Azeez Olalekan, Baki (MSc Thesis 2024)

Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1995–2022 in the Basque coast (southeastern Bay of Biscay).
Supervisors: Iñigo Muxika, Izaskun Zorita (AZTI)
The introduction of invasive alien species represents one of the most important drivers of biodiversity loss and ecosystem functioning, with effects ranging from ecological to economic and human health. This study presents an updated list of 373 marine macroinvertebrate species that can be considered alien, cryptogenic, and invasive in the Bay of Biscay from three recent publications and two public sources. After carefully cleaning and correcting any incorrect naming conventions and checking the WoRMs database, 26,974 benthic species records of macroinvertebrates obtained from surveys carried out from 1995 to 2022 on the Basque coast were crossed against this list to identify non-indigenous species (NIS). 56 NIS were identified on the Basque coast and estuaries. Spearman correlation showed a significant increasing trend between the number of NIS and the years of the study. The Nerbioi estuary emerges as a hotspot of NIS, with relatively high records of Pseudopolydira paucibranchiata (n=43, 26.4%), Monocorophium acherusicum (n=16, 9.8%), Grandidierella japonica (n=13, 8.0%), Ruditapes philippinarum (n=13, 8.0%), Theora lubrica (n=11, 6.8%), and Xenostrobus securis (n=11, 6.8%) found in the intermediate part of the estuary, where historical industrial activity was settled. Oxygen saturation was a limiting factor for fauna in the inner and intermediate parts. The increase in NIS in the Nerbioi estuary was not correlated with the number of vessels, which suggests that factors other than maritime traffic contribute to the establishment and expansion of the NIS. Our data showed that none of the NIS found on the Basque coast could be considered an invasive species of concern for the European Union, except for the mussel Xenostrobus securis, which is of particular concern in Spain. Thus, developing a specific monitoring system focused on NIS is essential to monitor the establishment and spread of alien species and implement measures to prevent the establishment of newly introduced invasive alien species. Keywords: Invasive, Cryptogenic, Non-indigenous species, Soft-bottom macroinvertebrates, Spatial distribution, Southeastern Bay of Biscay

Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1995–2022 in the Basque coast (southeastern Bay of Biscay).

Supervisors: Iñigo Muxika, Izaskun Zorita (AZTI)

The introduction of invasive alien species represents one of the most important drivers of biodiversity loss and ecosystem functioning, with effects ranging from ecological to economic and human health. This study presents an updated list of 373 marine macroinvertebrate species that can be considered alien, cryptogenic, and invasive in the Bay of Biscay from three recent publications and two public sources. After carefully cleaning and correcting any incorrect naming conventions and checking the WoRMs database, 26,974 benthic species records of macroinvertebrates obtained from surveys carried out from 1995 to 2022 on the Basque coast were crossed against this list to identify non-indigenous species (NIS). 56 NIS were identified on the Basque coast and estuaries. Spearman correlation showed a significant increasing trend between the number of NIS and the years of the study. The Nerbioi estuary emerges as a hotspot of NIS, with relatively high records of Pseudopolydira paucibranchiata (n=43, 26.4%), Monocorophium acherusicum (n=16, 9.8%), Grandidierella japonica (n=13, 8.0%), Ruditapes philippinarum (n=13, 8.0%), Theora lubrica (n=11, 6.8%), and Xenostrobus securis (n=11, 6.8%) found in the intermediate part of the estuary, where historical industrial activity was settled. Oxygen saturation was a limiting factor for fauna in the inner and intermediate parts. The increase in NIS in the Nerbioi estuary was not correlated with the number of vessels, which suggests that factors other than maritime traffic contribute to the establishment and expansion of the NIS. Our data showed that none of the NIS found on the Basque coast could be considered an invasive species of concern for the European Union, except for the mussel Xenostrobus securis, which is of particular concern in Spain. Thus, developing a specific monitoring system focused on NIS is essential to monitor the establishment and spread of alien species and implement measures to prevent the establishment of newly introduced invasive alien species.

Keywords: Invasive, Cryptogenic, Non-indigenous species, Soft-bottom macroinvertebrates, Spatial distribution, Southeastern Bay of Biscay

Azeez Olalekan, Baki (MSc Thesis 2024)

Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1995–2022 in the Basque coast (southeastern Bay of Biscay).

Location