ICTIOFAUNA DE POÇAS DE MARÉ EM TERRAÇOS CONSOLIDADOS DO LITORAL AMAZÔNICO BRASILEIRO

As poças de maré são formadas pelo represamento de massas d’água durante a vazante e a sua troca ocorre ao longo de cada ciclo de marés, configurando em um ambiente explorado por várias espécies. A ictiofauna é um componente das poças de maré, algumas espécies são totalmente adaptadas (e.g. plasticidade fisológica, tamanho reduzido) e seu ciclo de vida ocorre apenas nas poças de maré. Contudo, muitas espécies utilizam as poças de maré em algumas fases do ciclo de vida para fins de alimentação, refúgio e reprodução. Considerando que os inventários são fundamentais para o conhecimento da biodiversidade, nosso estudo investigou a assembleia de peixes em poças de marés da Praia do Araçagy no período de outubro de 2016 a abril de 2017. No total, nós registramos 409 exemplares, pertencendo a 13 espécies, distribuídas em 11 famílias e sete ordens. Espécies residentes e estuarinas de importância comercial foram dominantes. INTERTIDAL FISHES OF THE CEMENTED TERRACES FROM BRAZILIAN AMAZON COAST: Tidal pools are formed by the damming of marine water during an ebb tide and their exchange occurs along each tidal cycle, configuring an environment explored by several species. The ichthyofauna is one of the components of the tide pools, with some species being fully adapted (e. g. physiological plasticity, reduced size) and their life cycles occuring uniquely on this environment. However, most species use tide pools at some stage of their life cycle for feeding, refuge and reproduction. Considering the main role of faunal inventories for the increase in biodiversity knowledge, this study investigates the fish assemblage in tide pools at Praia do Araçagy from October 2016 to April 2017. In total, were recorded 409 specimens belonging to 13 species, distributed in 11 families and seven orders. Resident and estuarine species with commercial importance were dominant.

Intertidal fishes of Mauritius with special reference to shallow tidepools

Intertidal fishes are found in large numbers and play an important role in their ecosystems, but knowledge of their ecology is still very limited in many tropical regions. Within this context, data from intertidal fishes in Mauritius were compiled from different sources and intertidal resident species were examined in Mauritian tidepools. A total of 292 fish species occurring in Mauritius were reported from intertidal habitats, of which 62 species represent permanent intertidal residents. The species number in the studied pools increased, not only with the proportion of stones and rock covering the pool bottom, but also with pool facilities, for example, the supply of boulders and a high coverage of macro-algae. All examined pools were dominated by two species, Bathygobius coalitus and Istiblennius edentulus. Their abundance increased with decreasing pool size, peaking in pools with a surface area between 1-2 m2 during the lowest level of ebb tide. This 'overcrowding effect' may be linked to the absence of predators in these very small pools. The comparison of present data with results of a survey made in the same area in 1995 suggested a decrease of resident species occurred during the last decades, probably linked to human influences, such as eutrophication and water pollution.

Regional and Seasonal Differences in Species Composition and Trophic Groups for Tidepool Fishes of a Western Pacific Island – Taiwan

Spatial and temporal variations in the species composition of assemblages are common in many marine organisms, including fishes. Variations in the fish species composition of subtidal coral reefs have been well documented, however much less is known about such differences for intertidal fish assemblages. This is surprising, given that intertidal fishes are more vulnerable to terrestrial human disturbances. It is critical to evaluate the ecology and biology of intertidal fishes before they are severely impacted by coastal development, especially in developing countries such as those in the tropical western Pacific region where coastal development is rapidly increasing. In this study, we investigated the species composition, abundance, biomass and species number (richness) for intertidal fish assemblages in subtropical (northern) and tropical (southern) Taiwan across four seasons by collecting fishes from tidepools using clove oil. We also examined the gut contents of collected fishes to identify their trophic functional groups in order to investigate regional and seasonal variations for different trophic groups. We found significant differences in the species composition of tidepool fish assemblages between subtropical and tropical Taiwan. Bathygobius fuscus, Abudefduf vaigiensis and Istiblennius dussumieri were dominant species in subtropical Taiwan, whereas Bathygobius coalitus, Abudefduf septemfasciatus and Istiblennius lineatus were dominant in tropical Taiwan. Other species such as Bathygobius cocosensis, Abudefduf sordidus and Istiblennius edentulus were common in both regions. For trophic groups, omnivores and detritivores had or showed trends towards higher species numbers and abundances in the subtropical region, whereas herbivores, planktivores and general carnivores had or showed trends towards higher species numbers and biomass in the tropical region. Overall, many intertidal fish species and trophic groups showed differences in abundance, biomass and species number between subtropical and tropical Taiwan. Further studies on large scale geographical gradients in trophic groups and species compositions in the Indo-west Pacific region are encouraged to assist with ecosystem monitoring and assessment. Keywords: Intertidal fishes, spatio-temporal pattern, feeding guild, diet

