Species identification of fish shoals using coupled split-beam and multibeam echosounders and two scuba-diving observational methods

David, Viviane; Mouget, Anne; Thiriet, Pierre; Perrot, Yannick; Goff, Loïc Le; Bianchimani, Olivier; Basthard-Bogain, Solène; Tristan, Estaque,; Justine, Richaume,; Sys, Jean-François; Cheminée, Adrien; Feunteun, Éric; Acou, Anthony; Brehmer, Patrice

doi:10.1016/j.jmarsys.2023.103905

Cited by 8 publications

(4 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Discussionmentioning

confidence: 99%

“…The watch officer started scientific fishing operations only when significant acoustic densities of pelagic fish were observed. Consequently, low densities or fish presence inshore in the survey area have probably been overlooked 66,67 . Any shift in the distribution of sardinella and other small pelagic stocks could lead to significant economic and social instabilities.…”

Section: Discussion Northern Spatial Shift Of Small Pelagicmentioning

confidence: 99%

See 1 more Smart Citation

Climate change impacts on small pelagic fish distribution in Northwest Africa: trends, shifts, and risk for food security

Sarre,

Demarcq,

Keenlyside

et al. 2024

Sci Rep

Self Cite

View full text Add to dashboard Cite

Climate change is recognised to lead to spatial shifts in the distribution of small pelagic fish, likely by altering their environmental optima. Fish supply along the Northwest African coast is significant at both socio-economic and cultural levels. Evaluating the impacts of climatic change on small pelagic fish is a challenge and of serious concern in the context of shared stock management. Evaluating the impact of climate change on the distribution of small pelagic fish, a trend analysis was conducted using data from 2363 trawl samplings and 170,000 km of acoustics sea surveys. Strong warming is reported across the Southern Canary Current Large Marine Ecosystem (CCLME), extending from Morocco to Senegal. Over 34 years, several trends emerged, with the southern CCLME experiencing increases in both wind speed and upwelling intensity, particularly where the coastal upwelling was already the strongest. Despite upwelling-induced cooling mechanisms, sea surface temperature (SST) increased in most areas, indicating the complex interplay of climatic-related stressors in shaping the marine ecosystem. Concomitant northward shifts in the distribution of small pelagic species were attributed to long-term warming trends in SST and a decrease in marine productivity in the south. The abundance of Sardinella aurita, the most abundant species along the coast, has increased in the subtropics and fallen in the intertropical region. Spatial shifts in biomass were observed for other exploited small pelagic species, similar to those recorded for surface isotherms. An intensification in upwelling intensity within the northern and central regions of the system is documented without a change in marine primary productivity. In contrast, upwelling intensity is stable in the southern region, while there is a decline in primary productivity. These environmental differences affected several small pelagic species across national boundaries. This adds a new threat to these recently overexploited fish stocks, making sustainable management more difficult. Such changes must motivate common regional policy considerations for food security and sovereignty in all West African countries sharing the same stocks.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussion Northern Spatial Shift Of Small Pelagicmentioning

confidence: 99%

Climate change impacts on small pelagic fish distribution in Northwest Africa: trends, shifts, and risk for food security

Sarre,

Demarcq,

Keenlyside

et al. 2024

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…The watch o cer started scienti c shing operations only when signi cant acoustic densities of pelagic sh were observed. Consequently, low densities or sh presence inshore in the survey area have probably been overlooked (Brehmer et al, 2006;David et al, 2024).…”

Section: Environmental Trendsmentioning

confidence: 99%

Spatial shift of small pelagic fish in North-West Africa related to long-term intense warming and local decrease in marine productivity

