Size-based, seasonal, and multidirectional movements of an estuarine fish species in a habitat mosaic

2014 ◽  
Vol 507 ◽  
pp. 263-276 ◽  
Author(s):  
AB Barbour ◽  
AJ Adams ◽  
K Lorenzen
Koedoe ◽  
2012 ◽  
Vol 54 (1) ◽  
Author(s):  
Jan A. Venter ◽  
Bruce Q. Mann

A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.


2017 ◽  
Vol 15 (3) ◽  
Author(s):  
Francisco S. Álvarez ◽  
Wilfredo A. Matamoros ◽  
Francisco A. Chicas

ABSTRACT The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa.


2017 ◽  
Vol 4 ◽  
Author(s):  
Ross E. Boucek ◽  
Erin Leone ◽  
Joel Bickford ◽  
Sarah Walters-Burnsed ◽  
Susan Lowerre-Barbieri

2003 ◽  
Vol 55 (2) ◽  
pp. 137-159 ◽  
Author(s):  
G.D Stentiford ◽  
M Longshaw ◽  
B.P Lyons ◽  
G Jones ◽  
M Green ◽  
...  

2019 ◽  
Vol 36 (1) ◽  
pp. 125-127 ◽  
Author(s):  
Moulitharan Nallathambi ◽  
Jayakumar N ◽  
Uma Arumugam ◽  
Praveenraj Jayasimhan ◽  
Sudhan Chandran ◽  
...  

2009 ◽  
Vol 82 (4) ◽  
pp. 673-681 ◽  
Author(s):  
Maylis Labonne ◽  
Eric Morize ◽  
Pierre Scolan ◽  
Raymond Lae ◽  
Eric Dabas ◽  
...  

2017 ◽  
Vol 68 (5) ◽  
pp. 941 ◽  
Author(s):  
K. O'Mara ◽  
A. Miskiewicz ◽  
M. Y. L. Wong

Estuaries are critical aquatic environments that are used by many fish during their life cycle. However, estuaries often suffer from poor water quality as a result of anthropogenic activities. Fish diversity studies in estuaries are common, although few have examined whether correlations exist between water quality, metal contamination and fish assemblages. In the present study we investigated the effect of abiotic conditions, heavy metals and estuary characteristics on the abundance, diversity and composition of fish in four intermittently open estuaries along the Illawarra coast of south-eastern Australia. The heterogeneity of environmental conditions was reflected in the fish assemblages in each estuary. Environmental variables predicted fish species composition, and estuaries in particularly poor condition contained few species (estuarine residents) in high abundance, indicating their ability to acclimatise and survive in conditions that are hostile to other species. Overall, these findings demonstrate that estuarine fish assemblages may be useful indicators of estuary condition and reveal the importance of managing anthropogenic activities in the surrounding catchment to improve water quality so that biodiversity of fish can be restored in these estuarine environments.


2017 ◽  
Vol 74 (4) ◽  
pp. 1042-1050 ◽  
Author(s):  
Joshua Lonthair ◽  
Rasmus Ern ◽  
Andrew J. Esbaugh

Ocean acidification (OA) and other climate change induced environmental alterations are resulting in unprecedented rates of environmental deterioration. This environmental change is generally thought to be too fast for adaptation using typical evolutionary processes, and thus sensitivity may be dependent on the presence of existing tolerant genotypes and species. Estuaries undergo natural pCO2 fluctuations over a variety of time scales, and levels regularly exceed the predicted end of the century values. Interestingly, estuarine fish species have been overlooked in reference to the impacts of OA. Here, we use the estuarine red drum (Sciaenops ocellatus) as a model to explore the hypothesis that early life stages of estuarine species have intrinsic tolerance to elevated pCO2. Our sensitivity endpoints included: survival, growth, yolk consumption, heart rate, and scototaxis. Survival was significantly decreased when exposed to 1300 μatm and 3000 μatm, and coincided with a significant increase in heart rate at the 3000 μatm exposure. However, these effects were less pronounced than the findings of previous studies on other marine fish species. Yolk depletion rate and standard length were not significantly affected by pCO2. Scototaxis behaviour was also not significantly affected by exposure to elevated levels of pCO2 under both acute and acclimated exposure scenarios. Overall, these results support the hypothesis that estuarine life history and habitat usage may play a critical role in determining sensitivity of fish species to OA. Furthermore, estuarine species may provide present-day insight into the physiological and ecological foundation of OA tolerance.


Ecotoxicology ◽  
2008 ◽  
Vol 17 (7) ◽  
pp. 591-597 ◽  
Author(s):  
Pamela M. Bachman ◽  
Gary M. Rand

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