Littorally adaptive? Testing the link between habitat, morphology, and reproduction in the intertidal sculpin subfamily Oligocottinae (Pisces: Cottoidea)

While intertidal habitats are often productive, species-rich environments, they are also harsh and highly dynamic. Organisms that live in these habitats must possess morphological and physiological adaptations that enable them to do so. Intertidal fishes are generally small, often lack scales, and the diverse families represented in intertidal habitats often show convergence into a few general body shapes. However, few studies have quantified the relationship between phenotypes and intertidal living. Likewise, the diversity of reproductive traits and parental care in intertidal fishes has yet to be compared quantitatively with habitat. We examine the relationship of these characters in the sculpin subfamily Oligocottinae using a phylogenetic hypothesis, geometric morphometrics, and phylogenetic comparative methods to provide the first formal test of associations between fish phenotypes and reproductive characters with intertidal habitats. We show that the ability to live in intertidal habitats, particularly in tide pools, is likely a primitive state for Oligocottinae, with a single species that has secondarily come to occupy only subtidal habitats. Contrary to previous hypotheses, maximum size and presence of scales do not show a statistically significant correlation with depth. However, the maximum size for all species is generally small (250 mm or less) and all show a reduction in scales, as would be expected for an intertidal group. Also contrary to previous hypotheses, we show that copulation and associated characters are the ancestral condition in Oligocottinae, with copulation most likely being lost in a single lineage within the genus Artedius. Lastly, we show that body shape appears to be constrained among species with broader depth ranges, but lineages that occupy only a narrow range of intertidal habitats display novel body shapes, and this may be associated with habitat partitioning, particularly as it relates to the degree of wave exposure.

Littorally adaptive? Testing the link between habitat, morphology, and reproduction in the intertidal sculpin subfamily Oligocottinae (Pisces: Cottoidea)

While intertidal habitats are often productive, species-rich environments, they are also harsh and highly dynamic. Organisms that live in these habitats must possess morphological and physiological adaptations that enable them to do so. Intertidal fishes are generally small, often lack scales, and the diverse families represented in intertidal habitats often show convergence into a few general body shapes. However, few studies have quantified the relationship between phenotypes and intertidal living. Likewise, the diversity of reproductive traits and parental care in intertidal fishes has yet to be compared quantitatively with habitat. We examine the relationship of these characters in the sculpin subfamily Oligocottinae using a phylogenetic hypothesis, geometric morphometrics, and phylogenetic comparative methods to provide the first formal test of associations between fish phenotypes and reproductive characters with intertidal habitats. We show that the ability to live in intertidal habitats, particularly in tide pools, is likely a primitive state for Oligocottinae, with a single species that has secondarily come to occupy only subtidal habitats. Contrary to previous hypotheses, maximum size and presence of scales do not show a statistically significant correlation with depth. However, the maximum size for all species is generally small (250mm or less) and all show a reduction in scales, as would be expected for an intertidal group. Also contrary to previous hypotheses, we show that copulation and associated characters are the ancestral condition in Oligocottinae, with copulation most likely being lost in a single lineage within the genus Artedius. Lastly, we show that body shape appears to be constrained among species with broader depth ranges, but lineages that occupy only a narrow range of intertidal habitats display novel body shapes, and this may be associated with habitat partitioning, particularly as it relates to the degree of wave exposure.

