banned in favour of longlines around Madeira, the Azores and Canary Islands in 2005 to protect coral reefs, where it has been estimated that one deep‐sea bottom trawl will have an impact on cold‐water corals similar to 296–1,719 longlines (Pham et al, ).…”

“…For example, the prohibition of trawling in Venezuela inshore in 2001 and territorial waters in 2009 led to increased catches by small-scale fishers who supplied 70% of annual fisheries production (compared to only 6%, or 70,000 t, by trawlers in 2007). In Qatar, the number of artisanal fishers (+52%), the artisanal catch (+159%) and the size of artisanal-class vessels increased after closure of its bottom-trawl fishery in 1993 (Al-Abdulrazzak, 2013;El Sayed, 1996;FAO, 2003;Walton et al, 2018)…”

The role of environmental impact assessment in the sustainable artificial island development: A Qatar's Island case study

“…Infauna communities play a vital role in marine ecosystems because they maintain nutrient cycles; and provide adequate habitat and food sources, particularly for organisms that live at the bottom. Anthropogenic disturbance, tidal currents, and sediment structure are major and known to disrupt the infauna communities (Walton et al, 2018). The Gulf region's benthic species habitats are already facing multiple environmental stresses due to unplanned developments along with the shore and in marine spaces (Lavieren et al, 2011).…”

“…In 2018, a total of almost 603 species were spotted to analyze infaunal communities of Qatari waters. It was noticed that annelids, mollusks, and arthropods, a group of the three most noteworthy phyla, showed significant abundance (Walton et al, 2018). However, before the construction phase, the zooplankton population in the project area was of very low abundance and diversity.…”

“…Similarly, Pseudochromis aldabraensis was solely noticed in the coral reef ecosystem, and Epinephelinae spp, Dussumieria spp, and Parupeneus margaritatus were particularly found in sand. All other fish species recorded were not limited to specific habitats (Walton et al, 2018).…”