Seasonal and environmental influences on recruitment patterns and habitat usage among resident and transient fishes in a World Heritage Site subtropical estuary.
This study investigated whether the fish communities inhabiting shallow non-vegetated habitats in two divergent bays in a subtropical World Heritage Site estuarine system differed according to wet (spring-summer) and dry (autumn-winter) seasons or polyhaline and mesohaline zones, within the broader objective of facilitating spatio-temporal management. Species richness (total of 74 taxa; total length, LT= 11-552 mm) and abundance (51 109 individuals) were mostly greater in the wet than dry season and in polyhaline than mesohaline areas. There was a major effect of rainfall on recruitment, particularly among transient fishes, which could be the result of enhanced survival of young via greater productivity (food resources) and protection from predators (via turbidity reducing visual cues). Salinity had strong interactive effects with rainfall and temperature in one bay, with greater species richness and overall abundances as well as large abundances of four key species [Anchoa januaria and Atherinella brasiliensis (pelagic residents), Cetengraulis edentulus (pelagic transient) and Diapterus rhombeus (demersal transient)] during the wet season in polyhaline areas; possibly reflecting a biodiversity hotspot that might be affected by distance to the estuary mouth and convergence hydrology. Regionally, the results support enforcing spatio-temporal restrictions to minimize anthropogenic activities within statutory (but not always enforced) protected areas. Globally, the data reiterate the need to identify and understand biotic and abiotic effects on estuarine ichthyofaunal distributions and abundances as a precursor to their management.
Programa de Pós-Graduação em Biodiversidade Tropical, Centro Universitário Norte do Espírito Santo, Universidade Federal do Espírito Santo (UFES), Rodovia BR 101 Norte, km 60, Litorâneo, CEP 29932-540, São Mateus, ES, Brazil.
H A
HA
Pichler
WildFish Research, Grays Point NSW 2232, Australia and Biological, Earth and Environmental Sciences, University of New South Wales, NSW 2052, Australia.
C A
CA
Gray
NSW Department of Primary Industries, Fisheries Conservation Technology Unit, PO Box 4321, Coffs Harbour, NSW 2450, Australia and Marine and Estuarine Ecology Unit, School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
M K
MK
Broadhurst
Laboratório de Biologia de Peixes, Programa de Pós-Graduação em Sistemas Costeiros e Oceânicos, UFPR, CEP 83255-000, Pontal do Paraná, PR, Brazil.
H L
HL
Spach
School of Biological Sciences, Southern Seas Ecology Laboratories, The University of Adelaide, Adelaide, SA, 5005, Australia.
I
I
Nagelkerken
D000818:Animals; D061006:Bays; D001522:Behavior, Animal; D044822:Biodiversity; D063366:Estuaries; D005399:Fishes / Q000502:physiology*; D054712:Salinity; D012621:Seasons; D013696:Temperature
estuaries; ichthyofauna; mesohaline; non-vegetated habitat; polyhaline; rainfall effects