| ANTHROPOGENIC ACTIVITIES DIFFERENTIALLY IMPACT FISH GUILDS: THE IMPORTANCE OF UNDERSTANDING LIFE HISTORY CHARACTERISTICS |
| McKINLEY, Andrew C.**, Cian Foster-Thorpe*, Anthony Miskiewicz1, Matthew D. Taylor* & Emma L. Johnston*; ** andrew.mckinley@hotmail.com *Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
1Environment and Strategic Planning, Wollongong City Council, 41 Burelli Street, Wollongong, New South Wales 2500, Australia tmiskiewicz@wollongong.nsw.gov.au |
| Life cycle and reproductive characteristics of fish play an important role in determining their sensitivity to environmental modification. Relationships between life history characteristics, habitat modification, and contaminants have rarely been assessed for the larvae of marine and estuarine fish. We investigated the large-scale distribution of stressors and relative sensitivity of larval fish guilds in estuarine environments. Larval fish communities were collected using a surface tow and a bottom trawl. We sampled multiple sites within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Community composition differed significantly between heavily modified and relatively unmodified estuaries and by sampling depth. Species were classified into guilds according to estuarine usage and spawning characteristics. Larvae of estuarine species and benthic spawners showed the greatest response to modification. These guilds were significantly more abundant in the bottom waters of modified estuaries. Estuarine opportunist species trended towards higher abundance in the surface waters of relatively unmodified systems. Differences in larval community composition were strongly related to sediment metal contamination and reduced seagrass cover in modified estuaries. Much greater impacts were observed in the bottom compared to surface samples suggesting that bottom trawling alone is sufficient for future monitoring. These findings suggest that contamination and habitat alteration have substantially different effects on larvae of different ecological guilds. The life history characteristics of early life stages represent a valuable tool for predicting the sensitivity of fish to anthropogenic impacts. |
| back |
|
|
 |
