Development of a fish-based multimetric index to assess the ecological quality of marine habitats: the Marine Fish Community Index

A review of methods and indicators used to evaluate the ecological modifications generated by artificial structures on marine ecosystems

The current development of human activities at sea (e.g. land reclamation, maritime activity and marine renewable energy) is leading to a significant increase in the number of infrastructures installed in marine settings. These artificial structures provide new hard-bottom habitats for many marine organisms and can thus modify the structure and functioning of coastal ecosystems. In order to better evaluate the nature of these modifications as well as the potential benefits and/or impacts generated, it becomes essential to develop assessment methods that can be applied to a wide variety of study sites from harbours to coastal offshore environments. In this context, our study aims to review the different methods and indicators available which are used to measure the modifications of biodiversity and ecological functioning generated by such structures. Among the methods reviewed, we highlight some that were developed specifically for artificial structures, and others intended for various primary uses but which have been successfully transposed to artificial structures. Nevertheless, we also point out the lack of reliable methods concerning some biological ecosystem components impacted by artificial structures. In this context, we require the adaptation or creation of brand-new indicators to achieve a better characterisation of the ecological impacts generated by these structures. Overall, this study highlights a very high number of existing methods, which provide stakeholders with useful tools to study the impacts of artificial structures, and identifies the need to develop integrative indicators to enhance the deployment of new artificial structures.

The functional composition of nearshore fish communities demonstrated by trait analysis: Response to environmental gradients

There is limited understanding on nearshore fish community functioning in relation to changing environmental gradients. To address this, we investigated the trait composition of fish communities in five regions along the Portuguese coast during 4 years. Northern regions were characterized by higher Chlorophyll-α and small-sized species with short lifespans. The southernmost region was characterized by warmer waters, more intense upwelling events and typical warm-water species. Higher species richness and functional redundancy at the southernmost region suggested that in case of potential species loss, community functioning would be less affected in this region, and thus, a certain level of community resilience is maintained. The central region presented lower functional redundancy and high functional richness, which indicated the presence of rare species with rare traits, suggesting a more vulnerable community. This information on the nearshore fish community distribution may be particularly important towards managing coastal ecosystems in response to changing environmental conditions.

The development of a preliminary rock reef fish multimetric index for assessing thermal and urban impacts in a tropical bay

We developed a multimetric index for assessing ecological conditions in rocky reefs areas to evaluate thermal and urban influences on fish community. Eight metrics were selected to assess thermal influence: (1) total number of species; (2) number of water column species; (3) number of transient species; (4) density of individuals with low resilience; (5) density of omnivores; (6) density of carnivores; (7) number of cryptic species; (8) density of herbivores. For urban influence, six metrics were selected: (1) total density; (2) ratio between the number of rare species and the total number of species; (3) density of individuals with heavy fishing pressure; (4) number of resident species; (5) number of cryptic species; (6) density of herbivores. This preliminary index succeed in discriminating control/impacted sites and proved to be an important tool to assess impacts that alter fish community and have potential to be used in tropical rock reef coastal areas.

The utility of two marine community indices to assess the environmental degradation of lotic systems using fish communities

Multimetric approaches are commonly used to evaluate the ecological status of aquatic ecosystems. However, it has been recommended that the sensitivity of existing methods be improved through the investigation of the potential of new metrics to detect environmental disturbances. In this study we tested the effectiveness of two community indices (Taxonomic distinctness index (TDI) and Abundance biomass comparison (ABC) method), primarily proposed for marine ecosystems, to identify sites with different levels of environmental degradation in lotic systems using fish community data. Fish samples were collected over the period 2003-2011 at 131 sampling stations. To generate water and habitat quality classes, a self-organizing map (SOM) based on environmental data was applied. Gradients over the SOM map were investigated for the values of the TDI and ABC indices. The results of this study reveal that the values of both the TDI and ABC indices are highly correlated with water and habitat quality gradients. However, despite the observed correlation, the utility of TDI as a potential metric in bioassessment programs is rather limited, due to its lack of discriminatory power. In contrast, the ABC method could be proposed as a novel metric, but can only be applied in type-specific multimetric approaches.

Inventory of Chondrichthyes and Actinopterygii species collected in the central coast of São Paulo State, Brazil

This biodiversity inventory of the central coast of São Paulo State presents species of demersal and pelagic fishes of Santos Bay, Bertioga Channel, and adjacent continental shelf, between São Sebastião and Peruíbe, from the coast till a depth of 100 m. Samples were taken during oceanographic campaigns using otter trawls, between November 2004 and February 2006. A total of 56,095 individuals were collected, belonging to the classes Chondrichthyes (three orders and fourteen species) and Actinopterygii (fifteen orders and 141 species). This list adds 27 species to those explicitly cited for the coast of São Paulo state, contributing to the knowledge of this group.