SARRE,

DEMARCQ,

KEENLYSIDE

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

Along the coast of North-West Africa, fish supply is important at both socio-economic and cultural levels while threatened by climatic changes. To assess the impact of climate change on the distribution of small pelagic fish, a comprehensive trend analysis was conducted using data from 2,363 trawl samplings and 170,000 km of acoustics sea surveys spanning the period 1995–2015. The approach included estimating eight northern small pelagic species' presence and acoustics spatial distribution of the sardinella. The analysis incorporated key environmental variables, including sea temperature, chlorophyll-a concentration, and a wind-based Ekman upwelling index. The Southern Canary Current Large Marine Ecosystem (CCLME) was divided into five distinct ecological areas, extending from Morocco to Senegal, providing a spatialized perspective on the dynamic changes unfolding within these characteristic areas. Then, yearly averages of the monthly data per area were calculated. Strong warming is reported in all five areas. Over 34 years, from 1988 to 2021, several discernible trends emerged, with the southern CCLME experiencing increases in both wind speed and upwelling intensity, particularly in areas where the coastal upwelling was already the strongest. Despite upwelling-induced cooling mechanisms, sea surface temperature increased in most areas, indicating the complex interplay of climatic-related stressors in shaping the marine ecosystem. Concomitant northward shifts in the distribution of sardinella and other species were attributed to long-term warming trends in sea surface temperature (SST). As a result, the abundance of Sardinella aurita, the most abundant species along the coast, has increased in the subtropics (north part) and fallen in the intertropical region (south part). Independent environmental and ecological observational time series confirm a northward shift of around 180 km in one decade for S. aurita, while S. maderensis did not move significantly. Spatial shifts in biomass from 30 to 145 kilometers were observed for six other exploited small pelagic species, similar to those recorded for surface isotherms. An intensification in upwelling intensity within the northern and central regions of the system is documented without change in marine primary productivity. In contrast, a stable upwelling intensity is reported in the southern region (Senegal), which is associated with a decline in primary productivity. These environmental differences were associated with several small pelagic species beyond national boundaries whose recent overexploitation adds a new threat to their sustainable future in the whole region. Such changes must motivate common regional policy considerations for food security and sovereignty in all West African countries sharing the same stocks.

show abstract

“…The most abundant species were C. chromis and genus Spicara Rafinesque, 1810. That can be explained by the shoaling behaviour of the above taxa [65,66]. It seems that the formation of shoals besides the widely known advantages of predation avoidance, feeding and reproduction success, it offers other advantages mainly of energy consumption by reducing the metabolic rates [67].…”

Section: Plos Onementioning

confidence: 99%

Assessing the fish fauna diversity and abundance at Aegean and Ionian seas, with emphasis on certain NIS fish species via Scientific diving and Visual Census

Kampouris,

Pappou,

Erga

et al. 2023

PLoS ONE

View full text Add to dashboard Cite

The Mediterranean Sea and its exceptional biodiversity suffer from non-indigenous (NIS) and invasive species. These result from Lessepsian migration and human activities. Species with the highest negative impact include Pterois miles, Lagocephalus sceleratus and Fistularia commersonii. The current study assessed the distribution and abundance of these three species in the Aegean and Ionian Seas in the context of the regional diversity of ichthyofauna. Using Scientific Diving and Visual Census, we focused on NIS fish fauna, and surveyed most of the areas where the occurrence or establishment of NIS had been documented. Emphasis was given to regions with limited available data. This study assessed the homogeneity of diversity and abundance of the fish species at the diving sites; assessed the most dominant species per region; and calculated relevant biodiversity indexes. Our results suggest that the south and east parts of the Aegean Sea are the most affected by the establishment of NIS. Samos Island is concluded to be an important region for the expansion of NIS to the northern parts of the Aegean Sea. Also, both the Saronikos Gulf and the whole area of the Peloponnese seem to have a pivotal role in the expansion of distribution of NIS from the east Mediterranean sub-basin to the west sub-basin. The genus Siganus seems to have very high abundances and population densities in certain areas, and therefore its establishment could have negative impacts in these regions. We conclude that scientific diving is not appropriate for monitoring the population status of L. sceleratus and we propose more appropriate methodologies such as the use of baited cameras and ROV’s to be used in the future.

show abstract

Species identification of fish shoals using coupled split-beam and multibeam echosounders and two scuba-diving observational methods

Cited by 8 publications

References 57 publications

Climate change impacts on small pelagic fish distribution in Northwest Africa: trends, shifts, and risk for food security

Climate change impacts on small pelagic fish distribution in Northwest Africa: trends, shifts, and risk for food security

Spatial shift of small pelagic fish in North-West Africa related to long-term intense warming and local decrease in marine productivity

Assessing the fish fauna diversity and abundance at Aegean and Ionian seas, with emphasis on certain NIS fish species via Scientific diving and Visual Census

Contact Info

Product

Resources

About