Anabela Maia

Rhode Island College | RIC · Department of Biology

Large rivers are highly important systems that require close monitoring of the ecological consequences of factors like commercial and recreational exploitation, channel alterations, and climate change. The Long‐Term Survey and Assessment of Large River Fishes in Illinois (LTEF) monitors the fish communities of the Illinois, Mississippi, Wabash, and...

Estrogenic compounds including 17β estradiol (or E2) are known to negatively affect the reproductive system of many animals, including fish, leading to feminization, altered sex ratio, reduced fecundity, and decreased gonadosomatic index. The objective of this study was to evaluate the effects of varying concentrations of water-soluble 17β estradio...

The natural habitats of fish are increasingly contaminated through urban runoffs, excreta and effluents generated from wastewater treatment facilities. Estrogenic compounds, including 17-β estradiol (E2), are one of those several compounds and are of growing concern as they negatively affect human and aquatic health. Though the effect of E2 on the...

Decades of anthropogenic pressure have harmed riverscapes throughout North America by degrading habitats and water quality and can result in the extirpation of sensitive aquatic taxa. Local stream restoration projects have increased in frequency, but monitoring is still infrequent. In 2010, Kickapoo Creek in East Central Illinois was subjected to a...

A key feature of fish functional design is the presence of multiple fins that allow thrust vectoring and redirection of fluid momentum to contribute to both steady swimming and maneuvering. A number of previous studies have analyzed the function of dorsal fins in teleost fishes in this context, but the hydrodynamic function of dorsal fins in freely...

This study compares sand shiner (Notropis stramineus) and silverjaw (Ericymba buccata) minnows, in terms of the morphological shape changes of the upper, lower, and pharyngeal jaws over ontogeny. These two species of minnows initially feed on midge larvae and undergo an ontogenic prey shift. The traditional morphometrics measured-total length, snou...

Respiration rate in fish during exercising depends on swimming duration and how strenuous it is, among other factors. This higher oxygen demand is compensated by increasing gill ventilation frequency (respiration). White muscle recruitment leads to an oxygen deficit and an increase in oxygen uptake, which is referred to as Excessive Post-exercise O...

Anthropogenic habitat alteration disturbs fishes at the community and organismal levels, but effects are seldom related to the physiological processes. Metabolism is the most basic rate which may govern organismal life history and behavior, and can help explain ecological interactions of fish. We examined the energetics and distribution of Longear...

Dorsal fins of actinopterygian fishes are known to function to varying degrees as stabilizers and as propulsive elements that augment thrust from the caudal fin. However, little is known about the ability of elasmobranchs to control three-dimensional conformation of the dorsal fins during swimming, which may alter the force balance during locomotio...

Habitat degradation has negatively impacted Midwestern stream fish assemblages. Understanding the complex dynamics within these systems can help mitigate losses. Our objective was to assess and model fish communities within a Midwestern stream influenced by anthropogenic pressures. We examined assemblages within seven reaches along Kickapoo Creek i...

In their natural environment, fish must swim stably through unsteady flows and vortices, including vertical vortices, typically shed by posts in a flow, horizontal cross-flow vortices, often produced by a step or a waterfall in a stream, and streamwise vortices, where the axis of rotation is aligned with the direction of the flow. Streamwise vortic...

The otoliths of wild common sole, Solea solea, and Senegal sole, Solea senegalensis, from the Tagus and the Douro estuaries, and captive S. senegalensis were examined for the detection of anomalies. The anomalies detected were granules of crystals, a dark coloration over the entire otolith, a dark mark concentric to the nucleus and multiple nuclei....

Stability and procured instability characterize two opposing types of swimming, steady and maneuvering, respectively. Fins can be used to manipulate flow to adjust stability during swimming maneuvers either actively using muscle control or passively by structural control. The function of the dorsal fins during turning maneuvering in two shark speci...