Littorally adaptive? Testing the link between habitat, morphology, and reproduction in the intertidal sculpin subfamily Oligocottinae (Pisces: Cottoidea)

While intertidal habitats are often productive, species-rich environments, they are also harsh and highly dynamic. Organisms that live in these habitats must possess morphological and physiological adaptations that enable them to do so. Intertidal fishes are generally small, often lack scales, and the diverse families represented in intertidal habitats often show convergence into a few general body shapes. However, few studies have quantified the relationship between phenotypes and intertidal living. Likewise, the diversity of reproductive traits and parental care in intertidal fishes has yet to be compared quantitatively with habitat. We examine the relationship of these characters in the sculpin subfamily Oligocottinae using a phylogenetic hypothesis, geometric morphometrics, and phylogenetic comparative methods to provide the first formal test of associations between fish phenotypes and reproductive characters with intertidal habitats. We show that the ability to live in intertidal habitats, particularly in tide pools, is likely a primitive state for Oligocottinae, with a single species that has secondarily come to occupy only subtidal habitats. Contrary to previous hypotheses, maximum size and presence of scales do not show a statistically significant correlation with depth. However, the maximum size for all species is generally small (250mm or less) and all show a reduction in scales, as would be expected for an intertidal group. Also contrary to previous hypotheses, we show that copulation and associated characters are the ancestral condition in Oligocottinae, with copulation most likely being lost in a single lineage within the genus Artedius. Lastly, we show that body shape appears to be constrained among species with broader depth ranges, but lineages that occupy only a narrow range of intertidal habitats display novel body shapes, and this may be associated with habitat partitioning, particularly as it relates to the degree of wave exposure.

The mechanisms of intertidal fish coexistence: a model

Research into the ecology of intertidal fishes of the U.K. appears to be lacking, reportedly due to the mobility and cryptic nature of the more common species. However, some intertidal fishes contribute to the diets of commercially important species such as cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and near-threatened European otter (Lutra lutra). The current study contains the first comprehensive research into the ecology of intertidal fishes from the English, Yorkshire coast and Welsh, Anglesey coast, identifying and addressing the mechanisms which allow for their coexistence. Seven mechanisms were identified which promote interspecific fish coexistence. It was found that coexistence can occur when: (I) fish diversity on a shore is low, thus minimising high degrees of co-occurrence within pools, (II) co-occurrence on shores (at tidal height level) is minimal and when fishes do co-occur, they are of similar sizes thus reducing size-dominated hierarchies, (III) the significant variables which predict fish presences differ, (IV) there is an abundance of shelter/protection readily available, which reduces the competition to access such features, (V) morphology is such, that for the majority of the year, it is more profitable for the piscivorous fishes to predate on food items other than fish, (VI) competition for prey items is reduced, when variability of resources is high, and (VII) there is a difference in the most targeted prey items between fish species, despite some overlap in targeted prey items.

The mechanisms of intertidal fish coexistence: a model

Research into the ecology of intertidal fishes of the U.K. appears to be lacking, reportedly due to the mobility and cryptic nature of the more common species. However, some intertidal fishes contribute to the diets of commercially important species such as cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and near-threatened European otter (Lutra lutra). The current study contains the first comprehensive research into the ecology of intertidal fishes from the English, Yorkshire coast and Welsh, Anglesey coast, identifying and addressing the mechanisms which allow for their coexistence. Seven mechanisms were identified which promote interspecific fish coexistence. It was found that coexistence can occur when: (I) fish diversity on a shore is low, thus minimising high degrees of co-occurrence within pools, (II) co-occurrence on shores (at tidal height level) is minimal and when fishes do co-occur, they are of similar sizes thus reducing size-dominated hierarchies, (III) the significant variables which predict fish presences differ, (IV) there is an abundance of shelter/protection readily available, which reduces the competition to access such features, (V) morphology is such, that for the majority of the year, it is more profitable for the piscivorous fishes to predate on food items other than fish, (VI) competition for prey items is reduced, when variability of resources is high, and (VII) there is a difference in the most targeted prey items between fish species, despite some overlap in targeted prey items.