The Senegal sole, Solea senegalensis, is a flatfish species distributed from the Bay of Biscay to the coast of South Africa. Although it is a species of high commercial value its spawning period remains poorly known. In the Tagus estuary, Portugal, two juvenile cohorts of this species colonize two independent nursery areas within the estuarine syst...

Organic and inorganic pollution can impact organisms directly and affect condition, growth and survival of juvenile fish which use estuaries as nurseries, and thereby affect marine adult populations quantitatively and qualitatively. Trace element contamination (Cu, Zn, Cd, Pb) in juveniles of commercial fish Solea solea, Solea senegalensis, Platich...

Analysing the estuarine use patterns of juveniles of marine migrant fish species is vital for identifying important sites for juveniles as well as the basic environmental features that characterize these sites for different species. This is a key aspect towards understanding nursery function. Various estuarine systems along the Portuguese coast (Mi...

Elasmobranchs are an important bycatch component in Portuguese artisanal fisheries, but there are no management or monitoring programs in place yet. This study analysed elasmobranch catches in a Portuguese west coast trammel net fishery. Thirty-seven sampling surveys were conducted aboard commercial fishing vessels on a seasonal basis between Octob...

Habitat modelling requires incorporation of both biotic and abiotic information. For juvenile flatfish the factors that most influence growth are water temperature, food abundance and predatory pressure. This study focuses on the impact the predator, the shore crab, Carcinus maenas, has on the foraging activity of sole, Solea senegalensis. The resu...

The distribution of Solea solea and Solea senegalensis in the Tagus estuary was studied following a small-scale approach. Preliminary sampling revealed that sole concentrated in two areas within their nursery grounds, the main subtidal channel and a large intertidal mudflat. Beam trawls were conducted intensively in the two areas in July 2006. Dept...

Connectivity is a critical property of marine populations, particularly for species with segregated juvenile and adult habitats. Knowledge of this link is fundamental in understanding population structure and dynamics. Young adults of commercially important fish species Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dice...

0-Group sole, Solea solea (Linnaeus, 1758) were sampled in four nursery grounds: two on the Northern French coast and two on the Portuguese coast. Juvenile sole were collected at the Vilaine estuary (Northern Bay of Biscay) in 1992, in the Authie estuary (Eastern English Channel) in 1997, and in the Douro and Tagus estuary (Northern and central Por...

Habitat specific growth rates and condition indices were estimated for Solea solea and Solea senegalensis, in two nursery areas within the Tagus estuary, at the end of the estuarine colonization process, in 2005. While in the uppermost nursery area the two species of sole live in sympatry, in the lower nursery only S. senegalensis is present. Daily...

SummaryA total of 262 shortfin mako sharks, Isurus oxyrinchus, was sampled from the swordfish longliners operating in the eastern North Atlantic. Most were juveniles, with only 3.4% mature. Based on cohort analysis, average growth was determined as 61.1 cm year−1 for the first year and 40.6 cm year−1 for the second year. There was a marked seasonal...

The relative importance of nursery areas and their relationships with several environmental variables were evaluated in nine estuarine systems along the Portuguese coast based on trawl surveys. Historical data were used to outline changes and trends in the nursery function of some of these estuaries over the past decades. The dominant flatfish spec...

Estuaries are among the most productive ecosystems and simultaneously among the most threatened by conflicting human activities which damage their ecological functions, namely their nursery role for many fish species. A thorough assessment of the anthropogenic pressures in Portuguese estuarine systems (Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mir...

The shortfin mako, Isurus oxyrinchus, is caught in the eastern North Atlantic as a regular bycatch of the surface-drift longline fishery, mainly directed towards swordfish, Xiphias gladius. Stomachs of 112 shortfin mako sharks, ranging in size from 64cm to 290cm fork length, showed teleosts to be the principal component of the diet, occurring in 87...

A shark tagging programme along the Portuguese coast was initiated in 2001 in collaboration with the National Marine Fisheries Service. From a total of 168 blue sharks (Prionace glauca) tagged, 34 sharks were recaptured (20% return rate) providing important information on this species' movement patterns for the area. A total of 28 sharks travelled...